First isolation of West Nile virus in Brazil

BACKGROUND Serological evidence of West Nile virus (WNV) infection has been reported in different regions of Brazil from equine and human hosts but the virus had never been isolated in the country. OBJECTIVES We sought to identify the viral etiology of equine encephalitis in Espírito Santo state. METHODS We performed viral culture in C6/36 cells, molecular detection of WNV genome, histopathology and immunohistochemistry from horse cerebral tissue. We also carried out sequencing, phylogenetic analysis and molecular clock. FINDINGS Histopathologic analysis from horse cerebral tissue showed injury related to encephalitis and WNV infection was confirmed by immunohistochemistry. The virus was detected by reverse transcription quantitative polymerase chain reaction (RT-qPCR) from brain tissue and subsequently isolated in C6/36 cells. WNV full-length genome was sequenced showing the isolated strain belongs to lineage 1a. The molecular clock indicated that Brazilian WNV strain share the same common ancestor that were circulating in US during 2002-2005. MAIN CONCLUSIONS Here we report the first isolation of WNV in Brazil from a horse with neurologic disease, which was clustered into lineage 1a with others US WNV strains isolated in beginning of 2000’s decade.

Bibliographic Details

Main Authors:	Martins,Lívia Caricio, Silva,Eliana Vieira Pinto da, Casseb,Livia Medeiros Neves, Silva,Sandro Patroca da, Cruz,Ana Cecília Ribeiro, Pantoja,Jamilla Augusta de Sousa, Medeiros,Daniele Barbosa de Almeida, Martins Filho,Arnaldo Jorge, Cruz,Ermelinda do Rosário Moutinho da, Araújo,Marialva Tereza Ferreira de, Cardoso,Jedson Ferreira, Cunha,Marcos Antônio Correia Rodrigues da, Almada,Gilton Luiz, Romano,Alessandro Pecego Martins, Santos,Maria Guadalupe Dias Pestana, Rodrigues,Gilsa Aparecida Pimenta, Chiang,Jannifer Oliveira, Quaresma,Juarez Antonio Simões, Carvalho,Valéria Lima, Vasconcelos,Pedro Fernando da Costa
Format:	Digital revista
Language:	English
Published:	Instituto Oswaldo Cruz, Ministério da Saúde 2019
Online Access:	http://old.scielo.br/scielo.php?script=sci_arttext&pid=S0074-02762019000100305
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