Japanese encephalitis
The outbreak was originally mistaken for Japanese encephalitis, but physicians in the area noted that persons who had been vaccinated against Japanese encephalitis were not protected in the epidemic, and the number of cases among adults was unusual. Although these observations were recorded in the first month of the outbreak, the Ministry of Health failed to take them into account, and launched a nationwide campaign to educate people on the dangers of Japanese encephalitis and its vector, "Culex" mosquitoes.