Genomic Characterization and Seroprevalence Studies on Alphaviruses in Uruguay

A. BURGUEÑO; A. BURGUEÑO, S. FRABASILE, LA. DIAZ, A. CABRERA, MB PISANO, ME RIVAROLA, M. CONTIGIANI, A. DELFRARO; LA DIAZ; A. CABRERA; MB PISANO; ME RIVAROLA; M. CONTIGIANI; A. DELFRARO

AMERICAN JOURNAL OF TROPICAL MEDICINE AND HYGIENE

AMER SOC TROP MED & HYGIENE

Lugar: Stanford; Año: 2018 vol. 98 p. 1811 - 1818

0002-9637

Alphaviruses (Togaviridae) are arboviruses frequently associated with emerging infectious diseases. In this study, we aimed to investigate the presence of alphaviruses in Uruguay by detecting the viral genome in mosquitoes and neutralizing antibodies in equines. A total of 3,575 mosquitoes were analyzed for alphavirus genome detection. Serologicstudies were performed on 425 horse sera by plaque reduction neutralization test (PRNT80) against Venezuelan equine AU4 encephalitis virus (VEEV) subtype IAB, Pixuna virus (PIXV), Rio Negro virus (RNV), western equine encephalitis virus(WEEV), and Madariaga virus (MADV). Mosquitoes belonging to six genera were captured and 82.9% were identified as Culex pipiens. Two Cx. pipiens pools collected in Fray Bentos and Las Toscas localities were alphavirus positive, andphylogenetic analyses showed that the sequences grouped into two different clusters: the lineage I of eastern equine encephalitis virus and RNV (VEEV complex), respectively. Plaque reduction neutralization test assays showed antibodies against strains of the VEEV complex, MADV, and WEEV. Rio Negro virus was the most geographically widespread virus,showing higher seroprevalences (up to 20%). Seroprevalences against VEEV IAB ranged between 4.6% and 13%; antibodies against PIXV, WEEV, and MADV were less frequent (3?4%). In conclusion, RNV exhibited the highest sero-prevalence in horses, a wide geographical distribution, and viral genome was detected in Cx. pipiens mosquitoes. Madariaga virus had a low seroprevalence in equines, but an epizootic lineage typical of North America was detected in Cx. pipiens mosquitoes. Taken together, our results show that alphaviruses are present in Uruguay with variable oc-currence and geographical distribution being a potential threat for human and equine health.