The Extended Horizons of Rift Valley Fever: Current and Projected Immunogens
ARMY MEDICAL RESEARCH INST OF INFECTIOUS DISEASES FORT DETRICK MD
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The first detailed description of Rift Valley Fever RVF was based on a sheep epizootic in an area where the great Rift Valley runs through Kenya. RVF is a viral disease causing arthropod-borne epidemics of domestic animals during which man is also infected. Sheep epizootics resembling RVF occurred in Kenya during the first two decades of the 20th century, but it was not until 1930 that Daubney and coworkers studied the disease in detail and established the viral etiology of RVF. Initial scientific progress was rapid. Field operations and laboratory studies revealed that a a wide variety of domestic, wild, and laboratory animals were susceptible to RVF virus infection with the characteristic pathological lesion being focal liver necrosis b the virus could be isolated from, and transmitted by, a number of mosquito species and c many African nations had serological evidence of human or animal infection by RVF virus. The disease continued to cause periodic epizootics, but until 1977 it was geographically limited to Sub-Saharan Africa. During many epizootics and as a result of numerous laboratory infections, human RVF was described a a mild, dengue-like, febrile illness. However, during the 1975 epizootic in South Africa, severe clinical disease was reported in a small number of people, and the first fatalities directly attributable to RVF were documented. In 1977, an outbreak of the disease ws reported in the Nile delta, a new geographic area and extensive human involvement with numerous fatalities occurred during the epizootic. The Egyptian epizootic re-emphasized the importance of this disease, as well as our lack of detailed understanding of the epidemiology, virology and pathogenesis of RVF. It also served as a graphic example of the potential of RVF to circulate in a number of differing geographic and climatic settings, since the virus has now spread in a 7,000-km north-south range throughout Africa. Although we do not know whether the virus will...
- Medicine and Medical Research