| Anopheles arabiensis | |
|---|---|
 | |
Scientific classification  | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Arthropoda |
| Class: | Insecta |
| Order: | Diptera |
| Family: | Culicidae |
| Genus: | Anopheles |
| Subgenus: | Cellia |
| Species: | A. arabiensis |
| Binomial name | |
| Anopheles arabiensis Patton, 1905 | |
Anopheles arabiensis [1] is a zoophilic species of mosquito and a vector of disease endemic to Africa.
Polytene chromosomes have a high degree of gene polymorphism due to paracentric inversions. This is also unusually high for the genus. (See the chapter by Kitzmiller 1976.) [2] There is a well studied adaptive inversion. Kirkpatrick and Barrett 2015 and Sharakhov et al. 2006 find an inversion providing A. arabiensis with some of its adaptation to arid environments. They also find this inversion has been introgressed across more widely in the genus, providing similar adaptive benefit. [3]
Not thought to naturally serve as a host of Wolbachia [4] until Baldini et al. 2018 showed to the contrary. [5] [6]
Hosts include Bos taurus . [7] A. arabiensis is especially known as a zoophilic haematophage. [8]
Not a vector of Plasmodium berghei . [9]
The distribution is Afrotropical. There was a brief invasion into Brazil in 1930 but this was quickly eradicated. (Note that this was long misidentified as an invasion by A. gambiae . Only with genetic tools and a great deal of time did Parmekalis et al. 2008 find it to really have been A. arabiensis.) [10] The investigations regarding the ecology of A. arabiensis by Gwitira et al. 2018, Ageep et al. 2009 and Fuller et al. 2012a help to model the distribution of various avian malaria pathogens. [11]
Locally A. arabiensis' is especially known as an exophage and exophile. [8] Its movements through the local ecology are not sufficiently studied – Debebe et al. 2018 is one of the few investigations in this question. [12]
Cyhalothrins (including λ-cyhalothrin) and DDT are commonly used. Mnzava et al. 1995 finds differential repellent effects between λc and DDT in the protection of cattle, partly due to DDT's excitorepellency. (Some of the difference is also due to differences in keeping cattle outside or inside. A. arabiensis' proclivity to enter or not enter, and exit or not exit barns treated with λc or DDT makes a difference.) [7]
Sterile insect technique shows promise in A. arabiensis. Irradiation in SIT is not simple however and dosage is a touchy variable. Sterile males are also injured more generally by the process and thus are less competitive. Helinski and Knols 2008 provide dosage information from their experiments with A. arabiensis which is needed to perform SIT successfully. [13]
This process requires separation of the sexes which historically has been done manually, greatly limiting throughput. Mashatola et al. 2018 [14] reviews progress in automation, selective insecticide feeding, and genetic sexing strains. [13]
SIT may also be achieved by genetic modification, disabling the reproductive process. Catteruccia et al. 2005 produced such an A. arabiensis strain and demonstrates more generally that genetic SIT is tractable in this species. [4]
As of 2015 [update] it has only recently been found that adult mosquitoes are vulnerable to entomopathogenic fungi. This has provoked interest in studying this kind of control, especially Kikankie et al. 2010's success with Beauveria bassiana . [15]
Understanding of A. arabiensis' movements through the landscape will need to improve to aid control efforts. Debebe et al. 2018 is one of very few contributions to this area. [12]
Some resistant A. arabiensis populations are known. Ismail et al. 2018 find a high degree of pyrethroid resistance in Sudan and Opondo et al. 2019 find the same in The Gambia. [16] Hargreaves et al. 2003 finds DDT resistance in South Africa severe enough to impact efficacy. [17] Agricultural runoff encourages DDT resistance: A. arabiensis larvae grow in waste water pools nearby and are encouraged toward resistance by the insecticides applied to the crops. Oliver and Brooke 2013 find this to be especially problematic adjacent to maize cultivation. [18]
Dichlorodiphenyltrichloroethane, commonly known as DDT, is a colorless, tasteless, and almost odorless crystalline chemical compound, an organochloride. Originally developed as an insecticide, it became infamous for its environmental impacts. DDT was first synthesized in 1874 by the Austrian chemist Othmar Zeidler. DDT's insecticidal action was discovered by the Swiss chemist Paul Hermann Müller in 1939. DDT was used in the second half of World War II to limit the spread of the insect-borne diseases malaria and typhus among civilians and troops. Müller was awarded the Nobel Prize in Physiology or Medicine in 1948 "for his discovery of the high efficiency of DDT as a contact poison against several arthropods". The WHO's anti-malaria campaign of the 1950s and 1960s relied heavily on DDT and the results were promising, though there was a resurgence in developing countries afterwards.
