Ixodid ticks (Ixodidae) are one of the most famous families of the subclass Ticks (Acari). They are found on all continents and live within almost all distinguished natural and climatic zones. Ixodids live even outside the Arctic Circle, which indicates their high adaptability and ability to survive in extreme conditions.
The greatest species diversity of ticks is characteristic, first of all, of the forests of the tropics and subtropics (due to the relatively high level of humidity, the complex longline composition of vegetation, and the abundance of possible hosts).
However, areas with a temperate climate are also characterized by a rich species composition of these parasites, and Russia is no exception. Hundreds of species of blood-sucking parasitic mites live within our country: they are found everywhere - from the taiga to arid semi-deserts. Bloodsuckers have perfectly mastered all possible ecological niches and play a significant role in anthropogenic cenoses.
Moreover, ixodid ticks are common inhabitants not only of natural plant associations in nature, but also of parks, squares, lawns and flower beds in cities. Such a neighborhood is dangerous for humans, since these parasites are carriers of a number of pathogens of severe natural focal diseases, such as tick-borne encephalitis, borreliosis (Lyme disease), typhus, etc.
We will talk further about exactly where and in what months of the year the risk of meeting ticks is greatest ...
Where are ixodid ticks found?
Ticks concentrate where there are the necessary microclimatic indicators and where their potential hosts live. Within the main natural zones, these bloodsuckers are distributed in a mosaic pattern, and can often form massive concentrations of numbers.
At the same time, it should be borne in mind that ticks migrate insignificantly in the horizontal direction - they take a wait-and-see attitude, and resort to active pursuit only in exceptional cases.
Actually, the entire movement of these parasites is associated with the search for a future host, therefore, the spatial distribution of parasites fully corresponds to the places of movement, life and shelters of small and large mammals, birds and reptiles.
Below in the photo, ticks are clearly visible in a bird around the eyes:
And here - the parasite stuck to the head of a rodent:
Thus, the main habitats of ticks are:
- forest trails;
- well-heated and moist forest edges and forest clearings;
- pastures;
- parks and squares in cities, lawns;
- kitchen gardens, gardens in the country, which are often visited by pets and people.
The microclimate in a particular location has a key influence on the life and activity of ticks - for them it is a decisive factor in the passage of ontogenesis, most of which they live as free-living organisms. Even if the tick lived in suitable conditions before feeding, having fallen off after bloodsucking from the host in a position unfavorable for him, the parasite dies.
Therefore, this group of species has developed special adaptations to counteract the harmful effects of the environment.These resistances are expressed in the choice of habitats, and here two groups of ticks are distinguished:
- pasture bloodsuckers;
- burrow bloodsuckers.
Pasture and burrow bloodsuckers
In search of better microclimatic conditions, some species of ticks took a simplified path and settled in the burrows of their hosts, where it is always warm enough, humid and there is food. Other species have adapted to life in forests and open spaces.
The most striking example of a pasture parasite is the dog tick (Ixodes ricinus) - one of the most common in Russia and in the Moscow region, in particular. It lives, first of all, in fairly humid types of forests (mixed and deciduous), preferring to be in dry leaf litter, as well as among succulent vegetation.
On a note
The name "canine" does not mean that the parasite feeds only on dogs - almost any mammals, as well as birds, frogs and lizards, can become its victims.
In heavily waterlogged places, in swampy areas and peat bogs, the dog tick is not found. Likewise, these parasites avoid dry, pure coniferous forests. That is, the decisive factor in this case is humidity.
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With a lack of water in the body, ticks descend on wet substrates and absorb moisture throughout the body.
It is a common misconception that ticks fall from trees and shrubs. In reality, they do not climb trees, but are exclusively in the grassy layer. Therefore, it is juicy, tall grass in places of frequent movement of animals and people that poses the greatest danger.
As for burrow mites, they live almost exclusively in the burrows and nests of their owners, and for this reason they usually do not pose a danger to humans. These include, first of all, Argas ticks, less often similar species are also found among Ixodes.
A vivid example of burrow parasitism among ixodid is the parasite of the shore swallow, which lives in the nests of these birds. The bloodsucker is a highly specialized species, and feeds exclusively on the blood of the swallow. Accordingly, the maximum correlation is observed in the life cycles of the parasite and the host: the adult stage of the bird corresponds to the adult tick, and the timing of hatching corresponds to the appearance of larvae and nymphs.
Thus, it is pasture free-living ticks, which are carriers of many infections, that pose the greatest danger to humans and domestic animals.
Life cycle of parasites
The life cycles of ticks are quite complex, which is associated with the peculiarities of metamorphosis and the need to search for and change hosts. At the same time, the vital activity of the same species differs significantly within different natural zones, and directly depends on the microclimatic indicators of habitats. The rhythms of life cycles are entirely dependent on the seasonal dynamics of abiotic factors, such as daylight hours, humidity, temperature, etc.
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The most primitive are continuous cycles, in which synchronization with seasonal rhythms is minimized. This type of ontogenesis is characteristic of species living in a warm and humid tropical climate or in the burrows of animals and birds, where fluctuations in microclimatic parameters are insignificant.
The most complex cycles are characteristic of ticks, which need special adaptations to survive adverse environmental conditions (primarily winter temperatures).
The longest and most complex cycles of development are characteristic of the European taiga and forest tick, whose ranges have shifted far to the north, much further than the ranges of other species. Normally, for the full development of each stage of ontogenesis, it takes about 1 year, so the minimum period of development from an egg to an adult is 3 years, and the maximum is 6 years.
