Vw Tilak

Emergence of Schoengastiella ligula as the Vector of Scrub Typhus Outbreak in Darjeeling: Has Leptotrombidium deliense Been Replaced?

BACKGROUND Following a suspected outbreak of scrub typhus in Kurseong, Darjeeling, the Armed Forces Medical College, Pune was requested by the National Institute of Epidemiology and the State authorities to undertake investigation of the ongoing scrub typhus outbreak and suggest containment measures. MATERIALS AND METHODS The epidemic team undertook clinical, entomological and serological studies to understand the local disease pattern and delineate high risk areas, host diversity by rodent trapping using Sherman traps, mite fauna diversity, abundance and vector species identification by phase contrast microscopy for preparation of electronic database and rodent and human serological studies by Weil Felix and PCR. RESULTS The results indicate no association of scrub typhus with age and sex (P=0.37 and 0.74 respectively). The maximum cases occurred amongst the tea garden workers (73%) in the age group of 25-44 years. The predominant clinical presentation was fever (100%) with headache (75%), lymphadenopathy (45%) and presence of eschar (76.7%). The dominant host species (50% of trapped rodents) was shrew Suncus murinus, the index animal for scrub typhus, which contributed maximally to the vector abundance (52.96%) with a chigger index of 61.56. The trombiculid mite Schoengastiella ligula was the vector species much against the expected mite vector Leptotrombidium deliense, in the area. The study found the presence and abundance of vector species which corroborated well with the occurrence of cases in the various localities within the subdivisions. CONCLUSION The study thus establishes Schoengastiella ligula as the vector of scrub typhus outbreak in Kurseong, Darjeeling. Preventive and containment measures with emphasis on reduction of man - vector contact were suggested to the state authorities to contain the outbreak.

AN INTRODUCTION TO ESSENTIALS OF BIO-MEDICAL WASTE MANAGEMENT

The issue of biomedical waste management has assumed great significance in recent times particularly in view of the rapid upsurge of HIV infection. Government of India has made proper handling and disposal of this category of waste a statutory requirement with the publication of gazette notification no 460 dated 27 July 1998. The provisions are equally applicable to our service hospitals and hence there is a need for all the service medical, dental, nursing officers, other paramedical staff and safaiwalas to be well aware of the basic principles of handling, treatment and disposal of biomedical waste. The present article deals with such basic issues as definition, categories and principles of handling and disposal of biomedical waste.

A MATHEMATICAL MODEL FOR PREDICTING THE PERSISTENCE AND EFFICACY OF BACILLUS THURINGIENSIS VAR ISRAELENSIS IN RELATION TO WATER POLLUTION

In a simulated field trial, the bead formulation of Bacillus thuringiensis var israelensis (Bti) was found to be more persistent in moderately polluted as compared to highly polluted water. A mathematical model was built up to study the influence of time (independent variable) on larval reduction (dependent variable) in relation to degree of water pollution. Two predictive models for different grades of water pollution were developed, which estimated that the larval mortality in moderately polluted water was likely to decline by 3.79 as compared to 5.02 on an average, in highly polluted water with each passing day.

HEALTH AWARENESS VERSUS ECONOMIC AFFLUENCE AS DETERMINANTS OF HEALTH STATUS : A COMMUNITY BASED EPIDEMIOLOGICAL ANALYSIS

A community-based cross-sectional analytic epidemiological study was undertaken to compare the health status of school children from two villages and to see the association of the school childrens health status with the level of health awareness among parents and teachers. The two villages had only one major difference, i.e., one had an agriculture-based economy and was more affluent than the other village. The study, however, revealed that the overall morbidity and nutritional deficiencies were significantly less (p < 0.01) and immunization status significantly better (p < 0.01) among school children of the less affluent village, possibly because level of health awareness was significantly higher among parents and teachers of this village as compared to the more affluent one (p < 0.01). The importance of health education has been reinforced by this study.

APPLICATION OF STRATIFIED ANALYSIS IN EPIDEMIC INVESTIGATIONS : ANALYSIS OF AN OUTBREAK OF FOOD POISONING

The present study demonstrates the use of stratified analysis when high (or low) risk is observed for two or more food items during the investigation of food poisoning, rather than simply implicating the item showing the highest risk. In this study an outbreak of food poisoning, which exhibited a clinico-epidemiological profile of Clostridium perfringens as the possible agent, was investigated using a case-control typology. Evaluation of food histories showed a high and significant odds ratio (OR) for a mutton dish (OR = 6.45, p < 0.001) and peas dish (OR = 5.6, p < 0.001), while a legume dish showed a protective effect (OR = 0.13, p < 0.001) which proved erroneous. Stratified analysis using Mantel-Haenszel procedure indicated that the risk due to mutton persisted even after adjusting for consumption of peas (adjusted OR = 4.22) or legume dish (adjusted OR = 4.25). The use of stratified analysis in investigating epidemics has been recommended.

