Isolation of Germiston Virus, a Hitherto Unknown Agent, from Culicine Mosquitoes, and a Report of Infection in Two Laboratory Workers

Abstract

Summary 1. Two strains of filterable virus were isolated from culicine mosquitoes collected at Germiston, Union of South Africa. One was derived from a mixed pool of 5 Culex theileri and 12 C. rubinotus and the other from a pool of 11 C. rubinotus. Results of tests reported herein indicate that the two strains are antigenically indistinguishable and the name Germiston virus has been applied in reference to the locality of origin. 2. Germiston virus is related to but not identical with Bunyamwera virus. With immune sera obtained after inoculation of laboratory animals, antigenic differences between the two viruses were easily demonstrated by HI and CF tests, less easily by neutralization test. 3. Mice immunized with Bunyamwera were not significantly protected when challenged with Germiston virus. 4. Two clinical cases of Germiston virus infection occurred in laboratory workers. Even though a significant level of Bunyamwera virus neutralizing antibody was present in sera of one of the individuals within only a few hours after onset and also in a specimen taken approximately 7 months previously, infection with Germiston virus was not prevented. The implications of this observation and results of other tests on sera from this case obtained at various time intervals are discussed. 5. Observations are presented which lead to the suspicion that birds may have had a role in infecting mosquitoes with Germiston virus.