Why are dengue cases still rising in November?
Under normal circumstances, November's dry weather was supposed to cause the Aedes mosquito population to decline. But this year, around 150 dengue patients are still being hospitalised daily, illustrating a concerning picture of the vector-borne disease.
According to Directorate General of Health Services (DGHS), this year, around 25,774 dengue patients were admitted to different hospitals across the country till yesterday, with the death toll for the year at 97. Both infection and deaths are second highest since the first outbreak in Bangladesh in 2000.
At least 140 patients were hospitalised in the last 24 hours till 8am yesterday, of whom 30 are from outside Dhaka.
Experts pointed to late rain showers, and high humidity and temperature in October as main causes behind this situation.
Entomologist Prof Kabirul Bashar of Jahangirnagar University said normally, the population of Aedes mosquitoes depends on rainfall, as the insects breed in water that collects in containers after rainfall.
He said the situation will not drastically change in the next 15 days, since the capital experienced rainfall in the last week of October and in the beginning of November. Even if further rainfalls do not occur, the mosquito population will remain the same till the end of November, he said.
Additionally, climate change is disrupting the seasons, further exacerbating the problem. "We are experiencing early and late rain showers due to climate change," he said.
Entomologist Manzur Chowdhury, former president of Zoological Society of Bangladesh, said Dhaka city corporations have failed to take effective steps to control Aedes mosquitoes.
He also said the number of dengue patients for this year is actually higher than the numbers being reported.
Dr Md Nazmul Islam, director (disease control) of DGHS, said early monsoon and intermittent rain led to the high number of dengue patients this year. But the situation is better compared to 2019, when the number crossed the one lakh mark.
He, however, said that the dengue situation is now under control and will improve gradually.
After the dengue virus enters a community, it does not go away completely, as eggs remain viable for a long time, he explained.
Dhaka North City Corporation (DNCC) Chief Health Officer Brig Gen Jobaidur Rahman said they are continuing their drive against Aedes and Culex mosquitoes.
"We've tried a lot to make people aware, but we've decided to start taking action if they do not clean containers and their premises," he said.
Dhaka South City Corporation's spokesperson Md Abu Nasher said they are continuing to spray larvicide and adulticide every day, and are also fogging areas surrounding houses of dengue patients, after getting data from DGHS.
"We will conduct cleaning activities in 12 water bodies of DSCC from December 1, as Culex mosquitoes also proliferate during the dry season," he said.