Malaria is a vector borndisease in which Plasmodium sp. (a protozoa) transmitted in human body causes a high chilled fever and sometime sever heath issues that causes death.In tropical countries like India, Sri Lanka, Bangladesh, South Africa etc. is causes severe malarial health issues. The vector is most responsible for is epidemiological nature of disease. Moreentomological study about vector, studied its morphology,physiology, genetic,ecological adaptations,life cycle, sensitivity to chemicals, larval stages, habitat etc., they try to develop the curing drug, eradicate methods, repelling-creams,and find certain chemical that affect its larval development, also develop biological control methods.

When we see the malarial censes of last few decades we find that the severity of low in recent years but after 2013 the number of cases increases however death isquiet low and to know its nature of epidemiology in future many researcher investigate the effect of climate changes on vector (Mosquitoes) as well as Plasmodium sp.  There is many Physical, chemical, biological methods to control, escape from malarial bite. Every Country Government try to control Mosquito bite immediately because infection begins with that single this causes.

 In Indian society to avoid mosquitos Insecticide-treated mosquito nets, mosquito repelling cream, mosquito coils and chemical, fast card, chemical fumigation are frequently used. These chemical methods includes lots of organic- inorganic chemical they adverse effect on mosquitos but recent researches indicate that these chemicals also harms other life forms, affect biodiversityand human health. In changing scenariomosquitoes also develop resistance to these chemicals, that’s why use of high dose also injurious to human health. However WHO recommended 12 mosquitoes eradicating chemicals but they provide insecticide resistance to mosquitos.Most of chemicals are Picaridin,  Pyrethroids,Pyrethrum, DEET or N,N-Diethyl-meta-toluamide or diethyltoluamide, Dibutyl hydroxyl toluene (BHT), Piperonylbutoxide (PBO), N-(2-ethylhexyl)-bicyclo-(2,2,1)hept-5-ene-2,3-dicarboximide, DDT, Malathion, Lambda-cyhalothrin, Deltamethrin, d-d, trans-cyphenothrin, Deltamethrin, etc. these chemicals are fumigated indoor or outdoor with the help of fumigants- aerosols, dust etc.human inhale these chemicals they are ultimate biological poison affect health.Malathion is class- III pesticide is also known as slightly hazardous and diesel exhaust‘Carcinogen’ declare by WHO.

WHO recommended limit of insecticide for mosquitoes

(A). for treatment to mosquito- net

(B). for fogging (spraying) against mosquitoes

Health effect

Application in excess amount insecticide in fogging causes itching, prickling sensations on skin, facial flushing and swelling, convulsions, tremors, asthma, sneezing, nasal congestion and nausea in human body. However small amount of DDT application permitted under Stackhome Convention for health issues but not for agricultural use. Its more amount accumulate in different trophic level, through food chain it accumulate in human causessevere health problems. Mosquitoes fogging mostly contains malathion and diesel, dust etc. that affect pregnant women, small children and old people make susceptible to asthma attack,allergic reaction in lungs and respiratory tracts. A long time exposure to this leads temporary swelling of the corneas.Mosquito repelling liquid contains DEET (N-N-Diethyl-meta-toluamide) mosquitoes avoid its smell, has neurological effects on mosquitoesbut not killed them. Findings indicate that it causes burning eyes, headaches, and breathing difficulties and prolong exposure causes hormonal imbalance like hypo/hyper thyroidism.

Ecological challenges

After fumigation these chemical insecticides comes in ecosystem and hyper accumulate in different trophic levels of our food chain. Its accumulation in adipose tissues in higher consumer and causes adverse biochemical changes this problem called biomagnification. During spray of these chemical many other insect species also died which are not harmful. These chemical pollute water bodies, soil pollution, and affect biodiversity.

Development of Mosquito resistance against insecticides

The capability of mosquitoes to resist insecticides signifies a severe threat to the prevention of   malaria, dengue etc.  scientific study investigated that it develop due to long time use of same insecticide in a particular area through the natural selection mosquito developed  several, complex resistance mechanisms-in particular, increased metabolic detoxification of insecticides and decreased sensitivity of the target proteins-or genes are likely responsible for insecticide resistance. Gene overexpression and amplification, and mutations in protein-coding-gene regions, have often been involved in this. However, no comprehensive understanding of the resistance mechanisms. In a recent study found Pyrethroids resistant to both type I and type II in Brazilian strain of Aedes aegypti with high level, detected two mutations (V410L and F1534C) in the sodium channel drastically reduced the sensitivity of mosquito sodium channels expressed for both type pyrethroids insecticide.

Future prospective

Application of Integrated Vector Management (IVM) to avoid the malarial bite. Biological method applied with other eradicating tool give better response. Recently in China and Japan developedgenetically Modified sterile male mosquitoes and spread in native population where they matting but not produce offspring. So that population going to decrease. However more researches require to understand its mechanism and prevention.