Immunity to Certain Arthropod-Borne Viruses Among Indigenous Residents of Egypt

Abstract

Summary Sera from indigenous residents of ten widely scattered localities in Egypt were tested for capacity to neutralize ten different viruses, each known or believed to be arthropod-borne. The following results of significance were obtained. 1. Immunity to West Nile virus is very prevalent in all localities sampled except Damietta. Immunity is frequently acquired very early in life. Many sera neutralized this virus and no other. 2. Protective antibody against Ntaya virus was demonstrated in 34.9 per cent of all sera tested. Protective antibody against this agent was commonly associated with capacity to neutralize one or more other viruses, particularly West Nile. A few sera neutralized Ntaya virus alone. The only locality showing no immunes was Damietta. 3. Twelve of 143 sera neutralized Japanese B virus, but since the same sera also neutralized West Nile and Ntaya viruses, this result cannot be interpreted at present. 4. A few sera neutralized Uganda S, St. Louis encephalitis, Bunyamwera, Zika, and Semliki Forest viruses, but the results do not indicate that these agents are medically important in any of the localities concerned. 5. None of the sera tested against Bwamba fever or yellow fever viruses neutralized these agents.