Malaria is a mosquito-borne infectious disease that affects vertebrates. Human malaria causes symptoms that typically include fever, fatigue, vomiting, and headaches. In severe cases, it can cause jaundice, seizures, coma, or death. Symptoms usually begin 10 to 15 days after being bitten by an infected Anopheles mosquito. If not properly treated, people may have recurrences of the disease months later. In those who have recently survived an infection, reinfection usually causes milder symptoms. This partial resistance disappears over months to years if the person has no continuing exposure to malaria.
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Pesticide resistance describes the decreased susceptibility of a pest population to a pesticide that was previously effective at controlling the pest. Pest species evolve pesticide resistance via natural selection: the most resistant specimens survive and pass on their acquired heritable changes traits to their offspring. If a pest has resistance then that will reduce the pesticide's efficacy – efficacy and resistance are inversely related.
Anopheles is a genus of mosquito first described by J. W. Meigen in 1818, and are known as nail mosquitoes and marsh mosquitoes. Many such mosquitoes are vectors of the parasite Plasmodium, a genus of protozoans that cause malaria in birds, reptiles, and mammals, including humans. The Anopheles gambiae mosquito is the best-known species of marsh mosquito that transmits the Plasmodium falciparum, which is a malarial parasite deadly to human beings; no other mosquito genus is a vector of human malaria.
A pyrethroid is an organic compound similar to the natural pyrethrins, which are produced by the flowers of pyrethrums. Pyrethroids are used as commercial and household insecticides.
Aedes aegypti, the yellow fever mosquito, is a mosquito that can spread dengue fever, chikungunya, Zika fever, Mayaro and yellow fever viruses, and other disease agents. The mosquito can be recognized by black and white markings on its legs and a marking in the form of a lyre on the upper surface of its thorax. This mosquito originated in Africa, but is now found in tropical, subtropical and temperate regions throughout the world.
A mosquito net is a type of meshed curtain that is circumferentially draped over a bed or a sleeping area, to offer the sleeper barrier protection against bites and stings from mosquitos, flies, and other pest insects, and thus against the diseases they may carry. Examples of such preventable insect-borne diseases include malaria, dengue fever, yellow fever, zika virus, Chagas disease and various forms of encephalitis, including the West Nile virus.
Mosquito control manages the population of mosquitoes to reduce their damage to human health, economies, and enjoyment. Mosquito control is a vital public-health practice throughout the world and especially in the tropics because mosquitoes spread many diseases, such as malaria and the Zika virus.
Deltamethrin is a pyrethroid ester insecticide. Deltamethrin plays a key role in controlling malaria vectors, and is used in the manufacture of long-lasting insecticidal mosquito nets; however, resistance of mosquitos and bed bugs to deltamethrin has seen a widespread increase.
The Anopheles gambiae complex consists of at least seven morphologically indistinguishable species of mosquitoes in the genus Anopheles. The complex was recognised in the 1960s and includes the most important vectors of malaria in sub-Saharan Africa, particularly of the most dangerous malaria parasite, Plasmodium falciparum. It is one of the most efficient malaria vectors known. The An. gambiae mosquito additionally transmits Wuchereria bancrofti which causes lymphatic filariasis, a symptom of which is elephantiasis.
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Indoor residual spraying or IRS is the process of spraying the inside of dwellings with an insecticide to kill mosquitoes that spread malaria. A dilute solution of insecticide is sprayed on the inside walls of certain types of dwellings—those with walls made from porous materials such as mud or wood but not plaster as in city dwellings. Mosquitoes are killed or repelled by the spray, preventing the transmission of the disease. In 2008, 44 countries employed IRS as a malaria control strategy. Several pesticides have historically been used for IRS, the first and most well-known being DDT.
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