Diagnosis
The diagnosis of bovine ephemeral fever (BEF) or “three day sickness” during epidemics is made on the presence of lameness, muscular stiffness, pain, rapid spread of the disease through herds and short fever. The BEF virus can often be identified from a blood sample taken from animals in the fever stage of the disease. Alternatively, two blood samples, the first obtained during the fever stage and the second fourteen days later can be examined for development of antibodies to ephemeral fever virus.
Post-mortem examination of cattle that die is important to rule out other acute febrile diseases (rapid onset of fever) that often occur under the same conditions as ephemeral fever and present in a similar manner, such as tick fever or botulism.
Prevention
Control of insect vectors is not generally a practical means of controlling BEF.
A vaccine is registered for the prevention of BEF. It is only available through your veterinarian as it is a prescription only product. It is a two-part vaccine, with frozen and liquid components that must be mixed prior to administration.
Beginning in animals from 6 months, two injections of the vaccine 2 weeks to 6 months apart under the skin of the neck are necessary for long-lasting protection. Annual boosters are recommended prior to the BEF transmission season, after the initial course of injections have been given.
The 2-week interval between vaccinations is for use in outbreak situations. In all other cases, the initial two vaccinations should be at least 4 weeks apart. The flexible vaccination interval allows vaccination to commence in the winter months and allows vaccination to coincide with other management practices requiring yarding. However, the second vaccination needs to be timed prior to the known period of BEF transmission for that area. If this happens sooner than expected, and the cattle have had their initial dose of vaccine, administration of the second dose will lead to protection of all cattle within 7-10 days.
Care must be taken with this vaccine if the full benefit is to be obtained. It must be mixed and used on the same day.
The vaccine has provided good levels of protection against BEF and recent research has verified that the vaccine strain is still broadly cross protective against the strains of BEF virus circulating in Australia. In fact, the BEF virus has changed little in 40 years. Field trials have shown that some vaccinated cattle can develop mild disease, however the severity and duration of illness is very much less than in unvaccinated cattle.
Treatment
Always consult your veterinarian on the appropriate course of treatment for affected cattle.
Treatment with anti-inflammatory drugs has been shown to reduce the course of the disease when given in the first stage of illness and calcium injections may aid in the recovery of animals that are down. Most animals will recover if provided with water and shade, however, in extensive management situations this is often impossible to provide.
The BEF virus can paralyse the muscles of the throat and affect the ability to swallow. Do not force affected animals to drink. Inhalation pneumonia is a common complication of BEF infection and one of the causes of death in cattle affected by BEF.
See how to manage other arboviruses.
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