Serological response to Japanese encephalitis vaccine in a group of school children in South Arcot district of Tamil Nadu.

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.

Viruses in acute gastroenteritis in children in Pune, India.

A 2-year study from January 1981 to December 1982 was undertaken to determine the role of viruses in the causation of diarrhoea in hospitalized children in Pune, Maharashtra State, India. The stool samples of 426 children (213 diarrhoeal and 213 non-diarrhoeal controls) were investigated by electron microscopy and ELISA for the presence of viruses. Six morphologically distinct viruses were visualized: rotavirus, coronavirus-like particles (CVLP), adenovirus, astrovirus, calicivirus and small round virus-like particles (SRV). Rotavirus was detected in 28.6% of the diarrhoeal patients and in 1.4% of the controls. The frequency of infection with rotavirus was highest in the children aged less than 5 years. The mean age of rotavirus-positive patients was 11 months. Although rotavirus was detected in almost every month, there has a seasonal trend for colder months when CVLP cases were fewest. However, the prevalence of CVLP was greater in the control group (23.0%) rather than in those with diarrhoea (8.9%). In the control group, CVLP were detected more frequently during the summer months. An inverse relationship between CVLP and rotavirus was observed in children. Adenovirus, astrovirus, calicivirus and SRV were detected in a small proportion of children with and without clinical symptoms of gastroenteritis.

Screening for AIDS in western India: transfusion aspects.

Screening of blood donations for anti-HIV in western India has shown a rising trend of antibody-positive donors. There was a statistically significant difference between the proportion of positive reactors before 1986 and after 1986 (p less than 0.05).

Sero-surveillance for HIV infection in India.

PIP: The collaborative efforts of the Ministry of Health and Family Welfare of the Indian Government, the Indian Council of Medical Research, and the State Government Health Services have produced a sero-surveillance program for HIV infection in India. Through mid-October, 1987, the program's 36 surveillance centers identified 145 seropositive individuals, and 13 with AIDS, out of a total screened pool of 56,934 considered to be at high-risk of HIV infection. 2/3 male, and 20-30 years, screened individuals were largely blood donors and heterosexually promiscuous men and women seen at STD clinics. Relatively few prostitutes, homosexuals, and IV-drug users have been tested. Health education, counseling, and periodic health check-ups are stressed for all asymptomatic, sero-positive individuals. Overall, sero-surveillance suggests a low prevalence of HIV infection in India even among high risk groups. Heterosexual transmission is the main mode of infection in India, with perinatal exposure to HIV, and transfusions also documented as transmission sources. The screening of blood products for HIV antibodies has been made mandatory by the government of India.^ieng

Seroepidemiological investigations on human immunodeficiency virus infections in some parts of India.

PIP: 2597 serum samples from individuals belonging to various groups were screened for antibodies to human immunodeficiency virus (HIV). The majority of the sera screened were from residents of India; 16 were from foreigners. Screening was done using ELISA kits from 4 different commercial sources. Samples which were reactive initially were retested using the same kit. 4 samples were reactive repeatedly in all the kits used. 2 of these were from patients with Acquired Immune Deficiency Syndrome (AIDS), 1 from a patient with AIDS-related complex, and 1 from an apparently healthy female prostitute living in Bombay. These 4 samples were confirmed to be positive by Western Blot, immunofluorescence, and the Karpas AIDS test. Among the sexually promiscuous persons screened for antibodies to HIV in India, female prostitutes appear to be the only risk group in whom antibodies to HIV virus have been detected. This also has been reported from Tamil Nadu. Positive reactors among blood donors screened even in areas of high incidence of AIDS has been very low. There were no positive reactors among the tribals, naval personnel, and individuals from jails. Overall, the data and an earlier report from Delhi suggest that the activity of AIDS retrovirus remains low in India, but the possible threat of spread of this disease should be considered. As prostitutes have been the only risk group with positive serological evidence of HIV infection, surveillance of this group is indicated.^ieng

Aetiological association of a virus-like particle with enterically transmitted non-A, non-B hepatitis.

Virus-like particles, approximately 27 nm in diameter, were identified in faeces from an Indian patient with enterically transmitted non-A, non-B (ENANB) hepatitis. They were serologically distinct from hepatitis A virus (HAV). Nucleic acid extracted from the particles did not hybridize with cDNA probes representing the genomes of HAV, enteroviruses, and cardioviruses. Chimpanzees were experimentally inoculated with faecal suspensions containing this 27 nm particle or with faeces from another case of ENANB hepatitis. Mild histological and biochemical hepatitis developed in these animals and there was serological evidence of infection with the virus-like particle as shown by immunoelectronmicroscopy (IEM). Serological analysis by IEM suggested that this agent or an antigenically similar virus was the aetiological agent of two epidemics and a sporadic case of ENANB hepatitis in India and of an epidemic of the illness in the USSR. Antibody to the particle was found in sera from patients with ENANB hepatitis from various geographic areas over a 30-year period.

