There are over 50,000 species of ticks. They are divided into herbivorous and pathogenic. Few people know that these arthropods are not only carriers of various infections, but also pests, since they cause damage agriculture and the food industry.

Most of the ticks are saprophages (predators) that benefit by killing other pests. They also feed on soil organic matter, which contributes to its decomposition to humus.

What types of ticks do not benefit, but harm nature

The first signs of ticks on garden plot are

• cobweb on plantings;
• growths;
• fuzzy light spots.

This indicates that the trees are under threat of destruction.

There are several types of mites, some of them are partial to conifers and shrubs such as boxwood or pine. There are varieties of these arthropods that live only on broad-leaved trees. In nature, there are superfamilies of garden herbivorous mites

• gallic;
• brown;
• spiderweb.

They settle on fruit and berry crops.

Garden mites are small arachnids. Males are smaller than females, their length is from 0.03 mm to 10 mm. The body is divided into two parts, the abdomen and the cephalothorax. It has a round shape and is covered with bristles. The tick has two pairs of eyes. It moves with the help of 6 pairs of appendages. The juice from plants and fruits is sucked out with the help of a piercing-sucking mouth apparatus.

More than 1200 species in nature spider mites... This is very small insects leading a hidden lifestyle. Males range in size from 0.3 mm to 0.6 mm, and females up to 1 mm. You can find out the defeat of this type of mite by changing the color of the leaves on the plant, which become brown-brown. Then they curl up and fall off. This type of pest can destroy 80% of the crop. He is also a carrier of gray rot and various viral infectious diseases of agricultural plants.

Gall mites differ from other counterparts in the absence of hind legs. Most often, this variety can be found on cherry plum, plum and pear. Growths are formed on the leaves of trees, where the tick lives. The affected branches are cut and burned.

The brown tick mainly settles on horticultural crops... Most often it can be seen on apple trees. The color is red-brown. This species reproduces very quickly. By the end of summer, the tree is full of pests that dehydrate it. As a result, the apple tree dries up.

The benefits and harms of ticks

Ticks can be found everywhere, even in Antarctica. They live both on land and in water bodies. They can travel long distances despite their diminutive size. They are mainly found in bird nests, burrows, in residential and commercial premises. Some species even live under the skin and in the respiratory system of mammals.

But not all species are hazardous to crops or humans. There are groups of mites that provide tangible benefits.

• Exterminate plant pests.
• Recycle their remains.
• Participate in the process of soil formation.

There are types of these arthropods that are used to make certain types of cheese. But this is where the benefits of ticks in nature end.

Thus, the tick, despite the small list of positive properties, is an irreplaceable link in nature. It serves as an excellent food for birds, frogs, lizards, ants.

In the fight against them, biological agents are practically useless, since ticks multiply very quickly. Therefore, a person has to apply chemicals to protect crops, plantations and their health.

The tick (Acari) is one of the oldest inhabitants of our planet. Contrary to the erroneous opinion, ticks are not insects, but are representatives of the order of arachnids.

Description of ticks. What does a tick look like?

In size, these representatives of arthropods rarely reach 3 mm, in general, the size of ticks ranges from 0.1 to 0.5 mm. As befits arachnids, ticks lack wings. Adult ticks have 4 pairs of legs, while specimens that have not reached puberty have three pairs of legs. Without eyes, ticks orient themselves in space with the help of a well-developed sensory apparatus, thanks to which they can smell the victim 10 meters away. According to the structure of the body, all types of ticks can be divided into leathery ones, with accrete head and chest, and solid (armored), in which the head is attached to the body movably. Oxygen supply also depends on the structure of the body: the former breathe through the skin or trachea, while the armored ones have special spiracles.

What do ticks eat?

