Outbreak prone communicable diseases of public health importance in the northern districts of West Bengal - Current status & the way forward.

India is perilously poised on the threshold of an explosion of infectious diseases, some of which have witnessed re-emergence while others await apposite opportunity to do so. The State of West Bengal is uniquely positioned with its innate geographical vulnerabilities that favour outbreaks of a host of infectious diseases. The northern districts of this State are well known endemic areas for many outbreak prone communicable diseases like malaria, Japanese encephalitis, scrub typhus, dengue and kala-azar. An outbreak of Nipah virus in the recent past is a pointer towards the emerging and re-emerging threat in these regions and warrants urgent prioritization for surveillance and monitoring of these diseases. Identification of risk factors, challenges in delivery of primary healthcare, implementation of intervention strategies along with strengthening of healthcare setup are also the need of the hour. Multisectoral initiatives with emphasis on understanding the complex and rapidly evolving human-animal-vector dynamics as envisaged under the 'One Health' concept are indubitably important pillars in the effective management of these emerging public health challenges.

Entomological investigations into an epidemic of Japanese encephalitis (JE) in northern districts of West Bengal, India (2011-2012).

BACKGROUND & OBJECTIVES: Japanese encephalitis (JE) is one of the most important arboviral diseases of human beings with outbreaks in many parts of Southeast Asia including India. We present the entomological findings of an outbreak occurred in northern part of West Bengal during 2011-2012 with special emphasis on the role of JE vectors in different seasons. METHODS: Adult mosquito collections were made with the help of mouth aspirators, aided by flash lights during day time resting inside human and animal habitations as indoor, and resting outside field grasses, bushes, underneath of culverts and bridges as outdoor, and in and around the pig enclosures and cattle sheds during dusk period in JE affected villages from Cooch Behar, Dakshin Dinajpur, Darjeeling and Jalpaiguri districts in North West Bengal. In all study villages, a long handled with enamel bowl dipper was used to obtain immature stages of mosquitoes from various breeding habitats. RESULTS: A total of 19 different types of mosquito breeding habitats were examined for vectors of JE. From these habitats, 23.7 per cent were positive for breeding during the study period. Overall, nine different species were recorded through emergence, but none was positive for JE virus when subjected for detection of virus. Adult mosquitoes of more than 50 per cent of the potential JE vector species obtained through dusk and the rest through indoor and outdoor collections in all seasons. Altogether, 27 different species were recorded. Most of these were JE vectors. INTERPRETATION & CONCLUSIONS: Our results showed that in addition to Cx. vishnui subgroup, detection of JE virus antigen in Cx. quinquefasciatus indicated the possible maintenance of JE virus in nature through poor vector mosquitoes throughout the year. Since, all potential vector species reported elsewhere in India were also found in this region and fluctuated in density in different seasons, a proper integrated vector control programme needs to be implemented to control JE transmission.

Goiter prevalence, urinary iodine, and salt iodization level in sub-Himalayan Darjeeling district of West Bengal, India.

National iodine deficiency disorders control program needs to be continuously monitored. Hence, a cross-sectional study was conducted during the period from April-May 2011 to assess the prevalence of goiter, status of urinary iodine excretion (UIE) level and to estimate iodine content of salts at the household level in Darjeeling district, West Bengal. Study subjects were 2400 school children, aged 8-10 years selected through "30 cluster" sampling methodology. Goiter was assessed by standard palpation technique, UIE was estimated by wet digestion method and salt samples were tested by spot iodine testing kit. Overall goiter prevalence rate was 8.7% (95% confidence intervals = 7.6-9.8) and goiter prevalence was significantly different with respect to gender. Median UIE level was 15.6 mcg/dL (normal range: 10-20 mcg/dL). About 92.6% of the salt samples tested had adequate iodine content of ≥15 ppm. Findings of the present study indicate that the district is in a transition phase from iodine-deficiency to iodine sufficiency.