Pathogenic influence of parasitic on the body of a dog. Pathogenic effect of helminths on the organism of animals. Leishmaniasis - description of the disease

Infection can occur along with dirty hands, which is especially true for young children, who always put their hands in their mouths and grab everything in the street.

Violation of the immune system. Helminths produce metabolites that act as antigens. They can cause allergic or immunological reactions, lead to a weakening of the immune system.

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Between organisms of different species that make up one or another biocenosis, mutually harmful, mutually beneficial, beneficial for one and disadvantageous or indifferent for the other side and other relationships develop.

One of the forms of mutually harmful biotic relationships between organisms is competition. It occurs between individuals of the same or different species due to the limited resources of the environment. Scientists distinguish between interspecific and intraspecific competition.

Interspecific competition occurs when different types of organisms live in the same territory and have similar needs for environmental resources. This leads to the gradual displacement of one type of organism by another, which has advantages in the use of resources. For example, two species of cockroaches - red and black - compete with each other for a habitat - a human dwelling. This leads to the gradual displacement of the black cockroach by the red cockroach, since the latter has a shorter life cycle, it reproduces faster and uses resources better.

Intraspecific competition is more acute than interspecific competition, since individuals of the same species always have the same resource needs. As a result of such competition, individuals weaken each other, which leads to the death of the less adapted, that is, to natural selection. Intraspecific competition that occurs between individuals of the same species for the same environmental resources has a negative effect on them. For example, birches in the same forest compete with each other for light, moisture and soil minerals, which leads to their mutual oppression and self-thinning.

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The existence of some diseases is closely related to the natural focus. We are talking about a limited geographical area in which a pathogenic agent is located, which is an integral part of this ecosystem. This circulation is provided by the presence of reservoir animals (vertebrates) and vectors (blood-sucking insects, mites). As soon as a new recipient (recipient) of the disease, for example, a dog or a person, enters a natural focus, he is in danger of being attacked by a vector and transmitting the disease. In our conditions, this issue is relevant mainly in some viral and bacterial diseases (for example, tick-borne encephalitis, Lyma borreliosis). In tropical and subtropical areas, disease reservoirs in natural foci are significant, for example, trypanosomiasis in free-living animals (antelopes), from which the disease is transmitted to domestic animals.

