Bovine Ephemeral Fever

[Kvet Forum]

A viral disease of cattle and buffalo, transmitted by mosquitoes and midges, and more commonly seen in young, immunologically naïve cattle. It is common in wet seasons, and is occasionally seen more when climatic conditions favour widespread distribution of the insect vectors. Typically, sickness is for three days, usually manifesting as fever, lameness and recumbency. Infection stimulates long lasting immunity.

Heavier, large framed animals are more affected. Infection of light cattle may be inapparent. Deaths may occur when recumbent animals cannot rise or when incapacitated animals incur further injury as a result of accidental slips or falls or are trampled by other cattle.


Clinical Signs and Diagnosis

Sudden onset of recumbency, stiffness and shifting lameness affecting multiple animals should raise strong suspicions. Early in an outbreak sporadic recumbent cases will be detected during pen inspection. Later, multiple animals become recumbent, have difficult rising, or may be affected by shifting lameness. Physical examination detects biphasic to polyphasic fever (40°–42°C) and muscle stiffness. Sometimes there is bilateral discharge from eyes and nose and drooling of saliva and drooped ears.

Specimens for laboratory confirmation of infection include serum collected from animals in the acute and convalescent stages of infection (2-3 weeks apart).


Treatment

• NSAIDs
• Supportive care for recumbent cows

Affected animals need rest – avoid mustering, transporting, loading or discharging sick animals. Recumbent animals are often hypocalcaemic and will benefit from administration of calcium borogluconate as well as non-steroidal anti-inflammatory drugs. Encourage heavy animals to stand to prevent compression damage to muscle and nerves. Mildly affected animals recover in several days without intervention.