Dengue, chikungunya and the missing entity - Zika fever: A new emerging threat.

Zika virus (ZIKV), a relative newcomer from the flavivirus group that includes dengue, Japanese encepahalitis and yellow fever, is one of the emerging pathogens that is fast transcending geographical boundaries. It is a vector-borne disease transmitted by the same Aedes aegypti and Aedes albopictus, which cause dengue and chikungunya. In addition to the vector-mediated transmission of Zika fever, probable human-to-human transmission through exchange of body fluids, including sexual and perinatal transmission and through blood transfusion, makes containment of this new entity more challenging. Moreover, a high index of suspicion by an astute physician is necessary for diagnosis of Zika fever in view of the similarity of symptoms with dengue and chikungunya, especially in areas, where these two diseases are already endemic. Zika, till recently, has had minimal impact, but its true potential is unfolding with increasing detection of congenital malformities, Guillain-Barré syndrome and other neurological and autoimmune syndromes in patients with recent history of ZIKV infection, or when mothers get infected with Zika during first or second trimester of pregnancy. The association, however, needs to be established, nonetheless it is important that we keep a close vigil on this emerging vector borne disease - the 'ZIKA' fever.

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.

Insecticide treated bednet strategy in rural settings: can we exploit women's decision making power?

Use of insecticide treated bednets in prevention of malaria is a widely propagated global strategy, however, its use has been reported to be influenced and limited by many variables especially gender bias. A cross sectional field epidemiological study was conducted in a rural setting with two outcome variables, 'Bednet use'(primary outcome variable) and 'Women's Decision Making Power' which were studied in reference to various predictor variables. Analysis reveals a significant effect on the primary outcome variable 'Bednet use' of the predictor variables- age, occupation, bednet purchase decision, women's decision making power, husband's education and knowledge about malaria and its prevention. The study recommends IEC on treated bednets to be disseminated through TV targeting the elderly women who have better decision making power and mobilizing younger women who were found to prefer bednets for prevention of mosquito bites for optimizing the use of treated bednets in similar settings.

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.

Efficacy of Fipronil and Propoxur in the control of German cockroaches (Dictyoptera: Blatellidae).

A field trial for comparative evaluation of chemicals Fipronil gel, Propoxur spray and bait was carried out. The results in the Fipronil treated area indicate a reduction of 89%, 100% and 98% in cockroach infestation by days 7, 30 and 60, whereas the reduction in Propoxur spray treated area during the same period was 88%, 91% and 87% respectively. Propoxur bait was not found to be effective in reducing the cockroach infestation; rather a build up of the cockroach infestation was noticed in the treated site. The study reports the efficacy of Fipronil gel treatment over conventional insecticidal formulations in the control of cockroach infestation in cookhouses of urban households.

Laboratory evaluation of repellents against Leptotrombidium deliense, vector of scrub typhus.

BACKGROUND & OBJECTIVES: Scrub typhus, a rickettsial disease transmitted by larvae of Leptotrombidium deliense, is of special importance to the Armed Forces personnel, due to the heightened risk to this disease during movement in mite endemic areas during exercise/war. The disease is best prevented by the use of personal protective measures including repellents. Studies were undertaken to determine the relative efficacy of repellents: diethyl toulamide (DEET), dibutyl phthalate (DBP) with an indigenously developed repellent diethyl phenyl acetamide (DEPA) against the larval trombiculid mite. METHODS: The repellents were tested for persistence on impregnated cloth prior to washing, post washing and ironing by means of a specially fabricated testing kit. Acaricidal efficacy estimation was performed on the treated fabrics and topical application efficacy of repellents on mice was evaluated by a novel animal testing model. RESULTS: DEET and DEPA were found to provide maximum protection (repellence and acaricidal efficacy), could withstand two launderings of the impregnated uniform and also had superior efficacy on topical application (8 h). Ironing was found to significantly reduce the repellence of DEET and DBP. INTERPRETATION & CONCLUSION: The findings of this study point towards the superiority of DEPA and DEET for impregnation of the uniform cloth as well as for topical application for the prevention of scrub typhus amongst the troops.

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.

Differential efficacy evaluation of formulations of Bacillus thuringiensis Var israelensis against mosquitoes: a laboratory investigation.

The efficacy evaluation of three formulations; wettable powder (W.P.) floating pellet and beads of Bacillus thuringiensis Var israelensis (Bti), revealed a greater susceptibility of the early larval instars of mosquitoes to Bti, sensitivity of anophelines to floating pellet, culicines to bead and equal efficacy and faster kill of W.P. to all the mosquitoes tested. A greater persistence of the slow release formulations, floating pellet and beads for 49 and 28 days against anophelines and culicines respectively was observed in contrast to a maximum persistence for 21 days in case of W.P. formulation.