The whole complex of pathological influences of a parasite on the host organism depends on many factors: the type of parasite, its virulence, abundance, habitat, developmental biology, and physiological state of the host. The concept of “host physiological state” alone includes a number of factors that may affect the development and pathogenic effect of the parasite on the animal organism, for example: the immune status of the organism, age, type of feeding and maintenance.
In the parasite-host relationship, the virulence (degree of pathogenicity) of a given parasite is also of great importance. It depends on the infectious properties of the parasite and on the susceptibility of the infected host organism. The virulence of parasites can increase with increasing temperature. For example, fasciolia adolescaria grown at 22-23°C caused acute fascioliasis in rabbits; grown at 15-17 °C caused only the chronic course of the disease.
Pathogenic effects on the animal body caused by the parasite during infection can be divided into several groups: mechanical, allergic, toxic, trophic and inoculatory.
The mechanical effect of the parasite on the host organism is determined by its habitat and developmental biology. It is clear that the localization of the helminth in the intestinal cavity is less noticeable than in the liver or brain. In addition, one should take into account the migration of larvae (in ascarids) according to the ascarid or non-ascarid type. The mechanical effect of ticks during parasitism on the skin of cattle is less pronounced than during the migration of larvae of subcutaneous gadflies in the thickness of the muscles and skin of infected animals. The localization of large bubbles of echinococcus in the parenchymal organs of animals, coenurosome in the brain of a sheep, dioctophyme in the renal pelvis of a dog, dirofilaria in the ventricles of the heart and atrium of carnivores causes atrophy not only of individual parts, but of the entire organ.
Vuchereria (round helminths 4 to 10 cm long) are localized in the lymphatic vessels and nodes of a person, which makes it difficult for the normal circulation of the lymph and contributes to the growth of connective tissue, ending with elephantiasis of the limbs, chest and scrotum. Some helminths (moniesia, ascaris) clog the intestinal lumen, thus violating the integrity of the mucosa, atrophy of epithelial cells, Brunner's glands, etc. Protozoa, parasitizing in erythrocytes or epithelial cells, significantly destroy them.
It should be noted that mechanical changes in organs and tissues, as a rule, lead to violations of their numerous functions. Therefore, this process should be considered as a morphofunctional effect of parasites.
The allergic effect of parasites lies in the fact that in the process of life they secrete metabolic products, secretion and excretion, which primarily have the properties of allergens. Allergens of somatic origin are released during the period of molting of larvae and their death in the organs and tissues of the host, during the destrobilation of cestodes during elimination from the body. Helminth allergens are complex compounds - polypeptides, proteins, polysaccharides and glycolipids. Under their influence, an allergic reaction (eosinophilia) occurs in the body of infected animals, and immunity of varying degrees of tension is developed.
The toxic effects of parasitic organisms are generally poorly understood. So far, no one has been able to isolate toxins from helminths. Nevertheless, in the chronic course of helminthiases as a result of metabolic disorders in sick animals, toxicosis is often noted. In sick animals, the general condition worsens, appetite decreases, the function of the gastrointestinal canal is upset, the number of erythrocytes and hemoglobin content decrease.
Indicators of toxicosis also consider a decrease (depending on time) in the content of cholinesterase in the blood serum, an increase in the number of pathologically glowing leukocytes. Putative helminth toxins (various substrates) are capable of exerting a cytopathic effect on artificially grown cells (transplanted human amnion cells), Hp-2 cancer cells, primary trypsinized human embryonic fibroblast cells, and chicken fibroblasts.
With a massive attack of midges in cattle and horses, under the influence of hemolytic poison, simuliotoxicosis develops. In sarcocysts (protozoa), the toxin sarcocystin has been isolated, which causes tissue necrosis in many laboratory animals. Local manifestations of the toxic effects of helminths are expressed in dystrophic and necrotic changes in tissues in the places where the parasites are located. So, with eurytremosis of sheep in the pancreas, one can observe necrosis of the duct wall with complete smoothing of all structural elements. Degeneration of the sarcoplasm with loss of striation and clumpy decay is noted in trichinosis.
Trophic influence is an integral property of the parasite. If the parasitic organisms known to us consumed substrates such as excreta or undigested food that the host does not need, then they should be considered some kind of commensalism. The ways of feeding and the food that parasites consume from the host organism are diverse and not fully understood.
In general, cestodes, as mentioned earlier, feed on the entire surface due to the structure and adaptability of helminths to use the host's digestive enzymes. Trematodes have a developed digestive system, and to a certain extent they are able to digest with the help of specific enzymes a variety of types of substrates: blood, tissue juices, mucus, epithelium, etc.
Parasites with a large biomass, of course, use a significant part of the food from the host organism. They consume not only the end products of the breakdown of proteins, carbohydrates, fats, but also vitamins, hormones, macro- and microelements. It is possible that certain enzymes and a number of substances stimulate the development and maturation of parasites. The use of vitamins by helminths is quite large. For example. O. I. Rusovich (1990) found that in 1 g of raw tissue of mature segments of moniesia, the concentration of vitamin B12 reached 4.988 ± 0.21 ng - approximately the same as in the blood of healthy lambs - 4.318 ± 0.05 ng / ml.
The inoculative effect of parasites is aimed at ensuring that the larvae of many helminths (dictyocaulus, ascaris, strongylidae, strongyloides), insects (subcutaneous and gastric gadflies) or young fascioli, paramphistomum, etc., during the period of tissue migration, transfer various species to many organs and tissues of the host microorganisms. Echinococcus larvae were found to be contaminated during migration of parenchymal organs of animals. Many dipterous insects, when sucking blood, inoculate healthy animals with pathogens of infectious diseases. Eimeria during the period of schizogonal development, destroying intestinal epithelial cells, open access for microorganisms to the deep tissues of the host. As a result, the body is seeded with various microbes, which often complicates the course of invasive and infectious diseases.
Control questions and tasks. 1. What is the essence of parasitism?
What are the goals and objectives of veterinary parasitology? 3. What scientific schools of parasitologists operate in the CIS countries? 4. Tell us about the origin of parasitism, the species diversity of parasites and their hosts.

