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S C Tewari

Publications and source records attributed to S C Tewari.

At least 19 recordsLinked to original sources
PubMed2003

Longitudinal studies in South Indian villages on Japanese encephalitis virus infection in mosquitoes and seroconversion in goats.

Japanese encephalitis (JE) is endemic in Cuddalore district, Tamil Nadu, where Culex tritaeniorhynchus Giles was the major vector. We screened 45 100 adult female Cx. tritaeniorhynchus (902 pools) by enzyme-linked immunosorbent assay and isolated and confirmed JE virus (JEV) by using an insect bioassay system. We had 69 isolates of which 62 (90%) were identified as JEV. The average vector abundance per man hour for Cx. tritaeniorhynchus was 324.5 per month for the period June 1998-May 2000. The average minimum infection rate (MIR) per month in Cx. tritaeniorhynchus was 1.4 (range 0.0-5.6). Every year, a new batch of goats, 20 in the first year and 31 in the second year, born during the non-JE transmission period (January-June), aged <6 months and negative for haemagglutination inhibition (HI) antibodies were procured and placed in the villages as sentinels. Fortnightly, blood specimens were collected from these goats and tested for JE antibodies by HI test. Seroconversions (SCs) were recorded in 14 goats (70%) in the first year and 23 goats (74%) in the second year. JE HI antibody titres in goats were low (1:10-1:80) and these levels declined to undetectable levels in about 4 weeks following SCs. The time sequence of events indicated that four of five peaks of MIR in mosquitoes were followed 1-3 months later by peaks in the proportion of seroconverted goats. We suggest the screening of goats and cattle as a more feasible tool to stratify areas according to JE infection risk to the human population through the regular health system rather than screening mosquitoes using monoclonal antibodies, which is possible only in specialized laboratories.

Animals↗
PubMed2002

Resurgence in filarial transmission after withdrawal of mass drug administration and the relationship between antigenaemia and microfilaraemia--a longitudinal study.

Seven village units endemic for filariasis were assigned randomly into three arms with different intervention strategies in the years 1995 and 1996. Villages in Group A received two annual mass drug administrations (MDAs) of diethylcarbamazine (DEC) plus ivermectin (IVR). Group B received the same MDAs in combination with vector control; in Group C only placebo was administered. Post-treatment evaluation in 1997 revealed marked reductions in microfilaraemia prevalences (MFP) and geometric mean intensities (GMI). Subsequently, vector control in Group B was continued by the community. Groups A and B received no MDAs between 1997 and 1999 and were re-evaluated in 1999. During this evaluation, antigenaemia prevalence (AGP) was estimated along with MFP, using immunochromatographic test (ICT) kits. The gains of the MDAs were sustained in Group B, while resurgences occurred in Group A, where annual transmission potential (ATP) rose from 21 to 631.6 and MFP doubled. Group C continued to have high ATPs (1057-1617), while Group B had very low ATPs (0-63). After Mulla's corrections, the reductions in MFP were 62.7 and 83.5% and for GMI 72.1 and 91.4% in Group A and B, respectively, compared with Group C. Vector control preserved the gains of MDAs and accounted for 55.8% and 67.1% reductions in MFP and GMI in Group B compared with Group A. The reductions in AGP were 29.4% in Group A and 39.2% in Group B against Group C. The differences between MFP and AGP were nearly uniform across all villages and there was a significant correlation (r=0.98) between the two variables. A similar significant relationship was observed between MFP and AGP values across age groups (r=0.95). Prediction of AGP values from MFP values was proposed with regression equations. We conclude that vector control would be useful as an adjuvant to chemotherapy to prevent resurgences.

Adolescent↗
PubMed2001

Neutralizing and complement-fixing monoclonal antibodies as an aid to the diagnosis of equine herpesvirus-1 infection.

One complement-fixing (C-MAb) and three complement-dependent neutralizing monoclonal antibodies (N-MAbs) were raised against Hisar-90-7 equine herpesvirus-1 (EHV-1) strain. The target antigen of the C-MAb (2A5) and two of the N-MAbs (1H6, 9C4) was identified as a 140 kDa polypeptide in Western blotting. The target antigen of N-MAb (9C6) could not be identified. Purified polypeptides of five EHV-1 strains isolated from different regions and at different times gave intense bands at 140 kDa when reacted with N-MAb (1H6) in Western blots. In sandwich ELISA, all four MAbs captured the viral antigen from clinical materials, giving a reliable and rapid diagnosis of EHV-1 infection in equines.

