How ticks reproduce - stages of development and features

Valentin Vlasov, Vera Rar, Sergey Tkachev, Nina Tikunova “Science at First Hand” No. 5/6(85), 2019

The composition uses a photo of a female ixodid tick, Amblyomma cajennense,

, carrier of Rocky Mountain spotted fever pathogens

Every year, hundreds of thousands of people visit medical institutions due to a tick bite. For these blood-sucking parasites, humans are only incidental “prey,” but ticks serve as carriers of a whole arsenal of pathogens that cause diseases in humans and animals. Anyone who spends time in nature, including our pets, can face the problem of tick-borne infections; Farm animals also suffer from tick-borne infections. The purpose of this article is to better acquaint readers with the habits and lifestyle of ixodid ticks, primarily common in our country, which can carry about three dozen diseases, including tick-borne encephalitis and borreliosis. In recent years, the problem of tick-borne infections has been aggravated by the fact that the range of these ticks both in Russia and in other countries of the world is rapidly expanding.

About the authors

Ixodid ticks are found in all parts of the world, including islands and coasts of the Arctic and Antarctic, and in various climatic zones - from taiga to desert (Balashov, 1998). Among them there are both fairly “omnivorous” and highly specialized species that feed only on birds, chiropterans or small mammals (Estrada-Pena et al., 2017).

The main harm from ticks to host animals is associated with the direct parasitism of a large number of ticks on individuals, which can lead to high blood loss or severe intoxication as a result of parasite saliva entering the body. There are known cases of death of wild animals due to massive parasitism of ixodid ticks: wild antelope in the Zimbabwe National Park, young white-tailed deer in the USA, moose in Canada and the northern USA.

The incidence of ticks in farm animals can also be very high in the absence of special anti-tick treatment. Thus, one individual of cattle can simultaneously feed on several dozen, and several hundred ticks per season; the total blood loss is calculated in liters! Even cases of death of sheep as a result of several hundred ticks parasitizing them have been described (Balashov, 1998).

As for humans and their pets, such as dogs, the main danger of ticks for them is the high risk of infection in the event of even a single bite. Ixodid ticks carry pathogens of viral, bacterial and protozoal infections that can infect people. It is impossible to eradicate such diseases, since their foci exist in nature regardless of humans, and the vectors themselves are an integral part of natural ecosystems. And to protect yourself from ticks, you need to know the behavior and ecology of our potential “enemy”.

Ticks are often mistakenly called insects, but it is easy to distinguish a potential bloodsucker from a harmless bug: adult ticks have eight legs, like spiders, and not six, like insects.
Together with spiders, mites form the class of arachnids (Arachnida), which, along with crustaceans, insects and centipedes, is included in the phylum of arthropods (Arthropoda). Today, more than 50 thousand different types of ticks are known, and all of them are parasites, although not all pose a danger to humans or domestic animals. The tick family Ixodidae includes six main genera: Ixodes

(249 species),
Haemaphysalis
(166),
Amblyomma
(142),
Rhipicephalus
(79),
Dermacentor
(36),
Hyalomma
(25 species).
The Latin name of each tick consists of two parts: an indication of the genus and species, and well-studied species also have a Russian name. For example, taiga tick ( Ixodes persulcatus
), meadow tick (
Dermacentor reticulatus
).

Taiga tick Ixodes persulcatus

- the most common tick in Russia: its range extends from the northwestern regions (Leningrad region, Karelia) through the entire country to the Far East.
Inhabits taiga, forest and forest-steppe biotopes; found in the foothill forest-steppe and mountain forest belt up to an altitude of 2000 m (Filippova, 1977). Adults are active from early spring to mid-summer, larvae and nymphs are active throughout the warm season. Ixodes persulcatus
is the most dangerous for people, as it carries pathogens of the most severe forms of tick-borne encephalitis.
This species of tick is also a carrier of tick-borne borreliosis and relapsing fever ( Borrelia miyamotoi
) (Korenberg, 2013).
Infection can occur as a result of suction not only from females, but also from males who suction for a short time, and, in rare cases, nymphs. Male ( left
) and female (
right
) taiga tick
Ixodes persulcatus
. Photo by V. Panov (IS&EZh RAS, Novosibirsk) and S. Tkachev

Ixodid ticks are the largest of all ticks: adults reach 2–13 mm in length. The most common taiga tick in Russia, I. persulcatus

The body length of a hungry female is 3–4 mm, a male is 2–3 mm, a nymph is 1.2–1.7 mm and a larva is less than 1 mm. The size of engorged ticks is significantly larger

Features of reproduction

Before considering the usual process of reproduction of ixodid ticks, it is necessary to understand viviparity. This method of reproduction refers to only two types, it consists of the following. A fertilized female bears offspring within herself; when the eggs mature, she dies. Since this happens in the fall, the offspring overwinters in the mother's body. With the arrival of spring, when it gets warmer, the egg development stage ends and larvae appear.

They appear in the mother's body and begin to gnaw their way out, thereby satisfying hunger and obtaining the necessary nutrients for development. With this method of reproduction, the offspring receives much less nutrients, especially where the eggs are laid.

Now let's look at the usual method of reproduction for ticks. In fact, the fertilization process itself is not a complicated procedure; no preparation or special conditions are needed. The male individual looks for a female, attaches itself to her body with the help of suction cups on its paws, and fertilization occurs. Speaking of males, most often they die after mating, but if after the first mating there is another female nearby, then he can fertilize her too, and only then die. But between these processes he definitely needs to get enough blood.

These parasites also have an interesting feature. The fact is that the female is capable of laying eggs without the participation of a male. In other words, in order to lay offspring, she does not have to mate at all; egg laying will happen in any case. The only difference is that during mating, the offspring will be both male and female, and without it, only female.

Destruction of ticks on animals

In the fight against ticks parasitizing animals, mechanical (collecting ticks) and chemical methods (treating animals with dusts, solutions, emulsions, suspensions and aerosols of acaricidal preparations) are used. They are used for the extermination of ticks and for preventive purposes (bites and suction of these parasites and the disease of animals with protozoal and infectious diseases are prevented).

Manual collection of ticks.

Ixodid ticks are collected and destroyed from cows by milkmaids, and from horses by riders and grooms when cleaning the animals. When collecting ticks, you should take into account their favorite locations. For example, Rhipicephalus bursa mites often attach themselves to sheep in the ears, dewlap, groin and under the tail; Boophilus calcaratus - in cattle, mainly on the skin of the udder, scrotum, perineum, groin and dewlap; mites 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 to avoid infection with some dangerous diseases; they are placed in a jar of kerosene. This method has limited use due to its high labor intensity and low labor productivity, as well as its low efficiency (in most cases it is possible to detect and collect only well-fed female ticks).

Destruction of ticks by chemical means

- a widely used method in industrial settings. To combat ticks on the body of animals, a wet method is used (bathing in baths, spraying, wiping), and in the winter season - a dry method (treating the skin with acaricidal dusts). The most effective and widely used in the fight against ixodids is the wet method of anti-tick treatment of livestock.

