Anopheles gambiae

{{Short description|Species complex of mosquitos}} {{Italic title}} {{Automatic taxobox | image = AnophelesGambiaemosquito.jpg | subdivision_ranks = Species | subdivision = * ''A. arabiensis'' * ''A. bwambae'' * ''A. melas'' * ''A. merus'' * ''A. quadriannulatus'' * ''A. gambiae'' sensu stricto * ''A. coluzzii'' * ''A. amharicus'' | taxon = Anopheles gambiae species complex | authority = Giles 1902<ref>{{Cite book |last=Giles |first=G. M. |year=1902 |title=A handbook of the gnats or mosquitoes giving the anatomy and life history of the Culicidae together with descriptions of all species noticed up to the present date |publisher=John Bale, Sons & Danielsson |location=London, United Kingdom}}</ref> }} [[File:Structural organization of the heart of the mosquito Anopheles gambiae - image.ppat.v08.i11.g001.png|thumb|The tube-like heart (green) extends along the body, interlinked with the diamond-shaped alary muscles (also green) and surrounded by pericardial cells (red). Blue depicts cell nuclei.]]

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''.<ref>{{cite web|url=http://www.wrbu.org/SpeciesPages_ANO/ANO_A-hab/ANara_hab.html |publisher=Walter Reed Army Institute of Research |title=''Anopheles gambiae'' complex |archive-url=https://web.archive.org/web/20070929181159/http://www.wrbu.org/SpeciesPages_ANO/ANO_A-hab/ANara_hab.html |archive-date=2007-09-29 }}</ref> 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.<ref>{{Cite web|url=https://www.who.int/news-room/fact-sheets/detail/lymphatic-filariasis|title=Lymphatic filariasis|website=www.who.int|language=en|access-date=2020-04-10}}</ref>

==Discovery and elements== The ''Anopheles gambiae'' complex or ''Anopheles gambiae'' sensu lato was recognized as a species complex only in the 1960s. The ''A. gambiae'' complex consists of:<ref name=WRBU>{{cite web |website=The Walter Reed Biosystematics Unit (WRBU) |title=''Anopheles gambiae'' Giles, 1902 |url=https://wrbu.si.edu/vectorspecies/mosquitoes/gambiae |date=2021 |access-date=2025-03-27 }}</ref> * ''Anopheles arabiensis'' Patton, 1905 * ''Anopheles bwambae'' White, 1985 * ''Anopheles melas'' Theobald, 1903 * ''Anopheles merus'' Dönitz, 1902 * ''Anopheles quadriannulatus'' (Theobald, 1911)<ref>{{cite journal |doi=10.1073/pnas.91.15.6885 |vauthors=Besansky NJ, Powell JR, Caccone A, Hamm DM, Scott JA, Collins FH |title=Molecular phylogeny of the ''Anopheles gambiae'' complex suggests genetic introgression between principal malaria vectors |journal=Proceedings of the National Academy of Sciences |volume=91 |issue=15 |pages=6885–8 |date=July 1994 |pmid=8041714 |pmc=44302 |bibcode=1994PNAS...91.6885B |doi-access=free }}</ref><ref>{{cite journal |vauthors=Wilkins EE, Howell PI, Benedict MQ |title=IMP PCR primers detect single nucleotide polymorphisms for ''Anopheles gambiae'' species identification, Mopti and Savanna rDNA types, and resistance to dieldrin in ''Anopheles arabiensis'' |journal=Malaria Journal |volume=5 |issue= 1|article-number=125 |year=2006 |pmid=17177993 |pmc=1769388 |doi=10.1186/1475-2875-5-125 |doi-access=free }}</ref> * ''Anopheles gambiae'' Giles, 1902 sensu stricto (s.s.)<ref name=Yakob2011>{{Cite journal|doi=10.1098/rsbl.2011.0453|title=Epidemiological consequences of a newly discovered cryptic subgroup of ''Anopheles gambiae''|year=2011|last1=Yakob|first1=Laith|journal=Biology Letters|volume=7|issue=6|pages=947–949|pmid=21693489|pmc=3210673}}</ref> * ''{{visible anchor|Anopheles coluzzii}}'' Coetzee & Wilkerson in Coetzee et al., 2013 * ''Anopheles amharicus'' Hunt, Wilkerson & Coetzee in Coetzee et al., 2013

