Why do we need ticks in nature? Parasitiform mites Who eats mites in the food chain

Every year the area of ​​distribution of ticks increases, there are more and more of them. Together with them, the number of deadly diseases transmitted to animals and humans by these dangerous predators is growing.

Today it is easy to pick up a tick in a city square or in a park, in a personal plot and in a garden. Creatures in chitinous shells are increasingly squeezing the ring around a person.

You can learn about what the tick eats and its habits by reading this article.

About the types of ticks

All mites belong to the order of small arachnids, uniting about 20 thousand species. What does a tick eat besides blood? Some of the ticks below also feed on other types of food.

The largest group of soil mites are shell mites. They live in forest soils and litter. They chew on rotting plant remains with abundant microflora with their gnawing chelicerae. They carry tapeworms that infect livestock.

Small insects that gnaw with their chelicerae are barn mites (or bread and flour mites). They live in decaying plant debris and in the soil. In storage of agricultural products, they cause spoilage of flour, grain and cereals. In people working in such premises, they can cause severe skin irritation in the form of an allergic reaction. The tick feeds on insect tissue.

The best studied is a serious pest of poultry farms. What does chicken mite eat? They are active at night, when they come out of the crevices of the chicken coop and, attacking chickens, suck their blood. It also happens that with a massive defeat, birds die from anemia.

To learn more about what ticks eat in nature, let's get acquainted with the most dangerous ticks for humans.

Encephalitic mites

Below are the ticks that are the most aggressive.

Tick-borne Encephalitis- one of the most common and famous. It is important to note that the encephalitic tick is not a separate breed (species) of arthropod insects. Encephalitis can infect any variety of ticks, so it is impossible to identify the signs that determine the degree of danger. But it should be remembered that such an infection can lead to death of a person.

By the appearance of an insect, it is impossible to determine whether it is encephalitic or not, therefore, when going into the forest, the necessary measures should be taken to protect yourself from contact with predators.

It is the ixodid ticks that most often act as carriers of dangerous encephalitis. They also have a second name - hard mites. They owe this name to a hard chitinous coating, which is a kind of protective shell. Ixodes include both dog and taiga ticks.

The habits of forest ticks

What do ticks eat in the forest? The blood of various animals and humans.

As a rule, ticks rarely rise above a meter from the ground, and when attacking a victim, they try to move higher to the softest areas of the skin. Female ticks are more voracious, they can suck blood for 6 days without stopping, while males need 3 days to saturate.

Relatively small, their size in a state of hunger in length does not exceed 4 mm. When sucking blood into large volumes sizes can increase up to 120 times.

The bite of the tick is not felt, because the insect injects a special saliva that blocks pain in a person. In this regard, the tick can long time unknowingly feed on blood.

An excellent sense of smell helps the tick to detect the victim. In order for a predator to climb onto a person, it is enough for the latter to stop in the forest even for a couple of minutes.

About diseases carried by ticks

Knowing what the tick eats, it should be remembered that it is a carrier of various diseases.

In fact, there are many, but 2 species mainly have a real dangerous epidemiological significance: Persulcatus (or taiga tick), which lives in the European and Asian parts of Russia; Ixodes Ricinus (or European forest tick) - in the European part.

Ticks can be carriers of the following diseases:

• encephalitis;
• tick-borne typhus;
• Lyme disease (or borreliosis);
• hemorrhagic fever;
• spotted fever;
• fever Marseilles;
• babesiosis;
• tularemia;
• erlichiosis.

Many of these diseases are dangerous and not very treatable, and some show signs only 10-20 days after the bite.

Important information

After it became known what the forest tick eats and what it can lead to, you should know how to protect yourself from predatory insects, and what to do if the tick nevertheless sticks. Be sure to remember that the part that sticks into the skin (proboscis) is equipped with small "thorns". They are directed towards the back of the tick.

Therefore, if it is pulled along the axis, the "thorns" bristle and dig even harder into the skin, which can lead to the separation of its proboscis from the body of the tick, which can forever remain in the dermis.

To avoid this, the insect should be removed in a circular motion (unscrewed), and not just pulled out. In this case, the spikes on the proboscis will curl up to the axis of rotation, while the head will not come off.

If this could not be done correctly, the suction site (where the head remained) should be wiped with cotton wool moistened with alcohol, after which the head should be removed with a sterile needle as an ordinary splinter.

Conclusion

Ticks are creatures that, if necessary, can in nature for a long time (even months), and in laboratories and for years, do without food.

This is due to their inactivity and, in connection with this, a rather economical expenditure of the body's energy reserves.

connected by one chain. N.M. Zhirmunskaya

In this case, we mean not a real iron chain, but the so-called food chain. Although this chain is invisible, its iron grip inexorably guides many biological processes and allows you to maintain the balance in nature.

Equilibrium is the main law of nature. But we just violate it when we plant gardens and vegetable gardens and forget that with all our technical and chemical achievements, we cannot escape from nature, which means that, whether you like it or not, you must comply with its laws.

Consider one of the food chains that exists in our garden. It consists of the following links:

The first is plants that serve as food for herbivorous insects (phytophages);

The third is entomophages, which feed on phytophages and themselves serve as food for birds, amphibians, etc.

In this chain, phytophages are in the most advantageous position, the very ones that, in our view, are united by one name - pests.

Their food is always available in abundance. Since the amount of food is unlimited, they could also reproduce indefinitely, but this does not always happen, since, in addition to food, the ability to reproduce depends on many other conditions, including climatic, space, and also on the presence of natural enemies. But since these conditions are constantly changing, the number of phytophagous pests varies from season to season. We see this in our garden. One year we breathe a sigh of relief: no aphids, no weevils. Another year, if in autumn and winter favorable conditions develop for laying eggs and overwintering of these and other small creatures like them, then in spring we see with horror our fruit trees and berry bushes, covered with hordes of pests.

