Malaria mosquito: what happens if it bites. Ordinary and malarial mosquitoes Representative of the genus Anopheles causes biology

11.06.2019

In appearance and lifestyle, the malarial mosquito differs little from the common one. These insects got their name for the ability to carry the causative agent of malaria from person to person.

Malaria mosquitoes are different from normal mosquitoes appearance and behavior during the bite

Looks normal and malarial mosquitoes almost the same, although there are several external differences. The main differences between adults are as follows:

The malarial mosquito has legs (especially the hind legs) that are much longer than those of the common mosquito.
In the female malarial mosquito, the jointed tentacles located on the head are almost the same length as the proboscis. In ordinary ones, the tentacles are short and do not exceed 1/4 of the length of the proboscis (not to be confused with antennae).
Anopheles mosquitoes have dark spots on their wings, while they are absent in most species of common mosquitoes.
In a sitting malarial mosquito, the body is located at a large angle to the surface, it strongly raises the back. An ordinary mosquito has a body almost parallel to the plane on which it sits.
Another feature of this type of insect is that before the attack (landing on the skin of the victim), they seem to dance in the air.

Adults of the malarial mosquito at first glance look the same as individuals of other species, but it is worth learning to distinguish them

Mosquitoes cannot live without water bodies. They lay eggs in the water, where their larvae grow and develop, up to the appearance of a young insect. The malarial mosquito is more picky about its breeding site. It does not lay eggs in water bodies heavily overgrown with reeds and cattails, covered with duckweed. Water should be neutral or slightly alkaline. You will not see this type of mosquitoes on reservoirs with "sour" waters. Therefore, you will not find Anopheles larvae in the swamps, while common mosquitoes suits almost any body of water.

The malarial mosquito grows its offspring in clean water bodies where there are accumulations of filamentous algae. Its larvae successfully hide among these algae from predators. If the mosquito larvae are disturbed, they quickly sink to the bottom, where they can stay for a long time. Outwardly, mosquito larvae also differ. At the larva common mosquito at the tip of the body there is a long breathing tube, which the malarial does not have. Its role is performed by breathing holes at the end of the body. Larval development lasts from one to four weeks, depending on external conditions, the main of which is the temperature of the water - the higher it is, the faster the development occurs.

Only female mosquitoes drink human blood, since protein is necessary for the development of eggs.

After the birth of young mosquitoes, the process of swarming and mating takes place. It should be noted that the male mosquitoes that hover over the paths and reservoirs are vegetarians, they feed exclusively on the nectar of flowers and the juice of plants. In females, the need for bloodsucking arises after fertilization - protein is necessary for the development of eggs. A hungry female mosquito has an exceptional sense of smell, she is able to sense and determine the location of a person or a warm-blooded animal at a distance of up to three kilometers. In one bite, an insect is able to absorb an amount of blood that exceeds its weight. After that, from 150 to 200 eggs develop in the body, which the female lays in a chosen reservoir. Within two days after laying, the female does not show aggressiveness and feeds on plant sap. Then everything repeats: mating, searching for a “victim” for a new portion of blood, another laying of eggs. Females live for about two months, males - only a few days.

The bite of malarial mosquitoes becomes dangerous only if they have bitten a person with malaria. From this moment on, the female mosquito becomes a carrier of the disease - Plasmodium teems in her saliva, disease-causing. Reproduction of malarial mosquitoes does not affect the number of malaria vectors, since the ability to infect is not transmitted to offspring.

Going out into nature, especially in southern countries ah, be sure to equip the tent with mosquito nets and use repellents

Anopheles mosquitoes are nocturnal insects, during the day they hide in secluded places. Therefore, the vast majority of attacks occur at night on sleeping people and animals. Therefore, when going on vacation to nature or fishing, it is necessary to take measures to protect against the bites of malarial mosquitoes, which live in almost the entire territory of the Russian Federation, except for the far north.

The same measures will come in handy when going on vacation to southern countries, where there is a real danger of contracting malaria.

Entrances to tents and windows must be covered with mosquito nets treated special formulations repelling insects.
You can use anti-mosquito coils and other sources of vapors and gases that are poisonous to insects.
Creams, ointments, lotions and emulsions with insect repellants applied to the skin will protect against bites for 2-5 hours.
With the approach of the dark time of the day, it is necessary to wear clothes that cover all parts of the body as much as possible, and those that are not closed should be treated with repellents.

