Endemic eastern equine encephalitis in the Amazon region of Peru.
Eastern equine encephalitis virus (EEEV) causes severe neurologic disease in North America, but only two fatal human cases have been documented in South America. To test the hypothesis that alphavirus heterologous antibodies cross-protect, animals were vaccinated against other alphaviruses and challenged up to 3 months later with EEEV. Short-lived cross-protection was detected, even in the absence of cross-neutralizing antibodies. To assess exposure to EEEV in Peru, sera from acutely ill and healthy persons were tested for EEEV and other alphavirus antibodies, as well as for virus isolation. No EEEV was isolated from patients living in an EEEV-enzootic area, and only 2% of individuals with febrile illness had EEEV-reactive IgM. Only 3% of healthy persons from the enzootic region had EEEV-neutralizing antibodies. Our results suggest that humans are exposed but do not develop apparent infection with EEEV because of poor infectivity and/or avirulence of South American strains.
Aguilar
Patricia V
PV
Center for Biodefense and Emerging Infectious Diseases, Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, Texas 77555-0609, USA.
Robich
Rebecca M
RM
Turell
Michael J
MJ
O'Guinn
Monica L
ML
Klein
Terry A
TA
Huaman
Alfredo
A
Guevara
Carolina
C
Rios
Zonia
Z
Tesh
Robert B
RB
Watts
Douglas M
DM
Olson
James
J
Weaver
Scott C
SC
D000818:Animals; D000914:Antibodies, Viral / Q000097:blood / Q000276:immunology*; D006224:Cricetinae; D003429:Cross Reactions / Q000276:immunology; D004663:Encephalitis Virus, Eastern Equine / Q000276:immunology* / Q000472:pathogenicity; D004666:Encephalitis Virus, Venezuelan Equine / Q000276:immunology* / Q000472:pathogenicity; D004683:Encephalomyelitis, Equine / Q000453:epidemiology* / Q000276:immunology / Q000517:prevention & control / Q000821:virology; D019353:Endemic Diseases; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D007114:Immunization; D008647:Mesocricetus; D051379:Mice; D009500:Neutralization Tests; D010568:Peru / Q000453:epidemiology; D016036:Seroepidemiologic Studies
D000914:Antibodies, Viral