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4. Epidemiology: vector-host and vector-parasite interactions

[See also 25: nos. 12392, 12421, 12434]

5. Human trypanosomiasis

(a) Surveillance

12402 Chappuis, F., Pittet, A., Bovier, P.A., Adams, K., Godineau, V., Hwang, S.Y., Magnus, E. & Büscher, P., 2002. Field evaluation of the CATT/Trypanosoma brucei gambiense on blood-impregnated filter papers for diagnosis of human African trypanosomiasis in southern Sudan. Tropical Medicine and International Health, 7: (11): 942-948.

Chappuis: MSF-Switzerland, rue du Lac 12, 1211 Geneva 6, Switzerland. []

Most human African trypanosomiasis (HAT) control programmes in areas endemic for Trypanosoma brucei gambiense rely on a strategy of active mass screening with the Card Agglutination Test for Trypanosomiasis (CATT)/T. b. gambiense. We evaluated the performance, stability and reproducibility of the CATT/T. b. gambiense on blood-impregnated filter papers (CATT-FP) in Kajo-Keji County, South Sudan, where some areas are inaccessible to mobile teams. The CATT-FP was performed with a group of 100 people with a positive CATT on whole blood including 17 confirmed HAT patients and the results were compared with the CATT on plasma (CATT-P). The CATT-FP was repeated on impregnated filter papers stored at ambient and refrigerated temperature for 1, 3, 7 and 14 days. Another 82 patients with HAT, including 78 with a positive parasitology, were tested with the CATT-FP and duplicate filter paper samples were sent to a reference laboratory to assess reproducibility. The CATT-FP was positive in 90 of 99 patients with HAT (sensitivity: 91 percent). It was less sensitive than the CATT-P (mean dilution difference: -2.5). There was no significant loss of sensitivity after storage for up to 14 days both at ambient and cool temperature. Reproducibility of the CATT-FP was found to be excellent (k: 0.84). The CATT-FP can therefore be recommended as a screening test for HAT in areas where the use of CATT-P is not possible. Further studies on larger population samples in different endemic foci are still needed before the CATT-FP can be recommended for universal use.

12403 Lejon, V., Legros, D., Richer, M., Ruiz, J.A., Jamonneau, V., Truc, P., Doua, F., Djé, N., N'Siesi, F.X., Bisser, S., Magnus, E., Wouters, I., Konings, J., Vervoort, T., Sultan, F. & Büscher, P., 2002. IgM quantification in the cerebrospinal fluid of sleeping sickness patients by a latex card agglutination test. Tropical Medicine and International Health, 7 (8): 685-692.

Lejon: Department of Parasitology, Institute of Tropical Medicine, Nationalestraat 155, B-2000 Antwerpen, Belgium. []

An increased IgM concentration in cerebrospinal fluid (CSF), occurring as a consequence of massive intrathecal IgM synthesis, is a marker of interest for diagnosis of the meningo-encephalitic stage in human African trypanosomiasis. However, in current practice, IgM in CSF is not determined because of the lack of a simple and robust test that is applicable in African rural regions where the disease prevails. We describe the development of a sensitive semiquantitative card agglutination test, LATEX/IgM, for IgM quantification in CSF. The test is simple and fast and the lyophilized reagent remains stable even at 45 °C. CSF end-titres obtained with LATEX/IgM parallel the IgM concentrations determined by nephelometry and enzyme-linked immunosorbent assay. Detection of intrathecal IgM synthesis is the most sensitive marker for CNS involvement in sleeping sickness. At a cut-off value ³8, the sensitivity and specificity of LATEX/IgM for intrathecal IgM synthesis are 89.4 and 92.7 percent. As a consequence, patients with LATEX/IgM end-titres ³8 are likely to have intrathecal IgM synthesis, thus central nervous system involvement and therefore should be treated accordingly. Further studies should concentrate on the relationship between the LATEX/IgM end-titres, presence of intrathecal IgM synthesis and occurrence of treatment failures in patients treated with pentamidine.

12404 Radwanska, M., Claes, F., Magez, S., Magnus, E., Perez-Morga, D., Pays, E. & Büscher, P., 2002. Novel primer sequences for polymerase chain reaction-based detection of Trypanosoma brucei gambiense. American Journal of Tropical Medicine and Hygiene, 67 (3): 289-295.

Radwanska: Department of Parasitology, Institute for Tropical Medicine, Nationalestraat 155, 2000 Antwerp, Belgium. []

Progress in diagnosis, treatment, and epidemiology of human African trypanosomiasis (sleeping sickness) depends on the existence of specific and sensitive diagnostic tools. Inherent shortcomings of serologic and parasitologic diagnostic methods can be overcome by molecular techniques. Therefore, we have developed a new polymerase chain reaction (PCR) test using primers derived from the recently identified sequence of the Trypanosoma brucei gambiense-specific glycoprotein (TgsGP). The specificity of the TgsGP-PCR was evaluated on DNA extracted from 73 different trypanosome populations belonging to diverse taxonomic groups that were isolated from various host species, and from different geographic origins. The TgsG-PCR was shown to be specific for T. b. gambiense and was suitable for detection of trypanosome DNA in blood samples of patients with confirmed sleeping sickness.

12405 Truc, P., Lejon, V., Magnus, E., Jamonneau, V., Nangouma, A., Verloo, D., Penchenier, L. & Büscher, P., 2002. Evaluation of the micro-CATT, CATT/Trypanosoma brucei gambiense, and LATEX/T. b. gambiense methods for serodiagnosis and surveillance of human African trypanosomiasis in West and Central Africa. Bulletin of the World Health Organization, 80 (11): 882-886.

Truc: IRD UR035, OCEAC, BP 288, Yaoundé, Cameroon. []

The objective of this study was to evaluate the performance of serological tests using dried blood on filter-papers (micro-card agglutination test for trypanosomiasis (micro-CATT)) performed under field and laboratory conditions and using whole blood ((CATT/T. b. gambiense) (wb-CATT) and latex agglutination (LATEX/T. b. gambiense) (wb-LATEX)) for the serodiagnosis and surveillance of human African trypanosomiasis in West and Central Africa. We evaluated the micro-CATT, wb-CATT and wb-LATEX methods in Côte d'Ivoire and the Central African Republic by screening 940 people. Sensitivity and specificity were calculated for each serological test; only patients with the confirmed presence of trypanosomes in the blood or lymph aspirate were considered true positives. Positive and negative predictive values were also calculated. Each of the tests showed a lower sensitivity in the Central African Republic than in Côte d'Ivoire. The results confirmed the efficiency of the classic wb-CATT to detect sleeping sickness patients. The micro-CATT method can be used for human African trypanosomiasis surveillance if the test is performed on the same day as the blood collection, or if samples are stored at 4 °C. Otherwise, micro-CATT can be used when absolute sensitivity is notrequired. The technique based on wb-LATEX should only be used for high-specificity screening.

(b) Pathology and immunology

(c) Treatment

12406 Blum, J. & Burri, C., 2002. Treatment of late stage sleeping sickness caused by T. b. gambiense: a new approach to the use of an old drug. Swiss Medical Weekly, 132 (5-6): 51-56.

Blum: Swiss Tropical Institute, Socinstrasse 57, PO Box CH-4002 Basel, Switzerland. []

Melarsoprol is the standard treatment of late-stage trypanosomiasis. The development of treatment schedules was previously purely empirical. Generally melarsoprol is given in three series of three to four consecutive injections, given every 24 hours, with an interval of about one week between the series. Based on pharmacokinetic analysis, computer simulations and extensive literature research covering all schedules previously used and tested, a new schedule, consisting of ten daily consecutive doses of 2.16 mg/kg of the drug was suggested. The pharmacokinetic model was validated in uninfected vervet monkeys. No unexpected drug accumulation and no systemic toxic effects were observed. In a pilot clinical trial in Congo RDC a small group of T. b. gambiense patients (n = 11) was treated successfully with the new schedule. In an open randomized clinical trial conducted in 500 patients in Angola the clinical efficacy and safety of this new concise treatment were compared with those of standard protocol treatment. Parasitological cure 24 hours after treatment was 100 percent in both groups. Statistical analysis yielded no significant differences for adverse events between the two treatment protocols. The new schedule reduces the amount and cost for the drug by about one third, and those for hospitalization by about a half.

12407 Conway-Klaassen, J.M., Wyrick-Glatzel, J.M., Neyrinck, N. & Belair, P.A., 2002. African sleeping sickness in a young American tourist. Laboratory Medicine, 33 (10): 783-788.

Conway-Klaassen: Clinical Laboratory Sciences Program, University of Nevada, Las Vegas, NV, USA.

An account is given of the symptoms, diagnosis, clinical treatment and recovery of an 18-year old male tourist, who had contracted trypanosomiasis during a tour that included parts of Kenya and Tanzania.

12408 Jennings, F.W., Rodgers, J., Bradley, B., Gettinby, G., Kennedy, P.G.E. & Murray, M., 2002. Human African trypanosomiasis: Potential therapeutic benefits of an alternative suramin and melarsoprol regimen. Parasitology International, 51 (4): 381-388.

Rodgers: Department of Veterinary Clinical Studies, University of Glasgow Veterinary Clinical Studies, University of Glasgow Veterinary School, Bearsden Road, Glasgow G61 1QH, UK. []

Treatment of late-stage human African trypanosomiasis is complicated by the presence of trypanosomes within the central nervous system (CNS). The regimen commonly prescribed to treat CNS-stage disease involves the use of the trypanocidal drugs suramin and melarsoprol. Suramin does not cross the blood-brain barrier efficiently and therefore, at normal dosages, will not cure CNS-stage infections. An initial treatment with suramin is given to eliminate the parasites from the peripheral tissues. This is followed by a course of intravenous melarsoprol, which can enter the CNS. However, melarsoprol not only produces severe adverse reactions but also is extremely painful to administer. One possible method to help alleviate these problems is to reduce the total amount of melarsoprol in the treatment regimen. This study indicates a synergism between suramin and melarsoprol and demonstrates that experimental murine CNS-trypanosomiasis can be cured with a single intraperitoneal dose of 20 mg/kg suramin followed almost immediately by 0.05 ml (4.5 mmol) topical melarsoprol. These dosages will not cure the infection when administered as monotherapies. Moreover, the timing of the drug administration appears to be crucial to the successful outcome of the regimen. If the interval between injection of suramin and application of topical melarsoprol is extended from 15 min to three or seven days, the infections are not cured, although extended relapse times occur following these regimens when compared with monotherapy approaches. Thus, there is strong evidence that injected suramin and topical melarsoprol should be given almost simultaneously to achieve the most effective combination of the two drugs.