It should be noted that in everyday life they are often confused, calling large centipede mosquitoes malarial. This is not true, since the weevils feed on plant sap and are completely safe for humans.

Malaria is one of the most widespread diseases in the world. About 1 million people die from it every year in the world. The main areas of distribution of malaria are hot tropical countries: Africa, Central and South America, countries South-East Asia, Papua New Guinea and others.

To general note, the distribution area of these dangerous insects very extensive. They are found almost everywhere, including on the territory of our vast Russia. Only people living in the most northern regions and on the territory Eastern Siberia. Well, mosquitoes do not like very low temperatures, real Siberian winters are very severe for them.

It may sound a little ridiculous, but malarial mosquitoes for the most part are found where there are foci of malaria. In other areas, meeting with them is very rare. By themselves, these mosquitoes are not dangerous until they have tasted the blood of a person with malaria.

How do they differ from our usual “brothers and sisters by blood” and how to protect ourselves from this disease, we will now find out.

I propose not to beat around the bush and immediately begin to consider the main features that distinguish the common mosquito from the malarial one.

First, the malarial mosquito is easily identified by its long hind legs. BUT! It should not be confused with large centipede mosquitoes, which are kind-hearted creatures and feed exclusively on plant juices. For humans, they are completely harmless.

Secondly, during landing on the surface, his body is located at a large angle to it, almost perpendicular, and all “thanks” to the long hind legs. Our common mosquito behaves more modestly and tries not to stand out, placing its body almost parallel to the surface.

The wings of the malarial mosquito are decorated with small black spots - this is the third difference.

Fourthly, in female malarial mosquitoes, jointed tentacles are located on the head, equal in length to the proboscis. In female common mosquitoes, they are much shorter. But it is unlikely that you will peer into the head of a mosquito that has landed on your hand, so be guided by the more obvious and simple signs listed above.

The first is the environment. Mosquitoes dear to our hearts cannot live without water, because almost their entire life cycle is connected with it. Their childhood, adolescence and youth pass in a variety of water bodies, from ordinary puddles to large ponds :).

Reservoirs - habitat for mosquito larvae

Most often, the home for the larvae of the malarial mosquito is clean or sparsely overgrown water bodies that are not overgrown with duckweed and are suitable for larvae. They don't fit acidic waters and reservoirs, poor in flora and fauna (since there will be nothing to eat).

But they are abundant in neutral or slightly alkaline waters and where filamentous algae grow, which are an excellent refuge for larvae from fish and other aquatic predators who want to feast on them.

Malaria mosquito larva

Larvae of ordinary mosquitoes are not so fastidious and can live in reservoirs rich in organic residues and even in sewer waters (this applies to urban mosquitoes).

The second is the structure of mosquito larvae. The larvae of the malarial mosquito do not have a long breathing tube at the end of the body, its role is played by sessile breathing holes.

In addition, the larvae of the common mosquito are located at a large angle to the surface of the water, and the malarial mosquito takes an almost horizontal position. So they swim quietly and peacefully on the surface from 8 days to 4 weeks. It all depends on the temperature of the water, the higher it is, the faster the process of development of the larvae.

Out of about 150-350 eggs of a malaria mosquito (their number most often depends on how tightly mommy managed to dine), not everyone survives. Many of them act as excellent food for dragonfly larvae, water bugs and beetles, as well as carps, perches and some other fish. The female common mosquito lays 30 to 150 eggs.

After laying, the female turns into a vegetarian for 2 days and switches to vegetable juices. And then a new mating, a new "victim" and a new portion of eggs on the surface of the water.

The entire body of mosquito larvae (both malarial and common) is covered with many bristles. As they grow older, they grow from 1 mm to 8-9 mm and change their color at each stage of development. So at first they will be black, then slowly turn gray and in the end, before “hatching”, they become green or reddish, but sometimes they retain a dark color.

pupa of a malarial mosquito

Malaria mosquitoes lead night image life and in the daytime hide somewhere in dark secluded places. Therefore, most of their attacks occur at night, when a person is sleeping.

Blood drunk female

The menu for adult females, males and their larvae is completely different. The former prefer to drink blood, in addition to 2 days of vegetarianism after oviposition; the second - feed exclusively on plant juices, and still others - on small aquatic organisms, which are caught with mouth brushes and sent to the mouth opening. If filamentous algae are nearby, they will also feast on them.

