A Study on the Resting Preference of Mosquito Species in Wells 27-31in Vellore in Tamilnadu, South India.

The resting preferences of mosquito species was investigated in domestic wells. In addition to the routine adult surveys in human dwellings, adult collections were also made in domestic wells using an innovated equipment operating on the principles of spray sheet collections. Above the water surface, wells provide humid and dark microclimate along the inner walls. It has been observed that this microclimate provides very congenial resting place for few mosquito species; specially for the males and for the females between their gonotropic cycles. Larval collections in the wells did not reveal breeding of majority of the mosquito species collected by this technique. Investigations were conducted in 87 wells in 11 localities during 2005. A total of 4969 mosquitos were collected of which 69.1 % (3441) were males and 30.9% (1528) were females. From among the mosquitos collected 96.5% were Cu.quinquifasciatus, 0.26% All stephensi, 3.0% Aedes agypti and 0.24% Armegeres sp. The results of the analysis of the physical and chemical parameter of water samples of the study wells before and after the surveys endorsed the utility of this technique for entomological investigations in outbreak situations, for monitoring the liquidation of outbreak foci and for other research purposes.

Myxoid adrenal adenoma with focal pseudoglandular pattern.

Adrenal cortical tumors with myxoid change are rare tumors. To our knowledge, only 22 cases have been described so far in literature, which include 13 carcinomas and 9 adenomas. A pseudoglandular pattern has been described in 9 of these tumors. We report a case of a myxoid adenoma of the left adrenal gland in a 67-year-old woman, with a focal pseudoglandular pattern involving about 20% of the studied tumor. Rest of the tumor was composed of anastomosing cords of tumor cells. Abundant myxoid stroma was present, which stained positively with alcian blue and was weakly focally positive with periodic acid Schiff. Immunophenotype was consistent with an adrenal tumor, i.e., positive for vimentin, inhibin, and melan A. Cytokeratin AE1/AE3 and chromogranin were negative. MIB-1 index was < 0.1%.

Serological evidence for wide distribution of spotted fevers & typhus fever in Tamil Nadu.

BACKGROUND & OBJECTIVE: Although the re-emergence of spotted fevers and typhus was documented from southern India a few years ago, there was a paucity of community based data. Therefore a collaborative study was carried out in several districts of Tamil Nadu to understand the distribution of these infections. METHODS: Blood (3 ml) was collected from patients presenting to primary health centres (PHCs) with fever >10 days duration in 15 districts of Tamil Nadu during January 2004 to December 2005. Patients negative for malaria, were tested by Weil-Felix test. Clinical data were collected from patients visiting two hospitals. RESULTS: A total 306 samples were tested in 2004 and 115 (37.5%) had titres of >or=80 with OX K antigen, suggesting a diagnosis of scrub typhus. During 2005, 964 patients were tested and 89 (9.2%) were positive for scrub typhus. An additional 44 (4.6%) were positive for other rickettsial illnesses. In both years majority of scrub typhus occurred in individuals above 14 yr of age. Cases increased from August until the earlier part of next year. INTERPRETATION & CONCLUSION: This community based study from south India involving several districts in Tamil Nadu, showed that scrub typhus and rickettsial illnesses were widely distributed in the State. Measures to increase awareness and also to diagnose and treat this infection in the affected areas are essential.

Geographical information system (GIS) in investigation of an outbreak.

An outbreak of fever in a village in southern India was reported on 1st September, 2001. The first reported case presented with epistaxis and a platelet count of 27000h(1)/mm3. Clinical, laboratory and entomological evidence supported a diagnosis of dengue fever. One third of the village was affected and 3.7 % of the population presented with haemorrhagic symptoms; none were fatal. Five acute cases tested for dengue specific IgM showed that two were positive. The larvae of Aedes aegypti were discovered from domestic water collections in the village. Spatial analysis done with the help of Geographical Information Systems software (GIS) demonstrated a centrifugal spread of cases from the most affected street until it involved the entire village. Spatial analysis revealed that cases occurred in clusters and that these could not have occurred by chance. This was our first experience in producing a geo-referenced map of a village area and in spatial analysis. GIS is a novel and simple tool for outbreak investigations and the spatial analyst adds additional information to the data collected. Control of adult mosquitoes and larvae prevented the outbreak from spreading to an adjacent village.

