Ticks: structure, life cycle, role in the transfer of diseases of domestic animals — About animals

Dog tick

Ticks these are the most common external parasites of many animals, including cats. The tick does not belong to insects, like flies, fleas or lice, but to arachnids. In nature, there are approximately 850 species of ticks. According to the structure of ticks, they are divided into 2 families — Ixodidae and Argasidae.

Ixodid ticks. The ixodid tick family includes ticks covered with hard shields and therefore called hard ticks.

To the genus Ixodes includes the main carriers of tick-borne encephalitis and borreliosis — taiga tick and canine tick. (People call them encephalitis ticks). The bites of these ticks are most often exposed to people in the temperate zone of Eurasia. A taiga tick is common in Siberia, a canine tick in Europe. A typical biotope for ticks I. persulcatus are primarily humid shaded forest areas. In the eastern regions of the European part of Russia, both types of ticks are found. I. persulcatus, the spread of which covers the territory from the Baltic to the Far East

Argas mites. To the family Argasidae Argas or soft ticks are included. There are no shields on their body. The head of these ticks is located on the inside of the body, so if you look at the tick from above, then it is not visible. Soft ticks are fewer than hard ones. Most famous of them Otobius megnini or an ear mite. It is usually attached to the ear of an animal.

The anatomical structure of ticks. In ticks that have not reached puberty, 3 pairs of legs, in adults — 4 pairs. Wings are missing. Ticks have a sensory device called the Haller organ. With its help, ticks smell, temperature, humidity.

What do ticks eat? The diet of ticks consists only of blood — human, dog, cat and much more. They need blood in order to successfully develop at every stage of the life cycle.

What does the tick life cycle consist of? Most ticks in 2 years of life feed on the blood of three different hosts. All ticks go through 4 stages of the life cycle: egg, larva, nymph and adult.

Let us consider, for example, the life cycle of a black-footed tick (Ixodes scapularis).

In spring, adult females of the black-footed mite lay eggs on the ground. Each female tick lays approximately 3,000 eggs.

In late summer (depending on humidity and temperature), larvae emerge from the eggs. Larvae, which are smaller than the point at the end of this sentence, find the animal (the first owner, usually a bird or a rodent), feed on its blood for several days, then fall off and fall back to the ground. In black-footed mites, this usually occurs in August. In the ground, a well-fed larva passes into the next stage, which is called a nymph.

In the spring, nymphs become active and look for a second host — a rodent, pet, or person to pump blood. After that, it falls to the ground, then molts and turns into an adult.

In autumn, adult females and male ticks look for another animal (the third owner — a rodent, deer, domestic animal or human) feed on its blood and reach puberty. After eating, the males and females are again on the ground. Males die, and females hibernate and lay eggs in spring, completing the cycle. If in the autumn an ​​adult does not find a host, then it has to winter in foliage until spring, when it still manages to eat, reach puberty and lay eggs.

Different types of ticks are active at different times. For tick activity peaks in your area, contact your local health department.

What diseases do ticks carry?
— Pyroplasmosis.
— Theileriosis.
— Ehrlichiosis,
— Hemobartonellosis in cats and dogs,
— Hepatozoonosis,
— Lyme disease
— Tick-borne paralysis,
— Tularemia in cats and dogs.

Credit: Portal Zooclub
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29. Order Ticks, their classification, morphological characteristics. Tick ​​life cycles. The role of ticks in the development of human parasitic and infectious diseases.

Troop Ticks. Ticks — dwellers

Belong to the subtype Helitserov, class Arachnids. Representatives of this detachment have an unsegmented body of oval or spherical shape. It is covered with chitinized cuticle. There are 6 pairs of limbs: the first 2 pairs (chelicera and pedipalps) are brought together and form a complex structure of the proboscis. Pedipalps also act as organs of touch and smell. The remaining 4 pairs of limbs are used for movement, these are walking legs.

The digestive system is adapted for feeding semi-liquid and liquid foods. In this regard, a pharynx of arachnids serves as a sucker. There are glands that produce saliva that hardens when a tick bites.

The respiratory system consists of leaf-shaped lungs and trachea, which open on the lateral surface of the body with openings — stigmas. Tracheas form a system of branched tubules that fit all organs and carry oxygen directly to them.

The circulatory system of ticks is built less simply in comparison with other arachnids. They either do not have it at all, or it consists of a saccular heart with holes.

The nervous system is characterized by a high concentration of its constituent parts. In some species of ticks, the entire nervous system merges into one cephalothoracic ganglion.

All arachnids are dioecious. At the same time, sexual dimorphism is quite pronounced.

