Dengue infections surge even before peak season

The number of dengue infections usually starts rising in the country during the June-September period, but it has jumped sharply in May this year.

The number of dengue patients in the country increased from three in April to 43 in May 2021, while it has jumped from 23 in April to 163 in May this year.

The Directorate General of Health Services (DGHS) already warned the authorities concerned about the possibility of an increase in dengue prevalence this year.

And this warning has now become a reality as the initiatives taken by the two city corporations of Dhaka have not been enough to curb the mosquito breeding, entomologists and health experts said.

The Aedes mosquito, which is the main vector that transmits the dengue virus, usually breed in the country from June to September. 

Infographic: TBS

However, this year the density of Aedes mosquitoes has increased several times ahead of the season, said the entomologists expressing fear that this might cause an increase in the dengue infections.

According to a survey conducted by DGHS before the monsoon season this year, 24% of the larvae found in plastic drums were aedes larvae. In 2019, when the dengue infection was the highest in the country, this rate was 11.5%. In 2019, aedes larvae found on the submerged floors were 20%, which is about 24% this year.

Aedes larvae were found everywhere in the city, according to information on the combing operation conducted by the Dhaka North City Corporation. Entomologists fear that the density of Aedes may increase further after the rainy season begins.

According to a survey by the DGHS, the Breteau index, which measures the density of aedes mosquitoes, is a bit higher in Dhaka South this year compared to the previous years. In ward-45 of this city corporation, the density of aedes mosquito is 23.33% of the total mosquito found there. Besides, the density of aedes mosquitoes in wards 38 and 40 is 20%.

Generally, the density of aedes mosquitoes above 20% is considered risky.

"It is not possible to control dengue infection in the way the city corporations are trying to do it with a small number of staff. For this we need to increase community engagement. The more people can be made aware and involved in dengue control, the easier it will be to keep dengue at a tolerable level," Professor Dr Be-Nazir Ahmed, former director of disease control at DGHS, told TBS.

Fearing that the dengue situation could worsen this year, the public health expert said this year it has been raining a little even before the start of monsoon season and the number of dengue patients has been increasing before the peak season due to water logging.

Entomologist Professor Kabirul Bashar told TBS, "We warned the two city corporations earlier this year that dengue infection could increase compared to the previous two years."

"The mayors of the two city corporations of Dhaka are enterprising, but their initiatives will not be very effective if their manpower cannot be increased and councilors are not made aware of the problem," said Professor Bashar, who was involved in the survey conducted by DGHS.

He said the authorities should work throughout the year, not for just a few months, to control the aedes mosquito. Culex and Aedes mosquitoes should be controlled separately. For this, the two city corporations should take on different projects for 4-5 years.

Dr Fazle Shamsul Kabir, chief health officer of Dhaka South City Corporation, told The Business Standard that the list of dengue patients given by the DGHS contained substantial misinformation. Most of the patients mentioned in the list were found outside Dhaka. Besides, those who suffer from common fever are also included in the list of dengue patients.

Noting that only eight patients were found in Dhaka South in May, he said, "We found some patients in the Manda area, while no dengue patients were found in any other areas of the city. The Dhaka South City Corporation is regularly conducting drives, fogging, and spraying larvicide in the Manda area."

He also said the dengue outbreak will be minimal this year.

Brigadier General Md Jobaidur Rahman, chief health officer of Dhaka North, told TBS that the city corporation is working day and night to prevent the spread of the aedes mosquito.

"Hopefully we can control it this year. We are conducting various programmes in the community engagement including distribution of leaflets for raising awareness among ward councilors, housing societies, imams of mosques, school teachers. In future we will organise campaigns and road shows."

He said, "We currently have two dengue patients in Dhaka North. Wherever we find aedes larvae, we sue and fine the building owners. So far, there was nothing to worry about."

According to the DGHS, 14 patients were admitted to different hospitals across the country in the 24 hours till 8am on Tuesday.

So far this year, the highest number of dengue patients was admitted to hospitals in May –  163. The total number of dengue patients this year has reached 352.

According to DGHS, currently 48 dengue patients are receiving treatment in the hospitals in Dhaka and one dengue patient is receiving treatment outside the capital. No one has died of dengue this year.

The number of deaths caused by dengue in 2019 surpassed all previous records. According to the official estimate, 164 people died from dengue that year, while several lakh people suffered from it.

In 2020, when Covid-19 hit the country, dengue infections were in control. That year, seven people died of the disease.

In 2021, the number of dengue infections was the second highest – 28,429, while the virus caused 105 deaths.