Winter has brought no respite for eastern Uttar Pradesh residents from the killer Japanese encephalitis virus (JEV) and the acute encephalitis syndrome (AES) - which have already caused 623 deaths this year.
Every day, an average of a dozen children infected with JEV/AES are being admitted to Baba Raghav Das (BRD) Medical College in Gorakhpur. A total of 3,182 people so far have been infected.
Usually, JEV is active during summers and monsoon as the virus is mosquito-borne, and the most common cause of AES.
However, AES can also be caused by the water-borne entero-viruses, which enter through the digestive tract.
Scientists at National Institute of Virology (NIV) in Pune said heavy rainfall in eastern UP and neighbouring states due to cyclone Phailin that hit Odisha in October could account for entero-viruses causing AES.
"Heavy rainfall led to a rise in the groundwater table. Hence, the majority of AES patients might be infected with the water-borne viruses," said Milind Gore, a scientist at NIV.
Dr KP Kushwaha, principal of BRD Medical College, said the JEV was active as the minimum temperature was still 3 degrees above normal. "We hope the virus subsides by mid-December, when the minimum temperature falls," he said.
A health department official said, "We are redrawing the encephalitis control programme. Immunisation drive in affected districts will begin at the start of the new year."