There are morphophysiological and biological adaptations:

Morphophysiological adaptations:

- regressive: reduction of organs of movement and some organ systems (circulatory, respiratory); simplification of the structure of the nervous system and sensory organs.

Biological adaptations:

Improvement of various forms of asexual reproduction (schizogony);

Complex cycles of development with a change of hosts and the presence of several larval stages (flukes);

Migration of larvae through the host organism (roundworm).

The following forms of manifestation of specificity are distinguished:

2) topical: certain localization in the host (head and pubic lice);

3) age(pinworms and dwarf tapeworm more often affect children);

4) seasonal(outbreaks of amoebic dysentery are associated with the spring-summer period).

Exam ticket 33

Types of interaction of allelic genes: complete dominance and incomplete dominance (patterns of splitting, examples).

1. Complete dominance:A>a- when one gene completely suppresses the action

another gene (Mendel's laws are fulfilled). At the same time, homozygotes for a dominant trait and heterozygotes are phenotypically indistinguishable (yellow peas).

2. incomplete dominance AA=Aa=aa- the dominant gene does not completely suppress the recessive gene (Fig. 6.6). Heterozygous individuals carry their own trait. In the case of incomplete dominance, the 1:2:1 genotype split coincides with the 1:2:1 phenotype split (red, pink, white).

3. Overdominance. AA< Аа

The dominant gene in the heterozygous state manifests itself more strongly than in the homozygous state. For example: AA - flies are less prolific and tenacious than Aa. (recessive lethal mutation in flies, the phenomenon of heterosis in plants).

4.Co-dominance A1+A2=C

The two alleles are equivalent and when combined create a new trait. A classic example is the 4th blood group in humans.

5. Allelic exclusion. When different genes appear in different cells in the same individual. For example, when one of the X chromosomes is inactivated in women, vitiligo appears in some areas of the skin - areas with a mutant X chromosome. X * x (vitiligo) and x * X (normal)

Influence on the human body of abiotic factors (light, temperature, humidity, noise, etc.). Formation of biological rhythms under the influence of sunlight.

All environmental factors are divided into abiotic, biotic and anthropogenic.

Abiotic factors

Abiotic factors include light, temperature, humidity, pressure, chemical composition, etc.

Light is the primary source of energy. Almost all of the energy that comes to Earth comes in the form of solar radiation, which consists of visible light, ultraviolet and infrared rays. Light has a great signal value and causes a regulatory effect on the body. Due to the rotation of the Earth around its axis (24 hours) and around the Sun (365 days), rhythmic processes occur in all living organisms - photoperiodisms. As a result of adaptation to these rhythms, the corresponding biological rhythms of living organisms are formed:

1. Daily rhythm (24 hours - fundamental rhythm - alternation of sleep and wakefulness. Formation of daily rhythms in newborns - daily routine, decrease in rhythms in old age - insomnia), An example of photoperiodism is a change in the mitotic activity of cells depending on the time of day: in animals with daytime way of life - increase at night and vice versa.

2. Annual rhythm (365 days - a change in the reproductive capacity of a person, an increase in sexual activity in spring and summer, a decrease in autumn and winter).