Absence of viraemia in cattle after experimental infection with Japanese encephalitis virus.

Cow calves were infected with Japanese encephalitis virus (JEV) by parenteral inoculation. One batch was reinfected with JEV, followed by West Nile virus (WNV), while another batch was reinfected directly with WNV. No viraemia due to either JEV or WNV was demonstrated in any of the calves. Culex tritaeniorhynchus mosquitoes fed on 4 of the calves infected with JEV during the first 10 d had no detectable virus, nor did they transmit the virus by bite to susceptible baby chickens. In another experiment, calves did not develop viraemia after infected C. tritaeniorhynchus mosquitoes were allowed to feed on them. Neutralizing and/or haemagglutination-inhibiting antibodies against JEV were demonstrated in 6 of the 11 calves, which explains the high proportion of JE seropositives among cattle in India. All the 5 calves that were infected with WNV subsequent to JEV developed neutralizing and haemagglutination-inhibiting antibodies against WNV also. The study indicates that cattle do not play a role in the maintenance of JEV in nature.

Persistence of rabies antibody 5 years after pre-exposure prophylaxis with human diploid cell antirabies vaccine and antibody response to a single booster dose.

In 1978, 22 staff members of the National Institute of Virology, Pune, India, were given two doses of human diploid cell antirabies vaccine (HDCV) for primary pre-exposure prophylactic immunization; the interval between the two doses being approximately 4 weeks. Eighteen of these 22 vaccinees were given a booster dose 1 year later. All 18 vaccinees developed protective levels of antibody; most of them had antibody levels exceeding 10 IU/ml. In 1984, 5 years after the booster dose, 11 (79.0%) of 14 vaccinees tested still possessed neutralizing antibody levels ranging from 0.5 IU/ml to 10 IU/ml. Fourteen days after the administration of a booster dose, the antibody levels ranged from 10 to greater than or equal to 100 IU/ml for all except one vaccine (5.2 IU/ml). These findings demonstrate that the majority of vaccines retained detectable neutralizing antibody after pre-exposure prophylaxis for as long as 5 years and that a single booster dose thereafter evoked a good antibody response.

Alteration in immune response of mice with dual infection of Toxocara canis and Japanese encephalitis virus.

Concurrent dual infections of mice with Toxocara canis and Japanese encephalitis virus (JEV) showed a distinct synergistic effect of the parasite on sublethal JEV infection. Dose-dependent effects were evident in the mice infected dually and with T. canis alone; leucocytosis with suppression of eosinophilia in the peripheral blood and reduction in migration inhibition factor produced by spleen cells in response to T. canis and JEV antigens were recorded, particularly in the former group. These changes were accompanied by reductions in both antibody response to sheep erythrocytes and T cell numbers in the spleen. No appreciable changes were recorded in the mice infected with JEV alone. Thus, the T cell immuno-suppression induced by T. canis might have triggered the viral encephalitis caused by JEV in the dual infections.

Horizontal transmission of hepatitis B virus infection in household contacts, Pune, India.

The study was undertaken to detect the risk of infection, if any, among 193 household contacts of 40 hospitalised hepatitis patients (group I) with hepatitis B surface antigen (HBsAg) in their blood. As a control group, 103 household contacts of 27 hospitalised hepatitis patients who were negative for HBsAg (group II) were investigated. The family contacts of the former group had a significantly higher prevalence of HBV infection than those of the latter group (P less than .001). Significant differences were observed both in the prevalence of HBsAg (P less than .05) and antibody to HBsAg (anti-HBs) (P less than .025) between the two groups. IgM antibody to hepatitis B core antigen (anti-Hbc-IgM) was detected in 32 out of the 39 (82%) sera tested from the patients of group I with HBsAg. A statistically significant difference (P less than .005) of HBV prevalence was also found in the contacts of these 32 patients suffering from acute hepatitis B as compared to the contacts of the patients of group II. Overall, the children of the first group showed a significantly higher prevalence of HBsAg as compared to the second group. All the children with HBsAg were positive for HBeAg also, but were negative for anti-HBc-IgM. Anti-HBs was detected in a significantly larger number of adult females. Spouses were found to be affected more than other relatives. A significant difference (P less than .025) was noted in the number of families having HBV markers in group I (80.0%) as compared to those in group II (48.1%).(ABSTRACT TRUNCATED AT 250 WORDS)