Causes, symptoms and treatment of foot and mouth disease in humans. Foot and mouth disease: course and symptoms of the disease. Foot and mouth disease in cattle. They are found in pigs, sheep, goats, and deer. Diagnosis, treatment, control and prevention measures

Foot and mouth disease (Aphtae epizoolicae) - acute, zoonotic viral infection, with a fecal-oral transmission mechanism, is characterized by aphthous lesions of the oral mucosa and lesions of the skin of the hands, occurring against the background of feverish-intoxication syndrome.

Foot and mouth disease has been known to man for more than 400 years, and its causative agent was first discovered in 1897 by Lefler and Frotem. In artiodactyl animals, profuse salivation and aphthous changes in the oral cavity, damage to hairless areas of the scalp, udder, as well as damage to the myocardium and skeletal muscles. Over time, similar symptoms began to be noticed in people who had contact with infected animals.

Pathogen of foot and mouth disease

The causative agent is an RNA-containing virus belonging to the family of picornoviruses (Picornaviridae: pico-small, rna-RNA), the genus of aphtoviruses (Aphtovirus). The foot and mouth disease virus is classified as a highly resistant group, because it is not affected by drying or disinfectants. Mountain pastures last a year, wastewater, on clothing and wool, as well as in sausages - 3 months, indoors - 2 months, in fresh milk at a temperature of 4°C - 15 days, frozen - for years, without loss of virulence. Inactivation of the virus occurs only when heated and when treated with 1-2% hot solutions of Na and K for 30 minutes, a 2% formaldehyde solution kills the pathogen within 10 minutes, and a 4% peroxide solution is also destructive. The effect of UVR is also destructive.

Due to its high contagiousness and resistance, the virus does not lose its relevance to this day. Foot and mouth disease is registered in many countries around the world and, according to the latest data (2003), every year about 70 countries around the world become unfavorable for this disease. Until 1989, periodic outbreaks of the disease were recorded in Russia. IN modern conditions, with sufficient preventive equipment, people practically do not get sick with foot-and-mouth disease, but foot-and-mouth disease causes great economic damage to livestock. In a matter of hours, one sick animal can infect hundreds. Sick animals must be destroyed.

Symptoms of foot and mouth disease in animals

Causes of foot and mouth disease infection

Source and reservoir - cattle, pigs, sheep, goats, very rarely - dogs, cats, horses, Domestic bird– infection occurs through close contact with sick animals and an environment contaminated with viruses (i.e. a place with a high contamination of the virus). A secondary role in the spread is given to rodents, flies and ticks. The mechanism of infection is fecal-oral (through food), contact and contact-household, i.e. either through direct contact with the aphthae of sick animals, or through contact with contaminated objects. For animals, the aerogenic route (airborne droplets) is also relevant. The predisposing factor is microtrauma on the skin.

The incubation period is 2-12 days, but on average 3-8 days. This period is considered from the moment the pathogen enters the body until the onset of symptoms. The gateway to infection is the mucous membrane or microtraumas skin- the pathogen penetrates through them and part of the pathogen remains there, and part is spread throughout the body through the blood. As soon as the number of microbes reaches a certain concentration (including at the gates of infection), a period of clinical manifestations occurs.

The period of clinical manifestations is an acute onset of the disease, without previous signs. FMD begins with a feverish-intoxication syndrome: chills, myalgia, a gradual rise in temperature over 2 days, reaching a maximum by the end of the second day - 38-40 ° C and this temperature remains for a week. Against the background of feverish-intoxication syndrome, symptoms gradually increase skin manifestations and the place where these changes occur depends on the area of ​​primary contact, i.e. it can be either the hands when caring for a sick animal or the oral cavity when consuming infected products).

Symptoms of foot and mouth disease on the hands

In the oral cavity, these changes are characterized by symptoms of stomatitis, burning in the mouth, redness of the mucous membrane of the lips/ gums/ larynx/ cheeks/ tongue with further swelling. Rhinitis, conjunctivitis, and urethritis may also occur in parallel.

As it spreads throughout the body, the pathogen continues to fixate on epithelial cells, secondary inflammatory changes appear on the skin of the hands (especially in the periungual area and interdigital folds), after 1-2 days specific inflammatory changes appear in the place where there was swelling and hyperemia - appear aphthae.

Aphthae are superficial ulcerations, painful on contact with any surface, making chewing and swallowing very difficult, and accompanying symptom is hypersalivation (increased salivation). Localization of afts is along the edge of the tongue, on the gums, on the palate and on the teeth. The size of these ulcerations can be from a grain to a pea.

Almost simultaneously, with an interval of 1-2 days, similar formations appear on inflammatory areas of the skin (periungual and interdigital areas). After 2-3 days from the moment of appearance, the aphthae open, forming erosions or ulcers, speech and swallowing become even more difficult, the lips and tongue become covered with plaque and crusts. Possible eruption, i.e. the formation of new aphthae, makes the disease protracted and prone to chronicity, since these ulcerations are often accompanied by a secondary bacterial infection.

Diagnosis of foot and mouth disease

According to clinical and epidemiological data;
Carrying out a biological test on guinea pigs;
Serological methods using RSK (complement fixation reaction) - for the quantitative determination of complement-fixing antibodies and antigen, in other words, for the identification of antigens. HRA (hemagglutination inhibition reaction) - determines the increase in antibody titer.

Treatment of foot and mouth disease

Etiotropic treatment is aimed at the use of broad-spectrum antiviral drugs (isoprinosine, arbidol), as well as immunomodulators and immunostimulants in the form of viferon, interferon and cycloferon. Symptomatic and pathogenetic treatment according to the prevailing symptoms.