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

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

2) sevin suspension (0.75-1%) - 1-3 liters for each animal;

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

4) 2% emulsion of the drug SK-9 (dairy cows and slaughter animals cannot be treated) - up to 3 l (depending on the age and weight of the animal);

5) 1% emulsion of trichlorometaphos-3 (only young cattle can be processed) - 1-2 liters of emulsion for each animal (no later than 60 days before slaughter);

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

Sometimes, to kill ixodids on 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 acaricides, while ticks of the genus Boophilus (especially the larvae) show minimal resistance. The remaining ixoids occupy an intermediate position. In ticks of the same genus, males, as well as hungry ticks (at all phases of development), die faster from acaricides.

Bathing animals in baths

characterized by high efficiency. Animals are bathed in the warm season. In veterinary practice, stationary baths (swimming pools) and portable baths (metal, wood and canvas) are used. The most widespread on collective and state farms are stationary bathtubs-pools, located on a flat, dry area, 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, width 0.8-1 m. Adjacent to the exit side of the bath is a cemented platform through which the liquid flowing from the animals enters the bath. On 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, there are corrals for livestock. 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 quality of emulsions or solutions of acaricides is checked on a small group of low-value animals. Young and weak animals are bathed separately. Animals should be given a drink before bathing. You should not bathe animals in rainy weather or during hot hours of the day.

After bathing 300-600 heads of cattle, an emulsion or solution of an acaricidal drug is added to the bath to the original volume. The acaricidal liquid is replaced and dirt is removed from the bath after bathing 2500-3000 animals. Among domestic animals, sheep are the most convenient to bathe (Fig. 68). Pregnant cows, ewes, sows and young animals under 6 months of age are not bathed, but are carefully sprayed with acaricidal preparations. In order to mechanize the bathing of sheep, farms use a Dokuchaev bathtub with a tilting platform.

Treated animals are placed in ventilated rooms or pens, protected from sunlight and wind. Currently, hand bathing of animals has limited use due to its high labor intensity and low labor productivity.

Spraying and wiping down 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 wiping, veterinarians successfully use solutions, emulsions and suspensions of the above drugs.

It is convenient to decontaminate large animals (cattle, horses, camels) in shower chambers (automatic supply of acaricide). Animals are often sprayed in fenced areas using machines (DUK, LSD-2, VMOC-2, EMSOZH, etc.). During the processing period, animals are fixed in a split or in a pen.

Manual sprayers (hydropolettes of various systems, etc.), as well as manual wiping of animals, have limited use due to their low productivity. After treating the skin with acaricides before milking, the udder of cows (as well as mares) is washed with water. Animals are not put out to pasture until the skin is completely dry.

Aerosols

used in the fight against ixodid ticks and insects on animals, indoors and on pastures. Aerosols are tiny droplets of liquid or small solid particles suspended in a gaseous medium. Aerosols with liquid particles are called mists, and aerosols with solid particles obtained by condensation are called fumes. An example of condensation aerosols is natural fogs. Aerosol particles have different sizes and shapes: in fogs they are spherical, and in smoke they have a regular crystalline shape. Aerosol particle size, i.e. the degree of its dispersion varies widely. A number of physicochemical properties of aerosols (evaporation, diffusion, sedimentation, etc.) depend on the size of the particles and their shape. In the fight against harmful arthropods, aerosols with a particle size of 0.1-1000 u are used in the form of oil mists (aerosol cans) and fumes (acaricidal bombs). Aerosols of acaricides and insecticides are more often used to kill parasitic arthropods indoors and on pastures and much less often on animals.

Treatment of animals with acaricide dusts

- a dry method of combating parasitic mites and insects, carried out mainly in the winter season. Dusts are a powdered form of insectoacaricides, in which the active substance is mixed in certain proportions with a neutral filler (talc, kaolin, ash, chalk).

Neutral, or indifferent, substances reduce the humidity of the air under the fur and absorb lymph on the surface of the skin, creating unfavorable conditions on the skin of animals for parasitic arthropods. Currently, dusts of sevin (7.5%), chlorophos (5-10%) and other acaricides are used. Decontamination of animals with dusts is carried out in walking areas or in rooms with good ventilation, in which there is no fodder. To apply dusts to the skin of animals, you can use special pollinators (OZHU-5) (this treatment is often carried out manually).

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

Life stages

Thousands of species of ticks live in nature, the life cycle of which goes through the following stages:

• a larva emerging from an egg;
• nymphs, development includes 4−8 molts;
• imago, or sexually mature tick.

Each reincarnation occurs after the parasite is fed with blood.

The duration of the stages varies from several days to months. While waiting for prey, diapauses or hibernation breaks occur, in which activity is reduced to a minimum.

The state of a kind of suspended animation allows you to survive any unfavorable period. The ability to slow down metabolic processes greatly increases the period of existence of the parasite.

The tick type, habitat, environmental features are the main factors influencing the life span and each of its stages

Gamasid mites

This type of mite occupies an average stage of development and is found mainly not as a parasitic species.

Link on topic

From this article you will learn more about gamasid mites.

Most of them live in black soil or manure. There are swamp, river and tree species. There is usually little talk about these ticks, since they do not cause much harm to humans. Many people don’t even know about their existence, but they surround every person in their thousands. All representatives of gamasidae are, as a rule, smaller than large ones, but there are specimens up to 4 mm in body diameter.

Despite their modesty in living conditions and culinary preferences, among the gamasid mites there are also parasitic ones. These are found mainly in birds and small rodents. The latter can infect a person with typhus if a bite occurs. But such a phenomenon occurs quite rarely in nature, so much so that little needs to be said about it.

But as for bird parasites, human bites by these bloodsuckers occur much more often. This is especially the case in domestic chicken coops, where the bird mite population can reach high limits. Due to its allergenicity, the saliva of such a bloodsucker, when bitten by a person, causes strong allergic-inflammatory reactions.

Differences between females and males

These parasites have a chitinous shell on their body, this is a shell that protects their body from damage. Males have such a shell covering the entire back, the body is brown. And in females the shell is much smaller and is only 1/3 of the body, they have a gray or reddish color.

Remembering such blood-sucking mosquitoes, quite often disputes arise as to who bites and who is more dangerous. Indeed, in the case of mosquitoes, only females attack. In this case, both males and females inflict bites, but it is the males who pose the greatest danger.

The fact is that when a female attacks a prey, she attaches herself for a long time until she is completely satiated. This period can last several days, which allows you to detect it on your body and take the necessary measures. In the case of males, everything is much more complicated. They deliver painless bites and get full very quickly. Having noticed a crawling parasite, few people will think that it has already bitten, much less infected with a dangerous disease. And if you consider that when infected with encephalitis, the disease progresses for a long time without any symptoms, then the person does not even suspect that he is infected with a serious disease.

Destruction of ticks indoors

Some species of ixodid ticks often live in livestock buildings in the south of the country. There are especially many ticks in poorly equipped barns and sheds (in cracks in walls, pillars, ceilings, floors, feeders, in loose material on the floor, under feeders and other places). A radical method of exterminating ticks indoors is to eliminate their habitats: acaricide dust is poured into cracks and crevices, followed by covering them with cement or lime with clay; rodent holes are filled with broken glass, stones, and covered with cement; Do not allow food residues and debris to accumulate under feeders and in the corners of the premises. After mechanical cleaning of the premises, the pillars, floor, and 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 liters per 10 m2 of area), as well as other acaricides (including in the form of aerosols).

