21/06/2024
Concerns Rise Over Environmental Impact of Chemical Sprays in Khyber Pakhtunkhwa's Anti-Dengue Campaign:
Zeenat Bibi
The Health Department of Khyber Pakhtunkhwa, in collaboration with other line departments, has initiated anti-dengue activities as part of the approved Dengue Action Plan 2024. Dengue, caused by the Aedes aegypti mosquito, poses a significant threat due to its preference for breeding in various containers with clean water, complicating control efforts.
The control of dengue has become increasingly challenging due to factors such as urbanization, population growth, international travel, and inadequate vector control programs. Environmental conditions, particularly in resource-limited settings, exacerbate the transmission of dengue.
The Dengue Action Plan 2024 of Khyber Pakhtunkhwa focuses on a three-pronged approach to control the disease. This includes mechanical sweeping to eliminate potential larval breeding sites, chemical fogging, and Internal Residual Spray (IRS).
Salahuddin Khan, an entomologist in the Health Department, detailed the use of chemicals in anti-dengue efforts. Chemicals such as Fendona 10% SC are mixed with water and sprayed as IRS for indoor anti-dengue techniques. Additionally, chemicals like Icon 1.5 or 2.5% are used for fogging in houses, streets, and dengue hotspots. Chemifos chemicals are employed to treat stagnant water sites for larvicidal activities.
Khan emphasized that globally, best practices prioritize environmental management and biological control over chemical use. Chemical spraying is recommended within standard limits and after confirming dengue cases in the area, typically at dawn and dusk.
However, concerns have been raised about the political backing and irrational use of sprays and fogging in anti-dengue campaigns. Excessive chemical use has led to adverse effects on the environment, including a reduction in flies and bees, essential pollinators for crop production.
According to the World Health Organization, mechanical sweeping of larval breeding sites is the most effective method of dengue control, with an efficacy rate of about 90%. In contrast, IRS and fogging have efficacy rates of only 6% and 4%, respectively.
Research indicates that the excessive use of chemical insecticides has resulted in widespread resistance in Aedes aegypti mosquitoes, further impacting human health. Additionally, insect repellents may have hazardous interactions with biological systems, potentially generating harmful effects.
Biological control methods, such as introducing larval-eating fish and Sterile Insect Technique (SIT), offer environmentally friendly alternatives to chemical control. However, despite these alternatives, the harmful effects of chemical sprays on the environment and human health remain a concern.
Qaisar Zaman, an Assistant Professor of Biology, highlighted the detrimental effects of anti-dengue chemicals on pollinator insects and natural scavengers. He cautioned that chemical runoff from treated areas can contaminate water sources, endangering aquatic ecosystems and non-target organisms.
The use of chemicals such as Fendona 10% SC, containing Alpha-Cypermethrin, poses significant risks to fish, bees, and aquatic insects. Despite training efforts, field staff often manually mix chemicals, further exacerbating environmental and health risks.
In conclusion, while anti-dengue efforts are crucial, there is a pressing need to balance control measures with environmental and health considerations. Implementing sustainable and environmentally friendly strategies is essential to effectively combat dengue while minimizing adverse effects on ecosystems and human health.