Complications of foot and mouth disease

The prognosis for treatment is favorable and there are no specific complications as such, but in children, secondary aphthae can be localized in the gastrointestinal tract and cause symptoms of gastroenteritis. Secondary bacterial complications are often recorded at the site of cutaneous aphthae.

Prevention of foot and mouth disease

Vaccination of animals with an attenuated strain of the pathogen obtained through repeated passage and elimination of pathogenicity.
Disinfection;
Compliance with sanitary and hygienic rules when caring for sick animals.

Foot and mouth disease transmitted from person to person was not recorded. After an illness, immunity is formed, but the duration of its activity has not been established.

General practitioner Shabanova I.E.

The causative agent of the disease is a virus

The foot and mouth disease virus is transmitted from animal to animal and from animal to human. A sick person is a carrier of the virus, but cannot transmit the virus to another person. Due to the unformed immune system Children are more susceptible to the pangolin virus than adults.

The virus that causes foot-and-mouth disease is extremely pathogenic: when it enters the body, the virus not only resides in it, it necessarily causes disease. At the same time, the virus is quite dermatotropic - it likes to be localized on the skin, so if the disease occurs, it can be seen on the skin.

The causative agent of foot and mouth disease is quite resistant to low temperatures and drying. However, exposure to ultraviolet rays is harmful to it. High temperatures are also detrimental to foot-and-mouth disease: at a temperature of 60°C, the virus dies. Conventional disinfectants can also kill the pangolin virus; the virus is very sensitive to them.

An epidemic of foot and mouth disease is periodically observed in various animals. In animals, the disease manifests itself in the form of ulcers in the area of ​​various mucous membranes: nasopharynx, nasal cavity, mouth, tongue, and possible ulcers on the lips. Also, sores containing the virus can be seen on the animal’s skin: in the crevices between the hooves, on the udder of cows, near the horns, etc.

When animals start getting sick, the people who work with these animals are also likely to get sick. People who care for, slaughter, milk, and treat animals can become infected with foot-and-mouth disease virus from animals. by airborne droplets. Therefore, all people who work with artiodactyl animals must wear and change masks while working. A person can become infected with the virus even before they know that the animal is sick: incubation period(the period from the virus entering the body to the appearance of the first symptoms) in animals is 2-4 days.

The vaccine against foot and mouth disease was created only for animals, and it is constantly being improved. There is no such vaccine for people due to the short-term course of the disease and successful recovery.

Ways of transmission of the disease

You can become infected with the virus through the raw milk of sick animals and dairy products prepared from it. dairy products

Often artiodactyl animals may develop foot and mouth disease, a disease that can become a real epidemic among animals. A person becomes infected with the virus from an animal. There are several ways the virus can be transmitted from animals to humans.

1. Through raw milk of sick animals and dairy and fermented milk products prepared from it (sour cream, kefir, fermented baked milk, cottage cheese, cheese).
2. By airborne droplets for people who constantly work and come into contact with animals, if among the animals there are people with foot-and-mouth disease.
3. The virus can be transmitted to humans through objects that have been in contact with the secretions of a sick animal - buckets, bowls, rags used to wipe the animal, etc.
4. Sometimes a person can get sick by eating the meat of a sick animal, but this situation is possible if you eat raw meat or meat that is not completely thermally processed, as well as meat with blood.

Symptoms of the disease

The disease begins with a sharp rise in temperature, chills, as well as muscle pain and headaches.

Foot and mouth disease enters humans through scratches, microcracks and damage to the skin, mucous membranes of the mouth or nose. At the point where the virus enters the body, a primary lesion appears - a vesicle in which the virus multiplies and accumulates. The virus then enters the blood. It is at this stage of the disease that a person develops pronounced symptoms, one of them is intoxication. Then the virus from the blood again passes into the mucous membranes and onto the skin. It can be seen on the mucous membranes of the mouth and nose or on the skin of the feet and hands.

The most important indicator of foot and mouth disease is symptoms and a biological test on animals (isolation of the virus from blisters in humans and infection of laboratory animals with it). The incubation period in humans lasts from 2 to 4 days (sometimes it can reach 12 days).

1. The disease begins with sharp increase temperatures: up to 39-40°C.
2. Chills appear, followed by headaches and muscle pain.
3. Towards the end of the first or second day, a person feels a burning sensation in the oral cavity, and there is strong salivation.
4. The conjunctiva of the eyes begins to turn red, the person feels some pain when urinating, and diarrhea may occur.
5. Swelling of the mucous membranes of the cheeks, lips, tongue, and palate appears. After a few days, small bubbles can be seen on the swelling, which are filled clear liquid. After some more time, the bubbles change their color - the liquid in them becomes cloudy.
6. Bubbles on the swelling of the mucous membranes disappear, and erosions form in their place, which often merge and form a fairly large lesion.
7. Regional lymph nodes are enlarged; when palpating them, a person feels some pain.
8. A person's salivation increases (the amount of saliva produced can reach 2-4 liters).
9. Foot and mouth disease is characterized by blisters that are found between a person's fingers and toes, near the nails.

Foot and mouth disease in humans goes away within a week, but sometimes the disease can drag on for months (in case of weakened immunity). Foot and mouth disease is a disease that affects children more and is more severe in them than in adults. The main symptoms in children include gastrointestinal disorders, possible vomiting, nausea, and inflammation of the gastric mucosa.

Treatment of the disease

Treatment should begin with taking antipyretic drugs

Diagnosis of foot and mouth disease is carried out after the first symptoms of the disease appear in a person. Once the diagnosis is confirmed, the person begins treatment: for successful treatment apply means traditional medicine and traditional medicines. The mandatory combination of these two methods allows a person to quickly get rid of the disease and tolerate it easily. It is the combination of traditional and folk medicine methods that prevents the disease from developing and dragging on for months.

