African swine fever: symptoms and pathogen. African swine fever: symptoms, quarantine regime, prevention and control of the disease (120 photos and videos) African swine disease

African swine fever (lat. Pestis africana suum), African fever, East African plague, Montgomery's disease is a highly contagious viral disease of pigs, characterized by fever, cyanosis of the skin (cyanotic coloration) and extensive hemorrhages (accumulation of blood that has poured out of blood vessels) in the internal organs . It belongs to the list A (especially dangerous) according to the International Classification of Contagious Animal Diseases.

First recorded in 1903 in South Africa.

African swine fever virus is a DNA-containing virus of the Asfarviridae family; the size of the virion (viral particle) is 175‑215 nm (nanometer - a billionth of a meter). Several seroimmuno- and genotypes of the African swine fever virus have been established. It is found in the blood, lymph, internal organs, secrets and excretions of sick animals. The virus is resistant to drying and decay; at 60°C it is inactivated within 10 minutes.

The incubation period of the disease depends on the amount of the virus that has entered the body, the condition of the animal, the severity of the course and can last from two to six days. The course is divided into fulminant, acute, subacute and less often chronic. With a lightning current, animals die without any signs; in acute - in animals, the body temperature rises to 40.5-42.0 ° C, shortness of breath, cough, vomiting attacks, paresis and paralysis of the hind limbs appear. There are serous or mucopurulent discharge from the nose and eyes, sometimes diarrhea with blood, more often constipation. Leukopenia is noted in the blood (the number of leukocytes decreases to 50‑60%). Sick animals lie more, buried in the litter, sluggishly rise, move and quickly get tired. Weakness of the hind limbs, unsteady gait, the head is lowered, the tail is untwisted, thirst is increased. On the skin in the area of ​​the inner surface of the thighs, on the abdomen, neck, at the base of the ears, red-violet spots are noticeable, they do not turn pale when pressed (pronounced cyanosis of the skin). Pustules (abscesses) may appear on tender areas of the skin, in place of which scabs and ulcers form.

Numerous hemorrhages are found in the skin, mucous membranes and serous membranes. The lymph nodes of the internal organs are enlarged, look like a blood clot or hematoma. The internal organs, especially the spleen, are enlarged, with multiple hemorrhages.

The diagnosis is made on the basis of epizootological, clinical, pathoanatomical data, laboratory tests and bioassays.

In the event of a focus of infection, the total destruction of a sick pig population by a bloodless method is practiced, as well as the elimination of all pigs in the focus and a radius of 20 km from it. Sick and in contact with sick pigs are to be slaughtered, followed by incineration of corpses. Manure, leftover feed and low-value care items are also subject to incineration. The ashes are buried in pits, mixing it with lime. The premises and territories of farms are disinfected with a hot 3% solution of sodium hydroxide, 2% formaldehyde solution.

A quarantine is imposed on a dysfunctional farm, which is removed after 6 months from the date of slaughter of pigs, and breeding of pigs in a dysfunctional point is allowed no earlier than a year after the removal of quarantine.

Owners of private farms in which there are pigs must follow a number of rules, the implementation of which will preserve the health of animals and avoid economic losses:

Provide livestock of pigs for vaccinations carried out by the veterinary service (against classical swine fever, erysipelas);
- keep the livestock only closed, do not allow the free range of pigs in the territory of settlements, especially in the forest zone;
- every ten days to treat pigs and the room for their maintenance from blood-sucking insects (ticks, lice, fleas), constantly fight rodents;
- do not import pigs without the consent of the State Veterinary Service;
- do not use non-decontaminated feed of animal origin, especially slaughterhouse waste in the diets of pigs;
- limit ties with disadvantaged territories;
- immediately report all cases of disease in pigs to the state veterinary institutions in the service areas.

African swine fever (ASF) is a very dangerous and incurable infectious disease. The fatal outcome is almost one hundred percent, all animals are affected, regardless of age and the method of penetration of the virus into the body. It is important to know how dangerous African swine fever is to humans and its symptoms in order to prevent the massive spread of the disease.

The first information about the virus appeared relatively recently, in the first decade of the last century. Then the famous researcher R. Montgomery was in East Africa, where he registered a dangerous virus with a fatal outcome, so the disease is sometimes called by his name. Over time, the disease spread throughout the African continent, was introduced to Europe, then to America, and appeared later on the territory of the Russian Federation.

