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Le Infezioni in Medicina Jun 2016Malaria, the most common parasitic disease in the world, is transmitted to the human host by mosquitoes of the genus Anopheles. The transmission of malaria requires the... (Review)
Review
Malaria, the most common parasitic disease in the world, is transmitted to the human host by mosquitoes of the genus Anopheles. The transmission of malaria requires the interaction between the host, the vector and the parasite.The four species of parasites responsible for human malaria are Plasmodium falciparum, Plasmodium ovale, Plasmodium malariae and Plasmodium vivax. Occasionally humans can be infected by several simian species, like Plasmodium knowlesi, recognised as a major cause of human malaria in South-East Asia since 2004. While P. falciparum is responsible for most malaria cases, about 8% of estimated cases globally are caused by P. vivax. The different Plasmodia are not uniformly distributed although there are areas of species overlap. The life cycle of all species of human malaria parasites is characterised by an exogenous sexual phase in which multiplication occurs in several species of Anopheles mosquitoes, and an endogenous asexual phase in the vertebrate host. The time span required for mature oocyst development in the salivary glands is quite variable (7-30 days), characteristic of each species and influenced by ambient temperature. The vector Anopheles includes 465 formally recognised species. Approximately 70 of these species have the capacity to transmit Plasmodium spp. to humans and 41 are considered as dominant vector capable of transmitting malaria. The intensity of transmission is dependent on the vectorial capacity and competence of local mosquitoes. An efficient system for malaria transmission needs strong interaction between humans, the ecosystem and infected vectors. Global warming induced by human activities has increased the risk of vector-borne diseases such as malaria. Recent decades have witnessed changes in the ecosystem and climate without precedent in human history although the emphasis in the role of temperature on the epidemiology of malaria has given way to predisposing conditions such as ecosystem changes, political instability and health policies that have reduced the funds for vector control, combined with the presence of migratory flows from endemic countries.
Topics: Animals; Anopheles; Climate; Climate Change; Disease Reservoirs; Endemic Diseases; Female; Global Health; Hominidae; Humans; Insect Vectors; Life Cycle Stages; Malaria; Plasmodium; Population Dynamics; Primate Diseases; Species Specificity; Urbanization
PubMed: 27367318
DOI: No ID Found -
Brain Research Bulletin Feb 2019Malaria remains of significant public health concern under the tropics, causing millions of deaths annually. The disease is caused by protozoans of the Plasmodium genus,... (Review)
Review
Malaria remains of significant public health concern under the tropics, causing millions of deaths annually. The disease is caused by protozoans of the Plasmodium genus, of which harbors several distinct species. Human infection occurs during the blood meal of an infected female mosquito belonging to the Anopheles genus. It is estimated that around 1% of children infected with Plasmodium falciparum develops a more severe form of malaria, which may eventually lead to cerebral complications including cerebral malaria (CM). CM can be positively diagnosed in patients unable to localize a painful stimulus, with peripheral asexual P. falciparum parasitemia and no other identifiable causes of an encephalopathy. Unarousable comas along with the presence of asexual forms of the parasite on a peripheral blood smear are hallmarks of the disease. While the molecular mechanisms underlying the pathogenesis of CM have yet be fully elucidated, the pathology in itself indicates a clear disease of the vascular endothelium. It is characterized by parasite sequestration, inflammatory cytokine production and vascular leakage, eventually resulting in brain hypoxia. The condition requires systemic health management consisting of focused nursing practices, supportive care, and anti-malarial drugs. The continued understanding of pathogenic mechanisms leading to the onset of CM is fundamental and key for the expansion and development of appropriate neuroprotective interventions. Future research perspectives may also include the development of field-based and rapid diagnostic tests for CM, understanding of host-pathogen interactions to advance development of prevention tools and therapies, and antimalarial drug trials.
Topics: Africa; Animals; Anopheles; Antimalarials; Humans; Malaria, Cerebral; Plasmodium; Plasmodium falciparum
PubMed: 30658131
DOI: 10.1016/j.brainresbull.2019.01.010 -
Parasites & Vectors Sep 2021Despite the medical importance of mosquitoes of the genus Anopheles in the transmission of malaria and other human diseases, its phylogenetic relationships are not...
BACKGROUND
Despite the medical importance of mosquitoes of the genus Anopheles in the transmission of malaria and other human diseases, its phylogenetic relationships are not settled, and the characteristics of mitochondrial genome (mitogenome) are not thoroughly understood.
METHODS
The present study sequenced and analyzed the complete mitogenomes of An. peditaeniatus and An. nitidus, investigated genome characteristics, and inferred the phylogenetic relationships of 76 Anopheles spp.
