Incidence History of West Nile Virus in Africa and Middle East, With an Emphasis on Egypt: A Review

Abstract

Importance: Since its initial isolation in Uganda in 1937 and its introduction in Egypt in 1950 through the present, West Nile virus (WNV) have had a significant global public health impact during the last decades due to their resurgence and dynamic epidemiologic features in human and animals, and its considered one of the largest arboviral neuroinvasive disease recorded in the world. Objective: To review the incidence of West Nile virus in both animals and human, with an emphasis on Egypt, to follow the preventive measures to reduce the public health impact of WNV in areas with the potential for transmission. Background: WNV has a history of irregular but recurrent epizootics in countries of Africa, Middle East and Central, Eastern and parts of southern Europe. WNV is an enveloped virus of the genus Flavivirus, is naturally maintained in an enzootic cycle between birds and mosquitoes, with occasional epizootic spillover causing sporadic cases and outbreaks of human and equine. It has recently gained considerable attention as re-emerging infections in a global scale. Environmental factors (heavy rains followed by floods, irrigation, high temperature, or mass breeding of mosquitoes) that enhance population densities of vector mosquitoes could increase the incidence of WNV infection. The disease gets its name from the West Nile District of Uganda in Africa where it was first recognized in humans in 1937. The first cases of WNV in horses were recognized in France and Egypt in the 1960’s. Since WNV is a biosafety level 3 agent, techniques that involve cell culture are restricted to laboratories with this level of biosafety, such as reference laboratories. Nevertheless, outbreaks of WNV remain unpredictable. Further coordinated studies are needed for a better understanding of the epidemiology of the virus. Conclusion: In order to fully understand the impact of WNV and/or other flavivirus infections in Egypt, epidemiology and ecological features of these agents need to established. West Nile virus has and will remain a formidable clinical and public health problem for years to come.