Anopheles claviger | |
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Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Arthropoda |
Class: | Insecta |
Order: | Diptera |
Family: | Culicidae |
Genus: | Anopheles |
Subgenus: | Anopheles |
Species: | A. claviger |
Binomial name | |
Anopheles claviger (Meigen, 1804) | |
Anopheles claviger is a mosquito species found in Palearctic realm covering Europe, North Africa, northern Arabian Peninsula, and northern Asia. It is responsible for transmitting malaria in some of these regions. [1] [2] [3] The mosquito is made up of a species complex consisting of An. claviger sensu stricto and An. petragnani Del Vecchio. An. petragnani is found only in western Mediterranean region, and is reported to bite only animals; hence, it is not involved in human malaria.
It was on An. claviger that Giovanni Battista Grassi established the fact that only the female mosquitoes are responsible for transmitting malarial parasite Plasmodium falciparum in humans. [4]
Anopheles claviger was known for breeding abundantly in Åland. As a result, malaria was endemic in the islands for at least 150 years, with severe malaria outbreaks being recorded in the 17th century, and in 1853 and 1862. [5]
Anopheles claviger was first described by Johann Wilhelm Meigen in 1804. However due to its close resemblance with other anopheline mosquitoes, the systematics was variously changed. Originally Meigen named it Culex claviger which he changed it to An. bifurcutus in 1818. This was for a long period the accepted binomial but soon they realised that Carl Linnaeus had already used the name for the males of Culex pipiens . [1] After a decade James Francis Stephens renamed it An. grisescens in 1828. A number of scientific names was introduced after they were discovered from one region after another. Some recognised synonyms are: [6]
Italian biologists G. Del Vecchio in 1939 and G. Lupascu in 1941 were the first to notice that An. claviger comprised two morphologically distinct species. In 1962 M. Coluzzi revised the taxonomic status by classifying An. claviger as a species complex inclusive of An. petragnani. The species could be identified only on small structural variation in the pupal stages, [7] but is now identified using biochemical and molecular tools. [8] [9] [10]
Anopheles claviger is found throughout Palearctic ecozone including Afghanistan, Albania, Armenia, Austria, Azerbaijan, Belarus, Belgium, Bosnia and Herzegovina, Bulgaria, Croatia, Czech Republic, Denmark, Estonia, Finland, France, Georgia, Germany, Greece, Hungary, Iran, Iraq, Ireland, Israel, Italy, Jordan, Kyrgyzstan, Latvia, Lebanon, Lithuania, Moldova, Netherlands, Norway, Pakistan, Poland, Portugal, Romania, Russia, Slovakia, Slovenia, Spain, Sweden, Syria, Tajikistan, Turkey, Turkmenistan, Ukraine, United Kingdom, Uzbekistan, Serbia and Montenegro, [6] extending to Middle East, China and Siberia. [11] Member of the species complex An. petragnani is found only in western Mediterranean including France and Spain, up to Turkey, [12] and absent from beyond. [8]
Female An. claviger is distinguished from other related species from its brownish colour and dark palps. It is also generally larger than others. The proboscis is dark-brown while the antennae are brown. The scales on the wings are dark, evenly distributed without any dark spot. The thorax and abdomen are brown with lighter colour at the posterior end. An. petragnani are generally darker than typical An. claviger. Males are basically similar but have complex arrangements of setae with distinct gonostyle. [1]
Anopheles claviger adults are most abundant in May and September during which maximum biting on humans takes place. The larval forms are most abundant during cold season from October to the next April. Larvae are generally found in cool and clean water. In the Mediterranean region they are commonly found in wells and water containers (very common in cisterns). In cold area the larvae hibernate during winter but in warmer climate, they do not hibernate although development is slow. Larvae of An. petragnani are slightly different in that they can tolerate higher water temperature. Therefore they can be found during summer under rockholes, ditches, canals and river banks. Mature larvae develop in the eggs 5 to 7 days after oviposition. Most eggs hatch within the next three days, but some may take up to one month. Females of the second generation (September) generally lay fewer eggs than those of the first generation (May). Egg maturation requires blood meal and about six days are required for blood digestion. [13] Females attack human soon after they mate with males. They bite during broad daylight. [14] Females hardly live inside houses so that biting occurs in open places. Unlike other anopheline mosquitoes which deposit their eggs directly on the water surface, female An. claviger lays eggs just above the water level but still in the wet area. They are zoophilic in that they bite mostly of large mammals including humans. There is no report An. petragnani in transmission of human malaria, indicating that they are exclusively zoophilic. [1]