12409 Legros, D., Ollivier, G., Gastellu-Etchegorry, M., Paquet, C., Burri, C., Jannin, J. & Büscher, P., 2002. Treatment of human African trypanosomiasis - present situation and needs for research and development. Lancet Infectious Diseases, 2 (7): 437-440.

Legros: Epicentre, 8 rue Saint Sabin, 75011 Paris, France. []

Human African trypanosomiasis re-emerged in the 1980s. However, little progress has been made in the treatment of this disease over the past decades. The first-line treatment for second-stage cases is melarsoprol, a toxic drug in use since 1949. High therapeutic failure rates have been reported recently in several foci. The alternative, eflornithine, is better tolerated but difficult to administer. A third drug, nifurtimox, is a cheap, orally administered drug not yet fully validated for use in human African trypanosomiasis. No new drugs for second-stage cases are expected in the near future. Because of resistance and the limited number of current treatments, there may soon be no effective drugs available to treat trypanosomiasis patients, especially second-stage cases. Additional research and development efforts must be made for the development of new compounds, including: testing combinations of current trypanocidal drugs, completing the clinical development of nifurtimox and registering it for trypanosomiasis, completing the clinical development of an oral form of eflornithine, pursuing the development of DB 289 and its derivatives, and advancing the pre-clinical development of megazol, eventually engaging firmly in its clinical development. Partners from the public and private sector are already engaged in joint initiatives to maintain the production of current drugs. This network should go further and be responsible for assigning selected teams to urgently-needed research projects with funds provided by industry and governments. At the same time, on a long term basis, ambitious research programmes for new compounds must be supported to ensure the sustainable development of new drugs.

12410 Lejon, V., Lardon, J., Kenis, G., Pinoges, L., Legros, D., Bisser, S., N'Siesi, X., Bosmans, E. & Büscher, P., 2002. Interleukin (IL)-6, IL-8 and IL-10 in serum and CSF of Trypanosoma brucei gambiense sleeping sickness patients before and after treatment. Transactions of the Royal Society of Tropical Medicine and Hygiene, 96 (3): 329-333.

Lejon: Department of Parasitology, Institute of Tropical Medicine, Nationalestraat 155, B-2000 Antwerpen, Belgium. []

Serum and cerebrospinal fluid (CSF) concentrations of interleukin (IL)-6, IL-8, IL-10, tumour necrosis factor-á and interferon-g were determined in 46 Trypanosoma brucei gambiense sleeping sickness patients in DR Congo, before and after treatment. According to their CSF cell number before treatment, patients were classified as early-stage (0-5 cells/ml), intermediate-stage (6-20 cells/ml) or late-stage patients (>20 cells/ml). In serum, slightly higher IL-8 concentrations were found in early-stage patients compared with intermediate- or late-stage patients. These high IL-8 levels dropped after treatment. Higher IL-10 concentrations were detected in serum of patients in intermediate- or late-stage compared with early-stage patients. In both intermediate- and late-stage groups, serum IL-10 decreased after treatment. In CSF, elevated concentrations of IL-6, IL-8 and especially of IL-10 were observed in late-stage T. b. gambiense patients. After treatment, these concentrations dropped to levels similar to those of the other patients. Tumour necrosis factor-á was detected only in a few serum and CSF samples, which were scattered over the different patient groups. Interferon-g was detected in serum of five patients and remained undetectable in CSF.

12411 Mpia, B. & Pépin, J., 2002. Combination of eflornithine and melarsoprol for melarsoprol-resistant Gambian trypanosomiasis. Tropical Medicine and International Health, 7 (9): 775-779.

Pépin: Centre for International Health, 3001, 12ème Avenue Nord, Sherbrooke, Quebec, Canada J1H 5N4. []

The objective was to evaluate the efficacy and toxicity of a combination of eflornithine and melarsoprol among relapsing cases of Gambian trypanosomiasis. Forty-two late-stage Trypanosoma brucei gambiense trypanosomiasis patients relapsing after initial treatment with melarsoprol were treated with a sequential combination of intravenous eflornithine (100 mg/kg every six hours for four days) followed by three daily injections of melarsoprol (3.6 mg/kg, up to 180 mg). They were then followed up for 24 months. Two (4.8 percent) patients died during treatment. Of the 40 surviving patients, two had a treatment failure, 13 and 19 months after having received the combination therapy.By Kaplan-Meier analysis, the two-year probability of cure was 93.3 percent (95 percent confidence interval: 84.3-100 percent). This sequential combination has an efficacy and a toxicity similar to a seven-day course of eflornithine monotherapy, but is easier to administer. Whether such therapeutic success corresponds to synergism between eflornithine and melarsoprol, or merely means that four days of eflornithine monotherapy suffices for such patients, will need to be determined in a comparative trial.

12412 Ruiz, J.A., Simarro, P.P. & Josenando, T., 2002. Control of human African trypanosomiasis in the Quiçama focus, Angola. Bulletin of the World Health Organization, 80 (9): 738-745.

Simarro: WHO, PO Box 155 Yaoundé, Cameroon. []

The objective was to update the epidemiological status of human African trypanosomiasis (HAT), also known as sleeping sickness, in the Quiçama focus, province of Bengo, Angola, and to establish a HAT control programme. In 1997, 8 796 people (the population of 31 villages) were serologically screened for Trypanosoma brucei gambiense, the causative agent of HAT. In 1998 and 1999, surveys were carried out in villages where HAT cases had been identified in 1997. Individuals were screened using the card agglutination trypanosomiasis test (CATT), and then examined for the presence of the parasite. CATT-positive individuals in whom the presence of the parasite could not be confirmed were further tested with the CATT using serum dilutions, and those with a positive antibody end titre of 1-in-4 or above were followed up. Patients with £10 white cells/ml and no trypanosomes in their cerebrospinal fluid (CSF) were classified as being in the first stage of the disease. Vector control was not considered necessary or feasible. It was found that the main transmission areas were on the Kwanza riverbanks, where 5 042 inhabitants live. In 1997, the HAT prevalence was 1.97 percent, but this decreased to 0.55 percent in 1998 and to 0.33 percent in 1999. The relapse rate was 3 percent in patients treated with pentamidine and 1.5 percent in patients treated with melarsoprol. In patients treated with pentamidine, there was no difference in the relapse rate for patients with initial CSF white cell counts of 0-5 cells/ml or 6-10 cells/ml. The overall mortality rate was 0.6 percent and the rate of reactive arsenical encephalopathy among the melarsoprol-treated patients was 1.7 percent. In conclusion, the epidemiological status of the disease was updated and the transmission areas were defined. The control methods implemented allowed the disease prevalence to be reduced. A map of the study area is given.

6. Animal trypanosomiasis

(a) Survey and distribution

12413 Kidanemariam, A., Hadgu, K. & Sahle, M., 2002. Parasitological prevalence of bovine trypanosomosis in Kindo Koisha district, Wollaita zone, south Ethiopia. Onderstepoort Journal of Veterinary Research, 69 (2): 107-113.

Kidanemariam: Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, Private Box X04 Onderstepoort, 0110 South Africa.

A cross-sectional survey to determine the distribution and prevalence of trypanosomosis was conducted in Kindo Koisha district, in the Wollaita zone in southern Ethiopia. A total of 1 008 adult cattle was examined at eight different localities. Dark field examination of the buffy coat, as well as stained thin blood film examination and packed cell volume (PCV) evaluation were the diagnostic techniques used. The overall prevalence of bovine trypanosomosis was 15 percent. Among the positive animals, 108 (71.1 percent), 43 (28.4 percent) and 1 (0.6 percent) were due to Trypanosoma vivax, Trypanosoma congolense and mixed infection (T. vivax and T. congolense), respectively. The infection rate of T. vivax and T. congolense varied significantly (P<0.01). The mean PCV of the positive and negative animals ranged between 18.3-32.1 percent and 26.8-33.4 percent, respectively. The mean PCV of negative animals (28 percent) was significantly higher than the mean PCV of positive animals (22.3 percent) (P<0.001). There was an inverse association of PCV with the prevalence of trypanosomosis (P>0.05). The herd average PCV values of each site decreased with increasing proportion of the positive herds of that particular site. Of the diagnostic tests employed, the microhaematocrit buffy coat technique is relatively sensitive and it has an added advantage of indicating the general condition of the animal by haematocrit measurement. In view of the risk of trypanosomosis, a control intervention through the strategic application of appropriate trypanocidal drugs is recommended. A tsetse fly control scheme to reduce host-tsetse fly contact is equally as important as chemotherapy and chemoprophylaxis against trypanosomosis.

12414 Magona, J.W. & Mayende, J.S.P., 2002. Occurrence of concurrent trypanosomosis, theileriosis, anaplasmosis and helminthosis in Friesian, Zebu and Sahiwal cattle in Uganda. Onderstepoort Journal of Veterinary Research, 69 (2): 133-140.

Magona: Livestock Health Research Institute, PO Box 96, Tororo, Uganda.

An epidemiological investigation was conducted on farms in Tororo and Soroti districts of Uganda from January to February 2000 to determine the cause of reported persistent mortality of cattle. Blood and faecal material of 98 cattle comprising 33 Friesians, 58 Zebu and 7 Sahiwal were examined. Results revealed that seven (7.1 percent) cattle had trypanosome infection, mainly due to Trypanosoma vivax and T. brucei, 17 (17.3 percent) Fasciola infection, 28 (28.6 percent) gastrointestinal nematode infection, 33 (33.7 percent) Theileria sp. infection and 13 (13.3 percent) Anaplasma marginale infection. Mixed infections were detected in 30 percent, 20.6 percent and 43 percent of the Friesian, Zebu and Sahiwal cattle respectively. Anaemia (PCV<25) was detected in 24 percent, 19 percent and 14 percent of the Friesian, Zebu and Sahiwal cattle respectively. Persistent mortality of cattle on these farms could have been due to either single or mixed parasitic infections probably exacerbated by malnutrition.