Sometimes, in the fight against ixodids in livestock buildings, acaricide aerosols are used, obtained by burning bombs (NBK-G17) and using aerosol generators (AAG, AG-L6). The NBK-G17 checker (authors Nabokov, Burlyay and Kazakova) is cylindrical in 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 bomb is lit, after which it smokes heavily for 20 minutes. When the thermal mixture burns, the acaricidal agent sublimes, which upon contact with colder air condenses, forming smoke. Smoke has greater permeability, and therefore acaricidal effectiveness, compared to oil aerosols (fog). Before using aerosols, animals are removed from the premises and all holes in walls, doors and windows are covered with clay. The checkers are placed on sheets of iron or the ground (fire prevention measures) and lit, and the doors are closed.

The required concentration of aerosol (smoke) in a room can be created by burning a certain number of bombs (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, livestock are not driven into the premises).

What to do if bitten?

If alarming symptoms appear, you don’t have to wait, like a tick on a blade of grass, whether it will go away or not. You should immediately consult a doctor. With encephalitis (translated from Latin as “inflammation of the brain”), fever, headache, weakness, and nausea first appear. In some cases, the patient has impaired consciousness and paralysis. He might die. But doctors have cures for all forms of encephalitis.

The first symptoms of borreliosis are red rings around the bite. They can be gigantic - for example, on the entire back. A cough, runny nose, headache, and weakness, like a cold, also appear. But then the work of the heart is disrupted, bones and joints deteriorate, and red growths appear on the skin. The sick person may become disabled or die. The disease gets its name from Borrelia, a long, spiral-shaped bacteria that enters the bloodstream and begins to multiply there.

Another name is Lyme disease, because it was first studied in 1975 in the town of Lyme in the USA.

In the south of Russia, other ticks are also found, for example from the genus Hyalomma - they carry Crimean-Congo hemorrhagic fever (the patient’s temperature rises, a rash, spots and bruises appear on the skin, gums and injection sites bleed, the stomach may hurt, and jaundice is possible).

Ticks from the genus Dermacentor (found in southern Russia and Western Siberia) carry tick-borne encephalitis , Omsk hemorrhagic fever, tularemia, and tick-borne North Asian typhus (all of these are also dangerous diseases).

In any case, I repeat once again, it is important to see a doctor as soon as possible.

Tick ​​danger

The greatest danger is the bite of an arachnid. It is not only unpleasant and painful, but can also cause many diseases: brucellosis, tick-borne encephalitis, fever, intestinal infections, rabies, tetanus. When a person is bitten, the following symptoms develop after some time:

• hyperthermia up to +38 degrees;
• headache and dizziness;
• hyperemia at the site of the bite, irritation, slight swelling;
• muscle and joint pain, weakness, drowsiness, lack of appetite.

In advanced cases, Quincke's edema develops. The patient's breathing becomes difficult, the pulse quickens, and blood pressure may rise to critical levels. A rash of different shapes and sizes appears throughout the body, and itching is observed. The person's condition is serious, the risk of death is increased.

To provide first aid, it is necessary to urgently remove the blood sucker from the skin, always completely. It is strictly forbidden to crush the parasite. The most popular method is the use of sunflower oil. It is recommended to dip the affected area in oil or simply generously lubricate the lower part of the tick with it. The breathing holes are located in this part, so the parasite tries to quickly get out from under the skin. Another way would be to lubricate with kerosene or treat with hot wax. Such methods also make it possible to block the access of oxygen.

After extraction, it is recommended to save the tick so that specialists have the opportunity to determine in the laboratory the potential danger of its bite. If negative symptoms appear, it is recommended to immediately seek qualified help. Doctors recommend going to a medical facility in any case, even if no negative reactions are observed.

Special protective equipment recommended for purchase will help you avoid being bitten. They are especially relevant in the spring and summer, when many people go for a picnic in parks and forests. At home, the constant use of chemical repellents is unacceptable, so there are natural remedies that cope with this task: geranium, lavender, essential oils of eucalyptus, cloves, rosemary, mint.

Favorable conditions for reproduction

• For unhindered reproduction, parasites need favorable conditions. Moisture is very important, so the more precipitation, the more comfortable it is for them. Of course, food, so they settle closer to potential victims so that they can regularly get enough. And lastly, temperature, they cannot tolerate cold or heat, warm weather is optimal. On hot days, they hide in the thickets, where it is cool and humid.
• These conditions influence the fact that in some years their numbers drop significantly, when there is little rainfall and the weather is mostly hot and sunny. But there are years when populations increase significantly, and weather conditions contribute to this.
• It is also worth saying that natural conditions are the usual environment for these parasites. But unfortunately, they move from their usual environment to farms and pastures, and man himself is to blame for this. Because deforestation leads to mass migrations of insects. This situation is quite dangerous, especially for people and animals. After all, along with ticks come dangerous diseases, which means that there is a risk of epidemics.

Can a nymph carry encephalitis?

A tick of any species belonging to the ixodid family (the family of parasitiforms) is a carrier and distributor of all the viruses that it carries on its body. And the nymph, as is already known, has the same degree of possibility of infection as an adult tick. Accordingly, it can also infect a person with dangerous diseases through a bite.

The virus that causes the disease is transmitted from the tick nymph to humans through the saliva of the parasite and quickly spreads throughout the body through the circulatory system. If you are bitten, you need to act quickly and purposefully.

How many years do ticks live in unfavorable conditions?

To replenish energy reserves, the ability to develop, reproduce, lay eggs, and simply live, we need the blood of animals and birds. A person becomes a temporary host, promotes further development, but significantly reduces potential. Therefore, humans are a potential victim for ixodid ticks, but not the main one.

On a note!

A tick can live for years without food. When unfavorable conditions occur, it stops moving, metabolic processes slow down, and falls into suspended animation. It can remain in this state for about 8 years. At the sight of a victim, it instantly comes to life, crawls onto the body, feeds, and continues its normal life activities.

Without blood, the pest can live longer than without water. Environmental humidity plays an important role in the development of larvae, nymphs, and the vital activity of adults.

• Parasites wake up very early, when the air temperature barely rises above 0 degrees Celsius.
• They activate activity at +10 degrees Celsius.
• A favorable temperature for them is no higher than 22 degrees Celsius. Therefore, dry summers and heat within 30 degrees Celsius kill them.

What types of ticks are there?

Ticks of literally all families, except microscopic ones, are classified as arachnids. They, as befits this class, have four pairs of legs, and the body is divided into a head and an abdominal part.

The science that studies arachnids - arachnology - currently knows more than 30 thousand different species of mites living in all types of ecological environments - in soil, water, manure, rotting remains of trees. Most of them live separately, that is, they do not in any way affect the living conditions of other representatives of the animal world. Such individuals feed on plant food and its decaying remains, lay eggs in their habitat, from which larvae emerge, then adults, and the cycle repeats.

Other species have managed to adapt to a parasitic lifestyle, adapting to living conditions on the surface of the body or inside it in other, larger living creatures. Some parasites, in this case, feed on the waste products of their host, while others drink blood, which they need primarily to continue their kind.

So, today there are three large representatives of mites, which include each species or family of this type of arachnid.

