ANOFELES

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ANOFELES (Anopheles, from other - Greek ????????; Greek anuphelzs — harmful, dangerous) — a genus of blood-sicking mosquitoes of the Culicidae family (blood-sicking), a suborder of Nematocera (nematocera), Diptera group (flies); main carriers of causative agents of malaria. The sort combines more than 300 types and subspecies which are grouped in 6 subgenus.

Fig. 1. Eggs of subspecies Anopheles maculipennis: l — A. maculipennis melanon; 2 — A. maculipennis maculipennis; 3 — A. maculipennis atroparvus; 4 — A. maculipennis sachorovi; 5 — A. maculipennis subalbinus
Fig. 2. Larva of an anofeles: 1 — the head; 2 — a breast; I \VIII \VIII \— joints of an abdomen
Fig. 3. Doll of an anofeles: 1 — left: respiratory tube; 2 — - fins; 3 — the left eye

In the USSR 7 types of a subgenus of Anopheles — A. maculipennis meet (5 of its subspecies are registered: And. m. messeae, A. m. sacharovi, And. m. maculipennis, A. m. atroparvus, And. m. melanoon), A. hyrcanus, A. claviger, A. plumbeus, A. algeriensis, A. marteri, A. lindesayi and 2 types of a subgenus of Myzomyia — A. superpictus, A. pulcherrimus.

Anofeles are widespread in the countries with a tropical, subtropical and temperate climate. The northern border of their dwelling within the USSR passes apprx. 65 °C.

Tsikl razvitiya Highway And. there are of egg, larvae, the dolls (fig. 1 — 3) living in water and adult forms — the imagos populating the land. Female And. postpones for a surface of a reservoir of 200 — 260 eggs of a sigarovidny form supplied with special air chambers thanks to what they do not plunge into water. The upper surface of egg has hulls or strips or is painted monophonically. Larvae And. (the size 0,5 — 1,3 mm) the most part of life is carried out at a water surface and eat from its top skin. Larvae free air by means of the tracheas opening two stigmata on the back party of the VIII segment of an abdomen breathe. Larvae of different types Anofeles differ in a structure and an arrangement of klipealny, frontal and antennalny hairs on the head.

Larvae pass 4 stages in the development, turning after the 4th molt into a doll. The doll is slow-moving, does not eat and breathes by means of the respiratory tubules having conical shape. Places of breeding And. constants are and it is long the existing temporary natural and artificial reservoirs.

Fig. 4. Females of mosquitoes (view from a back): and — Anopheles maculipennis; — Anopheles superpictus

The long, slabovypukly breast with a tselnokrayny guard and long thin legs in small, skintight scales is characteristic of an imago Anofeles; mandibular palpus And. on length are equal to a proboscis (fig. 4).

Copulation And. occurs during the swarming. After fertilization females have a need for a krovososaniye since development of a portion of eggs is possible only in parallel with digestion of a portion of blood — gonotrofichesky harmony. An exception make A. claviger, A. hyrcanus and A. plumbeus at which the first yaytsekladka can occur without preliminary krovososaniye. During life the female does several yaytsekladok that causes a possibility of participation of mosquitoes in transmission of causative agents of diseases since each yaytsekladka is preceded by a krovososaniye, and each new krovososaniye is connected with a possibility of infection of a mosquito or the person from the infected mosquito. Females And. eat blood of mammals and the person. Males eat only juice of plants. Females of A. maculipennis, A. superpictus and And. pulcherrimus in search of production can make distant flights. Settlements of the person for them — the center of gravity. The area, about a cut mosquitoes are flown to the settlement, call a zone of inclination (its radius on the plain — up to 3 km). Settlements of a zone of inclination which partially match are called interfaced. Between them there is an active metabolism mosquitoes that should be considered in the analysis of an epidemiological situation. During the definition of extent of contact of mosquitoes with the person use an index of an antropofilnost (percent of the eating mosquitoes eating on the person from total number).

Digestion of blood at And. and development of eggs happens in shelters (halting day) of various type.

A. hyrcanus, A. claviger and other types choose shelters only in nature — ekzofila. Other types (endofil) are distributed between shelters in the nature and the settlement depending on degree of usefulness of their microclimate. The more mosquitoes there is for digestion of blood and development of eggs in constructions of the person, the endofilny population. After maturing of eggs of a female scatter in search of a reservoir for their otkladka. Within the next days the female sucks blood repeatedly. Thus, her life consists of a number of the following one after another gonotrofichesky cycles (see).

Fig. 5. Age changes of tubules of an ovary of an anofeles: and — a separate tubule from an ovary svezheokrylivsheysya females; — the same, from the female starting the first krovososaniye; in — after the first laying; — after three layings: 1 — region of growth; 2 — the second follicle developing in region of growth and the place which remained after its exit; 3 — the first developing follicle and the place which remained after its exit; 4 — a trailer leg of an egg tubule; 5 — the third developing follicle and the place which remained after its exit

On a leg of an egg tubule of a female determine number by number of expansions made it a yaytsekladok and her physiological age (fig. 5). The female, the more its epidemiological danger is more senior. Epidemiologically dangerous call females in whose body the cycle of a sporogony (came to the end see. Malaria ) and sporozoita appeared in sialadens. Practically define only the potentially dangerous females (PDF) in whose body the cycle of a sporogony could come to the end provided that infection occurred at the first krovososaniye. For calculation of age of POS it is necessary to know duration of a sporogony under existing conditions and physiological age, to-rogo the female will reach by this moment. With increase epidemiological value of population increases in population of number of POS.