The individual species of the complex are morphologically difficult to distinguish from each other, although it is possible for larvae and adult females. The species exhibit different behavioural traits. For example, ''Anopheles quadriannulatus'' is both a saltwater and mineralwater species. ''A. melas'' and ''A. merus'' are saltwater species, while the remainder are freshwater species.<ref name=white>{{cite journal | title=''Anopheles gambiae'' complex and disease transmission in Africa | author=G.B. White | journal= Transactions of the Royal Society of Tropical Medicine and Hygiene| year=1974 | volume=68 | issue=4 | pages=278–298 | doi=10.1016/0035-9203(74)90035-2| pmid=4420769 }}</ref> ''Anopheles quadriannulatus'' generally takes its blood meal from animals (zoophilic), whereas ''Anopheles gambiae'' sensu stricto generally feeds on humans, i.e. is considered anthropophilic.{{citation needed|date=July 2016}} Identification to the individual species level using the molecular methods of Scott ''et al.'' (1993)<ref>{{cite journal |author1=C. Fanello |author2=F. Santolamazza |author3=A. Della Torre |title=Simultaneous identification of species and molecular forms of the ''Anopheles gambiae'' complex by PCR-RFLP |journal=Medical and Veterinary Entomology |volume=16 |issue=4 |pages=461–4 |year=2002 |doi=10.1046/j.1365-2915.2002.00393.x |pmid=12510902|s2cid=28983355 }}</ref> can have important implications in subsequent control measures.

== ''Anopheles gambiae'' in the strict sense == ''An. gambiae sensu stricto'' (s.s.) has been discovered to be currently in a state of diverging into two different species—the Mopti (M) and Savannah (S) strains—though as of 2007, the two strains are still considered to be a single species.<ref name="Genoscope" /><ref name="Lawniczak" />

A mechanism of species recognition using the sound emitted by the wings and identified by Johnston's organ was proposed in 2010,<ref name="Pennetier2009">{{cite journal |last1=Pennetier |first1=Cédric |last2=Warren |first2=Ben |last3=Dabiré |first3=K. Roch |last4=Russell |first4=Ian J. |last5=Gibson |first5=Gabriella |author-link5=Gabriella Gibson |year=2010 |title="Singing on the Wing" as a Mechanism for Species Recognition in the Malarial Mosquito ''Anopheles gambiae'' |url=http://hal.archives-ouvertes.fr/hal-03249004 |journal=Current Biology |volume=20 |issue=2 |pages=131–136 |doi=10.1016/j.cub.2009.11.040 |pmid=20045329 |s2cid=15185976 |doi-access=free|bibcode=2010CBio...20..131P }}</ref> however this mechanism has never been confirmed since, and the overall mechanism theory through "harmonic convergence" has been challenged.<ref>{{Cite journal |last1=Somers |first1=Jason |last2=Georgiades |first2=Marcos |last3=Su |first3=Matthew P. |last4=Bagi |first4=Judit |last5=Andrés |first5=Marta |last6=Alampounti |first6=Alexandros |last7=Mills |first7=Gordon |last8=Ntabaliba |first8=Watson |last9=Moore |first9=Sarah J. |last10=Spaccapelo |first10=Roberta |last11=Albert |first11=Joerg T. |date=2022-01-14 |title=Hitting the right note at the right time: Circadian control of audibility in Anopheles mosquito mating swarms is mediated by flight tones |journal=Science Advances |language=en |volume=8 |issue=2 |article-number=eabl4844 |doi=10.1126/sciadv.abl4844 |issn=2375-2548 |pmc=8754303 |pmid=35020428|bibcode=2022SciA....8.4844S }}</ref><ref>{{Citation |last1=Feugère |first1=L. |title=Chapter 26: The role of hearing in mosquito behaviour |date=2022-12-18 |work=Sensory ecology of disease vectors |pages=683–708 |editor-last=Ignell |editor-first=R. |url=https://brill.com/view/book/9789086869329/BP000027.xml |access-date=2024-05-30 |publisher=Brill {{!}} Wageningen Academic |doi=10.3920/978-90-8686-932-9_26 |isbn=978-90-8686-380-8 |last2=Simões |first2=P.M.V. |last3=Russell |first3=I.J. |last4=Gibson |first4=G. |editor2-last=Lazzari |editor2-first=C.R. |editor3-last=Lorenzo |editor3-first=M.G. |editor4-last=Hill |editor4-first=S.R.}}</ref>

