Human flea medical significance. Synanthropic arthropods. Fleas, biology, epidemiological significance, methods of control and protection

Fleas. A-human; B-rat; IN- stomach of a gopher flea blocked by plague bacteria

Most famous human fleaPulex imtans And rat fleaXenopsylla cheopis. . Both species prefer to feed on the blood of humans and rats, respectively, but also easily switch to other types of animals. The rat flea lives in rat burrows, and the human flea lives in floor cracks, behind baseboards and wallpaper. Here, females lay eggs, from which worm-like larvae develop, feeding on decaying organic matter, including the feces of adult fleas. After 3-4 weeks they pupate and turn into mature insects.

Fleas visit humans at night. Their bites are painful and cause severe itching. But the main significance of fleas is that they are carriers of bacteria - pathogens plague Plague bacteria, once in the flea's stomach, multiply there so intensively that they completely close its lumen. This condition is called plague block. If a flea begins to feed on a healthy animal or person, after piercing the skin, it first burps a bacterial lump into the wound, due to which a huge number of pathogens immediately enter the bloodstream.

The natural reservoir of plague are rodents - rats, gophers, marmots, etc. These animals suffer from a number of other infectious diseases: tularemia, rat typhus etc. Therefore, fleas are known as carriers of pathogens and these natural focal diseases. It is interesting that in addition to the transmissible method of infection with these diseases, there are other ways: through contact with infected animals, by drinking water from open reservoirs, etc., but with a flea bite, infection is the most likely, and the clinical picture is the most severe.

Struggle with fleas - maintenance of residential premises and outbuildings clean, use of insecticides and various means of rodent control. Give effect and measures personal protection, such as repellents used on clothing and bedding.

Question 96. Order Diptera. Mosquitoes. Structure, development cycle, difference between the malaria mosquito and the ordinary one. Mosquitoes. Medical significance of mosquitoes and mosquitoes. Prevention measures.

Mosquitoes lay their eggs in water or on moist soil near water. Larvae and pupae lead an aquatic lifestyle and breathe atmospheric air using trachea. The larvae feed on tiny organic particles suspended in water. The most famous mosquitoes from the genera Culex And Aedes(non-malarial mosquitoes) - carriers of pathogens Japanese encephalitis, anthrax, yellow fever, and Anopheles(malaria mosquitoes) - specific vectors malarial plasmodium. It has been proven that the susceptibility of mosquitoes to infection with malaria pathogens is determined genotypically and is inherited monogenically. Malarial and non-malarial mosquitoes are easily distinguished from each other at all stages of their life cycle.

Eggs of malaria mosquitoes. Anopheles are located on the surface of the water singly, and each is equipped with two air floats. Their larvae swim in a horizontal position under the surface of the water, and on the penultimate segment they have a pair of breathing holes. The pupae are shaped like commas, are, like the larvae, under the water surface and breathe air oxygen through breathing horns shaped like wide funnels. Adult malaria mosquitoes, sitting on objects, are located at an angle to their surface with their heads downwards. The mandibular palpi, located on both sides of the proboscis, are equal in length or slightly shorter.

Mosquitoes on different stages life cycle.

A- Anopheles sp.;B- Culex sp.:

I - eggs, II - larvae. III - dolls, IV - imago; 1- air strikes, 2- egg raft, 3- breathing holes, 4- breathing siphon, 5-funnel breathing horns , 6- cylindrical respiratory horns, 7 - mandibular palps

Non-malarial mosquitoes pp.Culex and Aedes lay eggs that stick together in groups into small steel-gray rafts. The larvae are located under the surface of the water at an angle to it and have a long respiratory siphon on the penultimate segment. The respiratory horns of pupae have the shape of thin cylindrical tubes, and the mandibular palps of adult mosquitoes are short and reach no more than a third of the length of the proboscis. Non-malarial mosquitoes keep their bodies parallel to the surface on which they sit.

Fight with mosquitoes are most effective against the aquatic stages of the life cycle - larvae and pupae. Reclamation methods are used - filling ditches and quarries with standing water. It is possible to treat with pesticides individual reservoirs with a high concentration of larvae and pupae, as well as places of mass accumulation of mature stages of mosquitoes during the daytime (barns, barnyards). The most effective are biological control measures in combination with irrigation and drainage, carried out in accordance with state anti-malaria programs. Thus, in Western Transcaucasia, it was possible to quickly reduce the number of mosquitoes and the incidence of malaria in the population due to reclamation and breeding of fish - gambusia, which feed mainly on dipteran larvae. For personal protection repellents and mechanical means are used: gauze curtains, nets, etc.

