S. Grimes

The introductory paper of this conference confirms the importance of Newcastle disease (ND) as a major constraint to improving the productivity of family poultry in many countries. The author recognizes the problem of imported ND vaccines being expensive and that many of these vaccines are heat labile. This renders the vaccines ineffective for use in family poultry if a cold chain is not available, as is often the case in developing countries. Thermostable vaccines are therefore appropriate in these situations.

The Australian Centre for International Agricultural Research (ACIAR) has funded the research and development of thermostable ND vaccines. This work has been conducted over the last fifteen years and supervised by Professor Peter Spradbrow of the School of Veterinary Science and Animal Production at the University of Queensland. Two thermostable vaccine strains were developed, V4 and I2. Thermostable V4 vaccine is now made commercially by Fort Dodge (previously Websters) and the Malaysian Technology Development Corporation.

The University of Queensland stores the freeze dried I2 master seed which is supplied at no cost for use in developing countries for local production of thermostable ND vaccine. To date the I2 master seed has been distributed to nine countries. The recipients of the master seed then face the challenge of producing and distributing ND vaccine on a sustainable basis. In order to transfer the skills required to make and test the vaccine and ensure its distribution to village chickens, a series of practical workshops have been convened. These workshops have been held in association with extension workshops attended by administrators and extension workers who are a vital link between the laboratory and the field. These are the people who are ultimately responsible for distributing the vaccine and organizing vaccination programs in rural villages.

Following is a brief summary of the role and outcomes of these practical laboratory workshops including details of where, when, who participated and funding source.

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The strategy of holding practical laboratory workshops in developing countries was devised primarily to transfer the technical skills required to produce and test ND vaccine. The organizing and convening of the workshops require considerable collaboration between the Australian veterinary research team headed by Professor Peter Spradbrow and counterparts within the host country. Communications have been greatly facilitated by the use of e-mail where possible.

This collaborative spirit is maintained throughout the workshop and fosters mutual understanding of existing technologies between the partners. Constraints to ND vaccine production and distribution are discussed and planning for overcoming these constraints initiated. The workshops are conducted in a central veterinary laboratory in the working environment of the participants. Simple low cost materials are used. Each participant receives a laboratory manual (Spradbrow et al., 1998) and additional laboratory materials are supplied according to the requirements of the participating laboratory and the budget allocation. The workshops are planned to enable one Australian technician to effectively transfer skills to sixteen participants who each have the opportunity to practice the practical skills required to produce and test ND vaccine.

On completion of the workshop, participants are encouraged to maintain a working network with each other and with the Australian research team. A newsletter based on ND vaccine production in the host country has been suggested as a means of developing a team spirit and sharing information, results and problems.

The Australian team offers on-going technical assistance and advice via e-mail, fax and regular correspondence as required. A portfolio of copies of relevant research papers is prepared and supplied for perusal by the participants. Often they do not have access to a library with a collection of journals. Participants are encouraged to plan and implement efficacy trials of locally produced thermostable ND vaccine and to consider submitting the results of such trials for publication in international journals. Professor Spradbrow has offered to help with advice regarding the methodology of vaccine trials and with editorial advice for the analyse of results of the trials for publication.

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The training objectives of these workshops are as follows:

1. To prepare ND vaccine by a seed lot system. For those laboratories that have imported the I2 master seed virus, this includes propagation of the virus in embryonated eggs and preparation of aliquots of an I2 working seed;

2. Quantal infectivity assays of ND virus, calculations of infectivity titre using Reed Muench formula;

3. Detection and titration of ND virus haemagglutinin;

4. Detection and titration of ND haemagglutination inhibition antibodies in serum using standardized positive and negative serum;

5. Collection and processing of blood samples from chickens;

6. Application of ND vaccine to, and recovery of virus from feed;

7. Discussion of experimental methodology, recording results in laboratory day books, calculations of mean antibody titres and analysis of data collected from vaccination trials

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Practical vaccine production workshops have been held in four countries, South Africa, Tanzania, Ghana and Myanmar. Below are details of these workshops and future workshops currently being planned for Bhutan and Cambodia

1. South Africa, December 1995. Funded by ACIAR, held at the Poultry Reference Laboratory, University of Pretoria, Onderstepoort. Attended by veterinarians and technicians from fourteen African countries

2. Tanzania, December 1996. Funded by ACIAR, held at Animal Disease Research Institute, Department of Research Development, Ministry of Agriculture and Cooperatives, Dar es Salaam. Attended by veterinarians and technicians from six Regional Veterinary Centres, and one technician from Mozambique

3. Ghana, January 1997. Funded by World Bank and GRM International Pty Ltd. Attended by one veterinarian and two technicians from each of four veterinary laboratories

4. Myanmar, October 1998. Funded by FAO Food Security Project, held at Central Vaccine Laboratory, Livestock Breeding and Veterinary Department, Ministry of Livestock and Fisheries. Attended by fourteen departmental veterinarians and one academic from the Institute of Animal Husbandry and Veterinary Sciences

5. Bhutan, March 1999. A workshop funded by AusAid is currently being planned, to be held at the Vaccine Production Centre, Crop and Livestock Division, Ministry of Agriculture

6. Cambodia, mid 1999. A workshop funded by FAO is currently being planned.

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Vietnam: The National Veterinary Company (NAVETCO) in Ho Chi Minh City, has used the I2 master seed for production of thermostable vaccine. This vaccine is designated AVF/NDV-HR, AVF standing for Australian Vietnam Friendship. Prior to producing the vaccine on a larger scale for distribution to regional areas, scientists at NAVETCO carried out laboratory and village trials of I2 vaccine for use under Vietnamese conditions (Tu et al., 1998). The vaccine is now widely available in Vietnam for use in village chickens and is exported to Laos and Cambodia. This successful use of the I2 master seed is described as a model for local and sustainable production of thermostable ND vaccine in a developing country.