== Genome == ''An. gambiae'' s.s. genomes have been sequenced three times, once for the M strain, once for the S strain, and once for a hybrid strain.<ref name="Genoscope">{{cite web |url=http://www.cns.fr/externe/English/Projets/Projet_AK/organisme_AK.html |title=''Anopheles gambiae'': First genome of a vector for a parasitic disease |publisher=Genoscope |archive-url=https://web.archive.org/web/20110807095743/http://www.genoscope.cns.fr/spip/Anopheles-gambiae-vector-for-a.html |archive-date=2011-08-07}}</ref><ref name="Lawniczak">{{cite journal|author=Lawniczak, M. K.|title=Widespread divergence between incipient ''Anopheles gambiae'' species revealed by whole genome sequences|journal=Science |date=Oct 22, 2010|volume=330|issue=6003|pages=512–4|pmid=20966253|doi=10.1126/science.1195755|pmc=3674514|bibcode=2010Sci...330..512L|display-authors=etal}}</ref> Currently, ~90 miRNA have been predicted in the literature (38 miRNA officially listed in miRBase) for ''An. gambiae'' s.s. based upon conserved sequences to miRNA found in ''Drosophila''.{{citation needed|date=February 2022}} Holt ''et al.'', 2002 and Neafsey ''et al.'', 2016 find transposable elements to be ~13% of the genome, similar to ''Drosophila melanogaster'' (also in Diptera).<ref name="Gilbert-et-al-2021">{{cite journal | last1=Gilbert | first1=Clément | last2=Peccoud | first2=Jean | last3=Cordaux | first3=Richard | title=Transposable Elements and the Evolution of Insects | journal=Annual Review of Entomology | volume=66 | issue=1 | date=2021-01-07 | issn=0066-4170 | doi=10.1146/annurev-ento-070720-074650 | pages=355–372| pmid=32931312 | s2cid=221747772 | url=https://hal.archives-ouvertes.fr/hal-03376520/file/Gilbert_et_al_30Jan20_text%2BFig.pdf }}</ref> However they find the proportion of TE types to be very different from ''D. melanogaster'' with approximately the same composition of long terminal repeat retrotransposons, non-long terminal repeat retrotransposons and DNA transposons.<ref name="Gilbert-et-al-2021" /> These proportions are believed to be representative of the genus.<ref name="Gilbert-et-al-2021" />

The genetics and genomics of sex chromosomes have been discovered and studied by Windbichler ''et al.'', 2007 and Galizi ''et al.'', 2014 (a ''Physarum polycephalum'' homing endonuclease which destroys X chromosomes), Windbichler ''et al.'', 2008 and Hammond ''et al.'', 2016 (methods to reduce the female population), Windbichler ''et al.'', 2011 (trans from yeast), Bernardini ''et al.'', 2014 (a method to increase the male population), Kyrou ''et al.'', 2018 (a female necessary exon and a homing endonuclease to drive it), Taxiarchi ''et al.'', 2019 (sex chromosome dynamics in general) and Simoni ''et al.'', 2020 (an X chromosome destroying site specific nuclease).<ref name="Hay-et-al-2021">{{cite journal | last1=Hay | first1=Bruce A. | last2=Oberhofer | first2=Georg | last3=Guo | first3=Ming | title=Engineering the Composition and Fate of Wild Populations with Gene Drive | journal=Annual Review of Entomology | volume=66 | issue=1 | date=2021-01-07 | issn=0066-4170 | doi=10.1146/annurev-ento-020117-043154 | pages=407–434| pmid=33035437 | s2cid=222257628 | doi-access=free }}</ref> See {{section link||Gene drive}} below for their applications.

