Disease control measures for rabbit

When a high standard of hygiene and careful management are practised (IFS, 1978), one distinct attribute of rabbit farming is the relatively low incidence of epidemic diseases. Rabbits do not require routine vaccination or medication for the prevention or treatment of specific diseases. This is an important factor since, in other livestock species, a lack of appropriate drugs is sometimes a major constraint to successful production. When a disease does occur in rabbit farming, local remedies can often be effectively used in treatment. One common disease condition, referred to as ear mites and caused by an external parasite, Psoroptes cuniculi, can be both prevented and treated by applying drops of an oil-kerosene solution directly inside the ear canal. Vegetable oil, red palm oil and even clean engine oil may be used. For the control of digestive disorders, diarrhoea and constipation for example, various medicinal herbs and green vegetables used in Cameroonian tribal cultures have been observed to provide similar therapeutic results in rabbits (Lukefahr and Goldman, 1985). Other conditions, such as abscesses, cannibalism, skin mange and warbles, have likewise been inexpensively controlled with proven local measures.

In tropical countries, Owen (1976) observed a trend of lower disease incidence and/or higher productivity levels in rabbit operations managed as small-scale family units as opposed to intensive, commercial units. In large operations, on the other hand, management quality per animal may be inferior and close confinement may mean greater likelihood of rapid disease outbreaks, particularly of myxomatosis and pasteurellosis. Where large central rabbit operations exist, therefore, it is imperative that stringent levels of hygiene, the culling of diseased animals and proper quarantine measures be maintained.

Two diseases of major global concern to rabbit producers are coccidiosis and pasteurellosis. While coccidiosis can largely be prevented and treated, the disease often goes undiagnosed and serious physical damage occurs; for example, liver damage and severe weight loss. Raising rabbits on the ground aggravates the problem because of the more direct exposure to the infectious agent. Various sulpha-based drugs have shown good results in controlling rabbit coccidiosis (Aduma, 1978). Sanitation is a critical determinant in the control of episodic frequency and morbidity levels due to coccidiosis outbreaks.

Pasteurellosis is a disease caused by a bacterium (Pasteurella multocida) which affects nearly all body tissues. Symptoms of the disease include muco-purulent nasal discharge, pneumonia, dermal abscesses, conjunctivitis, infertility and death. Only limited success is noted with treatment using broad-spectrum and sulphabased drugs. Moreover, only a culture test can confirm definitive exposure to P. multocida. In well-managed rabbit herds, however, the disease is rarely a problem. At present, the best means of controlling pasteurellosis is through correct housing design, strict culling of infected animals and/or selection of healthy stock and quarantine. Some laboratories and universities have developed specific pathogen-free (SPF) stock that are pasteurella-free. Projects have in some cases established rabbit populations through SPF stock importations. General guidelines for rabbit stock importation, with regard to disease control and sound genetic resource utilization, are given in the Box.

Pasteurellosis has been detected in certain rabbit projects in developing countries and it has been the opinion of project managers that the disease was introduced by the original imported stock. In one major rabbit project in China, some rabbits suffered sneezing, nasal discharge and matted inner forepaws, symptoms of a seemingly rare respiratory disease. A team of veterinarians was perplexed as to the cause of the disease, but a rabbit specialist later recognized the disease as a classic case of pasteurellosis (Milne, 1982). Unfortunately, this scenario has occurred repeatedly in several other countries.

A paper from China by Xu, Du and Liu (1988) reported the serious outbreak of a new viral disease (rabbit haemorrhagic disease virus -RHDV) which has manifested itself in parts of Asia and Europe, and more recently in North America. Body organs such as the lungs, liver and spleen are severely affected. To date, no effective treatment is available since the immunological mechanism is not understood. Strict quarantine measures to control further spread of this disease are now being implemented (Patton, 1989).