Metrorail project areas at higher dengue risk

Safety measures from keeping home windows shut to using mosquito nets and keeping flowerpots clean could not save Rina Alam, who lives along the Metrorail project area in Mirpur-11 in Dhaka, from getting dengue.   

She has been suffering from the Aedes mosquito-borne infection from the day before Eid. Last year her daughter got infected with dengue. 

Rina Alam is an example of tens of thousands of people living along the project area. Some have been suffering from dengue fever while others are having to fend off attacks by Aedes mosquitos. 

A recent government survey has also found a concentration of virulent Aedes mosquitos in the Metrorail project areas. 

The study by the disease control unit at the Directorate General of Health Services (DGHS), found that 40 percent to 60 percent of the mosquito larvae in project areas are of the Aedes variety and can propagate dengue. 

In the survey carried out between July 31 and August 4 in 14 areas in the capital, the DGHS found the Breteau Index – a way of measuring the level of mosquitos – at over 20 in 12 of the areas. 

Entomologist Khalilur Rahman of the disease control unit told The Business Standard that there is a high risk of getting the infection if the Breteau Index is found to be over 20 in an area. 

Work on the Metrorail project is underway between Uttara and Motijheel via Pallabi, Mirpur and Farmgate. The disease control unit carried out the survey at Mirpur-12, and included the project area to the list of areas at risk of the Aedes mosquitoes. 

Experts say that big development projects such as the Metrorail are major breeding grounds for Aedes mosquitoes. Local people say that neither the city corporations nor the Metrorail authorities use insecticide on stagnant water in project areas. 

“The mosquito menace has increased recently in our area. It was far lower earlier,” Fahima Karim Pushpita, a resident of Pallabi for 25 years, told The Business Standard. 

“Water collects in the pits and holes in the Metrorail construction sites. Though the city corporations are seen to use insecticides on roads and back-alleys, but they are never seen clearing stagnant water or using insecticides in project areas.”

Professor Kabirul Bashar at the zoology department of Jahangirnagar University said Aedes mosquitoes will breed wherever there is stagnant water. 

“It is very hard to prevent waterlogging in the Metrorail project areas. The waterlogged pits cannot be filled because the construction is ongoing. That is why mosquito breeding in the pits has to be stopped by using insecticides and bleaching powders. If it continues, the situation will take a turn for the worse next year.”  

During his recent visit to Dhaka, BN Nagpal, senior entomologist for the Southeast Asia region of the World Health Organization, said that Aedes mosquitos can breed in clear water. 

“Infrastructure projects are a major source of larvae of Aedes mosquitoes. Dengue prevalence could be reduced by 40 percent if Aedes larvae are destroyed in the infrastructure projects.” 

He suggested routine surveillance so that there is no waterlogging in project areas, and called for punishing project authorities if they do not make an effort to restrict breeding grounds.   

The Dhaka Mass Transit Company Limited, a government organisation, has been implementing the project. When contacted, MAN Siddique, project director of the company, refused to make any comment over the phone on this issue. He suggested that the reporter come to meet him in person at his office. 

The disease control unit holds mosquito surveys three times a year – first at the beginning of the rainy season, then during the rainy season, and finally at the end of the season. 

After the first survey in March this year, the unit had forecast a rise in the mosquito menace along with an increased risk of dengue. 

Then the unit carried out a regular survey between July 17 and 27 when they found a 14 percent increase in the mosquitos in the two city corporation areas in Dhaka. 

During this period, dengue cases broke all previous records, prompting the authorities to go for the additional survey.

The disease control unit described the Kalshi ECB Chattar and the Bhasantek slums less at risk because it found fewer than 20 percent larvae in the areas.