Treatment of foot and mouth disease begins with antipyretic drugs, namely drugs, because standard teas are not enough. Under no circumstances should you wipe a sick person with vinegar - he will receive additional skin burns.

All rashes must be covered with oxolinic, tebrofen or florenal ointment. These ointments will kill the virus and prevent it from spreading further throughout the body.

A sick person's meals should be divided: 5-6 times a day. In this case, food is taken in a liquid and semi-liquid state: it is quite difficult for people with swelling of the mouth, lips, tongue and cheeks to consume liquid food. At the same time, traditional medicine advises to avoid spicy food so that it does not injure the gastric mucosa.

Folk remedies

Calendula decoction can be used as a folk remedy.

• Treatment of foot and mouth disease with traditional medicine begins with rinsing the mouth with chamomile decoction. For this, 2 tsp. dry chamomile, pour a glass of boiling water, allow to cool to room temperature and rinse the mouth 3-5 times a day.
• Bubbles on the skin can be lubricated with low-fat sour cream. However, if the bubbles have opened and their contents have come out, then nothing can be lubricated. It is best to moisten a piece of bandage in warm water and wipe the opened bubble, and then apply a dry piece of bandage to that place. This is necessary so that erosion does not spread across the skin.
• As a folk remedy, you can also use calendula decoction: 1 tbsp. l. dry calendula inflorescences are poured with a glass of boiling water and left for an hour. A piece of gauze is soaked in the broth, squeezed out and gently wiped off any unopened bubbles. You can wipe not only the bubbles on the skin, but also on the lips and in the nasal cavity.
• Rinsing your mouth with warm water is another folk method fight against foot and mouth disease. In this case, the water temperature should reach 60°C, but not be hot. This rinsing should be done 4-5 times a day.
• Due to intoxication of the body, a person should drink plenty of fluids. Due to high temperature, a person loses not only fluid, but also salts, which are vital for the body. Be sure to drink salty drinks or mineral water. For a glass of warm boiled water you need to add 1/4 tsp. regular salt. You should drink at least 4 glasses of this solution per day to restore balance in the body. In total, a sick person needs to drink at least 2 liters of clean water per day.

Foot-and-mouth disease (Latin - Aphtae epizooticae; English - Foot-and-Mouth disease) is an acute, highly contagious viral disease of domestic and wild artiodactyl animals, characterized by fever and aphthous lesions of the oral mucosa, hairless areas of the scalp, udder, corolla , interclaw gap and accompanied by impaired movement; in young animals - damage to the myocardium and skeletal muscles (see color insert). Sometimes a person gets foot and mouth disease.

Historical background, distribution, degree of danger and damage. Foot and mouth disease has been known to mankind for more than 400 years. Animal disease accompanied by profuse salivation, were repeatedly noted in a number of European countries in the 17th-19th centuries.

The foot-and-mouth disease virus, the first of the causative agents of viral diseases in animals, was discovered in 1897 by German scientists Lefler and Frosch. At the beginning of the 20th century. French, German and English scientists established a multiplicity of pathogen types, which had a great practical significance in the development of diagnostic and disease prevention tools.

Foot and mouth disease is recorded in many countries around the world. According to the OIE, every year 55...70 countries become unfavorable for foot-and-mouth disease. Information about foot-and-mouth disease in animals in Russia began to appear in the literature from the middle of the 19th century. In the XIX-XX centuries. FMD in Russia was recorded periodically in the form of an epizootic, covering large areas of the country. Since 1989, Russia has been free from foot-and-mouth disease, but periodically the pathogen is introduced into our territory from disadvantaged, in particular neighboring, countries. Thanks to the developed strategy, the disease can be eliminated in the primary foci.

In modern conditions, people practically do not get sick with foot and mouth disease.

Foot and mouth disease can cause great economic damage even today. Thus, during an epidemic of foot-and-mouth disease in pigs in Taiwan in 1997, the total economic loss amounted to about 10 billion US dollars. At modern integration European countries, the emergence of foot-and-mouth disease in them led to serious economic and social problems. During the FMD type O epidemic in the UK in 2001, over 1000 FMD outbreaks occurred within 6 weeks and the total economic loss was more than US$20 billion.

The causative agent of the disease. The causative agent of foot-and-mouth disease is a very small RNA-containing virus belonging to the genus of rhinoviruses of the Picornaviridae family. The virus has a complex antigenic composition: there are 7 serological types (O, A, C, SAT-1, SAT-2, SAT-3, Asia-1). Each type has a certain number of options (subtypes): type A has 32 options, O - 13, C - 5, SAT-1 - 7, SAT-2 - 3, SAT-3 - 4, Asia-1 - 2. In the world type O causes the disease in 38% of cases, A - in 33%, C - in 26%. On the territory of our country during the years of the epizootic, mainly foot and mouth disease of types A (76.4%) and O (19.2%) was recorded. However, in recent years, foot and mouth disease type O has become prevalent, as in the rest of the world. The types and variants of the virus differ immunologically: each of them can cause disease in an animal that is immune to other types and variants of the virus.

The virus reproduces well in cell culture of epithelial tissues of susceptible animals with the manifestation of CPE. It is highly virulent: lymph from aphthae at a dilution of 1:106 causes foot-and-mouth disease in infected

Attractive animals. Passaging of the virus is carried out on laboratory animals (guinea pigs, mice, rabbits). In animals, the virus induces the formation of antibodies specific to each serotype of the pathogen. Therefore, serological tests are used to differentiate serotypes and variants of the foot-and-mouth disease virus.

