Anopheles Atroparvus

''Anopheles atroparvus'' is a European species of mosquito, which was first identified in 1927. It is one of the most abundant palearctic Anopheles species belonging to the family Culicidae, commonly called mosquitoes. Although research interest in ''A. atroparvus'' has been low in the past several decades, recent concern for an increase in vector-borne disease has encouraged new research into this species.

''A. atroparvus'' underwent population reduction in many areas where it was once abundant due to pollution of natural habitats, vector control measures, and the reduction of suitable habitat through drying or flooding. It is the natural prey to many fish and insect species, and preys upon mainly humans, birds and livestock associated with farmland and farm dwellings.

Taxonomy

''A. atroparvus'' belongs to the subgenre ''Anopheles'' among a group defined by the ''maculipennis'' complex Differentiation between ''Anopheles'' species is often not possible at a phenotypic level but instead is observed in behavior, such as differences in habitats or hibernation habits, or variation at a genetic level.

Distribution and habitat

Distribution

Vastly distributed throughout most of Europe, specifically northern regions, with little or no known populations in Southern and South eastern Europe.5. Capinha, C., Gomes, E., Reis, E., Rocha, J., Sousa, C. A., Do Rosario, V. E., & Almeida, A. P. (2009). Present habitat suitability for ''Anopheles atroparvus'' (Diptera, Culicidae) and its coincidence with former malaria areas in mainland Portugal. Geospatial health, 177-187. ''A. atroparvus'' is currently assumed not to live in Italy, Greece or Turkey.Birnberg, L., Aranda, C., Talavera, S., Núñez, A. I., Escosa, R., & Busquets, N. (2020). Laboratory colonization and maintenance of ''Anopheles atroparvus'' from the Ebro Delta, Spain. Parasites & Vectors, 13(1), 1-5
Distribution of ''A. atroparvus'' is affected in some areas due to competition with related species. Other constraints on distribution depends on habitat suitability; ''A. atroparvus'' is limited by the need for water and vegetation to reproduce and minimize the risk of predation.
Because ''A. atroparvus'' tends to like warmer climate, global climate change could result in changing habitat distribution for ''A. atroparvus'' and it is generally considered to result in an increase in population density of the species.

Habitat

''A. atroparvus'' is common to both coastal and inland areas where short lived still water bodies are plentiful.
Adults live in close association with the animal and human blood hosts that it feeds on and tend to live in farm homes and other dwellings.
Suitable habitat for larval stages is mainly in wide, shallow non-permanent water bodies of brackish water, commonly in association with irrigated fields especially crops such as rice.Roiz, D., Ruiz, S., Soriguer, R., & Figuerola, J. (2015). Landscape effects on the presence, abundance and diversity of mosquitoes in Mediterranean wetlands. PLoS One, 10(6), e0128112.
Unlike many other species, ''A. atroparvus'' remains active in the winter months, at which time it will still take blood meals, but will not lay eggs.Talbalaghi, A., & Shaikevich, E. (2011). Molecular approach for identification of mosquito species (Diptera: Culicidae) in Province of Alessandria, Piedmont, Italy. European Journal of Entomology, 108(1), 35.Gowland, R. L., & Western, A. G. (2012). Morbidity in the marshes: Using spatial epidemiology to investigate skeletal evidence for malaria in Anglo‐Saxon England (AD 410–1050). American Journal of Physical Anthropology, 147(2), 301-311.
Their activity in the winter may result in an annual reduction in population as competition for food and shelter rises.
''A. atroparvus'' displays genetic diversity for protection against common insecticides used on crops, making it easier for them to live on farmland.Hemingway, J. (1982). Genetics of organophosphate and carbamate resistance in ''Anopheles atroparvus'' (Diptera: Culicidae). Journal of economic entomology, 75(6), 1055-1058.Ponçon, N., Toty, C., L'Ambert, G., Le Goff, G., Brengues, C., Schaffner, F., & Fontenille, D. (2007). Biology and dynamics of potential malaria vectors in Southern France. Malaria Journal, 6(1), 18