The development of ticks proceeds with metamorphosis. A sexually mature female lays eggs, from which larvae with 3 pairs of legs hatch. They also have no stigma, trachea or genital opening. After the first molt, the larva turns into a nymph, which has 4 pairs of legs, but, unlike the adult stage (adult), the sex glands are still underdeveloped. Depending on the type of tick, one or several nymphal stages may occur. After the last molt, the nymph turns into an imago.

Among ticks, there are free-living species that are predators. There are species that are parasites of humans, animals and plants. Many diseases of cultivated plants are caused by ticks of various species. Some ticks have adapted to live in human dwellings. These are homemade ticks. Other ticks have adapted to temporary ectoparasitism (i.e., living on the surface of the human body and other animals). However, they still spend most of their lives in their natural habitat, so these species have not undergone a deep degeneration of the structure. These include representatives of the Ixodidae and Argasova families.

A small part of the species has adapted to constant parasitism in humans. It was they who underwent the most profound degeneration of the structure and adaptation to parasitism. These include itch itch (the causative agent of scabies) and acne zheleznitsa, which lives in the sebaceous glands and skin follicles.

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Scabies itch (Sarcoptes scabiei) is the causative agent of human scabies (scabies). Refers to permanent parasites of the person in whose body lives in the stratum corneum of the epidermis. The disease is widespread, as the parasite is inextricably linked to humans. Close species can also cause scabies in domestic and wild animals, but they do not have strict specificity with respect to the owner, therefore itch parasites of dogs, cats, horses, pigs, sheep, goats, etc. can parasitize humans. They do not live long, but cause characteristic changes on the skin.

The dimensions of the parasite are microscopic: the length of the female is up to 0.4 mm, the male is about 0.3 mm. The whole body is covered with bristles of different lengths, there are suckers on the limbs. The limbs are greatly reduced. The oral apparatus is adapted to gnawing moves in the skin of a person, where the female lays eggs (up to 50 pieces for a lifetime, which lasts up to 15 days). Metamorphosis also occurs here (in 1-2 weeks). To penetrate the skin, the parasite selects the most tender places: interdigital spaces, genitals, axillary cavities, stomach. The length of the course, which the female makes, reaches 2-3 mm (males do not make moves). When ticks move in the thickness of the skin, they irritate the nerve endings, which causes intolerable itching. Tick ​​activity intensifies by night. When combing, the ticks open. At the same time, larvae, eggs and adult ticks scatter along the patient’s linen and surrounding objects, which can contribute to the infection of healthy individuals. You can get scabies when using personal clothing, bedding and things of a sick person.

Lesions by these ticks are very characteristic. Straight or convoluted strips of off-white color are found on the skin. At one end, you can find the bubble in which the female is located. Its contents can be transferred to a glass slide and microscopic in a drop of glycerol.

Compliance with the rules of personal hygiene, maintaining a clean body. Early detection and treatment of patients, disinfection of their underwear and personal items, health education. Sanitary supervision of hostels, public baths, etc.

Zheleznitsa acne (Demodex folliculorum) — the causative agent of demodicosis. It lives in the sebaceous glands, hair follicles of the skin of the face, neck and shoulders, located in groups. In weakened people prone to allergies, the parasite can actively multiply. In this case, the ducts of the glands become blocked and a massive acne rash develops.

In healthy people with good immunity, the disease can be asymptomatic. The parasite is resettled when using shared linen and personal hygiene items.

The extruded contents of the gland or hair follicle are microscopic on a glass slide. You can find an adult parasite, larva, nymphs and eggs.

Compliance with personal hygiene. Treatment of the underlying disease that causes weakened immunity. Identification and treatment of patients.

3. Ticks — inhabitants of a person’s home

These ticks have adapted to live in human dwellings, where they find their livelihood. Representatives of this group of ticks are very small, usually less than 1 mm. The mouth apparatus is gnawing: chelicera and pedipalps are adapted to capture and grind food. These ticks can actively move around a person’s housing in search of food.

To this group of ticks can be attributed flour and cheese ticks, as well as the so-called home ticks — permanent

inhabitants of the human house. They feed on food supplies: flour, grain, smoked meat and fish, dried vegetables and fruits, desquamated particles of the human epidermis, mold spores.

All these types of ticks can pose a certain danger to humans. Firstly, they can penetrate with the air and dust into the respiratory tract of a person, where acaridosis causes the disease. Coughing, sneezing, sore throat, often recurring colds and repeated pneumonia appear. In addition, ticks of this group can enter the gastrointestinal tract with spoiled food products, causing nausea, vomiting, and upset stool. Some species of these ticks have adapted to live in an oxygen-free environment of the large intestine, where they can even breed. Ticks that eat foods spoil them and make them inedible. Biting a person, they can cause the development of contact dermatitis (inflammation of the skin), which are called cereal scabies, grocers scabies, etc.

