This is an almost invariably fatal disease of cattle of worldwide distribution.

INCIDENCE

The disease is not that common and usually arises as a single-animal incident.

AETIOLOGY

MCF is caused by a herpesvirus, which is excreted by healthy sheep. The viruses are not transmitted naturally between cattle hence cattle are dead-end hosts. 

Affected cattle show the following signs:- inappetance, marked loss of condition, extreme depression and high fever, occasionally with nervous signs such as excitement and muscle tremors. There is marked enlargement of superficial glands and sooner or later, a copious discharge appears which accumulates around the eyes and nose. Excessive salivation occurs and breathing difficulties and snoring due to the accumulation of the discharge. Inflammation and congestion around the eyes can result in blindness.

Usually mouth lesions are present when the temperature first rises. In addition to congestion, distinct ulcers develop inside the cheeks. Erosions also occur on the palate. Halitosis becomes very marked as the disease progresses.

The character of the faeces varies considerably from case to case. Constipation may be present but usually at least during some part of the course of the condition, diarrhoea occurs, varying in quality from scanty soft faeces to profuse diarrhoea.

Further prominent signs include widespread, moist skin lesions and urine infections.

Cattle which develop malignant catarrh usually die within 5-10 days and the fever usually persists almost until death.

EPIDEMIOLOGY

In most countries in the world, sheep are believed to be the reservoir for infection of cattle and to harbour the virus without developing clinical signs. In Britain, confirmed cases are usually known to have had contact with lambing ewes and most cases are seen during the period between February and June.

The disease in cattle seems to be non-contagious to other cattle.

DIAGNOSIS

A confident diagnosis can almost always be made on consideration of the wide spectrum of clinical signs. In addition, the histopathological lesions (and their wide distribution) are sufficiently characteristic to be looked upon as confirmatory.

TREATMENT

None. (MCF should be looked upon as an invariably fatal disease; if claims are made regarding successful treatment, then there should be doubts about the original diagnosis).

CONTROL

No vaccine exists.