By the way of nutrition, ticks are divided into:

• saprophages feeding on organic residues

Predators of blood-sucking ticks wait for the prey, settling in ambush on blades of grass, twigs and sticks. With the help of paws equipped with claws and suction cups, they attach to it, after which they move to the place of feeding (groin, neck or head region, armpits). Moreover, the victim of a tick can be not only a person, but also other herbivorous ticks or thrips.

A tick bite can be very dangerous, as ticks are carriers of diseases, including encephalitis. Ticks can do without food for up to 3 years, but at the slightest opportunity they show miracles of gluttony and can increase in weight up to 120 times.

Types of ticks. Tick ​​classification

Ticks have more than 40,000 species, which scientists have divided into 2 main superorders:

Description of the main types of mites:

• Ixodidpincers

• Argasovye pincers

• Carapace mites

• Gamasid mite

• Subcutaneous mite

• Scabies mite

• Ear mite

• Dust mite (bed, linen)

It is absolutely harmless to birds, animals and humans, as it is a complete “vegetarian” and feeds on plant juices, settling from the lower part of the leaf and sucking the juices out of it. It is a carrier of gray rot harmful to plants.

• Water (sea) mite

It feeds on its congeners, therefore, sometimes a person deliberately settles in greenhouses and greenhouses to combat spider mites.

• Barn (flour, bread)mite

For humans, in principle, it is safe, but for grain or flour reserves it is a serious pest: products are clogged with waste products of flour mites, which leads to rotting and the formation of mold.

lives in the southern part of Russia, Kazakhstan, Transcaucasia, mountains Central Asia, in the south of Western Siberia. It mainly settles in forest-steppes or forests. Dangerous for animals and humans, can be a carrier of encephalitis, plague, brucellosis, fever.

harmless to humans, but dangerous to dogs. Dwells everywhere. It is especially active in coastal areas and on the Black Sea coast.

Where do ticks live?

Ticks live in every climatic zone and on all continents. Due to the fact that ticks prefer wet places, they choose forest ravines, undergrowth, thickets near the banks of streams, flooded meadows, overgrown paths, animal hair, dark warehouses with agricultural products, etc. Separate types adapted for life in the seas and reservoirs with fresh water... Some ticks live in houses and apartments, for example, house ticks, dust mites, flour mites.

Spread of ticks

How long does a tick live?

The lifespan of a tick depends on the species. For example, ticks house dust or dust mites live 65-80 days. Other species, such as the taiga tick, live up to 4 years. Ticks can live from 1 month to 3 years without food.

Reproduction of ticks. Stages (cycle) of tick development

Most ticks are oviparous, although there are viviparous species. Like all arachnids, ticks have a clear division into females and males. The most ineresting life cycle tracked in blood-sucking species. The following stages of tick development are distinguished:

• Larva
• Nymph
• Adult

Mite eggs

In late spring or early summer, the female tick, saturated with blood, makes a clutch of 2.5-3 thousand eggs. What do mite eggs look like? The egg is a rather large cell in relation to the size of the female, consisting of cytoplasm and nucleus, and covered with a two-layer membrane, which is painted in various colors. Tick ​​eggs can be of completely different shapes - from round or oval, to flattened and elongated.

What do tick eggs look like?

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

Any species or taxonomic group of species should be considered only in conjunction with the features of their phylogenesis (origin), habitat, and relationships with other species of animals and plants. 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, ticks belong to the type of arthropods, the subtype of cheliceraids, the class of arachnids, a subclass of ticks, which currently numbers just over forty-eight thousand species.

Unfortunately, in recent years, 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 long, so we will limit ourselves to a brief excursion on the main points of their participation in processes in environment as well as in the human economy.

Blood sucking ticks

Greatest danger for humans and animals, they represent blood-sucking ticks, primarily in that they are able to preserve and transfer pathogens of a number of severe infections from animals to humans for a long time. It is they who, as a rule, are given the most keen interest in various kinds of 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 is most likely correct. If you really do it yourself, then it is most convenient to do this with small curved tweezers.

