DEMODECOSES (Demodecoses), an invasive disease caused by endoparasitic. ticks of the genus Demodex fam. Demodecidae parasitizing in the sebaceous glands and hair sacs in various species of domestic and agricultural. animals are characterized by dermatitis, hyperkeratosis of the skin and progressive depletion. D. most severe in dogs, cr. horn. cattle and pigs are ubiquitous.
Etiology. Types of ticks - D. pathogens are specific for animals: in cr. horn. livestock parasitizes Demodex bovis, in horses - D. equi, in pigs - D. phylloides, in sheep - D. ovis. Morphology and their development cycle are largely similar to each other. The body shape is worm-shaped. There are undivided cephalothorax (protosome) and narrow abdomen (opistosome). Body color is light gray, cuticle striated in the transverse direction. Males dl. up to 0.3 mm, females - 0.5 mm, max. body width 0.06 mm. Proboscis lyre-shaped, gnawing type. Legs are short, three-membered, ending in claws. Larvae have no legs. Females are oviparous. Spindle-shaped eggs (D. canis, D. ovis) or oval (D. bovis) or irregularly oval (D. folliculorum). A larva hatches from an egg in 4–6 days, which moults in 2–3 days and becomes a protonymph, then in 2–3 days it molts again and turns into a teleonymph, and in 3-5 days – into an imago. The tick development cycle lasts 20–25 days. In cr. horn. livestock ticks form numerous. colonies (up to 4 thousand colonies, 5 thousand individuals each). In dogs, ticks from breeding centers migrate to the lymphatic. vessels and reach the walls of the intestine, ext. the environment of the eyes and parenchymal organs. Outside the host’s body live up to 8 days or more. Mobility is shown at t 30-40 ° C.
Epizootology. Infection occurs with the joint keeping of healthy animals with patients. Young animals are most susceptible, especially in poor housing and feeding conditions. Cr. horn. cattle get sick at the age of 3 months and older, dogs - at the age of 2 months, pigs - 3 months. The greatest spread of invasion occurs in the warm season, when sexually mature ticks leave the brood to the surface of the skin.
Symptoms Dense tubercles from 2 to K) mm in diameter appear on the skin of the head, neck, shoulder blades, sides of the chest, extremities. From the hole at the top of the tubercle, a sucrose stands out, and when pressed, the waxy contents. In dogs, focal redness, folding and thickening of the skin are noted. Itching phenomena are usually absent, animals reduce fatness due to intoxication and dysfunction of the skin. On the skin there are bald patches.
The diagnosis is based on the symptoms of epizootol. data and confirm the study of scrapings from the deep layers of the skin.
Treatment. Animals are treated with Acrodex in aerosol packages four times with an interval of 4-6 days, Dermatozole and Dewdrops four times with an interval of 5-7 days. The care items, the premises in which the sick animal was kept, are deacarinized (scalding or irrigation with a 2% suspension of sevine, 0.5% aqueous solution of chlorophos, 3% emulsion of nicochloran).
Prevention and control measures. Spend a monthly vet.-san. inspection of animals (from January to July). When isolating patients, the entire group of healthy animals that are on a common content is considered dysfunctional and subjected to treatment with acaricides. Patients are isolated.
Lit .: Parasitology and invasive diseases of agricultural Animals, ed. K. I. Abuladze, M., 1975.
Description:demodecosis is a parasitic skin disease caused by a tick-iron mite (demodex), which lives in the hair follicles and sebaceous glands.
Causes: direct contact, contact with infected objects.
Symptoms peels, peeling (especially on the bridge of the nose, in the ears, near the eyes and mouth, on the eyelids), loss of hair and / or needles, nodules, acne, red papulopustules.
Diagnostics: the diagnosis is established on the basis of the clinical picture and the detection of the tick in the contents of the pustules, the secretion of the sebaceous glands, in the scraping and scales from the lesions.
Treatment: 1. Sick hedgehogs have baths with ectodex / amitrase (twice with an interval of 10 days).