3. Cycles of solar activity (2. 3, 5, 11, 35 years). Every 11 years, epidemic diseases appear.

Temperature affects the speed of physical and chemical processes in living organisms. Most animals are poikilothermic, i.e. their temperature depends on the ambient temperature (cold-blooded). Animals with a constant body temperature are called homeothermic(warm-blooded animals, mammals - 36-37C, birds - 40C).

Organisms are able to adapt to changes in temperature. There are biochemical, physiological, morphological, behavioral adaptation. Biochemical processes include the restructuring of metabolic processes, for example, the accumulation of carbohydrates in plant cells in autumn, which increase frost resistance. Physiological include the ability to thermoregulate, i.e. heat transfer regulation. For example, the ability of animals to sweat. Morphological refers to a change in shape. For example, according to Bergman's rule, when moving north, the average body size of warm-blooded animals increases.

Biological rhythms (biorhythms) are characteristic of all levels of organization of living matter - from molecular and subcellular structures to the biosphere. It is generally accepted that they are of an endogenous nature, but at the same time are closely related to periodic changes in the external environment, the so-called time sensors (photo-, thermo-, baro-periodicity, fluctuations in the Earth's magnetic and electric fields, etc.), the interaction of biological rhythms with periodically fluctuating conditions of the external environment ensures the unity of animate and inanimate nature. Biological rhythm is one of the mechanisms that allow the body to adapt to changing living conditions. Such adaptation occurs throughout our life, because the external environment is constantly changing, since the inanimate nature surrounding us is rhythmic. There is a change of day and night, seasons succeed each other, a cyclone replaces an anticyclone, solar activity increases and decreases, magnetic storms rage, people move from one time zone to another - and all this requires the body to be able to adequately adapt. Only with the synchronous work of biological rhythms is a full life possible.

It is important to take into account the synchronization of endogenous clocks with the surrounding time in professions associated with shift work, also among pilots, astronauts, etc.

Chronobiological patterns are important in the development of diseases. Biorhythms occurring in the body affect the effectiveness and toxicity of drugs, so taking into account time factors in drug therapy has become a necessity today. Further study of chronobiological patterns will contribute to the improvement of the therapeutic and prophylactic process in medicine.

Scabies pruritus: systematic position, morphology, development cycle. Method of invasion and localization in the host organism, pathogenic action. Prevalence in the Republic of Bashkortostan. Diagnostic methods. Public and personal prevention of scabies.

The female mite per day gnaws passages up to 2-3 mm long in the thickness of the stratum corneum of the skin (Fig. 93). Scabies mite moves look like straight and winding thin strips of whitish color 5-8 mm long. They slightly rise above the skin and resemble a healed scratch. Dark dots are visible along the course - holes. For better differentiation, the skin can be smeared with iodine tincture and wiped. At the blind end of such a passage, a bubble is visible, where the tick is located. To confirm the diagnosis of scabies, the vesicle and cover of the scabies are opened with a scalpel, the resulting material is transferred to a glass slide and microscoped.

Scabies itch feed on host tissues, irritate nerve endings, cause severe itching. When scratching, the passages are opened with nails and ticks are carried throughout the body. Infection of people occurs through direct contact with patients or their belongings.

• Leishmaniasis - description of the disease
• Forms of leishmaniasis - their symptoms and causes
• Leishmaniasis - high-quality treatment of the disease
• Complications
• Disease Prevention Measures

Where is leishmaniasis common? Leishmaniasis in humans and animals is most widespread in hot countries, for example, in Africa, India or South America. Oddly enough, the disease mainly has a geographical distribution in more developed countries and territories, but sometimes it also occurs in poor areas.

Leishmaniasis - description of the disease

Leishmaniasis is a transmissible infectious disease that is provoked by protozoa. They can affect humans and animals, as the carriers of the disease are mosquitoes. By biting an infected patient, female insects transfer the infection to a healthy organism. It is worth noting that outbreaks of the disease occur from May to November, this is due to the fact that at this time mosquitoes are active.

