According to Greater Chennai Corporation data, the city had reported as many as 2,200 dengue cases last year, out of which 566 were reported in October alone. However, of the 90 cases reported this year, only 19 cases were reported so far this month. This is a decrease of 95.90 per cent.
Of the 90 cases, 24 were identified at government hospitals and the remaining were identified at private hospitals. However, the civic body claims no death recorded due to dengue this year.
“Usually, dengue cases will start to surface in June every year and reach its peak in October before coming down again once the Northeast monsoon commences. However, we did not see any spurt in the number of dengue cases this year,” S Selvakumar, chief vector control officer, Greater Chennai Corporation, said. When asked the reason for the steep fall in dengue cases, Selvakumar explained that the city did not receive significant rainfall during southwest monsoon, which would have affected the proliferation of aedes mosquitoes.
“During the southwest monsoon, the city would receive light rainfall, which would increase mosquito reproduction. On the other hand, mosquito eggs and larva will be washed out during heavy rains in the
Northeast monsoon season,” he added.
The Chennai Corporation also reckons that the disinfection measures carried across the city against COVID-19 spread would have controlled mosquito reproduction apart from healthy and immunityboosting diets followed by wary residents. Shut down of schools and other public places prevented further spread of the dengue virus.
Selvakumar suggested that wider research should be conducted to understand the sudden decline in the number of dengue cases, even though the civic body could not do dengue prevention works as the field
officials were stuck with COVID-19 related works. “Research by educational institutions wou ld help the civic body in understanding more about the mosquitoes apart from strategising in future. Vector density in the city waterways is also much lesser than the previous year,” he said.