Mosquitoes(family Phlebotomidae). Smaller insects 1.5-3.5 mm long, having a short proboscis, a strongly protruding thoracic region of the body in the form of a hump, and abundant drooping of the body and wings with small setae .

Mosquitoes lay their eggs in rodent burrows and other shaded areas with a lot of organic matter and high humidity. The larvae develop for about 2 months and then pupate. Sexually mature stages appear after 10-12 days.

Small blood-sucking dipterans.

A - mosquito; B - midge; IN - biting midge

Struggle with mosquitoes should be carried out comprehensively and aimed at the destruction of natural foci of leishmaniasis and other vector-borne diseases: this is the destruction of rodents and mosquito breeding sites, treatment of surfaces in outbuildings and dwellings with insecticides. Personal protection against bites is also effective.

Order Lice (Anopiura)

The head louse (Pediculus humanus capitis) lives on the scalp. The body length of the male is 2-3 mm, of the female - 3-4 mm. The rear end of the male's body is rounded, while that of the female is forked. The mouthparts are piercing-sucking type. It feeds only on human blood 2-3 times a day and can fast for several days. Eggs (nits) stick to the hair with a sticky secretion. A larva emerges from the egg and looks like an adult. After a few days, she turns into an adult. During her life (up to 38 days), the female lays about 300 eggs. The duration of the life cycle is 2-3 weeks.

The body louse (Pediculus humanus humanus) lives on underwear and bedding and feeds on humans. It is larger in size than the head one (up to 4.7 mm), has shallower notches along the edge of the abdomen and has weak pigmentation. Nits stick to the fibers of clothing. Life expectancy is up to 48 days, life cycle is at least 16 days.

Most Important epidemiological significance have lice as specific carriers of pathogens of relapsing and typhus. The causative agents of relapsing fever - Obermeyer's spirochetes - enter the louse's stomach with the patient's blood and from there into the body cavity (hemolymph). There is no exit gate from the carrier's body, so lice bites do not infect healthy person. The pathogen is transmitted only when the louse is crushed and its hemolymph is rubbed into the skin by scratching (specific contamination).

Order Fleas (Aphaniptera)

The flea's body has a dense chitinous cover, flattened on the sides. There are no wings. There are numerous hairs, bristles, and denticles on the surface of the body. The head bears short antennae and a pair of simple eyes. The last pair of legs is longer than the others and is used for jumping. The mouthparts are piercing-sucking type.

Fleas lay eggs in crevices and cracks in the floor, in dry garbage. Development comes with complete metamorphosis. The larvae are worm-shaped and have no limbs. After some time, the larva pupates. The minimum development period for a flea is 19 days.

Each type of flea has a specific host: rat fleas - rats, dog fleas - dogs, gopher fleas - gophers. But many types of fleas can feed on animals different types. Fleas feed only on warm blood. They leave the dead owner and look for a living provider. This feature has important in the rapid spread of the plague.

The secretion of the salivary glands of fleas when bitten causes itching and dermatitis in humans: when scratching the itchy areas, a secondary infection occurs. However, the main epidemiological significance of fleas is the transmission of pathogens of vector-borne diseases - plague and tularemia. Natural reservoir Plague is caused by various rodents - rats, gophers, tarbagans, marmots, etc. Plague pathogens actively multiply in the flea's stomach and close its lumen, forming a so-called "plague block". When sucking blood, the blood does not pass into the stomach and is regurgitated, carrying it into the wound a large number of plague bacteria. Infection of a person with plague is also possible through flea feces when they come into contact with the plague bacillus on skin damaged by scratching. A person can become infected with the plague through contact with sick animals (skinning) or with a sick person. Human susceptibility to plague is absolute.

Insecticides are used to control fleas. Preventive measures include: maintaining cleanliness in the premises, wet cleaning, elimination of cracks and crevices in the floor and walls, rodent control (deratization). In tropical countries it is not recommended to walk on the ground without shoes.

Class Insects. Order Diptera. Systematics, morphology, medical significance. Prevention of diseases they carry.