Male drinking vegetable juice

Females live longer than males. Their lifespan can reach up to 2 months if they are not slammed earlier. Males live on the strength of a few days.

How to protect yourself from malaria:

1. Mosquito nets, curtains or mats treated with a special insecticide (this is if you are vacationing in a country where there is a risk of contracting malaria).

Mosquito nets

2. Use of mosquito coils and other fumigants (poisonous vapors or gases).

3. After dark, wear clothes that cover exposed areas of the body - long-sleeved shirts, pants, long skirts.

4. Reducing the number of larvae of mosquito mosquitoes:

- using kerosene or fuel oil. If you pour them a little into a stagnant pond with mosquito larvae, then a thin film forms on the surface of the water, which prevents the larvae from breathing. After 2 days they die;

- settlement of reservoirs with fish fry that feed on mosquito larvae. Most often these are representatives of the carp family.

Mosquitoes of this genus are found everywhere except Antarctica. However, only in endemic areas is it possible for malaria to be transmitted by mosquitoes of different species. A persistent mosquito population and the continuing possibility of mosquito infection with malaria plasmodia poses a risk of repeated outbreaks of malaria in humans.

Mosquito development.

Evolution occurs in four stages: egg, larva, pupa, and adult. The first three stages take place in water and the adult insect lives for 5-14 days, depending on the species and ambient temperature.

Adult females lay 50-200 eggs. Eggs are laid in water, are not resistant to desiccation and open within 2-3 days, when adverse conditions may exist until the next stage up to 2-3 weeks.

mosquito larvae genus Anopheles are not adapted to breathing in water and therefore are located near the surface, they breathe through spiracles located in the 8th segment of the abdomen.

The larvae feed on algae, bacteria and other microorganisms and swim in jerky movements. Larvae also develop in 4 stages, the change of stages is accompanied by a change in the outer chitinous shell - molting. Mosquitoes need fresh water to develop. clean water- swamps, mangrove swamps, rice fields, grassy ditches, banks of streams and rivers, temporary rainwater reservoirs, possibly in pools and even in leaf axils filled with water.

The mosquito pupa is shaped like a comma, and is also located near the surface of the water for breathing. The duration of evolution from an egg to an adult mosquito depends on the species and habitat conditions, averaging 10-14 days in tropical conditions.

adult mosquitoes

Like all mosquitoes, adult anophelines have a head, thorax, and belly. On the head are eyes, sensory antennae, a proboscis for feeding. On the chest are 3 pairs of legs and a pair of wings. The stomach contains the digestive and reproductive organs. The abdomen can increase significantly in size as it fills with blood and the eggs mature. Blood is digested over time. Mosquitoes of the genus Anopheles can be distinguished by the palps located next to the proboscis, by the presence of a distinct pattern on the wings, as well as by their typical position before the bite. After transformation from a pupa, adults are not very active for several days, males gather in flocks to attract females for mating. Males live for about a week, feeding on plant nectar. Female individuals can also feed on nectar, but for the normal development of offspring they need to receive blood. After the bite, the females rest for several days, during which time the blood is digested and the eggs mature. Duration depends on external conditions, usually takes 2-3 days in tropical conditions. As soon as the eggs are fully mature, the female lays them in a pond, and again looks for an opportunity to feed on blood until she dies. The life span of the female reaches 1 month.

Factors associated with malaria transmission and malaria control

For the transmission and development of plasmodia in the body of a mosquito, a certain life span of the intermediate mosquito host is necessary. On average, it takes 10 to 21 days for Plasmodium to develop into a form that is infectious to humans. Therefore, reducing the life of a mosquito will lead to a decrease in human morbidity. This is facilitated by the use of insecticides.

Feeding factor of mosquitoes in the twilight (active at dusk or dawn), or nocturnal (active at night) period, the place of feeding and rest after feeding is outdoors (exophilic and exophagic) or indoors (endophilic and endophagic). Limiting the ability of the mosquito to bite at its convenient time and place through the use of mosquito nets and the construction of facilities with limited access will also lead to limiting the transmission of malaria from the mosquito to humans.

The factor in reducing the number of places for the development of the aquatic phase of the mosquito is the drainage of swamps, the distance from dwellings.

insecticide resistance

Resistance to chemicals can occur fairly quickly due to birth a large number generations during the year. There are over 125 mosquito species with resistance to one or more insecticides.

