NEW DELHI, July 25 (Thomson Reuters Foundation) - Almost 570 people in India have died after contracting encephalitis, commonly known as "brain fever", health authorities said on Friday, warning the death toll may rise further.
Outbreaks of both Acute Encephalitis Syndrome and Japanese Encephalitis are common during India’s monsoon season and claim hundreds of lives each year.
But this year, major outbreaks - usually most concentrated in the northern states of Uttar Pradesh and Bihar - have spread to other regions such as West Bengal and Assam - killing 568 people.
In West Bengal, where at least 111 people have died from both strains, a senior health official said authorities were taking emergency steps to contain the outbreak.
"We have sounded an alert in seven districts and cancelled the leave of all health department officials," West Bengal's Health Services Director B.R. Satpathy told Thomson Reuters Foundation.
Encephalitis is an inflammation of the brain, caused by any one of a number of viruses, says the World Health Organisation. Symptoms include high fever, vomiting and, in severe cases, seizures, paralysis and coma. Infants and elderly people are particularly vulnerable.
It is most often caused from eating or drinking contaminated food or water, from mosquito or other insect bites, or through breathing in respiratory droplets from an infected person.
The virus most commonly occurs in poor, flood-hit areas, where monsoons have left pools of stagnant water, allowing mosquitoes to breed and infect villagers.
Floods also lead to the contamination of water sources such as wells, leaving many people with no option but to use the same dirty water for both drinking and washing.
Health Minister Harsh Vardhan said last month he was extremely distressed by the "runaway conquest of encephalitis" and ordered all children in vulnerable states to be vaccinated against the virus and for a proportion of hospital beds to be dedicated to encephalitis patients.
In 2012, the Indian government launched a national programme to prevent and control the virus.
This included more widespread vaccination programmes, strengthening surveillance and improving access to safe drinking water and proper sanitation facilities.
There were 1,273 deaths in India due to encephalitis in 2013 compared to 440 deaths from malaria and 193 from dengue fever, government statistics show.
(Editing by Ros Russell; Additional reporting by Sujoy Dhar in KOLKATA)