Carriers of the virus can be both animals that have been ill and recently ill (the pathogen can live in their body for about two years), excretion occurs with saliva, during urination, with blood or feces.

To understand how dangerous ASF is, you need to talk about possible ways of infection. There are several of them:

The symptoms and manifestations make African swine fever almost indistinguishable from classical swine fever. An incubation period of at least two days, but not more than two weeks, depends on a number of symptoms. This significantly complicates the correct diagnosis. The disease can be acute, subacute, hyperacute, chronic and asymptomatic. If ASF is acute, the animal dies about seven days after infection, hyperacute - a day or three, subacute - after two to three weeks. If during this time the death did not occur, most likely a chronic form develops, and the animal will die after complete exhaustion of the body.
It is important to know that African plague can affect not only domestic but also wild adult pigs or piglets, regardless of age, sex and breed. The disease manifests itself in different periods of the year. Long-term studies allow us to conclude that on the European continent most outbreaks of infection appear in winter and spring periods.
The final diagnosis is obtained after complex laboratory studies are completed.

Blood samples are obtained from infected animals, parts of internal organs (spleen) are obtained from dead pigs.

Blood is taken from animals that have been ill for a long time, as well as from those that have been in direct contact with sick animals of different ages.
In many cases, African plague is acute. During this time you can see:

The virus can mutate, the symptoms change, so not all, but only some of the alleged symptoms can manifest themselves in a particular territory.

Symptoms of African plague in humans

There are no vaccines or drugs that can be used to treat animals. Almost all sick pigs die.
If we talk about the danger of African swine fever for people, then it is absent. Meat products can be used and will be completely suitable for consumption, there is a long-term full and high-quality heat treatment (boiling, frying). It is necessary to take into account the fact that after smoking the virus will not be destroyed. When a person eats the meat of such a pig, nothing will threaten his life, because the disease is not transmitted to people from sick animals. But the veterinary service, in any case, after the establishment of the African plague virus, will introduce quarantine in a 20-kilometer zone, and will deal with the destruction of the entire pig population in this territory in order to prevent the spread of ASF. A person can also become a distributor of a dangerous disease. Let's take one simple example. The owner slaughtered one of the pigs he kept without even knowing it was infected. When this meat is eaten, the virus can spread to other animals. It is known that the unused residue of the pig breeder is put in a separate container, then thrown somewhere, most often as a feed for the remaining animals. So the disease will spread, and a person after eating meat products will become a distributor of the virus, without knowing it.

African swine fever is also called Montgomery's disease. It was first recorded at the beginning of the 20th century in South Africa. After that, in a fairly short period of time, she "moved" to Spain, Portugal, America, Central and Eastern Europe, Asia, and cases of swine diseases in Russia and Ukraine became more frequent. Initially, only wild boars were sick with it, but over time, it began to threaten ordinary domestic pigs as well.

What is African swine fever?

African swine fever (ASF) is an infectious disease that causes a number of very serious life-threatening symptoms in pigs. When examining the internal organs of diseased animals, many foci of hemorrhage are found, some organs are greatly enlarged, others swell.

The causative agent of the disease is the Asfivirus virus and this is what distinguishes the disease from simple swine fever, which is caused by the Pestivirus virus. At the moment, several genotypes and seroimmunotypes of the virus are known, each of which has, in fact, minor differences.

The genome of the African plague is very strong, it can survive at very low and high temperatures, drying, high acidity, rotting, freezing. And with all this, it remains active.

In pork meat, this virus can live up to several months, and is transmitted if it is not thoroughly cooked. But experts and doctors assure that ASF is harmless to humans if the meat is well fried or boiled at a temperature of 70 degrees Celsius and above before eating.

African swine fever is not dangerous to humans.

How is the virus transmitted?

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African swine fever is transmitted through the skin, oral cavity by direct contact with an infected individual. It is for this reason that the disease always reaches a large scale. Almost all individuals in the stall die if they live together and among them there is at least one infected pig.

Also, the virus can enter the body of a pig through the bites of insects that carry it (lice, ticks, zoophilous flies). The disease is also carried by rodents, birds, and even people who have contact with infected pigs. So healthy individuals in the stall do not provide 100% certainty that the disease will never appear.

