There are two forms of Malignant Catarrhal Fever:
- Wildebeest Associated
- Sheep Associated
The Wildebeest Associated Malignant Catarrhal Fever affects cattle grazing with calving Wildebeest in Africa.
The cause of the disease has been identified as a herpes virus.
In Australia Malignant Catarrhal Fever is associated (usually) with lambing ewes. There have been reports of it being associated with weaner sheep and goats. It is suspected that sheep-associated Malignant Catarrhal Fever is also caused by a herpes virus.
Cattle (and other bovids) and deer are affected. Rabbits and Guinea Pigs can be infected experimentally.
Malignant Catarrhal Fever - The Disease in Deer
The disease occurs in 13 species of deer and almost NEVER in Fallow Deer.
Père David’s Deer is the most susceptible followed by Red Deer and Elk.
Deer do not need to be closely associated with sheep. It is thought that the infection can be windborne for up to 1 kilometre. Transmission is also possible from trucks used to carry sheep and then deer.
Stress is probably the major cause of initiating the disease. The incidence of the disease rises during winter in herds that have no protection from the cold.
The most common manifestation of Malignant Catarrhal Fever in deer is a rapid onset of bloody diarrhoea, dark stained urine, depression and death within 48hrs.
Animals that live longer than that develop the chronic head-and-eye form that is typical of cattle. There is conjunctivitis, excessive salivation and eventually both eyes become cloudy. These animals live for a few days to a few weeks.