The tick is grasped as close to the proboscis as possible, and by sipping and rotating the tick around its own axis, it is removed together with the proboscis. You can use a thread loop by grabbing the tick as close to the head as possible. You should 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 the proboscis sticking out above the surface of the skin, it can be unscrewed with tweezers, or contact the surgeon at the clinic. You cannot cut or pick out 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 acariasis... Diseases that develop as a result of the transmission of the pathogen through blood-sucking arthropods (in particular ticks) are called transmissible. Distinguish between specific carriers, that is, those in the body of which the pathogen goes through some stage of its development (or multiplies), and mechanical, in which the infectious agent does not develop and does not multiply, but once on the oral apparatus or into 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-vector-borne diseases, such as leishmaniasis), or by other means (through animal products, through the respiratory system). Not all ticks acquire infectious agents through direct contact with them.

In 1940, academician E.N. Pavlovsky put forward the doctrine of the natural focus of diseases. According to him, these diseases are closely related to a complex of natural conditions and exist in the natural environment independently of a person. A natural focus is a specific geographic landscape in which the pathogen circulates from donor to recipient through a carrier. Pathogen donors are animals that have become ill with any vector-borne infection, or are a natural reservoir of the pathogen, without infecting the carriers themselves. Recipients of the pathogen are sick animals (or humans) that become donors after infection.

Thus, we see that the natural includes the following components:

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

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

Now let's move on to a more detailed consideration of various infectious diseases, pathogens, and their causative agents 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 are part of the families: Gamasoidea (gamasid ticks), Argasidae (argasidae), Trombidiidae (redling ticks), Ixodidae (ixodid ticks). Argasaceae and Ixodidae are united in 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 lack of food), and for others, a person serves as an ordinary victim.

Russia, due to the vastness and heterogeneity of its territories, is one of the world's largest areas for infectious diseases carried by ticks. In general, they spread over 20 infectious diseases on the territory of the CIS.

One of the most dangerous infections transmitted to humans with the help of ixodid ticks are various encephalitis.
In more broad 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, often fatal outcomes, especially with 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 get it by eating raw cow's or goat's milk (alimentary route). The incubation period is 5-25 days, with alimentary penetration 2-3 days. Has three main genotypes of the virus - Far Eastern, Western, and Ural-Siberian.
The disease begins acutely, there is a chill, fever up to pyretic and hyperpyretic levels, severe headache (cephalgia), myalgia, lethargy, drowsiness, less agitation. The skin of the face, neck, and rather of the body is hyper-hypertensive.

It usually proceeds in the form of three forms: febrile, meningeal (with the addition of meningeal signs) and focal (characterized by convulsions, impaired consciousness), and the latter is characterized by high mortality. This disease has several characteristics that are specific to it. One of them is severe damage to the nervous system, expressed by paralysis and paresis of the neck and upper extremities, muscle atrophy, and also in some cases of Kozhevnikovskaya epilepsy syndrome. Also characteristic feature CE is the possibility of developing a chronic progressive process, almost invariably leading to lethal outcome... Currently, there is no radical treatment for the effects of CE. But you can nevertheless protect yourself from this formidable disease 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 the data of Rospotrenadzor 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 the body of which the causative agent of this infection is directly isolated.

Among the leading regions in terms of the incidence of this disease are the Perm and Krasnoyarsk Territories, the 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 average for Russia, 2.18 per hundred thousand inhabitants.
In the Nizhny Novgorod region, the situation is as follows: from April 1, 2014 health care in connection with the suction of ticks, two thousand two hundred and thirty-eight residents of Nizhny Novgorod were given, and according to the results laboratory research in fourteen ticks out of one thousand nine hundred and seventeen individuals studied, the antigen of the tick-borne encephalitis virus is contained.

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

It is worth noting some more vector-borne viral diseases, such as the Omsk and Crimean hemorrhagic fevers.