Life cycle

• Everyone knows that with the arrival of spring and the first warmth, trips to nature can bring quite big problems, since ticks that have awakened after winter await us. This is true; during this period they are most active and therefore dangerous. Because the main goal is to satisfy hunger, and they are only busy looking for victims.
• After saturation and, of course, fertilization, females begin to lay eggs. Regarding the number of eggs that a female can lay during her entire life cycle, it can be from 100 to 17 thousand. Living in natural conditions, for laying they choose moist areas with loose soil. But it is quite possible that the apartment will become infected, in which case eggs can be found throughout the entire room.

• The entire life cycle includes four stages of development, the first is the egg, the second is the larva, the third is the nymph, and the fourth is the adult. Eggs can be of different shapes and have different shells, but they are always quite large in relation to the adult individual. Then larvae emerge from them; the period of development will always depend on temperature and humidity; the more favorable the conditions, the faster the development occurs. At this stage, they already have 6 legs, and the size of the body reaches 0.5 mm.
• Already at this stage it poses a danger to humans. In order for her to move to the next stage, she must be saturated with blood. Here the question arises, if this is the first bite of an individual, what danger does it pose to humans, and the answer is clear, great. The whole point is that encephalitis can be passed on to her from her mother, so to speak, by inheritance, which she successfully spreads through a bite.
• When she is satiated, the transition to a nymph takes place, here development occurs in three stages, the first is the protonymph, the second is the deutonymph, and the third is the tritonymph. Already at this stage, the parasite is quite dangerous, because it fed on blood, where infection could occur. The main differences from the imago are in size; the nymph does not exceed 1-1.5 mm, and it also has fewer bristles.
• There are types of parasites that skip the second stage of the nymph, and there are those that go through the first two. Regarding ixodids, the main condition that will allow the transition to adulthood is nutrition. In the absence of food, she will not die, but will simply go to winter and survive it just fine, hungry.
• Having received blood before or after wintering, the transformation into an adult begins. In this case, all changes relate to the structure of the body, new bristles appear, a shell, trachea, etc. are formed, this is an adult individual.

Types of parasites

In nature there are more than 40 thousand species of arachnids. Scientists divide them into 2 superorders: parasitiforms and acariforms. The former include ixodidae, argasaceae, gamasidae, nuttaliaceae, the latter include freshwater, armored, acaridia, feather, marine, scabies, thyroglyphoid, sarcoptiformes.

These are not all varieties, but the most popular. Each type has its own characteristics and differences:

1. Ixodid ticks are the most common. They are distinguished by a shell covered with hard plates, often reaching 2.5 cm in length, which is considered almost a record among all species. They live in places with a temperate climate, prefer to constantly be in foliage and grass, and become more active with the arrival of the first warm days after a long winter. The life cycle of ixodid ticks is no different from other individuals. Females are very fertile and can lay up to 17 thousand eggs per season. They parasitize humans or animals and can feed on the blood of the victim for up to 3 weeks.
2. Argas arachnids are characterized by a soft body, a small head that is almost invisible. They are of normal size and parasitize birds and animals. Sometimes they attack a person, the bite is painful, causing a rash and irritation.
3. The armored variety lives on trees and soil, is small in size, and has a solid body. It does not attack humans; it feeds on carrion, mushrooms, and plants. It poses a threat to domestic animals because it carries helminth eggs.
4. The gamasid mite lives in the burrows of rats and mice, parasitizes them, as well as poultry. It is small in size and lives up to 6 months. Produces toxic saliva that causes irritation when it comes into contact with the skin of birds and rodents.
5. The subcutaneous species poses a threat to humans and animals. It parasitizes under the skin for several years, consuming dead epidermal cells as food. It reproduces quickly; viable tick nymphs appear 2-3 days after laying eggs.

Such species are common and cause harm to animals, humans, and agriculture. They differ in that they are difficult to remove.

How to remove a tick?

Often, when a person sees a tick on himself, he instantly tears off its head: the person pulls the bloodsucker’s body, and the head remains under his skin. Neither the first nor the second are interested in such a development of events.

The easiest way is to take a cotton swab and apply oil to the skin around the bloodsucker. The oil will get into the tick's respiratory passages (and they are located not on the head, but behind the fourth pair of legs) - it will begin to choke and crawl out on its own. If there is no oil, you can use vodka, gasoline and even nail polish. The wound must be treated with iodine.

There is also a special tool for pulling out pliers - it looks like a small nail puller. Please note: no need to pull! You should carefully unscrew the tick from the skin.

You can also pull out a tick with a thread. A strong thread is tied into a knot as close as possible to the tick’s proboscis, then twisted in one direction, pulling it up a little until the tick unscrews.

Take care of those who are of the same blood with you - this is the law of the jungle.

Types of ticks

About 50,000 species of different ticks live on the planet. Moreover, this list is constantly updated, since etymology as a science does not stand still. Conventionally, ticks can be divided into two main categories. The first is parasitic ticks, those that feed on the blood of other creatures. The second is acariform mites - all other types of mites are also not always harmless. These include: dust mites, sea mites, hair mites, scabies and other types of mites.

The most prominent representative of parasitic ticks is the ixodid tick. It is he who causes the greatest concern among city dwellers who are planning to get out of the concrete jungle for the weekend into the bosom of Nature. Fear forces very suspicious people to give up going to the forest and even the park. Perhaps a closer acquaintance with this “monster” will help relieve excessive anxiety and understand that not a single tick in the world has the right to deprive a person of a breath of fresh air and necessary rest. So, who is the ixodid tick and how to fight it.

It is important to know

There are times when these parasites are most dangerous. For example, in April and May, forest and dog ticks are the most bloodthirsty; despite the name, they perfectly attack people, and this is where the danger of an encephalitis tick bite arises. Where you need to go with extreme caution is in parks, forests, and squares.

Much depends on weather conditions, as mentioned earlier, if the weather is unfavorable for them, then they are less active. But you always need to be as careful as possible, choose the right clothes when traveling outdoors and do not forget about specialized anti-tick products.

Nutrition of Ixodids

The diet of the ixodid tick consists of the blood and lymph of warm-blooded animals and/or humans. Parasites watch over victims on the surface of grass, bushes, and dead wood, crawling up to half a meter up from the ground. Clinging to a passing specimen, they crawl to an area with thin skin. Bristles and suction cups help them stay securely on the victim’s body. Having made a wound and stuck its proboscis into it, the parasite begins a meal, which can last up to 2 weeks.

The duration of the meal and the volume of blood absorbed depends on the gender and developmental phase of the tick.

• The larvae become saturated within 3-5 days, and their weight increases 20 times.
• Nymphs eat for 8 days, increasing their mass 100 times.
• Adult females remain on the body for 12 days, increasing their volume 120 times.

The gluttony of females is explained by the desire to provide future offspring with the greatest amount of nutrients.

Males in search!

It is interesting that the males, having quickly eaten, devote the rest of the time to searching for their other half for mating.

Arsenal of protection against ticks

The person himself does everything possible to be bitten. In spring and summer, he goes into the forest in shorts and a T-shirt, exposing his body to bloodsuckers. Moreover, people contribute to the growth of tick numbers: city parks are more comfortable for parasites to live than forest thickets.