Modern medicine diagnoses leishmaniasis in almost 90 countries of the New World, which clearly indicates the prevalence of infectious pathology. With this in mind, experts recommend following elementary preventive rules and treatment methods. Unfortunately, these methods are not available to poor countries.

Forms of leishmaniasis - their symptoms and causes

Experts divide leishmaniasis into two types of major diseases. The main symptoms of the pathological process, as well as methods of treatment, depend on them. However, regardless of the disease, it is important to consult a doctor at the first symptoms. The infection spreads rapidly and affects a healthy body. If treatment is not started in a timely manner, the infection will increase its effect on the body, which will lead to serious complications.

The incubation period of visceral leishmaniasis is quite long from 20 days to 3 months, so often the development of the disease is not associated with an insect bite and the wrong therapy is prescribed. However, if you pass the necessary tests, the disease is immediately diagnosed. Treatment is further complicated by the fact that the first signs of the pathological process may appear only after a few months. However, clinical manifestations are always quite bright:

• general weakness and malaise;
• the patient gets tired quickly;
• a significant increase in the spleen (the organ can occupy half of the abdominal cavity);
• appetite decreases;
• body temperature rises to 40 ° C;
• disruption of the digestive system;
• develop cardiovascular complications;
• mucous membranes gradually begin to die off;
• the skin becomes gray, ulcers form in some areas;
• enlarged lymph nodes.

The first sign of infection is the appearance of a small tubercle at the site of the bite, which is covered with a dry scale on top.

However, a characteristic symptom of the disease is a constant enlargement of the liver and spleen. If high-quality treatment is not started in a timely manner, then these organs will occupy most of the abdominal cavity, displacing all the others. This violation will provoke serious complications, for example, ascites (abdominal dropsy) or an increase in the pressure of the intra-abdominal veins, which makes it difficult for blood flow and the veins increase.

1. Anthropogenic leishmaniasis (urban type). The incubation period lasts up to 8 months. Initially, a small hard tubercle appears at the site of the bite, gradually it begins to increase in size. Under the tubercle, the skin begins to acquire a dark brown hue, and after 3 months dry crusts appear. As soon as the crusts fall off, a round ulcer with a purulent coating is formed. The edges of the wound are constantly inflamed, which leads to an increase in the diameter of the ulcer. Complete healing of the wound occurs about a year after the bite. For all the time of the disease, from 1-10 sores appear on the body. As a rule, they form on open areas of the body that are accessible to mosquito bites. For example, on the face, arms or legs.
2. Zoonotic or rural cutaneous leishmaniasis. The duration of the disease is shorter, it is about 2-5 months. A small tubercle appears at the site of the bite, which quickly increases in size. After a few days, it reaches up to 2 cm in diameter. At the initial stage, tissue begins to die in the center of the bite, which provokes the formation of an ulcer. The wound quickly spreads to neighboring parts of the body, it can reach up to 5 cm in diameter. In some cases, multiple ulcers may appear. They are small in size, but their number can be from several tens to hundreds of pieces. Ulcers are rounded, inside they are filled with pus. After 3 months, the wounds gradually begin to clear, and after 5 months they are completely cured.

Regardless of the type of disease, it is urgent to consult a doctor and begin timely temporary treatment. Otherwise, the disease will only develop and can lead to serious complications, and in some cases even death.

The final diagnosis of the disease can be made after a thorough examination by a specialist and additional laboratory tests. To accurately diagnose the disease, the patient is prescribed a number of such tests:

• laboratory scraping from the affected area of ​​​​the body (ulcer or tubercle);
• microscopic examination of a drop or smear according to Romanovsky-Giemsa;
• bone marrow puncture or biopsy of the spleen, liver;
• serological studies (ELISA, RSK).

Thanks to the research obtained, the specialist will be able to establish an accurate diagnosis. On the basis of which high-quality treatment will be prescribed, which will lead to a speedy recovery.