The disease can “come” to the farm with poor-quality feed. African swine fever lives quietly in spoiled food waste, which is usually fed to pigs. Walking pigs in places where the influence of the virus was previously noticed is not recommended, since it can also live in the ground.

The lesion can occur regardless of the sex, breed or age of the pig. So all the animals that live together are at risk.

The main symptoms of the disease

The incubation period of the virus is 5-15 days. But in real life, it can be delayed for 1-2 weeks. It all depends not only on the virus itself, but also on how, where the pig was infected, its immune system and the amount of virions that entered its body. There are hyperacute, acute, subacute and chronic forms of African swine fever.

• Hyperacute illness develops instantly, and death occurs suddenly. In this case, the breeder may not be aware of the disease, and only then find out about the causes of death of the animal. This form has no symptoms.
• The acute form develops up to a week. It proceeds with high temperature (40.5-45 degrees), weakness, shortness of breath, lethargy, paresis of the limbs, purulent discharge from the nose, eyes, vomiting, diarrhea with blood. Bruises appear on the skin in the lower part of the neck, perineum, abdomen, ears. Perhaps the development of pneumonia, pregnant females lose babies. A few hours before death, the temperature drops dramatically, then the pig falls into a coma and dies.
• Subacute form lasts 15-20 days. There may be fever, lethargy. Death usually occurs as a result of heart failure.
• The chronic form is accompanied by secondary infections. Symptoms are periodic bouts of shortness of breath, fever. Wounds appear on the skin that do not heal even with enhanced treatment. The pig lags behind in development, looks very lethargic, does not eat up. Develops tendovaginitis, arthritis.

How to diagnose African plague?

As mentioned above, not all forms of this disease generally have symptoms, but in most cases the disease can be recognized. The first characteristic feature is cyanotic spots on the body of the animal. Immediately after their appearance, you need to contact the veterinary service and isolate the sick individual from any contact with other animals.

Veterinarians usually do tests (without them it is impossible to reliably identify the virus), conduct studies of the general herd and the sick individual, monitor their changes, and then make a diagnosis. In case of detection of ASF, the establishment of the causes of its occurrence and further development begins. African swine fever is distinguished from simple swine fever by differential diagnosis.

African swine fever treatment

There is currently no vaccine for African swine fever. Treating the disease is useless and even prohibited, given the rapid spread of the virus. This can only lead to new cases of infection and lead to a real epidemic.

It is worth noting that earlier the mortality rate from African swine fever was 100% and it usually proceeded in severe forms. But now cases of the chronic course of the disease have become more frequent.

The measures that are taken when a disease is detected can be called abruptly cardinal, but only this can stop the spread of the virus. The first thing to do is to destroy the entire herd of pigs that are on the farm, even those individuals that seem healthy. They are slaughtered in a bloodless way. After that, all pigs are burned along with items for their care, food, bedding in the barn. Ideally, the barn should also be burned, but this is not always possible.

The resulting ash is mixed with a large amount of lime and buried in the ground to a considerable depth. Pig farms and all nearby areas, buildings, are treated with a 3% hot solution of sodium hydroxide and 2% formaldehyde solution. For a whole year, the owners of the farm where the disease was discovered are prohibited from having animals.

All pets within 10 km of the disease outbreak are slaughtered and processed into canned food, and the region is quarantined. This is the only way African swine fever is currently contained.

What preventive measures are in place?

To protect the herd from African swine fever, breeders must take preventive measures.

Content:

African swine fever (ASF, East African distemper, African fever) is a highly contagious, acute viral disease. The disease is characterized by chills, fever, cyanosis of mucous membranes, skin, hemorrhagic lesions of internal organs. Despite the fact that many infectious diseases of pigs belong to the group of zooanthroposonoses, ASF does not pose a threat to human health, but at the same time, the contagious infection spreads almost at lightning speed and causes the death of the entire livestock, which causes great damage to farms. Mortality when pigs are infected with the African plague virus among piglets, adults is 100%.

Etiology, distribution

ASF was first diagnosed in pigs at the beginning of the 20th century in South Africa. The disease was classified as a natural focal exotic infection, which was often diagnosed in cultured and wild pig populations in Africa. Later, outbreaks of the disease were noted in Portugal, countries of Central and South America, Spain, and then in other countries of the world. In the Russian Federation and CIS countries, ASF was first diagnosed in 2008.

