Blood of the Lambs:How new dams in Africa cause lethal epidemics of Rift Valley Fever (Blue Nile Monograph, Four)

Dam designers and builders should take note that lethal epidemics of the mosquito-borne Rift Valley Fever have accompanied the first-filling of new dams in northern Africa during the last several decades. The first epidemic occurred around the enormous Aswan Dam on the Nile River in 1977, and the plague appeared again in 1987 when three new dams in the Senegal River basin in West Africa filled for the first time. It was reported that over 600 people died of Rift Valley Fever at Aswan, and that over 200 died around the three dams in West Africa, due to the same fever. Probably the number of deaths was much higher, due to chronic under-reporting of diseases in both areas. In October 1977 it was found that the lethal hemorrhagic fever which struck at Aswan, was caused by a virus spread by floodplain mosquitoes. It had been an extremely wet rainy season in the Nile River Valley, provoking flooding in low areas and resulting in hordes of mosquitoes around villages, towns and cities along the river. Filling of the lake was coincident that year with the Muslim Feast of the Sacrifice, known as Eid el Adha in Arabic, in which large numbers of sheep are involved. These sheep can carry the virus of Rift Valley Fever which causes abortions and deaths in the flocks. The virus, spread by mosquitoes and ticks, can also be spread to other animals - including humans.