Active Circulation of Madariaga Virus, a Member of the Eastern Equine Encephalitis Virus Complex, in Northeast Brazil
Laura H. V. G. Gil, Tereza Magalhães, Beatriz Senra Álvares da Silva Santos, Livia V. de Oliveira, Edmilson Ferreira de Oliveira-Filho, João Luís Reis-Cunha, Ana Luiza Soares Fraiha, B.M.M. Rocha, Barbara Longo, Roselene Ecco, Guilherme C. Faria, Ronaldo Furtini, Safira R. M. Drumond, Renata de Pino Albuquerque Maranhão, Zélia Inês Portela Lobato, Maria Isabel Maldonado Coelho Guedes, Raffaella Bertoni Cavalcanti Teixeira, É.A. Costa
Abstract
. Disturbances in the natural transmission cycle of this virus result in outbreaks in equines and humans, leading to high case fatality in the former and acute febrile illness or neurological disease in the latter. Although a considerable amount of knowledge exists on the eco-epidemiology of North American EEEV strains, little is known about MADV. In Brazil, the most recent isolations of MADV occurred in 2009 in the States of Paraíba and Ceará, northeast Brazil. Because of that, health authorities have recommended vaccination of animals in these regions. However, in 2019 an equine encephalitis outbreak was reported in a municipality in Ceará. Here, we present the isolation of MADV from two horses that died in this outbreak. The full-length genome of these viruses was sequenced, and phylogenetic analyses performed. Pathological findings from postmortem examination are also discussed. We conclude that MADV is actively circulating in northeast Brazil despite vaccination programs, and call attention to this arbovirus that likely represents an emerging pathogen in Latin America.