The causative agent of the infectious disease is a DNA-containing virus of the Asfarviridae family, the genus Asfivirus. There are two types of pathogen. namely: type A, B and subspecies C. African swine fever virus is resistant to high temperatures, various environmental factors. Does not lend itself to freezing, drying, rotting. Retains virulence in media at pH from 2 to 13. At a temperature of 5–7 degrees, it can last up to six to seven 6–7 years under favorable conditions. In animal corpses - from 15 days to 188 weeks. In faeces, the ASF virus persists for up to 160 days. Not resistant to high temperatures.

At 55–60 degrees, heat treatments under the influence of high temperatures, the virus is inactivated in 10–12 minutes.

The main feature of this infection is that the disease can manifest itself with different symptoms, depending on what type of virus the animal is infected with.

African distemper virus affects all age groups of domestic, wild pigs, regardless of gender, breed.

Important! It is worth noting that the ASF virus is almost impossible to completely destroy in nature. In addition, a preventive vaccine against the African plague virus has not been developed to date. There are no effective drugs that can be used in the fight against this disease.

Given the numerous statistical data, in the states of America and Europe, which are unfavorable for ASF, most often epizootic foci occur in winter, early spring, during the cold season.

How do pigs get infected?

The ASF virus enters the body of animals by aerogenic (airborne), alimentary route, through damaged mucous membranes, skin, conjunctiva. Infection is possible through inventory contaminated with pathogens, household items that were used in the care of sick pigs. poor-quality compound feed. Non-cooked food that is fed to animals can also cause infection with the ASF virus.

The source of the spread of a deadly infection is infected sick individuals, animals during the incubation period, sick pigs. Intermediate carriers of the disease can be called rodents, wild birds, blood-sucking insects.

Having penetrated the body of a piglet, an adult, the pathogen infects macrophages, which leads to the activation of transcription of free genes for the body's response. The ASF virus is localized in the endothelial cell structures of the blood, lymphatic vessels, in mononuclear phagocytes, myeloid, lymphoid tissues of the immune system.

The virus, as its amount increases in the body of sick animals, has a cytopathic effect on lymphocytes, endothelial cells. Over time, necrosis of the vascular walls develops, and the porosity of the vessels increases. The reproduction of the virus is accompanied by a cytopathic effect on lymphocytes, macrophages and endothelial cells.

Due to fibrinoid necrosis of the endothelium of blood vessels, the permeability of the walls of blood vessels increases sharply, venous and inflammatory hyperemia, thrombosis, and leukopenia appear.

On serous, on mucous membranes, skin, in parenchymal organs, after opening the corpses of animals, numerous hemorrhages are noticeable. Extensive necrosis of myeloid tissues is formed in the lymph nodes, bone marrow, and spleen. In sick pigs, the immune potential decreases, the immune defense weakens, and the body's natural resistance decreases. The disease is fatal in 100% of cases.

African plague symptoms

The intensity of the manifestation of clinical symptoms depends on the type of virus, the number of virions in the body of animals, the general physiological state, the reaction of the immune system, and the severity of the infection. The duration of the incubation period is from two 2 to seven 7 days.

Important! With swine fever, the symptoms can vary, and in any case, ASF ends with the death of infected animals.

African swine fever can occur superacutely, acutely, less often - chronically. As a rule, the first symptoms appear on the 2-5th day from the moment of infection. If distemper is diagnosed, in gilts, the symptoms of a fulminant course of the disease may be subtle. Sick individuals without any characteristic manifestations of symptoms die within 24–48 hours.

Signs of African swine fever:

• a sharp increase in temperature to 41.5–-42 degrees;
• an increase in regional lymph nodes;
• decreased appetite, refusal to feed;
• paresis, paralysis of the hind limbs;
• violation of digestive processes (constipation, diarrhea with blood impurities);
• anemia, cyanosis (cyanosis) of mucous membranes;
• difficult, shallow breathing, shortness of breath;
• subcutaneous edema, bruising in the subcutaneous tissue;
• sharp death of animals;
• pneumonia.

Sick animals look apathetic., literally weaken before our eyes. Pigs have a hard time getting up. Impaired coordination of movements. even after the slightest activity, infected animals quickly get tired. On palpation of the lymph nodes, severe pain is noted. Appetite is reduced or absent altogether.

