Venezuelan Equine Encephalitis Viruses (VEEV) in Argentina: Serological Evidence of Human Infection

María Belén Pisano,Griselda Oria,Marina Stein,Brenda Konigheim,Javier Aguilar,María Luisa Cacace,Marta Silvia Contigiani,Geraldine Beskow,Luis Aguirre

doi:10.1371/journal.pntd.0002551

Abstract

Venezuelan equine encephalitis viruses (VEEV) are responsible for human diseases in the Americas, producing severe or mild illness with symptoms indistinguishable from dengue and other arboviral diseases. For this reason, many cases remain without certain diagnosis. Seroprevalence studies for VEEV subtypes IAB, ID, IF (Mosso das Pedras virus; MDPV), IV (Pixuna virus; PIXV) and VI (Rio Negro virus; RNV) were conducted in persons from Northern provinces of Argentina: Salta, Chaco and Corrientes, using plaque reduction neutralization test (PRNT). RNV was detected in all studied provinces. Chaco presented the highest prevalence of this virus (14.1%). Antibodies against VEEV IAB and -for the first time- against MDPV and PIXV were also detected in Chaco province. In Corrientes, seroprevalence against RNV was 1.3% in the pediatric population, indicating recent infections. In Salta, this was the first investigation of VEEV members, and antibodies against RNV and PIXV were detected. These results provide evidence of circulation of many VEE viruses in Northern Argentina, showing that surveillance of these infectious agents should be intensified.

Highlights

Venezuelan equine encephalitis (VEE) is a reemerging mosquito-borne viral disease that is severely debilitating and sometimes fatal to humans [1]
Enzootic Venezuelan equine encephalitis viruses (VEEV) are increasingly recognized as important endemic pathogens of people who live near the enzootic transmission foci and/or enter the habitats where enzootic circulation occurs [1]
To begin to address this gap, we proposed to determine the occurrence of VEEV infection in humans of the North part of the country where circulation of RNV and PIXV is well known, and investigated the presence of neutralizing antibodies (NTAbs) against VEEV IAB, VEEV ID, Mosso das Pedras virus (VEEV subtype IF; MDPV), PIXV and RNV in human sera obtained during the period 2006–2011

Summary

Introduction

Venezuelan equine encephalitis (VEE) is a reemerging mosquito-borne viral disease that is severely debilitating and sometimes fatal to humans [1]. Subtypes IAB and IC are considered epidemic/epizootic varieties since they have been responsible for outbreaks involving equine and human cases [3]. These subtypes undergo an amplification cycle that involves equids, which develop high titer viremia, and mosquitoes [1]. Enzootic strains circulate in forested or swamp habitats, where rodents serve as reservoir hosts and Culex mosquitoes -mainly in the subgenus Melanoconion- act as vectors [5] These viruses have been detected in urban areas [6,7,8]. Some of these enzootic viruses are postulated to be progenitors of epizootic strains [4]

Methods

Results

Conclusion