Abstract :
This paper provides a brief review of the widespread and economically important disease
of coccidiosis. At one time, coccidia were considered to be virtually non pathogenic, but
by the 1960s they were recognised to cause disease. Almost all young lambs and kids will
be exposed and become infested during their early life and there are similarities and differences
between the two host species. Coccidian species are mainly identified by their
morphology and the predilection site within the host’s alimentary tract. At one time, it
was thought the species in goats and sheep were the same, but cross transmission studies
have shown that the coccidia are host-specific. Currently, 11 coccidian species are recognised
in sheep and nine in goats. Two sheep species are known to be highly pathogenic
and these two parasites inhabit both the small and large intestine. Much less work has
been undertaken on goat coccidia, although it is considered that several Eimeria species
might be pathogenic. Often, clinical signs in sheep and goats are limited and mild, but it
is common for animals to decrease their weight gain or even lose weight. The faeces may
alter and there may be diarrhoea. Whilst there are production losses, there has been little
quantification in sheep or goats. Moreover, infested animals appear more susceptible to
other infections. Diagnosis is often more difficult than it seems. Because of problems, this
has resulted in suggestions that the diagnosis of coccidiosis should be based on a number
of parameters: epidemiology, clinical signs, oocyst counts in faecal samples, pathological
findings and, finally, clinical response to treatment. There are several preparations licensed
in the United Kingdom for sheep, but none for goats. There are also several management
factors which can assist in control of the disease, but often medication has to be used to
prevent the disease.
