Culex quinquefasciatus | |
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Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Arthropoda |
Class: | Insecta |
Order: | Diptera |
Family: | Culicidae |
Genus: | Culex |
Species: | C. quinquefasciatus |
Binomial name | |
Culex quinquefasciatus Say, 1823 | |
Synonyms | |
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Culex quinquefasciatus (originally named Culex fatigans), commonly known as the southern house mosquito, is a medium-sized mosquito found in tropical and subtropical regions of the world. It is a vector of Wuchereria bancrofti , avian malaria, and arboviruses including St. Louis encephalitis virus, Western equine encephalitis virus, Zika virus [1] and West Nile virus. [2] [3] It is taxonomically regarded as a member of the Culex pipiens species complex. [4] [5] Its genome was sequenced in 2010, and was shown to have 18,883 protein-coding genes. [6]
American entomologist Thomas Say described Culex quinquefasciatus, which he collected along the Mississippi River, in 1823. Originally written as "C. 5-fasciatus", the name refers to 5 (quinque) black, broad, transverse bands ("fasciatus" or "fasciae") on the mosquito's dorsal abdomen. The name remains despite later revelations of more than 5 fasciae, thanks to improved microscopy. Although quinquefasciatus is the official scientific name, there are at least 5 synonymous names for this species. [7]
Cx. quinquefasciatus is a member of the Culex pipiens species complex. [4] [5] Smith et al. 2004 develop an assay specifically for this complex and use it to confirm that it does encompass this species. [4]
The adult C. quinquefasciatus is a medium-sized mosquito and is brown in colour. The body is about 3.96 to 4.25 mm long. While the main body is brown, the proboscis, thorax, wings, and tarsi are darker than the rest of the body. The head is light brown, with the lightest portion in the center. The antennae and the proboscis are about the same length, but in some cases, the antennae are slightly shorter than the proboscis. The flagellum has 13 segments that may have few or no scales. The scales of the thorax are narrow and curved. The abdomen has pale, narrow, rounded bands on the basal side of each tergite. Males can be differentiated from females in having large palps and feathery antennae. [8]
The larva has a short and stout head. The mouth brushes have long yellow filaments used for filtering organic materials. The abdomen consists of eight segments, the siphon, and the saddle. Each segment has a unique setae pattern. The siphon is on the dorsal side of the abdomen, and is four times longer than its breadth. The siphon has multiple setae tufts. The saddle is barrel-shaped and located on the ventral side of the abdomen, with four long anal papillae protruding from the posterior end. [2]
Mature C. quinquefasciatus females fly at night to nutrient-rich standing water to lay eggs. They breed profusely in dirty water collections, including stagnant drains, cesspools, septic tanks with leaks, burrow pits, and almost all organic polluted water collections. A single female can lay up to five rafts of eggs in a lifetime, with each raft containing 100 to 300 eggs. [9] The exact number varies depending on climatic conditions. [2] The larvae feed on organic material in the water and require between five and eight days to complete their development at 30 °C (86 °F). The larvae pass through four larval instars, and towards the end of the fourth instar, they stop eating and undergo moulting to give rise to pupae. After 36 hours at 27 °C (81 °F), adults emerge. The exact timing of development can vary depending on temperature. In optimum temperature and humidity, the lifecycle will be completed in seven days, passing through the egg, larval, pupal, and adult stages.[ citation needed ]
Both male and female adults take sugar meals from plants. After mating, the female seeks a blood meal from a mammal or bird, as ingested blood is necessary for egg development. C. quinquefasciatus shows a preference for the blood of birds, but will also commonly bite humans. [10]
Known hosts include birds (Aves), cattle (Bos taurus), dogs (Canis familiaris), Equus including donkeys (E. asinus), cats (Felis), mice (Mus musculus), house sparrows (Passer domesticus), rats (Rattus) and boars (Sus scrofa). [11]
"Quinx" are among the world's most abundant peridomestic mosquitoes, earning the nickname "southern house mosquito". The species' place of origin is uncertain. It may have been native to the lowlands of West Africa, or to Southeast Asia. [11] Cx. quinquefasciatus is now found throughout subtropical and tropical areas worldwide, including the Americas, Australia and New Zealand, [12] except for exceedingly dry or cold regions. Thomas Say described the species as "exceedingly numerous and troublesome". It rests in trees and high places. [10]
The southern house mosquito is a principal vector of numerous pathogens, transmitting the phlebovirus Rift Valley fever virus, and the two flaviviruses St. Louis encephalitis virus and West Nile virus, plus filarial worms and avian malarial parasites. [7]
It transmits zoonotic diseases that affect humans and wild and domestic animals, such as lymphatic filariasis, avian malaria, St. Louis encephalitis, Western equine encephalitis, and West Nile fever, and may be a vector of the Zika virus. [13] It causes infection through biting during blood meal. In the southern U.S., it is the primary vector of St. Louis encephalitis virus. In India and Southeast Asia, it is the primary vector of Wuchereria bancrofti , a nematode that causes lymphatic filariasis. It acts as an intermediate host for the helminth parasite by harbouring the larval stages. [14] In Hawaii, it is the principal vector of avian malaria ( Plasmodium relictum), to which historic extinctions and significant contemporary population declines in Hawaii's native honeycreeper species are attributed. It is the definitive host for the malarial parasite as it harbours the sexual cycle. [15] In 2013 West Nile Virus positive specimens were collected in Southern California. [16] [ failed verification ]
Mosquitoes are approximately 3,600 species of small flies comprising the family Culicidae. The word "mosquito" is Spanish for "little fly". Mosquitoes have a slender segmented body, one pair of wings, one pair of halteres, three pairs of long hair-like legs, and elongated mouthparts.