12415 Magona, J.W., Mayende, J.S.P. & Walubengo, J., 2002. Comparative evaluation of the antibody-detection ELISA technique using microplates precoated with denatured crude antigens from Trypanosoma congolense or Trypanosoma vivax. Tropical Animal Health and Production, 34 (4): 295-308.

Magona: Livestock Health Research Institute, PO Box 96, Tororo, Uganda.

Two FAO/IAEA indirect enzyme-linked immunosorbent assays (ELISA), which use microplates precoated with denatured crude Trypanosoma congolense or Trypanosoma vivax antigen for detecting anti-trypanosomal antibodies in bovine sera, were evaluated for their sensitivity, specificity and positive and negative predictive values, using 320 Ugandan field samples (known negative sera, n = 80; known positive sera, n = 80; cattle herds where control of tsetse and trypanosomosis was practised, n = 80; and cattle herds where there was no such control, n = 80). Cut-off points of 30 percent and 25 percent positivity were determined for the T. congolense and T. vivax assays, respectively, using a modified ROC (receiver operating characteristic) analysis. The T. congolense assay had estimated diagnostic sensitivity and specificity of 63.7 percent and 57.5 percent, respectively, while the T. vivax assay had estimated diagnostic sensitivity and specificity of 81.3 percent and 81.3 percent, respectively. The two assays conducted in parallel had estimated diagnostic sensitivity and specificity of 82.5 percent and 88.7 percent, respectively. Using the sera from the cattle in the area with control (detected prevalence of trypanosomosis 0 percent), both the T. congolense and T. vivax assays had negative and positive predictive values of 100 percent and 0 percent, respectively. Using the sera from the cattle in the area without control (detected prevalence of trypanosomosis 15 percent), the T. congolense assay had negative and positive predictive values of 91 percent and 33 percent, respectively, and the T. vivax assay had negative and positive predictive values of 93 percent and 27 percent, respectively. The T. congolense assay was in fair agreement with the buffy coat technique (BCT) (k = 0.25), while the T. vivax assay was in substantial agreement with the BCT (k = 0.625), and both assays conducted in parallel were in substantial agreement with the BCT (k = 0.708). Both assays were found to be proficient and suitable for the diagnosis of bovine trypanosomosis, especially when used in parallel.

12416 Irungu, P., Nyamwaro, S.O. & Masiga, D.K., 2002. Financial implications of rearing sheep and goats under natural trypanosomosis challenge at Galana ranch, Kenya. Tropical Animal Health and Production, 34 (6): 503-513.

Masiga: Molecular Biology and Biotechnology Unit, ICIPE, PO Box 30772, Nairobi, Kenya. []

A study to compare the profitability of rearing sheep and goats under natural trypanosomosis challenge was carried out on Galana ranch in south-eastern Kenya between July 1996 and October 1997. Seventy-nine male weaner sheep and 79 male weaner goats were monitored monthly for weight changes and fortnightly for trypanosomosis. The animals of each species were divided into two groups. Group 1 was an untreated control, while group 2 was treated with isometamidium chloride (Samorin) at 0.5 mg/kg body weight every three months. In both groups, trypanosome infections were detected by microscopy and treated with diminazene aceturate (Veriben), at 3.5 mg/kg body weight, when the packed cell volume reached 17 percent or below. The profitability of each drug regime was expressed as the marginal revenue over the cost of trypanosomosis (MOT). There were greater losses occasioned by trypanosomosis in sheep than in goats. Animals of both species on chemoprophylaxis gave higher MOT values than those that received chemotherapy on diagnosis. However, the MOT values for the chemoprophylactic regime were higher for sheep than for goats, suggesting that the greater weight gain by sheep more than compensated for the higher cost of maintaining them under high trypanosomosis challenge. Thus, a Galana rancher would be better off keeping sheep rather than goats, other things being equal. The marginal revenue per dose of Samorin was lower than that of Veriben for both species, suggesting that strategic use of Samorin timed to precede the peak incidence of trypanosomosis might be a better option to raise the overall profitability in sheep and goats.

12417 Masiga, R.C. & Nyang'ao, J.M.N., 2001. Identification of trypanosome species from camel using polymerase chain reaction and procyclic transformation test. Journal of Camel Practice and Research, 8 (1): 17-22.

Masiga: KETRI, PO Box 362, Kikuyu, Kenya.

The identification of trypanosome species in field infections of camels is important if appropriate decisions on treatment and control are to be made. The development of specific DNA probes has greatly improved the accuracy of identification of trypanosomes. The polymerase chain reaction (PCR) is a more sensitive technique that requires as little as a single parasite for identification. This is particularly important in field infections where parasitaemia may be low. The objective of this study was to characterize trypanosomes from field infections of camels using PCR and the Procyclic Transformation Test (PTT). Due to the absence of a Trypanosoma brucei specific probe, the in vitro transformation was used to distinguish between T. brucei and T. evansi. Parasites were passaged in mice and DNA extracted from trypanosomes isolated from mouse blood. DNA primers specific to T. evansi type A, T. congolense, T. vivax and a satellite DNA sequence specific for the subgenus Trypanozoon were used to screen a total of 80 samples. Trypanosoma evansi was detected in 76 percent of the isolates confirming it to be the most important species causing trypanosomosis in camels in Kenya. Five per cent of the samples showed T. brucei alone and 15 percent evidenced mixed infections of T. congolense and T. brucei respectively. Of the 80 samples, 26 were tested for T. congolense, 8 (31 percent) samples had T. congolense either as a single or mixed infections.

12418 Michel, J.F., Dray, S., de La Rocque, S., Desquesnes, M., Solano, P., De Wispelaere, G. & Cuisance, D., 2002. Modelling bovine trypanosomosis spatial distribution by GIS in an agro-pastoral zone of Burkina Faso. Preventive Veterinary Medicine, 56 (1): 5-18.

Michel: CIRDES/CIRAD-EMVT, Bobo Dioulasso, Burkina Faso. []

Modelling of the spatial distribution of bovine trypanosomosis prevalence in Sideradougou district Burkina Faso was performed by using a combination of spatial and statistical analysis. Based on a comprehensive and geographically representative census of herds and farms in the area, more than 2 000 cattle were randomly chosen and their blood sampled during field survey. Data on livestock farming practices were recorded for each farm. All data were mapped within a GIS to generate new information on spatial constraints in the area. Surveys results were analysed and serological prevalence data were modelled using logistic regression. The model allowed identification and quantification of risk factors. In a second step the statistical model was used predictively on the entire farm population in the area. This method was successful in predicting the serological prevalence for each individual herd in the sample, from their livestock management patterns and spatial location. Predicted prevalences were represented within the GIS, taking daily movements of animals into account. Spatial distribution of prevalence would illustrate specific locations at risk from an epidemiological viewpoint. It gives evidence that the hydrological network and land occupation patterns in the savanna-type countryside are playing an important part when structuring a so-called "trypanosomosis space".

12419 Ogunsanmi, A., Taiwo, V. & Ohore, G., 2000. Application of antigen-detection enzyme immunoassay for the diagnosis of porcine Trypanosoma brucei infection. Veterinarski Archiv, 70 (5): 231-238.

Taiwo: Department of Wildlife and Fisheries Management, University of Ibadan, Ibadan, Nigeria.

The prevalence rate of Trypanosoma brucei infection in pigs was appraised by a monoclonal antibody-based antigen-detection enzyme immunoassay (antigen-ELISA). Blood samples were collected in the abattoir from pigs reared in the rain forest and derived savannah region of Nigeria under the traditional extensive management system. Blood samples were also collected from 50 exotic pigs reared on a commercial farm with fly-proof pens. These blood samples were analyzed for presence of trypanosomes and antigens in peripheral blood. Of 189 porcine blood samples 51 (27.0 percent) were positive for circulating antigens, whereas only four (2.1 percent) had demonstrable trypanosomes as revealed by the haematocrit centrifugation/buffy coat technique. When the 51 blood samples collected in EDTA tube corresponding to those sera that were positive for T. brucei antigens were subinoculated into mice, 46 (90.1 percent) of the mice became infected. Demonstration of trypanosomes in the infected mice is supportive proof that the parasites were residing in the infected hosts. Samples collected from 50 exotic pigs in fly-proof pens were all antigen-ELISA negative. In addition, none of the corresponding 50 control blood samples had demonstrable trypanosomes by the buffy coat method, nor do they show detectable parasites after subinoculation into mice. Thus, antigen-ELISA appeared to be a better and more useful tool for mass sero-epidemiological survey of porcine T. brucei infection as compared with the buffy coat technique.

12420 Robinson, T.P., Harris, R.S., Hopkins, J.S. & Williams, B.G., 2002. An example of decision support for trypanoso miasis control using a geographical information system in eastern Zambia. International Journal of Geographical Information Science, 16 (4): 345-360.

Robinson: ILRI, PO Box 30709, Nairobi, Kenya.

In many African countries where both Government resources and donor aid for the control of tsetse-transmitted trypanosomiasis are declining, there is an increasing need to identify areas where intervention is most likely to be technically, economically, socially and environmentally sustainable. Activities then can be focused so that the maximumbenefits are obtained from limited resources. We describe a decision-support framework based on a geographical information system to identify areas of high priority for the control of tsetse and trypanosomiasis in the common fly belt of eastern Zambia. Digital coverages were generated for six environmental variables: (1) cattle density, (2) human density, (3) land designation, (4) relative arable potential, (5) crop-use intensity and (6) proximity to existing control operations. The distribution of tsetse in the area was predicted using a multivariate (maximum likelihood) analysis of areas of known presence and absence and a series of environmental data. Experienced Zambian veterinarians and biologists working in the region established criteria weights for the input variables and the data were integrated in a geographical information system (GIS), using weighted linear combinations to prioritize areas for trypanosomiasis control. The results of this exercise and estimates of the errors involved are discussed.