It is quite simple for a person to protect himself from ticks: he needs clothing that covers the entire body. Anti-mite style consists of trousers tucked into socks, a jacket tucked into trousers, cuffs and a hood that fit tightly to the wrists. Having met a person in such armor, everyone who crawls towards him will give up hope.

And so that the tick generally looks for its hosts in another place, a person calls for help with repellents (from the Latin repellens - “repulsive”). They should be sprayed on the remaining exposed parts of the body. Such products contain diethyltoluamide - for ticks this substance is as terrible as its name is for a philologist (it is not recommended to treat small children with repellents, after all, they contain toxins).

A person without a twinge of conscience uses a more powerful weapon - acaricidal agents. If a tick crawls onto clothing sprayed with such a substance, its legs will be taken away and it will fall to the ground (there is no need to spray it on the skin: such products are even more toxic than repellents).

Plants also come to the aid of humans. The usual country fence does not protect against ticks, but a hedge of marigolds, lavender, and catnip creates a natural barrier: ticks do not like these plants. People treat their lawns and ornamental shrubs with chemical repellents (three days before the arrival of children; you cannot spray areas planned for garden beds).

In addition, a person has the opportunity to get vaccinated against tick-borne encephalitis (a month to a month and a half before ticks start hunting (the first bites occur in April).

As you can see, humans have enough opportunities to protect themselves from tick attacks and their consequences.

Destruction of ticks in nature

Ixodid ticks lay eggs on the ground, and some ticks choose wet places for laying, others dry ones, and others choose forest ones. If these conditions are violated, the tick eggs and the ticks themselves often die. To disrupt the living conditions 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 virgin lands, reclamation of wet pastures, weeds and weeds in autumn and spring, extermination of mouse-like rodents), and use chemicals methods, as well as natural enemies of ticks.

Isolation and change of grazing

are 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 prevent domestic animals from entering the tick-infested area of ​​the pasture for a period during which the ticks die of starvation (Boophilus calcaratus after 6-7 months, Rhipicephalus bursa after ten months). If you graze livestock on each plot for 25 days (the development of the Boophilus calcaratus tick from a larva to a suckling female takes 21-24 days) and return to the previously used plot 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 an important role in the fight against ticks Boophilus calcaratus and Rhipicephalus bursa. It is necessary to move cattle in the spring to subalpine pastures before ticks become active (cattle in early April, and sheep no later than mid-May). Against most ixodid ticks, changing pastures is ineffective, since these ticks are capable of fasting for a longer period of time (more than one year) and can feed not only on domestic animals, but also on wild animals.

Agricultural activities

carried out in tick habitats.
This creates unfavorable conditions for the life of ticks in pastures and other places, as a result of which the number of ticks and other parasitic arachnids in nature decreases. Depending on natural conditions and the species composition of ticks, certain measures predominate in the complex of agricultural measures. Reclamation (drainage)
of swampy and low-lying pastures leads to changes in the habitats of moisture-loving ticks in an unfavorable direction for them, resulting in their mass death.
In autumn and spring, burning
tall, dry grass, weeds and weeds, which serve as a refuge for ticks and their hosts - small wild animals, in certain areas of pastures in autumn and spring, helps to sharply reduce the incidence of ticks in these places.
Deep plowing, disking and harrowing of
pastures, destruction of hummocks and bushes, sowing of annual and perennial grasses on natural pastures are important links in the fight against ticks.

Chemical methods

Tick ​​control in natural conditions is sometimes carried out by spraying acaricide dusts using helicopters and airplanes and, in limited areas, using special pollinators.

Natural enemies of ticks.

The insect worthy of attention is Hunterellus hookeri, the female of which lays up to 20 eggs in the body of ixodid tick nymphs. The larvae hatching from the eggs of the parasite 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; Dangerous for them are mold fungi, the hyphae of which permeate the body of ticks.

How long can ticks live on the host's body?

How long ticks live on the body of an animal or person depends on how quickly they suck blood. The life phase has several stages:

• first the parasite attacks a victim from grass, bush or tree;
• then selects the place where the skin is thinnest;
• attaches, injects a substance that numbs the bite site and begins to feed on blood;
• detaches for reproduction.

The ixodid species needs nutrition once during the active phase of its life cycle, so they live on the body for up to two weeks. Females drink blood longer than males. People usually discover ticks before the parasite has a chance to lay offspring. But don't worry, larvae cannot develop on human skin due to its thickness.

The Argasid type of tick often bites people at night; it does not stay on the body for more than two hours. The larvae can remain for about five days and then begin to molt.

There are scabies mites that live on the human body and provoke the development of scabies. They are contagious and can be transmitted through personal items, as well as from animals. This mite (itch) does not live long on humans, and the number of parasites depends on the immunity of people. Scabies mites cannot live outside the host’s body, on clothing or in the external environment; they die quickly enough.

The encephalitis tick can be of any type; it is called so because it carries the causative agent of encephalitis - a very dangerous disease. A tick bite is the most common way of contracting the disease. A complication of encephalitis is death after meningitis as a complication. If an infected tick has already bitten someone, then it will no longer live; the main thing is to remove it correctly so that the proboscis and head are not left in the wound.

The ear mite, which mainly affects animals, is rarely found on the human body and lives no more than two months. It gets into people's homes on clothes, shoes, vegetables and fruits.

Other types

There are other types of parasites. The scabies mite is a common one. Causes scabies in humans and animals. Life expectancy is no more than 6 weeks. During this period, the female can lay many eggs, which turn into nymphs quite quickly.

Ear mites do not pose a threat to humans. It mainly harms animals. It lives in the auricle, feeds on its secretions, causing severe itching, irritation and inflammation.

Scratch infections often occur. The dust species often lives in blankets and pillows. It does not parasitize humans; it feeds on dead skin cells, accumulations of dust and fluff. Life expectancy is 4 months. During a season, a female can lay more than 35 thousand eggs. It often provokes the development of asthma in a person.

Spider mites are safe for animals and humans; they are herbivores and feed on plant juices. The only danger of this species is the spread of gray rot, which is destructive to plants. The marine species does not threaten animals or humans; it parasitizes marine life. Lives in salt and fresh water, in stagnant bodies of water. The predatory tick poses a danger to any other species, since it feeds on its relatives. Sometimes such individuals are specially introduced into greenhouses to destroy the harmful spider species.

The granary or flour species does not pose a threat to humans, unlike the blood-sucking species. It is considered a serious pest; it can destroy grain reserves, contaminating them with waste products. The pasture parasite is dangerous to humans and animals. Lives in forests, sometimes in the steppe, near populated areas. Carries serious diseases, for example, plague, fever, encephalitis, brucellosis. Animals are also threatened by dog ​​ticks, which live everywhere and cause serious discomfort.

Where do forest ticks come from?

Ticks have always inhabited forests, meadows, plains, mountain slopes, etc. However, previously they were not paid much attention. Many years ago, people suffered from encephalitis, borreliosis and other dangerous viruses after tick bites, but these were rather isolated cases. The issue of interconnection was not addressed at that time. At the beginning of the last century, homestead farming began to actively develop, which resulted in a strong wave of migration of forest ticks to cities and suburbs; the parasite can enter an apartment on the body of domestic animals.