Modern developments.

Some species of Anopheles are able to independently eliminate plasmodia that have entered the body. These species are being carefully studied with the goal of introducing a similar mechanism to the entire mosquito population.

Species belonging to this family are distributed from the tundra zone to the desert oases.

They are small in size. On the head are large compound eyes, antennae and mouthparts. Only females with piercing-sucking mouthparts are blood-sucking. It consists of a lower lip in the form of a gutter, an upper lip in the form of a plate closing 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 upper and lower lip. The appendages of the lower jaws are the mandibular palpi. In males, the apparatus is sucking, the stabbing parts are reduced. Mosquitoes feed on the nectar of flowers. Antennae lie on the sides of the mouth apparatus, in males they are covered with long hairs, in females - short. The development of mosquitoes occurs with complete metamorphosis. Places of breeding, depending on the genus of mosquitoes, can be natural and artificial reservoirs. Mating takes place in the air ("dancing mosquitoes"). After fertilization, the female needs blood to develop the eggs. The process of digestion of food and maturation of eggs received the name gonotrophic cycle. With gonotrophic harmony, one portion of blood is enough for maturation and laying eggs.

The life span of a female summer time up to 3 months, and males up to 10-15 days. In autumn, gonotrophic harmony is disturbed, and two or three times blood feeding is required for the maturation of eggs. Blood is used not only for the development of eggs, but also for the formation of a fat body, thanks to which the fertilized females hibernate.

Each type of mosquito has certain morphophysiological and ecological features. Differences exist at all stages of development.

mosquito eggs Anofeles genera develop in reservoirs with stagnant and low-flowing water. They float alone on the surface of the water. Have air chambers. Culex mosquito eggs are elongated, laid in large groups (300-400 pieces each). Sticking together, they form a "boat" floating on the surface of the water. Mosquitoes of the genus Aedes lay their eggs one at a time at the bottom of drying up reservoirs.

mosquito larvae The genus Anopheles live in clear waters. They are worm-shaped. They are parallel to the surface of the water. They are held in this position with the help of palm-shaped bristles located on the segments. There are a pair of stigmas on the dorsal side of the penultimate abdominal segment. mosquito larvae genus Culex can live in polluted waters. On the penultimate segment of the abdomen, they have a respiratory siphon in the form of a narrow tube with a stigma at the free end. Therefore, the larvae of ordinary mosquitoes are located at an angle to the surface of the water. The last segment bears leaf-shaped anal gills and tufts of setae. Aedes mosquito larvae live in temporarily drying up reservoirs, puddles, tree hollows, water vessels, and can live in polluted reservoirs. The larvae feed intensively and grow, molt four times

and transform into the pupal stage.

Mosquito pupae. The body is shaped like a comma. Consists of a broad cephalothorax and a narrow segmented abdomen. The pupae do not feed. At the pupal stage, the internal organs are restructured, and organs characteristic of the imaginal stage appear. The main distinguishing feature of the pupa of the malarial mosquito is the shape of the respiratory siphon: the tube has a conical (funnel-shaped) shape. The pupae of mosquitoes of the genus Culex are characterized by the presence on the upper side of the anterior part of the body of two respiratory siphons in the form of cylindrical tubes.

Mature individuals (adults) are formed from pupae. Differences in winged forms are manifested in the landing, the structure of the appendages of the head and the color of the wings. When landing, the abdomen of the malarial mosquito is raised and is at an angle to the surface of the water, while that of the common mosquito is parallel to the surface. 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. Anopheles males have club-shaped thickenings at the ends of the mandibular palps, while Culex males have mandibular palps longer than the proboscis and do not have club-shaped thickenings.

The pubescence of the antennae is more pronounced in males and is a manifestation of sexual dimorphism.

Due to changes in environmental and socio-economic conditions in a number of southern CIS countries (Azerbaijan and Tajikistan), local outbreaks and epidemics of three-day malaria occur. Mass importation of malaria to Russia threatens the spread of malaria. Malariological situation on the territory Russian Federation has changed since 1996. The largest importation of malaria to large cities of Russia was noted in 2000.

Currently, the epidemiological surveillance of malaria in Russia is aimed at maintaining well-being in malariogenic territories, since there are many factors that increase the risk of malaria spread.

