Serodiagnosis of syphilis in a community: An evaluatory study.

PURPOSE: To analyse the prevalence of syphilis in the apparently healthy population and to provide data for implementation of the joint STD/HIV control programme, a population based study was undertaken by using 'probability proportional to size' cluster survey method in three randomly chosen districts of Tamil Nadu, India namely Dindigul, Ramnad and Tanjore. METHODS: Blood samples were collected from adults (n=1873) aged 15-45 years, from the selected households enrolled in this study. The sera were tested parallelly by rapid plasma reagin (RPR) and Treponema pallidum haemagglutination (TPHA) tests. Reactive samples by RPR and/or TPHA were later analysed by fluorescent treponemal antibody absorption (FTA-ABS) test. RESULTS: The prevalence of syphilis in the community of Tamil Nadu as per RPR positivity was 2.7% (50/1873) as against 0.7% by TPHA (13/1873). FTA-ABS positivity was observed in only 12 out of 48 (25%) RPR/TPHA reactive samples tested. By taking the positivity by two of the three tests, the community prevalence of acute ongoing syphilis in Tamil Nadu was determined as 1.1% (20/1873). CONCLUSIONS: The results confirmed that no single serological test for syphilis can act as the marker of ongoing acute infection in an apparently healthy population. The study suggests that for specific diagnosis of ongoing syphilis, the FTA-ABS test may be performed along with RPR and TPHA.

Typing of Aeromonas isolates from children with diarrhoea & water samples by randomly amplified polymorphic DNA polymerase chain reaction & whole cell protein fingerprinting.

BACKGROUND & OBJECTIVES: Aeromonas spp. are water-borne organisms, often associated with childhood diarrhoea. The present study was conducted to examine the epidemiological relationship among the Aeromonas spp. isolated from water and children with acute diarrhoea in Chennai. METHODS: Thirty six Aeromonas isolates inclusive of 16 from children with diarrhoea, 15 from domestic water samples and 5 reference strains were studied by randomly amplified polymorphic DNA polymerase chain reaction (RAPD-PCR). Twenty eight Aeromonas isolates, 15 from children with diarrhoea, 10 from domestic water samples and three reference strains were analysed by SDS-PAGE for their whole cell protein profiles. RESULTS: The 36 Aeromonas isolates examined by RAPD-PCR generated RAPD fingerprints with majority of the bands ranging from about 250 to 2800 bp. The RAPD fingerprints did not correspond with the phenospecies and varied greatly among the strains within the phenospecies. Cluster analysis revealed two major groups at 75 per cent hierarchical level, comprising 18 Aeromonas isolates, mainly recovered from domestic water samples, while the clinical isolates were scattered in different hierarchical levels in the dendrogram. The whole cell protein fingerprints examined by SDS-PAGE did not correspond with the phenospecies. Only four isolates of A. caviae were found to produce similar protein fingerprints allowing them to form a cluster at about 90 per cent hierarchical level, while the rest of the isolates were scattered at various hierarchical levels in the dendrogram. INTERPRETATION & CONCLUSIONS: In the present study, RAPD fingerprinting was found to be useful in distinguishing Aeromonas isolates recovered from clinical and domestic water supplies. However, RAPD-PCR could not distinguish the phenospecies of the genus Aeromonas. Whole cell protein fingerprinting and cluster analysis could neither differentiate isolates from clinical and domestic water sources nor the phenospecies of the genus Aeromonas.

Identification of Pneumocystis carinii in induced sputum of AIDS patients in Chennai (Madras).

Induced sputum samples were collected from 32 AIDS patients with respiratory ailments. Pneumcystis carinii was demonstrated in 9 out of 32 AIDS cases by Indirect Immunofluorescence technique (HF). Four cases were positive by all the three techniques namely Giemsa staining, Toluidine blue staining and IIF, three were positive by both toluidine blue and IIF, and two were positive only by IIF. Among other microbial pathogens, acid fast bacilli was demonstrated in all the P carinii positive cases and Candida albicans in 53% AIDS cases from the induced sputum sample.

Enhanced detection of herpes simplex virus from ocular specimens of herpetic keratitis patients.

Corneal scrapings collected from 70 patients were used to assess the diagnostic value of indirect immunofluorescence (indirect IF) procedure in comparison with routine virus culture (RVC) for the diagnosis of Herpes simplex virus induced keratitis (HSK). Virus specific antigen was detected by indirect IF in 22 (31.42%) cases. In contrast, only 20% (14) of the cases had positive viral isolation which sometimes took as long as a week to show a cytopathogenic effect (CPE). It is concluded that antigen detection by indirect IF is a rapid, specific and sensitive technique for demonstrating HSV-1 antigen in corneal scrapings from HSK patients and a useful laboratory tool not only for diagnosing HSK but also for monitoring efficiency of anti HSV treatment for HSK.