RESUMO
In an attempt to determine the prevalence of certain arthropod-borne viruses of public health importance amongst the human population of the Andaman and Nicobar Islands of India, 2,401 sera were collected from six major localities. The sera were analysed by the hemagglutination inhibition (HI) and neutralization (N) tests, using Chikungunya (CHIK), Japanese encephalitis (JE), West Nile (WN), dengue (DEN-2), Langat (TP-21) and Kyasanur Forest disease (KFD) viral antigens. The highest prevalence of HI antibodies was detected against KFD virus (22.4%), followed by Langat (20.2%), JE (5.9%), DEN-2 (3.1%), CHIK (2.9%) and WN (0.8%) viruses. Cross-reactions to the viral antigens were also noted. The results of N tests indicated a high prevalence of DEN-2 (25.4%) virus, followed by Langat (17.5%), CHIK (15.3%), KFD (12%), JE (2.19%) and WN (1.8%). These results are discussed in relation to important epidemiological parameters like age, sex and geographical location. To our knowledge, this is the first report of an extensive serosurvey of arthropod-borne viruses on these islands.
Assuntos
Adolescente , Adulto , Distribuição por Idade , Anticorpos Antivirais/sangue , Infecções por Arbovirus/sangue , Vírus Chikungunya/imunologia , Criança , Pré-Escolar , Vírus da Dengue/imunologia , Vírus da Encefalite Japonesa (Espécie)/imunologia , Vírus da Encefalite Transmitidos por Carrapatos/imunologia , Feminino , Testes de Inibição da Hemaglutinação , Humanos , Índia/epidemiologia , Lactente , Masculino , Testes de Neutralização , Vigilância da População , Características de Residência , Estudos Soroepidemiológicos , Distribuição por Sexo , Vírus do Nilo Ocidental/imunologiaRESUMO
A trial with Biken Japanese encephalitis (JE) vaccine made in Japan was carried out in South Arcot district of Tamil Nadu state, India. A total of 113 school children were included in the trial. The efficacy (as determined by serological response) and safety of the vaccine were evaluated. Side effects, though minor, were noted in 54.9 per cent of the children after each dose. The serum antibody titres were determined by mouse neutralization test, plaque reduction neutralization test and haemagglutination inhibition test. An antibody response to two-dose primary vaccination schedule was observed in 72.7 per cent, whereas 87.8 per cent of the vaccines responded positively after the booster dose administered one year after. Only about 20 per cent of the children had persisting antibodies one year after the primary vaccination. The results indicated a probable need of the third dose in the primary vaccination schedule.