Animal anatomy, histology, pathological anatomy

BIBLIOGRAPHY
1. Zharov A.V. Pathological anatomy of animals. – St. Petersburg; M.; Krasnodar: Lan, 2013.

LECTURE No. 6.Topic: Pathomorphology of infectious diseases. Pathomorphology of sepsis, anthrax and pasteurellosis.

Plan:
1.Characteristics of infectious diseases.
2. Etiology and pathogenesis and pathomorphology of sepsis, differential diagnosis.
3. Etiology and pathogenesis of anthrax and pathomorphology, diagnosis and differential diagnosis of the disease.
4.Avian pasteurellosis etiology, pathogenesis and patanatomiya, diagnosis and comparative diagnosis.
Keywords:ulcer, diagnosis, hemorrhage, carbuncle, apoplexy,anginal,aspiration.
1). Infectious diseases are caused by certain living organisms that have a variety of pathogens. Microorganisms of many diseases enter the animal's body in different ways, for example, through food and water through the intestines, through the air through the lungs, through insect bites, through damaged skin and mucous membranes, and so on. This is called exogenous infection (external infection). Acute infectious diseases occur in all species of animals and birds. The disease is caused by bacteria and viruses. Pathogens often enter the body through the air. and spreads throughout the body, damaging the blood vessels of internal organs, damaging the parenchyma of organs, affecting the central nervous system, resulting in acute inflammation and bleeding causing necrotic changes. With such diseases, the body's resistance decreases and rapid death occurs. The causative agents of these diseases can be stored in the lungs, stomach and intestines of healthy animals. Under the influence of stress factors and other factors, they become pathogenic and cause disease. General changes develop in acute infectious diseases, but, of course, there are also changes characteristic of a specific disease, so you must be very careful when diagnosing the disease.
2). SEPSIS (Greek suppuration) is an infectious disease without a specific pathogen, characterized by damage to the spleen. Etiology and pathogenesis. Sepsis can be caused by staphylococci, streptococci, pasteurizers, salmonella, anthrax and yellow fever.
Clinically, purulent diseases are very difficult, sick animals often die. The acute form lasts 1-2 days.
Any sepsis is caused by the bacteria listed above entering the bloodstream. Bacteria multiply in the blood and produce toxins. They destroy endothelial cells of the vascular wall. They destroy red blood cells (hemolysis). The number of leukocytes in the blood increases. blood does not clot. Permeability forms in the walls of blood vessels, emigration of hematopoietic elements increases, and hemorrhage is observed, which is very typical for the spleen.
Types of sepsis: Coccal sepsis occurs as a result of cocci entering the blood. This sepsis is characterized by sepsis and pyemia. In sepsis, the source of sepsis is unknown, the temperature rises, and the activity of internal organs is disrupted. When opening the carcass of an animal that died of sepsis, the spleen enlarged 2-3 times, and a highly decomposed mass (humus) was observed in the pulp. Pyemic sepsis is characterized by long duration and metastasis. The combination of sepsis and pyemia is called septicemia.
Umbilical sepsis occurs as a result of bacteria entering through a damaged umbilical cord. This is observed during pathological childbirth.
Urosepsis is caused by the penetration of bacteria through the genitals. Most often this is observed with nephritis and cystitis.
Aspiration sepsis occurs as a result of the entry of these bacteria through the respiratory tract. More common in catarrhal bronchopneumonia.
Pathological anatomy of sepsis In the body of an animal that died of sepsis, the following changes are observed.. Yellowing of the subcutaneous tissue and mucous membranes also causes pinpoint hemorrhages, the blood does not clot and becomes dark red. The most characteristic change is formed in the spleen, the consistency increases up to 2-3 times in size, the consistency becomes cloudy, and foci of necrosis and hemorrhage appear in the remaining internal organs.
Sepsis, anthrax Sepsis is an infectious disease caused by microorganisms and their toxins circulating in the blood. The presence of microbes in the blood is called bacteremia. Depending on the type of pathogen, sepsis is distinguished: streptococcal, staphylococcal, anthrax, salmonella, etc. The place where microbes enter the body is called the gate of sepsis. There are wound (surgical), umbilical, post-burn, postpartum, etc. sepsis. Sepsis can occur in the form of septicemia, septicopyemia and chroniosepsis (pyemia). At autopsy, the most characteristic sign in most animals is an enlarged spleen, sometimes several times. Histological preparations show a lot of neutrophils, decaying red blood cells and brown pigment. An increase in lymph nodes is observed, especially regional to the septic focus. Hemodynamic, dystrophic and inflammatory changes are detected in the internal organs. Circulatory disorders are caused by increased permeability of the walls of blood vessels, especially capillaries. Anthrax is caused by the aerobic spore-forming bacillus Bac. anthracis. Sporulation occurs in the external environment with access to oxygen. In those less susceptible (pigs), or when infected with weakly virulent strains, local inflammatory processes first develop, and only with an unfavorable course does a general septic form of the disease occur. Based on the localization of primary changes, anginal, apoplexy, intestinal, pulmonary, skin and septic forms of anthrax are distinguished. The anginal form is observed in pigs, rarely in other animal species when infected through the gastrointestinal tract; manifests itself as serous hemorrhagic inflammation of the root of the tongue, tonsils, and pharynx. The intestinal form is found in all types of farm animals. The lesion can manifest itself in the form of limited areas of inflammation - carbuncles or in the form of diffuse hemorrhagic inflammation.