An outbreak of human anthrax in Mysore (India).

Anthrax is a zoonotic disease caused by Bacillus anthracis. Intestinal anthrax though a rare entity mostly ends with fatal outcome. Very few cases of intestinal anthrax are reported. Present outbreak of intestinal anthrax is unique in itself that four cases succumbed to the illness within a span of 48-72 hours in a small hamlet of Mysore district of Karnataka, after consuming diseased deer meat. Confirmation of the diagnosis was carried out at NICD, Delhi by bacteriological culture isolation, biochemical tests, animal pathogenicity and polymerase chain reaction (PCR). This outbreak clearly indicates surveillance of anthrax in animals in endemic areas is an essential part in the control of the disease with intersectoral coordination between the departments of health, animal husbandary, agriculture and forest.

Latex agglutination test in the diagnosis of pyogenic meningitis.

Samples of cerebrospinal fluid (n=204) from pediatric patients with clinically suspected pyogenic meningitis were examined by direct microscopy, bacterial culture and Latex Agglutination Test (LAT). Latex Agglutination Test was done for detection of antigen of Streptococcus pneumoniae and Haemophilus influenzae type b. Among 38 LAT positive cases, culture and/or gram stain was positive in only 20 cases and 18 cases were detected exclusively by LAT. Besides, LAT was useful in detecting the pre-treated cases as 11 out of 55 samples from pre-treated cases were positive by LAT in comparison to culture and/or Gram stain which detected only 4 of 55 cases. LAT is simple, rapid and more reliable test.

A study of dermatophytes and their in-vitro antifungal sensitivity.

Of the 150 clinically suspected cases of Dermatophytosis studied, majority of the cases were from age group 11-20 and 21-30 (51.4%), Tinea corporis (48.7%) and Tinea capitis (18%) were the commonest clinical types. The isolation rate was 24% (36) of which 19 (52.7%) were Trichophyton rubrum, 11 (30.55%) were Trichophyton mentagrophytes and 4 (11.1%) were Trichophyton violaceum. One isolate each of Microsporum gypseum & Epidermophyton floccosum were obtained. Griseofulvin proved to be the best drug with a sensitivity of 94.4% followed by Miconazole (75% sensitive). Tolnaftate showed a sensitivity of 47.22%. For Clotrimazole only 30.55% of the isolates were sensitive.

Rapid diagnosis of cholera by coagglutination test.

In this study the coagglutination test for the rapid diagnosis of cholera is evaluated in comparison with the conventional culture method. A total of 553 stool specimens were processed from cases of acute gastro-enteritis. The sensitivity and specificity of coagglutination test was 92.77% and 95.65% respectively. The coagglutination test is found to be simple, reliable and rapid method for the diagnosis of cholera.

Serotypes and phage types of Vibrio cholerae in Mysore.

A total of 565 samples of acute diarrhoeal stools from children received over a period of twelve months from November 1996 to October 1997, yielded 289 (51.15%) isolates of V. cholerae. Out of these, 277 (95.85%) were V. cholerae 01 serotype Ogawa, 7 (2.42%) were V. cholerae 0139 and 5 (1.73%) were V. cholerae non-O1 non-0139. Phage typing of the isolates was carried out by NICED Calcutta. Out of 78 isolates, 69 (88.46%) belong to phage type T27. Of the remaining, 3 (3.85%), 3(3.85%), 2(2.56%) and 1(1.28%) belong to the phage types T26, T13, T8 and T4 respectively.