The malarial mosquito is a carrier of malaria. Malaria mosquito Types of malaria mosquitoes

For mosquitoes (order Diptera, suborder Long-whiskers) characteristic external features are the subtle body, long legs and a small head with proboscis-type mouthparts. Mosquitoes are ubiquitous, especially in warm, humid climates. Mosquitoes are carriers of over 50 diseases. Mosquitoes - representatives of the genera Culex and ncdcs (non-malarial) are carriers of pathogens of Japanese encephalitis, yellow fever, anthrax, representatives of the genus nnopheles (malarial mosquitoes) - carriers of malarial plasmodium. Nonmalarial and malarial mosquitoes differ from each other at all stages life cycle.

All mosquitoes lay their eggs in water or moist soil near bodies of water. Eggs of mosquitoes of the genus nnopheles are located on the surface of the water one at a time, each egg has two air floats. Their larvae are located under water parallel to its surface, on the penultimate segment they have two respiratory openings. The pupae are comma-shaped, develop under the surface of the water and breathe oxygen through breathing horns in the form of wide funnels. Adult mosquitoes of the genus nnopheles, sitting on objects, raise the body up, and hold the head down, forming sharp corner with surface. On both sides of their proboscis are mandibular palps equal in length to it. Mosquitoes of the genera Culex and Aedes lay eggs in groups in the water. Larvae in water lie at an angle to its surface and have a long respiratory siphon on the penultimate segment. The pupae also have the appearance of a comma, but their respiratory horns are shaped like thin cylindrical tubes. The mandibular palps of adult mosquitoes barely reach a third of the length of the proboscis. Sitting on objects, mosquitoes keep the body parallel to their surface.

The malarial mosquito is the definitive host, while humans are intermediate host the simplest malarial plasmodium (a type of sporozoans). The development cycle of malarial plasmodium consists of three parts:

1) schizogony - asexual reproduction by multiple division;

2) gametogony - sexual reproduction;

3) sporogony - the formation of forms specific for sporozoans (sporozoites).

Piercing the skin of a healthy person, an invasive mosquito injects into his blood saliva containing sporozoites, which are introduced into gametocytes in the liver cells. There they turn first into trophozoites, then into schizonts.

Detachment includes the largest number species that have medical significance. Representatives of the detachment have one (anterior) pair of membranous transparent or colored wings. The rear pair has turned into small haltere appendages that perform the function of balance organs. The head is spherical or hemispherical, connected to the chest by a thin soft stalk, which leads to greater mobility.

Diptera are divided into two suborders:

1. long-whiskered (mosquitoes and related groups)
2. short-whiskered (flies and related groups)

Suborder Long-whiskers

The most important representatives: mosquitoes, mosquitoes, midges

• Mosquitoes (Culicidae). Blood-sucking insects. Distributed from the tundra zone to the desert oases. Three genera are most often found on the territory of the former USSR - Anopheles (anopheles), Culex (Culex), Aёdes (aedes)

Imaginal forms of insects are small in size. The head bears large compound eyes, antennae and mouthparts.

Only females with a piercing-sucking apparatus are blood-sucking. It consists of a lower lip in the form of a gutter, an upper lip in the form of a plate that closes the gutter from above, a pair of lower and a pair of upper jaws in the form of bristles (stabbing apparatus) and a tongue (hypopharynx), inside which a canal passes. salivary gland. All stabbing parts lie in a case formed by the lower and upper lip. Appendages lower jaws serve as mandibular palps.

In males, the apparatus is sucking, the stabbing parts are reduced. They feed on the nectar of flowers. On the sides of the mouth apparatus are antennae, consisting of 14-15 segments, in males they are covered with long hairs, in females - short.

Development since complete transformation: egg, larva, pupa, adult. Eggs are laid in water or moist soil, breeding sites, depending on the genus of mosquitoes, can be natural and artificial reservoirs (puddles, ponds, ditches, water pits, irrigation and drainage canals, water barrels, rice fields, tree hollows, etc. .).

Before pupation, the larva actively feeds and molts several times. The body of the larva is clearly divided into the head, thorax and abdomen. The head is rounded, bears antennae, eyes and fan-shaped fans. While moving, the vanes drive water with the particles contained in it into the mouth of the larvae. The larva swallows any particles of a certain size, regardless of whether they are food or not. This is the basis for the use of pesticides sprayed in water bodies. The respiratory organs are the trachea and tracheal gills.

The pupa has the shape of a comma due to the massive cephalothorax and narrow abdomen, it does not feed, it moves with the help of quick flaps of the abdomen.

Hatched females and males live near water bodies, feeding on nectar. After fertilization, the female needs to drink blood to develop eggs. She searches for prey and sucks the blood of animals or humans. During the digestion of blood, maturation of eggs occurs (gonotrophic cycle), which lasts 2-3 days, but depending on the conditions, it may be delayed. Some mosquito species have only one gonotrophic cycle per summer (monocyclic), others may have several cycles (polycyclic).

The life expectancy of a female in the warm season is up to 3 months. Males live 10-15 days; in autumn and early winter, males die.

For the winter, larval and imaginal forms of females fall into a state of diapause. Diapause - inhibition of development at one of the stages of the life cycle, adapted to wintering. Most species of the genus Anopheles and Culex overwinter in the state of adults (female), Aedes - in the state of eggs.

Each type of mosquito has its own characteristics of ecology, so the organization of control measures requires an accurate definition of the genus present in the area. To do this, it is necessary to dwell on the signs that are important for the differential diagnosis of various genera of mosquitoes. Differences exist at all stages of the cycle .

egg laying

In mosquitoes of the genus Culex, eggs stick together during laying and form a "boat" that floats in the water. The eggs of mosquitoes of the genus Anopheles are bordered by a concave belt, equipped with air chambers and swim separately. Mosquitoes of the genus Aedes lay their eggs one at a time at the bottom of drying ponds.

Larval forms

Larvae of mosquitoes of the genus Culex and Aedes have a respiratory siphon on the penultimate segment of the abdomen in the form of a narrow tube with a stigma at the free end. Due to this, the larvae are located at an angle to the surface of the water. They can live in heavily polluted waters.

Larvae of mosquitoes of the genus Anopheles do not have a siphon, they have a pair of stigmas on the dorsal side of the penultimate segment, and therefore the larvae are located strictly parallel to the water surface. The hairs located on the segments help them to stay in this position. They live exclusively in clean or almost clean water bodies.