''An. gambiae'' has a high degree of polymorphism. This is especially true in the cytochrome P450s, Wilding ''et al.'', 2009 finding 1 single nucleotide polymorphism (SNP)/26 base pairs. This species has the highest amount of polymorphism in the CYPs of any insect known, much tending to be found in "scaffolds" that are found only in particular subpopulations. These are termed "dual haplotype regions" by Holt ''et al.'', 2002 who sequenced the {{visible anchor|PEST}} strain.<ref name="Gilbert-2012">{{cite book | editor-last=Gilbert | editor-first=Lawrence I. | title=Insect molecular biology and biochemistry | publisher=Academic Press | publication-place=Amsterdam Boston | year=2012 | isbn=978-0-12-384747-8 | oclc=742299021 | pages=x+563}}</ref>{{rp|241}}

In common with many chromosomes, ''An. gambiae'' codes for spindle and kinetochore-associated proteins. Hanisch ''et al.'', 2006 locate ''AgSka1'', the spindle and kinetochore-associated protein 1 gene, at EAL39257.<ref name="Cheeseman-Desai-2008">{{cite journal | last1=Cheeseman | first1=Iain M. | last2=Desai | first2=Arshad | title=Molecular architecture of the kinetochore–microtubule interface | journal=Nature Reviews Molecular Cell Biology | publisher=Nature Portfolio | volume=9 | issue=1 | year=2008 | issn=1471-0072 | doi=10.1038/nrm2310 | pages=33–46| pmid=18097444 | s2cid=34121605 }}</ref>

The entire Culicidae family may or may not conserve epigenetic mechanisms {{endash}} {{as of|2012|lc=yes}} this remains unresolved.<ref name="Severson-Behura-2012">{{cite journal | last1=Severson | first1=David W. | last2=Behura | first2=Susanta K. | title=Mosquito Genomics: Progress and Challenges | journal=Annual Review of Entomology | publisher=Annual Reviews | volume=57 | issue=1 | date=2012-01-07 | issn=0066-4170 | doi=10.1146/annurev-ento-120710-100651 | pages=143–166| pmid=21942845 }}</ref> Toward answering this question, Marhold ''et al.'', 2004 compare their own previous work in ''Drosophila melanogaster'' against new sequences of ''D. pseudoobscura'' and ''An. gambiae''.<ref name="Severson-Behura-2012" /> They find all three do share the DNA methylation enzyme DNMT2 (''DmDNMT2'', ''DpDNMT2'', and ''{{visible anchor|AgDNMT2}}'').<ref name="Severson-Behura-2012" /> This suggests all Diptera may conserve an epigenetic system employing Dnmt2.<ref name="Severson-Behura-2012" />

==Hosts==

Hosts include cattle, goats, sheep and wild boar.<ref name="CABIISC">{{cite web | title=''Anopheles gambiae'' | website=Invasive Species Compendium | publisher=CABI | date=2019-11-24 | url=http://www.cabi.org/isc/datasheet/93919 | access-date=2022-01-26}}</ref>

