Outbreaks of cholera in Nepal.

This paper presents the study of the etiological agents of diarrhea in children below 14 years of age, this study was conducted from May 1995 to April 1996. One thousand one hundred seven (1,107) children with acute diarrhea receiving Oral Rehydration Therapy (ORT) at National Kanti Children's Hospital were included in this study. Stool samples of these patients were investigated at the Microbiology Laboratory, Department of Microbiology, Institute of Medicine. None of the stool samples showed the growth of Vibrio cholerae 0139 synonym Bengal. In Nepal, V.cholerae could be isolated from June to November. From December to May, no cases of V. cholerae were detected. Therefore, we address to this incidence as outbreaks rather than endemic. Mixed infections along with V. cholerae were also seen in 29% of cholera patients. V. cholerae 01, Hikojima types were the major isolates in our study followed by Ogawa type. V. cholerae, Hikojima and Ogawa serotypes were associated with mixed infection in 16.1% and 12.9% of patients, respectively. These isolates were associated with Shigella, Salmonella and pathogenic E. coli.

Seroepidemiological study of Toxoplasma infection in central and western regions in Nepal.

The present study was carried out to ascertain the seroprevalence rate in different geographical areas in Central and Western Regions in Nepal. A total of 1,237 serum samples collected from Nuwakot (217), Kathmandu valley (402) and Chitawan (159) districts in Central Region, and Mustang (143), Surkhet (64) and Banke (252) districts in Western Region in Nepal were included in this study. Toxoplasma antibodies were detected by micro-latex agglutination (MLA) and enzyme linked immunosorbent assay (IgM-ELISA) methods. The seropositive rate in Central and Western Regions were found to be 48% and 49%, respectively; with an overall positive rate of 48 percent. Districtwise, the seropositive rate in Nuwakot, Kathmandu valley, Chitawan, Mustang, Surkhet and Banke districts were 38, 46, 64, 51, 67 and 44%, respectively. Interestingly, the relatively newly inhabited Surkhet district in Western Region and Chitawan district in Central Region showed significantly higher seropositive rate compared with those of two other districts in the respective Regions (p < 0.05). Ethnically, Tibeto-Burmans showed higher seropositive rates in Central Region (p > 0.05). In contrast, Indo-Aryans showed higher seropositive rate in Western Region (p > 0.05). Age related increase in seropositivity was observed only in Central Region. One percent of Toxoplasma antibody positive samples also showed Toxoplasma IgM antibody positivity.

Seroepidemiological study of toxoplasmosis in two different geographical areas in Nepal.

A total of 302 serum samples collected from Chitawan (159) and Mustang (143) districts of Nepal were included in this study. Anti-toxoplasma antibody was detected using micro-latex agglutination (MLA) and ELISA methods. An overall positive rate was found to be 57.9%. The positive rate in Chitawan was significantly higher (64.1%) (less than 1,000 m altitude) compared to that in Mustang (51.0%) (more than 3,000 m altitude) (p < 0.05). Females in Chitawan showed significantly higher positive rate (71.2%) compared to males (56.9%) (p < 0.05). On the contrary, though insignificantly, males showed higher positive rate (57.9%) compared to that of females (43.3%) in Mustang. Almost equal positive rate was observed among males in both study area. Females in Chitawan showed significantly higher (71.2%) positive rate compared to their counterparts in Mustang (43.3%) (p < 0.001). A slight increase in positive rate with age was observed in Chitawan while in Mustang a decreasing trend was noticed. Ethnically though statistically not significant, Indo-Aryans showed a higher positive rate (69.2%) compared to the positive rate shown by Tibeto-Burmans (63.1%) in Chitawan while the reverse was true in Mustang (Tibeto-Burmans: 53.8% and Indo-Aryans: 38.4%). Interestingly, 2.9% and 1.3% of MLA positive samples showed toxoplasma IgM antibody. None of the IgM positive samples were positive for toxoplasmic antigens.

Serological study of Japanese encephalitis in Nepal.

Antibodies against Japanese encephalitis virus (JEV) were examined in 356 serum samples from individuals visiting Tribhuvan University Teaching Hospital using neutralization test. A total of 13.2% (47/356) seropositivity was observed. Antibody positivity against both Nakayama-NIH and Beijing-1 strains was seen in 7.9% subjects. Infection by Nakayama-NIH strain alone was seen to be 4.2% while 1.1% of study populations were found to be infected only by Beijing-1 strain. High antibody titer was observed in the 20-40 years age-group and did not increase with age. Seropositivity was more common in zone-A (Tarai) area compared to zone-B (Hills) and zone-C (Mountains). Spectrum of antigenicity of JEV in zone-A as shown by neutralization test was identical to Indian isolates (strains). Difference in seropositivity was observed against Nakayama-NIH and Beijing-1 strain in zone-B and C indicating recent spread of JEV in these areas.

Seroepidemiological study of herpes viruses in Nepal.

The antibody positive rates among Nepalese, in a community, to herpes simplex virus (HSV), varicella-zoster virus (VZV) and cytomegalovirus (CMV) were studied. Immune adherence hemagglutination test (for VZV) and complement fixation test (for HSV and CMV) were used to measure the antibodies. An 80% positive rate of anti-HSV antibodies was found in early childhood (1-4 years) that further increased with age (96.1% positive in greater than 15 years age). Only 25% of children 1-4 years old showed antibodies to VZV but the number of positives increased rapidly with age (82.9% in greater than 15 years age). Antibody against CMV was positive in all the subjects studied.