12421 Sharma, S.P., Losho, T.C., Malau, M., Mangate, K.G., Linchwe, K.B., Amanfu, W. & Motsu, T.K., 2001. The resurgence of trypanosomosis in Botswana. Journal of the South African Veterinary Association, 72 (4): 232-234.

Sharma: National Veterinary Laboratory, Private Bag 0035, Gaberone, Botswana.

In view of the occurrence of several confirmed clinical cases of nagana and reports of heavy bovine mortality, a parasitological survey was conducted to determine the prevalence of trypanosome infection in cattle in Maun and Shakawe areas of Ngamiland district. Wet blood films, buffy coat and Giernsa-stained thick and thin blood smears were used to detect trypanosomes in animals. Overall, trypanosome infection rate was 15.98 percent, with 5.94 percent and 27.29 percent in Maun and Shakawe respectively. The urgent need to combat trypanosomosis in Ngamiland, particularly in the Shakawe area, is highlighted, and a three-phase integrated tsetse control strategy for this disease problem is discussed.

(b) Pathology and immunology

[See also 25: no. 12426]

12422 Bengaly, Z., Sidibe, I., Ganaba, R., Desquesnes, M., Boly, H. & Sawadogo, L., 2002. Comparative pathogenicity of three genetically distinct types of Trypanosoma congolense in cattle: clinical observations and haematological changes. Veterinary Parasitology, 108 (1): 1-19.

Bengaly: CIRDES, 01 BP 454, Bobo-Dioulasso 01, Burkina Faso. []

The pathology of African bovine trypanosomosis was compared in Zebu cattle subcutaneously inoculated with three clones of trypanosomes corresponding to the three genetically distinct types of Trypanosoma congolense; savanna-type, west African riverine/forest-type and kilifi-type. All inoculated animals became parasitaemic between seven and eleven days post-infection (dpi). The savanna-type showed consistently higher levels of parasitaemia, and lower packed red cell volume percentages and leukocyte counts than the other two types. The syndrome was also more severe in the savanna-type and led inexorably to death between 29 and 54 dpi while animals with the forest or the kilifi-types recovered from earlier symptoms and haematological alterations after three months of infection. By the end of the experiment, the animals self-cured from the forest-type infection and the kilifi-type passed under control. The results of the present study indicated clear difference in pathogenicity between the three types of T. congolense; the savanna-type was virulent while the forest-type was of low pathogenicity and the kilifi-type was non-pathogenic.

12423 Masiga, D.K., Okech, G., Irungu, P., Ouma, J., Wekesa, S., Ouma, B., Guya, S.O. & Ndung'u, J.M., 2002. Growth and mortality in sheep and goats under high tsetse challenge in Kenya. Tropical Animal Health and Production, 34 (6): 489-501.

Masiga: Molecular Biology and Biotechnology Unit, ICIPE, PO Box 30772, Nairobi, Kenya. []

Trypanosomosis is a major impediment to livestock production and economic development in those areas of Africa where it is endemic. Although small ruminants appear to perform better than cattle in various agro-ecological zones, the importance of trypanosomosis has not been extensively investigated in these livestock. This study was designed to investigate the prevalence of trypanosomosis in sheep and goats in an endemic area and to evaluate the performance of different breeds under high tsetse challenge and the potential role of chemoprophylaxis in the control of the disease. The results showed that tsetse flies feed readily on small ruminants, and that these animals are susceptible to trypanosomosis. The Small East African goats acquired fewer infections than the Black Head Persian and Dorper sheep used in the study. In both sheep and goats, chemoprophylaxis with isometamidium chloride (Samorin, Rhone Merieux, Annecy, France) was protective, resulting in fewer infections and higher body weight gain. Trypanosomosis caused anaemia in both sheep and goats, and animals whose PCV fell below 15 percent rarely recovered, even with trypanocidal drug treatment. The peak transmission period was between one and three months after the peak tsetse fly density, which raises the possibility of effective strategic prophylaxis.

12424 Mattioli, R.C. & Mehlitz, D., 2001. Vector-borne haemoparasitic complexes: a major potential disease risk factor impairing cattle health and production in tsetse-infested areas of West Africa. Journal of Agriculture and Environment for International Development, 95 (2-3): 237-244.

Animal Production and Health Division, Food and Agriculture Organization of the United Nations, FAO, Viale delle Terme di Caracalla, 00100 Rome, Italy.

Repeated trypanosome infections render both trypanosusceptible and trypanotolerant cattle more susceptible to tick attack and, consequently, to increased challenges of tick-borne micro-organism species and respective infective inoculated doses. In such a situation, enzootic stability to tick-transmitted infections may vanish. Recently, three pathological syndromes, responsible for high mortality, have been reported in N'Dama cattle populations living in sub-humid and humid zones of Guinea and Senegal infested by tsetse fly and ticks. These syndromes are termed, in vernacular language, Red and Black Woula and Dasso in Guinea and Senegal, respectively. "Red" and "Black" denominations of the Woula syndrome appear to be related, respectively, to haemoglobinuria (Red) and cyanotic aspect (Black) of apparent mucous membranes in sick animals. Woula per se signifies, in local language, "unpopulated remote area located far off in the savannah". Dasso designates a not well-defined animal pathological status. We note that, in the case of Red and Black Woula, the description of a delineated geographic area is included by the indigenous people in the definition of these two syndromes. This would indicate that the pathogens involved are confined to defined zones. Preliminary information suggests these syndromes are caused by a common infective haemoparasitic complex composed of trypanosomes and tick-borne anaplasmosis and/or babesiosis. Perspective investigations are needed to obtain epidemiological data to identify the micro-organisms involved, density and seasonality of potential vectors and to assess the impact of the pathological challenge in order to set up, if necessary, adequate and economically profitable control measures.

12425 Ndoutamia, G., Mbakasse, R.N., Brahim, A. & Khadidja, A., 2002. Influence de la trypanosomose à T. congolense sur les paramètres hématologiques, minéraux et protéo-énergétiques chez les chèvres sahéliennes du Tchad. [Influence of Trypanosoma congolense infection on some haematological and serum biochemical parameters in sahelian goats.] Revue de Médecine Vétérinaire, 153 (6): 395-400.

Ndoutamia: Laboratoire de Recherches Vétérinaires et Zootechniques de Farcha, B.P. 433, Ndjaména, Tchad. []

Forty Sahelian goats whose haemoglobin types had been determined, were experimentally infected, each one with 106 trypanosomes (Trypanosoma congolense IL 1180 stock savanna type). Clinical signs, body weight, haematological and serum biochemical parameters were recorded over six months. The Sahelian goats were highly susceptible to the infection. They developed an acute disease which was lethal within four weeks. The prepatent period was approximately seven days. During the acute phase of the disease, the animals displayed lack of appetite, pale ocular membranes, watering eyes, staggering movements and occasional diarrhoea. The haematocrit dropped from 38.68 percent to 25.72 percent and often reached the critical point of 15 percent. At that threshold the animals were unable to stand up and died unless a trypanocidal treatment was applied. The T. congolense trypanosomiasis evolution was associated at different levels with significant changes in haematological and serum biochemical parameters. The disease was mainly characterized by the decrease of the red blood cells, haemoglobin, albumin, cholesterol, glycaemia and the rise in level of the white blood cells, serum iron, calcium, bilirubines and urea. The most vulnerable enzymes were the transaminases the activity of which varied considerably throughout the experimental period.

12426 Taiwo, V.O., Adejinmi, J.O. & Oluwaniyi, J.O., 2002. Non-immune control of trypanosomosis: In vitro oxidative burst of PMA- and trypanosome-stimulated neutrophils of Boran and N'Dama cattle. Onderstepoort Journal of Veterinary Research, 69 (2): 155-161.

Taiwo: Department of Veterinary Pathology, University of Ibadan, Ibadan, Nigeria.

An in vitro assay that measures the generation of superoxide anions (02-) was used to assess the level of oxidative burst of phorbol myristate acetate (PMA)- and trypanosome-stimulated neutrophils isolated from healthy Boran and N'Dama cattle, and those infected with Trypanosoma congolense. PMA stimulation of healthy bovine neutrophils resulted in between 300-400 percent increase in 02- generation. Neutrophils of Boran cattle exhibited slightly (but not significantly) higher 02- generation capacity than those of the N'Dama breed. In vitro stimulation by trypanosomes of neutrophils isolated from Trypanosoma congolense-infected cattle caused significant increases in 02- generation, especially on days 14, 28 and 42 post-infection, in both breeds of cattle. No significant differences were observed in 02- generation capacity of the neutrophils of either breed of infected cattle throughout the period of assay. The results of this study have shown that PMA and trypanosomes do cause an enhanced in vitro oxidative burst, hence trypanosome phagocytosis and killing activity of neutrophils. Neutrophils have been shown to play very significant roles in parasite clearance, hence reduction of trypanosome parasitaemia. The rates of both in vitro generation of 02- and trypanosome phagocytosis over time did not differ significantly between Boran and N'Dama breeds of cattle, even during T. congolense infection in this study. Hence, it may be inferred that sustained and higher parasitaemia, more pronounced neutropenia, inadequate bone marrow response and less effective trypanosome-specific immune response, rather than defective neutrophil trypanosome destruction, may be the problem of trypanosusceptible cattle breeds.

(c) Trypanotolerance

[See also 25: no. 12434]

12427 Faye, D., Osaer, S., Goossens, B., Van Winghem, J., Dorny, P., Lejon, V., Losson, B. & Geerts, S., 2002. Susceptibility of trypanotolerant West African Dwarf goats and F1 crosses with the susceptible Sahelian breed to experimental Trypanosoma congolense infection and interactions with helminth infections and different levels of diet. Veterinary Parasitology, 108 (2): 117-136.

