Desenvolvimento e padronização de ensaio imunoenzimático para detecção de anticorpos contra os vírus do Oeste do Nilo e da encefalite de São Luís

Abstract

The flavivirus genus (family Flaviviridae) comprises some of the most relevant arboviruses for public health, that can cause disease in humans and animals. Some members of this Family such West Nile virus (WNV) and Saint Louis Encephalitis virus (SLEV) are antigenically related. They develop similar symptoms and their serological diagnosis may show cross reaction with other Flavivirus, present in the same geographical area. In this context, the establishment of a platform for differential serological diagnosis in these arboviruses, is crucial. Among other methodologies, the Enzyme-linked immunosorbent assay (ELISA) is the most used technique for flavivirus diagnosis, with subsequent confirmation by plaque reduction neutralization test (PRNT). Thus, the present work aimed to develop a differential immunoassay diagnostic platform for WNV and SLEV, using their structural proteins as antigens, derived from viral chimeras YFV-17D-WNV-3M and YFV-17D-SLEV respectively, previously constructed in our research group (Department of Virology, Fiocruz / PE). We analyzed 155 samples of equine sera from the state of Pernambuco-Brazil, for WNV and SLEV by blocking ELISA technique, resulting in 149 and 132 positive samples among them, respectively. All samples were tested by PRNT75 for validating the results of ELISA confirming 31 positive samples for WNV and 20 for SLEV. These results demonstrated that the platform of large-scale serological screening developed in this work is effective and has the potential use for evaluation of sera, from different species of flavivirus in Brazil.