Page 408 - e-Book

1. INTRODUCTION:

Globally mosquitoes are known to transmit more diseases that affect millions
of people than any other group of arthropods. The severity of infection and health threat

posed can be comprehended by WHO’s classification of mosquitoes as “Public enemy

number one” (WHO, 1996). Several life-threatening vector borne diseases i.e. protozoan
diseases as malaria, viral diseases as yellow fever and dengue fever and parasitic diseases as

filariasis etc. are caused by mosquitoes. Mosquito borne disease are prevalent in about 100
countries over the globe; and are known to infect 700,000,000 human’s annually of which

40,000,000 people belong to India (WHO, 1996; WHO 2009). Some of these diseases like
malaria caused by Plasmodium falciparum and dengue caused by dengue virus with adverse

conditions of dengue hemorrhagic fever or abnormal symptoms on central nervous system

account for serious public health threat for (Das et.al., 2007; WHO 2009). There are different
species of mosquito such as Anopheles, culex, Aedes that act as a vector for different

diseases like Chikungunya virus, Dengue Virus, Encephalitis virus, Malaria, Yellow fever,
Zika virus and many more (Jain and Kumar, 2018). The prevalence of these sepecies can be

contributed to their adaptive nature, as an ever-present insect this race shows ability to alter

their needs as per any new habitat (Murugan et. al., 2011). Apart from causing pathogenicity
in humans mosquitoes are also known to cause diseases like ‘fowl pox’ in chickens,

‘myxomatosis’ in rabbits, ‘rift valley’ in sheep and ‘encephalitis’ in horses and birds.
Extracted protein from Bacillus thuringiensis and Bacillus sphaericus, temephos,

organophosphates, methoprene are some of the most used larvicides. Economic feasibility of

these approaches is also poor as bacterial product has a high cost of production and
purification (Lacy, 2007). So mostly the chemical compounds are preferred as compared to

extracted proteins. The major use of chemical insecticide in recent days to control the
increasing number of vectors have a detrimental effect on beneficial insects and environment

both. Water logged places like drains and culverts, where mosquitoes breed and rest, are
treated with pyrethroids but the extreme use of chemical pesticides is leading mosquito

population undergo selection pressure due to which the mosquitoes are developing resistance

against synthetic insecticides (Jain and Kumar, 2018). Anopheles gambiae is DTT resistance
and hence over growing concern use of DDT has been banned (Muhammad et. al., 2021).

Anopheles coluzzii shows resistance to permethrin due to differential expression of
insecticide resistance gene CYP6Z1 on the X chromosome locus, increased activity of

Carboxylesterase COEAE5G suggest resistance to organophosphates (Mathur et. al., 1981).

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