The diagnosis is made on the basis of clinical signs, epidemiological data, bacteriological studies and characteristic anatomical changes.
The comparative diagnosis or differential diagnosis of sepsis should be compared with the following diseases. anthrax, bronchopneumonia, interstitial, lymphadenitis, dermatitis, tympanic, pasteurellosis, salmonellosis. 3). Anthrax (anthrax) is an acute infectious disease characterized by hemorrhagic inflammation in the blood serum and septic changes in organs and tissues, including all species of mammals.
People also get sick; dogs, cats, pigs and poultry get sick less often.
Etiology and pathogenesis of anthrax. Bacteria are more common in cattle, in horses, in pairs of horses, blood-sucking insects also carry bacteria and enter the body. Bacteria spread through the blood into the body through the blood and vessel walls. Acute inflammation develops as a result of injury.
Pathological changes appear in animal corpses from anthrax. Various forms of anthrax occur. Changes occur depending on the course of the disease. The forms of anthrax are as follows.
1. Apoplectic form
2. Intestinal Shape
3. Lung shape
4. Skin or carbuncle shape
5. Septic form
1. Apoplexy is formed by this form of the disease in sheep, cattle and horses, the most common disease of the meninges and parenchymal serous-hemorrhagic inflammation.
Hemorrhages in the meninges. There is an accumulation of serum hemorrhagic exudate in the meninges, and changes in the internal organs are also characteristic.
2. The intestinal form is characterized by serous-hemorrhagic inflammation of the intestinal mucosa. Blood clots and hemorrhagic exudate appear on the intestinal mucosa. In some mammals, the large intestine and even the front part of the stomach are affected. This injury is also characterized by serum hemorrhagic inflammation and occurs in all animal species. We see bloody exudate in food.
3. The shape of the lungs is characterized by the development of serous-hemorrhagic bronchopneumonia in those lungs, which increases the size of the lungs and has a dark color.
This form of the disease is more common in ruminants, as hemorrhagic exudate appears on the cut surface, which turns red.
4. Skin or carbuncle shape. This form of the disease occurs in humans. Anthrax occurs when the pathogen enters through wounds in the skin of the palm when the anthrax touches the body of a deceased person. The bacterium multiplies where it falls, produces toxins and damages the blood vessels in the skin of the palm, resulting in the formation of dark red or dark blisters, the membrane of which is very thin and quickly ruptures, releasing serum exudate and forming wounds.
5. Form of sore throat. This form of the disease occurs only in pigs and is characterized by serum hemorrhagic inflammation of the lymph nodes and mucous membranes of the pharynx. In this case, the lymph nodes enlarge, the mucous membranes of the throat swell and appear dark red
6. Septic form This form of the disease occurs in all mammals and is characterized by the development of characteristic pathological changes in the body. The abdomen is swollen and does not harden. Caries develops. Bloody fluid leaks from natural pores. The blood doesn't clot. The mucous membranes and serum turn yellow, hemorrhages appear in the form of red dots. The most characteristic changes are in the spleen, the organ enlarges and becomes swollen, in the remaining internal organs necrosis, degeneration and purulence occur. seams appear. The subcutaneous clot turns yellow.
The diagnosis of anthrax depends on clinical signs, epidemiological data, bacteriological studies and anatomical changes. Other methods, as well as post-mortem methods, are used less frequently, since the spreed form of rod anthrax spreads to the external environment through the bite of a dead animal. Therefore, if anthrax is suspected, ear ointment is cut out from the skin of the ear and an anthrax stick is found under a microscope. If there is any doubt during rupture, the rupture should be stopped immediately and an ointment prepared from the blood of the spleen and heart and placed under a microscope for examination.
Comparative diagnosis Anthrax should be compared with the following diseases. It is necessary to distinguish between sepsis, bronchopneumonia, interstitial, lymphadenitis, dermatitis, tympanic, pasteurized, salmonellosis.
Anthrax differs from the diseases listed above by changes in the spleen and its causative agent.
4). Pasteurellosis affects cattle, goats and birds. It was a contagious disease and the microbe was first discovered by Louis Pasteur, so the disease was named after him.
Pasteurellosis is an acute infectious disease characterized by lobar pneumonia and swelling under the skin. Mammals and birds are most often affected. In addition, animals and birds of any age can become infected.
Etiology and pathogenesis. The disease is caused by pastrella. The pathogen is found in clinically healthy animals, pasteurella enters the body through the air and digestive tract, spreads through the blood, and forms an exudate that causes inflammation under the skin and muscles in the lungs.
Pat anatomy. The disease progresses differently in different animals. Pasteurellosis of cattle The disease with hemorrhagic septicemia takes two forms. 1. Acute or edematous form. 2. Chronic or chest form.
