Disease vector in the context of "Parasitism"

Parasitism is a close relationship between species, where one organism, the parasite, lives (at least some of the time) on or inside another organism, the host, causing it some harm, and is adapted structurally to this way of life. The entomologist E. O. Wilson characterised parasites' way of feeding as "predators that eat prey in units of less than one". Parasites include single-celled protozoans such as the agents of malaria, sleeping sickness, and amoebic dysentery; animals such as hookworms, lice, mosquitoes, and vampire bats; fungi such as honey fungus and the agents of ringworm; and plants such as mistletoe, dodder, and the broomrapes.

There are six major parasitic strategies of exploitation of animal hosts, namely parasitic castration, directly transmitted parasitism (by contact), trophically-transmitted parasitism (by being eaten), vector-transmitted parasitism, parasitoidism, and micropredation. One major axis of classification concerns invasiveness: an endoparasite lives inside the host's body; an ectoparasite lives outside, on the host's surface.

Anopheles (/əˈnɒfɪliːz/) is a genus of mosquito first described by the German entomologist 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.

The genus Anopheles diverged from other mosquitoes approximately 100 million years ago (mya), and, like other mosquitoes, the eggs, larvae, and pupae are aquatic. The Anopheles larva has no respiratory siphon through which to breathe, so it breathes and feeds with its body horizontal to the surface of the water. The adult mosquito hatches from the surface and feeds on the nectar of flowers; the female mosquito also feeds on blood, which animal diet allows them to carry and transmit parasites between hosts. The adult's feeding position is head-down, unlike the horizontal stance of the culicines. Anopheles are distributed almost worldwide, throughout the tropics, the subtropics, and the temperate regions of planet Earth. In hot weather, adult Anopheles aestivate, which is a state of dormancy that enables the mosquito to survive in hot dry regions, such as the Sahel.

Mosquitoes, the Culicidae, are a family of small flies consisting of 3,600 species. The word mosquito (formed by mosca and diminutive -ito) 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 many species have adapted to also drink blood. The group diversified during the Cretaceous period. Evolutionary biologists view mosquitoes as micropredators, small animals that parasitise larger ones by drinking their blood without immediately killing them. Medical parasitologists view mosquitoes as vectors of disease, carrying protozoan parasites or bacterial or viral pathogens from one host to another.

The mosquito life cycle consists of four stages: egg, larva, pupa, and adult. Eggs are laid on the water surface; they hatch into motile larvae that feed on aquatic algae and organic material. These larvae are important food sources for many freshwater animals, such as dragonfly nymphs, many fish, and some birds. Adult females of many species have mouthparts adapted to pierce the skin of a host and feed on blood of a wide range of vertebrate hosts, and some invertebrates, primarily other arthropods. Some species only produce eggs after a blood meal.

Climate change affects human health in many ways, including an increase in heat-related illnesses and deaths, worsened air quality, the spread of infectious diseases, and health risks associated with extreme weather such as floods and storms. Rising global temperatures and changes in weather patterns are increasing the severity of heat waves and extreme weather events. These events in turn have direct and indirect impacts on human health. For example, when people are exposed to higher temperatures for longer time periods they might experience heat illness and heat-related death.

In addition to direct impacts, climate change and extreme weather events cause changes in biomes. Certain diseases that are carried and spread by living hosts such as mosquitoes and ticks (known as vectors) may become more common in some regions. Affected diseases include dengue fever and malaria. Contracting waterborne diseases such as diarrhoeal disease will also be more likely.

In epidemiology, vector incrimination refers to the process of proving that a particular species, a specific vector of disease, is responsible for the transmission of a pathogen to hosts. This study is used in the identification and control of mosquito species as carriers of diseases such as malaria.

In order to decide whether a species is responsible for the spread of a pathogen, a number of parameters must be examined. The abundance and presence of organisms within a species that are infected with a pathogen, the age and parity of a vector, and the feeding behaviours of the vector are some of these parameters. From here, professionals can calculate the biting rate, infectivity, vectorial capacity and inoculation rate of the vector. In mosquitoes, the condition of the abdomen and digestion can be used to determine how often they feed, and dissection of salivary glands can be used as detection for the presence of sporozoites of a pathogen.