==Parasites==

Parasites include ''Plasmodium berghei'' (for which it also serves as a vector),<ref name="Alout-et-al-2017">{{cite journal | last1=Alout | first1=Haoues | last2=Labbé | first2=Pierrick | last3=Chandre | first3=Fabrice | last4=Cohuet | first4=Anna | title=Malaria Vector Control Still Matters despite Insecticide Resistance | journal=Trends in Parasitology | volume=33 | issue=8 | year=2017 | issn=1471-4922 | doi=10.1016/j.pt.2017.04.006 | pages=610–618 | s2cid=32524464 | pmid=28499699}}</ref><ref name="Minetti-et-al-2020">{{cite journal | last1=Minetti | first1=Corrado | last2=Ingham | first2=Victoria A | last3=Ranson | first3=Hilary | title=Effects of insecticide resistance and exposure on ''Plasmodium'' development in ''Anopheles'' mosquitoes | journal=Current Opinion in Insect Science | volume=39 | year=2020 | issn=2214-5745 | doi=10.1016/j.cois.2019.12.001 | pages=42–49| pmid=32109860 | bibcode=2020COIS...39...42M | s2cid=211563675 | url=https://archive.lstmed.ac.uk/13640/1/Effects%20of%20insecticide%20and%20exposure%20on%20Plasmodium%20in%20Anopheles%20mosquitoes%20-%20HRanson.pdf }}</ref><ref name="Caragata-et-al-2020">{{cite journal | last1=Caragata | first1=E.P. | last2=Dong | first2=S. | last3=Dong | first3=Y. | last4=Simões | first4=M.L. | last5=Tikhe | first5=C.V. | last6=Dimopoulos | first6=G. | title=Prospects and Pitfalls: Next-Generation Tools to Control Mosquito-Transmitted Disease | journal=Annual Review of Microbiology | publisher=Annual Reviews | volume=74 | issue=1 | date=2020-09-08 | issn=0066-4227 | doi=10.1146/annurev-micro-011320-025557 | pages=455–475| pmid=32905752 | s2cid=221625690 | doi-access=free }}</ref> and the bioinsecticides/entomopathogenic fungi ''Metarhizium robertsii''<ref name="Alout-et-al-2017" /> and ''Beauveria bassiana''.<ref name="Alout-et-al-2017" /> All three of these parasites combine with insecticides to reduce fitness {{endash}} see {{section link||Insecticides}} below.<ref name="Alout-et-al-2017" /> CRISPR/Cas9 and U6-gRNA are increasingly ({{as of|2020|lc=yes}}) being used together for knockout experiments in mosquitoes.<ref name="Caragata-et-al-2020" /> Dong ''et al.'', 2018 develops and presents a new U6-gRNA+Cas9 technique in ''An. gambiae'', and utilizes it to knock out fibrinogen related protein 1 (FREP1), thereby severely reducing infection of the mosquito by ''P. berghei'' and ''P. falciparum''.<ref name="Caragata-et-al-2020" /> However this also demonstrates the centrality of FREP1 to the insect's success, impairing all measured activities across all life stages.<ref name="Caragata-et-al-2020" /> Yang ''et al.'', 2020 uses the Dong method to do the same with ''mosGILT'', also severely reducing ''Plasmodium'' infection of the mosquito but ''also'' finding a vital life process is impaired, in ''mosGILT''{{'}}s case ovary development.<ref name="Caragata-et-al-2020" />

==Control==

===Insecticides===

Parasites/bioinsecticides and chemical insecticides synergistically reduce fitness. Saddler ''et al.'', 2015 finds even ''An. gambiae'' with knockdown resistance (''kdr'') are more susceptible to DDT if they are first infected with ''Plasmodium berghei''<ref name="Alout-et-al-2017" /><ref name="Minetti-et-al-2020" /> and Farenhorst ''et al.'', 2009 the same for ''Metarhizium robertsii'' or ''Beauveria bassiana''.<ref name="Alout-et-al-2017" /> This is probably due to an effect found by Félix ''et al.'', 2010 and Stevenson ''et al.'', 2011: ''An. gambiae'' alters various activities {{endash}} especially CYP6M2 {{endash}} in response to ''P. berghei'' invasion. CYP6M2 is known to somehow produce pyrethroid resistance, and pyrethroids and DDT share a mechanism of action.<ref name="Minetti-et-al-2020" />

=== Gene drive === Research relevant to the development of gene drive controls of ''An. gambiae'' have been performed by Windbichler ''et al.'', 2007, Windbichler ''et al.'', 2008, Windbichler ''et al.'', 2011, Bernardini ''et al.'', 2014, Galizi ''et al.'', 2014, Hammond ''et al.'', 2016, Kyrou ''et al.'', 2018, Taxiarchi ''et al.'', 2019 and Simoni ''et al.'', 2020.<ref name="Hay-et-al-2021" /> For specific genes involved see {{section link||Genome}} above. These can all be used in pest control because they induce infertility.<ref name="Hay-et-al-2021" />