Faye: ITC, PMB 14, Banjul, The Gambia. []

Forty pure West African Dwarf (WAD) goats and 35 of its F1 crosses with the Sahelian breed were used in a multifactorial experimental design to evaluate the effects of an experimental Trypanosoma congolense infection and interactions with natural helminth infections and different levels of diet on health and productivity of these two breeds. Trypanosome infection caused a severe drop in packed cell volume (PCV), but this was not significantly affected by breed. Neither deworming nor diet had any effect on the course of anaemia after trypanosome infection. The mean score of parasitaemia tended to be higher in crossbreeds than in WAD goats although this was not significant (P > 0.05). Similarly, the antibody response to trypanosome infection was not significantly different between breeds. Parasitaemia level was significantly influenced by the level of diet with the group under high supplementation having a higher mean parasitaemia score than the group under low supplementation. Weight loss due to trypanosome infection tended to be greater in crossbreeds than in WAD goats (P > 0.05). During this study, there was no difference in mean helminth egg output between crossbred and WAD goats. However, between weeks 4 and 10 after trypanosome infection (corresponding to a period of heavy rainfall and highly infective pastures), the mean egg output was higher in the crossbreeds. The immunosuppressive effect of trypanosome infections was revealed by a lower antibody response to Haemonchus contortus in infected animals compared with the uninfected controls. Trypanosome infection tended to increase strongyle egg output. This study did not reveal any superior trypanotolerance of WAD goats compared with crossbreeds.

12428 Ogunsanmi, A., Taiwo, V., Onawumi, B., Mbagwu, H. & Okoronkwo, C., 2001. Correlation of physiological plasma lipid levels with resistance of cattle to trypanosomosis. Veterinarski Arhiv, 70 (5): 251-257.

Taiwo: Department of Wildlife and Fisheries Management, University of Ibadan, Ibadan, Nigeria.

Haematological values and indices as well as plasma lipids (cholesterol and triglyceride) levels were studied in trypanotolerant N'Dama and trypanosusceptible White Fulani (Zebu) cattle raised in the same environment in order to determine the probable role of plasma lipids levels in the phenomenon of trypanotolerance in tropical cattle. The haematological parameters and indices, such as PCV, Hb concentration, RBC, WBC counts, MCV and MCH, showed no significant differences (P>0.05) between the two cattle breeds or sex. N'Dama cattle had significantly lower levels of plasma cholesterol (P<0.05) and triglycerides (P<0.01) than Fulani cattle. Male N'Dama cattle had significantly higher plasma cholesterol levels than females. While no significant gender difference (P>0.05) was observed in plasma triglyceride levels in N'Dama cattle, a significantly higher (P<0.012) plasma triglyceride level was recorded in female White Fulani cattle than in their male counterparts. The findings in this study suggest a possible correlation between plasma lipid levels and trypanotolerance or susceptibility between N'Dama and White Fulani cattle. The roles of plasma lipids in trypanosome growth and differentiation, as well as in the pathology of the disease in the host, are discussed.

12429 Tano, K., Kamuanga, M., Faminow, M.D. & Swallow B.M., 2001. Adoption and demand for trypanotolerant cattle in the sub-humid zone of West Africa. Journal of Agriculture and Environment for International Development, 95 (2/3): 213-236.

Tano: Centre Ivoirien de Recherches Economique et Sociales (CIRES), Université d'Abidjan-Cocody, 08 BP 1295 Abidjan 08, Côte d'Ivoire.

Baoulé is one of several breeds of West African Shorthorn cattle (Bos taurus brachycheros) that are trypanotolerant and thus can survive and produce in areas of low to moderate tsetse (Glossina spp.) challenge without the aid of drugs. In southern Burkina Faso, Baoulé are raised under different management systems along with trypanosusceptible Zebu (Bos indicus) and crossbred Méré cattle. A trend among livestock farmers towards large Zebu-type cattle is perceptible, raising concerns about the risk of extinction of Baoulé. A study was undertaken in two areas of southern Burkina Faso (Pays Lobi and Kourouma) to evaluate the main factors affecting adoption and utilization of Baoulé and to determine the prospects for its conservation. Emphasis was placed on the rôle of farmers' subjective perceptions of the traits of Baoulé relative to other breeds. The results of a Logit model indicate that indigenous farmers and those generally involved in subsistence production systems are more likely to keep Baoulé cattle in their herds. In contrast, the probability is very low for migrants and mixed crop-livestock farmers to raise this breed. Farmers' high rating of the overall desirability of Baoulé increases the probability of adoption while a high rating of Zebu's fitness to traction negatively affects the probability of adoption of Baoulé. The strategy for in situ breed conservation should be targeted to traditional farmers of Pays Lobi given their high probability of adopting Baoulé and the high discretion they exercise over the choice of this breed as shown by the large proportion of Baoulé cattle purchased and introduced into their herds.

(d) Treatment

[See also 25: no. 12439]

12430 Delespaux, V., Geerts, S., Brandt, J., Elyn, R. & Eisler, M.C., 2002. Monitoring the correct use of isometamidium by farmers and veterinary assistants in Eastern Province of Zambia using the isometamidium-ELISA. Veterinary Parasitology, 110 (1-2): 117-122.

Delespaux: Institute of Tropical Medicine, Nationalestraat 155, B-2000 Antwerp, Belgium. []

A survey to monitor the use of trypanocidal drugs by cattle breeders was conducted in Zambia. Use was made of a questionnaire and of the isometamidium-ELISA technique. One hundred and twenty two farmers and 50 veterinary assistants were interviewed. The isometamidium-ELISA was used to monitor the isometamidium serum concentration in 72 cattle, one week after unsupervised treatment by 56 farmers and 16 veterinary assistants. Although there was no clear indication of underestimation of the weight of the animals and although farmers had adequate knowledge of the correct usage of isometamidium, the results suggest frequent underdosing when considering isometamidium serum concentrations one week after treatment. In 76 percent of the cases, the expected protection period was equal or shorter than 28 days and equal or shorter than 33 days in 90 percent of the treated cattle.

12431 Olila, D., McDermott, J.J., Eisler, M.C., Mitema, E.S., Patzelt, R.J., Clausen, P.H., Poetzsch, C.J., Zessin, K.H., Mehlitz, D. & Peregrine, A.S., 2002. Drug sensitivity of trypanosome populations from cattle in a peri-urban dairy production system in Uganda. Acta Tropica, 84 (1): 19-30.

Peregrine: Department of Pathobiology, Ontario Veterinary College, University of Guelph, Guelph ON, N1G 2W1, Canada.

Cattle from 50 farms in Mukono County, Uganda, were monitored for trypanosomes every second month over an 18-month period (1995-1996) by mini-anion exchange chromatography and haematocrit centrifugation techniques. Eighteen trypanosome isolates collected from cattle during this period were characterized in cattle, goats and mice for their sensitivity to homidium, isometamidium and diminazene; ten of the isolates were selected randomly, eight were from animals that had the highest serum isometamidium concentrations at the time the isolates were collected. All the isolates contained only Trypanosoma brucei and/or T. vivax. In naive Boran (Bos indicus) cattle the isolates exhibited low pathogenicity and were sensitive to diminazene aceturate at 3.5 mg/kg body weight (bw) and isometamidium chloride at 0.5 mg/kg bw. In goats, five of eight isolates were highly pathogenic, producing clinical signs indicative of central nervous system involvement within 60 days of infection; all such isolates contained T. brucei. However, all eight populations were sensitive in goats to diminazene aceturate at 3.5 mg/kg bw. In contrast, four populations were refractory to treatment with isometamidium chloride at 0.5 mg/kg bw in at least one out of three goats each. Furthermore, five populations were refractory to treatment with homidium chloride at 1.0 mg/kg bw in a minimum of two out of three goats each. In mice, the 50 percent curative dose values for 11 Mukono isolates that contained T. brucei ranged from 0.30 to 1.89 mg/kg bw for diminazene aceturate, from 0.02 to 0.17 mg/kg bw for isometamidium chloride and from 0.90 to 4.57 mg/kg bw for homidium chloride. Thus, by comparison with reference drug-sensitive populations, all the stabilates were highly sensitive to diminazene and isometamidium, while some expressed low levels of resistance to homidium.

7. Experimental trypanosomiasis

(a) Diagnostics

12432 Desquesnes, M. & Dávila, A.M.R., 2002. Applications of PCR-based tools for detection and identification of animal trypanosomes: a review and perspectives. Veterinary Parasitology, 109 (3-4): 213-231.

Desquesnes: CIRAD-EMVT/CIRDES, 01 BP, Bobo-Dioulasso, Burkina Faso. []

This paper aims to review the applications of the polymerase chain reaction (PCR) for the detection and identification of trypanosomes in animals. The diagnosis of trypanosomes, initially based on microscopic observations and the host range of the parasites, has been improved, since the 1980s, by DNA-based identification. These diagnostic techniques evolved successively through DNA probing, PCR associated to DNA probing, and currently to PCR alone. Several DNA sequences have been investigated as possible targets for diagnosis, especially multi-copy genes such as mini-exon, kinetoplastid mini-circles, etc., but the most favoured target is the nuclear satellite DNA of mini-chromosomes, which presents the advantages, and the drawbacks, of highly repetitive short sequences (120-600bp). Several levels of specificity have been achieved from sub-genus to species, sub-species and even types. Random priming of trypanosome DNA has even allowed "isolate specific" identification. Other work based on microsatellite sequences has provided markers for population genetic studies. For regular diagnosis, the sensitivity of PCR has increased with the advancement of technologies for sample preparation, to reach a level of 1 trypanosome/ml of blood, which has brought to field samples a sensitivity two to three times higher than that obtained from microscopic observation of the buffy coat. Similarly, PCR has allowed an increase in the specificity and sensitivity of diagnosis in vectors such as tsetse flies. However, because of the diversity of Trypanosoma species potentially present in a single host, PCR diagnosis carried out on host material requires several PCR reactions; for example, in cattle, up to five reactions per sample may be required. Research is now focusing on a diagnosis based on the amplification of the internal transcribed spacer-1 (ITS-1) of ribosomal DNA which presents the advantages of being a multi-copy locus (100-200), having a small size (300-800 bp), which varies from one taxon to another but is conserved in size in a given taxon. This may lead to the development of a multi-species-specific diagnostic protocol using a single PCR. By reducing the cost of the PCR diagnosis, this technique would allow a greater number of field samples to be tested in epidemiological studies and/or would increase the variety of Trypanosoma species that could be detected. Further investigations are required to develop and optimize multi-species-specific diagnostic tools for trypanosomes, which could also serve as a model for such tools in other pathogens.

