Bovine Ephemeral Fever (BEF), also known as “Three Day Sickness”, is a viral disease that primarily affects cattle and water buffalo. It is widely distributed in Africa, Asia (especially in China, Taiwan, the Korean Peninsula and Japan), the Middle East and Australia.  For the moment, BEF is not present in the Americas or Europe although its clinical course is usually brief and self-limiting, its economic impact on livestock farming can be significant due to the temporary loss of production/productivity and the costs associated with the management of affected animals.

Aetiology and transmission

BEF is caused by a virus of the genus Ephemerovirus, belonging to the family Rhabdoviridae. This virus is transmitted mainly by blood-sucking hematophagous insect vectors, such as mosquitoes (Culicoides spp. and Aedes spp.) and certain types of midges. Therefore, the incidence of the disease is closely related to climatic conditions and the presence of vectors, being more common in tropical and subtropical regions during periods of greatest vector activity, that is why most outbreaks occur from late spring to autumn

Clinical signs

Clinical signs of BEF tend to manifest suddenly and include:

• High fever (up to 41.5 ºC).
• Anorexia and decreased milk production.
• Muscle rigidity and difficulty moving, which may be confused with laminitis or joint lesions.
• Serous nasal and ocular discharge.
• Skin hypersensitivity and muscle tremors.
• In some cases, oedema in the limbs or joints.

The duration of these signs is usually three days, although in some animals the symptoms may persist for longer periods due to secondary complications.

Diagnosis

Diagnosis of BEF is based on observation of clinical signs, epidemiological history and exclusion of other diseases with similar presentations, such as Foot-and-Mouth disease or Infectious bovine rhinotracheitis. To confirm the diagnosis, laboratory tests can be performed as:

• Polymerase chain reaction (PCR) to detect viral RNA.
• Isolation of the virus in cell cultures.
• Serology to identify specific antibodies.

Treatment and control

Treatment for BEF is primarily symptomatic and supportive. It includes:

• Administration of nonsteroidal anti-inflammatory drugs (NSAIDs) to reduce fever and inflammation.
• Fluid therapy in dehydrated animals.
• Supplementation with vitamins and minerals to support recovery.

With regard to the/ Regarding prevention, it is recommended to:

• Reduce exposure to vectors by using repellents, nets, and environmental control.
• Vaccination in endemic regions, when available.
• Implement good management practices to minimize stress in cattle.

Economic impact and livestock management

Although mortality from BEF is low, economic losses can be significant due to temporary reduction in milk production, increase of veterinary costs and delay growth of affected animals. In addition, temporary immobility can hinder routine cattle handling and increase the risk of accidents.

For these reasons, the implementation of preventive measures and rapid diagnosis are essential to minimize the impact of this disease on bovine production systems.

Conclusions

BEF (bovine ephemeral fever) is a short-term viral disease with significant implications for livestock farming. Its control depends on a comprehensive approach that combines management strategies, vector control and, when possible, vaccination. Raising awareness among farmers and veterinarians about this disease is key to mitigating its effect and ensuring the health and productivity of the cattle herd.

References

• Walker, P. J., & Klement, E. (2015). “Epidemiology and control of bovine ephemeral fever.” Veterinary Research, 46(1), 124. https://veterinaryresearch.biomedcentral.com
• Murphy, F. A., Fauquet, C. M., Bishop, D. H., et al. (2012). “Virus taxonomy: Classification and nomenclature of viruses.” Elsevier Academic Press.
• Office International des Epizooties (OIE). (2021). “Manual of Diagnostic Tests and Vaccines for Terrestrial Animals.” https://www.oie.int