First detection of Rio Negro virus (Venezuelan equine encephalitis complex subtype VI) in Córdoba, Argentina

Rio Negro virus (RNV) (Venezuelan equine encephalitis subtype VI) circulates only in Argentina; in northern provinces, isolates have been obtained from mosquitoes and rodents since 1980 and have been associated with acute febrile illness in humans. However, no studies of RNV have been performed in the central area of the country. We carried out molecular and serological detection of RNV in Córdoba, a province of the central part of the country, in mosquitoes and humans, respectively. One mosquito pool tested positive for alphavirus RNA by reverse transcriptase-nested polymerase chain reaction (RT-nested PCR). Subsequent sequencing determined that this alphavirus grouped with RNV. Serological studies detected antibodies to RNV in one human serum sample, which was obtained during the same period that RNV was detected using the aforementioned molecular methods. This is the first report of RNV circulation in the central area of Argentina, indicating an expansion of its original distribution. These results highlight the importance of strengthening surveillance procedures in endemic areas, as well as in new regions where RNV may emerge.

Prevalencia de anticuerpos VEE y EEE en población humana y equina de la selva peruana / Prevalence of antibodies VEE and EEE in human and equine population of the Peruvian jungle

El complejo de virus de encefalitis equina venezolana (VEE) esta integrado por los serotipos antigénicos 1AB, 1C,1D,1E de los cuales los únicos relacionados con epizootias son los serotipos 1 AB y IC. En el Perú el virus epizootico ha hecho su aparición esporádica desde la década de los 30, siendo la última incursión epizoodémica en el año 1973 por el serotipo 1AB. En Loreto, departamento de la Selva peruana, durante 1973 se identificó el serotipo 1D enzootico, asociado a cuadros febriles en humanos, sin embargo encuestas serológicas previas muestran anticuerpos VEE, entendiéndose que su presencia tiene una antigüedad pasada no determinada. El estudio tiene la finalidad de comparar la magnitud de la circulación de las cepas selváticas de la VEE en humanos y equinos, principalmente en las áreas tropicales donde hay una significativa población equina, considerándose este hecho de riesgo para la aparición de cepas epizooticas. Así mismo, se ha considerado también la encefalitis equina del Este (EEE), virus que ha causado epizootia equina en la selva y cuya participación en la patología humana aún no ha sido definida. Los resultados encontrados mediante prueba de neutralización en placa de VEE y EEE en células VERO con sueros humanos muestran una variada prevalencia. Siendo la mas alta para VEE en el departamento de San Martín 57 por ciento y EEE en el departamento de Loreto 62 por ciento y con relación a equinos VEE 68 por ciento y EEE 65 por ciento ambos en el departamento de Loreto.

The Venezuelan Encephalities virus (VEE) complex include 1AB, 1C, 1D, 1E serotypes, but the 1AB and IC serotypes are the only one related to epizooties. In Peru, the epizootic virus appeared in the 30th and the last appearance was in 1973 and the serotype isolated was 1AR. In Loreto in the Peruvian jungle was isolated VEE ID serotype from human febrile illness; however, previous surveillance founded VEE antibodies in the same area. In this study we want to know the prevalence of VEE and Eastern Equine Encephalities virus (EEE) antibodies in humans and equines for the jungle area where the equine population were increasing lately. U sing neutralization test by plaque reduction we founded a variety of prevalence. In the human sera the highest prevalence for VEE was 57% in San Martin and for EEE was 62% in Loreto. In equines sera the highest prevalence for VEE was 68% and for EEE was 65% in Loreto.