Entomophages are not in the best position either. True, our joys turn into grief for them, and vice versa. When there are few pests, they have nothing to feed their young, and then their numbers are greatly reduced. When there are a lot of pests, they are created for them excellent conditions for breeding and their population is increasing.

At first glance, everything looks quite safe: the mass reproduction of pests is accompanied by the mass reproduction of entomophages. The second eat the first and bring their number to an acceptable level.

Everything would be so if it were not for a certain delay in the reproduction of entomophages in comparison with the reproduction of pests. It is late / exactly at the time it takes for the larvae and adult insects to develop from the laid eggs, and this is usually 2-3 weeks.

In early spring, in April, we can observe the first stage of confrontation between predators and their prey. As soon as the sun begins to warm, the first predators wake up - spiders and bedbugs.

Spider and prey

Spiders and Spiderlings different sizes live both in the ground and on the branches of shrubs. They prey mainly on adult insects that have not yet left the stage of winter dormancy.

In April, predatory anthocoris bugs awaken, which move to apple trees and begin to suck out the contents of wintering eggs of red and brown fruit mites, aphids, suckers and leafworms.

Both adult bugs and their larvae are equally voracious. In the spring, they eat the eggs of the pests mentioned above.

An adult bug can destroy a thousand individuals of a red apple mite in one day. At the same time, without harming either plants, or humans, or the same predators as himself.

During the day, the larvae of the predatory bug anthocoris destroy up to 300 eggs or up to 250 larvae of the currant gall midge, and in an hour - 50 - 60 spider mites.

When adults emerge from eggs in summer, they also eat adults. Bed bugs do not miss aphids, or suckers, or leafworms, but fruit mites and especially their eggs remain their favorite food.

At first, there is not much of it and it does not have a strong damaging effect on the shoots, but aphids have an unlimited ability to reproduce. Over the summer, they give 11-13 generations and, if nothing interferes, their number grows like an avalanche. Aphids breed especially intensively in the second half of summer after June 24, when the composition of plant sap changes (the content of carbohydrates increases in it, and this stimulates the feeding and reproduction of aphids). And they would multiply indefinitely if not for their many natural enemies.

Several species of predatory spiders and 21 species of predatory insects feed on aphids, including ladybugs, lacewings, predatory bugs, syrphid flies, predatory gall midges. The faster the aphids reproduce, the more active the predators that feed on them.

Syrphid flies lay their eggs directly in the colony of aphids, and the larvae of flies that degenerate from eggs eat aphids from late May to August.

In June-August, aphids are eaten by the larvae of the silver fly. By the joint efforts of predators of different species, the number of aphids in the second half of summer, as a rule, decreases to an acceptable level.

As a result, a trichogram comes out of the egg instead of the codling moth. They learned how to breed Trichogramma artificially, and if it is released in the garden early in spring, then damage to apples by codling moths can be significantly reduced.

Others lay their eggs in the body of caterpillars or larvae. So do most ichneumonid riders, tahini flies.

Then she lays an egg on the caterpillar, closes up the entrance to the mink with a pebble and flies away with a calm soul. After hatching from the egg, the larva will find a sufficient supply of food.

Ground beetles are active predators, everything that lives on the surface and shallow under the soil surface becomes their prey. AT middle lane Several hundred species of ground beetles have been discovered in Russia, but only five species are the most common and numerous.

Ground beetles are rather large beetles with rigid elytra, which, depending on the species, have a color from blue-black to copper-red. Ground beetles have such properties that make them very effective entomophages - gluttony, aggressiveness, high fertility, abundance and long life expectancy.

Their victims are eggs, larvae and adults of the most various kinds insects, but it is very important for us that the ground beetle eats the larvae of the Colorado potato beetle, which even birds refuse because of their disgusting taste.

The Colorado potato beetle produces two generations during the summer. Larvae of the most harmful first generation at the beginning of summer are not very accessible to ground beetles, as they sit high on potato bushes, and ground beetles run mainly on the ground. But after heavy rain, wind or hilling, many larvae fall to the ground and become victims of a predator. Ground beetles destroy from 30 to 70% of the larvae of the first generation.

The second generation of Colorado potato beetle larvae develops in the second half of summer, when potato tops grow and fall to the ground. At the same time, the period of the greatest activity of ground beetles begins. One ground beetle can eat an average of 26 Colorado beetle larvae per day.

In total, ground beetles eat from 60 to 100% of the eggs and larvae of the second generation of the Colorado potato beetle.

Accordingly, the number of the beetle that leaves for the winter and attacks the potato fields in the spring of the next year decreases.

In the fight against Colorado potato beetle ground beetles are helped by ladybugs, lacewings and predatory bugs.

In addition, it turned out that this bug can be bred in artificial conditions and at the right time to release to the potato fields. But best of all, he proved himself on eggplant.

Slugs and flies are the favorite food of lizards.

It is not so difficult to choose a place on the garden plot, the lizards will be comfortable eating. It should not be sunny, but not without sunlight, the site is wet. A few stones, an old stump will help the lizard brought from the forest to take root with you.

The toad has neither sharp teeth nor wings to chase insects like a bat.

And yet, she is one of the gardener's best friends. The toad hunts only at night. And this is the favorite time of slugs.

Over the summer, 100 worms on one square meter soils lay kilometers of passages, making it loose, water and breathable.

On land where there are a lot of worms, and this is determined by holes in the soil surface, you can grow everything without fertilizing.

