Second worst dengue outbreak in 22 years

Infographic: TBS

The Bangladesh Directorate General of Health Services reported 923 dengue cases in the last 24 hours till Tuesday morning, bringing this year's total cases to 33,923.

During the 24 hours, two more dengue patients died. The death toll now stands at 120.

With the latest addition, this year's dengue cases and casualties became the second highest since 2000 when the government formally started keeping records on dengue. In 2000, 5551 dengue cases and 93 deaths were registered.

However, in 2019, the highest 1,01,354 dengue cases and 179 deaths were reported.

Although the Aedes mosquito-borne viral disease usually prevails between April to September every year, this year's October witnessed 17,831 dengue cases and 65 deaths in 26 days – a very rare situation. 

Last month, September, saw 9,911 dengue cases and 34 deaths.

Experts believe the prevalence of dengue will decrease in the next seven days as cyclone Sitrang has been a blessing in disguise for tackling the outbreak. The storm, coupled with tidal surges and heavy rainfall, washed away many habitats of Aedes mosquitoes. 

"Aedes mosquito breeding has been higher this year due to accumulation of water around houses owing to frequent intermittent rains amid changing climate. As a result, the dengue outbreak has been prolonged. Besides, we have failed in managing dengue hotspots," said Kabirul Bashar, medical entomologist and professor of zoology at Jahangirnagar University, told The Business Standard. 

The situation will improve soon as many mosquitoes have died in heavy rainfall and storms during cyclone Sitrang, he said.  

"As fever develops in human beings four to seven days after being bitten by the Aedes mosquito, we will have to wait a week to see the improved situation," the professor explained.

However, there is also a risk of increasing mosquitoes again if the flood waters do not recede within 15 days, he warned, saying that the accumulated water should be removed quickly so that mosquitoes cannot breed there. 

Kabirul Bashar also emphasised the continuity of mosquito-killing drives.

According to the Institute of Epidemiology Disease Control and Research, the severity of dengue is high this time due to multiple serotypes of dengue – DEN 1, 3 and 4. Physicians and health experts have cited comorbidity (simultaneous presence of two or more diseases in a patient) and late hospitalisation of dengue patients as the main reasons for the rising death toll.

About 64% of critically-ill dengue patients have died this year within three days of hospitalisation, according to the health directorate.

"The prevalence of dengue was lower in the past two years thanks to the Covid pandemic-related closures. It has increased this year amid reopening," Professor Dr Nazmul Islam, director of the Communicable Disease Control unit of the health directorate, told The Business Standard. 

He is hopeful the dengue outbreak will decrease at the beginning of the next month. 

"Two city corporations of Dhaka are continuing their drives to kill Aedes mosquitoes and the health directorate is providing treatment to dengue patients at the DNCC Covid Hospital in the capital."

Dr Nazmul Islam urged all to keep their house premises clean to prevent dengue. If anyone develops a fever, he or she must undergo a dengue test. Hospitalisation will be required in some cases, the physician added. 

Dengue is a viral infection causing a high fever and severe flu-like illness, according to the World Health Organisation. Patients may develop symptoms such as severe headache, pain behind the eyes, nausea, vomiting, swollen glands, muscle and joint pains, and rash. 

The Aedes aegypti mosquito is the main vector that transmits the virus to humans. Later, humans become the main carriers and multipliers of the virus as they serve as a source of the virus for uninfected mosquitoes, the WHO said.