 | |
 | |
 | |
| Names | |
|---|---|
| Preferred IUPAC name (S)-Cyano(3-phenoxyphenyl)methyl (1R,3R)-3-(2,2-dibromoethen-1-yl)-2,2-dimethylcyclopropane-1-carboxylate | |
Other names
| |
| Identifiers | |
3D model (JSmol) | |
| 6746312 | |
| ChEBI | |
| ChEMBL | |
| ChemSpider |
|
| ECHA InfoCard | 100.052.943 |
| EC Number |
|
| KEGG |
|
| RTECS number |
|
| UNII | |
| UN number | 3349 |
| |
| |
| Properties | |
| C22H19Br2NO3 | |
| Molar mass | 505.206 g·mol−1 |
| Density | 1.5 g cm−3 |
| Melting point | 98 °C (208 °F; 371 K) |
| Boiling point | 300 °C (572 °F; 573 K) |
| Pharmacology | |
| P03BA03 (WHO) QP53AC11 (WHO) | |
| Hazards | |
| GHS labelling: | |
  | |
| Danger | |
| H301,H331,H410 | |
| P261,P264,P270,P271,P273,P301+P310,P304+P340,P311,P321,P330,P391,P403+P233,P405,P501 | |
Except where otherwise noted, data are given for materials in theirstandard state (at 25 °C [77 °F], 100 kPa). | |
Deltamethrin is apyrethroidesterinsecticide. Deltamethrin plays a key role in controllingmalaria vectors, and is used in the manufacture of long-lasting insecticidalmosquito nets; however, resistance of mosquitos and bed bugs to deltamethrin has seen a widespread increase.
Deltamethrin is toxic to aquatic life, particularly fish. Although generally considered safe to use around humans, it is stillneurotoxic. It is anallergen and causesasthma in some people.
Deltamethrin is a highly effective insecticide. It is used, among other applications, for the production oflong-lasting insecticidal nets (LLINs), which, along with indoor residual spraying (IRS), are the main vector control strategies recommended by the World Health Organization (WHO) for the management of malaria.[1]
Deltamethrin plays a key role in controllingmalaria vectors, and is used in the manufacture of long-lasting insecticidalmosquito nets. It is used as one of a battery of pyrethroid insecticides in control of malarial vectors, particularlyAnopheles gambiae, and whilst being the most employed pyrethroid insecticide, can be used in conjunction with, or as an alternative to,permethrin,cypermethrin andorganophosphate-based insecticides, such as malathion and fenthion. Resistance to deltamethrin (and its counterparts) is now extremely widespread and threatens the success of worldwide vector control programmes.
Deltamethrin is a pyrethroid composed of a single stereoisomer, of a possible 8 stereoisomers, selectively prepared by the esterification of (1R,3R)- orcis-2,2-dimethyl-3-(2,2-dibromovinyl)cyclopropanecarboxylic acid with (alpha,S)- or (+)-alpha-cyano-3-phenoxybenzyl alcohol or by selective recrystallization of the racemic esters obtained by esterification of the (1R,3R)- orcis-acid with the racemic or (alpha-R,alpha-S, oralpha-R/S)- or + or − alcohol.
Resistance has been identified in several insects, including important vectors of malaria like the mosquitoAnopheles gambiae as well as non-disease carrying pests like bed bugs.
Methods of resistance include thickening of the cuticle of the insect to limit permeation of the insecticide, metabolic resistance via overexpression of metabolizingcytochrome P450 mono-oxygenases and glutathione-S-transferases, and theknockdown resistance (kdr) sodium channel mutations which render the action of insecticides ineffectual, even when co-administered withpiperonyl butoxide. Characterization of the different forms of resistance among mosquitoes has become a top priority in groups studyingtropical medicine due to the high mortality of those who reside in endemic areas.[2]
Two mutations, the valine to leucine mutation (V419L) and the leucine to isoleucine mutation (L925I) in voltage-gated sodium channel α-subunit gene, have been identified as responsible for knockdown resistance to deltamethrin inbed bugs. One study found that 88% of bed bug populations in the US had at least one of the two mutations, if not both, meaning that deltamethrin resistance amongbed bugs is currently making this insecticide obsolete.[3]
Deltamethrin belongs to a group of pesticides called synthetic pyrethroids. This pesticide is toxic to aquatic life, particularly fish, and therefore must be used with extreme caution around water.
Although generally considered safe to use, it isneurotoxic to humans in high doses. Pyrethroids like Deltamethrin can also be anallergen that provokesasthma in some people.[4]
Deltamethrin temporarily attacks the nervous system of any animal with which it comes into contact. Skin contact can lead to tingling or reddening of the skin local to the application. If taken in through the eyes or mouth, the most common symptom is facialparaesthesia, which can feel like many different abnormal sensations, including burning, partial numbness, "pins and needles", skin crawling, etc. There is one case report describing chronic intoxication from pyrethroid insecticides leading to a syndrome clinically similar tomotor neuron disease.[5] There are noantidotes, and treatment must be symptomatic, as approved by a physician. Over time, deltamethrin ismetabolized, with a rapid loss of toxicity, and passed from the body. Apoison control center should be contacted in the event of an accidental poisoning.
Deltamethrin is able to pass from a woman's skin through her blood and into her breast milk, although breastfeeding remains safe under prevailing conditions. In South Africa, residues of deltamethrin were found inbreast milk, together withDDT, in an area that used DDT treatment for malaria control, as well as pyrethroids insmall-scale agriculture.[6]
A 2015 study conducted inBrittany, France, found a negative correlation between deltamethrin exposure (measured through the presence of a metabolite in urine) and cognitive scores in infants.[7]
Cases of toxicity have been observed in cattle, following use of agricultural deltamethrin preparation in external application fortick control.[citation needed]