Young and / or weakened hedgehogs are treated with lindane (aerosol).
Grizovin (oral, 25-30 mg / kg every 24 hours).
In mild cases, dectomax is prescribed (0.3 ml / kg, subcutaneously).
2. The recovery is long, sometimes requiring several courses of treatment.
Disinfection of the cell and household items, the litter is replaced with a new one.
Prevention: compliance with personal hygiene. Literature:
2. Small medical encyclopedia
Literature:1. Glossary of medical terms
Credit: Portal Zooclub
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1. Demodecosis of cattle. Morphobiological characteristics of the parasite, diagnosis and therapeutic measures.
2. Demodecosis of carnivores. Morphobiological characteristics of the parasite, diagnosis of demodicosis, treatment and prophylactic measures.
Demodecosis carnivores is a widespread disease. Demodecosis is also called parasitic acne (acne), because often on the face in animals appear white pustules.
The causative agent of the disease is a thrombidiform tick. The first description of these ticks was made over 160 years ago. The first mention of ticks of the genus Demodex dates back to 1841, when Berger discovered them in human eels. Later in 1844, P Tulk and Megnin in 1877 reported finding such ticks in dogs.
To date, 143 species of demodectic mites have been described that parasitize on the skin of animals and humans.
According to many scientists, the causative agents of demodectic invasion are strictly specific to the host species. D. canis is not transmitted to cats, humans, and other mammals.
According to some authors, demodectic mites are evolutionarily similar to hair mites from the Miobidae family.
To date, the following systematic position of ticks has been adopted (About Connor, 1982)
D. brevis - localized in the sebaceous glands
D. folliculorum - localized in hair follicles
Since the name of the disease is determined by the generic name of the pathogen, which is read as Demodex, then the disease will be called demodicosis, not demodicosis.
The first report on the causative agent of cattle demodicosis was made by D. Gross in 1845 in a bulletin of the Moscow Imperial Society of Naturalists. Gross limited himself to mentioning the tick; he mainly reported on demodex ticks found in dogs, horses, and foxes. The first comprehensive work on cattle demodicosis was performed by W. Faxon in 1878 in America. Faxon was the first to describe the pathogen, sketch it, provide valuable data on this disease and give drawings of pathological skin changes caused by Demodex.
Demodecosis is a seasonal disease that occurs acutely, subacutely and chronically. The causative agent of cattle demodecosis is a thrombidiform tick - Demodex bovis, which has specificity.
It parasitizes in the hair follicles and sebaceous glands, forming colonies, feeds on lymph and tissue fluid. As a result of tick propagation, colonies are formed (Krulikovsky balls), i.e. localized lesions in the form of tubercles. In a demodectic colony there can be up to 10 thousand ticks, and colonies on one animal animal up to 4 thousand.
The body length of the female is from 0.200 to 0.278 mm. The female is more massive than the male. The body length of the male is 0.200-0.252 mm.
In D. bovis, the gnatosome is well defined, which is folded away from the podosome with 4 pairs of five-segmented limbs. The thoracic part is separated by a constriction from the abdominal opistosome. The female genital organ lies in the elongated groove-shaped recess of the cuticle, located below the second pair of limbs. In most females, it is covered by a fold of skin and cannot always be detected.
After mating, the male dies, and the female lays eggs and then she also dies. For 3-5 days, a larva from protonymph larvae emerges from the eggs, then a deutonymph and imago. The protonymph has a granular structure inside, and the imaginal individual is already forming in the deutonymph. The development cycle lasts under favorable conditions for at least 32 days. In one colony, several tick generations can change
The morphology of the tick metamorphosis phase morphology is a strictly oval egg shape, in contrast to the elongated forms in dogs, the egg takes on a bean-shaped shape as it matures. also the presence of a legless larva in the first stage of development.
