Rift Valley Fever (RVF), caused by RVF virus (RVFV), is an acute, mosquito-borne viral disease that has a significant global threat to humans and livestock.  The causative agent belongs to the genus Phlebovirus of family Bunyaviridae. It is an emerging pathogen, whose range has recently expanded from East Africa, across sub-Saharan Africa to North Africa, and to the Arabian Peninsula. Tanzania is amongst the countries of the sub-Saharan Africa that have encoutered a number of disease epidemics. Relatively little is known about the trend of occurrence, epidemiological factors and socio-economic impact related to previous epidemics in the country.This review was conducted to provide comprehensive update on Rift Valley Fever (RVF) in Tanzania, with particular attention devoted to trend of occurrence, epidemiological factors, socio-economic impact and measures which were applied to its control. Ultimately, the information gathered in this study will help to improve better understanding of epidemiology of disease and areas at higher risk important for contingency plans for outbreak management, proper allocation of resources to prevent further occurrence and spread of this disease. Information presented in this paper was obtained through extensive literature review. RVF was documented for the first time in Tanzania in 1977. This was followed by epidemics in 1997 and 2007. Contrary to the latest epidemic in 2007 sporadic cases of RVF during the previous epidemics were confined to mainly livestock and mostly affecting northern parts of Tanzania. The latest disease epidemic expanded to cover wider areas of the country involving both human and domestic ruminants. During the latest disease outbreak 52.4% (n=21) of regions in Tanzania mainland were affected and majority (72.7, n=11) of the regions had concurrent infections in human and animals.

Read here for more