Japanese encephalitis killed at least 21 people in northern India overnight Tuesday, bringing the death toll from the mosquito-borne disease to 670 since midsummer.
Most of dead in the outbreak in Uttar Pradesh - India's largest state and one of its poorest - were children under 15, state health officials said.
Sixty-seven new patients were admitted to state-run hospitals on Monday while another 21 died overnight.
More than 3,000 patients are being treated in government hospitals with symptoms of Japanese encephalitis, which causes high fever and vomiting and can sometimes lead to coma and death. It is spread by mosquitos that breed in water puddles left by annual monsoon rains that run from June through September, officials say.
At least 542 people have died in Gorakhpur.
According to federal health authorities more than 20 million children across 60 districts in northern India, where Japanese encephalitis is considered endemic, would be vaccinated against the disease, the AP reports.