Omsk hemorrhagic fever- an acute viral disease, in the transmission of which blood-sucking ticks are also involved. The infection penetrates through the damaged skin at the site of the tick bite or small wounds upon contact with the muskrat or water rat, which are the natural reservoir of the pathogen. The main vectors are ixodid ticks 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 (targeting 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 the countryside - wild mammals, livestock, birds. Carriers are mites Hyalomma marginatus, Ixodes ricinus, Dermatcentor marginatus. In Russia, outbreaks of this infection are noted in the Astrakhan, Rostov, Volgograd regions, Crimea, in the Stavropol, Krasnodar territories, Dagestan. Kalmykia. Found in Ukraine, Central Asia, Africa. Treatment is etiotropic and symptomatic; various immunoglobulins are used.

Continuing the list of diseases carried by ticks, it is worth noting also ixodic tick-borne borelliosis (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 spirochetoses, bacterial etiology, transmitted by transmission. It can turn into a chronic or recurrent course and affect the brain, heart, liver, eyes, joints. It is caused by borellias from the spirochete family, which are found in the intestines of the host tick. In the patient's body, it is excreted from the blood, CSF, synovial fluid. The infection is widespread in the United States, Canada, most of Europe, also in Russia, Mongolia. Japan and several other countries. The peak incidence usually occurs in the spring-summer (April-June) and summer-autumn (August-October) periods. The disease can proceed in three stages, differing in the duration and severity of the course, as well as in characteristic symptoms. Treatment is carried out with antibiotics and restorative drugs. The already mentioned canine and taiga ticks, as well as the black-footed tick (Ixodes scapularis) and Ixodes damini found in the United States, can participate in the transmission of Lyme disease.

Bites chicken tick living in poultry houses when attacking a person can cause acute dermatitis.

Also, ticks are involved in the transfer of pathogens such as ehrlichiosis... Caused by ehrlichiae, a bacterium related to rickettsia. Distributed mainly in the USA and Japan. There are two distinct epidemiologically and etiologically forms: monocytic and granulocytic human ehrlichiosis. Clinically, they are practically indistinguishable, characterized by headache and muscle pain, chills, fever, and a decrease in the level of platelets and leukocytes. Light to severe course. Antibiotic treatment.

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 insects, or by contamination with sick and dead animals, with contaminated water and food. Symptoms are fever, night sweats, talking pain, enlargement and often suppuration of the lymph nodes. Distinguish different shapes- intestinal, bubonic, pulmonary, etc. Lethality 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 suggests, for the Kemerovo region, the second is described for a number of European countries. Called by arboviruses. Tank - 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 argaz superfamily can also play a significant role in the transmission of dangerous infections to humans. About 12 species of them, under certain conditions, attack humans, these are the genera Argas and Ornithodorus. Their bites cause itching, red rash. Argas mite saliva contains potent toxins. For example, the population of Mexico is very afraid of attacks by the tick Ornithodorus coriaceus no less than rattlesnakes, since its bites are extremely painful. An interesting fact is that in Khan Bukhara, argazaceae multiplied in such myriad 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, which we have already considered, as well as the Persian tick, the shell tick, as well as the village tick, which carries tick-borne recurrent encephalitis.

In some individuals, ticks and their larvae can simultaneously present causative agents of several diseases, for example tick-borne encephalitis and tick-borne borelliosis or a combination of babesia and ehrlichia 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. Most often, people are mixed with babesia and the causative agents of Lyme disease.

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

Measures aimed at improving them and attracting the latest data from epidemiology, ecology and zoology to this process are priorities for health authorities around the world. Precautions and protection are quite simple: when visiting forests and meadows, use overalls, use repellents, and timely self-check and inspect each other.

If a tick is found, you should immediately contact a specialist - a doctor - therapist or 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 pass the necessary tests. In general, be vigilant and observe the elementary aspects of prevention and protection, and then a walk into nature will not be overshadowed by a subsequent stay in an infectious diseases hospital and a period of long rehabilitation.