A characteristic symptom that manifests itself in pigs infected with African swine fever is the appearance of dark purple spots with a red tint on the inner surface of the thigh, abdomen, neck, limbs, sides, back, patch, at the base of the ears.

Atypical form of ASF

The symptomatology varies in each individual infected individual, which is explained by the mutation of the virus. ASF can also occur in an atypical form, in which pigs suffer from profuse diarrhoea, a variable fever. On the ears, tail, limbs, patch, bruises are noticeable on the body. Animals weaken, lose weight, do not gain weight. The skin is covered with wrinkles, strongly compacted. Signs of conjunctivitis, gastroenteritis are clearly manifested. The infection ends in death, usually on the third day after the onset of the first symptoms. Mortality is 30-65%.

Atypical form of ASF is most often diagnosed in suckling piglets that were early weaned from the sow, in young animals that had contact with virus carriers or were infected with weakly virulent strains of the virus. At the same time, some piglets recover without treatment. The rest die or are lifelong virus carriers. The disease can be complicated by secondary infections.

Diagnostics, treatment

It is possible to establish the diagnosis of ASF only after a comprehensive diagnosis and laboratory tests. Veterinarians take into account the epizootological situation of African plague in the regions, conduct an examination of animals, differential diagnostics.

The diagnosis is also made on the basis of the results of pathoanatomical, serological studies. Blood samples are taken from pigs, fragments of internal organs (spleen, lymph nodes) are taken from corpses. The biomaterial should be examined as soon as possible in laboratories.

If African swine fever is diagnosed in pigs, unfortunately, no treatment methods have been developed to combat this disease. Effective veterinary preparations do not exist, so the main forces should be directed to preventive measures. When the first symptoms appear in large farms, animals are vaccinated. This technique will help save part of the uninfected livestock. The rest of the pigs are slaughtered.

Advice! If infection with the African plague virus is suspected, the pigs are poured 100–150 g of vodkat into the oral cavity. As a rule, sick individuals recover.

The corpses of sick animals, inventory, feed, manure are burned. The ash is mixed with lime and buried deep in the ground. In pigsties, a complete complex disinfection is carried out, using a hot 3% solution of sodium hydroxide, formaldehyde 2%. Quarantine is removed no earlier than six months later, and breeding of pigs can only be done after 12 months.

At a distance of 10–12 km from the unfavorable point, all pigs are killed. The meat is used for processing into canned meat.

ASF prevention

In order to prevent infection of pigs with African fever in pig farms, it is necessary to monitor the quality of feed, the state of the immune system of animals. It is necessary to carry out disinfection and deratization in the premises on a regular basis. New equipment that has not been disinfected must not be used.

Feed must be purchased in regions where ASF outbreaks have not been reported. Before feeding food of animal origin, it is necessary to carry out heat treatment.

Pigs should not be allowed to come into contact with other carnivores, inhabitants of neighboring farms, farms.

Acquire new individuals only with veterinary documents, keeping the pigs in quarantine for some time.

Slaughter of animals must be carried out in places specially designated for this purpose. At the slightest suspicion of infection with the African plague virus, pigs are isolated and placed in a separate room. Immediately you need to contact a veterinarian for a comprehensive diagnosis.

African swine fever (Pestis Africana suum, ASF) is a highly contagious disease characterized by fever, hemorrhagic diathesis, inflammatory, degenerative and necrotic changes in various organs and high mortality.

ASF became known only in the 20th century and was introduced as an independent nosological unit by R. Montgomery in 1921, although descriptions of the disease of pigs with symptoms of ASF in some countries of South Africa appeared in 1903-1905.

ETIOLOGY

The causative agent of the disease is a 20-sided cytoplasmic DNA-containing virus of the iridovirus family. The diameter of a mature virion is 175-215 nm. The virion has two capsid layers and an outer shell formed by budding through the cell membrane. It is a complex virus containing 28 structural polypeptides. In the body of a sick animal, the virus accumulates in all organs, secrets and excretions. The cultivation of the virus is possible in the culture of bone marrow and leukocyte cells.

The immunological multiplicity of virus types has been established.