Tanzania: Dr Ann Foster and colleagues conducted field trials in villages near Dodoma. They tested the efficacy of Websters V4 for use by rural farmers to improve the productivity of their chickens (Foster et al., 1998). Field trials using Websters V4 vaccine were also carried out in the Mtwara and Lindi regions of the Southern zone of Tanzania (Salum et al., 1997). The thermostable I2 vaccine has been produced in Tanzania and successfully tested in village chickens kept under laboratory conditions (Wambura et al., submitted for publication).

Ghana: The workshop held in Ghana was part of the Newcastle disease vaccine component of the National Livestock Services Project. During the workshop, participants monitored the serological response of chickens in a laboratory trial using Websters V4 vaccine. Dr Jonathan Amakye-Anim conducted this trial in collaboration with Dr Alders and Professor Spradbrow (Amakye-Anim et al., 1998). Village trials in Ghana have been initiated and the I2 master seed has been imported.

Myanmar: Dr Hla Myint, Advisor to the Livestock Breeding and Veterinary Department, Insein, Yangon, has indicated in a personal communication to Professor Spradbrow, that 300 000 doses of I2 ND vaccine have been produced in the Central Vaccine Laboratory since the workshop was held. This vaccine is currently being tested at the Central Diagnostic Laboratory and the Assay Laboratory. Arrangements are being made for field trials in seven States and Divisions.

Mozambique: Mrs Amalia Mangonhela from INIVE (Central Veterinary Laboratory), Maputo participated in the Tanzanian workshop. She is involved in the production and testing of the I2 vaccine in Mozambique in collaboration with Dr Robyn Alders who co-ordinates the ACIAR funded project "Investigations into the control of Newcastle disease in village chickens in Mozambique".

South Africa: Dr Dirk Verwoerd of the Onderstepoort Veterinary Institute co-ordinates a Newcastle disease virus programme. The I2 master seed has been imported and wet I2 vaccine prepared for use in field trials (Personal communication).

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It is hoped that the workshops will play a key role in achieving local production and quality assurance of cheap thermostable ND vaccine. The importation of the I2 master seed is promoted for use in central and regional laboratories to produce the thermostable vaccine. The vaccine can then be distributed as a wet or freeze dried vaccine. Sustainable production of vaccine is the goal. This can be achieved by the implementation of a cost recovery programme using affordable locally produced vaccine.

It is also hoped that having practised the technical skills, some of the participants will implement the small-scale production and testing of thermostable vaccine in their own laboratories. They are encouraged to describe their progress in publications devoted to family poultry such as the International Network for Family Poultry Development Newsletter. ACIAR and the University of Queensland recently launched a website titled "Improvements in rural poultry in developing countries" at the address http://www.vsap.uq.edu.au/RuralPoultry. It is hoped that those participants who have access to Internet will look at it, leave their names in the guest book and participate in the discussion forum. The Laboratory Manual used by participants of these workshops and sections of the Field Manual (Alders and Spradbrow, 1999) supplied to participants of the extension workshops can be viewed and downloaded from this website

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Alders, R.G. and Spradbrow, P.B. (1999): Newcastle disease in village chickens, A Field Manual.

Amakye-Anim, J., Alders, R.G. and Spradbrow, P.B. (1998): Trials with V4 Newcastle disease vaccine in Ghana. Scientific Proceedings of the Fourth Asia Pacific Poultry Conference, Melbourne, Australia, p. 124

Foster, A., Chitukuro, H.R., Tuppa, E., Mwanjala, T. and Kusila, C. (1998): Thermostable Newcastle disease vaccines in Tanzania. Scientific Proceedings of the Fourth Asia Pacific Poultry Health Conference, Melbourne, Australia, p. 124

Salum, M.R., Hyera, J.M.K. and Kapaga, A.M. (1997): Immunization of village chickens using thermostable Newcastle disease (ND) vaccines: Observations on field vaccination trials using ND V4 vaccine in Southern zone of Tanzania. Report submitted to the Department of Research and Training, Ministry of Agriculture and Co-operatives, Dar es Salaam, Tanzania, pp. 24

Spradbrow, P., Bensink, Z. and Grimes, S. (1998): Small-scale production and testing of Newcastle disease vaccine. Laboratory Manual, pp. 31.

Tu, T.D., Phuc, K.V., Dinh, N.T.K., Quoc, D.N. and Spradbrow, P.B. (1998): Vietnamese trials with a thermostable Newcastle disease vaccine (Strain 12) in experimental and village chickens. Preventive Veterinary Medicine 34: 205-214.

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