Predatory entomophagous insects make a great contribution to curbing the reproduction of harmful insects. The value of this contribution varies greatly depending on certain conditions. Among these conditions, not the last place is occupied by the availability of food, just something that the gardener has the opportunity to influence in a certain way and thereby contribute to an increase in the number of entomophages. Here we again for the umpteenth time mention hedges.

In hedges there is always a large number of various insects: both harmful and beneficial. There they are in balance. The latter eat the former and thus do not allow them to multiply uncontrollably, but at the same time they never completely destroy them, thus maintaining their food and, accordingly, their numbers at a sufficiently high level.

If mass reproduction of pests suddenly begins in the garden, the entomophages will be ready to move to cultivated plants and help the gardener cope with this disaster. In this case, the sequence of events that is typical for a garden without hedges is violated:

Without top dressing, they live 2-3 days, and with top dressing, 9-15. This significantly increases the time during which the riders infect the pest caterpillars.

It is known that beneficial insects prefer small flowers of plants from the umbrella family, complex and cruciferous. In the best case, by successive sowings, a permanent conveyor of nectar-bearing plants should be organized, supplying entomophages with food from spring to autumn.

anise flowers

Predatory wasps and flies are attracted by flat open flowers of daisies, chamomile, as well as mint, savory.

daisies

Savory garden Argonaut

It is important to provide predatory hoverflies with early flowering plants.

Hoverflies, or Flower Flies (Syrphids)

When in the spring they wake up from hibernation, they need food at the same time. If they do not find the necessary food at this time, their larvae, active aphid eaters, will appear too late, only in August.

In addition to feeding, beneficial insects require sun-protected, shady, moist habitats and plants suitable for oviposition.

Spiders and ground beetles prefer to live and lay their eggs in tall grass under hedge bushes, from where they make hunting raids on garden beds at night.

Ground beetles overwinter in the soil. Scientists have found that their number can be increased by 1.5 times if they create favorable conditions for overwintering, loosening and preparing the ridges for planting potatoes in the fall.

For oviposition, lacewings choose thickets of ferns and evergreen shrubs. In the garden, it is desirable to keep a certain amount of wild flowering plants, for example, tansy, chamomile, yarrow, on which the ladybug likes to lay eggs.

Tansy

Daisies

yarrow

Another technique is hanging bundles of straw or reeds in places sheltered from the rain. This is convenient places for
oviposition of many beneficial insects.

For catchers of aphids and codling moths - earwigs on apple trees are hung upside down small flower pots stuffed with dry grass and all sorts of rubbish.

Earwig

There the earwig hides during the day. because it leads a nocturnal lifestyle. She also lays her eggs there.

Consider another type of beneficial insects - pollinators. Hedgerows with flowering bushes are one way to attract them.

Another way is to create living quarters for wild bees. For this purpose, an old log with a large number of holes drilled in it serves. It is reinforced in vertical position and covered with a rain cap.

After all of the above, it is hardly worth convincing gardeners to abandon the use of pesticides. Pesticides destroy the living chain and create all the conditions for the uncontrolled reproduction of pests.

First of all, beneficial insects die - predators that live openly and do not hide, like pests in various secluded places: under bark or lumps of soil. By using pesticides, you are captured by them, as you destroy your allies and are left with the problem of protecting your garden one on one.

Each of us, of course, heard about very "bloodthirsty" animals called ticks, and many of us met them personally in natural (and not only) conditions. In fact, ticks, like any other animals, cannot be classified only as extremely harmful or deadly creatures.

Any species or taxonomic group of species should be considered only in conjunction with the characteristics of their phylogeny (origin), habitat, and relationships with other animal and plant species. The complex of these factors determines its place in nature, while the consideration of any species from the point of view of usefulness or harmfulness seems to be an outdated and primitive approach that does not correspond to modern scientific ideas.

Who are ticks

The branch of zoology that studies ticks is called acarology. According to one of the accepted modern classifications of invertebrates, mites belong to the phylum Arthropoda, the subphylum Cheliceraceae, the class Arachnida, the subclass of mites, which currently has a little over forty-eight thousand species.

Unfortunately, recently the negative impact of ticks on human health has become more and more pronounced, which will be discussed in detail below.
A detailed analysis of the role of ticks in nature would take too much time, so we confine ourselves to a brief excursion into the main points of their participation in processes in the environment, as well as in the human economy.

Blood-sucking mites

The greatest danger to humans and animals is posed by blood-sucking mites, primarily because they are able to retain and transmit pathogens of a number of serious infections from animals to humans for a long time. It is they who, as a rule, are given the most close interest in various kinds publications intended for a wide range of readers, which is not surprising, since almost everyone has heard about dangerous diseases, often fatal, spread by blood-sucking ticks.

How to remove a tick yourself

You can try to remove the tick yourself at home, although some sources do not recommend doing this, and this seems to be correct. If you already do it yourself, then it is most convenient to do this with small curved tweezers.

The tick is captured as close as possible to the proboscis, and by sipping and rotating the tick around its own axis, they are removed along with the proboscis. You can use a loop of thread, grabbing the tick as close to the head as possible. Do not crush the tick with your fingers, and also lubricate it with various fats, such as oil.

If the proboscis still remains in the wound, then this is not fatal. With a proboscis sticking out above the surface of the skin, you can unscrew it with tweezers, or contact a surgeon at a clinic. You can’t cut or pick at the bite yourself. Also, you should not try to burn the tick with a cigarette.

