Development of a vaccine for the control of Gumboro in village and small poultry holdings in Indonesia

AH/2000/083: Development of a vaccine for the control of Gumboro in village and small poultry holdings in Indonesia

Indonesia

University of Melbourne, Australia

Dr Jagodina Ignjatovic
Phone: (03) 9731 2036
Fax: (03) 9731 2366
Email: jagodai@unimelb.edu.au

• Research Institute for Veterinary Science, Indonesia

$575,704

01/01/2001 - 31/12/2003

01/01/2004 - 31/12/2007

Dr Peter Rolfe

Infectious bursal disease, or Gumboro, is the second most serious viral disease of poultry (after Newcastle disease) in Indonesia. Infection with the virus suppresses the animal's normal immune response, with the result that other infections can readily take hold. The economic impact of IBD in Indonesia has been worsened by the appearance in 1991 of very virulent strains of the virus (referred to as vvIBDV). These variants caused up to 30% mortality in broilers and 60% in layers. Surviving birds perform poorly because of severe immunosuppression by the virus.

Chicken meat is the main source of dietary protein in Indonesia. But since the economic crisis of 1997, there has been a decline in availability of poultry meat and eggs. The traditional backyard farming of kampung (native) chickens continues, with more households adopting ways of intensive growing in response to the high demand for kampung chicken meat.

Unfortunately, most smallholders and backyard chicken farmers do not vaccinate against vvIBDV in spite of frequent heavy losses, because of the vaccine price and the packaging sizes available. As well, many kampung chicken owners are not aware of the importance of the disease. Consequently, sub-clinical disease, causing poor growth and non-specific deaths, is often not recognised.

Australia is one of the few countries free of vvIBDV, but Indonesia is a potential source for its introduction. Earlier collaboration between Australian and Indonesian researchers studying the virus led to the approach by Indonesia's BALITVET to ACIAR for help in developing a local vaccine. Locally produced vaccines would be cheaper, and packaging could be tailored for use by smallholders.

This project builds on earlier work funded by AusAID, and will carry out the research to develop and produce a local vaccine in Indonesia for the newly emerged virulent infectious bursal disease (vvIBD).

The first step will be to select clones from vvIBDV strains that have been grown in tissue culture and characterise these clones at a molecular level. In the second stage scientists will select clones that show reduced virulence. These will then be used to choose a variant that is safe for the development of a vaccine based on attenuation (weakening) of the virus's virulence. Such a clone must still be immunogenic in order to be effective. Once found, this will be developed into a vaccine that will be tested on kampung chickens. The team will evaluate the effectiveness of various routes of vaccination.

The scientists will also test the ability of the standard ELISA assay to differentiate between strains of vvIBDV on farms with outbreaks of Gumboro. An ELISA kit based on locally occurring antibodies will be developed for regional veterinary services to use in identifying IBDV strains. Smallholder and kampung chicken growers with a previous history of vvIBDV outbreaks will be used as sources of antibody-positive chickens for vaccine evaluation.

The work will also involve the creation of an IBDV network, linking different institutions across Indonesia.

Outcomes for this project are currently being prepared