Now ticks can be found both outside the city (in the forest or, for example, near a lake) and within the city: parks, squares, shady alleys are the favorite habitats of parasites.

Mite feeding styles

Ticks are usually divided according to the type of feeding into single-host and multi-host. The feeding habits of a tick are determined by its species; it cannot change at its own discretion and choose a different pattern.

Single-ownernew

Such individuals prefer to live on the body of one owner. These parasites constantly live on the body of a warm-blooded creature, where they mate and lay eggs. These types include scabies and subcutaneous mites. In rare cases, if an insect experiences severe hunger and cannot find a biologically suitable individual, it may go in search of another owner.

Single-host scabies mite.

Multi-owner

This group includes parasites that choose any warm-blooded creatures as victims. In the early stages of development, parasites most often choose small rodents, and later they look for a larger host. Also called multi-host ticks are ticks that do not specifically look for a source of food, but attack any animal that is in an area accessible to it.

Ticks on warm-blooded animals.

Can ticks jump and fly?

None of the tick species can fly, so there is no need to fear an attack from the air. Can ticks jump from tree branches and bushes? No, they are not capable of jumping. Their main way of attacking a victim is to cling to it.

Ticks do not prefer to climb to a height above one and a half meters, but this is quite enough for them. In the event of a threat, such as a fire, the ticks simply detach from a branch or blade of grass and simply fall down. Some might call it a jump, but it's just an uncontrolled fall down.

What to do?

So, what to do if a nymph is bitten by a tick? This happens very rarely, due to the fact that this stage of tick development does not allow it to rise above the grass. If you suddenly find that the nymph has already attached itself, then first of all coat its body with vegetable oil. The respiratory tract of ticks is located on the abdomen, the oil will close these openings, and the nymph will have to look for a way out in just a few minutes. Carefully pry it up with tweezers and remove.

If an adult has attached itself, then also try to manipulate the oil. Melted paraffin from a candle helps a lot: fill the insect's abdomen with hot paraffin and wait a few minutes.

Another method of getting rid of an attached imago is to lubricate it with kerosene. This will cause him to move and loosen his bite grip. Carefully grasping the tick with tweezers and making light rotational movements in different directions, we remove the parasite. In any case, be sure to go to the medical center, taking with you the body of the nymph and the tick for testing in the laboratory for the presence of dangerous viruses. It is recommended to treat the bite site with iodine for several days in a row - 3-5 times a day.

Choosing a bite site

Ticks never immediately attach themselves to a new host, but patiently search for a suitable place. Properly selected clothing for walks in nature will protect against tick bites

When walking through the forest, periodically inspect yourself and your loved ones for ticks. This simple action will protect you from an unpleasant bite, and possibly more serious consequences.

When choosing a bite site, ticks are guided by many factors. Since human skin is heterogeneous and different areas differ in temperature, degree of humidity, saturation with blood vessels, softness or roughness, acid-base balance, the tick faces a difficult task - to find exactly the place that is best suited for effective feeding.

But if for some reason it was not possible to get there, they also do not disdain lower-quality areas, such as the chest, stomach, buttocks or even legs.

• on the ears of an animal,
• on the head
• on the paws between the toes,
• in the groin area,
• near the anal area.

That is, in those places where the tick is least likely to be harmed during the animal’s self-cleaning.

Ticks in an animal's ear are a common occurrence after a walk.

How to remove a tick from your body

If, despite all your precautions, a tick still bites you, do not rush and do not immediately try to pull it out with your fingers. With hasty actions, you will only achieve that you tear off the body of the parasite, leaving its entire mouthparts in the depths of your skin. Practice shows that the only competent way to remove a tick from the body is to unscrew it. All other methods do not work! Under no circumstances will the tick come out on its own. Therefore, smearing it with oil, cream, Vietnamese balm and other drugs is not only useless, but also dangerous. An irritated mite will burrow even deeper into your body, releasing even more of its saliva and other enzymes, which will further infect your epidermis. Therefore, arm yourself with ordinary sewing thread and patience. Tie a thread to the body of the tick at the very point where it penetrates the skin. Hold both long ends of the thread between your index finger and thumb and gently twist them clockwise. Two or three turns - and the tick will unscrew from the wound like a self-tapping screw from its socket. Without removing the tick from the thread, carefully examine it and make sure that all its body parts are in place. Disinfect the wound with any antiseptic that is in your home medicine cabinet - hydrogen peroxide, iodine or regular alcohol.

If you belong to the category of suspicious people who are capable of dying from fear of the disease earlier than from the disease itself, then put the tick in a jar and take it for analysis to the nearest laboratory for your own peace of mind. After waiting for the result and making sure of your own safety, congratulate yourself on a new life experience that you can share with your loved ones and friends, teaching them how to unscrew ticks with a thread. By the way, special devices for twisting pliers have appeared in pharmacies - you can inquire about their availability and get a convenient tool for the future.

Nutrition of larvae

Where can tick clutches be located?

• Most often - in nature, on soil or on plants.
• Less often – on the host’s body. In this case, the larvae will also feed on his blood.

The hatched larvae begin to look for a victim, and often there are several of these young ticks per host. Feeding takes approximately 3-4 days, after which the larvae leave the host, once again entering the natural environment. Here they molt, turning into nymphs, then again find a host - their feeding will continue for about 7 days, after which the nymphs again leave their prey, turning into an imago (adult) or leaving for the winter.

This is the process of tick reproduction.

The figure schematically shows the stages of a tick bite

However, it must be said that the pliers are able to regulate the depth of immersion. While conducting research, scientists noticed that some types of ticks do not penetrate the victim’s tissues the entire length of the mouthparts, but only partially, and stop when they reach the branching of blood vessels. It was noted that this feature is inherent in species that often change hosts, and is a kind of protection of the chelicerae from possible mechanical damage when the skin is thick. Indeed, in the event of an injury, the likelihood of the next meal will be in question.

Video: close-up of a tick bite

What argas mites look like: appearance (with photo)

Argasid mites (argasids) are external parasites, as well as carriers of some pathogens of infectious and protozoal diseases. They are most often found in the southern regions. Some species of argasids can live in poultry houses and livestock buildings, where they briefly parasitize animals, feeding on their blood at night.

When describing this variety of ticks, it is worth noting that, unlike ixodids, argasid parasites lack dorsal and ventral scutes. The proboscis of imagoes and nymphs is on the ventral surface, so it is not visible from above. The general characteristics of argasid mites are their particularly large size and the presence of a flattened soft body. The proboscis of these parasites is similar in appearance to the proboscis of ixodid ticks.

Nymphs, like adults, have four pairs of limbs, but they lack a genital opening. The round larva has three pairs of limbs. Her proboscis is located in the front of her body.

The body structure of the Persian tick is similar in appearance to a bug. It has a flat, grayish-yellow, ovoid body with a visible edging around it. The length of the tick is 10 mm and the width is 6 mm. The insect has two pairs of legs pointing forward and two pairs pointing back. Ticks go through all stages of development: eggs, larvae, three nymphs and adults. The female parasite is capable of laying from 30 to 100 eggs, from which larvae appear after 2-3 weeks, parasitizing mainly poultry. Each tick in the nymph stage before molting feeds once on the blood of an animal for 1-2 hours, and in the adult stage - several times. It takes 3 to 8 months for the development of one generation of the Persian tick. All stages of the parasite can overwinter. The Persian tick is mainly a carrier of the causative agent of spirochetosis.

