Bovine ephemeral fever virus

Test code: S0204 - Ultrasensitive detection of bovine ephemeral fever virus by reverse transcription coupled real time PCR

Bovine ephemeral fever virus (BEFV) is a member of the genus Ephemerovirus in the family Rhabdoviridae. The virus is a bullet or cone shaped virion, consisting of a negative, single stranded RNA genome with a lipid envelope and 5 structural proteins. There is only one serotype. Other members of this genus include Adelaide River virus, Kimberley virus, Berrimah virus, Puchong virus and Malakal virus, and these members can cross-react in some serological tests with BEFV.

This virus infects cattle and water buffalo, and can result in significant economic loss due to reduction in milk production, poor condition, abortion, temporary infertility in bulls, and prolonged recovery in some animals. Bovine ephemeral fever occurs in Africa, Australia, Asia and the Middle East among Bos species cattle breeds and water buffalo (Bubalus bubalis).

Antibodies to BEFV have been reported in domesticated deer and goats, as well as many wild ruminants including Cape buffalo, hartebeest, waterbuck, wildebeest, kudu, deer, antelope and giraffes. Most of these seropositive animals are found in Africa. These seropositive animals may have contacted the virus but have not developed any disease symptoms.

Mosquitoes are suspected to be the most important biological vectors for the transmission of this virus. The virus has been isolated from a mixed pool of Culicine and Anopheline mosquitoes, as well as Anopheles bancroftii, in Australia, and from Culicoides (biting midges) in both Africa and Australia.

Infected animals may develop mild to severe symptoms within 1-10 days after contacting the virus. Asymptomatic infections are also seen. The classic clinical course of the disease begins with a fever, which is often biphasic, triphasic or polyphasic. The temperature peaks typically occur 12 to 18 hours apart. Symptoms tend to get worse after each phase of fever. However, most animals recover after 2-3 days of infection – this is why the disease is sometimes called "Three Day Sickness."

Bovine ephemeral fever can be confused with other diseases, such as early Rift Valley fever, heartwater, bluetongue, botulism, babesiosis or blackleg. The salivation symptom may also resemble foot-and-mouth disease, but no vesicles are found. Differential diagnosis often requires laboratory testing. Serology may be used to detect the rising antibody titer, but some time is required for the antibody titer to rise to a detectable level. Molecular detection by PCR is rapid, sensitive and specific, and is often used to detect the virus (Finlaison et al., 2014).

Utilities:

• Help confirm the disease causing agent
• Shorten the time required to confirm a clinical diagnosis of BEFV infection
• Help ensure that animal herds and populations are free of bovine ephemeral fever virus
• Early prevention of spread of the virus among animals
• Minimize human exposure to the virus
• Safety monitoring of biological products that derive from animals

References:
Finlaison, D.S., Read, A.J., Zhang, J., Paskinb, R., and Kirklanda, P.D. (2014) Objective Application of a real-time polymerase chain reaction assay to the diagnosis of bovine ephemeral fever during an outbreak in New South Wales and northern Victoria in 2009–10. Aust. Vet. J. 92: 24-27.

Specimen requirements: 0.2 ml whole blood in EDTA (purple top) tube, or 0.2 ml fresh or frozen tissue.

Contact Zoologix if advice is needed to determine an appropriate specimen type for a specific diagnostic application. For specimen types not listed here, please contact Zoologix to confirm specimen acceptability and shipping instructions.

For all specimen types, if there will be a delay in shipping, or during very warm weather, refrigerate specimens until shipped and ship with a cold pack unless more stringent shipping requirements are specified. Frozen specimens should be shipped so as to remain frozen in transit. See shipping instructions for more information.

Turnaround time: 2 business days

Methodology: Qualitative reverse transcription coupled real time PCR

Normal range: Nondetected