The causative agent of foot and mouth disease is classified as resistant to chemical disinfectants (group 2). The virus is resistant to ether, chloroform, carbon tetrachloride, and is not inactivated by a 1% phenol solution, 75% ethyl alcohol, withstands the action of Lysol and toluene in concentrations that have a detrimental effect on a number of other viruses and bacteria. The resistance of the virus increases significantly if it is contained in the rejected walls of the aft. On mountain pastures it can persist until the next grazing season; in wastewater in the cold season it survives up to 103 days, in the summer - 21 days, in the fall - 49 days. The virus persists on animal fur for up to 50 days, on clothing - up to 100, indoors - up to 70, in feed - up to 30...150, soil - up to 40... 150, in fresh milk (4°C) - up to 15, in sausages - up to 56 days. In salted and smoked products - up to 50 days. In fast-frozen meat (below -20 °C), the virus can persist for years. In a 50% glycerol solution in phosphate buffer (pH 7.2) at 4.8 °C, the virus-containing material remains infective for 40 days. This preservative is used when sending materials to the laboratory.

The most effective when carrying out disinfection measures for foot and mouth disease are 1...2% hot solutions of sodium and potassium hydroxide, which have a detrimental effect on the foot and mouth disease virus in the first 10...30 minutes, 2% formalin - 10 minutes, Virkon C 1 : 200, 1% iodine, 4% hydrogen peroxide solution.

Epizootology. The highest contagiousness of the disease, long-term carriage of the virus in the body of animals and its long-term preservation in the external environment, wide range susceptible domestic and wild animals, the multiplicity of types and subtypes of the virus - all these factors ensure the stability of the pathogen, its preservation in nature and the reproduction of the epizootiological process (Table 5.1).

5.1. Basic epidemiological data for foot and mouth disease

A characteristic feature of foot and mouth disease is its almost absolute specificity for artiodactyls. Wild artiodactyls (buffalo, saigas, etc.) can act as a natural reservoir of various types of viruses.

The number and virulence of the virus are not the same in various stages illnesses and various types animals.

The spread of foot-and-mouth disease largely depends on economic and economic relations, methods of livestock farming, animal population density, degree of population migration, conditions of procurement, storage and processing of products and raw materials of animal origin. The risk of pathogen introduction associated with animal imports has also long been recognized.

The following factors can be considered an epidemiological feature of foot-and-mouth disease: multiple routes of transmission of the infectious agent and a very short incubation period, as a result of which the circulation of the virus among animals accelerates and new sources of the infectious agent quickly appear; a large number of naturally susceptible species of domestic and wild animals; release of a large amount of virus, highly resistant to various factors external environment; the presence of several immunological types and many variants of viruses.

Pathogenesis. Primary reproduction of the virus occurs in the mucous membrane of the nasopharynx, lymph nodes of the head, neck and tonsils 18 hours after infection. Primary aphthae are formed at the sites of virus penetration. From here, the virus enters the blood through the lymphatic tract and then into the organs of the lymphoid-macrophage system, where there are optimal conditions for its abundant accumulation and formation of a focus of infection. Clinically, this phase of the disease is manifested by an increase in body temperature, the rapid formation of secondary or generalized aphthae and exanthema on areas of the skin not covered with hair ( nasal speculum, nasal openings, udder skin, sometimes the scrotum and roots of the horn), on the mucous membranes (oral cavity, esophagus, rumen, vagina) and on the skin around the

Pyt (corolla, interhoof cleft, crumbs). Most often this occurs 48 hours after infection.

Possessing myotropic properties, the foot and mouth disease virus is also fixed in the fibers of the cardiac and skeletal muscles, causing various functional disorders heart and tissue defects.

With low virulence and a small infectious dose of the virus, as well as the resistance of the animal, the development of infection can stop or proceed latently. Latent infection is especially common in sheep.

Current and clinical manifestation. Clinical signs of the disease depend on the individual sensitivity of the animal to the foot-and-mouth disease virus, its physiological state and the degree of virulence of the pathogen. The most typical signs of the disease are expressed in adult large cattle. In other animals (lambs, piglets, calves) they may be less typical. Possibly benign and malignant manifestation foot and mouth disease

For foot and mouth disease in cattle, the incubation period averages 1...3 days, less often up to 21 days. The course of the disease is acute. With a benign course of foot and mouth disease, the animal’s appetite initially worsens, chewing gum slows down, and salivation increases. Then the body temperature rises to 40.5...41.5°C. Animals eat little or do not take food at all, they are depressed, they have a rapid pulse and breathing, lack of chewing cud, and their milk yield sharply decreases. During this period, the mucous membrane is dry, hot, hyperemic. On the 2...3rd day after the onset of fever on the mucous membrane of the oral cavity (on the upper and lower lip, toothless edge lower jaw), on the tongue, on the wings of the nose, sometimes on the nasal planum, aphthae (vesicles) appear, filled with first clear, then cloudy liquid. When the process generalizes, characteristic aphthous lesions form on the nipples of the udder, on the skin of the corolla, in the interhoof cleft, on the pulp of the hooves, and sometimes at the base of the horns. After 12...36 hours, the aphthae open, the lymph contained in them mixes with saliva and is released from the oral cavity; note profuse drooling, a kind of smacking, foamy mass in the corners of the mouth. In place of the burst aphthae, painful erosions with jagged edges form, healing in 6...8 days. If the process is complicated by a secondary infection, healing occurs in 2...3 weeks. When aphthae appear, the body temperature drops to normal. In complicated cases, recovery is slow. The udder is more often affected in lactating cows. Aphthae appear on the nipples various shapes and magnitude. Erosion forms at the site of the opened blisters, making it difficult to milk. The milk is slimy and has a bitter aftertaste. Sometimes patients experience mastitis, endometritis and diarrhea. Milk yield decreases by 20...75% and after recovery is not fully restored. In newborn calves, aphthae do not form; gastroenteritis is typical. The duration of the disease with a benign course is 8... 10 days, with complications up to 25 days. With a malignant course, calves often die from foot and mouth disease. The disease initially occurs with typical signs. On the 7...10th day after the onset of the disease, the animal’s condition worsens sharply; note a secondary increase in body temperature, depression, rapid pulse- up to 120... 140 beats per minute, muscle tremors and seizures. The animal dies from cardiac paralysis.

