• S.A. Ajayi, J.P. Fabiyi and I. Umo
Bovine anaplasmosis and babesiosis are enzootic in Nigerian indigenous cattle but outbreaks of clinical disease are relatively rare. The status of these diseases among exotic breeds in Nigeria is unknown.
This article reports severe losses among Friesian cattle at the National Veterinary Research Institute, Vom, Nigeria, apparently as a result of anaplasmosis and babesiosis occurring concurrently.
Eighty Friesians (78 heifers and 2 bulls) recently purchased from the United Kingdom by the National Veterinary Research Institute, Vom, arrived in the country by air in February 1980. All the heifers were in the latter half of pregnancy at the time they arrived at Vom. Within two weeks of their arrival in Nigeria, two had died of shipping fever and another of dystocia. Those remaining were immediately treated against shipping fever with chloramphenicol.
No further deaths were reported until approximately three weeks later, when animals started to die one after the other. Death and abortion were recorded almost daily for two weeks before anaplasmosis and babesiosis were diagnosed and the outbreak was brought under control with the use of imidocarb dipropionate (Imizol). At the end of the outbreak, 10 deaths and 13 abortions had been recorded.
Clinical manifestations observed during the outbreak included high fever (body temperature 40–42°C), anorexia, haemoglobinuria, low packed cell volume, anaemia and general weakness. Severely affected animals were found squatting and had difficulty in standing.
Parasitological findings from blood smears made from dead and aborted animals and stained with Giemsa, revealed high parasitaemia with Anaplasma marginale and Babesia bigemina. Theileria mutans parasites were also found in the blood of these animals, but they are known to be nonpathogenic in cattle. The degree of parasitaemia in the animals that survived and did not abort varied from low to very high. Smears from the liver, lung, kidney and spleen, stained in Giemsa, were found to contain Anaplasma- and Babesia-infected erythrocytes.
Necropsy findings were: marked jaundice, anaemic conditions of the mucous membranes and the skeletal muscles, blood-stained urine, watery blood and moderately enlarged livers.
Treatment of the remaining animals (some of them also showing moderately serious symptoms) with imidocarb dipropionate, using a single dose of 2.5 ml of a 12-percent solution per 100 kg of bodyweight administered intramuscularly, was followed by the rapid disappearance of the clinical symptoms and of Anaplasma and Babesia organisms in the blood smears.
Two main factors may have precipitated the present outbreak. The first, breed susceptibility to Anaplasma marginale and Babesia bigemina and the second, climatic and pregnancy stress.
Exotic breeds, especially those originating from temperate climates and, in particular, purebreds of high-performance milking cows, are known to be very susceptible to anaplasmosis and babesiosis (Riek, 1968; Ristic, 1968). Furthermore, it appears that the animals concerned were relatively old at the time of first exposure, which would have predisposed them to a more severe clinical infection.
The Friesian cattle were flown from the United Kingdom in February and came from a cold and wet winter to the hot and dry climate of the Jos Plateau. The sharp change in weather conditions may be expected to have had an adverse effect on the ability of the animals to resist massive infections.
In order to minimize losses in the future, these two factors - climate and susceptibility - should be borne in mind when exotic breeds are imported into Nigeria or other similar environments.
Before the recent introduction of imidocarb (Imizol) into the Nigerian market, tetracyclines and diminazene aceturate (Berenil) were the drugs of choice for the treatment of anaplasmosis and babesiosis respectively, in Nigeria. Apart from being highly effective against both anaplasmosis and babesiosis, as observed in the present instance, imidocarb is more convenient to use against mixed infections of this nature and also less expensive, since only a single dose treatment is necessary.
References
Riek, R.F. 1968. Babesiosis. In Infectious blood disease of man and animals. Vol. 2. Eds D. Weinman and M. Ristic. New York, Academic Press. p. 219–268.
Ristic, M. 1968. Anaplasmosis. In Infectious blood diseases of man and animals. Vol. 2. Eds D. Weinman and M. Ristic. New York, Academic Press. p. 474–536.
