Mosquito coil smoke: A serious human health hazard

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Md Abdulla Al Mamun :
Pollutants are the major causes of death especially for the people with specific physiological conditions such asthma, allergy etc. An estimated 7 million people died worldwide in 2012 alone due to the exposure of air pollutants. People nowadays are generally taking different types of protective measures to evade from the exposure of pollutant such as taking musk, staying inside the room as possible and etc. But a lion share does not know the severity of house hold air pollutants on public health. An estimated 4.3 million people in 2012 died prematurely from illness attributable to the household air pollution. The considerable amount of indoor pollutants come from cooking and heating homes using solid fuels, cigarette smoke and smoke from mosquito coil.
Mosquito coil (MC) is a slow-burning structure made mainly of insecticides along with inert materials such as wood floor, coconut shell powder and starch etc. Pyrethroid (insecticide) is the main active ingredient of MC. Among the several types of pyrethroids, allethrin is used in almost all brands of mosquito coil in South Asian countries. Allethrin is a type of neurotoxin, causing paralysis of insect’s organs but safe for mammals use for lower doses.
Subtropical climate, poor drainage system and dense population are triggering the mosquito pressure day by day in Bangladesh. To get rid of mosquito attack, middle and lower income groups are regularly using MC because of its lower price, simplicity to use and portability. Thus a huge number of people are undesirably exposing themselves to toxic fine particles and free radicals present in the smoke of MC and are subjecting to various health complications regularly. During overnight burning of MC, subjects at close proximity are exposed to sub-micrometer particle metal fumes, free radicals and vapors from smoke which ultimately reaches to the alveolar region of lung leading to irritation of the upper respiratory tract. Prolonginhalation of MC smoke is also correlated with asthma in children. It has been reported that MC smoke is responsible for rapid declination of cilia from respiratory epithelial lining. Cilia are slender, microscopic, hair-like structures, trapping foreign particles and microorganisms. Therefore, people with deciliated respiratory tract are more prone to chronic obstructive pulmonary diseases (COPD) and microbial infection.
Recent research in the Protein Science Lab, Department of Genetic engineering and Biotechnology, University of Rajshahi, Bangladesh has shown that prolong exposure of allethrin based MC causes severe form of emphysema (respiratory disease) and hyperplasia (over tissue growth) in the peripheral region of lung-prominent feature of COPD. Lung consists of numerous tiny sacs, called alveoli, which allow oxygen and carbon dioxide to move between the lungs and bloodstream. Emphysema is characterised by severe destruction of alveoli which lead to the formation of large air pockets that traps air resulting shortness of breath — the critical feature of COPD. Over tissue growth to compensate ongoing destruction of alveolar wall reduces air passing capacity through air way which also causes shortness of breath and requiring nebulizer in severe condition. COPD affects 329 million people in 2013 worldwide though cigarette smoking holds lion share of it. In 2013, it resulted in 2.9 million deaths. More than 90 per cent of these deaths occur in the developing world. It resulted in an estimated economic cost of $2.1 trillion in 2010.One study in India indicates that MC smoke induces elevated reactive oxygen species (ROS) level which impairs the balance between proteases and antiproteases (enzyme) defense system of the body and develop emphysema.
Recent reports raise concern among the people that the smoke of MC is a carcinogenic (cancer causing) substance. Chinese researchers show that employees working in MC manufacturing industry for nine years are suffering from lung cancer.
Another study in Taiwan shows that the people using MC are more prone to develop lung cancer. This study was conducted with 147 primary lung cancer patients and 400 potential controls. MC smoke exposure was more frequent in lung cancer patients than controls (38.1 per cent vs.17.8 per cent).
Long term inhalation of the smoke of MC leads to the alteration of the biochemical profile of blood such as hemoglobin level. Elevated levels of urea and creatinine have been reported in subject (rat) exposed to MC smoke. The presence of these substances in blood at higher portion or level is the key feature of kidney failure. MC smoke is also significantly correlated with elevated activity of some hepatic enzymes such as serum glutamic oxaloacetic transaminase (SGOT) and serum glutamic pyruvic transaminase (SGTP), indication liver injury. Inhalation of MC smoke alters the activity of body’s immune system by increasing white blood cells (WBC) count. These cells provide body’s defense and their over presence indicates that the body is suffering from infection, stress, inflammation, trauma, allergy, etc.
MC smoke is considered as a potent air pollutant in indoor environment, responsible for various organs failure including lung, kidney, liver etc along with impaired body’s system including blood circulation and immune system. One MC, upon burning, produces such amount of particulate matter equivalent to that of 75-137 cigarettes. However, toxicities associated with the inhalation of this hazardous substance yet not been able to receive enough attention both from policy makers and general public. Therefore, the following recommendations would be effective to find sustainable and healthy way to get rid of health complications from using MC.
1. People should use safe and effective alternative other than MC such as mosquito curtain to protect mosquito pressure.
2. Safe and effective biochemical compounds (insecticide) should be explored to produce MC with higher safety and activity.
3. MC should be used in open room with proper ventilation.
4. Awareness should be built among the people about the toxicological effects of current MC on public health.
5. Long time exposure of MC should be avoided. n

(Md Abdulla Al Mamun is a research assistant, Protein Science Lab, Department of Genetic Engineering and Biotechnology, University of Rajshahi, Bangladesh)

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