In sheep, the incubation period is 1...6 days. The limbs are mainly affected. Redness, swelling and soreness appear on the skin of the corolla and in the interhoof crevices. Later on these

In some places, aphthae appear, which rupture, and in their place, foci of erosion form, which leads to lameness. When ewes become ill, lactation often stops; aphthae or small pockets of erosion are found on the udder. Aphthae rarely form in the oral cavity, but salivation does not occur. When foot and mouth disease appears during the lambing period, there is a massive mortality of newborn lambs from damage to the heart muscle. Often foot and mouth disease in sheep occurs in a latent form, without severe severe symptoms diseases.

In goats, the incubation period is 2...8 days. The disease proceeds more typically, often with the formation of small aphthae and foci of erosion; the mucous membrane of the oral cavity, the skin of the extremities and, less often, the udder are affected. Drooling is mild. When the limbs are affected, goats become severely lame. Foci of erosion heal slowly, general state animals deteriorates, depression sets in, appetite disappears, body temperature rises to 41 ° C and higher. Sick animals lie down more often. Coming from the mouth bad smell, diarrhea or constipation are observed. With a benign course, animals recover in 10...14 days. The kids are seriously ill, and there is a high mortality rate.

For foot and mouth disease in pigs, the incubation period lasts 2... 14 days. FMD occurs relatively easily in gilts. In adult pigs, especially boars and lactating sows, the disease is more severe. Suckling piglets become acutely and seriously ill. In pigs with foot and mouth disease, depression and loss of appetite are observed, and during the period of aphthae formation, the temperature rises to 41...42 "C.

The most common clinical sign of foot and mouth disease in pigs are aphthae and erosions on the corolla, hoof pulp, and interhoof cleft, which is accompanied by lameness and often collapsed hooves. Aphthae and erosions also form on the snout, and in suckling sows - on the udder. When the udder is damaged, sows often stop lactation, and many of the suckling piglets underneath them die. The oral mucosa is rarely affected. Foot and mouth disease in pigs develops quickly, clinical symptoms in a sick animal may disappear within 10 days, but with a large concentration of livestock, the spread of infection can be prolonged.

In suckling piglets, foot and mouth disease is characterized by the appearance of many aphthae, which develop not only on the mucous membrane of the oral cavity and snout, but also on the skin over almost the entire surface of the body. Often foot and mouth disease in young animals occurs without the formation of aphthae in the form of a general septic process; sometimes signs of acute gastroenteritis are observed; in most cases, piglets die in the first 2-3 days of illness.

Foot and mouth disease is also diagnosed in wild animals. Repeated mass diseases of foot-and-mouth disease have been described in saigas in Kazakhstan, as well as in Russia in the Lower Volga region and the North Caucasus. Foot-and-mouth disease has been reported in reindeer, gazelle, roe deer, wild goats, elk, deer, argali, wild boar, bears, etc.

Cases of foot and mouth disease were also noted in zoos among reindeer and sika deer, fallow deer, ibex, aurochs, gayal, wapiti, European mouflon, deer, yaks, buffalo, bison, bison, bison and other wild animals. In a number of cases, a malignant course of foot and mouth disease was recorded in them, accompanied by death, especially in young animals. Wild animals can remain asymptomatic carriers of the pathogen and be a source of its spread in natural conditions.

Pathological signs. When autopsying the corpses of dead animals, exanthema, aphthae and erosions characteristic of foot-and-mouth disease are found on the mucous membrane of the oral cavity, often the esophagus and proventriculus. In young farm animals of different species (calves, piglets, lambs), changes are characterized by hemorrhagic inflammation mucous membrane of the gastrointestinal tract, characteristic of acute gastroenteritis. In the malignant course of foot and mouth disease, the main changes are noted in the heart muscle. The myocardium is flabby, has a gray-dirty-yellowish, whitish color or striping (“tiger heart”); there are hemorrhages under the epi- and endocardium. The same changes are found in skeletal muscles. The liver is enlarged and degenerated.

Diagnosis and differential diagnosis. Timely diagnosis foot-and-mouth disease, determining the type and variant of the virus are important for the rapid localization and elimination of infection during the first outbreak of the disease, as well as preventing its further spread.

The diagnosis is made on the basis of epidemiological data, clinical signs disease, pathological changes and results laboratory research.

From epizootological data, the following are taken into account during diagnosis: 1) the range of susceptible animals - artiodactyls; 2) the degree of spread and speed of coverage - within 10... 15 days, most of the animals on the farm fall ill; 3) economic ties of the enterprise with farms unfavorable for foot-and-mouth disease in a given area, region, republic; 4) absence expressed connection diseases with seasonality and natural and climatic conditions; 5) data on previous vaccination and exposure of animals to foot and mouth disease.

Suspicion of foot and mouth disease is caused by any disease of susceptible animals, characterized by the appearance of a vesicular rash in the oral cavity, on the limbs and udder, increased salivation, smacking, difficulty in eating and chewing food, and upon examination of the oral cavity - the detection of aphthae and erosions. In addition, they pay attention to lameness, aphthae on the corolla and in the interhoof gap, sometimes the collapse of the horny shoe, aphthae on the nipples and the pain of the latter during milking and sucking (in this case, the protective reflex is strongly expressed). During the period of threat of foot and mouth disease, it is necessary to pay attention to the depressed state of the animal, decreased appetite and milk secretion, increased body temperature, etc.