In the acute form of the disease, exudate accumulates under the skin of the head, neck, chest and legs. We also see exudates in the space between muscle fibers. We see these exudates when we feel areas filled with exudate and cuts. With this form of the disease, exudates rich in fibrinous-serous are formed.
The disease is sometimes chronic, with a characteristic change in the lungs called lobar inflammation. As the volume of the lungs increases, the consistency becomes softer. Dark reddish-dark spots form in the lungs, and fibrinous exudate, rich in erythrocytes and leukocytes, appears on the cut surface. The above changes occur in the pericardium of the heart and in the epicardium. The pericardium thickens, and in the epicardium we see fibrinous exudate absorbed by fibrin. With this form of the disease, the spleen and lymph nodes become enlarged.
Pasteurellosis of sheep. The disease is more common in lambs and is characterized by the formation of spotty red hemorrhages in parenchymal organs in the blood serum and on the mucous membranes, muscles under the skin, and in large sheep it is characterized by lobar pneumonia.
In pigs, the disease occurs in acute and chronic cases with lightning speed. When it passes at lightning speed, hemorrhage occurs in the epicardium of the heart and death occurs. When the disease is acute and chronic, it is characterized by lobar pneumonia, swelling under the skin and acute lymphadenitis.
Diagnostics and comparative diagnosis. The diagnosis is made based on clinical signs of the disease, bacteriological studies and pathological changes.
Pasteurellosis should be compared with the following diseases: anthrax, pneumonia (pleurisy), pleurisy, dermatitis; pasteurellosis differs from the causative agent of the diseases listed above.
3). Poultry pasteurellosis is an acute and even fulminant infectious disease characterized by sepsis and diarrhea, which affects birds of all species and all ages.
The etiology and pathogenesis of the disease is called pasteurellosis. The disease is also called cholera. The bacterium spreads through the blood, sepsis develops, the central nervous system and internal organs are affected, and rapid death occurs.
Pathological anatomy The disease progresses at lightning speed, hemorrhages are observed in the epicardium of the heart, in the acute course - pinpoint hemorrhages on the mucous membranes of the lungs and intestines, fibrinous exudate accumulates in the abdominal cavity. Foci of necrosis form in the organs, and the following pathological changes are observed in the organs.
1. Cyanosis (bruise) of a chicken earring.
2. Pleuropneumonia.
3. Serous-fibrinous pericarditis.
4. Hemorrhagic diathesis.
5. Foci of necrosis in the liver and myocardium.
6. Acute catarrhal hemorrhagic duodenitis.
7. Increases the size of the spleen (sometimes).
Diagnostics and comparative diagnosis. The disease is diagnosed based on clinical signs, bacteriological studies and pathological signs. The disease must be distinguished from plague and poisoning.
Animal pasteurellosis All types of domestic and wild animals are susceptible, including birds and humans. Carnivores and horses are resistant. Incubation period: from several hours to several days. Source of pathogen: sick and recovered animals. Routes of transmission: aerogenic, often alimentary. Hyperacute course - death without symptoms. In acute cases (edematous, thoracic, intestinal forms) - depression, fever up to 42°C, lack of appetite, mucopurulent discharge from the nose, conjunctivitis, cough, hemorrhagic enteritis, swelling in the intermaxillary space, death on days 2-5; In the edematous form: damage to the tongue, chest, croup, limbs, death within 1-2 days. In young animals - intestinal damage; in pigs - redness of the skin on the lower wall of the abdomen, symptoms of pharyngitis, fever, cardiac dysfunction, asphyxia, sometimes emaciation, weakness, cough, eczema. In hyperacute and acute cases, hemorrhagic diathesis is found in dead animals, multiple hemorrhages and inflammatory hyperemia are found on the mucous and serous membranes, the liver and kidneys are degenerated, the spleen is slightly swollen, the lymph nodes are enlarged and dark red in color. In the subcutaneous tissue there are serous fibrinous infiltrates. The lungs are swollen, with changes characteristic of the initial stage of lobar pneumonia. In the intestinal form, there is fibrinous-hemorrhagic inflammation of the stomach and intestines. In subacute and chronic cases, the corpses are emaciated and anemic. There may be dense fibrillar deposits on the serous membranes of the chest and abdominal cavities. The peribronchial lymph nodes are enlarged, hyperemic, with many hemorrhages. In the lungs, stages of red and gray hepatization are found, in 70 separate areas - foci of necrosis; in case of complications - purulent-fibrinous foci. The spleen is slightly enlarged, and there are foci of necrosis in the liver and kidneys. Pathogenic changes in chickens are almost the same as in mammals, and mainly depend on the course of the disease. Diagnostics. The spleen, liver, kidneys, affected parts of the lungs with lymph nodes and tubular bone are sent to the laboratory. The carcasses of small animals are sent whole. Imprint smears are made and stained with Gram or Romanowsky-Giemsa to detect bipolarly stained ovoid rods. A bioassay is carried out. Differential diagnosis. Distinguish from anthrax, emphysematous carbuncle, piroplasmosis, classical swine fever, erysipelas.
7 TOPIC.Clostridia. Pathomorphology of emkar and bradzot.