The Aedes larva lives in temporarily drying up reservoirs, puddles, ditches, hollows of trees, vessels with water, and can live in heavily polluted reservoirs.

pupae

Mosquito pupae on the dorsal side of the cephalothorax have a pair of respiratory siphons or tubules. With their help, the pupa is suspended from the surface film of water.

A distinctive feature of different genera of mosquitoes is the shape of the respiratory siphons. In mosquitoes of the genus Culex and Aedes, the siphons are cylindrical, while in the genus Anopheles, they are funnel-shaped.

Winged forms

Differences are manifested in the structure of the appendages of the head, the color of the wings and landing.

In Anopheles females, the mandibular palps are equal in length to the proboscis, in Culex females they are shorter than the proboscis and make up approximately 1/3-1/4 of its length.

There are dark spots on the wings of the malarial mosquito, which mosquitoes of the genus Culex do not have.

When landing, the abdomen of mosquitoes of the Anopheles genus is raised and is at an angle to the surface, while in the Culex genus, the abdomen is parallel to the surface.

The control of mosquitoes as vectors of the malaria pathogen requires a detailed study of the biology of the mosquito. Winged mosquitoes (imago) Anopheles maculipennis live near human dwellings. They inhabit various non-residential buildings located near the places of their breeding (various reservoirs). Here you can find males and young, not yet drinking the blood of females. During the day they sit motionless, hiding in dark corners. At dusk, they fly out in search of food. Food is found by smell. They feed on plant juices, they can drink a solution of sugar, milk, liquid from cesspools. After mating, females begin to drink blood, because without it, eggs do not develop in their body. To satisfy the "thirst for blood" females attack humans, domestic and wild animals. When animals accumulate, mosquitoes smell them at a distance of up to 3 km.

The female sucks blood from 0.5 to 2 minutes and drinks more blood than her body weighs (up to 3 mg). After drinking blood, the females fly away to a dark place, where they sit for 2-12 days, digesting food. At this time, they are easiest to find in human dwellings and livestock buildings. Given the migration of mosquitoes from water bodies to feeding places, Soviet malariologists proposed, when planning new rural construction, to place buildings for animals between water bodies and living quarters. In this case, barnyards become like a barrier that traps mosquitoes (zooprophylaxis of malaria).

In spring and summer, after a single sucking of blood, eggs are formed in the body of the female. In autumn, the pumped blood goes to the formation of a fatty body and the eggs do not develop. Obesity enables the female to overwinter. For wintering, mosquitoes fly to basements, cellars, pantries and rooms for animals, where there is no light and drafts. The winter is spent in a state of stupor. A. maculipennis tolerates cold well. By the middle of winter, females acquire the ability to lay eggs after a single blood meal. However, departure from wintering grounds and search for food occur only on warm days.

After maturation of eggs, the female migrates to the reservoir. Lays eggs on the fly or sitting on aquatic plants. Overwintered females produce the first laying of eggs in spring. Much later, spring and summer females begin to lay eggs. Having laid their eggs, they again fly in search of food, suck blood, and after maturation of the eggs again lay them in the reservoir. There may be several such cycles.

Unlike other mosquitoes, Anopheles lays its eggs scattered, without sticking them to each other. The eggs have air chambers and float on the surface of the water. After 2-14 days, larvae emerge from them. Anopheles larvae respire atmospheric air. They can be found near the surface film of water. On this basis, they are easy to distinguish from the larvae of twitching mosquitoes and pusher mosquitoes, leading a bottom lifestyle. The larvae of Culex and Aedes mosquitoes are also found near the surface film. They are distinguished from the larvae of the malarial mosquito by a special respiratory tube - a siphon, extending from the penultimate segment of the abdomen. With the help of a siphon, they are suspended from the surface film of water. Malaria mosquito larvae do not have a siphon. When breathing, their body is parallel to the surface of the reservoir; air enters the trachea through the spiracles.

The larvae feed on microscopic organisms. They vigorously move the appendages of the head (fans) and create a fluid current that brings to the mouth organs everything that is in the surface layer of water. The larva without choice swallows any particles that do not exceed a certain size. In this regard, when using dust-like pesticides to control mosquito larvae, it is necessary to take into account the size of their particles.

The period of larval development consists of four stages (ages), separated from each other by molts. Larvae of the fourth age after molting turn into pupae. The pupa looks like a comma. In the anterior expanded section is the head and chest; behind is a thin abdomen of 9 segments. Anopheles pupae differ from Cules and Aedes pupae in the shape of the respiratory siphon. In pupae of the malarial mosquito, it has the shape of a cone ("postal horn"), in non-malarial mosquitoes, the siphon is cylindrical. At this stage, metamorphosis occurs, after which the imago (winged mosquito) emerges from the chitinous shell of the pupa. All development in water, from egg laying to adult emergence, lasts 14-30 days, depending on the temperature.

Mosquito control is an essential part of the malaria eradication effort. Malaria is an obligately transmissible disease and its pathogen is transmitted only by mosquitoes of the Anopheles genus.

The destruction of mosquitoes is carried out at all stages of their life cycle. winged mosquitoes in summer time they are destroyed in the places of their days, and in the fall and at the beginning of winter - in the places of wintering. To do this, rooms in which mosquitoes accumulate are subjected to dusting or spraying with insecticides. DDT and hexachloran preparations are used in the form of powders (dusts), liquid emulsions and aerosols.

To combat larvae and pupae, a survey of reservoirs is carried out. Only some of them can serve as breeding grounds malarial mosquitoes. Such anophelogenic water bodies must have a whole range of conditions that meet the needs of life and development of larvae. Anopheles larvae live in relatively clean oligosaprobic (see p. 326) water bodies with microplankton for food and sufficient dissolved oxygen. Larvae do not live in highly saline water bodies. Fast-flowing rivers and streams are also not used. However, their coastal zone can serve as a breeding ground for mosquitoes. Waves and even ripples prevent the larvae from breathing. Of essential importance is the nature of the vegetation of the reservoir and the illumination of its surface with direct sunlight. In heavily shaded forest water bodies, the larvae of the malaria mosquito do not live.

