Preventive measures for Japanese Encephalitis

The rising death toll due to Japanese Encephalitis (JE) in Assam is a worrying development. Cumulative cases in the current month have risen to 274 while the cumulative death of 44 people over the past 26 days is indicative of how the spread of the disease has become critical following the second wave of flood in the state. June, July and August are the months of high transmission of the viral disease, scaling up preventive measures and awareness campaigns for personal protection against mosquito bites is crucial to prevent infection and fatalities. Acute fever, severe headache, irritability, convulsion and loss of consciousness are symptoms of this vector-borne disease but difficulty in clinically differentiating it from another viral encephalitis often leads to delay in timely clinical management. Official data show that JE is endemic to 336 districts of 24 states and union territories and around 50-80% of the disease burden is contributed by five states - Assam, Bihar, Tamil Nadu, Uttar Pradesh, and West Bengal. Apart from high case fatality, disability in survivors continues to be an area of major concern for the government and health experts. According to the National Centre for Vector Borne Diseases Control, Directorate General of Health Services, Ministry of Health and Family Welfare, Culicine mosquitoes mainly Culex Vishnu group (Culex tritaeniorhynchus, Culex vishnui and Culex pseudovishnui) are the chief vectors of JE in different parts of India. It is transmitted by infective bites of female mosquitoes mainly belonging to Culex tritaeniorhynchus, Culex vishnui and Culex pseudovishnui group. However, some other mosquito species also play a role in transmission under specific conditions. Amongst patients who survive, some lead to full recovery through steady improvement and some suffer with stabilization of neurological deficit. The convalescent phase is prolonged and varies from a few weeks to several months, it cautions. The JE virus is primarily spread through a mosquito bite from water birds like cattle egrets, and pond herons to pigs and cattle while the human is the "dead end host" which means it is not transmitted from human to human. Ensuring that pig farms are located at least 100 metres away from the human settlement is an important preventive measure. Health advisory issued by the Assam government for prevention of the disease includes avoiding waterlogged areas, using mosquito nets, using insecticide, and keeping surroundings and drains clean. Health authorities, as well as district and local administrations, are concerned about taking these preventive measures like spraying larvicide in drains, taking steps to clear the clogged drains, draining stagnated water and ensuring every household has enough mosquito nets to protect every family member in flood-hit areas and all other areas can check the spread of the disease. Although the first case of JE was reported in India in 1955, the first major outbreak was reported in the Burdwan district in West Bengal in 1973 while in it was in 2005 a major outbreak of the disease in eastern Uttar Pradesh with more than 6,000 cases and 1,500 deaths led health intervention, including JE vaccination to the centre stage of vector disease control policy regime. Official data show that the JE vaccination campaign in children (1-15 years) has been completed in 297 districts till 2021. The Assam government launched a massive JE vaccination drive for the 15-65 years age group with a target of covering 40 lakh people. The pace of the vaccination drive will be critical to achieving the target, but the experience gained from huge success in the COVID-19 vaccination drive is expected to help the Health Department overcome the challenges. Cooperation from the targeted population and determination and proper planning by all districts concerned will be crucial to achieving the desired success. Three doses of the vaccine provide immunity lasting a few years. Two doses are administered within a gap of 7-14 days followed by the third dose any time after one month and before one year of the second dose and a booster is required after three years. Limitations in vaccine availability had been preventing JE vaccination on a mass scale and children in the 1-15 years age group are prioritized as they were found to be more vulnerable. While vaccination is a long-term strategy, immediate prevention measures like intensifying disease surveillance, and reaching out to the targeted population through traditional and social media to push the awareness drive on mosquito control and sleeping under bed net into a major social campaign can produce effective results. Even though the fatalities are not as high as in 2019, every single life matters and there can be no room for any complacency. The JE outbreak in the state claimed over 660 lives during the period from 2015 to 2021 and in 2019 alone altogether 161 people died of the disease against 135 deaths in 2015. Any laxity can prove to be catastrophic. Apart from measures initiated by the health authorities, awareness among people is crucial to prevent it from becoming a public health emergency.