As many as 35 persons tested positive for dengue fever in Nagpur city in October.
Dr Milind Ganvir, Deputy Director (Health), said the Nagpur Municipal Corporation had sent blood samples of 213 patients to NIV (National Institute of Virology), Pune, which confirmed 35 people as dengue-infected.
Health department had started door-to-door survey and so far come across 11,480 houses where surroundings were favourable for breeding of mosquitoes, he said.