Diseases caused by ticks

Diseases of humans and animals caused by ticks are called acariases. Diseases that have developed as a result of the transmission of the pathogen by blood-sucking arthropods (in particular ticks) are called transmissible. There are specific carriers, that is, those in which the pathogen goes through any stage of its development (or multiplies), and mechanical, in which the infectious agent does not develop and does not multiply, but once on the mouth apparatus or in the intestine is transmitted directly through a bite or contamination (infection) of wounds and mucous membranes of the host.

The causative agent of any infection can be transmitted only through a vector (obligate-transmissible diseases, such as leishmaniasis), or in other ways (through animal products, through the respiratory system). Not all ticks acquire pathogens through direct contact with them.

In 1940, Academician E.N. Pavlovsky put forward the doctrine of the natural focality of diseases. According to him, these diseases are closely related to a complex of natural conditions and exist in natural environment regardless of the person. A natural focus is a certain geographical landscape in which the pathogen circulates from the donor to the recipient through the carrier. Donors of the pathogen are animals that have become ill with any transmissible infection, or are a natural reservoir of the pathogen, without infection of the carriers themselves. Recipients of the pathogen are sick animals (or humans) that become donors after infection.

Thus, we see that the following components are included in the natural one:

1. the causative agent of the disease;
2. carrier of the pathogen;
3. pathogen donor;
4. pathogen recipient;
5. certain natural biotope.

The frequency of infection of the recipient in the focus, as well as the pathogenesis of the disease, will depend on the degree of pathogenicity of the pathogen, its dose, the frequency of the vector attack on the recipient, and the presence or absence of prior vaccination.

Now let's move on to a more detailed consideration of various infectious diseases, pathogens that cause them, and an assessment of the role of species and groups of ticks involved in the transfer process.

People and animals are attacked by ticks that belong to the following families: Gamasoidea (gamasid mites), Argasidae (argas), Trombidiidae (red ticks), Ixodidae (ixodidae). The argasids and ixodids are combined into the superfamily Ixodoidea. Interestingly, some types of ticks never attack a person, others only in cases where there is no main host (so to speak, from starvation), and for others, a person serves as a common victim.

Russia, due to the vastness and heterogeneity of its territories, is one of the largest global areas for infectious diseases carried by ticks. In general, they spread more than 20 infectious diseases in the CIS.

One of the most dangerous infections transmitted to humans through ixodid ticks are various encephalitis.
In a broader sense, encephalitis is a neuroinfection, most often of a viral nature, it can also sometimes occur as a complication of certain infectious diseases. As a rule, they proceed severely, with lesions of the nervous system in the form of paralysis, deafness, respiratory failure, convulsions may develop, and deaths are not uncommon, especially in late diagnosed cases.

Tick-borne encephalitis(CE), also spring-summer or taiga - primary viral encephalitis caused by arboviruses, occupies a leading position in Russia and in many European countries. You can also become infected with it by eating raw cow or goat milk(alimentary path). The incubation period is 5-25 days, with alimentary penetration 2-3 days. It has three main genotypes of the virus - Far Eastern, Western, and Ural-Siberian.
The disease begins acutely, there is chills, fever to pyretic and hyperpyretic levels, severe headache(cephalgia), myalgia, lethargy, drowsiness, less often agitation. The skin of the face, neck, upper part of the body is hyperemic.

It usually proceeds as three forms: febrile, meningeal (with the addition of meningeal signs) and focal (convulsions, impaired consciousness are characteristic), the latter being highly lethal. This disease has several characteristic features that are specific to it. One of them is severe lesions of the nervous system, manifested by paralysis and paresis of the neck and upper limbs, muscle atrophy, and in some cases the Kozhevnikov epilepsy syndrome. Also characteristic feature CE is the possibility of developing a chronic progressive process, almost invariably leading to death. Currently, there is no radical treatment for the consequences of CE. But against this formidable disease, nevertheless, you can protect yourself by carrying out prevention - the introduction of a vaccine against tick-borne encephalitis.

As for the dynamics of the spread of this infection, according to Rospotrenadzor data over the past fifteen years, the territory where tick-borne encephalitis is endemic is steadily expanding, and there has also been an increase in the number of individuals in whose bodies the causative agent of this infection has been directly isolated.

Among the leading regions in terms of the incidence of this disease are the Perm and Krasnoyarsk Territories, Arkhangelsk, Vologda, Kirov, Kostroma, Kurgan, Tomsk and Tyumen Regions, as well as the Republics of Buryatia, Altai, Udmurtia and Karelia. In these territories, the number of infected patients significantly exceeds the Russian average of 2.18 per hundred thousand inhabitants.
AT Nizhny Novgorod region, the situation is as follows: from April 1st, 2014 health care in connection with the suction of ticks was provided to two thousand two hundred thirty-eight residents of Nizhny Novgorod, and according to the results laboratory research fourteen ticks out of one thousand nine hundred and seventeen examined individuals contain the antigen of the tick-borne encephalitis virus.

Thus, the risk of infection in the spring-summer period with infectious diseases carried by ticks is quite high, and every year statistics show a negative trend in this regard. The most characteristic carriers are the taiga tick (Ixodes persulcatus), the dog tick (Ixodes ricinus) (carries the virus of the western form of TBE), Dermacentor silvarum (common in the Far East).

It is worth noting some more transmissible viral diseases, such as Omsk and Crimean hemorrhagic fevers.

Omsk hemorrhagic fever- acute viral disease, in the transmission of which blood-sucking mites also participate. The infection penetrates through broken skin at the site of a tick bite or small wounds upon contact with a muskrat or water rat, which are the natural reservoir of the pathogen. The main carriers of ixodid ticks are Dermacentor pictus, Dermacentor marginatus. The disease is characterized by a hemorrhagic rash, headaches and muscle pains, nasal, pulmonary, intestinal bleeding is possible, blood vessels, kidneys and nervous system. Etiotropic (directed to the cause) treatment has not yet been developed.