When fighting mosquito larvae, small water bodies that are not needed for economic purposes are covered with earth. Larger reservoirs that are not used for fish breeding and economic purposes are subjected to oiling or treated with pesticides. Oil, spreading over the surface of the water in the form of a very thin film, closes the spiracles of the larvae and kills them. Good results are obtained by the biological method of control: the settlement of anophelogenic reservoirs with tropical fish, mosquitoes, devouring larvae and pupae of mosquitoes. In rice fields, short-term descent of water (intermittent irrigation) is used.

Prevention and control measures. Personal - protection against mosquito bites. Public prevention: the main activities are the destruction of larval forms and breeding sites. Pupae, since they do not feed and are protected by thick chitin, are not susceptible to various kinds of influences.

The fight against larvae consists of a number of activities:

1. destruction of any small abandoned water tanks;
2. spraying in reservoirs serving as breeding sites, pesticides;
3. oiling of reservoirs, preventing the flow of oxygen;
4. a change in the type of vegetation in a reservoir or a change in the degree of its overgrowth;
5. drainage of the area, land reclamation works;
6. biological control measures are used mainly in water bodies in which agricultural crops grow, for example, rice fields, where live-bearing fish are bred - gambusia, feeding on mosquito larvae;
7. zooprophylaxis - when designing settlements between potential places livestock farms have mosquito breeding and residential buildings, as mosquitoes willingly feed on the blood of animals;
8. spraying insecticides in rooms where mosquitoes hibernate: basements, attics, barnyards, outbuildings. All insecticides are used so as not to harm the animal and plant world.

Distributed in warm and hot areas of the globe. Habitat - south of Europe, middle and south Asia, North Africa. Can live in wild nature and in settlements. Habitats in settlements are the burrows of house rodents, the space under the floors of residential buildings, at the base of adobe buildings, under heaps construction debris etc. In the wild, the breeding grounds are rodent burrows (gerbils, ground squirrels, etc.), bird nests, dens of jackals, foxes, caves, cracks, tree hollows. From their burrows, mosquitoes fly to settlements located up to 1.5 km away, which is important for the spread of diseases.

Mosquitoes - small insects - body length 1.5-3.5 mm. The color is brown-gray or light yellow. The head is small, with a short piercing-sucking apparatus, antennae and compound eyes. The widest part of the body is the chest, the abdomen consists of ten segments, of which the last two are modified and represent the outer parts of the genital apparatus. The legs are long and thin. The body and wings are heavily covered with hairs.

Males feed on plant sap. Only females drink blood, although they can also feed on sugary liquids. Females attack animals and humans before sunset and in the first hours after sunset outdoors and indoors. A person in the injection site feels itching and burning; blisters form. In sensitive individuals, intoxication manifests itself in the form of general weakness, headaches, loss of appetite and insomnia. When a person is injected with a mosquito P. pappatasii with the saliva of the latter, the causative agent of a viral disease - pappataci fever can be introduced. IN Central Asia and India, mosquitoes also serve as carriers of pathogens of cutaneous and visceral leishmaniasis.

Females lay up to 30 eggs 5-10 days after sucking blood. The eggs are elongated-oval in shape, after some time after laying they become brown in color. Development proceeds with complete metamorphosis. In the process of development, the larva goes through 4 stages. The worm-like legless larvae emerging from the eggs with a rounded head covered with hairs live in the soil and feed on decaying organic matter. They can be found in animal stalls, dirt-floored rooms, undergrounds, and garbage dumps. In nature, they develop in rodent burrows and bird nests. After the fourth molt, a club-shaped pupa is formed, from which, at the end of metamorphosis, a winged insect emerges. The pupa does not eat.

Like female mosquitoes, female mosquitoes have a gonotrophic cycle. However, many species of mosquitoes suck blood repeatedly during the maturation of eggs. Capable of transovarial transmission of pathogens.

Prevention and control measures. In the villages, the treatment of residential premises with insecticides is used, in natural conditions kill rodents in burrows.

The whole mass of flying blood-sucking dipterous insects is called midges. IN Siberian taiga, the tundra and other places, at times dipterous bloodsuckers appear in myriad quantities, attack animals and humans in clouds, clog the nose, throat, and ears.

The predominant part of the taiga midges are midges. Of these, the most important is the genus Culicoides, which has a number of species. These are the smallest of the blood-sucking insects (1-2 mm in length). Reproducing, they lay eggs in water or on damp earth. They attack around the clock, but mostly in the evening and at night. Only the female sucks blood. Saliva has a toxic effect and mass injections are extremely painful.

Another important component of the midges are midges, blood-sucking insects from the genus Simulium. They are distributed in various parts of the globe, but they are carriers of diseases only in Africa, South and Central America, where onchocerciasis pathogens are carried. The sizes are small, from 1.5 to 5 mm. The color is dark or dark brown. The body is thick and short, the legs and antennae are also short. The proboscis is short and thick, its length is much less than the diameter of the head. Blood-sucking only females that attack outdoors during daylight hours.

They live in damp wooded areas. Development occurs in fast-flowing, rapids rivers and streams, on the water of which, when laying eggs, females descend. Females attach eggs to aquatic plants and stones submerged in water. The larvae live in the water. They have a worm-like shape, developed organs of attachment to underwater objects in the form of outgrowths equipped with hooks. The pupae are inside cocoons tightly attached to underwater objects.

They attack during daylight hours. Cause itching, swelling, and mass attacks- General intoxication of the body. There have been cases of animal deaths. There are indications that some species may be carriers of tularemia pathogens.

Control measures.

When protecting against midges, fumigation is used (burning pyrethrum smoking candles, kindling smoking fires from leaves, manure, etc.). For personal protection, E. N. Pavlovsky recommends scaring nets (pieces of a fishing net soaked in special mixtures that repel insects). The net is thrown over the headdress, lowering it over the shoulders. To combat the larvae, the flowing water is treated with liquid insecticides.

Suborder short-whiskers

The most important representatives: flies, gadflies and horseflies

Some types of flies are closely related to humans (commensal), these include the housefly, housefly, autumn stingray.

• Housefly (Musca domestica). Spread throughout globe. An ordinary inhabitant of a human dwelling and a mechanical carrier of pathogens of a number of diseases.

Quite a large insect of dark color. The head is hemispherical, with large compound eyes on the sides, short three-segmented joints and oral apparatus in front. On the paws there are claws and sticky blades that allow the fly to move on any plane. One pair of wings. The fourth longitudinal vein of the wings (medial) forms a fracture characteristic of the species. The proboscis, torso and legs are covered with bristles, to which dirt easily adheres.