Measures to control ticks that live in food are to lower humidity and temperature in the rooms where they are stored, since these factors play a large role in the development and reproduction of ticks. Of particular interest in recent years has been the so-called house tick, which has become a permanent inhabitant of most human homes.

It lives in house dust, mattresses, on bedding, in cushions, on curtains, etc. The most famous representative of the group of house mites is Dermatophagoi-des pteronyssinus. It has extremely small dimensions (up to 0.1 mm). In 1 g of house dust can be detected from 100 to 500 individuals of this species. In the mattress of one double bed, a population of up to 1,500,000 individuals can live simultaneously.

The pathogenic effect of these ticks is that they cause severe allergization of the human body. In this case, allergens of the chitin cover of the body of the tick and its feces are of particular importance. Studies have shown that house dust mites play a crucial role in the development of bronchial asthma. In addition, they can cause the development of contact dermatitis in individuals with increased skin sensitivity.

The fight against house dust mites requires the most frequent wet cleaning of premises, the use of a vacuum cleaner. It is recommended to replace pillows, blankets, mattresses from natural materials with synthetic ones in which ticks cannot live.

Inhabitants of forests, pastures, meadows. Active from early spring to late autumn, parasitize on large and small terrestrial vertebrates. The victim is found using thermo-, vibro- and chemoreceptors. The duration of blood sucking in a female is several days (6–7, up to 16), in a male it is less. A well-fed female lays from 100 to 10,000 eggs in crevices and cracks in the bark, and then dies. After 2–4 weeks, 0.6–0.8 mm larvae emerge from the eggs, having 3 pairs of walking legs and lacking the respiratory and reproductive systems. They feed on blood for 2–4 days, then turn into nymphs with a respiratory system and 4 pairs of hilogods. Nymphs after 3-5 days of bloodsucking turn into sexually mature forms (Fig. 38.3). The duration of the development cycle depends on the possibility of bloodsucking, temperature, and the type of tick (one-, two-, and three-year developmental cycles are possible; in taiga ticks, up to 5 years). Single-host species undergo a full cycle of development on the body of one host, in two-host species, the larvae and nymphs parasitize on one, and a mature individual on the other host, in three-host species, each form feeds on a new host.

Inhabitants of holes, caves, living quarters. They feed on the blood of any vertebrate that has entered the shelter. Bloodsucking lasts from 3 to 60 minutes depending on the ambient temperature. After feeding, the female lays several hundred eggs. Adult ticks feed repeatedly, laying up to a thousand eggs during their life, with a one-year interval. After 11-30 days, larvae emerge from the eggs. Metamorphosis is possible only after feeding, the duration of feeding the larva is up to several days. At a favorable temperature and timely nutrition, the development cycle lasts 128–287 days (Ornithodorus papilipes), in nature it usually takes 1–2 years. Due to the ability to long-term fasting (up to 10 years) and several nymphal stages (2–8), the development cycle can reach 25 years.

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Dog tick: photo

The dog tick belongs to arachnids and in its structure, appearance and movements you can really find a lot in common with spiders.

  • The size of a hungry tick varies in the range of 2–4 millimeters; females are usually larger than males.
  • The color of the back is brown, with a brown or almost black circle half the body from the head and below.
  • The body of the tick is flat; together with its head, it has a drop-shaped form.
  • The tick has 4 pairs of long legs.
  • Well-fed ticks increase in size to 1–1.2 centimeters in diameter.
  • The body becomes gray due to stretching of the tissues and blood inside the parasite.
  • The blood-soaked tick becomes round and resembles a glossy bean with short legs sticking out in front.

Fortunately, dog mites do not move as fast as some types of spiders, so if you notice an insect resembling a tick in your pet or yourself, you can just brush it away before the parasite finds a place to stick. If you doubt that you are faced with this particular species, look at what the dog tick looks like in the photo and, additionally using the description above, try to more accurately identify the pest.

Dog Tick: Life Cycle

Ticks are oviparous insects. The female, saturated with blood, lays at a time from several hundred to several thousand eggs. She places them at ground level — in humus, fallen leaves, topsoil, compost, firewood, dumped garbage, on tree roots and in other secluded places. Clutches look like clusters of small dirty yellow eggs, somewhat similar to small eggs.