Crimean hemorrhagic fever Caused by the so-called Congo virus. It is characterized by fever, severe intoxication, up to infectious-toxic shock, and hemorrhages on the skin and internal organs. The reservoir in nature is wild mammals, livestock, birds. Carriers - ticks Hyalomma marginatus, Ixodes ricinus, Dermatcentor marginatus. In Russia, outbreaks of this infection are observed in Astrakhan, Rostov, Volgograd regions, Crimea, in Stavropol, Krasnodar region, Dagestan. Kalmykia. Found in Ukraine Central Asia, in Africa. Treatment is etiotropic and symptomatic, various immunoglobulins are used.

Continuing the list of diseases carried by ticks, it is also worth noting ixodid tick-borne borreliosis (ICD), also called Lyme disease, tick-borne erythema, systemic tick-borne borreliosis. It is also a natural focal infectious disease belonging to the group of spirochetosis, bacterial etiology, transmissible. It can turn into a chronic or recurrent course and affect the brain, heart, liver, eyes, joints. It is caused by Borellia from the family of spirochetes contained in the intestines of the carrier tick. In the patient's body, it is excreted from the blood, CSF, synovial fluid. The infection is widespread in the USA, Canada, most of Europe, also in Russia, Mongolia. Japan and several other countries. The peak incidence usually falls on the spring-summer (April-June) and summer-autumn (August-October) periods. The disease can occur in three stages, differing in duration and severity of the course, as well as characteristic symptoms. Treatment is carried out with antibiotics and restorative drugs. The already mentioned dog and taiga ticks, as well as the black-legged tick (Ixodes scapularis) and Ixodes damini, which are found in the USA, may be involved in the transmission of Lyme disease.

The bites of a chicken tick that lives in poultry houses, when attacked by a person, can cause acute dermatitis.

Also, ticks are involved in the transfer of pathogens of such infections as erlichiosis. It is caused by erlichia, a bacteria related to rickettsiae. They are distributed mainly in the USA and Japan. There are two epidemiologically and etiologically different forms: monocytic and granulocytic human ehrlichiosis. Clinically, they are practically indistinguishable, characterized by head and muscle pain, chills, fever, decreased levels of platelets and leukocytes. Flow from mild to severe. Treatment with antibiotics.

Another infection, also probably known to many, is tularemia. This infection is typical for Russia, North America, Europe, Japan. It is transmitted by ticks, also by insects, or by contamination with sick and dead animals, with contaminated water and food. Symptoms are fever, night sweats, pain, swelling and often suppuration of the lymph nodes. There are different forms - intestinal, bubonic, pulmonary, etc. Mortality is low, treatment with antibiotic therapy.

also in last years on the territory of Russia are marked new forms of tick-borne fevers- the so-called Kemerovo and Lipovnik fevers. The first is typical, as the name implies for the Kemerovo region, the second is described for a number of European countries. Called by arboviruses. Reservoir - small mammals, birds. The main vectors are ixodid ticks of the genus Dermacentor. The clinic is expressed by fever, intoxication, rash, hemorrhages, sometimes signs of meningoencephalitis.
Some ticks from the superfamily Argazidae can also play a significant role in the transmission of dangerous infections to humans. About 12 species of them attack humans under certain conditions, these are the genera Argas and Ornithodorus. Their bites cause an itchy, red rash. The saliva of argas mites contains potent toxins. For example, the population of Mexico is very afraid of the attacks of the tick Ornithodorus coriaceus no less than rattlesnakes, since its bites are extremely painful. An interesting fact is that in the Khan's Bukhara, argases multiplied in such innumerable quantities (for example, in prisons and "bug pits") that some prisoners were simply sucked to death by hordes of hungry ticks.

Among the dangerous argazids, it is worth highlighting the Caucasian tick, which is involved in the transfer of the tick-borne relapsing fever we have already considered, as well as the Persian tick, the shell tick, and the village tick, which carries the tick-borne relapsing encephalitis.

In some individuals of ticks and their larvae, causative agents of several diseases present at the same time, such as tick-borne encephalitis and tick-borne borreliosis, or a combination of babesia and ehrlichi with viruses. When the host organism is infected with more than one infectious agent, so-called mixed infections occur, characterized by a significant increase in the severity of clinical manifestations, an increase in the number of symptoms and the duration of their course. The most common human mixinfection is babesia and Lyme disease pathogens.

Such short review the main dangerous infections that a person can become infected with through blood-sucking ticks. Obviously, in Russia, the risk of contracting one or more infections during the warm season is quite high. Their clinical diagnosis is difficult, and the laboratory is not always effective, especially in the early stages.

Measures aimed at improving them and involving in this process the latest data from epidemiology, ecology and zoology are priorities for health authorities around the world. Precautions and protection are quite simple: when visiting forests and meadows, use overalls, use repellents, and carry out self- and mutual examinations in a timely manner.

If a tick is found, you should immediately contact a specialist - a doctor - a therapist or an infectious disease specialist (it is undesirable to try to remove the tick yourself). It is advisable to conduct a study of the tick for the presence of possible pathogens in it, as well as to pass necessary tests. In general, be vigilant and observe the elementary aspects of prevention and protection, and then a walk in nature will not be overshadowed by a subsequent stay in an infectious disease hospital and a period of long rehabilitation.

Ixodid (ixodid) ticks - carriers of pathogens of piroplasmidoses (hemosporidiosis) of domestic animals, belong to the family. Ixodidae. Depending on the natural and climatic conditions, some ticks live mainly in the forest zone, others - in the steppe, and others - in the foothills, as well as in other zones.

