Serological and virological studies of Japanese encephalitis in the Terai region of Nepal.

In 1987 and 1990, serum samples were collected from people living in the two districts (Itahari and Chitwan) of the Terai region of Nepal. Antibodies against Japanese encephalitis (JE) virus in these sera were detected by the hemagglutination inhibition (HI) and neutralization (N) tests. By the HI test, 26 out of 172 (15.1%) sera from Chitwan and 15 out of 137 (10.9%) sera from Itahari showed positive titers. Higher positive rates were shown by the N test, where 46 out of 172 (26.7%) sera from Chitwan and 22 out of 137 (16.1%) sera from Itahari had antibodies against JE virus. A JE strain was isolated from a blood specimen of a pig raised in Kathmandu. When the nucleotide sequence of the pre-M region of the strain was compared to the same region of the other JE virus strains reported, the highest similarity was observed to the strains isolated in Nepal in 1985. These results suggest that the Terai region has been an epidemic area of JE.

Laboratory diagnosis of congenital and maternal rubella infection: a review.

Physicians are aware of the congenital rubella syndrome. Serodiagnosis is usually used to detect rubella infection in pregnant women and their fetuses. Although being considered the cornerstone of serodiagnosis, the hemagglutination inhibition test is gradually being replaced by new more convenient methods. Tests to detect IgM eliminate the need for paired sera to diagnose acute rubella infection. However, because of the possibilities of false positive, IgM results should be interpreted with caution. Detection of IgM in cord blood and new genetic technology made the diagnosis of infection in utero possible. The evidence of reinfection in people considered to be immune is abundant; however, discovering new antigenic determinants correlating with immunity may solve the problem and a new vaccine and antibody test that is truly associated with immunity will be available in the future.