The ASF virus is highly resistant. In the soil, it can last up to 180 days, on wood and bricks - 120-180 days;

in meat - 5-6 months, in bone marrow - 6-7 months, in pigsties after removal of diseased pigs - at least 3 weeks, at room temperature - from 2 to 18 months, at + 5 ° - up to 5 years. In defibrinated blood at +4°C, the virus remains active for 6 years, and in freeze-dried blood for 10 years.

The virus has increased resistance to formalin and alkalis, but is sensitive to acids and oxidizing agents. Therefore, for disinfection, it is advisable to use chlorine-containing preparations (chlorine, chloramine), carbolic, acetic or lactic acids (depending on the material to be disinfected).

epizootology

Domestic animals and wild pigs are susceptible to African plague, regardless of age. Domestic pigs and wild boars living in Europe are especially seriously ill. In wild African pigs (warthogs, bush and giant forest pigs), the disease is asymptomatic. The source of the causative agent of infection are sick and recovered pigs. Virus carrying in individual animals lasts up to two years or more. From the body of animals, the virus will stand out with all the secrets and excretions. Under natural conditions, infection easily occurs when sick pigs are kept together with healthy ones, mainly through the alimentary route. Infection is also possible by aerogenic means, through damaged skin and when bitten by infected ticks. The transmission factors of the ASF pathogen are various infected objects of the external environment (transport, care items, fodder, water, manure, etc.). Of particular danger are the products of slaughter of infected pigs and the food and slaughterhouse waste generated during their processing. Mechanical carriers of the virus can be people, as well as various domestic and wild animals, birds, rodents, insects (flies, lice).

The main reservoir of the pathogen in Africa is wild pigs, and in disadvantaged countries of Europe and America - domestic pigs and wild boars, in whose populations the virus circulates. The reservoir and carrier of the virus in countries that are stationary for African swine fever are 4 argas ticks of the genus Ornithodoros mubata - in Africa and Ornithodoros erraticus - in Europe, which become infected from infected animals. In the body of ticks, the virus can persist for many years and be transvariantly transmitted to offspring.

African swine fever is an epizootic. The rapid spread of the disease is explained by the high virulence of the virus, its significant resistance and the variety of ways of spread. The disease occurs at all times of the year, but it is most widely recorded in the summer-autumn period.

In zones that are stationary-unfavorable for ASF, there is a certain periodicity of mass outbreaks of the disease - in Africa after 2-4 years, in Europe - after 5-6 years. An important epizootological feature of African swine fever is high morbidity and mortality, reaching 98-100%.

Until the middle of the last century, the ASF nosorange was limited to the African continent and almost exclusively in countries located south of the equator, where outbreaks of infection regularly occurred due to the presence of natural foci, and the disease of domestic pigs occurred after contact with wild boars - virus carriers or when the herd was invaded by hematophagous. In 1957, the disease was brought from Angola to Portugal, in 1960 to Spain. These countries have remained endemic for ASF for over 30 years. Over the entire period, about 12,000, and in Spain, 8,540 disadvantaged points were registered in Portugal, where more than 2 million pigs were destroyed.

From the Iberian Peninsula, the disease spread to neighboring countries: France (1964; 1967; 1974), Belgium (1985), the Netherlands (1986), the infectious agent was first brought to Italy in 1967, again in 1978-1984. Subsequently, a secondary natural focus of the disease was formed on the island of Sardinia, which exists to this day, where obliterated forms of the disease predominate in animals (reservoir - wild pigs, carriers - argas ticks). African plague was also introduced on the other side of the Atlantic: to Cuba (1971; 1980), Brazil (1978-1979), Haiti (1978-1980), Dominican Republic (1978-1980). It should be noted that the emergence of primary foci of ASF in Europe and America is associated with the high activity of affected countries in Africa, especially in Mozambique, Angola, Nigeria, the Dominican Republic, South Africa, Tanzania, Zimbabwe, Rwanda, Namibia, Benin, Ethiopia, Kenya, Benin, Togo, etc.

ASF was registered in 1977 on the territory of the former USSR in the Odessa region and Moldova, where the entire population of pigs was destroyed not only in the outbreaks of the disease, but also in a 30-kilometer zone.

In recent years (2007-2009), a dramatic situation of the spread of the disease has developed in the countries of the Caucasus, where ASF was not previously recorded and was an exotic disease.

ASF is currently registered in 24 countries of the world, including Russia (Chechen Republic, Stavropol, Krasnodar Territory, North Ossetia).