Demodecosis k.s. is found in all climatic zones. The course of demodicosis has a pronounced seasonality and is in direct connection with the biology of the pathogen. The development of the disease is recorded in January, in the southern regions in December. Peak infestation is observed in late winter and spring. Demodecosis affects all age groups from 6 months of age, the most severely ill animals with reduced fatness. In the external environment, the tick persists for 5-6 days.
Clinical signs of cattle demodicosis are manifested by local and generalized tuberosity of the skin. Demodexes multiply in the hair follicles and sebaceous glands, causing atrophy, which leads to impaired skin functions, while mite vital products accumulate. In animals, nodules appear in the thickness of the skin in isolation from each other and the surrounding tissue in diameter of about 1 cm, mainly in the front of the body: on the head, neck, chest, shoulder blades. The nodules are tight. There is no itching of the skin. In cattle, demodicosis manifests itself in papular and generalized forms.
With a generalized course of invasion, depletion of animals may occur.
The diagnosis is complex.
With normal hairline, the animal is palpated, starting from the head, then moving to the neck, chest, chin, shoulder blades, upper forelimbs, elbow joints and abdomen.
If tubercles are found, the hair is cut into the skin, a sterile bloodletting Frank needle is inserted to a depth of 2-3 mm, then the contents are squeezed onto a glass slide, 50% glycerol or 10% alkali solution are dripped and examined under a small magnification of the microscope in a darkened field of view.
On dried skin, demodectic colonies are visible in the form of convex or concave rounded and oval spots of yellow color with a diameter of up to 10 mm. Their contents are microscopic according to the specified method.
Differentiate from hypodermatosis.
We treat animals using injectable forms, as well as oil solutions, ointments.
DEMODECOSIS of carnivores is a widespread, chronic, seasonal disease, which is manifested by focal skin lesions.
Significant research on this problem was conducted by such scientists as S.V. Larionov, F.I. Vasilevich, M.V. Rozovenko, B.A. Frolov, M.V. Shustrova, Drummond W., Fisher et al.
Different types of demodexes are morphologically similar to each other. The main distinguishing feature by which they can be differentiated are the size of ticks at different stages of development, the shape of the egg, the structure of the larva and the type of host on which they parasitize.
Morphology D. canis - cigar-shaped body, length 0.19-0.22 microns. The oral apparatus of adult ticks of the cutting-piercing-sucking type. The gnatosome is wide, protruding anteriorly, on the dorsal side, segments of the palps are visible on it.
On the ventral side, six very short papillae in the form of a cone are located on the terminal segments of the palps on both sides. Further between the palms are thin styletic chelicerae. They are enclosed in a case. At their base is a mouth opening, and just below there are paired breathing holes. The hypostome is peaked and with its help a tick is able to pierce the cell membranes. Chelicera make scissor-like movements, cut the cell membranes, the contents of which fall into the demodectic focus and serves as food for larvae and nymphs.
With a thorough study of adult gnatosomes, it was found that ticks have distinct lateral eyes of a regular classical shape, their central part is pigmented. The eyes are located on the sides of the gnatosome in the back and are clearly visible only from the side. Both eyes are interconnected by the infraorbital roller, after which the podosome immediately begins. In larvae and nymphs, organs of vision were not found.
The gnatosome, along with the main function of obtaining food while moving, actively helps the walking limbs.
From the ventral side, on the prodosome, 4 pairs of short cone-shaped with 5 mobile segments of the legs are visible. There are 2 claws on the legs of all legs. The legs of adults can be almost completely removed and extended in any direction, they can work synchronously, or each leg can move independently. The ventral part of the podosome is equipped with a coxosternal stylet.
At the level of 4 pairs of legs, between them is the genital opening, in the form of a longitudinal gap.
These ticks have weakly expressed sexual demorphism. In contrast to females in males, the body length is 0.16-0.18 microns and a narrower opistosome.
The respiratory system of demodectic mites is peculiar. In larvae and nymphs, only dermal breathing, in adult mites, it is carried out in two ways: skin and diffuse. Respiratory openings are located on the sides of the base of the hypostome. Thus, moving on the surface of the skin, they can navigate through the eyes and breathe atmospheric air.