Order Diptera (Diptera)

The order includes a large number of species of medical importance. Representatives of the order have one (front) pair of membranous transparent wings. The posterior pair has turned into small haltere appendages that serve as an organ of balance. The large head is connected to the thoracic region by a thin soft stalk, which ensures its mobility. There are large compound eyes on the head. The mouthparts are licking, sucking or piercing-sucking.

Family Flies (Muscidae)

Of medical interest are flies - mechanical carriers of pathogens (house flies, meat flies, cheese flies, zhigalka, etc.) and specific carriers (tsetse fly). The larvae of some flies (Wohlfarth flies, gadflies) can be causative agents of diseases in humans and animals, which are called myiases.

The housefly (Musca domestical) is distributed throughout the globe. Females measure up to 7.5 mm. The body and legs are dark in color and covered with hairs. The legs have claws and sticky pads that allow flies to move on any plane.

The oral apparatus is licking and sucking. The lower lip is transformed into a proboscis; at its end there are two sucking lobules, between which the oral opening is located. The fly's saliva contains enzymes that liquefy solid organic matter, which it then licks off. Flies feed on human food and various decaying organic matter.

4-8 days after mating at a temperature environment At temperatures not lower than 17-18°C, the female fly lays up to 150 eggs at a time. Common places for egg laying are rotting organic matter, kitchen waste, manure, human excrement, etc. At optimal temperature(35-45°C) after a day, larvae emerge from the eggs, which pupate after 1-2 weeks. Pupation usually occurs in the soil at a lower temperature (not higher than 25°C). A new generation of flies appears in about a month. Their lifespan is about one month.

On the integument of the body, on the paws, on parts of the oral apparatus, flies mechanically transmit pathogens of intestinal infections (cholera, dysentery, typhoid fever), as well as tuberculosis, diphtheria, paratyphoid fever, anthrax, helminth eggs and protozoan cysts. There are up to 6 million bacteria on the body of a fly, and up to 28 million in the intestine.

Flies are controlled at different stages of their life cycle. To combat winged flies, insecticides, Velcro, baits with poisons are used, and they are destroyed mechanically. To combat preimaginal stages great importance has landscaping populated areas: availability of sewerage, closed garbage containers, manure storage facilities, toilets, timely disposal of waste, use of insecticides.

The autumn firefly (Stomoxys caicitrans) is ubiquitous. In morphology and biology, the firefly is similar to a housefly, but differs in its long, thin proboscis. It has a brown body color with dark stripes on the chest and spots on the abdomen. At the end of the proboscis there are plates with chitinous teeth. By rubbing the proboscis against the skin, the fly scrapes off the epidermis and feeds on blood; saliva contains it toxic substances, causing severe irritation. Its bites are painful. The population of flies reaches its greatest numbers in August-September.

The autumn fly is a mechanical carrier of anthrax and sepsis pathogens.

The tsetse fly (Gtossina palpalis) is distributed only in the western regions of the African continent. It lives near human habitation along the banks of rivers and lakes with high soil moisture, overgrown with shrubs and trees.

The fly is large in size (up to 13 mm), has a highly chitinized proboscis protruding forward and dark spots on the dorsal side of the abdomen. The body color is dark brown. Females are viviparous and lay only one larva on the soil surface. The larva penetrates the soil, pupates, and after 3-4 weeks the imaginal form emerges. Over the course of their entire life (3-6 months), females lay 6-12 larvae.

The tsetse fly feeds on the blood of animals and humans and is the main reservoir and specific carrier pathogens of African trypanosomiasis.

Measures to combat the fly consist of cutting down bushes and trees along the banks of rivers and lakes near settlements and along roads. Insecticides are used to control adult flies.

The Wohlfart fly (Wohlfahrtia magnifiea) is common in temperate and hot climates.

The body of the fly is light gray in color and has a length of 9-13 mm. There are dark longitudinal stripes on the chest.

The disease caused by the larvae of the Wohlfarth fly is called myiasis. Children are especially affected by myiasis. With intense infection, complete destruction of the soft tissues of the orbit and head is possible; sometimes the disease ends in death.

Occasional intestinal myiases can be caused by housefly and blowfly larvae.

1. Character traits organizations and medical significance of representatives of the class Insects.

Phylum Arthropods ( Arthropoda).

Subtype Tracheal-breathing ( Tracheata).

Class Insects ( Insecta).

Morphophysiological characteristics.

