With Covid-19 slowing down construction work, multi-storey buildings with holes and crevices perfect for mosquito breeding are left unattended
The Aedes mosquito-borne viral infection dengue is on the rise once again in Bangladesh, with 18 cases recorded daily on average in November.
In November, not the usual season for dengue, the health authorities recorded 546 cases of dengue infections, which is 47% of the total dengue cases recorded during the current year.
A total of 1,174 people were hospitalized with dengue across the country, including 1,033 in Dhaka alone, from January till November 30 this year, according to data compiled by the Directorate General of Health Services (DGHS).
Experts have dubbed the situation as worrying since the number of cases recorded in November is 235% higher than the 163 cases reported in October, as per data from the Health Emergency Operations Centre and Control Room of DGHS.
The re-arrival of dengue in Dhaka is particularly unwelcome this year, with the capital still reeling from the Covid-19 pandemic.
In 2019, Bangladesh experienced a massive dengue outbreak, when 101,354 people were hospitalized. According to the health authorities, the mosquito-borne disease killed 179 people last year.
What is the situation now?
Bangladesh recorded over 100 cases of dengue infections in January and the number of cases continued to come down till May. However, the cases started rising again in June.
The country recorded 199 cases in January, 45 in February, 27 in March, 25 in April, 10 in May, 20 in June, 23 in July, 68 infections and a death in August, 47 infections in September, 163 infections in October, and 546 cases in November, according to the DGHS.
Out of the 1,174 patients admitted with dengue at different hospitals, 90 were under treatment as of November 30. Among them, 76 were in Dhaka and 14 were outside Dhaka.
The IEDCR has so far received information on seven deaths and completed investigation into four deaths, out of which three have been confirmed as dengue related deaths. Among them, one death was confirmed in August and two others in October.
Nine areas at risk
At least 25 wards or nine areas under the two Dhaka city corporations are at risk of dengue infections, a government survey has found.
The Monsoon Aedes Survey 2020 by the National Malaria Elimination and Aedes Transmitted Disease Control Program of the Health Department found that six areas under Dhaka North City Corporation (DNCC) and three under Dhaka South City Corporation (DSCC) were more prone to Aedes mosquito infestation than the rest of the capital.
The survey, released in August, also mentioned that multi-storey buildings accounted for more than half of the city’s Aedes mosquito breeding grounds.
The Breteau Index (BI) measures the number of water-holding containers infested with larvae per 100 houses.
The highest BI score of 43.3 was found in Kalyanpur, Paikpara and Madhya Paikpara areas under Dhaka North ward 11.
Meanwhile, Khilkhet, Kuril and Nikunja areas of DNCC’s ward 17 along with Mir Hazaribagh, Dholaipar and Gandaria of ward 11 under DSCC scored 40 — the second-highest BI score across the city.
Shockingly, a whopping 51.34% of Aedes mosquito breeding grounds are in high-rises, whereas the figure for under-construction buildings is 20.32%.
What experts say
Entomologist Kabirul Bashar said that although the monthly dengue infections peak in either August or September in most years, this year is an exception.
“There are multiple reasons behind the sudden spike in dengue cases this year, at this time,” said Bashar, who is a professor of Zoology at Jahangirnagar University.
Citing a survey conducted by the university last month, he said the presence of mosquitoes was notable in most under construction buildings visited last month and it was because of the slow development of sites because of Covid-19.
“In most water reservoirs or the empty spaces allocated for lifts, we have found a huge amount of mosquitoes. On the other hand, every house has a place where water meters are placed. The places where a hole is created to set up the meter have leakages and almost 50% of those places were found with Aedes mosquitoes,” he said.
At the same time, in the areas where water supply is irregular, people preserve water in drums and many of those drums were found to be breeding places of mosquitoes, the professor pointed out.
The DNCC last month conducted a drive to contain Aedes mosquitoes. However, the sudden drives were not enough to contain dengue, he opined.
“The drives will continue throughout the year, following scientific methods and with the participation of people, if the city corporations really want to contain dengue transmission,” added the professor.