Leishmaniasis - high-quality treatment of the disease

Therapy for cutaneous and visceral leishmaniasis is performed in a hospital under the strict supervision of medical personnel. The method of treatment is selected individually, for each patient, depending on the severity of the pathology.

In the visceral form of the disease, conservative methods of treatment are initially recommended, which include such medications:

• Neostibason;
• Glucantim;
• Treatment with Metronidazole;
• Solustibazan, Solyusurmin, Stibanol, Pentostan;
• Lomidin.

If these drugs do not help and the patient's condition is not satisfactory, then the therapy is supplemented with antibiotics. However, if necessary, surgery is recommended to remove the spleen.

If a patient has been diagnosed with cutaneous leishmaniasis, then he is prescribed such medications for treatment:

• antibiotics (ceftriaxone);
• Aminoquinol, Glucantim, Antimonil;
• Urotripin;
• Berberine sulfate.

Complement drug therapy with effective procedures that allow you to eliminate crusts and heal the ulcer. The patient is recommended to undergo a course of electrocoagulation and cryotherapy.

Complications

Complications will develop or not, directly depends on the severity and methods of treating the pathology. We can definitely say that the later the disease was diagnosed and treatment started, the more serious the consequences will be. With the visceral form of infection, the disease can cause such unpleasant complications:

• dysfunction of the liver;
• anemia;
• DIC syndrome;
• ulcers appear in the digestive organs.

If cutaneous leishmaniasis is found, then a complication can provoke re-infection, in which the cells die. In this case, it is important to continue quality treatment.

Disease Prevention Measures

Prevention is the best treatment for any disease, and leishmaniasis is no exception. What is the main factor limiting the spread of infection? To protect yourself from the development of the disease, a person must follow simple rules:

• infected animals must be treated or euthanized;
• keep the house clean and eliminate moisture;
• mosquitoes are carriers, so you need to use effective insect repellents;
• install mosquito nets or other items;
• timely diagnosis and treatment of the disease;
• increase immunity, especially for those who travel to dangerous areas.

The above rules will help protect the body from infection with leishmaniasis. However, if infection does occur, you should immediately consult a doctor and begin timely treatment. Take care of yourself and be healthy!

Leishmaniasis Leishmaniasis in humans: symptoms and treatment

Leishmaniasis Treatment of visceral leishmaniasis

Leishmaniasis Cutaneous leishmaniasis: treatment and prevention

Leishmaniasis Leishmania life cycle

At the present stage of development of immunology, the body's ability to develop immunity to worms is being studied. Scientists have become interested in helminths not so long ago, but have already established a host response system to helminthiasis. When worms start in the body, the human immune system begins to produce antibodies in order to overcome intruders. The danger of worms is that over time they adapt to the internal environment of the human body and thereby affect the immune system.

• primary (congenital);
• secondary (acquired).

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Types of antihelminthic immunity

• resistance to toxins (which are produced by worms);
• resistance to tissue antigens.

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Factors that determine host resistance

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Can worms impair the immune system?

Unfortunately, due to their evolution, worms have learned to influence the host organism. This is due to the fact that helminths are stronger than other bacteria and the body cannot completely overcome them. Although the stay in the intestines (or other organ) for the "guests" becomes worse, they adapt and over time have a negative impact. Worms weaken the immune system and a person exposes himself to infection with more serious diseases.

If symptoms of helminthiasis appear, consult a doctor

Despite this, sometimes there are benefits from parasites. For example, the patient's body is prone to an allergic reaction to some components. When a flatworm enters such an organism, antiparasitic immunity is formed and the allergy disappears. Other types of worms eliminate intestinal diseases (colitis, irritable bowel syndrome). This does not mean that you need to stop washing vegetables and neglect the rules of hygiene. Helminths can and should be removed, because there is a risk of contracting dangerous diseases and a person often gets sick with colds and flu. In addition, the state of health worsens, weakness, dizziness, drowsiness appear.