The body is clearly divided into three sections: head, chest, abdomen. Three pairs of legs are located in pairs on three segments of the chest, hence another name for the class - six-legged, or Hexapoda.

Digestive system represented by the foregut, starting from the oral cavity and dividing into the pharynx and esophagus, the posterior section of which expands, forming a goiter (not in everyone). Available salivary glands(up to three pairs), the secretion of which digests food. In blood-sucking insects, saliva contains a substance that prevents blood clotting. The midgut of insects is devoid of digestive glands, the hindgut ends with the anus.

The excretory organs are represented by Malpighian vessels (from 2 to 200) and the fat body, which performs the function of “storage kidneys”.

Respiratory organs - trachea. Stigmas are located segment by segment (up to 10 pairs). Large main trunks (tracheas) begin from the stigmas, which branch into smaller tubes. They even penetrate inside individual cells. Thus, the tracheal system replaces the functions of the circulatory system in supplying tissues with oxygen.

The circulatory system, in accordance with the characteristics of the respiratory organs, is relatively poorly developed. The heart is tube-shaped and consists of many chambers.

Nervous system reaches exclusively high level development. Consists of the brain and ventral nerve cord. The brain consists of three sections - anterior, middle, posterior and has a very complex structure. In the anterior part of the brain, mushroom bodies are highly developed, thanks to which insects are capable of forming complex conditioned reflexes. The behavior of insects, which is based on instincts, can be very complex (especially among social ones).

The sense organs (touch, smell, vision, taste, hearing) reach an exceptionally high level of development. The organs of vision play a leading role in orientation in external environment along with the olfactory organs. Insects have simple and complex ( faceted) eyes. Compound eyes consist of a huge number of individual prisms; this eye structure gives “mosaic” vision. Higher insects (bees, butterflies, ants) have color vision.

Insects are dioecious organisms; they have well-defined sexual dimorphism.

Life cycle.

In the Insect class there are Various types postembryonic development: direct and indirect (with complete metamorphosis). Complete metamorphosis includes the stages of egg, larva, pupa and adult. The larva differs sharply in structure and habitat from the adult forms. Thus, mosquito larvae live in water, and adults live in air environment. The pupae do not feed; at this stage, the larval organs are replaced by the organs of adult insects.

2. Lice (head, body, pubic)

Phylum Arthropods ( Arthropoda).

Subtype Tracheal-breathing ( Tracheata).

Class Insects ( Insecta).

Troop Lice ( Anoplura).

small sizes

limbs are equipped with a fixation device to the skin, hair and clothing

piercing-sucking type mouthparts

the development cycle is simplified (development with incomplete metamorphosis),

all stages of the life cycle live and feed on one host.

Head louse (Pediculus humanus capitis

Localized on the scalp. Dimensions 2-3 mm. The body is flattened, the head is small, well demarcated from the chest. On the head there is a pair of antennae, a pair of simple eyes (sometimes absent), and a piercing-sucking mouthparts. At rest, the oral apparatus is retracted inside the head and is not visible from the outside. The thoracic segments are fused, and the chest bears three pairs of legs. The last segment of the tarsus has a highly developed claw, which, together with the growth of the penultimate segment, forms a slamming device, like a claw. With this device, the louse is firmly held on the hair. There are no wings.

The abdomen is somewhat wider than the thoracic region and consists of 10 segments. In males, the copulatory apparatus is visible at the end of the abdomen. Stigmas are located on the lateral sides of the thoracic and abdominal segments.

Development with incomplete metamorphosis. The laid eggs (nits) are glued to the hair by the secretion of the adhesive glands. All development takes place on the human body. A larva emerges from the egg, similar in basic characteristics to the adult. After molting, she turns into an imago. They feed on blood. Maximum lifespan is 38 days.

Medical significance.

Prevention and control measures.

Cootie (Pediculus humanus humanus) causes the disease pediculosis.

Lives on underwear and clothing, and when sucking blood it spreads to the body. By appearance and development is very similar to a head louse.

Features:

has larger dimensions (up to 4.7mm),

less deep notches along the edge of the abdomen,

less pronounced pigmentation of the lateral parts of the abdominal segments.

Lays eggs on hairs of clothing.

The entire development cycle occurs in humans. Life expectancy is up to 48 days. Mobile, at a temperature of 27°C crawls 35 cm per minute.

Medical significance.