  • The incubation period of eggs lasts from 2 weeks to 2 months.
  • Dog tick larvae are similar to adults, but they are smaller — up to 0.2 millimeters in length.
  • At this stage, the insect spends from 1 week to 1.5 months, and then turns into a nymph.
  • Nymphs also look like adult ticks, but they are still smaller — up to 1 millimeter in length.
  • To move from one stage to another, an insect needs to be nourished with blood, its viability at each stage depends on it.
  • Larvae feed on the blood of small rodents and burrowing animals that climb or live in the ground.
  • Nymphs are able to climb to the surface, but rarely rise above 20 centimeters from it, here larger rodents and animals are added to their diet.
  • After becoming an adult insect, the tick lives 1–2 years, brings offspring and dies.
  • In total, a dog tick is able to live up to 8 years.

The pace of growth of the dog tick and its life cycle as a whole depends on the climatic conditions where the insect lives, the characteristics of the current season and other external circumstances. The development cycle from hatching from an egg to breeding an adult can occur both in 1 year and stretch for 4-6 years. During cooling, ticks at any stage of development can fall into suspended animation and temporarily suspend their life until the onset of more suitable conditions for this. Adult insects, larvae, and nymphs can hibernate.

Dog tick: diseases

Biting various warm-blooded animals, ticks become carriers of diseases that infected their carriers. When bitten, ticks can transmit these bacteria and viruses to humans and animals. Many of them lead to death without treatment, and this is the main thing why any tick is dangerous.

A tick with a bite can transmit the following diseases:

  • Tick-borne encephalitis
  • Lyme Disease or Borreliosis
  • Tularemia
  • Marseille fever
  • Different types of tick-borne typhus
  • Babesiosis
  • Rickettsioses
  • Monocytic Ehrlichiosis

If, after a bite, these diseases are detected in the early stages and treatment is started even before the first symptoms appear, most often they can be completely cured. According to official statistics, mortality rates due to tick bites are low and mainly relate to isolated, deaf regions where people chose not to seek medical help at all or did it too late.

For early detection of diseases, the tick that has sucked in, after it is removed from the body, must not be destroyed, but submitted for analysis. If harmful viruses or bacteria are found in the insect, doctors will be able to start treatment before your first symptoms appear.

Dog tick: harm to humans

In addition to the danger of transmitting pathogenic viruses and bacteria that threaten human life and health, tick bites themselves can also cause many problems.

  • A person does not usually feel the moment of a bite immediately, but a pulsating pain may begin to appear over time.
  • If the tick is removed incorrectly, the head of the parasite may remain in the wound and the bite will begin to fester.
  • An allergy can appear on a dog tick bite, its intensity and which one it will depend on the individual characteristics of the body.
  • Tick ​​bites can be very itchy.
  • Combing them, you can additionally bring any infection into the wound with your own hands.
  • Scars and scars may remain in place of heavily combed bites.

With weak immunity, sensitivity and chronic diseases from a dog tick bite, it can:

  • Rise in temperature
  • Dizzy
  • Shortness of breath and other breathing problems
  • Feeling general weakness in the body
  • Nausea and vomiting appear
  • Feeling heavy chest

A dog tick is undoubtedly dangerous for humans, but it can be no less, and sometimes even more, a threat to pets.

Dog tick: harm to cats and dogs

Cats and dogs are ideal victims for ticks, as they live in redistributions of the same height as insects. From pets that were not protected from parasites, ticks can sometimes be removed literally in clusters. Most often, parasites bite animals in the auricle, in the head, withers, neck or stomach. Catsas a rule, they rarely pick up any diseases from ticks, except for feline babesias. For dogs, a dog tick can do much more harm.

Dogs may be infected. pyroplasmosis, encephalitis, anaplasmosis, monocytic ehrlichiosis and borreliosis, while in 98% of cases without medical intervention and the necessary treatment, the animal will die, so it is important to immediately contact a veterinarian and notice any signs of changes in well-being in a dog if it is bitten by ticks.


Taiga Biome

Taiga Biome Facts

Taiga Biome Description

The taiga biome is one that has very long and cold winters. They summers are short and they are cool in temperature. The cool air masses from the arctic can move in rapidly. The average temperature in the summer is from 64 degrees to 72 degrees. However, in the winter months it can be -14 degrees. Taiga biome makes up 29% of the world’s forest cover.

Climate From 64 to 72 °F. In winter -14 °F
Plants Coniferous, pines, oak, maple and elm trees.
Animals Mooses, lynx, bears, wolverines, foxes, squirrels.
Location North America and Eurasia.
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There is heavy snowfall in the winter months. During the summer it is humid and rainy. The average annual rainfall is approximately 33 inches for the taiga biome. There is often no cloud cover in this biome so the temperatures can drop very fast at night. It does warm up enough in the spring though for flowers to melt and the ice to melt into the ponds.