Male and female mating occurs not on the surface of the skin, but in the colony. Females lay eggs from which, after 4-6 days, six-legged larvae emerge, which after 7-8 days turn into protonymphs, in a week they become deuterphs that can secrete sebaceous glands. go to the surface and spread out to other follicles. Then, after 10 days, the deuterymphs turn into adults.
Larvae and protonymphs are not able to move on the surface of the skin, therefore, like mite eggs, they are also located in the hair follicles and glands.
The duration of the development cycle depends on the season of the year, the general condition of the body, the conditions of detention and feeding. Moreover, the transition of one phase to another occurs through a complex process of body restructuring: histolysis at the beginning, when the destruction of organs and histogenesis occurs, i.e. the formation of organs of a new individual. On average, it lasts 25-28 days.
Ticks develop only in the hair follicles and sebaceous glands. Indeed, in the translation Demodex means "gnawing fat." It feeds on the secretion of a sebaceous iron 60% consisting of saturated fatty acids and cytoplasm of epithelial cells.
Females in papules live up to 10 months, males 3-5 days. The growth of papules lasts 3 weeks, and when their diameter reaches 10 mm, the "dome" is opened. When ticks leave old papules, and these are mostly females. Then they move on the skin for 2-3 days, looking for suitable follicles. When the ticks all go away, the cavity is overgrown with connective tissue or filled with dense fat.
Ticks are more active in the dark.
Demodexes are stable in the external environment. Outside the host’s body, they remain viable at a temperature of 19 C - 3-4 days,
at 1-5 C - 11-18 days. For a long time, ticks live in vegetable oil, petroleum jelly, cosmetic cream. Ether kills them instantly, alcohol in 3-4 minutes. All these features of the development of the tick must be considered when organizing therapeutic and preventive measures.
Demodectic invasion among dogs is widespread. Similar diseases are noted in most countries of the world. Smooth-haired breeds are most susceptible to the disease, of long-haired - shepherd, collie, sheltie.
Demodecosis occurs in acute and chronic form.
Initially, the acute course of the disease in dogs, especially puppies, proceeds in a scaly form.At the same time, bald areas with small scales of keratinized epidermis of gray color, which are easily removed, appear on the skin around the eyes, nose, and outer surface of the auricles. This period lasts 1-1.5 weeks. Dogs emit a characteristic odor. Next comes the period of papular manifestations of the disease. Papules (colonies) appear on the skin in the affected areas, by the 30th day they turn into visicles. Inside which accumulates a dense mass of gray. Their diameter is 7-10 mm. At 4-5 weeks from the onset of the disease, the vesicles burst. A crust forms in these places. In dogs, the appetite sharply worsens during this period, emaciation sets in. With the complete absence of treatment, improper treatment and maintenance of the animal, the disease becomes generalized.
An acute course can turn into a chronic one, in which the clinical signs are smoothed out. Even an improvement in the general condition may be observed, but after 1-2 weeks a relapse occurs. With the advent of new large bald patches of skin covered with a thick, tuberous crust, an ichorous smell emanates from dogs. Such a clinical picture can be observed during
A few years, but in the end, nevertheless, the animal dies. Throughout this period, a sick dog is a constant source of invasion for other dogs.
The pathogenesis of demodicosis is not entirely clear. It is clear that the suppression of the immune system (stress, endoparasites. The course, pregnancy) plays a significant role. In dogs, it proceeds in two forms:
localized (5 or less foci of skin lesions) and generalized (in young people from 3 months to 2 years) - juvenile demodicosis, in dogs older than 2 years - demodicosis of adult dogs.
GENERALIZED JUVENILE DEMODECOSIS.
