Serologic survey of West Nile virus in horses from Central-West, Northeast and Southeast Brazil

Jaqueline Raymondi Silva,Maria Luana Cristiny Rodrigues Silva,Carlos Henrique Coelho De Campos,Larissa Campos De Medeiros,Otavio Augusto Brioschi Soares,Rosângela Zacarias Machado,Edson Elias Da Silva,Luiz Tadeu Moraes Figueiredo,Juliana Helena Chávez,Joice Lara Maia Faria,Thiago Demarchi Munhoz,Vinícius Pinho Dos Reis,Gustavo Puia Borges,Cristiane Divan Baldani

doi:10.1590/0074-0276130052

Abstract

Since the emergence of West Nile virus (WNV) in North America in 1999, there have been several reports of WNV activity in Central and South American countries. To detect WNV in Brazil, we performed a serological survey of horses from different regions of Brazil using recombinant peptides from domain III of WNV. Positive samples were validated with the neutralisation test. Our results showed that of 79 ELISA-positive horses, nine expressed WNV-specific neutralising antibodies. Eight of the infected horses were from the state of Mato Grosso do Sul and one was from the state of Paraíba. Our results provide additional evidence for the emergence of WNV in Brazil and for its circulation in multiple regions of the country.

Highlights

West Nile virus (WNV), a member of the genus Flavivirus, is responsible for large outbreaks of disease in the Old World as well as in the New World (Kilpatrick 2011)
We generated recombinant antigens consisting of domain III of WNV, Saint Louis encephalitis virus (SLEV) and Rocio virus (ROCV) in Escherichia coli (Chavez et al 2010)
All sera were tested by recombinant antigens consisting of domain III (rDIII) ELISAs specific for SLEV, ROCV and WNV

Summary

Introduction

West Nile virus (WNV), a member of the genus Flavivirus, is responsible for large outbreaks of disease in the Old World as well as in the New World (i.e., in North America) (Kilpatrick 2011). Screening of horse sera by ELISA - Domain III of the flavivirus envelope protein is known to contain the critical antigenic epitopes that react with neutralising antibodies during Flavivirus infection. All sera were tested by rDIII ELISAs specific for SLEV, ROCV and WNV. Neutralisation test (NT) - Serum samples that tested positive in the WNV rDIII-ELISA, but not in the SLEV or ROCV ELISAs, were subsequently subjected to a NT, as previously described (Hawkes 1979).

Results

Conclusion