Dengue risk remains closely tied to small pockets of stagnant water in and around homes, ICMR director-general Rajiv Bahl said during a visit to Calcutta, warning that even flower pots and discarded bottles can become breeding sites for the mosquito that transmits the disease.
Bahl, who is also secretary in the Department of Health Research, said dengue-causing mosquitoes often breed inside or close to houses. A flower pot containing water can support mosquito breeding, while eggs already present in the pot can hatch when water is added. A bottle left outside with a small quantity of water can also become a breeding ground, he said.
The warning comes as Bengal has reported 6,026 dengue cases till September 9, according to a state health department official cited in the report. The official said the number was lower than the figure recorded during the corresponding period last year. August and September are considered critical months for dengue transmission, experts said.
Bahl also urged people to protect themselves from mosquito bites during the day. The mosquito that transmits dengue is a day-biting mosquito, he said, advising the use of mosquito repellents and ointments throughout the day.
He distinguished dengue vector control from malaria control, saying the mosquitoes that transmit the two diseases have different breeding patterns. Malaria-causing mosquitoes generally breed outside homes and are easier for authorities to control, Bahl said. Dengue mosquitoes, by contrast, can breed in small water-holding containers located inside or near residential premises.
From an administrative perspective, Bahl said sustained vector-control measures were necessary to control dengue. These include spraying and preventing mosquito larvae from breeding. The warning places household checks alongside public vector-control operations, with the removal of stagnant water and monitoring of potential breeding sites forming part of the prevention effort.
Bahl was in Calcutta to deliver a lecture, where he also provided an update on an ICMR dengue vaccine trial. The phase-III trial is being conducted across 20 centres and has enrolled 10,335 volunteers. Recruitment was completed in December last year, after taking about six months longer than expected because of difficulties in finding volunteers willing to be vaccinated.
The trial is now in its two-year follow-up phase, with almost one year completed, Bahl said. It is double-blind, meaning neither participants nor researchers know which intervention a participant has received until the trial concludes. The vaccine is unlikely to be available before the next monsoon season, according to sources cited in the report.
