Virus Zinga strains have been isolated from several pools of mosquitoes collected in Perinet area, 130 km far from Tananarive, at the Institut Pasteur of Madagascar in 1980. Although this virus is pathogenic for man, it seemed to give only a mild illness and did not appear to constitute a problem of Public Health. But today it is seen in quite a different way; since the WHO Center for Arbovirus Reference and Research of New Haven has shown the serologic identity between virus Zinga and an another arbovirus, Rift Valley Fever virus. This latter is in fact very pathogenic for man and domestic animal, he is responsible of important epizootics characterized by many abortions in pregnancies and death of newborn animals, many infections have occurred in man during these epizootics and the disease is able to give a mortal haemorragic syndrome. Until now, no particular aggressivity has been shown by virus Zinga in Madagascar, but it remains a real potential danger for man and for domestic animals.