EPIDEMIOLOGICAL STUDY OF ENTEROPATHOGENIC CARRIER STATE AMONG FOOD HANDLERS OF ARMED FORCES EATING ESTABLISHMENTS.

A cross-sectional epidemiological study was undertaken on a randomly selected sample of 308 food handlers working in different eating establishments of Indian Armed Forces in Pune. These included 101 Service personnel and 207 civilians. Stool samples were analysed for enteropathogens and epidemiological assessment of gastrointestinal disease occurrence in the military units of these food handlers was undertaken. The study revealed that 4 of the subjects were carriers of salmonella typhimurium, thus giving the prevalence as 1.3% (95% confidence interval 0.2% to 2.56%). No other enteropathogen except salmonella typhimurium was isolated. The positive carriers showed a typical "spatial - clustering" in that they were working in two geographically contiguous medical units.

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.

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.

EFFECTIVENESS OF A HEALTH EDUCATIONAL PACKAGE FOR AIDS PREVENTION AMONG ADOLESCENT SCHOOL CHILDREN.

A randomised, controlled, community based intervention trial was undertaken to assess the effectiveness of a Health Education Programme (HEP) for HIV infection and AIDS among school children at Pune. Sample size was calculated on the basis of conventional Type I and Type II errors. School children studying in classes 9th to 12th in six different schools (n=1102) formed the study material. Baseline assessment for knowledge for AIDS/HIV was undertaken and used for formulating the Health education Programme Package. Randomisation was done so as to allocate five schools into trial group (n=803) and one school into control group (n=299). Blinding was also ensured to reduce bias. The study revealed that the HEP was very effective in improving the knowledge, the difference being highly significant as compared to control group. The effect was specially well marked for girls in school level (OR=4.76) followed by boys intermediate level (OR=3.11); there was clear evidence of statistical effect modification as regards this 'sex and educational class' differential (Woolfs'chi square=11.82, p < 0.0001). The study also revealed that the maximum aceceptability of programme was among girls studying in girls school (Stratum OR =2.25) followed by boys in boys school (OR=1.50) compared to students in co-educational system (linear trend chi square=9.35, p < 0.01). Certain recommendations for health education for HIV/AIDS among school children have been submitted.

Evaluation of some risk factors for ischaemic heart disease under a matched pairs case-control design.

A pair-wise matched case-control study was carried out in 200 male patients of ischaemic heart disease (IHD). The cases were matched with an equal number of controls in respect of the variables viz., age and socio-economic status. The objective was to quantify the risk of developing IHD for some of the leading risk factors under the univariate and multivariate situations. The analysis revealed that of the factors (smoking, overweight, hypertension, diabetes, serum cholesterol and family history) considered, the smoking habit of the individual, presence of family history of the disease and overweight were the significant risk factors responsible for the development of the disease. The estimated odds ratios were found to be 3.29, 2.60 and 2.00 respectively.

Epidemiological study of an outbreak of cholera in Delhi cantonment.

An epidemiological study was undertaken to investigate an outbreak of cholera in Delhi Cantonment during May 1991. The study design was a hybrid design using a retrospective Case-Control method superimposed on a population based cross-sectional approach. A total of 9 cases of cholera, confirmed in the laboratory as Vibrio cholerae, 0-1, Eltor, Ogawa were identified using population based survey and compared with 33 controls from the same source population. The overall Incidence rate was 0.71% and showed a significant rising trend with age. There was no morality. Assessment of water supply, sanitary conditions of cook houses and disposal system of night soil could not provide any clue to the source of infection. Subsequently, all the food handlers were subjected to rectal swab examination. Two of them, working in the same messes from where cases had occurred, were found positive for Vibrio cholerae (0-1, Eltor, Ogawa). Immediate control measures by way of isolation and treatment of carriers promptly abated the outbreak. Role of carriers in outbreak of cholera has been highlighted.

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 children's 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 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.

COMPARATIVE EFFICACY OF d-PHENOTHRIN AND MALATHION IN THE CONTROL OF PEDICULOSIS.

A study was conducted in a semi-urban community of Pune for estimating the prevalence of pediculosis (head lice) and evaluating the relative efficacy of d-phenothrin and malathion. A total of 729 subjects from the community and 126 school children were included in the study. A prevalence of 69 per cent in the community and 54 per cent in school children was found, d-phenothrin had a better pediculicidal (84%) and ovicidal (62%) activity as compared to malathion (82% pediculicidal and 40% ovicidal activity).