Insecticide For Dengue Mosquitoes

Dengue is a dangerous mosquito-borne disease that affects millions of people all around the world. Dengue fever is a virus and the only way to protect yourself from this potentially fatal disease is to reduce the amount of contact with Aedes species mosquitoes.

Insecticide For Dengue Mosquitoes

Due to the unavailability of an effective vaccine for dengue, one of the best approaches to control the spread of dengue is by managing the vector and its breeding sites. Various strategic approaches have been promoted to control mosquito vectors, including chemical control (indoor residual spraying, mass fogging, use of household insecticides), biological control (use of mosquito predators, release of specific genetic modified mosquitoes), source reduction and public education. Larvicidal chemicals, such as temephos and Bacillus thuringiensis israelensis (Bti), and adulticidal chemicals in ultra-low-volume sprays and fogging are widely used to control the spread of the disease. An estimated 2.5 million tons of pesticides are used annually [35]. There are four main classes of insecticides commonly used for vector control programmes: pyrethroids, organophosphates, organochlorines and carbamates.

Organochlorines

Organochlorines (OCs) are chlorinated hydrocarbons that were developed in the early 1940s, and this category includes dieldrin, lindane, chlorobenziate, chlordane and the most popular chlorinated insecticide of all time, dichlorodiphenyltrichloroethane (DDT) [36, 37]. OCs are effective in controlling malaria, but they persist in the environment as a result of their high lipid solubility [38, 39]. They are subdivided into two subclasses, namely DDT-type chlorinated insecticides and chlorinated alicyclic insecticides, based on their distinct mechanisms and target sites [38]. DDT-type insecticides target the voltage-sensitive sodium channel (Vssc) in mosquitoes. Loughney et al. [40] described that the α-subunit of the sodium channel contains four homologous domains (I–IV), with each domain characterised by six transmembrane segments (S1–S6). Segments S1–S4 constitute the voltage-sensing domain whereas segments S5 and S6 form pore domains along with the intervening pore loop. The function of Vssc is to initiate and propagate action potentials in response to membrane depolarisation by opening and closing the channel [41]. DDT exerts its toxicity by impeding the sodium channels, hence retaining the conduction of sodium ions even after membrane repolarisation [42,43,44]. DDT acts mainly on the peripheral nervous system causing ‘DDT jitters’ where the muscles twitch throughout the body and the appendages. Exposure to DDT gradually leads to excitatory paralysis and subsequent death of the insects [44]. Chlorinated alicyclic insecticides, in comparison, bind at the γ-aminobutyric acid (GABA) molecule in the GABA chloride ionophore complex, resulting in hyper-excitation of the nervous system that subsequently leads to chlorine channel closure [45, 46].

Organophosphates

Organophosphates (OPs), a phosphoric acid derivative, are the most toxic insecticides and detrimental to both mammals and insects. The most commonly used OPs are malathion, parathion, chlorpyriphos and diazinon. OPs were introduced in the 1960s to replace the usage of OCs with their many adverse effects and long persistence in the environment [39]. OPs interfere irreversibly with acetylcholinesterase (AChE) activity by phosphorylating its serine residues, resulting in hyper-excitation and disruption of neurotransmission in the central and peripheral nervous systems [37, 47]. This enzyme hydrolyses acetylcholine and causes repolarisation of basal plate in neuromuscular connections in preparation for the arrival of the new impulses [37]. Hence, the acute symptoms of poisoning with OP insecticides are muscle cramps, paralysis of respiratory muscles, convulsions and eventually death [36, 48].

Carbamates

Carbamate insecticides are derivatives of carbamic acid. The carbamate insecticides, such as carbaryl, carbofuran, propoxur and aldicarb, exhibit similar effects as the organophosphorus insecticides by inhibiting cholinesterase activity [49]. Nonetheless, the toxic action of carbamates can be reversed whereas the action of OPs is irreversible. In addition, the toxicity of carbamates is rather short as the residue of carbamylated serine is less stable, where decarbamylation tends to split the carbamyl moiety from the enzyme [50].

Pyrethroids

Pyrethroids are the synthetic analogues of natural insecticidal esters of chrysanthemum acid, called pyrethrins, which are categorised into types I and II based on their physical properties and toxicities. These insecticides have been widely used for the control of disease vectors for more than three decades [51]. The understanding of pyrethroids is complicated by two distinct intoxication syndromes. Type I pyrethroids (permethrin, tetramethrin, allethrin, phenothrin) lack an α-cyano group, and exposure causes tremor type syndrome by changing the conformation of the sodium channels for prolonged channel opening [51,52,53]. On the other hand, type II pyrethroids (cyfluthrin, cyhalothrin, deltamethrin, cypermethrin) possess an α-cyano-3-phenoxybenzyl moiety which produces choreoathetosis-salivation syndrome by modulating GABA levels and subsequently affect chlorine channels [51, 53, 54]. Type II pyrethroids have similar effects on sodium channels as type I pyrethroids, but with a lower amplitude of action potential. Type I pyrethroids give rise to repetitive discharges of sodium channels [38]. Previous studies have reported that the neurotoxicity of pyrethroids could be related to abnormal voltage-gated calcium regulation [52]. Certain pyrethroids, including cyfluthrin, cyhalothrin, cypermethrin, deltamethrin and permethrin, promote excessive calcium ion influx due to the reversed sodium–calcium exchange

Insecticide For Dengue Mosquitoes

Dengue mosquitoes are a serious threat to society. These pests can carry dengue fever, which can be fatal if left untreated.

To protect your family, it is important that you use an insecticide that is designed to target dengue mosquitos specifically. This will help you get rid of the dengue mosquito population in your home or yard without harming any other animals or people.

There are many different insecticides available on the market today, but only a few have actually been proven to be effective in killing dengue mosquitos. It’s important that you choose one that has been tested and approved by the U.S. Environmental Protection Agency (EPA).

List Of Insecticide For Dengue Mosquitoes