The oral apparatus is licking-sucking. The lower lip is turned into a proboscis, at the end of which there are two sucking lobules, between them is located mouth opening. The upper jaws and the first pair of lower jaws are atrophied. The upper lip and tongue are located on the anterior wall of the proboscis. Fly saliva contains enzymes that dissolve solids. After the food is liquefied, the fly licks it off. The fly feeds on human food, various organic substances. A satiated fly regurgitates the contents of the stomach and defecates every 5-15 minutes, leaving its secretions on food, dishes and various objects.

Flies lay eggs. One clutch contains up to 100-150 eggs. The transformation is complete. Can reproduce under favorable conditions all year round. 4-8 days after mating, females lay their eggs in rotting substances of plant or animal origin. In urban-type settlements, these are accumulations of food waste in garbage dumps, landfills, landfills, waste Food Industry. IN countryside breeding sites are accumulations of domestic animal manure, human feces, human feces on the soil. When laying eggs, the fly sits on sewage, after which it returns to the human dwelling again, bringing sewage on its paws.

A jointed worm-like larva emerges from the egg white color without legs and separate head. The larva feeds on liquid food, mainly decaying organic matter. The larvae are hygrophilous and thermophilic, optimum temperature for development 35-45 °C, humidity - 46-84%. Such conditions are created in manure heaps, since feces contain a lot of protein substances, during the decay of which a large amount of energy is released and at the same time high humidity is created. Larvae pass 3 larval stages. The larva of the third stage before pupation burrows into the ground. The chitinous cover exfoliating from her body hardens and forms a false cocoon.

The pupa is immobile, covered with a thick cuticle on the outside. Brown(puparium). At the end of metamorphosis, the fly (imago) emerging from the puparium passes through a rather thick layer of soil. Life expectancy is about 1 month. During this time, the female lays eggs 5-6 times.

medical significance. The housefly is a mechanical carrier primarily of intestinal infections - cholera, dysentery, typhoid fever, etc. The spread of this particular group of diseases is determined by the fact that flies feed on infected feces and swallow pathogens of intestinal infections or pollute the surface of the body with them, after which they transfer them to food human nutrition. With food, the pathogen enters the human intestine, where it finds favorable conditions. In the excrement of flies, the bacteria remain alive for a day or more. In addition to intestinal diseases, the housefly can carry pathogens of other diseases, such as diphtheria, tuberculosis, etc., as well as helminth eggs and protozoan cysts.

• House fly (Muscina stabulans). Distributed everywhere.

The body is colored brown, legs and palps are yellow. Coprophage. It feeds on feces and human food. The main breeding sites are human feces in non-sewered latrines and on the soil. In addition, it can develop in the faeces of pets and food waste. Adult flies live in yard latrines.

medical significance. Mechanical carrier of intestinal diseases.

The fight against flies should include: a) the destruction of larvae in the breeding grounds of flies; b) the extermination of winged flies; c) protection against flies of premises and foodstuffs.

The fight against flies in their breeding areas consists in the frequent cleaning of slop pits, latrines and garbage dumps. Dry waste should be incinerated. Waste must be composted or disinfected with disinfectants. In open latrines, faeces must be covered with quicklime or bleach. To exterminate winged insects, the premises are treated with DDT, hexachloran or other means; catch flies with sticky paper and flycatchers. The complete extermination of flies is necessary in public catering establishments, in food warehouses and shops, in hospitals and hostels. Open windows in the summer are hung with gauze or metal mesh. Products are stored in cabinets or in sealed containers.

A large fly, light gray in color, with black round spots on the abdomen. It lives in the fields and feeds on plant nectar. After mating, the flies give birth to live larvae. Attracted by the smell of decaying tissues (wounds, purulent discharge), the fly sprays larvae on the fly, attaching them to animal or human tissues, or, on occasion, to the eyes, nose, and ears of sleeping people. The larvae go deep into the tissues, make passages in them and eat away the tissues down to the bones. Before pupation, the larvae leave the host and go into the soil. For one laying, the fly hatches up to 120 larvae.

medical significance. Volfartiosis belongs to the group of so-called malignant myiasis. Flies lay their larvae mainly on people who sleep during the day in the open air or who are in a sick state. Female flies spawn from 120 to 160 very mobile larvae about 1 mm long into open cavities (nose, eyes, ears), on wounds and ulcers on the body of animals, sometimes humans (while sleeping in the open). The larvae crawls deep into the auditory canal, from where it makes its way into the nose, into the cavity of the upper jaw and the frontal sinus. During development, the larvae migrate, destroying tissues with the help of digestive enzymes and mouth hooks. The larvae eat away living tissue, destroy blood vessels. The tissues become inflamed; suppuration appears in them, gangrene develops. IN severe cases complete destruction of the soft tissues of the orbit, soft tissues of the head, etc. is possible. There are known cases of myiasis with a fatal outcome.

• Tse-tse flies- belong to the genus Glossina, carry African trypanosomiasis. Distributed only in certain areas of the African continent.

  . It has large dimensions - from 6.5 to 13.5 mm (including the length of the proboscis). Distinctive features are a protruding strongly chitinous proboscis, dark spots on the dorsal side of the abdomen, and the nature of folding wings at rest.

  Females are viviparous, laying only one larva, already able to pupate. Throughout her life (3-6 months), the female lays 6-12 larvae. The larvae are deposited directly on the surface of the soil, into which they immediately drill into and turn into pupae. After 3-4 weeks, the imaginal form comes out.

  They feed on the blood of wild and domestic animals, as well as humans. Moist and shade loving.

  • Glossina palpalis

    Geographic distribution. Western regions of the African continent.

    Morphophysiological characteristics. A large insect, more than 1 cm in size. The color is dark brown. On the dorsal side of the abdomen there are several narrow transverse yellow stripes and one longitudinal in the middle. Two large dark spots are located between the transverse stripes.

    It lives near human dwellings along the banks of rivers and lakes overgrown with shrubs and trees, as well as on forest roads in places with high soil moisture. It feeds mainly on human blood, preferring it to the blood of any animals, so humans serve as the main reservoir of trypanosomiasis transmitted by the fly. Sometimes attacks wild animals, as well as domestic (pigs). It only bites a moving person or animal.

