If animals recover, they are solidly immune. Morbidity is usually low, however, mortality is high. Sheep associated MCF occurs sporadically on a worldwide basis. In Africa, the wildebeest is the reservoir. Elsewhere, sheep are thought to be the reservoir.
Close contact is regarded as essential for transmission via nasal discharge.
Wildebeest and sheep have naturally occurring, inapparent infections. Cattle are secondary hosts. Erosions and hyperemia in the GI tract. Perhaps, whitish focal areas in kidneys. It is highly infectious and occurs in acute, subacute and chronic septicemic forms.