Imagoes, mostly adult and hungry females, attack large mammals and humans in April-May, and the peak of aggressiveness occurs precisely in the second decade of May. At this time, they are waiting for their prey in tall grass in pastures, near ponds, forest paths, in parks and squares in cities.
If the female manages to successfully suckle, then feeding begins, which lasts for several days., after which the tick disappears, and after about 2-3 weeks it starts laying eggs. Parasites lay eggs in approximately the same places where separation from the host occurred. For these bloodsuckers, in general, the creation of any nest structures or care for offspring is not typical.
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Often, the eggs are attached to grassy vegetation, less often the female lays them directly on the fur of animals - then the hatched larvae will not need to look for a host.
The eggs laid in summer hatch into larvae that feed on small rodents and birds. They are tiny and have only 3 pairs of limbs, so they are sometimes confused with insects.
The photo below shows the larvae of the tick:
After feeding, the larvae look for a place for wintering: they mainly choose leaf litter and depressions in the bark of trees. There, in a state of diapause, small bloodsuckers wait out the winter. If the larva does not have time to feed before the onset of cold weather, it dies.
Sometimes the larvae have time to molt into nymphs before winter, but often molting also occurs only after leaving diapause. Each molt is accompanied by bloodsucking.
Tick nymphs differ from larvae in their larger size and the presence of another (fourth) pair of legs. They are able to feed on larger animals such as dogs, cats, foxes, hares.
In the spring and summer-autumn period of the 3rd year from the beginning of the life cycle, adult individuals appear. They begin to feed immediately, or again go into diapause. Feeding is necessary for the female primarily for the maturation of eggs, so it is imperative that mating occurs before feeding. Males either do not feed at all, or feed for a very short time, since they perform only the function of inseminators.
Thus, the entire life cycle of ticks is associated with the search for a host and nutrition. The success of the parasite's hunting directly depends on the choice of a suitable place for attachment to the host's body.
Tick bites and their danger to humans
The most common and massive in Russia and the CIS countries, common forest (dog) and taiga ticks carry a number of pathogens of extremely dangerous human diseases, such as:
- different forms of tick-borne encephalitis;
- tick-borne typhus;
- Lyme disease (borreliosis);
- tularemia and some others.
You can pick up a tick in a variety of places - from a walk in the forest to a city park. The parasite penetrates under clothing and sticks to the body, mainly in areas with thin, well-perfused skin. (The favorite places for suction are the neck, chest, places behind the ears and the ears themselves, the head, axillary and inguinal regions).
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Also, ticks can be brought into the house on clothes or shoes, on pet hair, with bouquets of wildflowers. Already in the house, the parasite can bite any of the family members, even after a considerable period of time.
The tick infects its host already during suction, when it injects saliva containing pathogens of a particular infection under the skin. Moreover, the longer the tick is on the body, the more likely it is to get sick.
Symptoms of the disease do not appear immediately: the incubation period can last up to one month. In the case of tick-borne encephalitis, the development of the disease can proceed in different ways, but there are also common symptoms: a sharp increase in temperature, muscle and headaches often occur. In the case of tick-borne borreliosis, a characteristic sign of infection is the appearance of the so-called migrating annular erythema - on the skin near the wound left after a tick bite, concentric rings of reddish, brown or yellow color are formed (an example is shown in the photo below).
Prevention measures: how to protect yourself from the negative consequences of contact with ticks
The best protection against ticks is the prevention of their possible bites. It should be borne in mind that the tick bite is almost impossible to feel (the saliva of the parasite contains anesthetic substances). Also, not every person is able to feel how the tick moves through the body.
Since these parasites mainly sit in the grass, waiting for the victim, they cling mainly to the pants, then through the holes they penetrate closer to the host's body and crawl up in search of a favorable place for attachment. Therefore, when going out into nature, especially during the season of tick activity, it is advisable to wear closed light-colored clothing, on which the parasite will be better visible - it will be easier to notice it and remove it from clothing in time. Pants must be tucked into socks so that the bloodsucker does not penetrate under them, and the shirt must be tucked into trousers. Shirt cuffs should fit snugly against the body. The neck and head must also be covered.
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For added protection, clothing is recommended to be treated with proven repellents: These chemicals are specifically formulated to protect against ticks.
However, what if the tick is still stuck? You should not panic - not all ticks (even in epidemiologically disadvantaged regions) are infected pathogens of dangerous diseases. And even if the parasite is infected, then not in every case its bite will lead to the development of a disease in humans.
Be that as it may, one should not relax either, since only the correct and timely measures taken will minimize the likelihood of undesirable consequences.
First you need to remove the tick. This is easy to do on your own, using, for example, tweezers or special tools for extracting ticks.
More information about the actions of a parasite bite is written in a separate article: First aid for a tick bite
Generally speaking, there is nothing difficult in removing a stuck tick. The main thing is not to pull out the parasite too sharply and press hard on it with your fingers.Firstly, the head of the tick can come off and remain in the wound, subsequently causing severe suppuration. Secondly, when squeezed, the tick will release a large amount of saliva and already infected blood into the wound - accordingly, if the arthropod is infected, the concentration of pathogens in the wound will greatly increase.
After removing the tick, the wound must be disinfected (it can be treated with alcohol, brilliant green, iodine or hydrogen peroxide). It is recommended to wash your hands thoroughly with soap. The extracted tick should be taken for analysis to make sure it is not infected and, if necessary, take appropriate measures (for example, emergency prevention of tick-borne encephalitis consists of injections of gamma globulins).
Useful video about the habitats of ticks and diseases carried by these parasites
How not to get into nature in places of the highest concentration of ticks and identify their clusters in the grass
