Observations on the recent epizootic of bovine ephemeral fever in Saudi Arabia

Observations of the epizootic of bovine ephemeral fever which occurred in S audi Arabia during 1996 are presented. The investigations included the coll ection of epidemiological data from affected farms and the testing of sera for antibodies to the virus. The authors report a mean morbidity rate of 50 % and a mean case fatality rate of 0.3%. Of the infected cattle, 4% were af fected by recumbency, the majority of these recovered (89%). The clinical s igns observed in affected cattle were uniform throughout the region concern ed. The features of the outbreak, obtained through field investigations, we re considered in relation to the ecological and meteorological conditions w hich were prevalent at the time. The outbreak occurred during the summer mo nths (May to October) in the central and eastern regions of Saudi Arabia, w ith the initial infection reported at the Al-Ahsa oasis. Farms which were s ubsequently affected were all reported to possess areas of stagnant water s uitable for the reproduction of the vectors of the disease (Culicoides spp. and mosquitoes). To conclude, the authors discuss precautions to prevent f uture outbreaks of bovine ephemeral fever in Saudi Arabia.