RESULTS
The complete mitogenomes of An. peditaeniatus and An. nitidus are 15,416 and 15,418 bp long, respectively, and both include 13 PCGs, 22 tRNAs, two tRNAs and one control region (CR). Mitogenomes of Anopheles spp. are similar to those of other insects in general characteristics; however, the trnR and trnA have been reversed to "trnR-trnA," as has been reported in other mosquito genera. Genome variations mainly occur in CR length (493-886 bp) with six repeat unit types identified for the first time that demonstrate an evolutionary signal. The subgenera Lophopodomyia, Stethomyia, Kerteszia, Nyssorhynchus, Anopheles and Cellia are inferred to be monophyletic, and the phylogenetic analyses support a new phylogenetic relationship among the six subgenera investigated, in that subgenus Lophopodomyia is the sister to all other five subgenera, and the remaining five subgenera are divided into two clades, one of which is a sister-taxon subgenera Stethomyia + Kerteszia, and the other consists of subgenus Nyssorhynchus as the sister to a sister-group subgenera Anopheles + Cellia. Four series (Neomyzomyia, Pyretophorus, Neocellia and Myzomyia) of the subgenus Cellia, and two series (Arribalzagia and Myzorhynchus) of the subgenus Anopheles were found to be monophyletic, whereas three sections (Myzorhynchella, Argyritarsis and Albimanus) and their subdivisions of the subgenus Nyssorhynchus were polyphyletic or paraphyletic.
CONCLUSIONS
The study comprehensively uncovered the characteristics of mitogenome and the phylogenetics based on mitogenomes in the genus Anopheles, and provided information for further study on the mitogenomes, phylogenetics and taxonomic revision of the genus.
Topics: Animals; Anopheles; Base Sequence; Evolution, Molecular; Genome, Mitochondrial; Phylogeny; Sequence Analysis, DNA; Species Specificity
PubMed: 34488869
DOI: 10.1186/s13071-021-04963-4 -
Journal of Medical Entomology Aug 2018The physical characteristics of a nematoceran fly that evokes the image of a mosquito of the genus Anopheles Meigen (Diptera: Culicidae) has existed since the genus was...
The physical characteristics of a nematoceran fly that evokes the image of a mosquito of the genus Anopheles Meigen (Diptera: Culicidae) has existed since the genus was defined in the early part of the twentieth century. Is that image likely to change with the recent proposal to elevate four Neotropical subgenera to generic status based on relationships generated by phylogenetic analyses of mitochondrial protein-coding genes? Reasons for retaining the traditional concept of Anopheles, with its traditionally recognized subgenera, are presented. However, as the ranking of taxa as genera or subgenera is subjective, the choice of rank of a genus-group name may be considered a subjective decision and a matter of user preference.
Topics: Animals; Anopheles; Terminology as Topic
PubMed: 30020514
DOI: 10.1093/jme/tjy108 -
Frontiers in Genetics 2014Chromosomal inversions have been repeatedly involved in local adaptation in a large number of animals and plants. The ecological and behavioral plasticity of Anopheles... (Review)
Review
Chromosomal inversions have been repeatedly involved in local adaptation in a large number of animals and plants. The ecological and behavioral plasticity of Anopheles species-human malaria vectors-is mirrored by high amounts of polymorphic inversions. The adaptive significance of chromosomal inversions has been consistently attested by strong and significant correlations between their frequencies and a number of phenotypic traits. Here, we provide an extensive literature review of the different adaptive traits associated with chromosomal inversions in the genus Anopheles. Traits having important consequences for the success of present and future vector control measures, such as insecticide resistance and behavioral changes, are discussed.
PubMed: 24904633
DOI: 10.3389/fgene.2014.00129 -
Parassitologia Sep 1999Grassi's discovery one hundred years ago brought to light the puzzle of anophelism without malaria in Europe. With the discovery of the European Anopheles maculipennis... (Review)
Review
Grassi's discovery one hundred years ago brought to light the puzzle of anophelism without malaria in Europe. With the discovery of the European Anopheles maculipennis complex the puzzle was solved but the 'species problem' has not gone away. Meaningful epidemiologic studies and effective vector control programs depend upon efficient methods for discriminating among the major vectors, lesser vectors and non-vectors of ubiquitous anopheline sibling species complexes. We now have a variety of techniques for identifying cryptic species, ranging from crossing studies through morphological, cytogenetic, allozyme and repetitive DNA-based strategies. However, cytogenetic and molecular data can also be used to infer evolutionary relationships among cryptic taxa. This approach has been crucial to understanding the biology of the vector, and may illuminate the speciation process and the human impact upon this process. Nevertheless, the analysis of cryptic taxa has proven unexpectedly complex. Studies of An. funestus and An. gambiae reveal conflicts among classes of markers and between different genomic locations. The data are consistent with a model of speciation in which gene flow may still occur in parts of the genome, and they suggest that caution should be exercised in the interpretation of results from small numbers of loci, only one type of marker, and markers located in specific genomic regions such as chromosomal inversions.
