Bovine ephemeral fever

Bovine ephemeral fever (BEF) also known as Three Day Sickness is an arthropod vector-borne disease of cattle and is caused by the Ephemerovirus virus of the Rhabdoviridae family of virus. The Rhabdoviridae are a class V virus according to the Baltimore classification of viruses. The BEF virus is a bullet or cone shaped virion which consists of a negative, single stranded RNA genome with a lipid envelope and 5 structural proteins. The envelope glycoprotein G contains type-specific and neutralizing antigenic sites. Theres has been recent evidence which demonstrated that the BEF virus induces apoptosis in several cell lines. It was however shown that apoptosis could be blocked by the caspase inhibitor (Z-VAD-fmk), indicating that bovine ephemeral fever virus induces caspase-dependent apoptosis in cultured cells.

Location

The virus has been found in tropical and subtropical regions of Asia, Africa and through eastern Australia.

Transmission

The virus is transmitted by an insect vector. The particular species linked to the virus are the biting midges Culicoides oxystoma and C. nipponensis.

Disease Characteristics

The characteristics of the disease are the sudden onset of fever, stiffness, lameness and nasal and ocular discharges. BEF often causes hypocalcaemia which in turn generates clinical signs such as depression, cessation of rumination, muscle tremors and constipation.

Although the pathogensis of the disease is complex it seems clear that the host inflammatory responses, mediated by the release of cytokines, are involved in the expression of the disease.

Diagnosis

The virus can be isolated from blood and can be identified by immunofluorescence and immunostaining. Rising antibodies in two samples taken 2-4 weeks apart also indicate infection.

Treatment

Calcium borogluconate and NSAIDs often help to alleviate clinical signs, but rest is absolutely imperative, for a mimimum of one week or death can still occur.

Control

A vaccine is available in Japan but is very expensive which limits its use. Movement regulations are in place in several countries.

References

• "Bovine Ephemeral Fever". wikivet.net. Retrieved 2012-02-23. 
• Hsieh, Y. C.; Chen, S. H.; Chou, C. C.; Ting, L. J.; Itakura, C.; Wang, F. I. (2005). "Bovine Ephemeral Fever in Taiwan (2001-2002)" (PDF). Journal of Veterinary Medical Science 67 (4): 411–416. doi:10.1292/jvms.67.411. PMID 15876792. 
• Chang, C. J.; Shih, W. L.; Yu, F. L.; Liao, M. H.; Liu, H. J. (2004). "Apoptosis Induced by Bovine Ephemeral Fever Virus". Journal of Virological Methods 122 (2): 165–170. doi:10.1016/j.jviromet.2004.08.016. PMID 15542140. 
• Hsieh, Y. C.; Wang, S. Y.; Lee, Y. F.; Chen, S. H.; Mak, P. O.; Chu, C. Y. (2006). "DNA Sequence Analysis of Glycoprotein G Gene of Bovine Ephemeral Fever Virus and Development of a Double Oil Emulsion Vaccine against Bovine Ephemeral Fever" (PDF). Journal of Veterinary Medical Science 68 (6): 543–548. doi:10.1292/jvms.68.543. PMID 16820709.