Laboratory diagnosis of foot and mouth disease is presented in Figure 5.1.

Material to be tested: from cattle, the walls of mature, unruptured aphthae are taken from the tongue, from pigs - from the snout or udder, from small cattle - from the toothless edge of the lower jaw, the skin of the inter-hoof cleft or corolla; blood at the time of temperature reaction; from the corpses of young animals - lymph nodes of the head and retropharyngeal ring, pancreas, heart muscle. To test for virus carriage, scrapings are taken with a probe from the mucous membrane of the pharynx or esophagus.

Collection, preservation and shipment of materials for laboratory diagnosis of foot and mouth disease are carried out in accordance with current instructions and methodological instructions.

ELISA and PCR are currently widely used as express diagnostic methods.

Rice. 5.1. FMD virus isolation and identification scheme

Based on the results of laboratory tests, the farm is considered unfavorable for foot-and-mouth disease in any of the following cases: 1) positive results(with a score of at least three crosses) in the RSC when examining pathological material and determining the type of virus, taking into account clinical and epidemiological data; 2) development in guinea pigs (24–72 hours after the introduction of the material) of primary aphthae, and then a generalized process, accompanied by the appearance of secondary aphthae on the tongue and plantar surface of the front paws; 3) development of paresis and paralysis in three pups (4...5 days of age) after infection with pathogenic material, and then their death during normal physiological state three control animals.

Retrospective diagnostics in order to determine the type and variant of the foot-and-mouth disease virus that caused the disease in the past is based on the identification of antibodies in RDP, RID, NRIF, and the seroprotection reaction in RN mice in cell culture.

In the differential diagnosis of foot and mouth disease, it is necessary to exclude viral vesicular stomatitis, viral diarrhea, malignant catarrhal fever, rinderpest, smallpox, necrobacteriosis, infectious rhinotracheitis, contagious ecthyma, bluetongue of sheep, vesicular exanthema of pigs, stomatitis, traumatic diseases, poisoning with certain substances. Diseases with vesicular syndrome exclude bioassay (Table 5.2).

5.2. Differential diagnosis diseases of pigs with vesicular syndrome

Immunity, specific prevention. Animals that have recovered from the disease acquire immunity to the type and variant of the virus that caused the disease. The duration of immunity in cattle is 8...12 months, in pigs 8...10, in sheep about 18 months. Colostral immunity is well expressed, but calves that have not received colostrum do not have serum antibodies. In calves, passive protection lasts up to 3 months.

For immunoprophylaxis of foot-and-mouth disease and the fight against epizootics in disadvantaged and directly threatened farms, they have been developed and used inactivated vaccines With for preventive purposes, as well as for forced processing of animals in areas unfavorable and threatened by foot-and-mouth disease (Table 5.3).

Prevention. The multiplicity of FMD pathogen types, the varied transmission mechanisms and the wide range of susceptible animals represent the main challenges in FMD control.

The system of anti-foot and mouth disease measures in our country is based on scientifically based forecasting of the epizootic situation and provides for a zonal principle of their implementation. The priority in the system is general veterinary and sanitary measures to prevent the introduction of foot-and-mouth disease virus, and in areas of permanent threat and in zones high degree risk of the occurrence and spread of foot and mouth disease, along with them, vaccine prevention is provided.

Treatment. Treatment is carried out only in countries where foot and mouth disease is widespread. If a primary outbreak of foot-and-mouth disease occurs on the territory of Russia, treatment of sick animals is not carried out.

IN initial stage serotherapy using hyperimmune serum or convalescent blood (serum) is effective. To reduce morbidity and mortality among animals and prevent the development of complications, patients are treated with improved living conditions, frequent watering, prescribed dietary feed (grass, flour mash), symptomatic treatment in the form of disinfectant solutions or ointments for treating affected mucous membranes and skin. Glucose is administered intravenously, antibiotics and cardiac medications are used.

Control measures. When foot-and-mouth disease occurs, measures to eliminate it are determined by the epizootic situation, geographical conditions, method of livestock farming, level of development of the country, etc. Taking this into account, measures to combat foot-and-mouth disease in different countries can be divided into four areas.

1. A radical method of combating foot-and-mouth disease (the so-called stamping out) consists of the immediate slaughter of all patients suspected of having the disease and suspected of infecting susceptible animals and refusing vaccination. This method used in developed, prosperous countries at the initial appearance of the disease. This method can completely eliminate foot and mouth disease in the primary focus.

2. Refusal of preventive immunization of animals, and in the event of foot and mouth disease, slaughter (destruction) of animals in the outbreak and carrying out forced vaccination around the source of infection.

3. Systematic preventive immunization of susceptible animals in endangered areas. If foot and mouth disease occurs, slaughter (destruction) of patients and conduct ring vaccination around the source of infection (successfully used in our country).

4. Complex method fight against foot and mouth disease, consists in combining the method of slaughtering sick and suspected animals with active immunization of susceptible livestock while simultaneously

5.3. Characteristics of vaccines used for preventive and compulsory vaccination of farm animals against foot and mouth disease

Rice. 5.2. Measures to eliminate foot and mouth disease

Carrying out sanitary and quarantine measures. The complex method is used in areas previously unfavorable for foot-and-mouth disease, in border zones, especially when there is a threat of introduction of foot-and-mouth disease, in the areas of institutes and enterprises involved in the production of anti-foot-and-mouth disease biological products. In the event of foot-and-mouth disease, sick and suspected animals are isolated or killed. The affected area is quarantined, and all animals in the endangered area are immunized. This method should be considered the most effective, since activities are aimed at all links of the epizootic chain.

Measures to eliminate foot and mouth disease in a disadvantaged area are presented in Figure 5.2.