    Morphophysiological characteristics. Dimensions less than 10 mm. The color is straw yellow. The transverse stripes on the dorsal side of the abdomen are wide, very light, almost white in color. Small dark spots. Less shade and moisture-loving. It lives in savannahs and savannah forests. It prefers to feed on the blood of wild animals - large ungulates (antelopes, buffaloes, rhinos, etc.). It rarely attacks a person, only during stops, usually on a hunt, when moving in the outback.

    Control measures. In order to destroy the larvae, shrubs and trees are cut down in the breeding areas (in the coastal zone, around settlements, at river crossings, at water intake points and along roads). Insecticides and traps are used to kill adult flies. For the purpose of prevention, wild animals are exterminated, which serve as a source of food for flies (antelopes, buffaloes, rhinos, hypopotamuses); use introduction healthy people drugs for sleeping sickness. The drug, introduced into the body, circulates in the blood and prevents a person from infection. According to WHO, mass injections to the population in some African countries have led to a significant decrease in the incidence.

Common and malarial mosquitoes

The mosquito (Culex) belongs to the Diptera order and is a member of the large mosquito family (Cullcidae).
This is a well-known small insect (6-7 mm) with a prominent chest, a long narrow abdomen and one pair of narrow wings. The male is easily distinguished from the female by the more developed, strongly feathery antennae. Only females attack people and animals and feed on their blood, in which the proboscis has piercing bristles. Males feed on plant sap.

As an excursion object of great interest are larvae mosquitoes, which in spring are found in masses in shallow fresh waters, most often stagnant, moreover, where the bottom depth is not more than 1-1.5 m: in ponds, ditches, forest puddles, pits with water, often even in uncovered gutter tubs, vats and so on.

The mosquito larva looks like a legless worm with an expanded chest, a jointed abdomen and a large head, on which two black eyes are easily distinguished. On the penultimate segment of the abdomen, a long, oblique outgrowth process is seen, this is a respiratory tube, at the end of which there are respiratory openings.

Mosquito larvae. Increased 1 - larva of common mosquito (Culex pipiens); 2 - larva of the malarial mosquito (Anopheles maculipennis); 3 - larva of an amphibian mosquito (Dixa amphibia); gg - respiratory openings from which two tracheal trunks begin.

It is not difficult to detect the presence of larvae in this pool, since the larvae in a calm state hang at the very surface of the water. To catch them, you need to quickly draw a net through the water before the nimble society has time to sink to the bottom. Where there are many larvae, it is easy to do without a net, simply scooping up water with some kind of vessel. To examine the caught larvae, they should be placed in a small glass jar or a wide test tube filled with clean water.
The attention of tourists first of all stops at the characteristic movements larvae. It is enough to throw some object into the water, wave something over the water, or even quickly approach the reservoir where the larvae are located, as they immediately break away from the spot, sink down with characteristic snake-like movements and hide at the bottom of the reservoirs. Their movement in the water is helped by swimming hairs, which sit in bunches on the segments of the body. In particular, a large tuft is present on the last caudal segment. After some time, the larvae again float to the surface of the reservoir, where they are driven by the need for air.
The point is that the larvae breathe atmospheric air, the supply of which in the body requires constant refreshment. Larvae, rising to the surface, expose their caudal windpipes from the water and take in air into the tracheal trunks. In this case, the larva hangs at the surface of the water upside down, in a very characteristic position, at a certain angle to the surface of the water (40°-60°). It is retained by the surface tension of the liquid, which forms an elastic film, which the larva pierces with its respiratory process and to which it hangs from below.
The mass of larvae hanging in this way, dotting the surface of the reservoir, is sometimes a remarkable sight.
As soon as the larva breaks away from the surface tension film, it begins to sink into the water, since its body is heavier than water. To float to the surface, she needs to resort to active swimming movements.
feed on larvae by various microscopic organisms, for example, unicellular algae, and also, in all likelihood, parts of rotting plants.
Development The larva consists in a series of successive molts (a total of 3 molts are observed), and then the larva turns into a pupa, which is completely different in its warehouse from the larva. She somewhat resembles in appearance a small tadpole, and the front part of her body is dressed common shell, and only the jointed abdomen remains free. The whole body is curved like a comma. In water, the pupa assumes a different position than the larva. Suspended to the surface, it puts out of the water not the rear, but the front end of its body. On the dorsal side of the front of the body, it has a pair of funnel-shaped breathing tubes that are visible to the naked eye and resemble small horns, giving the animal a very peculiar appearance. These horns are chrysalis and protrude from the water when breathing. When frightened, the pupae, like the larvae, dive into the water, but move differently: hitting the water with their abdomen, which ends in fins, they amusingly somersault over their heads; after holding out for some time at the bottom, the pupae again emerge, holding their horns up and passively rising to the surface, since their body is lighter than water, having an extensive air chamber inside.
The pupa does not take any food. At the end of a short life, the color of the pupa changes: the older the pupa, the darker it is. Before hatching, it turns from light brown to almost black.
A mature pupa bursts on the surface of the water, and a young mosquito gradually crawls out through the gap between its horns. An abandoned pupal shell floating on the surface of the water serves as a temporary boat for him, by the edges of which he clings until his wings spread and dry, and he takes off into the air. The slightest disturbance on the surface of the water at this time is detrimental to the mosquito, as it falls into the water, from where it is no longer able to get out.
Some time after fledging, having fed on blood, the females begin to lay eggs, which are released directly onto the surface of the water. These floating egg packs consist of several hundred eggs and have a very distinctive oval shape with a spoon-shaped indentation that allows them to float on the surface of the water like a tiny shuttle. At the same time, individual eggs, having an oblong cigar-shaped shape and glued into a common pack, stand perpendicular to the surface of the water.
Usual duration development an ordinary mosquito (at a temperature of 15-20 °) - about a month, and in the pupal stage the insect lives on average about 2-5 days. The duration of development is directly related to the temperature of the water and at a higher temperature it is almost halved. On the other hand, at temperatures below 12° the development of the larvae stops altogether. On an excursion, this dependence can be shown by fishing in parallel in two adjacent reservoirs, one of which is in the sun and the other in the shade (for example, under the shade of trees). While in the second reservoir we will find only young larvae, in the first reservoir most of the larvae have not only reached their maximum growth, but have already managed to turn into pupae.

