PATNA, India (AP) — Indian authorities said Wednesday that 114 children have died in an encephalitis outbreak this month in eastern Bihar, one of the country’s poorest states.

The outbreak has been exacerbated by a heatwave, with temperatures in Patna, Bihar’s capital, reaching a high of 45.8 Celsius (114.5 Fahrenheit).

There have been more than 500 cases of encephalitis registered since the outbreak began June 1, according to a government health bulletin released Wednesday.

Some 170 children were being treated at hospitals in Bihar’s Muzaffarpur district, 80 kilometers (50 miles) north of Patna, including 11 in critical condition.

Infected patients were sharing beds in crowded hospital wards with too few doctors, while families who could afford it transferred their children to private hospitals in Patna and other larger cities.

Young children are particularly vulnerable to the illness, which can cause swelling of the brain, fever and vomiting.

Thousands of Indians suffer from encephalitis, malaria, typhoid and other mosquito-borne diseases each year during the summer monsoon season.

Medical experts say India’s central and state governments remain unprepared for what is now an annual cycle of disease and death.