The cat tick is distinguished by a thickened body of a grayish color, which is narrowed at the anterior end. Body length can reach 15 mm. The parasite has claws on its feet. The sheep tick parasitizes sheep and other domestic animals.

This parasite goes through all stages of development: eggs, larvae, three nymphs and adults. Female ticks lay eggs in cracks in the walls of barnyards. The entire process can take from 7 to 30 days. During this time, one female is capable of laying from 50 to 500 eggs. After about 30-45 days, larvae emerge from the eggs, which attack animals in the fall. Larvae and nymphs of the cat tick can parasitize animals for up to 45 days. Having had their fill of blood, the nymphs go into hiding, where they turn into adults. Adult ticks repeatedly suck the animal's blood for 10-40 minutes. The main characteristic of cat ticks is winter blood sucking.

In summer, females lay eggs in crevices and cracks in rooms where animals are kept.

Infection with the sheep tick can lead to paralysis (sometimes death) of sheep. In addition, these ticks can be carriers of some sheep hemosporidia. Ticks are carriers and carriers of the pathogens of equine infectious encephalomyelitis, brucellosis and tularemia.

Look what argas mites look like in these photos:

Lifespan of a tick after a bite

How long a tick lives after a bite depends on its stage of development and the amount of blood it sucked. If the individual is young, then after the bite the chitinous cover begins to change and feeding will be required only before the next molt (2–7 days).

On average, arachnids live 2–3 years, which is exactly how long it takes to reach sexual maturity, then the parasites mate, lay eggs and die. The lifespan of ticks largely depends on the availability of food. Without food, insects hibernate, which prolongs their life cycle.

Argas ticks at the larval stage also molt after a bite, but before reaching maturity, for almost a year, they can make several bites, and then their life span lasts up to 7–8 years.

As soon as the drunk blood is digested, the tick will again be waiting for a potential victim. Thanks to slow metabolic processes and a sedentary lifestyle, arthropods have enviable vitality.

Large varieties

These are the representatives whom we are accustomed to seeing in the world around us and are accustomed to fear. In the central zone of our country, there are predominantly ixodid types, which are carriers of many serious diseases of viral and bacterial etiology, both for humans and domestic animals. Here is a far from complete list of diseases that these small arachnids can infect:

• tick-borne encephalitis,
• rickettsioses,
• Lyme disease,
• borreliosis,
• canine piroplasmosis,
• bartenellosis.

Without proper treatment, most of these diseases have a poor prognosis.

Infection occurs at the moment of the bite, when the parasite digs into the skin and begins to suck blood, which it does not need for nutrition, but so that the fertilization process is much more efficient, so only females bite. The causative agents of the disease are found in the saliva of the tick, with which they penetrate the wound and begin their development.

Generations of generations

Depending on the species and environmental conditions in which ticks are forced to live, the number of generations per year can vary greatly. In some species, the cyclicity of breeding seasons is confined to the seasons of the year or external environmental conditions.

There are species that develop from egg to death within a year. Others can produce up to 20 generations per season. Ixodid ticks are long-lived. These arthropods do not have time to fully develop in 1 season. Their lifespan ranges from 2 to 4 years depending on environmental conditions and hunting luck.

Source

Ixodid ticks

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

Morphology of mites.

Ixodids are relatively large ticks. Their sizes range from 2 mm (hungry) to 20 mm (fed females). The body is not divided into a cephalothorax and abdomen. It is covered on the outside with chitin of unequal thickness. On the dorsal and ventral sides, a thickened layer of chitin forms scutes: dorsal in males and females and ventral only in males. By the size of the dorsal shield it is easy to distinguish males from females: in males it covers the entire upper surface, and in females, as well as in larvae and nymphs, only the anterior part of the body. In the front part of the body are the oral organs, which form the proboscis, consisting of chelicerae (upper jaws), hypostome (lower jaw), a pair of palps (tentacles) and the base of the proboscis. With the help of chelicerae, the tick cuts the animal's skin before sucking blood; the hypostome, armed with teeth directed backwards, is an organ of fixation; The palps serve as an organ of touch. Ticks of different genera may have a long or short proboscis with a quadrangular or hexagonal base. The legs are connected to the tick's body through coxae, which on the anterior pair can be split, weakly split, or unsplit. On the ventral side at the level of the second pair of legs there is a genital opening and behind the fourth pair of limbs there is an anus. In males of most ixodid genera, ventral scutes are located near the anus: adanal - lateral to the anus, accessory - outside the first; some ticks may have subacal scutes located under the adanal scutes. Most mites have an anal groove located behind the anus, while some representatives have an anal groove located in front or absent. On the dorsal side, at the level of the second pair of limbs, some ticks have eyes, and at the back of the body there are depressions called festoons. The spiracles (stigmas) are located on the side of the body, behind the fourth pair of legs and are surrounded by a plate (peritreme) (Fig. 62). In ixodid ticks, the intestines have numerous blind outgrowths that fill with blood during the period of parasitism on animals.

The family Ixodidae includes six genera: Ixodes, Hyalomma, Dermacentor, Haemaphysalis, Rhipicephalus, Boophilus. Over 50 species of ixodids live on the territory of the Soviet Union, most of which are recorded in the southern part of the country.

Biology of ixodid ticks.

Typically, on the body of animals, male ixodids fertilize females, which, after sucking blood, fall off, crawl into shelters and, depending on environmental conditions and the degree of saturation with blood, lay from 4 thousand to 15 thousand eggs in 10-20 days, after which they die. Tick ​​eggs are relatively large (about 0.5 mm in length), oval in shape, yellow-brown in color, covered with a hard shell, and immature. The eggs mature within a few weeks (up to a month or more). Through the resulting crack in the egg shell, a larva about 1 mm long hatches, has three pairs of legs and lacks 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 animal’s body. Thus, to fully develop from the egg to the 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, by adults - 8-10 days. Most ticks overwinter in the external environment at various stages of development. Depending on the type of development and feeding method, ixodids are divided into single-host, two-host and three-host.

Single-host mites

all three active stages of metamorphosis take place in one animal, and only the imago leaves it to lay eggs in the external environment (Boophilus calcaratus, Hyalomma scupense).

Two-host ticks

in the larval and nymph stages they live on one host and in the imaginal stage on another (Rhipicephalus bursa, Hyalomma plumbeum, Hyalomma detritum).

Three-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.).

The larvae and nymphs of two-host and three-host ticks prefer to attack mouse-like rodents, birds, and less often reptiles, while adult ticks, as well as the 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. There are no eyes. Cokes I are not split. Anal groove in front. In males, the entire ventral surface is covered with scutes (Fig. 63). The dorsal shield, 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 and are moisture-loving.

Ixodes ricinus is one of the most common ixodid ticks. It is found in greatest quantities in the northwestern and central regions of the USSR, and is almost absent in the steppe and semi-desert zones. During the year, 1 generation develops. Ticks can go hungry for more than two years. Adults 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 the Leningrad region. The adult attacks animals in the spring and summer (no later than July). This tick carries Babesia bovis and Francaiella caucasica.