12433 Radwanska, M., Magez, S., Perry-O'Keefe, H., Stender, H., Coull, J., Sternberg, J.M., Büscher, P. & Hyldig-Nielsen, J.J., 2002. Direct detection and identification of African trypanosomes by fluorescence in situ hybridization with peptide nucleic acid probes. Journal of Clinical Microbiology, 40 (11): 4295-4297.

Radwanska: Department of Immunology, Groote Schuur Hospital, Old Main Building H47, Observatory 7925, Cape Town, South Africa. []

We have developed a rapid and easy-to-perform fluorescence in situ hybridization test that allows specific identification of trypanosomes from the subgenus Trypanozoon, using peptide nucleic acid probes. Probes were designed to target subgenus-specific sequences on the multiple-copy 18S rRNA, greatly facilitating the detection of a single trypanosome.

(b) Pathology and immunology

[See also 25: no. 12428]

12434 Noël, W., Gh, G.H., Raes, G., Namangala, B., Daems, I., Brys, L., Brombacher, F., De Baetselier, P. & Beschin, A., 2002. Infection stage-dependent modulation of macrophage activation in Trypanosoma congolense-resistant and -susceptible mice. Infection and Immunity, 70 (11): 6180-6187.

Beschin: Cellular Immunology Unit, Flemish Interuniversity Institute for Biotechnology, VIB-VUB, Paardenstraat 65, B-1640 St-Genesius-Rode, Belgium. []

The contribution of cytokines and chemokines to resistance and susceptibility to African trypanosomiasis remains controversial. In the present study, the levels of type I and type II cytokines and of the MCP-1 chemokine were compared during the early and late stages of Trypanosoma congolense infection in susceptible BALB/c and resistant C57BL/6 mice. Moreover, the status of macrophage activation was compared in these animals by analyzing the inducible nitric oxide synthase-arginase balance, tumor necrosis factor secretion, and expression of the FIZZ1 and YM genes. Data show that changing from a predominant type I cytokine environment in the early stage of infection to a predominant type II cytokine environment and an enhanced MCP-1 secretion in the late stage of infection correlates with resistance to T. congolense. Concomitantly, macrophage activation evolves from a classical to a predominant alternative phenotype. We further confirmed that the simultaneous occurrence of type I/type II cytokines in the early stage of infection in susceptible BALB/c mice, reflected by the presence of macrophages exhibiting a mixed classical/alternative activation phenotype, is associated with uncontrolled parasite growth and early death. Interleukin-4 (IL-4) and IL-13 signalling did not influence the susceptibility of BALB/c mice to T. congolense infection and interestingly were not the main trigger to alternative macrophage activation. In T. congolense-resistant C57BL/6 mice, our results corroborated the induction of FIZZ1 and YM gene expressions with the alternative pathway of macrophage activation. In susceptible BALB/c mice, however, YM but not FIZZ1 induction reflected the emergence of alternatively activated macrophages. Hence, the FIZZ1 and YM genes may be useful markers to discriminate between distinct populations of alternatively activated macrophages.

12435 Ojok, L., Kaeufer-Weiss, I. & Weiss, E., 2002. Distribution of Trypanosoma congolense in infected multimammate rats (Mastomys coucha): light and electron microscopical studies. Veterinary Parasitology, 105 (4): 327-336.

Ojok: Department of Veterinary Pathology, Faculty of Veterinary Medicine, Makerere University, PO Box 7062, Kampala, Uganda. []

In an attempt to determine whether Trypanosoma congolense occurs both within and outside the blood vessels in an infected animal host, multimammate rats (Mastomys coucha) were infected with T. congolense and samples from spleen, lymph nodes, bone marrow, liver, kidney, lungs, brain, heart, intestines, ovaries and testes were collected. The tissue samples were fixed and processed for light and electron microscopical examination. In all the tissues examined, trypanosomes were found only within the lumen of large and small blood vessels, capillaries and sinuses. It is concluded that following entry into the blood circulation after intra-peritoneal infection of M. coucha, T. congolense remains restricted to the bloodstream.

12436 Olaniyi, M.O., Taiwo, V.O. & Ogunsanmi, A.O., 2001. Haematology and dynamics of erythrocyte membrane sialic acid concentration during experimental Trypanosoma congolense and T. brucei infection of sheep. Journal of Applied Animal Research, 20 (1): 57-64.

Taiwo: Department of Veterinary Pathology, University of Ibadan, Ibadan, Nigeria.

Haematological changes and the dynamics of erythrocyte membrane sialic acid concentration were studied in sheep experimentally infected with Trypanosoma congolense (Binchi Bassa strain) and T. brucei (Lafia strain). Both species of trypanosomes caused varying degrees of pathogenicity. The anaemia was more severe (P <0.05) in T. brucei than in T. congolense infected sheep. There was significant (P <0.05) reduction in erythrocyte membrane surface sialic acid concentration with progression of infection in both T. congolense and T. brucei infected sheep.

(c) Chemotherapeutics

12437 Ali, H., König, G.M., Khalid, S.A., Wright, A.D. & Kaminsky, R., 2002. Evaluation of selected Sudanese medicinal plants for their in vitro activity against hemoflagellates, selected bacteria, HIV-1-T and tyrosine kinase inhibitory, and for cytotoxicity. Journal of Ethnopharmacology, 83 (3): 219-228.

König: Institut für Pharmazeutische Biologie, University of Bonn, Nussallee 6, D-53115 Bonn, Germany. []

Ethnobotanical investigations led to the selection of 19 plant species, used traditionally in Sudan against malaria and other similar tropical diseases, for further studies. Pamianthe peruviana (Amaryllidaceae) exhibited significant activity against a chloroquine-resistant Plasmodium falciparum strain (K1) and a chloroquine-sensitive strain (NF54) with IC50 values of 0.6 and 1.1 mg/ml, respectively. Additionally, P. peruviana showed considerable activities against Trypanosoma brucei rhodesiense (IC50 1.5 mg/ml) and T. cruzi (IC50 11.8 mg/ml). The antiplasmodial activity of the different extracts of Salvadora persica (Salvadoraceae) against P. falciparum NF54 strain were found to be 0.6 mg/ml (stems) and 0.7 mg/ml (leaves). Extracts of different parts of Combretum hartmannianum (Combretaceae) possessed significant activity against the chloroquine-sensitive P. falciparum strain (NF54) with IC50 values of 0.2 mg/ml (bark), 0.4 mg/ml (stem) and 4.3 mg/ml (leaves). Most interestingly, the extracts of the leaves of C. hartmannianum totally inhibited the enzyme HIV-1 reverse transcriptase (HIV-1 RT) at a concentration of 66 mg/ml. A comparably strong activity against p56lck tyrosine kinase was also seen for this extract.

12438 D'Silva, C. & Daunes, S., 2002. The therapeutic potential of inhibitors of the trypanothione cycle [T. brucei]. Expert Opinion on Investigational Drugs, 11 (2): 217-231.

D'Silva: Department of Chemistry and Materials, The Manchester Metropolitan University, John Dalton Building, Chester Street. Manchester M1 5GD, UK.

There is an urgent need for new drugs in the treatment of human African trypanosomiasis, Chagas' disease and leishmaniasis. This article provides an overview of current drugs, their formulations and their deficiencies. Targets for the design of new drugs and a rationale provided for targeting enzymes of the trypanothione cycle are described. Biochemical aspects of the cycle and the currently investigated target trypanothione reductase are discussed as are the several classes of inhibitors and their in vitro potencies. Evidence is provided for considering the tryparedoxins as a new target for antiprotozoal chemotherapy and a summary of glutathione-based inhibitors with significant in vitro activity is presented.

12439 Karanja, W.M., Mdachi, R.E. & Murilla, G.A., 2002. A competitive enzyme-linked immunosorbent assay for diminazene. Acta Tropica, 84 (2): 75-81.

Karanja: KETRI, PO Box 362, Kikuyu, Kenya.

Diminazene aceturate has remained a very important therapeutic drug for trypanosomosis in cattle, sheep and goats since its introduction into the market in 1955. Despite its continued use, the methods available for its detection in body fluids are lengthy and inefficient for routine monitoring of drug levels in treated animals. A competitive enzyme linked immunosorbent assay (ELISA) has now been developed and optimized for the detection of diminazene in bovine serum. In the assay, diminazene in the test samples and that in a newly developed diminazene-horseradish peroxidase conjugate compete for antibodies to diminazene raised in rabbits and immobilized on a microtitre plate. Tetramethylbenzidine-hydrogen peroxide (TMB/H2O2) is used as chromogen-substrate system. The assay has a detection limit of 0.8 ng/ml of serum with a high specificity for diminazene. Cross-reactivity with either homidium bromide and quinapyramine sulphate/chloride of 0.0004 percent is negligible while that with isometamidium chloride is 0.71 percent. The assay was able to detect diminazene levels in normal Boran steers for at least two weeks after intramuscular injection with the drug at a dose of 3.5 mg/kg bw. The assay will be useful in monitoring diminazene use, and development of resistance in trypanosomosis endemic areas.

12440 Marasco, C.J. Jr., Kramer, D.L., Miller, J., Porter, C.W., Bacchi, C.J., Rattendi, D., Kucera, L., Iyer, N., Bernacki, R., Pera, P. & Sufrin, J.R., 2002. Synthesis and evaluation of analogues of 5'-([(Z)-4-amino-2-butenyl]methylamino)-5'-deoxyadenosine as inhibitors of tumor cell growth, trypanosomal growth, and HIV-1 infectivity. [T. brucei] Journal of Medicinal Chemistry, 45 (23): 5112-5122.

Sufrin: Department of Pharmacology and Therapeutics, Grace Cancer Drug Center, Roswell Park Cancer Institute, Buffalo, New York 14263 USA. []

8. Trypanosome research

(a) Cultivation of trypanosomes

(b) Taxonomy, characterization of isolates

12441 Gibson, W., 2002. Will the real Trypanosoma brucei rhodesiense please step forward? Trends in Parasitology, 18 (11): 486-490.