Generalized juvenile demodicosis is hereditary. Which is determined by an autosomal recessive gene. Dogs who have had juvenile generalized demodecosis (both bitches and males) cannot be used for breeding. The most widespread theory is that a hereditary defect of T-lymphocytes leads to uncontrolled reproduction of demodex ticks, that TV in turn leads to even more serious deficiency of the immune system, then a secondary skin bacterial infection joins, also contributing to the further aggravation of functional disorders of T- cells. There is a certain vicious circle. With generalized demodicosis in adult dogs, it is necessary to look for the root cause that affects the immune system.
Typically, the primary pathology is endocrine disorders (hypothyroidism, diabetes), malignant neoplasms, chemotherapy, and the use of corticosteroids.
Demodecosis is more common (in 80% of cases) in purebred dogs. There is a pedigree predisposition to Scotch terriers, shar pei, all bulldogs, pugs). Sometimes you can trace the family predisposition.
The pathogenesis of feline demodicosis is even more unclear, but the manifestation of the disease (especially in cats older than 5 years) is almost always associated with the primary pathology provoked by immunodeficiency (viral infections, vaccinations, autoimmune diseases, malignancies).
Siamese and Burmese cats are predisposed to demodicosis.
Localized demodicosis in dogs is characterized by the appearance of areas of allopecia up to 5 cm, especially in the head area (around the eyes, in the corners of the mouth), on the forelimbs. Often in the affected areas, the skin peels, pigmented. Itching
is absent. In the case of a transition to a generalized form (10% of cases), extensive areas of the skin are affected and the process is often complicated by a bacterial infection - pyodemodecosis. Pyoderma
may be superficial or deep. Deep pyoderma may be accompanied by signs of syptemia. During this period, when most follicles are affected, demodexes migrate to the internal organs: liver, kidneys, spleen, etc.
In the internal organs, ticks do not parasitize, but are in a resting stage. If you do not provide the animal with qualified treatment, demodicosis passes into a complicated form.
Pododemodecosis - damage to the paws. It can occur as an independent disease, or as part of a generalized process. The skin of the fingers thickens, is pigmented, boils with hemorrhagic exudate are formed, the dog is lame.
In addition, demodex mites can cause inflammation of the outer ear, otodemodecosis. In pigs, otodemodecosis is part of a generalized process, in cats, as an independent disease.
In cats, skin changes (erythema, alopecia, oily seborrhea, pigmentation) occur in the head and neck. In the generalized form, complications of a bacterial infection are frequent, which is characterized by the appearance of papules, pustules, ulceration, and itching. In Persian cats, demodicosis can occur in a special clinical form - fatty facial (facial) seborrhea.
The diagnosis is complex, confirmed by the detection of a tick. To do this, make a deep scraping or incision of the affected area of the skin, the contents of which are placed in a drop of 50% glycerol or 10% NaOH, immersion oil, kerosene. To prepare permanent micropreparations, ticks are poured into the Fora-Berlese mixture. After taking the scraping, the wound must be treated.
If the animals have a generalized or complicated form. That can be investigated fecal masses by flotation method.
When viewing drugs, one should not only establish the presence of ticks, but determine which development phases prevail, and draw a conclusion about the duration of the disease. These data are necessary for the development of therapeutic measures.
Before proceeding with treatment, it is necessary to once again verify the correctness of the diagnosis, try to determine the cause of the invasion, to find out the conditions of the animals.
Treatment must be carried out comprehensively and consist of 2 directions.
Modern farm. The industry produces acaricides of various chemical groups.
Fosses are used in the form of aqueous emulsions or oil solutions of 0.5-2%. Do 3-4 treatments, an interval of 7-10 days.
It should be remembered that these drugs are toxic, reduce the level of cholinesterase in the blood.
Pyrethroids are used in the form of oil solutions and aqueous emulsions 0.05-0.075% 3-4 treatments, interval 5-6 days
Pharmamedin compounds of 0.02% concentration of an aqueous solution.
IWOMEC AVERSECT BAYMEK MOXIDEKTIN
1 ml per 50 kg, v / m. PC
Do not use collie, sheltie, bobtail and their crossbreeds.
We recommend the use of a complex preparation - Marasasd.