Animals↗
PubMed2001

Annual single-dose diethylcarbamazine plus ivermectin for control of bancroftian filariasis: comparative efficacy with and without vector control.

Two intervention strategies for the control of bancroftian filariasis were compared in rural villages of southern India: annual mass treatment with single-dose diethylcarbamazine plus ivermectin, either on its own or combined with vector control. Vector control, based on the use of polystyrene beads and larvivorous fishes in the major breeding sites of Culex quinquefasciatus, brought about a drastic and sustained reduction in vector density and man-biting rates. After the first round of treatment, chemotherapy alone brought about a 60% drop in the annual transmission potential (ATP) whereas the integrated strategy reduced ATP by 96% (P < 0.05). After two annual rounds of treatment, the reduction in ATP was similar for both strategies (91%-96%), with the prevalences of microfilaraemia reduced by 88%-92%. However, when drug pressure was removed in the third and final year of the study, transmission was resumed in the absence of vector control whereas no infective female mosquitoes were detected in the villages with vector control. Vector control, though obviously not cost-effective in the short term, could play an important role in an integrated programme, by preventing re-establishment of transmission after chemotherapy is completed.

Adolescent↗
PubMed2000

Lung function in mitral stenosis.

OBJECTIVES: The aim of this study was to look to for a relationship between pulmonary artery pressure (PAP), left atrial pressure (LAP), mitral valve area (MVA) and transmitral gradient (Gr) on the one hand and the spirometric data on the other, in cases of mitral stenosis. METHODS: The spirometry values measured were forced vital capacity (FVC), forced expiratory volume in one second and as percent of FVC (FEV1, FEV1/FVC%), forced expiratory flow between 25% to 75% of FVC (FEF 25-75%), at 50% of FVC (FEF 50%) 75% of FVC (FEF 75%) and peak expiratory flow rate (PEFR). The PAP, LAP, MVA and Gr were measured at echocardiography and cardiac catheterisation. RESULTS: Analysis of results was done of 60 patients in four groups divided on basis of mean PAP: Group 1 with least and group 4 with highest mean PAP. FVC values were reduced in direct proportion to PAP, LAP, MVA and Gr in three out of four groups. FEV1% as a percent of predicted value showed uniform reduction in all the groups, PEFR was moderately affected in group 1 and most severely in group 4. Values of FEV1/FVC% were within normal range in all the groups. FEF 25-75%, and FEF 50% showed serial reduction in values in keeping with the elevation of the PAP. FEF 75% was also moderately affected in group 1 and most severely in group 4. CONCLUSION: We found that a moderate restrictive defect and a small airway defect which is found in cases of mitral stenosis, directly correlates to the PAP, LAP, MVA and Gr. There was no significant involvement of the larger airways.

Adolescent↗
PubMed1998

Larval ecology and mosquito fauna of upper Brahmaputra valley, northeast India.

Ninety-one mosquito species in 15 genera were collected from 22 habitat types of Upper Brahmaputra valley in Assam and bordering areas of Arunachal Pradesh. Nineteen species have been recorded for the first time in Assam including seven first records from the northeast region and three first country records. Jaccard's coefficient was used to quantify the similarity between 13 different geographical localities surveyed on the basis of their mosquito fauna. Group average sorting (UPGMA) cluster analysis was used to find out relationship between Jonai, Dhemaji, Dibrugarh, Tinsukia and north Lakhimpur (study zones) on the basis of their mosquito community. Immatures of three malaria vectors incriminated from the northeast India, viz. Anopheles dirus, An. minimus and An. philippinensis were collected exclusively from forest areas. Fourteen potential vectors of Japanese encephalitis incriminated from elsewhere in India were collected during the study.

Animals↗
PubMed1992

Detection of haemagglutination inhibition antibodies against Newcastle disease virus in unvaccinated indigenous chickens in Maiduguri, Borno State, Nigeria.

An examination of 200 serum samples from unvaccinated indigenous (local) chickens in Maiduguri, Borno State (Nigeria) using the haemagglutination inhibition (HI) test showed 73 sera to be positive and 127 to be negative for antibodies against Newcastle disease virus. The highest antibody titre observed was 1:128. The prevalence rate was higher (46.9%) in adult chickens than in young chickens of less than 12 weeks (23%). Presence of HI antibodies in unvaccinated indigenous chickens indicates that these birds had contracted infection and recovered thereafter.