When organizing events, one should distinguish between an epizootic focus, an unfavorable area and an area endangered by foot-and-mouth disease.

Quarantine is lifted 21 days after the last sick animal at a given point has recovered.

The restrictions after the quarantine is lifted are quite strict. Prohibited: export and import of animals for 1 year after the lifting of quarantine; use of pastures and cattle trails for 1 year. Vaccinated animals can be administered 21 days after vaccination. Within 3 months after the quarantine is lifted, recovered animals can be sent for slaughter only to a meat processing plant in the given region. Animals that are not sick but vaccinated can be sent for slaughter 21 days after vaccination. Animal products and plant origin that have had contact with the foot-and-mouth disease virus are used on site.

Measures to protect people from foot and mouth disease. Foot and mouth disease occurs very rarely in humans. Infection occurs when caring for sick animals; people with weakened bodies or children often get sick when consuming raw milk from sick cows. The prognosis is often favorable. Recovery occurs in 10...15 days.

Personal prevention in disadvantaged areas comes down to prohibiting consumption raw meat, milk and dairy products. Boiling or pasteurization of milk is required. Caution is required when caring for sick animals (washing and disinfecting hands, workwear - aprons, gloves, boots).

Test questions and assignments. 1. What are the antigenic differences of the foot-and-mouth disease pathogen that must be taken into account in anti-foot-and-mouth disease work? 2. What are the features of the epizootic process for foot and mouth disease? 3. What are the sources and reservoirs of the foot and mouth disease virus, the methods of its transmission and the ways of spreading the disease? 4. How is foot and mouth disease diagnosed and from what diseases should it be differentiated? 5. List a set of general and specific measures for the prevention and elimination of foot and mouth disease in animals of different species. 6. What anti-foot-and-mouth disease measures are carried out in the epizootic focus, disadvantaged area and threatened zone?

History and distribution. The clinical picture of the disease in humans was described in the 18th century. In 1897-1898 Leffler and Frosch proved the viral etiology of foot and mouth disease. Epizootics of foot-and-mouth disease occur everywhere, until the beginning of the 21st century; people rarely get sick.

Epidemiology of foot and mouth disease

The reservoir of infection is two-hoofed animals, mainly cattle. Goats, sheep, and pigs get sick less often. Human infection usually occurs by consuming raw milk from sick animals, but it can also be transmitted through direct contact with sick animals. Foot and mouth disease cannot be transmitted to humans. Children get sick more often, since milk is one of the main foodstuffs for them. People, mainly children, become infected by consuming raw milk and undisinfected dairy products. Diseases among adults are mainly of an occupational nature.

Causes of foot and mouth disease

The causative agent is an aphthovirus of the picornavirus family, contains RNA, is resistant to environment, is thermolabile, has seven serovars.

The causative agent is a virus 8-20 mm in size. There are 3 known serotypes of the virus (A, B and C). Resistant to freezing and drying. Quickly dies when heated, under the influence of ultraviolet irradiation, disinfectants. The portal of infection is the oral mucosa, where primary aphthae occurs. Then the virus enters the blood. Possessing pronounced epitheliotropy, the virus is fixed in the mucous membranes, forming secondary aphthae, and in the skin of the hands.

The pathogen passes through the oral mucosa and damaged skin (microtraumas). Primary replication of the virus occurs at the site of its introduction, where the primary affect (primary aphtha) is formed, then viremia develops, which is accompanied by intoxication and marks the onset of the disease.

Pathomorphology has been little studied. In the biotypes of the affected areas of the mucous membranes and skin, focal necrosis of the epithelium is detected. Fatalities may be associated with secondary infection, dehydration and severe specific lesions internal organs, in particular myocarditis.

Symptoms and signs of foot and mouth disease

Three forms:

• cutaneous;
• mucous;
• mucocutaneous.

The beginning is acute. Stomatitis, burning in the mouth, drooling, pain when urinating and swallowing develop. Aphthae appear on the mucous membranes of the lips, palate, cheeks, pharynx, and nose. The bubbles burst and erosions appear.

The incubation period lasts from 2 to 15 days. After 1-2 days, patients feel dryness and burning in the mouth, sometimes pain when urinating. Upon examination, against the background of edematous, hyperemic mucous membrane, small bubbles with transparent contents are visible. They are localized on the tongue, mucous membrane of the lips, tongue, soft and hard palate. The contents of the bubbles quickly become cloudy, and after 1-2 days they open, and erosions - aphthae - form. Their appearance is accompanied by intense salivation. Due to the severe pain of aphthae, patients cannot eat. The submandibular lymph nodes enlarge and become painful. Healing of aphthae occurs in 3-5 days. During this time, body temperature normalizes. Rashes are also possible on the mucous membranes of the nose, pharynx, esophagus, urethra, vagina, conjunctiva of the eyes, and skin around the mouth. In children early age Diarrhea and vomiting are common. A protracted course of the disease with repeated rashes is possible. Leukopenia and eosinophilia are detected in the blood.

Patients experience weakness, malaise, headache, their appetite decreases and moderate muscle soreness occurs.

When contracting foot and mouth disease, young children become capricious and refuse to eat. Already in the first hours from the onset of the disease, sensations of pain and burning in the mouth become characteristic, which is associated with the formation of blisters - aphthae - on the oral mucosa. Chewing hard food is especially painful. When examining the oral mucosa, one notices that elliptical vesicles form on it - aphthae, filled with a clear liquid. The number of these bubbles varies individually, but in some patients they can dot the mucous membrane of the cheeks and lips, spreading to the tip of the tongue. There is marked hyperemia and swelling of the mucous membranes of the cheeks, lips and tip of the tongue. Repeated rashes are possible.