Gibson: School of Biological Sciences, University of Bristol, Bristol, BS8 1UG, UK. []

The sleeping sickness trypanosomes Trypanosoma brucei rhodesiense and T. brucei gambiense are morphologically indistinguishable from each other and from T. brucei brucei, which does not infect humans. The relationships between these three subspecies have been controversial. Several years ago, the characterization of T. brucei gambiense was reviewed in an attempt to clarify and draw together the results, and to put them in the context of the biology of the organism. The discovery of a gene associated with human-serum resistance in T. brucei rhodesiense and the consequent reappraisal of the identity of this trypanosome prompt this companion article.

12442 Momen, H., 2002. Molecular taxonomy of trypanosomatids: Some problems and pitfalls. Archives of Medical Research, 33 (4): 413-415.

Momen: editor, Bulletin of the World Health Organization, EIP/IMD, WHO, 20 Avenue Appia, 1211 Geneva, 27, Switzerland. []

Trypanosomatids appear to have attracted the particular attention of taxonomists and a wealth of data from studies using a variety of techniques is available. There are, however, some potential pitfalls in such studies. A general problem in the taxonomy of trypanosomatids is that only a small amount of the true diversity is reflected in the limited number of isolates identified and studied from this family. An associated problem is that of confusion over the identity of the organisms. Other concerns include the problems of long branch attractions and mutational saturation, the loss of phylogenetic signal from the accumulation of overlapping mutations, and the fact that gene phylogeny cannot be equated with organism phylogeny and that organisms are more than just the sum of their genes. Additional complications can occur due to numerous cases of horizontal gene transfer between organisms. The use of a large sample of recent isolates from the field is also important so that the true diversity of these organisms is reflected in these studies, and bias due to selection, contamination, and misidentification when isolates have been maintained for long periods in culture is eliminated.

12443 Van der Heyden, N. & Docampo, R., 2002. Significant differences between procyclic and bloodstream forms of Trypanosoma brucei in the maintenance of their plasma membrane potential. Journal of Eukaryotic Microbiology, 49 (5): 407-413.

Docampo: Laboratory of Molecular Parasitology, Department of Pathobiology, University of Illinois at Urbana-Champaign, 2001 S. Lincoln Avenue, Urban IL 61802, USA. []

(c) Life cycle, morphology, biochemical and molecular studies

[See also 25: no. 12395]

12444 Boibessot, I., Turner, C.M.R., Watson, D.G., Goldie, E., Connel, G., McIntosh, A., Grant, M.H. & Skellern, G.G., 2002. Metabolism and distribution of phenanthridine trypanocides in Trypanosoma brucei. Acta Tropica, 84 (3): 219-228.

Grant: Bioengineering Unit, University of Strathclyde, 106 Rottenrow East, Wolfson Centre, Glasgow G4 0NW, UK. []

12445 Berriman, M., Hall, N., Sheader, K., Bringaud, F.D., Tiwari, B., Isobe, T., Bowman, S., Corton, C., Clark, L., Cross, G.A.M., Hoek, M., Zanders, T., Berberof, M., Borst, P. & Rudenko, G., 2002. The architecture of variant surface glycoprotein gene expression sites in Trypanosoma brucei. Molecular and Biochemical Parasitology, 122 (2): 131-140.

Rudenko: The Peter Medawar Building for Pathogen Research, University of Oxford, Oxford OX1 3SY, UK. []

12446 Bochud-Allemann, N. & Schneider, A., 2002. Mitochondrial substrate level phosphorylation is essential for growth of procyclic Trypanosoma brucei. Journal of Biological Chemistry, 277 (36): 32849-32854.

Schneider: Department of Biology/Zoology, University of Fribourg, Chemin du Musée 10, CH-1700 Fribourg, Switzerland. []

12447 Bringaud, F., Biteau, N., Melville, S.E., Hez, S., El-Sayed, N.M., Leech, V., Berriman, M., Hall, N., Donelson, J.E. & Baltz, T., 2002. A new, expressed multigene family containing a hot spot for insertion of retroelements is associated with polymorphic subtelomeric regions of Trypanosoma brucei. Eukaryotic Cell, 1 (1): 137-151.

Bringaud: Laboratoire de Parasitologie Moléculaire, Université Victor Segalen Bordeaux II, UMR-5016 CNRS, 33076 Bordeaux cedex, France.

12448 Bringaud, F., Biteau, N., Melville, S.E., Hez, S., El-Sayed, N.M., Leech, V., Berriman, M., Hall, N., Donelson, J.E. & Baltz, T., 2002. A new, expressed multigene family containing a hot spot for insertion of retroelements is associated with polymorphic subtelomeric regions of Trypanosoma brucei (vol 1, pg 137, 2002). (Correction) Eukaryotic Cell, 1 (2): 315.

Bringaud: Laboratoire de Parasitologie Moléculaire, Université Victor Segalen Bordeaux II, UMR-5016 CNRS, 33076 Bordeaux cedex, France.

12449 Breitling, R., Klingner, S., Callewaert, N., Pietrucha, R., Geyer, A., Ehrlich, G., Hartung, R., Müller, A., Contreras, R., Beverley, S.M. & Alexandrov, K., 2002. Non-pathogenic trypanosomatid protozoa as a platform for protein research and production. Protein Expression and Purification, 25 (2): 209-218.

Alexandrov: Department of Physical Biochemistry, Max Planck Institute for Molecular Physiology, Otto Hahn Strasse 11, 44227 Dortmund, Germany. []

12450 Buckner, F.S., Kateete, D.P., Lubega, G.W., Van Voorhis, W.C. & Yokoyama, K., 2002. Trypanosoma brucei prenylated-protein carboxyl methyltransferase prefers farnesylated substrates. Biochemical Journal, 367 (3): 809-816.

Yokoyama: Department of Chemistry, University of Washington, Seattle, WA 98195, USA. []

12451 Camacho, M.D., Phillipson, J.D., Croft, S.L. and Rock, P., Marshall, S.J. & Schiff, P.L. Jr, 2002. In vitro activity of Triclisia patens and some bisbenzylisoquinoline alkaloids against Leishmania donovani and Trypanosoma brucei brucei. Phytotherapy Research, 16 (5): 432-436.

Camacho: Centre for Pharmacognosy and Phytotherapy, The School of Pharmacy, University of London, 29-39 Brunswick Square, London WC1N 1AX, UK.

12452 Chaudhuri, M., Sharan, R. & Hill, G.C., 2002. Trypanosome alternative oxidase is regulated post-transcriptionally at the level of RNA stability. [T. brucei] Journal of Eukaryotic Microbiology, 49 (4): 263-269.

Hill: Department of Microbiology, Meharry Medical College, Nashville, Tenessee 37208-3599, USA.

12453 Colman, P.M. & Smith, B.J., 2002. The trypanosomal trans-sialidase: Two catalytic functions associated with one catalytic site. Structure, 10 (11): 1466-1468.

Colman: Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville, Victoria 3050, Australia.

12454 Conway, C., Proudfoot, C., Burton, P., Barry, J.D. & McCulloch, R., 2002. Two pathways of homologous recombination in Trypanosoma brucei. Molecular Microbiology, 45 (6): 1687-1700.

McCulloch: The Wellcome Centre for Molecular Parasitology, The Anderson College, University of Glasgow, 56 Dumbarton Road, Glasgow G11 6NU, UK. []

12455 Cross, M., Kieft, R., Sabatini, R., Dirks-Mulder, A., Chaves, I. & Borst, P., 2002. J-binding protein increases the level and retention of the unusual base J in trypanosome DNA. [T. brucei] Molecular Microbiology, 46 (1): 37-47.

Borst: The Netherlands Cancer Institute, Division of Molecular Biology and Center for Biomedical Genetics, Plesmanlaan 121, 1066 CX Amsterdam, The Netherlands. []

12456 Crossman, A. Jr., Paterson, M.J., Ferguson, M.A.J., Smith, T.K. & Brimacombe, J.S., 2002. Further probing of the substrate specificities and inhibition of enzymes involved at an early stage of glycosyl-phosphatidylinositol (GPI) biosynthesis. [T. brucei] Carbohydrate Research, 337 (21-23): 2049-2059.

Brimacombe: School of Life Sciences (Chemistry), Carnelly Building, University of Dundee, Dundee, DD1 4HN, UK. []

12457 Denicola, A., Rubbo, H., Haden, L. & Turrens, J.F., 2002. Extramitochondrial localization of NADH-fumarate reductase in trypanosomatids. [T. brucei] Comparative Biochemistry and Physiology B - Biochemistry and Molecular Biology, 133 (1): 23-27.

Turrens: Department of Biomedical Sciences, University of South Alabama, Mobile, AL, USA. []

12458 Diehl, S., Diehl, F., El-Sayed, N.M., Clayton, C. & Hoheisel, J.D., 2002. Analysis of stage-specific gene expression in the bloodstream and the procyclic form of Trypanosoma brucei using a genomic DNA-microarray. Molecular and Biochemical Parasitology, 123 (2): 115-123.

Hoheisel: Division of Functional Genome Analysis, Deutsches Krebsforschungszentrum, Im Neuenheimer Feld 506, 69120 Heidelberg, Germany. []

12459 Fang, J. & Beattie, D.S., 2002. Rotenone-insensitive NADH dehydrogenase is a potential source of superoxide in procyclic Trypanosoma brucei mitochondria. Molecular and Biochemical Parasitology, 123 (2): 135-142.

Beattie: Department of Biochemistry and Molecular Pharmacology, PO Box 9142, West Virginia University School of Medicine, Morgantown, WV 26506-9142, USA. []

12460 Foster, J.A., Quan, N., Stern, E.L., Kristensson, K. & Herkenham, M., 2002. Induced neuronal expression of class I major histocompatibility complex mRNA in acute and chronic inflammation models. [rats, T. b. brucei] Journal of Neuroimmunology, 131 (1-2): 83-91.

