How prepared are we to fight mosquito-borne diseases?
Bangladesh is still reeling from the worst dengue outbreak in its history, even though the initial shock has passed. According to the official estimate, the mosquito-borne disease has so far claimed 75 lives across the country. The unofficial figure, however, stands at 155 and counting. Some 85,757 dengue patients have been hospitalised since January this year. The fear of a potential spread of the Zika virus disease—another mosquito-borne disease—from neighbouring India and Nepal has only added to our travails. Moreover, with winter—the peak season for the breeding of Culex mosquitos, known to carry viruses that can cause West Nile fever, filariasis, avian malaria and Yellow Fever—lurking around the corner, people are now more concerned than ever before about fighting mosquitos and the diseases they can spread. Conversations with experts and officials indicate that to successfully fight these diseases, all relevant sectors will have to chip in.
Since the dengue epidemic gripped the capital earlier this year, the two city corporations have imported new pesticides from abroad to accelerate the anti-mosquito drives. According to Dhaka North City Corporation (DNCC) Mayor Atiqul Islam, to make the fogging drives more effective, GPS trackers are being used to monitor the activities of the workers involved with fogging. Dhaka South City Corporation (DSCC) Chief Executive Officer Mustafizur Rahman has revealed that they have also brought in new pesticides from abroad and are going to recruit and train another few hundred workers to conduct the fogging drives. But how effective is fogging alone in eliminating mosquitoes? According to Professor Mahmudur Rahman, former director of the Institute of Epidemiology Disease Control and Research (IEDCR), while fogging drives are important, focus should also be given on larvicide in order to eliminate mosquitos.
The focus of anti-mosquito drives also differs when trying to contain Aedes and Culex mosquitoes. While Aedes larvae can be found in discarded tires and artificial water containers in houses and peri-domestic areas, Culex mosquitos breed in polluted water, especially in polluted lakes, canals and drains. Therefore, while the same pesticide will work to eliminate both Aedes and Culex mosquitoes, the areas where the focus of fogging drives should be directed at will be different.
While discussing about the diagnosis of Zika cases in India and Nepal, Prof Kabirul Bashar, a professor of entomology at Jahangirnagar University, said that Bangladesh should strengthen its disease surveillance systems. He also recommended that screening and, if required, quarantine setup should be installed at the major airports, to screen people who might show symptoms of the disease, especially those coming in from Zika-affected countries.
One might wonder, given the failure of the government in foreseeing and preventing this year's dengue outbreak, how capable it is of handling the potential spread a new mosquito-borne disease. While discussing the initiatives of the IEDCR, its director, Professor Meerjady Sabrina Flora, said that the airports are already equipped with screening booths where visitors from Zika-prone countries can be tested and diagnosed, adding "although the booths are not functioning currently, they can be made operational when necessary." She also added that the IEDCR has strengthened their surveillance of diseases like dengue and Zika, and that currently there is no reason to worry about Zika.
But the question remains, how equipped are the hospitals to test potential Zika patients should it become necessary? Prof Flora said that IEDCR is equipped to diagnose Zika and that other hospitals should have the required machines to test patients for the disease. She also added that these hospitals have not currently been advised to stock reagents in order to prevent unnecessary testing. According to her, it does not take a long time to bring in reagents.
Unfortunately, even though entomologists have a very important role to play in all this, neither of the two city corporations have any. When asked about it, both sides, however, confirmed that they are soon going to recruit specialists in these positions. The DNCC mayor also added that they are forming a consultation group consisting of renowned entomologists in order to expedite their efforts to combat mosquito-borne diseases.
Although the two city corporations of Dhaka have taken multifaceted measures to combat mosquito-borne diseases, these measures are only Dhaka-centric, while mosquito-borne diseases have reached the far corners of the country. According to Prof Kabirul Bashar, a more comprehensive initiative needs to be taken by the authorities, especially the LGED ministry, involving the people at the Union Parishad levels, to plan and implement well-rounded programmes to eliminate mosquitoes, with a special focus on larvicide.
A similar thought has been echoed by Prof Mahmudur Rahman, who views the initiative to fight mosquitoes as a "multisectoral issue" and suggested that in order to effectively prevent such an outbreak in the future, the government must now form an After-Action Review body to assess the failures and lessons learnt from this year's outbreak, so that effective preventive measures can be taken in time. He also suggested that in order to check the effectiveness of the ongoing anti-mosquito drives, the authorities can study the Breteau Index (number of positive containers per 100 houses inspected), so that additional measures to destroy mosquito-breeding grounds can be taken if required.
From this years' experience we have seen that urban planning has also an important role to play in combating mosquito-borne diseases. According to Prof Mahmudur Rahman, while planning long-term strategies to fight mosquitoes, the government and city authorities must focus on city plans that leave zero space for mosquito larvae breeding, and that facilitates anti-mosquito drives. He said that even buildings should be designed in such a way that they do not leave room for waterlogging that can turn into mosquito-breeding grounds.
What is apparent from these comments is that fighting mosquito-borne diseases is not a walk in the park; it is not even a one-off or seasonal stint. With global warming and changing weather patterns leading to more favourable breeding environment for mosquitos, it will take the efforts of the entire nation to fight the multiple diseases that can be carried by this insect. While policymakers will need to formulate effective strategies and policies to control and prevent these diseases, executing authorities like the two city corporations down to the Union Parishads will have to effectively implement these policies and programmes.
Institutions like the IEDCR and DGHS, along with other specialised bodies such as ICDDR,B, have to be vigilant and strengthen their surveillance systems to detect these diseases and act as early warning mechanism, so that effective measures can be taken in time to root out the diseases before they become a major threat to public health. The media should also keep track of the progress of all the programmes that are being initiated and make every stakeholder accountable by reporting their progress.
And the common people have to play the most important role in eliminating potential mosquito-breeding grounds by keeping their houses and surroundings clean. This year's outbreak should be a learning experience for all, and we must all assess what went wrong and identify the gaps in our systems and rectify them immediately. The two city corporations of Dhaka and the IEDCR have claimed to have initiated a number of steps but it remains to be seen how much of these is actually implemented, and to what effect.
Tasneem Tayeb is a member of the editorial team at The Daily Star. Her Twitter handle is @TayebTasneem.