In the wake of the massive dengue outbreak in Bangladesh, Dr Arun Kumar, head of Environmental Science at Bayer South Asia, a branch of global giant Bayer - a life science company with more than 150-years history, and core competencies in the areas of healthcare and agriculture, speaks to Dhaka Tribune's Syed Samiul Basher Anik about the challenges involved in tackling the dengue outbreak, and the importance of community-based initiatives in containing it
What are the challenges involved in tackling dengue?
Dengue has reached a pandemic proportion, and has become a major public health concern. According to the World Health Organization (WHO), dengue is endemic in over 100 countries with 50% of the world population at risk. South Asia is the worst-affected region.
The primary vector of dengue virus is the Aedes Aegypti mosquito. Widespread infrastructural activities, and urban expansion without prior health impact assessments, poorly designed irrigation and water systems, improper solid waste management, deforestation, increased international travel and trade, and climate change etc. have contributed to their proliferation.
Vector control measures include using insecticides and community campaigns. Some measures fall short in terms of cost, delivery, insecticide resistance, sustainability, and environmental safety.
Tackling dengue requires a multipronged, integrated vector management (IVM) strategy, which emphasizes environmental management, and biological control along with judicious use of chemical methods. One of the simplest ways to reduce mosquito breeding is better urban planning, and careful environment management. It is easier to control the Aedes mosquito in its breeding stage than during adulthood.
What kind of insecticides does Bayer produce to kill Aedes mosquitoes and how effective are they? How many samples have you sent to Bangladesh?
Bayer has been providing effective vector control solutions to public health globally for more than 60 years. Bayer advocates an Integrated Vector Management approach to all stakeholders, which includes appropriate use of larvicides, indoor residual sprays, space sprays, and bed nets. Bayer has been instrumental in providing effective solutions across these categories for sustainable vector control interventions in the communities where people live, work, and play.
Bayer has Deltamethrin 2% EW (brand name Aqua K-Othrine) for effective control of the Aedes mosquito. Deltamethrin comes with patented technology that eliminates the need for using oil-based diluents for space spray application against mosquitoes. It is a WHO prequalified (PQ listed) product which reflects its safety, efficacy, and environment-friendliness. We at Bayer recommend Bangladesh authorities use Aqua K-Othrine to combat this mosquito.
The other products are Aqua Resigen (Permethrin and s-Bioallethrin), and Kingfog (Deltamethrin 1.25 ULV) for space spray, Stayricide (Triflumuron) for larvicide, and Ficam (Bendiocarb) for indoor residual spray.
Along with Bayer’s focus on innovations and development of impactful products in the field of vector control, Bayer focuses on training, and education initiatives in collaboration with public health authorities, and local communities.
What did Bangladesh’s city corporation authorities want to know from Bayer?
The city corporation authorities reached out to several companies to demonstrate their existing and new innovations to curb the outbreak. Bayer participated to showcase space spraying solutions for mosquito control, and its efficacy.
To identify the best and effective solutions for dengue control, demos need to be conducted in accordance with the protocols specified by WHO. These require that the adult mosquito cages be suspended 1.5 meters above the ground. Most importantly, trials should be conducted on the Aedes mosquito. Space spray chemicals should be applied using suitable fogging machines with proper calibration to ensure the right discharge rate.
Do you think only mosquito repellents can help prevent dengue outbreak? If not, what can the public do?
It is important to note that around 80% of all mosquito species (including Aedes) is in the larval breeding stage, and only 20% are adults. For effective control, mosquitoes need to be eliminated at the larval stage. The Aedes mosquito should not be allowed to breed inside, and near homes. Excess water should be drained out from containers, and changed regularly. Flower vases should be kept clean, and unused items should be discarded or destroyed. These are simple steps every home can adopt to discourage the breeding of this dangerous mosquito.
Can you talk about the importance of surveillance in dengue management? Also, how can community-based initiatives help in reducing the dengue outbreak?
Surveillance can play an important role in dengue management. It needs to focus on human cases, virus, entomological, and ecological surveillance. If community participation could be integrated into source reduction efforts, it will support public health authorities to carry out effective vector control.
Policymakers, government, and local communities need to work together to curb dengue. Inter-sectoral links are also necessary between departments that look into urban development, agriculture, and water resources, as together they can monitor breeding areas.