Surveillance of Scrub Typhus in the fringe areas around Pune : Potential for Transmission does exist

A field based epidemiological study was undertaken to assess the potential of transmission of scrub typhus in the sylvatic and transitional (fringe) areas at ten different locations around Pune. Parameters studied included rodent trapping and identification, entomological parameters, immunological studies on rodent sera, and rodent organ impression smears. The study revealed that Rattus r rufescence, Rattus meltada, Suncus murinus and Rattus blanfordi were the predominant sylvatic rodent species. All the species showed mild to moderate infestation with trombiculid mite larvae, with Rr rufescence and S murinus showing even higher levels of infestation. Pooled rodent sera showed mild rise of OX2 in 13.9%, OX19 in 5.6% and OXK in 9.8% of the pooled sera. The rise in titres was appreciable among rodents from Lonavala, Khadakvasla, Panchet, Singhgadh and Kondhwa areas. Based on the findings of the study, certain recommendations on prevention, surveillance and epidemic investigations of scrub typhus in the Armed Forces have been submitted.

Cohort Study on the Recurrence Rate of High Altitude Pulmonary Oedema

Keeping in view the importance of High Altitude Pulmonary Oedema (HAPO) as well as the absence of published evidence as regards recurrence rate of this disease, a cohort study was undertaken, based on data available with the Central Diseases Registry. The inception cohort consisted of all cases of HAPO occurring over a one year period, This cohort was followed up for another 12 months, to observe any recurrence. The study revealed that the recurrence rate of HAPO in terms of Incidence density was 1.83 per 1000 person-months of those who had an initial episode (95% confidence limit 0.53 to 3.13 per 1000 person-months). The cumulative incidence was 32.9 per 1000, over an average follow up of 18 months (95% confidence limit 4.55 to 61.25 per 1000). The time gap between the initial episode and recurrence was 115 to 208 days. All recurrent cases had their initial as well as recurrent episode at the first stage of high altitude (9000 to 12000 feet), with the onset being within 48 hours of entry into high altitude. Based on the findings, some recommendations for prevention of recurrence of HAPO have been submitted.

A PSYCHODEMOGRAPHIC STUDY OF THE PATIENTS OF A DEADDICTION CENTRE IN PUNE

One hundred and twelve patients who reported to a de-addiction centre were investigated with regard to their psychodemographic profile, 66.07% of them turned out to be exclusive alcohol dependent. Six (5.35%) of them turned out be exclusively dependent on brown sugar. About 28.57% of patients were dependent on more than one drug in various combinations. The mean age of onset of drug use was 26.8 years and mean age of reporting for treatment was 36.6 years. 66% of the drug dependents started first with alcohol as the initial drug followed by 26.78% of drug dependents with nicotine in the form of smoking bidi/cigarette or taking gutka. Other than the withdrawal syndrome the other associated psychiatric disorders were anxiety, depression, suicidal attempts, sleeplessness, drug induced psychosis and antisocial personality disorder.

CROSS SECTIONAL ANALYTIC STUDY OF AWARENESS REGARDING FACTORS RELATED TO CHILD SURVIVAL AMONG MARRIED WOMEN IN A SEMI-URBAN COMMUNITY

A cross sectional analytic study was undertaken on 480 married women living in a semi-urban locality in Pune, with the objective of assessing their awareness regarding factors related to child survival. It was observed that 62.1 per cent of the ladies had adequate knowledge about immunisation. A highly significant trend was evident as regards knowledge about immunisation and formal education and socio-economic status (p<0.01). 93 per cent ladies initiated breast feeding within 24 hours of birth of the new born. Significantly larger proportion of ladies from lower education favoured prolonged breast feeding (p<0.001) and favoured late introduction of top milk (p<0.001). In general, the awareness about growth chart was very poor with only 3.5 per cent ladies having adequate knowledge. Larger family size was significantly associated with declining probability of use of oral rehydration solution (ORS). Certain recommendations for improving the awareness regarding child survival have been submitted accordingly.

APPLICATION OF HAZARD ANALYSIS CRITICAL CONTROL POINT SYSTEM : ANALYSIS OF A FOOD POISONING OUTBREAK

The World Health Organization as well as several experts have recently recommended the use of hazard analysis critical control point system for prevention of food-borne illnesses. The present study proceeded to identify the hazardous operations and their critical control points by investigating, through a case-control design, an outbreak of food poisoning. The predominant presenting symptoms were watery diarrhoea and abdominal cramps. The cumulative incidence during this episode was 28.6 per cent, with a median incubation of 13 hours. Evaluation of food histories indicated a very high and significant odds ratio for mutton dish (OR = 6.45; p < 0.001), which persisted even after adjusting for the consumption of other food items through stratified analysis using the Mantel-Haenszel procedure. Environmental assessment revealed a strong possibility of contamination of raw mutton at the source with animal excreta and prolonged storage at room temperature of cooked mutton dish. Based on these findings, hazardous operations were identified and critical control points and monitoring criteria for prevention of food poisoning have been suggested.