Foster: Section on Functional Neuroanatomy, National Institute of Mental Health, 36 Convent Drive, Building 36, Room 2D15, Bethesda, MD 20892-4070, USA. []

12461 Fukai, Y., Nihei, C., Yabu, Y., Suzuki, T., Ohta, N., Minagawa, N., Nagai, K. & Kita, K., 2002. Strain-specific difference in amino acid sequences of trypanosome alternative oxidase. [T. brucei brucei] Parasitology International, 51 (2): 195-199.

Kita: Department of Biomedical Chemistry, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan. []

12462 Furuya, T., Kessler, P., Jardim, A., Schnaufer, A., Crudder, C. & Parsons, M., 2002. Glucose is toxic to glycosome-deficient trypanosomes. Proceedings of the National Academy of Sciences of the United States of America, 99 (22): 14177-14182.

Parsons: Seattle Biomedical Research Institute, Seattle, WA 98109, USA. []

12463 García-Salcedo, J.A., Nolan, D.P., Gijón, P., Gómez-Rodriguez, J. & Pays, E.A., 2002. A protein kinase specifically associated with proliferative forms of Trypanosoma brucei is functionally related to a yeast kinase involved in the co-ordination of cell shape and division. Molecular Microbiology, 45 (2): 307-319.

García-Salcedo: Laboratory of Molecular Parasitology, ULB - Institute of Molecular Biology and Medicine, 12 Rue des Professeurs Jeener et Brachet, B-6041 Gosselies, Belgium. []

12464 Igo, R.P. Jr, Weston, D.S., Ernst, N.L., Panigrahi, A.K., Salavati, R. & Stuart, K., 2002. Role of uridylate-specific exoribonuclease activity in Trypanosoma brucei RNA editing. Eukaryotic Cell, 1 (1): 112-118.

Stuart: Seattle Biomedical Research Institute, Seattle, Washington 98109, Department of Pathobiology, University of Washington, Seattle, Washington 98199, USA.

12465 Klingbeil, M.M., Motyka, S.A. & Englund, P.T., 2002. Multiple mitochondrial DNA polymerases in Trypanosoma brucei. Molecular Cell, 10 (1): 175-186.

Englund: Department of Biological Chemistry, John Hopkins Medical School, Baltimore, MD 21205, USA. []

12466 Li, Z.Y. & Wang, C.C., 2002. Functional characterization of the 11 non-ATPase subunit proteins in the trypanosome 19 S proteasomal regulatory complex. [T. brucei] Journal of Biological Chemistry, 277 (45): 42686-42693.

Wang: Department of Pharmaceutical Chemistry, UCSF, 513 Parnassus Avenue, San Francisco, CA 94143-0446, USA. []

12467 Liu, L., Liang, X.H., Uliel, S., Unger, R., Ullu, E. & Michaeli, S., 2002. RNA interference of signal peptide-binding protein SRP54 elicits deleterious effects and protein sorting defects in trypanosomes. Journal of Biological Chemistry, 277 (49): 47348-47357.

Michaeli: Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan 52900, Israel. []

12468 Magez, S., Stijlemans, B., Baral, T. & De Baetselier, P., 2002. VSG-GPI anchors of African trypanosomes: their role in macrophage activation and induction of infection-associated immunopathology. Microbes and Infection, 4 (9): 999-1006.

Magez: Laboratory of Cellular Immunology, Free University of Brussels/Flemish Interuniversity Institute for Biotechnology, Paardenstraat 65, 1640 Sint Genesius Rode, Belgium. []

12469 Maslov, D.A., Zíková, A., Kyselová, I. & Lukeš, J., 2002. A putative novel nuclear-encoded subunit of the cytochrome c oxidase complex in trypanosomatids. [T. brucei] Molecular and Biochemical Parasitology, 125 (1-2): 113-125.

Maslov: Department of Biology, University of California, Riverside, CA 92521, USA. []

12470 McConville, M.J., Ilgoutz, S.C., Teasdale, R.D., Foth, B.J., Matthews, A., Mullin, K.A. & Gleeson, P.A., 2002. Targeting of the GRIP domain to the trans-Golgi network is conserved from protists to animals. [T. brucei] European Journal of Cell Biology, 81 (9): 485-495.

Gleeson: Department of Biochemistry and Molecular Biology, University of Melbourne, Victoria 3010, Australia. []

12471 Müller, I.B., Domenicali-Pfister, D., Roditi, I. & Vassella, E., 2002. Stage-specific requirement of a mitogen-activated protein kinase by Trypanosoma brucei. Molecular Biology of the Cell, 13 (11): 3787-3799.

Vassella: Institut für Zellbiologie, Universität Bern, CH-3012 Bern, Switzerland. []

12472 Pal, A., Hall, B.S. & Field, M.C., 2002. Evidence for a non-LDL-mediated entry route for the trypanocidal drug suramin in Trypanosoma brucei. [Short communication] Molecular and Biochemical Parasitology, 122 (2): 217-221.

Field: Wellcome Trust Laboratories for Molecular Parasitology, Department of Biological Sciences and Centre for Molecular Microbiology and Infection, Imperial College of Science, Technology and Medicine, Exhibition Road, London SW7 2AY, UK.

12473 Pitula, J.S., Park, J., Parsons, M., Ruyechan, W.T. & Williams, N., 2002. Two families of RNA binding proteins from Trypanosoma brucei associate in a direct protein-protein interaction. Molecular and Biochemical Parasitology, 122 (1): 81-89.

Williams: Department of Microbiology, Witebsky Center for Microbial Pathogenesis and Immunology, State University of New York at Buffalo, Buffalo, NY 14214, USA. []

12474 Quijada, L., Guerra-Giraldez, C., Drozdz, M., Hartmann, C., Irmer, H., Ben-Dov, C., Cristodero, M., Ding, M. & Clayton, C., 2002. Expression of the human RNA-binding protein HuR in Trypanosoma brucei increases the abundance of mRNAs containing AU-rich regulatory elements. Nucleic Acids Research, 30 (20): 4414-4424.

Clayton: ZMBH, Im Neuenheimer Feld 282, D-69120 Heidelberg, Germany. []

12475 Schmidt, A., Clayton, C.E. & Krauth-Siegel, R.L., 2002. Silencing of the thioredoxin gene in Trypanosoma brucei brucei. [Short communication] Molecular and Biochemical Parasitology, 125 (1-2): 207-210.

Krauth-Siegel: University of Heidelberg, Neuenheimer Feld 506, 69120 Heidelberg, Germany. []

12476 Schmidt, T.J., Brun, R., Willuhn, G. & Khalid, S.A., 2002. Anti-trypano-somal activity of helenalin and some structurally related sesquiterpene lactones. Planta Medica, 68 (8): 750-751.

Schmidt: Institute für Pharmazeutische Biologie, Heinrich-Heine-Universtät Dusseldorf, Universitätsstrasse 1, Geb.26.23, 40225 Düsseldorf, Germany. []

12477 Steenkamp, D.J., 2002. Thiol metabolism of the trypanosomatids as potential drug targets. [T. brucei] IUBMB Life, 53 (4-5): 243-248.

Steenkamp: Division of Chemical Pathology, Faculty of Health Sciences, University of Cape Town, Observatory 7935, South Africa. []

12478 Tan, K.S.W., Leal, S.T.G. & Cross, G.A.M., 2002. Trypanosoma brucei MRE11 is non-essential but influences growth, homologous recombination and DNA double-strand break repair. Molecular and Biochemical Parasitology, 125 (1-2): 11-21.

Cross: Laboratory of Molecular Parasitology, The Rockefeller University, Box 185, 1230 York Avenue, New York, NY 10021-6399, USA. []

12479 Thomson, L.M., Lamont, D.J., Mehlert, A., Barry, J.D. & Ferguson, M.A.J., 2002. Partial structure of glutamic acid and alanine-rich protein, a major surface glycoprotein of the insect stages of Trypanosoma congolense. Journal of Biological Chemistry, 277 (50): 48899-48904.

Ferguson: Division of Biological Chemistry and Molecular Microbiology, The Wellcome Trust Biocentre, University of Dundee, Dundee DD1 6NR, UK. []

12480 Timms, M.W., van Deursen, F.J., Hendriks, E.F. & Matthews, K.R., 2002. Mitochondrial development during life cycle differentiation of African trypanosomes: Evidence for a kinetoplast-dependent differentiation control point. Molecular Biology of the Cell, 13 (10): 3747-3759.

Matthews: School of Biological Sciences, University of Manchester, Manchester M13 9PT, UK. []

12481 Ulbert, S., Cross, M., Boorstein, R.J., Teebor, G.W. and Borst, P., 2002. Expression of the human DNA glycosylase hSMUG1 in Trypanosoma brucei causes DNA damage and interferes with J biosynthesis. Nucleic Acids Research, 30 (18): 3919-3926.

Borst: Department of Molecular Biology and Centre of Biomedical Genetics, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, The Netherlands. []

12482 Wang, Z.F., Drew, M.E., Morris, J.C. & Englund, P.T., 2002. Asymmetrical division of the kinetoplast DNA network of the trypanosome. EMBO Journal, 21 (18): 4998-5005.

Englund: Department of Biological Chemistry, John Hopkins Medical School, Baltimore, MD 21205, USA. []

12483 Wickstead, B., Ersfeld, K. & Gull, K., 2002. Targeting of a tetracycline-inducible expression system to the transcriptionally silent minichromosomes of Trypanosoma brucei. [Short communication] Molecular and Biochemical Parasitology, 125 (1-2): 211-216.

Gull: Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK. []

12484 Zavala-Castro, J.E., Acosta-Viana, K., Baylon-Pacheco, L., González-Robles, A., Guzmán-Marín, E. & Rosales-Encina, J.L., 2002. Kinetoplast DNA-binding protein profile in the epimastigote form of Trypanosoma cruzi. Archives of Medical Research, 33 (3): 250-256.

Zavala-Castro: Laboratoire de Biología Celular, Centro de Investigaciones Regionales, Dr. Hydeyo Noguchi, UADY, Av. Itzaes 490 X 59, 97000 Mérida, Yucatán, México. []

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