Most people associate ticks with dangerous bites, infectious diseases and other troubles. But, like any living organism in the ecosystem of our planet, nature needs mites. From the point of view of biological balance, these arachnid benefits bring almost more than harm.

The greatest danger to humans is represented by ixodid ticks, which feed on blood and are carriers dangerous diseases... At the same time, these arachnids are irreplaceable in the ecosystem, since they play the role of a regulator of natural selection. Weak animals die after being bitten by such a tick, giving way to the strongest, and those, in turn, develop immunity. Thus, in nature, the numerical balance of individuals is maintained.

Here is a vivid example of how an obvious benefit to nature, at the same time, has an extremely negative effect on humans. Therefore, the question of the benefits and harms of ticks needs to be considered in more detail, because the answer to it is completely ambiguous.

Are ticks useful?

The concept of "benefit", of course, is inseparable from human culture, therefore, despite the prejudice of people towards ticks, the latter provide tangible help in various industries.

In addition, mites are an important link in the ecological system, helping to make natural selection and maintain balance, and they are also part of the food chain, for example, birds and frogs gladly eat ixodid ticks.

What harm do they do?

The most dangerous for both people and animals are. And in the first place among them is the taiga (encephalitis) tick, which is a carrier of encephalitis, borreliosis, ehrlichiosis and other equally dangerous diseases. Since these arthropods feed exclusively on blood, infection occurs after a bite, viruses and pathogens of terrible diseases enter the victim's body along with saliva.

In addition to blood-sucking arachnids, human health can be threatened by subcutaneous, scabies and other mites, which are carriers of such unpleasant diseases as scabies, dermatitis and others.

Why are mites needed in nature? Apparently then, in order to occupy a clearly assigned ecological niche and to fulfill their direct duties that have appeared in the process of evolution.

What are mites for in nature?

Ticks help natural selection and play no less important role in the process of evolution. Who can survive after a tick bite is considered a strong individual and acquires some immunity and knowledge. The strongest survive, and ticks help to identify the strongest.

In nature, mites are an integral part of the food chain. They are very fond of ants and they eagerly eat them. Ixodid ticks serve as a delicacy for such a family of beetles as ground beetles.

So it’s impossible to say that ticks only suck blood and spread disease. They are eaten, received from them nutrients other animals.

And the biologist andryukha and I think that ticks are not needed for anything, appendicitis is also not particularly needed. Here are the ticks, whether they are there or not - this is just the imperfection of nature. By the way, I'm a doctor

In nature, everything exists for a reason, but for a purpose.

So the mites, which live mainly on animals, feed on the dead parts of the skin. It turns out that they cleanse the skin in this way.

Well, I think that ticks are needed in order to destroy already sick animals. This is natural selection. As on the whole planet, a hare eats grass, a wolf eats a hare, well, something like that. Well, I still have a version. There is a macro and a micro world. Ticks, when bitten, inject microbes into the bloodstream, the body of that animal begins to secrete antibodies that begin to kill these microbes. Or maybe even some new organism appears in the environment. They cross and get a new organism inside one big one. Although I am not a biologist, I will not argue.

Most likely, there is a scientific explanation for any fact, but in nature nothing happens just like that. If there are ticks, then they are needed for something. As a complacency, I believe that their disappearance may give rise to an invasion of other, more dangerous creatures, maybe the existence of ticks prevents something more terrible.

If you approach from a scientific, evolutionary point of view, then there is nothing. It's just that this type of organisms is quite adapted to survival, therefore, having once accidentally formed from some other, it continues to exist to this day.

And if you approach with a religious one, then there may be different variants tick application:

1 For example, to punish a sinner or by striking him, to prevent the atrocities he is planning.

2 Send the righteous man who is unjustly tormented on Earth to paradise as soon as possible.

3 Slay one animal so that several others are fed with its body.