Life cycle

Adult ''A. atroparvus'' can be active feeders all year round, but cannot lay eggs in the winter and tend to dwell inside through the winter months.
They are most active during the summer months (June-July). During the warmer months, eggs are laid in suitable water bodies, where they will hatch and larva will remain in the water until they develop into adults.
Females have been recorded to have a short life span.Falcuta, E., Prioteasa, F. L., & Nicolescu, G. (2008). Investigations of the anopheline (Diptera: Culicidae) fauna from three areas belonging to the Danube Delta Biosphere Reserve in order to evaluate the risk of malaria re-emergence. Danube Delta National Institute Scientific Annals, 14, 15-20.

Larval stages require water for development and it is not until they become adults that they can survive a non-aquatic environment.
This species shows some adaptability when recent observations have recorded larvae present in small water bodies within towns such as overgrown roadsides, which were not considered suitable in the past.

Parasitology

''A. atroparvus'' is a well known historical vector for malaria (''Plasmodium'' spp) particularly throughout Europe and the UK, and is considered the main vector for malaria in many countries such as Romania, Portugal, France and the Netherlands.Cailly, P., Balenghien, T., Ezanno, P., Fontenille, D., Toty, C., & Tran, A. (2011). Role of the repartition of wetland breeding sites on the spatial distribution of Anopheles and Culex, human disease vectors in Southern France. Parasites & vectors, 4(1), 65
In Spain, ''A. atroparvus'' has been identified as the main vector for two different malaria parasites (''Plasmodium vivax'' & '' Plasmodium falciparum'').
Although malaria has been considered absent of natural strains in Europe, changing climate and human caused land conditioning via agriculture or environmental protection measures could cause an increase in population of ''A. atroparvus'' in areas where it used to be a main vector for the disease.Vicente, J. L., Sousa, C. A., Alten, B., Caglar, S. S., Falcutá, E., Latorre, J. M., ... & Toma, L. (2011). Genetic and phenotypic variation of the malaria vector ''Anopheles atroparvus'' in southern Europe. Malaria journal, 10(1), 5
Because ''A. atroparvus'' is still active in the winter and tend to live in dwellings with their blood meals, this can result in multiple infection in the same household.

Control

In the past, measures such as introducing fish and insect species that prey on ''A. atroparvus'' to water bodies has been used to decrease the presence of the malaria vector.Takken, W., Geene, R., Adam, W., Jetten, T. H., & van der Velden, J. A. (2002). Distribution and dynamics of larval populations of ''Anopheles messeae'' and ''A. atroparvus'' in the delta of the rivers Rhine and Meuse, The Netherlands. AMBIO: A Journal of the Human Environment, 31(3), 212-218Brugman, V. A., Hernández-Triana, L. M., England, M. E., Medlock, J. M., Mertens, P. P., Logan, J. G., ... & Carpenter, S. (2017). Blood-feeding patterns of native mosquitoes and insights into their potential role as pathogen vectors in the Thames estuary region of the United Kingdom. Parasites & vectors, 10(1), 163.
Household measures were also introduced and effectively reduced malaria contraction via reduction in ''A. atroparvus'' populations. this included indoor DDT insecticide sprays and bug nets for windows and doors.
Through both intentional control of ''A. atroparvus'' and other factors such as pollution to ''A. atroparvus'' breeding grounds in the Netherlands, the decrease of this vector species led to the elimination of malaria from Europe.
although primarily research suggests that climate change would serve to increase ''A. atroparvus'' populations, there are also implications that it may instead adversely affect populations by reducing water bodies and rainfall that are required for reproduction.
There is also concern over vector control as ''A. atroparvus'' could become infected with ''Plasmodium'' species that have been imported from areas where malaria is more abundant.

References

{{Taxonbar, from=Q567661

Anopheles
Fauna of Europe