The Ixodidae family includes six genera: Ixodes, Hyalomma, Dermacentor, Haemaphysalis, Rhipicephalus, Boophilus. In the territory Soviet Union There are over 50 species of ixodid, of which the majority are registered in the southern part of the country.

Biology of ixodid ticks. Usually, ixodid males fertilize females on the body of animals, which, after sucking blood, fall off, crawl into shelters and, depending on environmental conditions and the degree of blood saturation, lay from 4 thousand to 15 thousand eggs after 10-20 days, after which they die. Tick ​​eggs are relatively large (about 0.5 mm long), oval, yellow-brown in color, covered with a hard shell, immature. Eggs mature within a few weeks (up to a month or more). Through the resulting crack in the shell of the egg, a larva about 1 mm long hatches, having three pairs of legs and devoid of spiracles, genital opening and peritreme. To transform into the next stage (nymph), the larva must suck blood (more often on small wild animals and birds). The nymph has four pairs of limbs, but lacks a genital opening. After sucking blood (often in wild animals), the nymph detaches from the host and falls to the ground or turns into an imago on the body of the animal. Thus, for complete development from the egg to the sexually mature stage, ixodid ticks suck blood from several or one animal three times and molt twice. The duration of blood sucking by larvae is on average 3-7 days, by nymphs - 3-10 days, and by adults - 8-10 days. Most ticks overwinter in external environment at different stages of development. Depending on the type of development and mode of nutrition, ixodid are divided into single-host, two-host and three-host.

Single host mites all three active stages metamorphosis takes place on one animal, and only adults leave it to lay eggs in the external environment (Boophilus calcaratus, Hyalomma scupense).

Two-host mites in the stage of larvae and nymphs live on one host and in the imaginal stage - on the other (Rhipicephalus bursa, Hyalomma plumbeum, Hyalomma detritum).

Tri-host mites successively change three hosts, and the transformation of one stage into another always occurs in the external environment. This type of development is typical for most ixodid ticks (Ixodes ricinus, Dermacentor pictus, etc.).

Larvae and nymphs of two-host and three-host ticks prefer to attack mouse-like rodents, birds, less often reptiles, while adult ticks, as well as larvae of single-host ticks, attack domestic and large wild animals (roe deer, wild boars, etc.).

Genus Ixodes (trailer). Representatives of this genus have a long proboscis with a quadrangular base. The eyes are missing. Cokes I are not split. Anal groove in front. In males, the entire ventral surface is covered with scutes (Fig. 63). The dorsal scutellum, limbs and proboscis are dark brown, the cuticle of females is grayish yellow. Ixodes ricinus and Ixodes persulcatus are widespread on the territory of the USSR. They develop according to the three-host type, moisture-loving.

Ixodes ricinus is one of the most common ixodid ticks. It is found in the greatest quantity in the northwestern and central regions of the USSR; it is almost absent in the steppe and semi-desert zones. During the year, 1 generation develops. Ticks are able to starve for more than two years. Imago attack animals in spring and autumn. It is a carrier of Babesia bovis, Francaiella caucasica and Anaplasma marginale.

Ixodes persulcatus is distributed mainly in the taiga zone of Siberia and the Far East, as well as in the regions of Karelia and Leningrad region. Imago attacks animals in the spring-summer period (no later than July). This mite carries Babesia bovis and Francaiella caucasica.

Representatives of this genus are carriers of pathogens of piroplasmosis and nuttalliosis, theileriosis, as well as anaplasmosis in cattle.

Genus Haemaphysalis (bloodsucker). These are relatively small mites that have a short proboscis with a quadrangular base, unsplit coxae I, and an anal groove behind the anus. Ticks of this genus lack eyes and ventral scutes in males. Ticks are found in the steppe and forest-steppe zones, as well as in the foothills. The development of one generation lasts more than a year. Three-host mites Haemaphysalis otophila and Haemaphysalis puncata, which are carriers of Piroplasma bigeminum, Piroplasma ovis and Theileria annulata, are of veterinary importance.

Genus Rhipicephalus (fanheads). Heat-loving, relatively small red-brown mites, they have a short proboscis with a hexagonal base. They have eyes, split coxae I, a groove located behind the anus, and two pairs of central scutes in males (Fig. 66). Ticks are common in the North Caucasus, Transcaucasia, Crimea and Central Asia (in foothill and steppe regions). Animals are attacked in the spring-summer period of the year. Within a year, the development of one generation of ticks ends. The most common species of this genus are the two-host tick Rhipicephalus bursa (the main vector of sheep piroplasmids) and the three-host tick Rhipicephalus turanicus (the vector of NUttallia equi, Anaplasma rossicus, Anaplasma ovis N).

Features of methods of dealing with ixodid ticks

Destruction of ticks on animals

Manual collection of ticks. Collect and destroy ixodid ticks from cows of milkmaids, and from horses - sleds and grooms during the cleaning of animals. When collecting ticks, one should take into account the places of their favorite localization. For example, Rhipicephalus bursa ticks are more likely to attach themselves to sheep in the auricles, on the breast, in the groins and under the tail; Boophilus calcaratus - in cattle, mainly on the skin of the udder, scrotum, perineum, groin and dewlap; ticks of the genus Dermacentor - in horses in the intermaxillary space and at the base of the mane.

Ticks collected from animals should not be crushed by hand in order to avoid infection with some dangerous diseases; they are placed in a jar of kerosene. This method has limited application due to the high labor intensity and low labor productivity, as well as low efficiency (in most cases it is possible to detect and collect only well-fed female ticks).