Anopheles claviger was experimentally used to discover the transmission of human malarial parasite P. falciparum, along with the fact that only female anophelines can transmit malaria. Before 1898 it was not known how malaria was transmitted. The Italian biologist Giovanni Battista Grassi started investigating different mosquito species in the early 1898 on the basis of mosquito-malaria theory. He suspected that only certain species were involved in transmission of malaria. In September Battista reported the presence of malarial parasite in An. claviger indicating it as malaria vector. Battista performed human experimentation on Abele Sola, who had been a patient for six years in the Hospital of the Holy Spirit (Ospedale di Santo Spirito in Sassia) in Rome. With mutual consent Sola was bitten by malaria-infected mosquitoes for ten nights, and after few weeks he was down with tertian malaria. Battista and his colleagues Amico Bignami, Giuseppe Bastianelli and Ettore Marchiafava continued to demonstrate the same experiments in other patients and were always successful. In November they found the parasites on the gut wall of the infected mosquitoes. [15] P. falciparum-carrying mosquito was no doubt the causative vector of malaria. They formally announced the discovery at the session of the Accademia dei Lincei on 4 December 1898. [4] [16] This experiment further established that An. claviger is the sole mosquito species responsible for human malaria in Italy, and other European countries. (In other parts of the world other species of Anopheles are responsible.) In addition the discovery laid the foundation for prevention of malaria by vector control of mosquitoes. [17] [18]
Mosquitoes, the Culicidae, are a family of small flies consisting of 3,600 species. The word mosquito is Spanish and Portuguese for little fly. Mosquitoes have a slender segmented body, one pair of wings, three pairs of long hair-like legs, and specialized, highly elongated, piercing-sucking mouthparts. All mosquitoes drink nectar from flowers; females of some species have in addition adapted to drink blood. Evolutionary biologists view mosquitoes as micropredators, small animals that parasitise larger ones by drinking their blood without immediately killing them. Medical parasitologists view mosquitoes instead as vectors of disease, carrying protozoan parasites or bacterial or viral pathogens from one host to another.
Sir Ronald Ross was a British medical doctor who received the Nobel Prize for Physiology or Medicine in 1902 for his work on the transmission of malaria, becoming the first British Nobel laureate, and the first born outside Europe. His discovery of the malarial parasite in the gastrointestinal tract of a mosquito in 1897 proved that malaria was transmitted by mosquitoes, and laid the foundation for the method of combating the disease.
Plasmodium is a genus of unicellular eukaryotes that are obligate parasites of vertebrates and insects. The life cycles of Plasmodium species involve development in a blood-feeding insect host which then injects parasites into a vertebrate host during a blood meal. Parasites grow within a vertebrate body tissue before entering the bloodstream to infect red blood cells. The ensuing destruction of host red blood cells can result in malaria. During this infection, some parasites are picked up by a blood-feeding insect, continuing the life cycle.
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.
Plasmodium falciparum is a unicellular protozoan parasite of humans, and the deadliest species of Plasmodium that causes malaria in humans. The parasite is transmitted through the bite of a female Anopheles mosquito and causes the disease's most dangerous form, falciparum malaria. It is responsible for around 50% of all malaria cases. P. falciparum is therefore regarded as the deadliest parasite in humans. It is also associated with the development of blood cancer and is classified as a Group 2A (probable) carcinogen.
Giovanni Battista Grassi was an Italian physician and zoologist, best known for his pioneering works on parasitology, especially on malariology. He was Professor of Comparative Zoology at the University of Catania from 1883, and Professor of Comparative Anatomy at Sapienza University of Rome from 1895 until his death. His first major research on the taxonomy and biology of termites earned him the Royal Society's Darwin Medal in 1896.
Culex or typical mosquitoes are a genus of mosquitoes, several species of which serve as vectors of one or more important diseases of birds, humans, and other animals. The diseases they vector include arbovirus infections such as West Nile virus, Japanese encephalitis, or St. Louis encephalitis, but also filariasis and avian malaria. They occur worldwide except for the extreme northern parts of the temperate zone, and are the most common form of mosquito encountered in some major U.S. cities, such as Los Angeles.
Amico Bignami was an Italian physician, pathologist, malariologist and sceptic. He was professor of pathology at Sapienza University of Rome. His most important scientific contribution was in the discovery of transmission of human malarial parasite in the mosquito.
Giuseppe Bastianelli was an Italian physician and zoologist who worked on malaria and was the personal physician of Pope Benedict XV.