West Nile fever is an infection by the West Nile virus, which is typically spread by mosquitoes. In about 80% of infections people have few or no symptoms. About 20% of people develop a fever, headache, vomiting, or a rash. In less than 1% of people, encephalitis or meningitis occurs, with associated neck stiffness, confusion, or seizures. Recovery may take weeks to months. The risk of death among those in whom the nervous system is affected is about 10 percent.
Aedes albopictus, from the mosquito (Culicidae) family, also known as the (Asian) tiger mosquito or forest mosquito, is a mosquito native to the tropical and subtropical areas of Southeast Asia. In the past few centuries, however, this species has spread to many countries through the transport of goods and international travel. It is characterized by the white bands on its legs and body.
Wuchereria bancrofti is a filarial (arthropod-borne) nematode (roundworm) that is the major cause of lymphatic filariasis. It is one of the three parasitic worms, together with Brugia malayi and B. timori, that infect the lymphatic system to cause lymphatic filariasis. These filarial worms are spread by a variety of mosquito vector species. W. bancrofti is the most prevalent of the three and affects over 120 million people, primarily in Central Africa and the Nile delta, South and Central America, the tropical regions of Asia including southern China, and the Pacific islands. If left untreated, the infection can develop into lymphatic filariasis. In rare conditions, it also causes tropical pulmonary eosinophilia. No vaccine is commercially available, but high rates of cure have been achieved with various antifilarial regimens, and lymphatic filariasis is the target of the World Health Organization Global Program to Eliminate Lymphatic Filariasis with the aim to eradicate the disease as a public-health problem by 2020. However, this goal was not met by 2020.
Arbovirus is an informal name for any virus that is transmitted by arthropod vectors. The term arbovirus is a portmanteau word. Tibovirus is sometimes used to more specifically describe viruses transmitted by ticks, a superorder within the arthropods. Arboviruses can affect both animals and plants. In humans, symptoms of arbovirus infection generally occur 3–15 days after exposure to the virus and last three or four days. The most common clinical features of infection are fever, headache, and malaise, but encephalitis and viral hemorrhagic fever may also occur.
Culex or the typical mosquitos 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.
The discipline of medical entomology, or public health entomology, and also veterinary entomology is focused upon insects and arthropods that impact human health. Veterinary entomology is included in this category, because many animal diseases can "jump species" and become a human health threat, for example, bovine encephalitis. Medical entomology also includes scientific research on the behavior, ecology, and epidemiology of arthropod disease vectors, and involves a tremendous outreach to the public, including local and state officials and other stake holders in the interest of public safety.
The London Underground mosquito is a form of mosquito in the genus Culex. It is found in the London Underground railway system as its name suggests, but has a worldwide distribution and long predates the existence of the London Underground. It was first described as a distinct species from Egyptian specimens by the biologist Peter Forsskål (1732–1763). He named this mosquito Culex molestus due to its voracious biting, but later biologists renamed it Culex pipiens f. molestus because there were no morphological differences between it and Culex pipiens. Notably, this mosquito assaulted Londoners sleeping in the Underground during the Blitz, although similar populations were long known.
Culex pipiens is a species of mosquito commonly referred to as the common house mosquito or northern house mosquito, as it is the most common mosquito to the northern regions of the US. They can be found in both urban and suburban temperate and tropical regions across the world.
