1 Arbovirus Reference Branch, Division of Vector-Borne Viral Diseases, Center for Infectious Diseases, Centers for Disease Control, Public Health Service, U.S. Department of Health and Human Services, Fort Collins, Colorado 80522
* Arbovirus Section, Laboratory of Virology, National Institute of Health and National School of Public Health, 1699 Lisbon, Portugal
Prototype Thogoto virus from Kenya and Thogoto virus isolates from Portugal, Italy, Nigeria, Central African Republic, Cameroon, and Iran were cross-tested by hemagglutination inhibition and serum dilution plaque reduction neutralization. Considering the broad geographic distribution of these strains, the antigenic differences seen appear to be essentially minor. This uniformity suggests that the distribution of Thogoto virus is due to repeated introduction of virus from common sources and that such introduction may depend on the movement of tick-infested domestic animals.