The taiga biome is the home of the needle leaf forest regions. It is a lonely existence in this area. As a result many of the animals in this area often suffer from struggles to find enough food to survive. It may surprise you to discover that this particular biome is the largest one in the world. You will find it over various areas of North America and Eurasia. The largest taiga biomes are found in Russia and Canada.

Taiga Biome Characteristics

There isn’t very much annual precipitation that occurs in the taiga biome. There is some though in the summer months. This tends to create problems due to the heavy bark found on the trees there. The outbreak of fires during the summer months in the taiga biome is very high. During the colder time of the year, there are extremely cool winds that make it hard to survive in such conditions.

The rich forest are of the taiga biome takes over where the tundra biome ends. During the longer parts of summer, there can be up to 20 hours of daylight given. The temperatures though can severely dip and rise over the course of any 24 hour period. Therefore, you must be ready for what this particular biome offers.

The quality of the soil found in the taiga biome is very poor. They lack the essential nutrients to support large trees. The soil is also very thin here due to the cold weather. The leaves that fall from the smaller trees though due offer a type of natural fertilizer that can be very beneficial to the soil. However, the needles from the evergreens have acid in them and that further result in the quality of the soil further deteriorating in those areas.

Taiga Biome Facts and Information

Taiga Biome Flora and Fauna

Due the fact that food sources are even more difficult during the winter, animals in the taiga biome have adapted to this. For example many of them migrate to warmer locations during the winter. They do so for shelter just as much as they do for the ability to find food. Other animals in the taiga biome remain there all winter. However, they hibernate so they don’t need to forage for food during the winter months.

There isn’t nearly as many plants or animals that live in the taiga biome as others. However, what you will find a huge abundance of are insects. Birds often come to the taiga biome to feed on these insects. They also will breed in this area before going back to their permanent location. It is believed that more than 32,000 species of insects live in this particular biome.

There are more than 300 species of birds found in the taiga biome. They nest in this area so that they can successfully feed on those insects. Studies show that only about 30 species of these birds remain there in the winter months. The rest migrate to warmer climates.

There are several types of animals that seem to do well in the taiga biome. Most of them are predatory animals that feed on other animals that also live in that biome. These animals include the lynx, bobcat, and wolverine. They are able to eat a variety of foods including elk, deer, mouse, rabbits, and squirrels.

The American Black Bear is found in the taiga biome. It consumes a variety of different foods including twigs, leaves, and plants. Only about ¼ of what they eat is in the form of small prey and left over carcasses. They do hibernate in the winter time so that they don’t have to forage for food during that difficult period of time in the taiga biome.

You will notice that many of the animals that live in the taiga biome are able to change their color based on the time of year. That helps them to remain camouflaged from predators. They also have thicker coats in the winter, and they will shed them in the summer months.

Coniferous trees are very common in the taiga biome. This is why it is often referred to as the boreal forest. These types of trees include Douglas Fir, White Spruce, and Hemlock. There are also lots of lichen and moss that grow in the taiga biome. They offer a great source of food for the insects that live in this environment.

The coniferous trees have long thin needles and they are known as evergreens. They have wax on the needles and that helps to offer them protection from the harsh winds of the taiga biome. These types of trees don’t shed their leaves during the winter either. Instead, they remain part of the tree all year long. You will also find that they are close together in this region. That helps them to avoid damage from the wind too.

The Balsam Fir also is found in the taiga biome. They can grow to be up to 80 feet tall which is remarkable. They can also end up living for up to 200 years. Depending on the location, many of the lower branches can die. However, the rest of the tree is still strong and thriving. These particular trees feed the might moose throughout the winter months. Without them, those animals wouldn’t be able to survive in the taiga biome.

Taiga Biome Characteristics

Taiga Threats

Everything is in careful balance between the plants and animals that live in the taiga biome. That is the way that it should be. However, actions from humans such as heavy hunting of the American Black Bear or Moose can cause problems. The cutting down of coniferous trees in the taiga biome can also prevent these animals from being able to find enough food to survive there.

The Balsam Fir trees are often cut down to be used as lumber. They are used to make logs for cabins, pulpwood, and even Christmas trees for the holidays. However, if they are cut away in too large of numbers then the taiga biome isn’t going to have that careful balance that it really needs for all living there to thrive.

Many regions of the taiga biome are threatened due to logging efforts. This is especially true in Russia and Canada. There are also issues with some of the insects living in these regions causing plagues among the trees. They can leave the trees brittle, prevent them from growing, and deplete them on the nutrients necessary for survival.


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