The earliest reported outbreaks occurred in Kenya resulting in the death of 100,000 sheep. The 1977 Egypt outbreak affected 25.0% to 50.0% of all sheep and cattle. Among humans 200,000 fell ill, 18,000 clinical cases were confirmed with 598 deaths from haemorrhagic fevers. In 1987, RVF broke out in Mauritania following the opening of Diama Dam and resulted in more than 200 human deaths. The 1997 outbreaks in Kenya and Somalia have resulted in large losses of domestic animals, as well as, more than 300 human deaths. In September 2000, it was the first time for the disease to cross the boundaries of the African continent into Saudi Arabia and Yemen. Since then, 884 affected cases with 124 deaths in Saudi Arabia and 321 affected cases with 32 deaths in Yemen were reported.