Among other representatives of the mosquito family, the larvae of which are often found in our fresh water bodies, we note the following forms:

Amphibious mosquito(Dixa amphibia). The larvae of this mosquito are very similar to the larvae of the malarial mosquito, but they hold themselves in a completely different way. Curving its body in a steep arc, the larva of the amphibian mosquito catches on any objects protruding from the water so that the front and rear ends of its body remain immersed in water, and the middle part of the body is kept out of the water. Such a semi-terrestrial way of life of this larva was the reason for its name. Its pupa, living in water, exists for a very short time, only a few hours, and quickly passes to fledging. An adult insect lays eggs, enclosing them in a gelatinous lump, which sinks to the bottom of the reservoir.

Mosquito larvae. Increased 1 - larva of the coretra, or pinnate mosquito (Corethra plumicornis): M - air sacs; 2 - mochlonyx larva, or mosquito-shaped mosquito (Mochlonyx culiclformis).

Cirrus mosquito Choaborus (Corethra) plumicornis L. has a very interesting vitreous-transparent larva, which can be seen in the water only with a certain attention. This transparency helps the larva to elude its many enemies, in particular fish. Unlike other mosquitoes, the coretra larva never rises to the surface of the water, but constantly stays at some depth in a horizontal position; most of all, it hangs motionless in the water, from time to time making sharp jumps and bending the body at the same time. The coretra larva does not possess any respiratory adaptations, but absorbs oxygen dissolved in water through its racing skin.
It feeds on various microscopic animals, most often small crustaceans, which it catches extremely cleverly, grabbing prey with its hook-shaped curved oral appendages.
The best way to examine a coretra caught on an excursion is to put it in a small vessel with clean water and look at the larva in the light. Due to the transparency of the cover, you can even see with the naked eye many features of its internal structure.
Two pairs of silvery bubbles immediately catch your eye - one in the front, the other in the back of the body - which are filled with air and serve as a swimming device for the larva, supporting it in the water. The intestinal canal is also visible, along its entire length, and even the tracheal trunks passing along the body. This larva presents a particularly remarkable picture when examined under a microscope or with a strong magnifying glass, which can be done when examining the material of an excursion.
When mature, the larva turns into a pupa, in general very similar to the pupa of an ordinary mosquito, but never showing itself on the surface of the water.
Adult insects lay their eggs in water, enclosing them in a gelatinous shell. Such a clutch looks like a small transparent ball, which contains oblong eggs (100 - 150 pieces), arranged in a tight spiral.
Adult insects are gray-brown in color (length about 6 mm). The males have long, fluffy, yellowish coats, from which the mosquito gets its name. Unlike the common and malarial mosquito, they do not have the ability to bite people and animals, without having piercing bristles in their proboscis.
Resembling some features of its structure, the larva of an ordinary mosquito, and others - the larva of the coretra, and is, as it were, a transitional form between them (Fig. 259). Like the larva of the common mosquito, the Mochlonix larva has a windpipe and an expanded thoracic part of the body. Like the larva of the coretra, it has two pairs of swimming air bladders and stays at a certain depth in a horizontal position, remaining for a long time motionless in the water. The larva is equipped with grasping antennae and feeds mainly on small crustaceans. It is found, usually in the same reservoirs in which we find the offspring of the common mosquito.

Mosquito larvae and pupae. Increased (According to Porchinsky.) On the left - common mosquito; on the right is a malarial mosquito.

Heads of female common mosquitoes (Culex) - on the left. Gone strongly. (According to E. N. Pavlovsky.) 1 - antennae; 2 - tentacles; 3 - proboscis and malarial mosquito (Anopheles maculipennis) - on the right. Gone strongly. (According to E. N. Pavlovsky.) 1 - antennae; 2 - tentacles; 3 - proboscis.

1. The malarial mosquito has longer legs than the common mosquito.
2. The female malarial mosquito has jointed tentacles on its head, which are almost equal in length to the proboscis, while the female common mosquito has very short tentacles, not exceeding a quarter of the length of the proboscis (do not mix the tentacles with the screeds (antennae), which are the same in both species). length).
3. The malarial mosquito has dark spots on its wings, while many representatives of the genus Culex (C. pipiens) do not have them.
4. At rest, the perched malarial mosquito holds its body more or less perpendicular to the surface on which it sits, while the common mosquito holds its body more or less parallel to the substrate.
5. The larvae of the malarial mosquito differ from the larvae of the common mosquito in that they do not have a long respiratory tube at the end of the body, and the respiratory openings are sessile in them. Being on the surface of the water, they do not hold at an angle to the surface, like the larva of an ordinary mosquito, but lie horizontally.
6. Malarial mosquito larvae live in clean water and do not settle in water bodies rich in organic residues, while common mosquito larvae are often found in such water bodies.

Reservoirs heavily overgrown with high marsh vegetation (reeds), as well as waters completely covered with a green cover of duckweed, are not very suitable for the breeding of larvae. In addition, the larvae are very sensitive to water reactions and do not occur in acidic waters, preferring neutral or slightly alkaline ones. For this reason, the water of peat bogs, rich in humic acids, is free from Anopheles larvae. Water bodies poor in flora and fauna are also usually not populated by malarial larvae.
Especially often you can find the larvae of the malarial mosquito where there is an accumulation of various filamentous algae in the water, among the thickets of which they successfully hide. For these reasons, the larvae of the malarial mosquito are much more difficult to detect than the larvae of the common mosquito, and their finding requires a more or less thorough survey of the reservoir /
The disturbed larva dives and sinks to the bottom, where it can stay for quite a long time, but then again rises to the surface, as it breathes atmospheric air.
The larvae feed on small aquatic organisms, which are captured by the movement of the mouth brushes and carried into the mouth opening. Sometimes the larvae feed on plant food nibbling on filamentous algae, etc.

Wings of malarial mosquitoes. Gone strongly. (According to E. N. Pavlovsky.) 1 - common malarial mosquito (Anopheles maculipennis); 2 - forest (Anopheles bifurcatus); 3 - Pallas mosquito (Anopheles hyrcanus).