Genus Hyalomma (glasseye).

Of the ixodids, these ticks are the largest (up to 2.5 cm), have a dark body color, a long proboscis with a quadrangular base and clearly visible eyes. Coxae I are split, the anal groove is posterior and there are three pairs of central scutes in males (Fig. 64). They are warm-dry-loving mites, therefore they are widespread in the steppe, semi-desert and desert zones. The species Hyalomma scupense are classified as single-host ticks, Hyalomma detritum and Hyalomma plumbeum are classified as two-host ticks, and Hyalomma anatolicum and Hyalomma asiaticum are classified as three-host ticks. Some species (Hyalomma scupense, Hyalomma detritum and Hyalomma anatolicum) often live in barnyards. Most ticks attack animals from spring to autumn (maximum in June), with the exception of Hyalomma scupense, which parasitize domestic animals during the cold season (from autumn to spring).

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

Genus Dermacentor (leather cutter).

Ticks of this genus are characterized by a spotted pattern with a silvery tint on the dorsal shield in males and females, so they can be easily distinguished macroscopically from other iscodids. Dermacentor mites have a short proboscis with a quadrangular base, eyes, an anal groove located posterior to the anus, and split coxae I (Fig. 65). They are widespread in different zones of the country, develop according to the three-host type: larvae parasitize mainly on mouse-like rodents, nymphs - on larger wild animals (hedgehogs, hares) and birds, adults - on domestic and some large wild animals (wolves, etc. ).

Mature ticks more often attack animals in spring and autumn. They are capable of fasting for a long time (up to three years). The species Dermacentor marginatus, Dermacentor nuttalli, Dermacentor silvarum, Dermacentor pictus, Dermacentor daghestanicus are of veterinary importance as ectoparasites and carriers of causative agents of piroplasmosis and nuttalliosis in horses, piroplasmosis in dogs, as well as theileriosis and anaplasmosis in sheep.

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. The three-host ticks Haemaphysalis otophila and Haemaphysalis puncata are of veterinary importance; they transmit Piroplasma bigeminum, Piroplasma ovis and Theileria annulata.

Genus Rhipicephalus (fanheads)

. Heat-loving, relatively small mites are red-brown in color, 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 the foothills and steppe regions). Animals are attacked in the spring-summer period of the year. Within a year, the development of one generation of mites 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).

Genus Boophilus (bull lover).

Only one species, Boophilus calcaratus, has been recorded on the territory of the Soviet Union. This is a heat-moisture-loving mite and develops according to the single-host type. It has a short proboscis with a hexagonal base, eyes, weakly split coxae I and two pairs of ventral scutes in males. Females have a light brown cuticle and a tongue-shaped dorsal shield. This tick often attacks cattle, less often horses, and very rarely sheep. It does not parasitize small wild animals. It is often found in Crimea, the Caucasus, and Central Asia. The development of one generation lasts about two months (on an animal 20-24 days and on land 30-45 days). During the warm season of the year, 2-3 generations of ticks develop. The larva is capable of starving for up to seven months (Fig. 67). It is a carrier of the causative agents of piroplasmosis, southern francaiellosis and anaplasmosis in cattle.

What do they eat?

The nutrition of ticks depends on the types of parasites:

• Saprophages prefer to eat organic food. Organisms are beneficial and take part in the formation of humus. Some parasites spoil supplies, grains, flour;
• Dust and scabies mites consume exfoliated particles of human epidermis;
• Subcutaneous eat fatty deposits that are found in human hair follicles;
• Predators parasitize animals, humans, and plants. Blood-sucking species consume only blood. There are varieties that attack herbivorous mites and thrips.

Ticks are dangerous insects that pose a threat to human life.

Since a bite can cause serious diseases that may not always be treatable, it is imperative to study their main characteristics - structural features, species, habitats, and other important facts.

They can wait absolutely everywhere - on the street, in the forest and even at home. It’s better to prepare in advance and protect yourself from them, so you can protect yourself and your loved ones from unpleasant consequences.

Habitats

To protect yourself from insect bites and attacks, you should consider where ticks live. The majority of parasites prefer to live in damp forests, grassy meadows, and bushes.

But there are individuals that parasitize in residential areas near people. They are called saprophytes or dust mites; they feed on house dust and dead skin cells of the epidermis.

Some species can live under the skin, in hair follicles.

Ixodid ticks like to live in places with high humidity (up to 80%).

Suitable areas for their habitat are:

• Slopes warmed by the sun, on which there are dense thickets of grass and shrubs;
• Forest edges and adjacent glades;
• Places in the shade of trees that are covered with thickets of ferns;
• Banks of rivers, lakes, streams.

Mass reproduction and spread of ticks

Despite the fact that dog and taiga ticks are quite common in our territory, they can not be found everywhere. They live in deciduous and coniferous forests with lush herbaceous and shrub vegetation. Moreover, the hotter the region, the more humid areas ticks prefer, and vice versa.

Typical habitats for ticks are damp forest edges well illuminated by the sun, paths and lawns in parks, and vegetation near water bodies. If a tick finds conditions favorable for its residence, it begins to actively reproduce.

Active population outbreaks have been described for ticks, when a large number of adult individuals and their larvae are concentrated in a small, favorable area. There is no need to explain that when a person enters such biotopes, contact with ticks is almost inevitable.

Foci of mass reproduction of ticks in the north of Russia also appear on the borders of different natural stations (rough terrain); during deforestation, parasites move to pastures, where they actively feed on farm animals. In nature, the reproduction of ticks is restrained by the low density of victims, but on pastures there are more than enough hosts.

The phenomenon of mass reproduction is also dangerous because when the population reaches a certain density, a massive spread of parasites occurs to neighboring territories, where population outbreaks also occur over time. If such a population includes ticks that are carriers of a disease, for example encephalitis, then the disease migrates along with its “hosts” further and further. This can lead to high morbidity among people and even an epidemic.

It is possible to identify places with a significant probability of such an outbreak, but it is extremely difficult to predict it, because the reproduction of ticks is influenced by many factors (see below), including weather conditions, which vary greatly from year to year.

Why are tick larvae and nymphs dangerous?

The size of hatched tick larvae is 1 mm. These creatures are inactive, it is not easy for them to find the first victim. As soon as they are born, they begin to look for food in the first hours. This makes them dangerous for animals in the forest.

Diagnostics

Identifying the causative agent of borreliosis in the body is not easy. Borrelia may be present in affected tissue (for example, at the edges of the erythema) or fluids, but they are very difficult to detect there. The most accurate and reliable method is serological testing for the presence of antibodies.

In the DILA portfolio, tests for Borreliosis, Borrelia, IgM antibodies and Borreliosis, Borrelia, IgG antibodies are available to identify antibodies. Class M antibodies (IgM) are the first to be produced (1-3 days after infection), so they are optimal for diagnosing recent infection. G family globulins (IgG) can only be detected several weeks after infection, making them a late diagnostic marker. If the test for antibodies gives questionable or positive results, it is recommended to undergo Borreliosis, IgM/IgG screening (immunoblot for doubtful/positive). To study the extracted tick, it is proposed to test the tick for borreliosis, Borrelia burgdorferi, PCR - quality, which is aimed at detecting DNA fragments of the causative agent of Lyme disease.