More than 400 people in northern India have died in the past month from encephalitis, a rare condition that causes inflammation of the brain, government officials said on Wednesday.
Encephalitis is most often caused by a viral infection from eating or drinking contaminated food or water, from mosquito or other insect bites, or through breathing in respiratory droplets from an infected person.
Around 347 people have died in Uttar Pradesh, while 54 children have died in the neighbouring state of Bihar. Over two thousand cases have been reported in the last three months.
"Acute Encephalitis Syndrome has two types of infections - Japanese Encephalitis, which occurs due to mosquitoes and Entro-viral Encephalitis, which is caused due to unsafe drinking water," said Dinesh Kumar Srivastava from the Community Medicine Department in Uttar Pradesh's Gorakhpur district, where patients are receiving treatment.
Officials said the main areas where the outbreak of the virus has been noticed have been poor, flood-hit areas of the region, where this year's monsoons have left pools of stagnant water that have allowed mosquitoes to breed and infect villagers.
The floods have also led to the contamination of clean water sources such as wells, leaving many people with no option but to use the same dirty water for both drinking and sanitation.
According to the World Health Organisation, viral encephalitis causes high fever, headache, stiff neck and back, vomiting, confusion and, in severe cases, seizures, paralysis and coma. Infants and elderly people are particularly at risk of severe illness.
The infection spreads every year in impoverished parts of Uttar Pradesh during the monsoon season, resulting in hundreds of deaths.
Officials say the government has earmarked 22 million rupees ($450,000) to tackle problems like the unavailability of clean drinking water, lack of sanitation and water-logging, to prevent the virus from spreading.
But local aid workers say efforts need to be stepped up.
"The infection started in the early 1970s and since then it has become an annual feature. The government is adopting short term measures to deal with the infection instead of making any long term plan to get rid of the virus,” said Sanjay Kumar Srivastava from Action for Peace, Prosperity and Liberty (APPL), a charity doing research on the disease.
"Besides, no preventive measures are taken to stop the outbreak," he added, suggesting that vaccinations be more readily available to adults as well as to children.