Age Factors↗
PubMed1991

Excessive polycythaemia of high altitude. Pulmonary function studies including carbon monoxide diffusion capacity.

Pulmonary function studies were done in 21 soldiers (low landers) posted at high altitude (average height 4773 metres) for prolonged periods (average 77.09 months), who had developed excessive polycythaemia, mean haemoglobin concentration being 23.06 g/dl. Studies revealed significant reduction in diffusion capacity of lungs which gradually returned to normal on sojourn at low altitudes for 70 days. Both the degree of polycythaemia and reduction in lung diffusion capacity were much more pronounced in smokers than in non-smokers. Vital capacity did not show any difference in these subjects while forced expiratory volume in 1 sec and ratio of forced expiratory volume to vital capacity (FEV1/VC) revealed only obstructive features in smokers.

Adaptation, Physiological↗
PubMed1990

Pulmonary bullous disease in Marfan syndrome.

Two young adults with marfanoid features who had pulmonary bullous disease are presented. One a young soldier, presented with increasing dyspnoea and an enlarging large pulmonary bulla on the right side. The bulla was under tension and was operated on. The other case was a young housewife who also presented with dyspnoea, and was found to have a cardiac murmur and multiple ectopic beats on initial examination. X-Ray chest revealed bilateral pulmonary bullous emphysema. Both the subjects had many features which are accepted as forme fruste of the Marfan syndrome.

Adult↗
PubMed1990

Space-spraying with malathion as a supplementary measure for operational malaria control.

Entomological studies showed that due to outdoor resting by the vector Anopheles culicifacies as well as poor spray coverage, indoor residual spraying with malathion was ineffective in malarious villages of the Thenpennai riverine tract in Tamil Nadu. Over a 4 yr period during which residual spraying was supplemented with ground applications of malathion space spraying, the slide positivity among patients with fever fell from 21.04 to 1.1 per cent. In mass blood surveys 0.7 per cent persons surveyed at the beginning of the study were positive for the malarial parasite, but no positives were detected in the last survey, in 1984. There was a rising trend in malaria incidence in riverine villages outside the programme.

Animals↗
PubMed1989

Bilateral recurrent haemorrhagic pleural effusion in asymptomatic chronic pancreatitis.

In a case of bilateral recurrent haemorrhagic pleural effusion due to asymptomatic pancreatitis the diagnosis was suggested by the presence of amylase in the pleural fluid when other possible causes had been excluded. Abdominal computed tomography and laparotomy confirmed the diagnosis. No communications could be seen between the peritoneal and pleural space at laparotomy.

Adult↗
PubMed1989

Enlarging pulmonary histoplasmoma associated with pulmonary tuberculosis.

Histoplasmosis is not a frequently reported infection from India. Similarity of its clinical and radiological features with pulmonary tuberculosis, may cause a difficult diagnostic dilemma when the two occur together. We report a case who initially presented with cavitary lesions over right lung responding well to anti tuberculosis chemotherapy but subsequently a small opacity present over the left upper zone showed a relentless increase till it attained a massive size few years later. Operative removal and histopathological examination of the mass confirmed it to be histoplasmoma. She became sputum AFB smear positive and culture negative for a short while during this period and this is explained on the basis of previous reports.

Adult↗
PubMed1989

Significance of transplant perfusion index in the diagnosis of acute rejection in live related renal allograft recipients.

The study was undertaken to assess the usefulness of transplant perfusion index (TPI) in the differential diagnosis of renal allograft dysfunction with special reference to acute rejection. It was observed that the TPI has a sensitivity of 100 per cent and specificity of 98.1 per cent in the diagnosis of acute rejection. It was also observed that the serial values of TPI provided valuable clues and guide in the management of transplant dysfunction and helped in the immediate and long term follow-up of patients with renal allografts.

Adult↗
PubMed1989

Malignant mesothelioma in the young (with prosthetic aortic valve an unusual association).

A case of malignant mesothelioma (MM) in a 15 year old boy is reported. He had a prosthetic aortic valve implanted in 1980 at our centre for rheumatic aortic regurgitation. Fever, weight loss and chest pain as initial symptoms suggested possibility of prosthetic valve endocarditis. Dysphagia as another initial symptom was interesting and caused further diagnostic dilemma. Role of Computerised Tomography (CT) scan in diagnosis of MM is highlighted.

Adolescent↗