Culex restuans is a species of mosquito known to occur in Canada, the United States, Mexico, Guatemala, Honduras, and the Bahamas. It is a disease vector for St. Louis encephalitis and West Nile virus. In 2013 West Nile Virus positive specimens were collected in Southern California.
Culex annulirostris, commonly known as the common banded mosquito, is an insect native to Australia, Fiji, Micronesia, the Philippines and Indonesia. It is regarded as a serious pest species throughout its range.
Mosquito-borne diseases or mosquito-borne illnesses are diseases caused by bacteria, viruses or parasites transmitted by mosquitoes. Nearly 700 million people get a mosquito-borne illness each year resulting in over 725,000 deaths.
Aedes triseriatus is a member of the true fly order. It is called the eastern tree hole mosquito due to its predilection towards breeding in stagnant water that is found in natural holding containers such as tree holes. It is native to the eastern United States and southern Canada and favors hardwood habitats. It has been found as far south as the Florida Keys, as far west as Idaho and Utah, and as far north as Quebec and Ontario. This species has not yet been found in Europe, but it has the potential to spread through international trade. In 2004, it was found in a shipment of tires travelling from Louisiana to France, but it was identified and targeted with insecticides that truncated its spread. It is a known vector of La Crosse encephalitis and canine heartworm disease. In the laboratory, it has been found to vector several other viruses including yellow fever, eastern encephalitis, Venezuelan encephalitis, and western encephalitis. Because of its potential for international spread and its proclivity for transmitting disease, monitoring the distribution of this species is essential.
Rocio viral encephalitis is an epidemic flaviviral disease of humans first observed in São Paulo State, Brazil, in 1975. Low-level enzootic transmission is likely continuing in the epidemic zone, and with increased deforestation and population expansion, additional epidemics caused by Rocio virus are highly probable. If migratory species of birds are, or become involved in, the virus transmission cycle, the competency of a wide variety of mosquito species for transmitting Rocio virus experimentally suggest that the virus may become more widely distributed. The encephalitis outbreak in the western hemisphere caused by West Nile virus, a related flavivirus, highlights the potential for arboviruses to cause severe problems far from their source enzootic foci.
Usutu virus (USUV) is a flavivirus belonging to the Japanese encephalitis complex, which is an emerging zoonotic arbovirus of concern because of its pathogenicity to humans and its similarity in ecology with other emerging arboviruses such as West Nile virus. It mainly infects Culex mosquitoes and birds; humans form a dead-end host. First identified in South Africa in 1959, the virus has caused outbreaks in birds across Europe since 1996. Nearly 50 cases in humans have been reported as of 2019, mainly in Europe. These are predominantly asymptomatic, but some people experience neurological symptoms.
Culex modestus is a species of blood-feeding mosquito of the family Culicidae. It has been experimentally demonstrated to be capable of transmitting West Nile virus (WNV), and its habit of feeding aggressively on both birds and humans gives it significant potential for transmission of zoonotic infections from birds to humans. It is believed to be the principle bridge vector of WNV between birds and humans in southern France and is thought to have played a role in WNV transmission in the Danube delta, Caspian and Azov sea deltas, and the Volga region in Russia. It has also been implicated in Tahyna virus and Lednice virus transmission in France and Slovakia, respectively.
Spondweni virus is an arbovirus, or arthropod-borne virus, which is a member of the family Flaviviridae and the genus Flavivirus. It is part of the Spondweni serogroup which consists of the Sponweni virus and the Zika virus (ZIKV). The Spondweni virus was first isolated in Nigeria in 1952, and ever since, SPONV transmission and activity have been reported throughout Africa. Its primary vector of transmission is the sylvatic mosquito Aedes circumluteolus, though it has been isolated from several different types of mosquito. Transmission of the virus into humans can lead to a viral infection known as Spondweni fever, with symptoms ranging from headache and nausea to myalgia and arthralgia. However, as SPONV is phylogenetically close to the ZIKV, it is commonly misdiagnosed as ZIKV along with other viral illnesses.
West Nile virus (WNV) is a single-stranded RNA virus that causes West Nile fever. It is a member of the family Flaviviridae, from the genus Flavivirus, which also contains the Zika virus, dengue virus, and yellow fever virus. The virus is primarily transmitted by mosquitoes, mostly species of Culex. The primary hosts of WNV are birds, so that the virus remains within a "bird–mosquito–bird" transmission cycle. The virus is genetically related to the Japanese encephalitis family of viruses. Humans and horses both exhibit disease symptoms from the virus, and symptoms rarely occur in other animals.
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