Mosquitoes endure the autumn and winter period being able diapauses (see). For A. maculipennis, A. superpictus and A. hyrcanus is characteristic the imaginal diapause which is physiologically shown in braking of an ovogenesis. In the conditions of warm winter of a female of A. m. sacharovi, A. m. atroparvus, A. m. maculipennis and A. superpictus choose shelters in close proximity to an object of food and during the winter repeatedly suck blood that in the presence of parazitonositel can lead to emergence of the intra house centers of malaria. A. claviger, A. plumbeus, A. algeriensis, A. pulcherrimus, etc. have a larval diapause. In the spring at a favorable temperature of a larva finish the development and give rise to the first spring generation.

The number of generation in a year depends on weather conditions. Near northern border of an area of A. maculipennis gives to the 2nd generation in a year, in the Caucasus and in Central Asia — 6 — 8.

Medical Anopheles value

Part of types And. is specific carriers and final owners of causative agents of malaria (see) (Plasmodiuni vivax, P. falciparum, P. rnalariae, P. ovale). The plasmodium passes a certain development cycle in a body of mosquitoes — a sporogony owing to what infection with malaria, passing a carrier, is impossible. Infection of the person occurs at the time of a krovososaniye (specific inoculation), sporozoita get to a wound with saliva. It is proved that 65 types can be carriers of a plasmodium and subspecies the Anofeles which area defines nozoareat malaria. However the main carriers in world fauna consider 25 — 30 types living in various geographical zones. So, e.g., in the European part of the USSR and Siberia the main carrier is A. maculipennis, in Transcaucasia — A. maculipennis and And. superpictus, in Central Asia — And. maculipennis, A. superpictus and And. pulcherrimus; in Southeast Asia — A. minimus, A. culicifacies, A. sundaicus, etc.; in the Central Africa — A. gambiae, A. funestus; in South America — A. darlingi, A. albimanus, A. aquasalis; in Central America — A. albimanus, 4. pseudopunctipennis, A. aquasalis, etc. Minor carriers in fauna of the USSR: A.hyrcanus, A. claviger, in a number of areas — A. plumbeus.

Epidemiological value of separate types and populations Anofeles depends on specific conditions of this area and is defined by such factors as total number, extent of contact with the person, age composition and activity of population, a susceptibility to infection with plasmodiums. And. are also specific carriers of causative agents of malaria of animals (monkeys, rodents, birds, etc.) and specific carriers of the filarias including parasitizing at the person (Wuchereria bancrofti and Brugia malayi) and. at dogs (Dirofilaria immitis iiD. repens).

The role Anofeles in transfer of an arbovirus is small. So, in ChSSR from A. maculipennis Chalovo's virus is allocated. African types And. — carriers of causative agents of fever o'nyong-nyong.

Correctly to organize fight against a carrier, it is necessary to know their species composition, epidemiological value and biology of the main carriers.

Fight about Anofeles comes down to destruction of adult individuals and their larvae. For destruction of larvae use drugs from group of chlorinated hydrocarbons (DDT, GHTsG), organophosphorous connections (methyl nitrofos, a baytex, thiodiphenylamine), etc. DDT apply in the form of 10% of dust, consumption rate of 1 kg/hectare in a little overgrown reservoirs and 2 kg/hectare in strongly overgrown; GHTsG — in the form of 12% of dust, the same consumption rate. Technical powder of thiodiphenylamine is spent on 0,6 kg/hectare in poorly overgrown and on 1 kg/hectare in strongly overgrown reservoirs. It is possible to apply also Paris green (intestinal poison), spraying it on a top skin of water. Terms of processing establish according to data of phenological observations. Processing is begun at emergence in reservoirs of larvae of the II—III stage of development.

Biological methods of controlling are perspective: in the south — settling of reservoirs a viviparous small fish a gambusia, in northern areas — a whitebait of a grass carp.

Processing of settlements is carried out at detection in them of patients with malaria. In case of single diseases process the estate of the patient and the neighboring sites (microfocal processing). In the presence of several patients carry out continuous processing of the settlement.

Use of dust indoors is forbidden. DDT apply in the form of suspension or an emulsion (1 — 2 g of technical drug on 1 m 2 areas).

Residual effect of drug remains during the whole season.

During the planning of settlements it is necessary to be guided by the principle of zooprevention: to place the cattle on the edge of the settlement, distracting thus the most part of the flying mosquitoes. Apply the frightening-off substances (repellents) which apply on skin and clothes to individual protection: DETA, repellin-alpha, dimethyl phthalate, benzimine.

See also Mosquitoes blood-sicking , Carriers .



Bibliography: Beklemishev V. N. Ecology of a malarial mosquito (Anopheles maculipennis Mg.), M., 1944; Gutsevich A. V., Monchadsky A. S. and Shtakelberg of A. A. Komara, Gulicidae family, Fauna of the USSR, Insects dipterous, t. 3. century 4, L., 1970; Detinova T. S. Methods of establishment of age composition of the dipterous insects having medical value, the lane with English, M., 1962.


S. N. Zarechnaya.

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