Topics: Animals; Anopheles; Genetic Variation; Humans; Phylogeny
PubMed: 10697840
DOI: No ID Found -
PloS One 2015The Anopheles genus is a member of the Culicidae family and consists of approximately 460 recognized species. The genus is composed of 7 subgenera with diverse...
The Anopheles genus is a member of the Culicidae family and consists of approximately 460 recognized species. The genus is composed of 7 subgenera with diverse geographical distributions. Despite its huge medical importance, a consensus has not been reached on the phylogenetic relationships among Anopheles subgenera. We assembled a comprehensive dataset comprising the COI, COII and 5.8S rRNA genes and used maximum likelihood and Bayesian inference to estimate the phylogeny and divergence times of six out of the seven Anopheles subgenera. Our analysis reveals a monophyletic group composed of the three exclusively Neotropical subgenera, Stethomyia, Kerteszia and Nyssorhynchus, which began to diversify in the Late Cretaceous, at approximately 90 Ma. The inferred age of the last common ancestor of the Anopheles genus was ca. 110 Ma. The monophyly of all Anopheles subgenera was supported, although we failed to recover a significant level of statistical support for the monophyly of the Anopheles genus. The ages of the last common ancestors of the Neotropical clade and the Anopheles and Cellia subgenera were inferred to be at the Late Cretaceous (ca. 90 Ma). Our analysis failed to statistically support the monophyly of the Anopheles genus because of an unresolved polytomy between Bironella and A. squamifemur.
Topics: Animals; Anopheles; Electron Transport Complex IV; Evolution, Molecular; Genetic Variation; Insect Proteins; Mitochondrial Proteins; Phylogeny; Protein Subunits; RNA, Ribosomal, 5.8S; Species Specificity; Time Factors
PubMed: 26244561
DOI: 10.1371/journal.pone.0134462 -
Molecular Ecology Resources Jan 2022Anopheles is a diverse genus of mosquitoes comprising over 500 described species, including all known human malaria vectors. While a limited number of key vector species...
Anopheles is a diverse genus of mosquitoes comprising over 500 described species, including all known human malaria vectors. While a limited number of key vector species have been studied in detail, the goal of malaria elimination calls for surveillance of all potential vector species. Here, we develop a multilocus amplicon sequencing approach that targets 62 highly variable loci in the Anopheles genome and two conserved loci in the Plasmodium mitochondrion, simultaneously revealing both the mosquito species and whether that mosquito carries malaria parasites. We also develop a cheap, nondestructive, and high-throughput DNA extraction workflow that provides template DNA from single mosquitoes for the multiplex PCR, which means specimens producing unexpected results can be returned to for morphological examination. Over 1000 individual mosquitoes can be sequenced in a single MiSeq run, and we demonstrate the panel's power to assign species identity using sequencing data for 40 species from Africa, Southeast Asia, and South America. We also show that the approach can be used to resolve geographic population structure within An. gambiae and An. coluzzii populations, as the population structure determined based on these 62 loci from over 1000 mosquitoes closely mirrors that revealed through whole genome sequencing. The end-to-end approach is quick, inexpensive, robust, and accurate, which makes it a promising technique for very large-scale mosquito genetic surveillance and vector control.
Topics: Africa; Animals; Anopheles; Humans; Mosquito Vectors; Plasmodium
PubMed: 34053186
DOI: 10.1111/1755-0998.13436 -
Insecticide resistance in Anopheles mosquitoes : additional obstacles in the battle against malaria.Medecine Et Sante Tropicales Nov 2016Mosquitoes of the genus Anopheles are malaria vectors in tropical areas and were of course designated as primary targets by programs for malaria control. Repellent... (Review)
Review
Mosquitoes of the genus Anopheles are malaria vectors in tropical areas and were of course designated as primary targets by programs for malaria control. Repellent sprays, indoor use of insecticides, and massive delivery of mosquito nets are standard examples of the means widely used to combat malaria. This synthetic review supplies an overview of all of the modes of resistance developed by Anopheles mosquitoes against these human actions. The misuse of each available tool has gradually led to a decrease in its global effectiveness. Newly-emerging forms of resistance, due to modification or overexpression of molecular targets, as well as behavioral adaptations by mosquitoes, are some examples of the consequences. To enable a categorical reduction in malaria incidence, a thorough adjustment of the use of the various means of control should be envisioned.
Topics: Animals; Anopheles; Humans; Insect Control; Insecticide Resistance; Malaria
PubMed: 28073732
DOI: 10.1684/mst.2016.0634