Destruction of ticks chemicals - a widely used method in production conditions. To combat ticks on the body of animals use wet method(bathing in baths, spraying, wiping), and in the winter season - a dry method (treatment of the skin with dusts of acaricidal agents). The most effective and widely used in the fight against ixodid is the wet method of anti-tick treatment of livestock.

In the form of solutions, emulsions and suspensions, the following acaricides are prescribed for the treatment of the skin of animals (with an interval of 6-7 days):

1) 1% solution of chlorophos - 1-3 liters of solution for each animal;

2) Sevin suspension (0.75-1%) - 1-3 liters per animal;

3) 3% polychloropinene emulsion (only for young cattle) - 1.5-3 liters of emulsion per animal (rarely used);

4) 2% emulsion of the preparation SK-9 (dairy cows and slaughter animals must not be treated) - up to 3 liters (depending on the age and weight of the animal);

5) 1% emulsion of trichlormetaphos-3 (only young cattle can be treated) - 1-2 liters of emulsion per animal (no later than 60 days before slaughter);

6) sodium arsenite with different concentrations of arsenic anhydride (A2O3) for different types of animals (0.16% for bathing cattle, 0.18% for bathing sheep and 0.24% for wiping horses).

Sometimes, for the destruction of ixodid in animals, a 0.5% solution of chlorophos in a 0.1% solution of caustic alkali is used.

Of the ixodid ticks, representatives of the genus Ixodes are the most resistant to acaricidal agents, and mites of the genus Boophilus (especially larvae) show minimal resistance. The remaining ixoids occupy an intermediate position. In ticks of the same genus, males die faster from acaricides, as well as hungry ticks (at all phases of development).

Bathing animals in bathtubs characterized high efficiency. Animals are bathed in the warm season. In veterinary practice, stationary (bath-pools) and portable (metal, wooden and canvas) baths are used. The most widespread in collective farms and state farms are stationary baths-pools, arranged on a flat, dry site, away from roads and buildings. They are trenches with a concrete bottom and walls. Dimensions of a typical cattle bath: bottom length 7 m, waterline length (liquid level in the bath) 14 m, bottom width 0.6 m, waterline width 1 m, depth from bottom to liquid level 1.85 m, the height of the sides above the waterline is 0.5 m. The entrance platform is arranged at an angle of 45 ° (sliding), and the exit ladder is at an angle of 20 ° (5 m in length). The length of the entrance corridor is 3-5 m, the width is 0.8-1 m. A cemented platform adjoins the exit side of the bath, along which the liquid flowing from the animals enters the bath. To the side of the bath there is a sump connected to the bath by a pipeline with a valve. In front of the entrance and exit from the bath, cattle pens are arranged. This bath is designed for approximately 20 thousand liters of acaricidal liquid. You can also bathe sheep in it.

The liquid level in the bath is measured with a water meter, and the length and width of the bath with a tape measure. A few days before mass bathing, the good quality of emulsions or solutions of acaricides is checked on a small group of low-value animals. Young animals and weak animals are bathed separately. Animals should be watered before bathing. You can not bathe animals in rainy weather and during the hot hours of the day.

After bathing 300-600 heads of cattle, an emulsion or solution of an acaricidal preparation is added to the bath to the original volume. Replace the acaricidal liquid and remove impurities from the bath after bathing 2500-3000 animals. Of domestic animals, it is most convenient to bathe sheep (Fig. 68). Pregnant cows, ewes, sows and young animals up to 6 months of age are not bathed, but carefully sprayed with acaricidal preparations. In order to mechanize the bathing of sheep on farms, a Dokuchaev bath with a tilting platform is used.

Treated animals are placed in ventilated rooms or pens protected from sun rays and wind. Currently, manual bathing of animals is of limited use due to the high labor intensity and low labor productivity.

Spraying and wiping animals used in farms with a small number of livestock, in the absence of baths, which often occurs in the central and northern regions of the country, as well as for the destruction of ixodid ticks in pregnant and weak animals and in young animals up to six months of age. For spraying and rubbing, veterinarians successfully use solutions, emulsions and suspensions of the above drugs.

Large animals (large cattle, horses, camels) it is convenient to desacarize in showers ( automatic feed acaricide). Often, animals are sprayed in fenced areas using machines (DUK, LSD-2, VMOK-2, EMSOZH, etc.). During the processing period, animals are fixed in a split or in a machine.

Manual sprayers (hydraulic panels of various systems, etc.), as well as manual wiping of animals, are of limited use due to their low productivity. After treatment of the skin with acaricides before milking in cows (and also in mares), the udder is washed with water. Until the skin is completely dry, animals are not driven out to pasture.

People working with dusts must wear rubber or canvas gloves, goggles and gauze bandages over the nose and mouth. After the end of dusting, the animals carefully remove the remains of the dust from the ground or from the floor, and the udders of dairy cows are washed with soap.

Destruction of ticks in the premises

Livestock buildings in the south of the country are often inhabited by some species of ixodid ticks. There are especially many ticks in unimproved cowsheds and barns (in cracks in walls, pillars, ceilings, floors, feeders, in loose material on the floor, under feeders and other places). A radical method for the destruction of ticks in the premises is the elimination of their habitats: acaricide dust is poured into cracks and crevices, followed by their putty with cement or lime with clay; rodent burrows clog broken glass, stones, cover with cement; do not allow accumulations under the feeders and in the corners of the premises of food residues and debris. After mechanical cleaning of the premises, the pillars, the floor, the outer surfaces of the feeders are periodically moistened with a 1% suspension of sevin (200 ml of liquid per 1 m2), a 1.5% solution of chlorophos (2 l per 10 m2 of area), as well as other acaricides (including in the form of aerosols).