A very characteristic symptom of foot and mouth disease is profuse salivation, due to which saliva can flow out of the patient’s mouth almost without interruption in a thin stream and drops. Subsequently, the aphthae ulcerate, and due to the formation of small ulcers in places where there were aphthae, the patient experiences such severe pain that eating becomes extremely difficult and the patient has to be fed through a tube.

Possible formation of aphthae on the mucous membrane urethra, which causes severe pain when urinating. Aphthae also form at the nail folds on the fingers. In later periods of the disease, fingernails are affected.

The blood picture is characterized by moderate eosinophilia and leukopenia. The febrile period is 3-4 days. Sometimes there is a secondary, coccal infection that penetrates through ulcers in the oral cavity. The diagnosis is made on the basis of the clinical picture of the disease, taking into account epidemiological and epizootological data.

Complications of foot and mouth disease

Complications are most often caused by the addition of a secondary bacterial infection. In early childhood, hypersalivation, vomiting and diarrhea can lead to severe dehydration.

Complications:

• pneumonia;
• sepsis;
• myocarditis;
• meningitis;

Diagnosis of foot and mouth disease

It is necessary to differentiate from aphthous stomatitis of other etiologies. For laboratory confirmation diagnosis, you can infect guinea pigs by rubbing the test material into the scarified skin of their paw pads. The complement fixation reaction is also used specific antigen. Positive reaction becomes from the 10-12th day of illness.

It is possible to isolate a virus culture from the contents of vesicles, saliva, blood, and feces.

Differential diagnosis is carried out with aphthous stomatitis, herpetic stomatitis, herpangina, toxic and fungal stomatitis, chicken pox, pemphigus, Behcet's syndrome.

Diagnosis is carried out based on:

• passport data;
• epizootic situation;
• epidemiological history (place of residence, contacts with animals, their raw materials);
• complaints;
• clinical data;
• laboratory data:
• serological studies: RSK, RNGA, RN, RIGA;

Differential diagnosis is carried out with vesicular, aphthous stomatitis, exudative erythema, pemphigus, chickenpox, diseases caused by the Coxsackie virus, oral mycosis, herpes, Behcet's disease, herpes zoster, enteroviral diseases.

Treatment and prevention of foot and mouth disease

A semi-liquid diet is prescribed. Apply antiviral ointments - oxolinic ointment, florenal, tetrabromotetrahydroxydiphenyl (tebrofen ointment), heliomycin, interferon alpha-2. According to indications, detoxification and dehydration are carried out.

Oral care (rinsing with a solution of potassium permanganate, 3% solution of hydrogen peroxide, lubricating the aft with a 5% solution of silver nitrate). Symptomatic therapy. Antibiotics are ineffective. It is used to extinguish ulcers in the oral cavity by applying a tampon soaked in a 1% solution of silver nitrate to them for 2 minutes. For symptoms of secondary infection, use intramuscular injections penicillin in a dose of 1,000,000 units for an adult 2 times a day.

Prevention. Identification of animals with foot-and-mouth disease, followed by their quarantine, prohibition of consuming milk from cows infected with foot-and-mouth disease. Mandatory pasteurization or boiling of milk in all cases, regardless of the spread of foot-and-mouth disease in the area. Health education should be used whenever cases of foot-and-mouth disease occur in animals. Personnel working with animals use special clothing; in endemic areas, milk is consumed only in boiled form.

– acute infectious disease viral etiology, characterized by vesicular-erosive damage to the integumentary tissues (mainly the mucous membranes of the mouth and the skin of the extremities), accompanied by intoxication syndrome. FMD infection occurs from livestock and wild animals mainly through contact, but the food route is also possible. The clinical picture consists of acute conjunctivitis, common aphthous stomatitis, general infectious symptoms and damage to the skin around the mouth, on the wings of the nose, in the spaces between the fingers.

Diagnosis of foot and mouth disease

The pathogen is isolated from scrapings from erosions, saliva, feces, but in large quantities clinical practice Virological diagnostic methods are not used due to their complexity. Serological diagnosis of foot and mouth disease is carried out using HCR and RNGA in paired sera (sampling of material with an interval of 7 days). Sometimes a bioassay is performed on guinea pigs (the patient’s aphthae discharge is rubbed into the animal’s paw pads).

Treatment of foot and mouth disease

Treatment of foot and mouth disease is carried out in a hospital, the main therapeutic measures are aimed at caring for the oral cavity, local treatment, symptomatic relief. For a while pronounced lesions In the oral cavity, patients eat semi-liquid, easily digestible food of moderate temperature that does not contain irritating components. If necessary (extensive lesions), nutrition is provided through a tube or parenterally.

Ointments (oxolinic, florenal, interferon) and physiotherapeutic techniques (ultraviolet and laser irradiation) are used locally. Symptomatic remedies(painkillers, antipyretics, cardiovascular and desensitizing drugs) are prescribed according to indications. If necessary, detoxification measures are carried out. For general strengthening purposes, vitamins and adaptogens are prescribed.

The prognosis for foot and mouth disease is usually favorable; in the vast majority of cases, the disease ends in recovery without leaving behind pathological consequences. Severe foot and mouth disease in young children has a serious prognosis, in some cases resulting in death.

Prevention of foot and mouth disease

The basis of prevention is veterinary monitoring of the health of farm animals, timely routine vaccination (produced with inactivated foot-and-mouth vaccines), and quarantine measures for sick animals. In addition, sanitary and hygienic control is carried out over the health and working conditions of workers at agricultural enterprises.

Individual prevention consists of observing personal hygiene measures when working with livestock, animal raw materials, and protecting against injury to the skin. Among other things, it is necessary to consume dairy and meat products, having undergone the necessary processing, in particular, precautions are important when feeding children. People are not immunized.