1 Department of Virology, Aggeu Magalhães Institute (IAM), Oswaldo Cruz Foundation (Fiocruz), Avenida Professor Moraes Rego 50670-420, Recife, Pernambuco, Brazil.
2 Department of Virology, Aggeu Magalhães Institute (IAM), Oswaldo Cruz Foundation (Fiocruz), Avenida Professor Moraes Rego 50670-420, Recife, Pernambuco, Brazil. Electronic address: lindomar.pena@cpqam.fiocruz.br.