Factors in the spread of malaria:

a. Natural and climatic conditions: floods and floods; climate warming; the presence of numerous breeding sites for malarial mosquitoes;

b. Peculiarities certain types vectors and causative agents of malaria: susceptibility of mosquitoes to imported malaria pathogens; epidemiological effectiveness of local vectors; resistance of mosquitoes to certain insecticides;

c. Development economic activity population: rice cultivation; fish farming; cottage construction;

d. Migration of the population: flights of ships and aircraft to the tropics; tourism to endemic countries; the arrival of seasonal workers from endemic countries; nomadism of Tajik gypsies; business trips of businessmen to endemic countries;

e. Economic difficulties: reduced funding for antimalarial enterprises; deficit medicines for treatment and chemical prophylaxis; shortage of medical personnel exercising epidemiological surveillance;

f. Social and cultural level of the population: low level of knowledge of the population about malaria; lack of means of protection against mosquito bites among the population; non-compliance with the regimen of taking drugs; lack of insecticidal treatments of residential premises.

Mosquito control measures and malaria prevention. For personal protection, repellents and mechanical means are used: gauze curtains, nets, etc. The main measures of public prevention is the destruction of larval forms and breeding sites of mosquitoes. The fight against larvae consists of the following measures: 1) destruction of small abandoned water tanks; 2) spraying pesticides in reservoirs serving as breeding grounds; 3) oiling of reservoirs, preventing the supply 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, reclamation works; 6) biological control measures (breeding of mosquito fish); 7) the use of zooprophylaxis - the location of livestock farms between mosquito breeding sites and residential buildings. Insecticides are used to control winged forms.

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:

long-whiskered (mosquitoes and related groups)
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 closing 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 the salivary gland canal passes. All stabbing parts lie in a case formed by the lower and upper lip. The appendages of the lower jaws are the 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 oral 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 certain size whether they are edible 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 (gonotrophic cycle) occurs, 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 span of a female warm time year 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 genus Anopheles is raised and is at an angle to the surface, in the genus Culex, 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 in all stages of their life cycle. In the summer, winged mosquitoes are destroyed in the places of their daytime, and in the fall and early 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 for malaria 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. Rivers and streams are also not used with fast current. 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 by direct sunbeams. 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. Nice results gives biological method control: colonization of anophelogenous reservoirs by tropical fish Gambusia, 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:

destruction of any small abandoned water tanks;
spraying in reservoirs serving as breeding sites, pesticides;
oiling of reservoirs, preventing the flow of oxygen;
a change in the type of vegetation in a reservoir or a change in the degree of its overgrowth;
drainage of the area, land reclamation works;
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;
zooprophylaxis - when designing settlements, livestock farms are located between potential mosquito breeding sites and residential buildings, since mosquitoes readily feed on the blood of animals;
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 the wild and settlements. Habitats in settlements are burrows of house rodents, the space under the floors of residential buildings, at the base of adobe buildings, under heaps of construction debris, etc. In the wild, rodent burrows (gerbils, ground squirrels, etc.), nests birds, dens of jackals, foxes, caves, cracks, hollows of trees. 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 pricked by a mosquito P. pappatasii with the saliva of the latter, a pathogen can be introduced viral disease- Pappatachi fever. AT 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 is underway 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 settlements, insecticides are used to treat living quarters, and under natural conditions, rodents are destroyed in burrows.

The whole mass of flying blood-sucking dipteran insects is called midges. In the Siberian taiga, tundra and other places, dipterous bloodsuckers sometimes appear in myriad numbers, attack animals and humans in clouds, clog their 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. Distributed in various parts of the world, but carriers of diseases are only in Africa, South and Central America where pathogens of onchocerciasis are transferred. 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.

live in damp woodlands. 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. They cause itching, swelling, and in case of 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). Distributed throughout the 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 there is a mouth opening. The upper jaws and the first pair of lower jaws are atrophied. Upper lip and tongue are located on the front 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 matter. 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. They can breed all year round under favorable conditions. 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, garbage dumps, landfills, food industry waste. In rural areas, 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. The larvae go through 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 color(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 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 body surface with them, after which they transfer them to human food. 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 yellow color. 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) a fly sprays larvae on the fly, attaching them to the tissues of an animal or person, or, on occasion, to the eyes, nose, 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 eye socket, 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 sizes- 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. large insect, sizes more than 1 cm. Coloring 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 the introduction of medicinal preparations against sleeping sickness to healthy people. 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.