Sometimes, in the fight against ixodides in livestock buildings, acaricide aerosols are used, obtained by burning checkers (NBK-G17) and with the help of aerosol generators (AAG, AG-L6). Checker NBK-G17 (authors Nabokov, Burlyai and Kazakova) cylindrical shape, contains 1 kg of technical hexachlorane and 1 kg of thermal mixture. To obtain an aerosol in the form of smoke, the fuse of the checker is lit, after which it smokes heavily for 20 minutes. When the thermal mixture burns, the acaricidal agent is sublimated, which, on contact with colder air, condenses, forming smoke. Smoke has a greater permeability and, consequently, acaricidal effectiveness in comparison with oil aerosols (fog). Before using aerosols, animals are taken out of the premises, all holes in the walls, doors and windows are covered with clay. Checkers are placed on sheets of iron or earth (fire prevention measures) and lit, and the doors are closed.

The required concentration of aerosol (smoke) in the room can be created by burning a certain number of pellets (at the rate of 4-5 g of the drug per 1 m3). The sediment formed on the floor after the combustion of the checkers retains acaricidal activity for up to five days (during this period, cattle are not driven into the room).

Destruction of ticks in nature

Ixodid ticks lay their eggs on the ground, with some ticks choosing wet places for laying, others dry, and still others forest. If these conditions are violated, then the eggs of ticks and the ticks themselves often die. To disturb the habitat of ticks in natural conditions and in order to destroy ticks at different stages of development, they carry out isolation and change of grazing areas, agricultural activities (plowing of virgin lands, reclamation of swampy pastures, weeds and weeds in autumn and spring, the destruction of mouse-like rodents), use chemical methods, as well as natural enemies of ticks.

Isolation and grazing change used in the fight against ticks Boophilus calcaratus, as well as Rhipicephalus bursa, which feed only on domestic animals. The main requirement when changing pastures is to keep domestic animals away from the ticked area of ​​the pasture for the period during which the ticks die of starvation (Boophilus calcaratus after 6-7 months, Rhipicephalus bursa after ten months). If you graze cattle on each plot for 25 days (the development of the Boophilus calcaratus tick from larva to sucking female takes 21-24 days) with a return to the previously used site after seven months, you can free the pasture area from ticks of this species in one year.

The alternation of lowland (winter) and mountain (summer) pastures in the south of the country plays big role in the fight against ticks Boophilus calcaratus and Rhipicephalus bursa. It is necessary to move cattle in the spring to subalpine pastures before the activation of ticks (cattle in early April, and sheep no later than mid-May). Against most ixodid ticks, changing pastures is ineffective, since these ticks are able to starve for a longer time (more than one year) and can feed not only on domestic, but also on wild animals.

Chemical Methods control of ticks in natural conditions is sometimes carried out by spraying dusts of acaricides with the help of helicopters and airplanes, and in limited areas - with the help of special dusters.

natural enemies ticks. Noteworthy is the insect of the riding (Hunterellus hookeri), the female of which lays up to 20 eggs in the body of ixodid tick nymphs. The larvae hatched from the eggs of the rider cause the death of ixodids (only the chitinous shell of the tick remains). A significant number of ixodids are eaten by birds, as well as lizards; mold fungi are dangerous for them, the hyphae of which penetrate the body of ticks.

To the question Encephalitic tick? Natural enemies of ticks? Where are they most common? Why there? given by the author I-beam the best answer is Ticks are one of the most diverse and ancient groups of arthropods on Earth. Typically, mites feed on plant debris, soil fungi, or other small arthropods. There are more than 40,000 species of ticks in the world fauna, however, many groups are still poorly understood, and dozens of new species are described annually by scientists. Some mites have adapted to feeding on the blood of animals and have become parasites. Among the parasites, the most famous ixodid ticks (Ixodoidea). This group has only 680 species that live on all continents, including Antarctica. Ixodid ticks carry human pathogens with natural foci: tick-borne encephalitis [the main carriers are the taiga tick Ixodes persulcatus and I. ricinus], tick-borne borreliosis (Lyme disease), tick-borne typhus, relapsing tick-borne fever, hemorrhagic fever and Q fever, tularemia, ehrlichiosis, and many others. A number of measures are taken to protect against the bites of Ixodid ticks.
Despite a significant number of species of ixodid ticks, only two species are of real epidemiological significance: Ixodes Persulcatus (taiga tick) in the Asian and in a number of areas of the European part, Ixodes Ricinus (European forest tick) in the European part. In the future, we will talk about these types of ticks.
The taiga and European forest ticks are giants compared to their "peaceful" counterparts, its body is covered with a powerful shell and equipped with four pairs of legs. In females, the integument of the back is able to stretch greatly, which allows them to absorb large quantities blood, hundreds of times more than a hungry tick weighs. Males are slightly smaller than females and only suck on a short time(less than an hour). To distinguish between a female and a male is very simple - you need to remember how they look.
In the surrounding world, ticks are guided mainly by touch and smell; ticks do not have eyes. But the sense of smell of ticks is very acute: studies have shown that ticks are able to smell an animal or a person at a distance of about 10 meters.
Tick ​​habitats. Ticks that transmit encephalitis are distributed almost throughout the southern part of the Eurasian forest zone. Which places are most at risk for ticks? Ticks are moisture-loving, and therefore their number is greatest in well-moistened places. Ticks prefer moderately shaded and moist deciduous and mixed forests with dense herbage and undergrowth. There are many ticks along the bottom of dens and forest ravines, as well as along forest edges, in thickets of willows along the banks of forest streams, etc.