A primate model of respiratory syncytial virus infection.

To determine whether bonnet monkeys are susceptible to infection and disease due to respiratory syncytial virus (RSV), 4 juvenile bonnet monkeys (Macaca radiata) were inoculated with RSV intratracheally and sacrificed at 3, 5, 7 and 9 days post infection. RSV was cultured from pre-autopsy broncheoalveolar lavage fluid from all 4 animals with a peak titre of virus on day 9. Serum RSV neutralizing antibody was present by day 7. Animals developed tachypnoea and chest retractions by 5th day post infection and 2 animals had lobular pneumonia on chest radiography. The pathological changes were of a bronchovascular inflammation, interstitial pneumonia and alveolitis, akin to that seen in humans. These findings show that bonnet monkeys can be infected with RSV, and can develop immune response and clinical and pathological changes similar to those seen in human infants with RSV disease. Thus intractracheal RSV inoculation of juvenile bonnet monkeys appears to be a good model to study pathogenesis of RSV disease.

Comparison of immunofluorescence & culture for the diagnosis of respiratory syncytial virus infection.

In 809 infants and children with acute respiratory infection, HEp-2 cells were used for the isolation of respiratory syncytial virus (RSV) and an indirect immunofluorescence technique (IIF) was used for the detection of RSV antigen in the epithelial cells of nasopharyngeal secretions. While RSV was detected in culture in only 87 subjects, IIF was positive for viral antigen in 158 subjects. In children with bronchiolitis and in those with pneumonia 57 and 19 per cent respectively, had evidence of RSV infection by culture or IIF. The frequency of virus antigen detection by IIF was above 90 per cent irrespective of the duration of symptoms before specimen collection. The frequency of virus isolation in culture was 86 per cent in children with less than 2 days duration of symptoms and 42 to 69 per cent in those with duration of symptoms of 2 days or more. However, this difference was not statistically significant. In conclusion, the IIF test was not only rapid, but also more sensitive for the detection of RSV infection than culture.