==Fecundity==

Fecundity of ''An. gambiae'' depends on the detoxification of reactive oxygen species (ROS) by catalase.<ref name="pmid17284604">{{cite journal |vauthors=DeJong RJ, Miller LM, Molina-Cruz A, Gupta L, Kumar S, Barillas-Mury C |title=Reactive oxygen species detoxification by catalase is a major determinant of fecundity in the mosquito ''Anopheles gambiae'' |journal=Proceedings of the National Academy of Sciences|volume=104 |issue=7 |pages=2121–6 |date=February 2007 |pmid=17284604 |pmc=1892935 |doi=10.1073/pnas.0608407104 |bibcode=2007PNAS..104.2121D |doi-access=free }}</ref> Reduction in catalase activity significantly reduces reproductive output of female mosquitoes, indicating that catalase plays a central role in protecting oocytes and early embryos from ROS damage.<ref name="pmid17284604" />

== Historical note ==

''An. gambiae'' invaded northeastern Brazil in 1930, which led to a malaria epidemic in 1938/1939.<ref name="Killeen2003">{{cite journal |doi=10.1016/S1473-3099(03)00776-X |author=Killeen GF |title=Following in Soper's footsteps: northeast Brazil 63 years after eradication of ''Anopheles gambiae'' |journal=The Lancet Infectious Diseases |volume=3 |issue=10 |pages=663–6 |date=October 2003 |pmid=14522266 }}</ref> The Brazilian government assisted by the Rockefeller Foundation in a programme spearheaded by Fred Soper eradicated these mosquitoes from this area. This effort was modeled on the earlier success in eradication of ''Aedes aegypti'' as part of the yellow fever control program. The exact species involved in this epidemic has been identified as ''An. arabiensis''.<ref name= parma>{{cite journal |vauthors=Parmakelis A, Russello MA, Caccone A |title=Historical analysis of a near disaster: ''Anopheles gambiae'' in Brazil |journal=The American Journal of Tropical Medicine and Hygiene |volume=78 |issue=1 |pages=176–8 |date=January 2008 |pmid=18187802 |doi= 10.4269/ajtmh.2008.78.176|url=http://www.ajtmh.org/cgi/pmidlookup?view=long&pmid=18187802|display-authors=etal|doi-access=free |url-access=subscription }}</ref>

== Peptide hormones ==

Kaufmann and Brown 2008 find the ''An. gambiae'' adipokinetic hormone (AKH) mobilizes carbohydrates but not lipids. Meanwhile AKH/Corazonin Peptide (ACP) does not mobilize (or inhibit mobilization) of either. Mugumbate ''et al.'', 2013 provides in solution and membrane bound structures from a nuclear magnetic resonance investigation.<ref name="Strand-et-al-2016">{{cite book | last1=Strand | first1=M.R. | last2=Brown | first2=M.R. | last3=Vogel | first3=K.J. | title=Advances in Insect Physiology | chapter=Mosquito Peptide Hormones | publisher=Elsevier | year=2016 | volume=51 | issn=0065-2806 | doi=10.1016/bs.aiip.2016.05.003 | pages=145–188 | s2cid=58546659 | pmid=30662099 | pmc=6338476| isbn=978-0-12-802457-7 }}</ref>

== References == {{Reflist|2}}

== External links == {{Scholia|topic}} * {{cite web |url=https://www.vectorbase.org/organisms/anopheles-gambiae |publisher=VectorBase |title=''Anopheles gambiae'' |access-date=2013-07-12 |archive-date=2019-01-27 |archive-url=https://web.archive.org/web/20190127205740/https://www.vectorbase.org/organisms/anopheles-gambiae }} * {{UCSC genomes|anoGam1}} * [http://www.diark.org/diark/species_list?query=Anopheles_gambiae DiArk]

gambiae Category:Insect vectors of human pathogens Category:Animal models Category:Insects described in 1902