Observations on rift valley fever virus and vaccines in Egypt

Rift Valley Fever virus (RVFV, genus: Phlebovirus, family: Bunyaviridae), is an arbovirus which causes significant morbidity and mortality in animals and humans. RVFV was introduced for the first time in Egypt in 1977. In endemic areas, the insect vector control and vaccination is considering appropriate measures if applied properly and the used vaccine is completely safe and the vaccination programs cover all the susceptible animals. Egypt is importing livestock and camels from the African Horn & the Sudan for human consumption. The imported livestock and camels were usually not vaccinated against RVFV. But in rare occasions, the imported livestock were vaccinated but with unknown date of vaccination and the unvaccinated control contacts were unavailable for laboratory investigations. Also, large number of the imported livestock and camels are often escaped slaughtering for breeding which led to the spread of new strains of FMD and the introduction of RVFV from the enzootic African countries. This article provide general picture about the present situation of RVFV in Egypt to help in controlling this important disease.

Pathological studies on postvaccinal reactions of Rift Valley fever in goats

RVF live attenuated vaccine (Smithburn strain) was evaluated by using goats as experimental animal. The results indicate that this vaccine cause severe deleterious pathological changes in liver especially in kids and causing abortion in pregnant does. The virus was seen to be propagated inside hepatic cells forming intranuclear inclusions which was also seen by E.M. Viral antigens were detected in hepatic cells, gall bladder, endothelial lining of blood vessels, leukocytes, kidneys and heart by using immunoflourescent technique. It could be concluded that the use of live attenuated vaccine of RVF (Smithburn strain) for immunization of live stock is not safe in Egypt as it considered an endemic area.