Studies on community knowledge and behavior following a dengue epidemic in Chennai city, Tamil Nadu, India

In 2001, a major dengue outbreak was recorded in Chennai city, with 737 cases (90%) out of a total of 861 cases recorded from Tamil Nadu state. A KAP survey was carried out to assess the community knowledge, attitude and practice on dengue fever (DF), following the major dengue outbreak in 2001. A pre- tested, structured questionnaire was used for data collection. The multistage cluster sampling method was employed and 640 households (HHs) were surveyed. Among the total HHs surveyed, 34.5% of HHs were aware of dengue and only 3.3% of HHs knew that virus is the causative agent for DF. Majority of the HHs (86.5%) practiced water storage and only 3% of them stored water more than 5 days. No control measures were followed to avoid mosquito breeding in the water holding containers by majority of HHs (65%). Sixty percent of HHs did not know the biting behaviour of dengue vector mosquitoes. The survey results indicate that the community knowledge was very poor on dengue, its transmission, vector breeding sources, biting behavior and preventive measures. The lack of basic knowledge of the community on dengue epidemiology and vector bionomics would be also a major cause of increasing trend of dengue in this highly populated urban environment. There is an inevitable need to organize health education programmes about dengue disease to increase community knowledge and also to sensitize the community to participate in integrated vector control programme to resolve the dengue problem.

A study on chikungunya outbreak during 2007 in Kerala, south India.

Background & objectives: The first chikungunya outbreak occurred in Kerala during 2006 affecting 14 districts, followed by another during May 2007 affecting almost whole of the State. Four of the worst affected districts viz, Pathanamthitta, Idukki, Kottayam and Thrissur were surveyed during 2007 to understand the magnitude of the problem of chikungunya fever, particularly clinical signs and symptoms. Methods: A total of 1265 persons from 310 houses were surveyed door-to-door in 20 different localities representing four affected districts. The history and examination findings from 354 clinically diagnosed chikungunya cases were recorded. The symptoms recorded were fever, headache, myalgia, arthralgia, itch/rash, oedema, eye congestion, eye pain, oral ulcers, distaste, nausea, vomiting and haemorrhage. Results: The major symptoms were fever (100%), headache (97.5%), arthralgia (99.4%) and myalgia (99.4%). A significant difference was observed in oedema, distaste, nausea and headache among different age groups and these symptoms were reported to be lower (12.2-89.8%) in younger age group than in older age group (90.4-100%). No genderwise difference was observed for any of the symptoms. In clinically diagnosed chikungunya cases higher age group (>35 years) found with higher rate of severity with symptoms of oedema, distaste, nausea and headache when compared with lower age group (1-35 yr). Interpretation & conclusions: Chikungunya invaded Kerala State for the first time in 2006 and continues to be a major vector borne disease in the State. The clinical symptoms in affected cases highlighted high fever, sever myalgia and prolonged arthralgia, with occasional history of skin itch/rash (petechiae).

Natural vertical transmission of dengue viruses by Aedes aegypti in Chennai, Tamil Nadu, India.

BACKGROUND & OBJECTIVE: Dengue viruses are spread and maintained in an Aedes aegypti-human- Ae. aegypti cycle in urban areas of the tropics. Dengue viruses are also maintained in nature by vertical transmission by Ae. aegypti. A study was undertaken in Chennai, a known endemic city in south India, to comprehend the natural vertical transmission dynamics in Ae. aegypti and to assess its epidemiological importance. METHODS: Ae. aegypti males collected in resting and landing collections were tested for dengue virus infection by antigen-capture enzyme-linked immunosorbent assay (ELISA) and further examined by insect bioassay, Toxorhynchites splendens inoculation-indirect immunofluorescence technique (Toxo-IFA) using serotype-specific monoclonal antibodies (Mabs), if found positive by ELISA. RESULTS: Of the 509 pools of Ae. aegypti males (n=5408) screened, 15 pools, collected in April, June- July, November-December in 2003 and March, May in 2004, were found positive for dengue virus infection and the minimum infection rate (MIR) among adult males was high in June 2003 (28.0/ 1000). Three positive pools could be serotyped as dengue-2 (2 pools) and dengue-3 (1 pool). INTERPRETATION & CONCLUSION: Dengue virus isolations from wild caught males of Ae. aegypti indicate the occurrence of transovarial transmission. Vertical transmission was mainly observed in summer months when dengue infections in humans were low suggesting that dengue viruses adopt a novel strategy of surviving adverse climatic conditions.

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.

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.

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.

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.

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.

Necrobiotic pulmonary nodule leading to pyopneumothorax in a case of rheumatoid arthritis--a rare clinical presentation.

A 49-year-old male patient, an active case of sero positive rheumatoid arthritis involving multiple joints with bilateral necrobiotic pulmonary nodules is presented. Initial symptoms were of progressively increasing dyspnoea. The nodule in the right lung subsequently cavitated leading to pyopneumothorax. The diagnosis of rheumatoid lung was confirmed by post-mortem.

Osler-Rendu-Weber disease presenting as recurrent haemoptysis.

A young adult male with a short history of recurrent haemoptysis due to vascular malformation of right lung is presented. Lesion was not visible in the chest radiograph, nor on bronchography. CT-scan of thorax, however, showed a bunch of circinate opacities in the upper lobe of the right lung. Histopathological examination of the resected lung tissue confirmed the diagnosis.

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.

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.