DISEASE AND FERTILITY-CONTROL IN WILDLIFE AND FERAL ANIMAL POPULATIONS - OPTIONS FOR VACCINE DELIVERY USING VECTORS

A wide variety of vertebrates have been introduced into Australia during the 200 years of European settlement. Many have become pests causing significant environmental damage and having the potential to act as reservoirs of infectious diseases. Control of vertebrate pest species by fertility control is attractive on animal welfare grounds. Should exotic animal diseases become established in any of these feral animal populations vaccination would be an essential element in the control or eradication of disease. The only experience to date with vaccination of wildlife or feral animals has been the successful control of rabies in foxes in Europe by means of a live, attenuated rabies vaccine and a vaccinia-rabies recombinant vaccine. The feasibility of vaccination for disease control or fertility control in other vertebrate pests will depend on the development and evaluation of several vaccine vector strategies. The choice of vector, based on live viruses or bacteria, naked DNA coding for vaccine antigen or virus-like particles encapsidating genetic material coding for vaccine antigen, will depend on optimization of vector delivery strategies and immunogenicity of the vaccine antigen. Past experience from the vaccination of foxes against rabies suggests that rates of uptake of the vaccine-bait and immunogenicity of the vaccine will be crucial factors in determining the success of other vaccines controlling disease or fertility.