Rotavirus infection among infants and young children in Chennai, South India.

BACKGROUND: Group A rotavirus has been recognized as the major etiologic agent of childhood gastroenteritis in infants and young children worldwide. Rapid progress towards the development of an efficacious rotavirus vaccine has warranted extensive epidemiological studies on rotavirus serotypes that cause severe disease in developing and developed countries and to monitor the emergence of newer and unusual strains in different geographical settings that could represent variants not covered by existing vaccines. METHODS: In this study, we determined the prevalence of rotavirus infection and characterised group A rotavirus in stool samples by using monoclonal antibody (MAb) based ELISA and polyacrylamide gel electrophoresis (PAGE). Stool samples were collected from 745 children of 0-3 years of age presenting to the hospital with acute diarrhea between March 1995 and August 1999. These were assayed for antigenic (group, subgroup, serotype) and genomic (viral RNA profile and VP7 and VP4 genotype) characterization by ELISA and PAGE. RESULTS: Out of 745 stool samples analysed 168 were found to be positive for rotavirus. Among these 118 could be assigned a subgroup (SG), serotype and electropherotype (E-type). The study has evidenced the predominant occurrence of strains with short E-type, SGI and serotype G2 in 66.1% of the samples. The presence of strains representing 10 different E-types and mixed genotype specificities with G2 P[4,8] and G1-G2 P[4,8] has documented the prevailing high genomic diversity of rotaviruses in this geographical area. CONCLUSION: This study has described the predominant strains of rotavirus in south India. There is a need for further detailed studies on the molecular characterization of rotaviruses which would have important implications in vaccine evaluation programmes.

Role of coccidian parasites in causation of diarrhoea in HIV infected patients in Chennai.

BACKGROUND & OBJECTIVES: Diarrhoea is one of the major problems of HIV positive patients. A coproparasitological study was carried out to assess the role of coccidian parasites in the causation of diarrhoea in HIV infected patients in Chennai. METHODS: During May 2000 to January 2001, 152 stool samples from HIV seropositive individuals (43 with acute diarrhoea, 59 with chronic diarrhoea, 50 without diarrhoea) and 50 normal individuals without diarrhoea were examined for enteric coccidian and other intestinal parasites by microscopy and special staining methods. RESULTS: A total of 52 enteric parasites, 15 from patients with acute diarrhoea and 24 from patients with chronic diarrhoea, 7 from patients infected with HIV without diarrhoea and 6 from normal individuals without diarrhoea were detected from 49 patients. Isospora belli was detected in 14 of 102 (13.7%) patients with acute and chronic diarrhoea. The association with diarrhoea among HIV positive individuals was significant (P < 0.001). Cryptosporidium was detected in 7 patients each with acute and chronic diarrhoea and 4 patients with HIV infection without diarrhoea, its association with diarrhoea among HIV patients was found to be not significant in the present study. Cyclospora and Microsporidia each were detected in only one HIV positive patient with chronic diarrhoea. INTERPRETATION & CONCLUSION: The study revealed that the coccidian parasites are one of the important etiologic agents of diarrhoea (P < 0.001) especially of chronic diarrhoea among HIV positive patients. Isospora belli was found to be a frequent enteric parasite associated with diarrhoea among HIV positive patients in Chennai.

Stiff person syndrome and myasthenia gravis.

Association of stiff person syndrome, an immune related disorder of anterior horn cells and myasthenia gravis an endplate disorder with similar pathogenesis, is rare. This communication documents this association in the Indian literature for the first time.

Stiff person syndrome.

This communication considers a patient with episodic muscle spasms. Pharmacological intervention and electrophysiological studies provided adequate evidence confirming the diagnosis of stiff person syndrome. Electrophysiological studies in present communication similar to earlier reports, confirmed once again the autonomous state of the anterior horn cell in this disease process.

Comparative analysis of monoclonal antibody based enzyme immunoassay, modified genome electrophoresis & electron microscopy procedures for rotavirus diagnosis from faecal specimens.

BACKGROUND & OBJECTIVES: Reliable and rapid diagnosis of rotavirus infection is necessary for patient management. Several newly introduced commercial enzyme immunoassays (ELISAs) have been evaluated using direct electron microscopy (DEM) with or without direct ultracentrifugation as the standard reference method, and have shown varying results. METHODS: In the present study we compared the diagnostic efficacy of the three methods viz., monoclonal antibody (MAb) ELISA, modified polyacrylamide gel electrophoresis (PAGE) and DEM without ultracentrifugation in the detection of rotaviruses from 211 stool specimens. The data were analysed by two latent class model (2LC) in the absence of a gold standard reference method. RESULTS: Rotavirus was detected in 42 specimens by MAb-ELISA; in 40 specimens by PAGE and in 33 specimens by DEM. The estimates of sensitivities and specificities of the three methods were analysed by 2LC method. The analysis revealed no significant variation among the three methods. However, DEM was found with a comparatively lesser sensitivity over the other two methods. INTERPRETATION & CONCLUSIONS: Though DEM was found to be relatively less sensitive than the other two methods, the differences were not significant, and all the three methods were highly specific. Moreover, DEM has the additional advantage of detecting non-group A and other gastroenteritis viruses. The findings suggest the use of highly sensitive and specific MAb-ELISA and PAGE in parallel to detect group A, non-group A and atypical rotavirus infection in the population.

Genomic diversity of group A rotavirus RNA from children with acute diarrhoea in Chennai, south India.

Group A rotavirus was identified in 51 of 245 (20.8%) cases with acute diarrhoea in Chennai analysed between December 1997 and March 1999. Forty eight of the 51 specimens were subgrouped and serotyped. A total of 110 rotavirus positive specimens (inclusive of 62 rotavirus positive cases reported earlier) were analysed for their subgroup (SG) specificity and genomic profiles. SGI and SGII specificity were detected in 60 per cent and 20 per cent of the cases studied. Twenty two cases showed dual SG specificity (SGI + II). Nine electropherotypic patterns (7 'short' and 2 'long') were observed with a predominance of short pattern in 87 of the 110 (79.1%) positive cases studied. Long electropherotypes were found in 23 (20.9%). Serotyping of the 48 rotavirus positives revealed a higher proportion of serotype-2 (68.8%) followed by serotype-1 (14.6%) and serotype-3 in 1 case. Mixed infection of G1-G2 was observed among 7 cases analysed, which revealed G[2,1], P[4,8] genotype specificity. Dual infection of P[4]-P[8] genotypes was observed in 12 cases with G[2] specificity.

Analysis of human rotavirus serotypes in children with acute diarrhoea in Chennai by monoclonal antibody based ELISA.

To determine the individual human rotavirus serotypes prevailing in Chennai, 345 stool specimens obtained from children with acute diarrhoea between March 1996 and November 1997, were screened for the presence of rotavirus by the standardized enzyme linked immunosorbent assay (ELISA). Of the 90 (26%) rotavirus positive specimens, 75 (83.3%) were subgrouped and 65 (72.2%) were serotyped with monoclonal antibody based ELISA. Of the 65 specimens that could be serotyped, 52.3 per cent belonged to serotype 2, 24.6 per cent were serotype 4, 15.4 per cent were serotype 1 and 7.7 per cent were serotype 3. Of the 75 specimens typed for their subgroup specificity, 50.7 per cent were subgroup I, 26.7 per cent were subgroup II, 18.7 per cent were equally specific to both subgroups I and II, 4 per cent belonged to nonsubgroups I and II. Our results indicate a predominance of serotype 2 virus. Unusual strain having both subgroups I and II specificity or neither specificity were also encountered.