Disease management strategies for wildlife.

Three basic forms of management strategies exist for wildlife disease, as follows: prevention of introduction of disease, control of existing disease or eradication. Management may be directed at the disease agent, host population, habitat or be focused on human activities. Disease agents may be dealt with in the environment through disinfection or in the host through treatment. Disinfection and pesticides used to destroy agents or vectors are limited to local situations, may have serious environmental effects and may result in acquired resistance. Difficulty in delivering treatment limits chemotherapy to local situations. Host populations may be managed by immunisation, by altering their distribution or density, or by extirpation. Immunisation is best suited for microparasitic exogenous infections with a low reproductive rate and in populations which have a low turnover. Mass immunisation with oral baits has been effective, but this strategy is limited to a few serious diseases. It is difficult to move wild animals and techniques to discourage animals from entering an area become ineffective rapidly. The setting up of fences is feasible only in local situations. Selective culling is limited to situations in which affected individuals are readily identifiable. General population reduction has had little success in disease control but reducing populations surrounding a focus or creating a barrier to disease movement have been successful. Population reduction is a temporary measure. Eradication of a wildlife population has not been attempted for disease management. Habitat modification may be used to reduce exposure to disease agents, or to alter host distribution or density. Management of diseases of wild animals usually requires a change in human activities. The most important method is by restricting translocation of wild animals to prevent movement of disease.