Only humans serve as the reservoir for both diseases. When sucking the blood of a sick person, pathogens enter the intestines of the louse, where they undergo a complex development cycle. Pathogens of typhus Rickettsia Provacek develop in the cells of the intestinal wall of lice, together with dead cells they enter the intestinal cavity and are carried out with feces. A lice bite is not dangerous, since there are no pathogens in the saliva. Infection occurs when insect feces are rubbed into a bite wound or into scratches and abrasions on the body.

Causative agents of relapsing fever Obermeyer's spirochetes From the intestine, lice pass into the hemolymph of the insect. Infection occurs when a louse is crushed and hemolymph enters the bite wound or scratches.

Prevention and control measures. Same as for head lice.

Pubic louse (Phthirus pubis). The disease is phthiriasis.

Dimensions 1–1.5 mm. The body is shortened, wide, narrowed posteriorly. The border between the chest and abdomen, as opposed to the head and body lice, not expressed. Life expectancy is up to 26 days.

Distributed everywhere. It lives on the pubis, armpits, and sometimes on the eyebrows and eyelashes. At the same time, it penetrates almost completely under the skin, exposing the tip of the abdomen, where the stigmas are located, to the surface. The female lays up to 50 eggs throughout her life.

Prevention and control measures.

First of all, it is necessary to maintain sexual hygiene. Otherwise, the same measures as for other lice.

3. Fleas.

Flea Squad ( Aphaniptera).

A typical representative is a human flea ( Pulex irritans). The flea's body is flattened laterally, there are no wings, the body length is from 1 to 5 mm. The head bears short antennae, a pair of simple eyes, and a piercing-sucking mouthparts. The limbs are highly developed, especially the last pair, which is much longer and is used for moving by jumping. The abdomen consists of ten segments; in males, the end of the abdomen is curved upward.

Development with complete transformation. Eggs are laid indoors in crevices, floor cracks, behind baseboards and wallpaper, and in dry garbage. IN natural conditions- in rodent burrows. A legless, worm-like larva emerges from the egg. white. It feeds on decaying organic matter, including the feces of adult fleas. After 3-4 weeks, the larva forms a cocoon and then turns into a pupa. Mature insects emerge from the pupa. Adult insects feed on blood.

Each type of flea lives on a host of a specific species: rat flea- on rats, dog - on dogs, gopher - on gophers. Some species can switch to animals of another species. This determines the importance of fleas as carriers of human diseases.

Medical significance.

Plague pathogens actively multiply in the flea's stomach, forming a plug that closes its lumen, or a “plague block.” When a flea tries to drink blood, the block interferes with the passage of blood, the flea regurgitates it into the wound and, thanks to this, introduces a huge amount of bacteria into the host’s body. Currently, it is believed that infection through a bite is possible only when a block is formed. Infection is also possible through flea feces, which contain plague pathogens when they get into wounds when scratched.

The most dangerous carriers of plague are the rat flea and the marmot flea. Human flea can also be a carrier of plague.

A person can become infected with plague not only through carriers, but also through contact with animals (for example, when skinning) or with a sick person. The pneumonic form of plague is especially easily transmitted. In addition to plague, fleas can transmit tularemia.

Prevention and control measures.

Prevention measures include ordinary sanitary and hygienic measures: maintaining cleanliness in the premises, wet cleaning, eliminating flea breeding sites such as crevices, cracks in the floor, etc. Insecticides are used to kill fleas indoors or on clothing.

IN field conditions destroy rodents in burrows using appropriate pesticides and thereby eliminate fleas.

Personal protective measures, such as repellents that are applied to clothing and bedding, also have an effect.

4. House fly, house fly, Wohlfarth fly.

Order Diptera ( Diptera).

The order includes the largest number of species of medical importance. Representatives of the order have one (front) pair of transparent membranous or colored wings. The posterior pair has turned into small appendages (haleteres) that perform the function of balance organs. The head is connected to the chest by a thin soft stalk, which provides greater mobility.

Housefly (Musca domestica).

Distributed throughout To the globe. Quite a large insect of a dark color. Body dimensions 6-8 mm, color gray-brown. On the sides of the head there are large compound eyes. Four dark longitudinal stripes stand out on the chest. The legs have claws and adhesive blades that allow the fly to move along any plane.

Oral apparatus – licking-sucking. The saliva of flies contains enzymes that dissolve solids. After the food is liquefied, the fly licks it off. The fly feeds on human food and various organic substances.

