lungworm

The prevalence of endoparasites, their control and clinical relevance in donkeys can often cause confusion and concern to vets and owners alike. While donkeys can be affected by the same parasite species as horses, infection characteristics, presenting signs and symptoms of disease can differ. Donkeys do not always show obvious signs of disease until it is severe so it is important to know what to look out for when clinically assessing a donkey and how best to diagnose potential infection with parasites. There is a limited selection of anthelmintic products available for use in the donkey, so prescribing using the cascade is sometimes warranted. Careful consideration should be given to the choice and frequency of anthelmintic treatments in order to balance controlling disease with preserving anthelmintic efficacy.

Donkeys suffer from the same respiratory diseases as horses; however, owing to their nonathletic nature many conditions can present in a more advanced state before becoming clinically apparent. Anatomically, their respiratory tract is similar to the horse, with certain species-specific differences that are important to be aware of. Often donkeys do not receive the same level of routine care as horses, so many are not vaccinated against respiratory pathogens such as influenza or herpesviruses. Donkeys can act as a reservoir for certain infectious and parasitic respiratory diseases and the interpretation of diagnostic tests needs to be carried out with caution.

A field study was designed to investigate the re-establishment of patent lungworm infections in donkeys following an anthelmintic treatment regime which was effective against Dictyocaulus arnfieldi. In April 1979 faecal samples from 259 donkeys were examined and each animal classified as a negative, low positive or high positive excretor of lungworm larvae. During the summer the control group of 126 donkeys showed an increase in the number of excretors from 80 per cent in April to 91 per cent in October. At the same time there was a rise in the faecal larval output of individual animals so that by October 59 per cent were classified as high positive compared with only 20 per cent in April. The treated group of 133 donkeys received 3.5 g mebendazole daily for 5 days during April and as a result the number of excretors fell from 66 per cent pretreatment to 23 per cent one month after treatment. Despite exposure to infected pastures throughout the summer this figure was maintained at a comparatively low level and by October patent infections had been re-established in only 15 per cent of the donkeys that were negative after treatment.