: The overall objective of this project is to evaluate the risk of urban (epidemic) yellow fever (YF) reappearing in the Americas. Because of increasing urbanization, the abundance of the urban mosquito vector (Aedes aegypti) in most Neotropical cities, decreasing vaccine coverage, rapid transportation, and the unprecedented level of human activity in jungle areas where YF virus is endemic, there is now major concern that the epidemic or urban form of the disease will reappear in the Americas. We have recently developed a hamster model of YF, which mimics the clinical and pathological manifestations observed in severe forms of the disease in humans and monkeys. Using the hamster model, an attempt will be made to validate several of the hypotheses of why urban YF is currently absent from the Americas. There are four specific aims, which will test the hypotheses and will examine various aspects of the epidemiology of YF in the New World. These involve comparative studies of the virulence for hamsters and the infectivity for Ae.aegypti of the four major genotypes of YF virus; an investigation of the role of pre-existing heterologous flavivirus antibodies in modifying the severity of YF; and an evaluation of the importance of vertical (transovarial) virus transmission in two New World sylvan vectors (Haemagogus janthinomys and Sabethes chioropterus) in maintenance of the enzootic forest cycle. The project involves the disciplines of virology, tropical medicine, pathology, medical entomology and public health. Most of the work will be done in laboratories at the University of Texas Medical Branch, Center for Tropical Diseases; but a small portion will be done at the Evandro Chagas Institute in Belem, Brazil.
|Sbrana, Elena; Xiao, Shu-Yuan; Popov, Vsevolod L et al. (2006) Experimental yellow fever virus infection in the golden hamster (Mesocricetus auratus) III. Clinical laboratory values. Am J Trop Med Hyg 74:1084-9|
|Mutebi, John-Paul; Gianella, Alberto; Travassos da Rosa, Amelia et al. (2004) Yellow fever virus infectivity for Bolivian Aedes aegypti mosquitoes. Emerg Infect Dis 10:1657-60|
|Sbrana, Elena; Xiao, Shu-Yuan; Guzman, Hilda et al. (2004) Efficacy of post-exposure treatment of yellow fever with ribavirin in a hamster model of the disease. Am J Trop Med Hyg 71:306-12|
|Xiao, Shu-Yuan; Guzman, Hilda; da Rosa, Amelia P A Travassos et al. (2003) Alteration of clinical outcome and histopathology of yellow fever virus infection in a hamster model by previous infection with heterologous flaviviruses. Am J Trop Med Hyg 68:695-703|
|Fisher, Ann F; Tesh, Robert B; Tonry, Jessica et al. (2003) Induction of severe disease in hamsters by two sandfly fever group viruses, Punta toro and Gabek Forest (Phlebovirus, Bunyaviridae), similar to that caused by Rift Valley fever virus. Am J Trop Med Hyg 69:269-76|
|Tesh, Robert B; Arroyo, Juan; Travassos Da Rosa, Amelia P A et al. (2002) Efficacy of killed virus vaccine, live attenuated chimeric virus vaccine, and passive immunization for prevention of West Nile virus encephalitis in hamster model. Emerg Infect Dis 8:1392-7|