Flies lay eggs (100-150 pieces) in rotting substances of plant or animal origin. In urban settlements, these are accumulations of food waste in garbage dumps, garbage receptacles, landfills, waste Food Industry. IN rural areas breeding sites include accumulations of domestic animal manure, human feces, and human feces on the soil. After 5-10 days, a segmented white worm-like larva emerges from the egg. It feeds on liquid food, mainly decaying organic matter. Optimal conditions For development, larvae (temperature – 35-45°C, humidity – 46-84%) are created in manure heaps. After 4-7 days the larva will pupate.

The pupa is motionless, covered on the outside with a thick cuticle Brown. The fly coming out of it passes through quite thick layer soil. Flies become sexually mature on days 5-6. Life expectancy is about 1 month. During this time, the female lays eggs 5-6 times (about 600).

Medical significance.

The housefly is a mechanical carrier of pathogens 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 contaminated feces and ingest pathogens of intestinal infections or contaminate the surface of the body with them, after which they transfer them to human food . Pathogens enter the human intestine with food, where they are found favorable conditions. In fly excrement, bacteria remain alive for a day or more. In addition to intestinal diseases, houseflies can carry pathogens and other diseases, for example, diphtheria, tuberculosis, etc., as well as helminth eggs and protozoan cysts.

House fly (Muscina stabulans).

Distributed everywhere. Body colored brown, legs and palps yellow color. It feeds on feces as well as human food. The main breeding sites are human feces in unsewered latrines and on the soil. In addition, it can develop in the feces of domestic animals and food waste. Adult flies live in yard latrines.

Medical value: mechanical carrier of pathogens of intestinal diseases.

Fighting flies.

timely collection and disposal of waste, at least once every three days,

garbage dumps and latrines must be hermetically sealed and easy to clean,

prevent soil contamination with human feces,

Insecticides and larvocides are used in fly breeding areas.

Distributed in the Caucasus and Central Asia, but can also be found in more northern regions.

A large fly, light gray in color, with black round spots on its abdomen. Viviparous. Attracted by the smell of decomposing tissues (wounds, purulent discharge), the fly incurs larvae into the tissues of an animal or a person, which immediately penetrate into soft fabrics and feed on them there. Before pupation, the larvae leave the host and go into the soil. During one clutch, the fly hatches up to 120 larvae. Adult forms feed on flower nectar.

Medical significance. Children are especially affected by myiasis. 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.

Mosquitoes.

Order Diptera ( Diptera). Family Mosquitoes ( Culicidae).

Blood-sucking insects. Distributed from the tundra zone to desert oases. On the territory of Russia, three genera are most often found: Anopheles, Culex, Aedes.

Small insects with a narrow and elongated body. The head bears large compound eyes. The mouthparts are piercing-sucking, but only females are bloodsuckers, and males feed on nectar and have sucking mouthparts.

Development with complete transformation. Eggs are laid in water or wet soil. The larva that emerges actively feeds and molts several times. The body of the larva is clearly divided into head, thorax and abdomen. The head is round in shape, bears antennae, eyes and fan-shaped fans. As they move, the fans force water and the particles it contains into the larvae’s mouth. 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 into water bodies.

The respiratory organs are the trachea.

The pupa has a comma shape due to its massive cephalothorax and narrow abdomen; it does not feed and moves with the help of rapid movements of the abdomen.

Hatched females and males live near bodies of water, feeding on nectar. After fertilization, females need to drink blood to develop eggs, so they actively search for a host and are able to detect it at a distance of up to 3 km using smell and then vision. Females suck the blood of animals or humans. During the digestion of blood, the eggs mature (gonotrophic cycle), which lasts 2-3 days. Some mosquito species have only one gonotrophic cycle per summer, while others may have several cycles.

Mosquitoes are most active in the evening and early morning hours. During the daytime hours high temperature and low air humidity, mosquitoes are in shelters and do not feed.

Life expectancy of a female warm time years up to 3 months, and males - 10-15 days. In the fall, the males die, and the females go into suspended animation and overwinter.

Each type of mosquito has its own ecological characteristics, so organizing control measures requires precise definition genus present in a given 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, as reflected in the table:

Prevention and control measures.

Personal: protection against mosquito bites.

Public prevention: destruction of mosquito larvae and breeding sites. The pupae cannot be destroyed because they do not feed and are protected by thick chitin.