The history of malaria extends from its prehistoric origin as a zoonotic disease in the primates of Africa through to the 21st century. A widespread and potentially lethal human infectious disease, at its peak malaria infested every continent except Antarctica. Its prevention and treatment have been targeted in science and medicine for hundreds of years. Since the discovery of the Plasmodium parasites which cause it, research attention has focused on their biology as well as that of the mosquitoes which transmit the parasites.
Anopheles walkeri is a species of mosquito found predominantly throughout the Mississippi River Valley, with its habitat ranging as far north as southern Quebec, Canada. The eggs of A. walkeri are laid directly on the water surface in freshwater swamp habitats. Since its eggs are not resistant to desiccation, this species is restricted to swampy regions with plenty of water. Anopheles walkeri, as with many other anophelines, begins to become active later in the evening than most other mosquito species in its range. This species becomes especially active late at night when in search of a blood meal. Feeding activity is affected greatly by environmental conditions within its microclimate. Wind, low humidity and cool temperatures, are all negatively correlated with feeding aggression.
Anopheles albimanus is a species of mosquito in the order Diptera. It is found in coastal Central and South America, the Caribbean, and Mexico. It is a generalist species and capable of wide dispersion. A. albimanus is a common malaria vector.
Anopheles stephensi is a primary mosquito vector of malaria in urban India and is included in the same subgenus as Anopheles gambiae, the primary malaria vector in Africa. A. gambiae consists of a complex of morphologically identical species of mosquitoes, along with all other major malaria vectors; however, A. stephensi has not yet been included in any of these complexes. Nevertheless, two races of A. stephensi exist based on differences in egg dimensions and the number of ridges on the eggs; A. s. stephensisensu stricto, the type form, is a competent malaria vector that takes place in urban areas, and A. s. mysorensis, the variety form, exists in rural areas and exhibits considerable zoophilic behaviour, making it a poor malaria vector. However, A. s. mysorensis is a detrimental vector in Iran. An intermediate form also exists in rural communities and peri-urban areas, though its vector status is unknown. About 12% of malaria cases in India are due to A. stephensi.
Anopheles darlingi, the American malaria mosquito, is a species of mosquito in the family Culicidae. A. darlingi is one of the major species of mosquito known to be responsible for malaria in the Amazonian regions. It has a wide range of geographic distribution that stretches from Mexico and Argentina but it has also been found to populate in areas affected by deforestation and environment changes due to humans.
Mosquito-malaria theory was a scientific theory developed in the latter half of the 19th century that solved the question of how malaria was transmitted. The theory proposed that malaria was transmitted by mosquitoes, in opposition to the centuries-old medical dogma that malaria was due to bad air, or miasma. The first scientific idea was postulated in 1851 by Charles E. Johnson, who argued that miasma had no direct relationship with malaria. Although Johnson's hypothesis was forgotten, the arrival and validation of the germ theory of diseases in the late 19th century began to shed new lights. When Charles Louis Alphonse Laveran discovered that malaria was caused by a protozoan parasite in 1880, the miasma theory began to subside.
Anopheles sinensis is a species of mosquito that transmits malaria as well as lymphatic filariasis. It is regarded as the most important vector of these human parasitic diseases in Southeast Asia. It is the primary vector of vivax malaria in many regions. In China it also transmits the filalarial parasite, and arthropod roundworm. In Japan it is also a vector of a roundworm Setaria digitata in sheep and goats.
Anopheles nili is a species of mosquito in the Culicidae family. It comprises the following elements: An. carnevalei, An. nili, An. ovengensis and An. somalicus. The scientific name of this species was first published in 1904 by Theobald. It is the main mosquito species found in the south Cameroon forest zone which bites humans. It is known as a problematic carrier of malaria, although newly discovered, closely related species in the same genus have also been found to interact with A. nili as a disease vector. In that, they both have similar feeding habits on local targets in the Cameroon region.
Anopheles (Cellia) karwari is a species complex of zoophilic mosquito belonging to the genus Anopheles. It is found in India, and Sri Lanka, Bangladesh, Sumatra, and Java. A. karwari is a member of the Maculatus Group and the second scarcest species reported from Indonesia. Female is blood sucking and involved in transmitting Plasmodium falciparum, thus an important malarial vector. It is considered a secondary vector in the Australian region, but its vectorial status in South-East Asia was unknown.
Anopheles (Cellia) vagus is a species complex of zoophilic mosquito belonging to the genus Anopheles. It is found in India, Sri Lanka and Indonesia. It is a potential natural vector of malarial parasite Plasmodium falciparum, and Japanese encephalitis virus. It is highly susceptible to insecticide deltamethrin and resistant to DDT.
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.
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