The body of the larva consists of a head, thorax and abdomen. On the abdomen, 9 segments covered with setae can be distinguished. The last segment bears a bundle of long setae, the so-called oar. In addition, on the last segment, 4 thin leaf-shaped appendages, called anal gills, can be distinguished (Fig. 266). The size of the larvae increases with age from 1 to 8-9 mm. There are four instars of larvae, and the color of the larvae sometimes changes with age. The larvae of the first age are black, the second and third instars are black or grayish, the larvae of the fourth age usually lighten and are greenish or reddish, but sometimes retain a dark color.
The larvae develop faster, the higher the water temperature. At 20-25°C, development ends in 3-4 weeks, at a temperature of 25-30°C, 8-10 days are enough for this. During the summer in the south of the USSR 4-5 or more generations of anopheles are hatched. In the northern parts of the Union at the latitude of Leningrad, 2-3 generations take wings.
The enemies of the larvae of the malarial mosquito are many small aquatic predators: larvae of dragonflies, water beetles, water bugs, as well as some types of fish (carps, perches). A small, very voracious and hardy viviparous fish gambusia (Gambusia affinis) imported from South America, which has been acclimatized in the USSR since 1924 (on the Black Sea coast of the Caucasus), plays a special role in the extermination of Anopheles larvae.
The pupa of the malarial mosquito is very similar to the pupa of the common mosquito, only it is more curved and has shorter respiratory horns.

The eggs of the malarial mosquito are never connected in large shuttle-shaped packages, but float on the surface of the water in small piles, several pieces together. At the same time, the eggs are not glued together in packs, but lie on the water with their long side.
Adult malarial mosquitoes usually stay close to the breeding grounds and do not fly far. It is believed that they rarely fly further than 1-2 km. In the vertical direction, mosquitoes rise no higher than 15-20 m. In their way of life, these are completely nocturnal animals. During the day, they hide in dark places, climb into barns, latrines, where they sit motionless on walls or ceilings. At night, they fly away and at dawn again climb into their shelters, where they are easy to find and catch, since during the day they are in a lethargic, passive state. Therefore, malarial mosquitoes very rarely attack a person during the day, and most often bite sleeping ones.

Mosquito larvae.
Left - malarial mosquito (Anopheles); on the right - an ordinary mosquito (Aedes cinereue); 1 - tentacles; 2 - rosettes of abdominal hairs; 3 - spiracles; 4 - antennae; 5 - 9 abdominal segment; 6 - brush; 7 - head; 8 - chest; 9 - abdomen (I-VIII segments of the abdomen); 10 - scallop of spines; 11 - respiratory siphon; 12 - spiracles; 13 - anal gills.

Adult males and females feed differently. Males take exclusively plant food, feeding on plant juices. Females also feed on plant foods for a long time, but during the breeding season they need the blood of animals as a nutrient material for the formation of eggs. Having sucked blood, the female digests it for about 2 days and again looks for food.
The life span of males and females is not the same. Males live only a few days and therefore are rare, females are up to two months (not counting the wintering time). By autumn, males and unfertilized females die. Fertilized females that have not yet laid eggs remain for the winter. They hibernate in rooms sheltered from the wind and sharp fluctuations in temperature (cellars, basements, etc.), where they climb into dark corners (often onto cobwebs) and fall into a numb state. A gradual decrease in temperature to - 30 ° C is tolerated by mosquitoes without harm to themselves. In the spring, overwintered females fly out when the average daily air temperature reaches 5-7 ° and the sun begins to warm the reservoirs sufficiently. 10-15 days after departure from wintering, females start laying eggs for the first time.

Females lay their eggs in water when it warms up to a temperature of 10-11 ° C. Egg laying in water bodies occurs several times, and one female can lay up to 200 eggs at a time.

Pupa of a common mosquito. Gone strongly. (According to E. N. Pavlovsky.) Pupa and breathing tube.

In the European part of Russia, the following types of malarial mosquitoes are found:
Anopheles vulgaris(Anopheles maculipennis Meig.) - the most common species, which is the only one and is found in the northern parts of Russia and is the main vector of malaria. The color of the mosquito is brown-brown with two blackish stripes on the sides of the middle back. There are four spots on the wings of clusters of black-brown scales arranged in the form of a Roman numeral V. Length 6-10 mm.
Anopheles forest(A. bifurcatus L.). Color black-brown. Wings without dark spots. Length 6-8 mm. Found in forests. Less likely to attack a person than the previous species. It occurs in the forest region of Russia, in the forest-steppe Ukraine, in the Crimea, in the Caucasus.
Anopheles blackfoot(A. plumbeus Steph.). The color is blackish gray with a leaden tinge. Wings without spots. Legs are black. The size is less than the previous ones, 4-5 mm long. Forest view. Lays eggs in tree hollows filled with water. It is found in the forest-steppe Ukraine, in the Crimea, in the Caucasus.
Anopheles Pallas(A. hyrcanus Pallas). Dark in color with a predominance of dark coloration on the wings. Tarsi with white rings at the top of the first 3-4 segments. Length 5-6 mm. It is found in vast swamps and floodplain meadows. It is found in the south (southern Ukraine, the Lower Volga region, Crimea, the Caucasus).
In addition to these species, there are several more found only in Transcaucasia, Turkestan.
In the most common species Anopheles maculipennis, several (4-5) forms are currently distinguished, so that they can only be sorted out by the microscopic features of the eggs (color, size of the swimming chambers).

Anopheles is commonly known as a species of malarial mosquito because it is considered the primary vector of the disease. It is also the transmitter of heartworm in dogs.

Description

The Anopheles mosquito prefers to feed on mammals, including humans.
The body of an adult Anopheles mosquito is dark brown to black in color and has 3 sections, which are the head, chest and belly.

When resting, the stomach area of ​​the insect points upward, rather than parallel to the surface, as in most mosquitoes. Anopheles females breed several times during their short life, producing eggs after finding blood. Although they live only from a few weeks to a month, they produce thousands of eggs during this time.

The female mosquito lays up to 200 eggs on the surface of the water. Each of the single eggs stays on the water with the help of floats. They need two days to three weeks to hatch, depending on the temperature. environment.

Mosquito larvae are called wigglers, as they move in a peculiar way. They lie parallel to the surface of the water to feed on fungi, bacteria, and other tiny organisms. The larvae go through four stages, after which they become pupae.
The pupae are known as tumblers. The pupae come to the surface of the water to breathe through tiny "tubes" and do not eat for 1-2 days until they become adults.

breeding habit.

Anopheles mosquitoes lay their eggs in the most different places. The breeding grounds for malaria mosquitoes are freshwater or salty water. Ground pools, small streams, irrigated lands, freshwater swamps, forest pools, any other place with clear, slow moving water are considered prime breeding grounds for malaria mosquitoes.