The fight against larvae consists of a number of measures:

destruction of all small abandoned water tanks;

spraying pesticides into reservoirs serving as breeding sites;

oil production small bodies of water, preventing the flow of oxygen;

drainage of the area, reclamation work;

biological control measures: breeding mosquito fish that feed on mosquito larvae;

Fighting imago:

zooprophylaxis – between mosquito breeding sites and residential buildings livestock farms are located, since mosquitoes readily feed on the blood of animals;

spraying insecticides in areas where mosquitoes hibernate: basements, attics, barnyards.

6. Mosquitoes

Order Diptera ( Diptera).

Family Mosquitoes ( Phlebotomidae).

Only mosquitoes of the genus are of medical importance Phlebotomus.

Small insects - body length 1.5-3.5 mm. The color is brown-gray or light yellow. The head is small, bears 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 external parts of the genital apparatus. The legs are long and thin. The body and wings are heavily covered with hairs.

Mosquitoes are found in tropical and subtropical zones on all continents.

Development with complete metamorphosis. The eggs are brown, elongated oval in shape. The larva is legless with a head covered with hairs and lives in the soil. Feeds on organic matter. The pupa is club-shaped and does not feed.

Males feed on plant sap; Only females drink blood. Just like female mosquitoes, female mosquitoes have a gonotrophic cycle. However, many species of mosquitoes suck blood repeatedly during egg maturation. Capable of transovarial transmission of pathogens.

Mosquitoes are crepuscular and nocturnal insects. They attack prey before sunset and in the first hours after sunset. outdoors and indoors. Can live in the wild and populated areas. Habitats in populated areas include burrows of house rodents, the space under the floors of residential buildings, at the base of adobe buildings, under heaps construction waste etc.

In the wild, breeding sites include rodent burrows (gerbils, gophers, etc.), bird nests, jackal and fox dens, caves, cracks, and tree hollows. From their holes, mosquitoes fly to villages, covering a distance of up to 1.5 km.

Medical significance.

Prevention and control measures.

In villages, residential premises are treated with insecticides; in natural conditions, rodents in burrows and mosquito breeding sites are destroyed. Also effective individual means protection from bites.

Prevention and control measures. To combat cockroaches, insecticides are used, various

decoys and other means. Must be made inaccessible to them food products and water, then they themselves will look for another habitat.

Family Cimicidae (bed bugs). Morphology and developmental biology. People are being attacked Cimex lectularius And C. hemipterus.Bed bugs(Fig. 4.25) have a flattened body with lost wings. Oral apparatus piercing-sucking type. The eyes are bulging, but they see bugs

Badly. They have the most developed sense of smell. Bug on the big one

Distinguishes the smell of prey from a distance (up to several meters) and crawls towards it. The legs are running, with three-jointed tarsi.

The size and color of the bug depend on the degree of its saturation: a bug that has sucked blood swells to 0.5-0.8 cm, its color becomes redder. The saliva contains poisonous secretions, so the bites are painful. Representatives of this family are characterized by odorous glands. The eggs have a cap at the upper end.

Female bed bugs lay 1 to 12 eggs daily,

Rice. 4.25. Bed bug Cimex lectu-

laris.

which are glued with a gelatinous secretion to walls, furniture and other places. At room temperature The development of the egg until one larva emerges lasts 6-8 weeks. To transition to subsequent stages of development, the larva must be pumped with blood each time, and the volume of blood consumed increases from 1-3 to 7 mg. Older larvae and mature bedbugs can fast for 18 months. A hungry bug becomes almost transparent, flat and colorless. A bed bug is nocturnal, but a hungry bug’s behavior changes: it crawls out “to hunt” even in bright light. An adult bedbug covers a distance of over 1 m in 1 minute. Other types of bedbugs can also attack humans, the natural hosts of which are pigeons, barn swallows or the bats. In the absence of people, they bite mice, rats, chickens and other animals. Blood sucking lasts about 10-15 minutes in adults and less in nymphs and is repeated every 3 days. During the day, insects hide in dark, dry places in beds, mattresses, wall cracks, floor crevices and furniture. They can also be found behind paintings and wallpaper. They breed in places of shelter. In countries with warm climates, bedbugs are present in abundance in bedrooms. In colder climates, they live in heated bedrooms because they can only thrive at temperatures of at least 13°C. Adults can survive without food for several years. Bed bugs are ubiquitous.