Abstract
Parasitic bronchitis, caused by the nematode Dictyocaulus viviparus. is a serious disease of cattle. For over 40 years, a radiation-attenuated larval vaccine (Bovilis® Huskvac, Intervet UK Ltd) has been used successfully to contol this parasite in the UK. Once vaccinated, animals require further boosting via field challenge to remain immune however there have been virtually no reports of vaccine breakdown. Despite this, sales of the vaccine decreased steadily in the 1980s and 90s; this was probably due to farmers' increased reliance on long-acting anthelmintics to control nematode infection in cattle. This method of lungworm control can be unreliable in stimulating protective immunity, as it may not allow sufficient exposure to the nematode. Such animals remain susceptible to disease when subsequently exposed to D. viviparus larval challenge. Evidence of this phenomenon has been provided by the documented increase in the numbers of parastitc bronchitis outbreaks in the UK in the last 20 years, especially ...
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have