Females, especially fertilized ones, survive the winter dormant in caves, which means the breeding cycle can continue all year round. Eggs are able to withstand cold temperatures; however, freezing usually kills them.

To learn more Why do mosquitoes dream

Geography

Where do malaria mosquitoes live? Anopheles live almost anywhere in the world, with the exception of Antarctica. They are found in areas where malaria has been eradicated, so there is always the possibility that they can re-infect that area.

All that is needed is blood from a human or mammal infected with malaria in order for them to be able to pass it on to another human or mammal. The person who initially became infected may have just traveled to an area where malaria is present, or it may be an unsuspecting visitor to an endemic region who brought the disease.

As world tourism is prevalent today, the possibility of recontamination of a previously clean area always exists. In addition, regions that have never experienced outbreaks may become endemic for the first time. Where do malaria mosquitoes live? Anywhere. Effective mosquito control systems can provide protection against these pests and the diseases they transmit.

• There are about 430 species of Anopheles mosquitoes, but only 30 to 40 species of mosquitoes carry malaria.
• Many species of Anopheles mosquitoes have become resistant to insecticides through years of pesticide use.
• The Anopheles malaria mosquito is most active twice: just before dawn and just after dark. At this time of day, outdoor mosquito control is essential to provide protection from the bite.
• The Anopheles mosquito causes an outbreak of "airport malaria" when it is accidentally imported via luggage or aircraft.
• Sir Ronald Ross, who proved the transmission of malaria by the Anopheles mosquito, was not only a scientist; also mathematician, writer, poet, editor, composer, artist.

The Anopheles mosquito is still found in many areas where malaria has been eradicated. Although the parasite has been eradicated, it is still present, and it is possible for malaria to recur after a single bite from a malaria mosquito.

Many people have been afraid of malarial mosquitoes since childhood, knowing that they are carriers of the causative agent of an extremely dangerous disease - malaria. These fears are not without merit. Learn more about how the Anopheles mosquito differs from other harmless species of such insects - this information will help prevent serious risks to your health.

What does a malaria mosquito look like?

Insects that are classified as belonging to this species are often referred to by biologists as anopheles (short for Latin name Anopheles maculipennis). These Diptera appearance not much different from ordinary mosquitoes. Anopheles has a small body (6-10 mm), a small head and long legs. On transparent scaly porches, such insects have dark spots, which is not the case with ordinary mosquitoes. Their jaw system consists of a lower lip (with the help of jaw-nail files on it, anopheles cuts through the skin) and a proboscis (its mosquito pushes it into the slot and sucks blood).

Where does it live

These insects, which for humans are a source of infection with a deadly infection, are distributed almost all over the world. The geography of regions where the malarial mosquito lives includes all areas where there is no harsh winters(with prolonged cold weather, the cycle of development of anopheles is interrupted). In the world, these carriers of infection are very widespread in areas with a hot climate.

So, on the islands close to the equator, in the countries of Africa, Central and South America, and South-East Asia About a million people die every year due to malaria through the bites of Anopheles mosquitoes. In Russia, these insects, although they are found in the European part of the country and in Western Siberia but here they are not so dangerous. In this area, the ambient temperature does not contribute to their rapid reproduction, and there are no carriers of malaria in this area.

How is it different from the usual

Insect carriers of the infectious agent have some structural features of the body. A very noticeable difference between a malarial mosquito and an ordinary mosquito is that it has long hind legs. This characteristic outward sign can be clearly seen in the photo of the insect. Due to this structural feature, the back of the body of a sitting anopheles is always at a large angle to the surface, and the body of an ordinary mosquito is always parallel to the surface on which it is located.

Another important difference observed in the structure of females. Jointed tentacles located on the head of the female Anopheles, almost the same length as the proboscis. In ordinary mosquitoes, such tentacles are noticeably shorter - no longer than ¼ of the proboscis. You can also distinguish between these two types of insects by the dark spots on the wings, which are present in malaria vectors and are absent in ordinary individuals. Another striking feature of anopheles is that they do not immediately sit on the skin of the victim, but before the attack they seem to dance in the air.

Types of malarial mosquitoes

In practice, this variety of mosquitoes includes all Diptera of the genus Anopheles, of which there are more than 460 species in the world today. It is important to know that only about 100 species of these insects can actually carry malaria. IN different regions epidemiological danger is different types anopheles. Interesting fact: many people believe that the centipede mosquito, an insect that is distinguished by its large sizes. The facts show that such Diptera are harmless, because their food is nectar, or they may not eat at all.

What is dangerous

Only female Anopheles pose a threat to human health. Male mosquitoes live only a few days and feed only on plant juices. Females of these insects can live up to two months. They also feed on plant foods, but during the breeding season they need the blood of animals as a source of protein for the formation of their eggs. Having received such food, the female processes it for about two days and again looks for a new victim of the attack.

What happens if you get bitten by a malarial mosquito

You need to know that the bites of such insects do not in all cases pose a real danger. Infection will only occur if a female malarial mosquito has previously bitten a person with malaria. Only after contact with blood, in which Plasmodium already lives, does the insect become infectious. The ability to infect the offspring of this female also will not be transmitted.

Scheme of transmission of the causative agent of malaria to humans

What does a bite look like

By the appearance of the skin, it is problematic to determine which insect has bitten a person - an ordinary mosquito or anopheles. The bite of a malarial mosquito is also itchy, redness and slight swelling may appear on the skin. Often, the patient learns that infection with malarial plasmodium has occurred after the end of the incubation period. He begins to show the characteristic severe symptoms of the disease: chills, fever, headaches, rapid pulse and even convulsions.

How to protect yourself from the malaria mosquito

What precautions should be taken to prevent the risk of contracting a serious illness? Due to the fact that Anopheles lay their eggs in water bodies and here in the summer new insects appear from the larvae, high risk bite occurs, for example, while resting near the water. In order to prevent infection when staying in nature, it is recommended to use different means of protection against mosquitoes. So, repellents will repel dipterans well, and mosquito nets will not let into the tent not only large insects (such as the centipede mosquito or anopheles), but also other midges.

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Attention! The information presented in the article is for informational purposes only. The materials of the article do not call for self-treatment. Only a qualified doctor can make a diagnosis and give recommendations for treatment based on the individual characteristics of a particular patient.