The first cases of mass disease of pigs in Georgia were registered in March-April 2007, and the diagnosis with laboratory confirmation was established in June 2007.

According to experts from the Food and Agriculture Organization of the United Nations (FAO), the virus was brought to Georgia due to the improper use of waste from international ships carrying contaminated meat and meat products.

In 2007 alone, ASF in Georgia was registered in 52 out of 65 regions of the country (55 outbreaks), where more than 67,000 domestic pigs died. An exacerbation of the epizootic situation (an increase in morbidity, mortality and the number of unfavorable points) was also noted in 2008. The lethality of diseased pigs was 100%. The incidence was 13.5%. In the foci of infection, out of 497,184 pigs, only 3.4% were destroyed, and more than 83% of pigs remained, among which a high number of virus carriers is likely.

The quality of anti-epizootic measures is questionable, which is consistent with the conclusions of FAO experts, pointing to the lack of veterinary specialists, transport, ineffective supervision and control over eradication programs, insufficient biosecurity, uncontrolled grazing, etc.

There have been repeated reports in the media about the discovery of the corpses of dead domestic pigs in landfills.

settlements, the coast of the sea, along the banks of rivers.

According to the OIE, in 2007 ASF was registered in two northern regions of Armenia bordering Georgia. There were 13 foci of infection in which only 26% of the pigs were destroyed.

According to other sources in Armenia only from August to December 2007, there were more than 40 outbreaks of ASF, where 20 thousand pigs died and were killed.

From these foci, the disease was brought to Nagorno-Karabakh, where the disease was in 79 communities, in which about 9 thousand pigs were destroyed.

In January 2008, the ASF disease in pigs was registered with the OIE in the settlement of Nij, Azerbaijan (40 km from the border of the Russian Federation). In this outbreak, the entire livestock was killed (4734 heads).

In July 2007, ASF was brought to South Ossetia, and by November there were 14 outbreaks, in which 1,600 pigs died and were destroyed, and more than 8,000 pigs were killed in the zone of threat of the introduction of the virus.

In July-August 2007, ASF was registered in 9 settlements of Abkhazia, where more than 31 thousand pigs were killed. In total, more than 39 thousand (87%) pigs were depopulated in the republic.

In November 2007, a case of ASF introduction by wild boars from Georgia to the territory of Russia - the Chechen Republic (Shatoisky district) was registered, and in 2008, the ASF virus was again isolated from wild boars already in two districts of the Chechen Republic (Shatoisky and Urus-Martanovsky).

In June-July 2008, the ASF virus was isolated from wild boars and domestic pigs in 8 locations in the Republic of North Ossetia-Alania. During 2008, more than 10 cases of ASF were registered in the Stavropol Territory among wild boars and domestic pigs in settlements and pig farms. Several foci of ASF have also been identified in the Krasnodar Territory.

CLINICAL SIGNS

Under natural conditions of infection, the incubation period lasts 2-9 days, in the experiment - 1-3 days. The disease proceeds at lightning speed, acutely and chronically. With a lightning current, animals die suddenly. In an acute course, the body temperature rises in animals to 42.5 ° without other visible signs for 2-3 days, and then shortness of breath, cough develop, agitation, serous conjunctivitis are noted. 2-3 days before death, the symptoms become most pronounced: general weakness, depression, rapid breathing, shortness of breath, cardiac arrhythmia; there is no appetite, increased thirst, vomiting, paresis and paralysis of the pelvic limbs, serous and serous-hemorrhagic outflows from the nasal cavity and eyes appear. Diarrhea, feces mixed with blood are sometimes noted, but more often there is constipation, accompanied by proctitis and bleeding from the rectum. The gait becomes wobbly. Tremors, convulsions, clonic convulsions, and paralysis caused by meningoencephalitis are observed in animals. The conjunctiva and mucous membrane of the nasal cavity are hyperemic, the skin in the region of the tail, ears, ventral wall of the abdomen, perineum, the patch is cyanotic with hemorrhages of various shapes and sizes. In the blood, leukopenia, the number of leukocytes decreases to 40-50% of the original. With fulminant, hyperacute and acute course of the disease, mortality and lethality reaches 98-100%. The chronic course of the disease lasts 4-6 weeks and is characterized by exhaustion, sero-catarrhal, lobar pneumonia, exanthema, skin necrosis, arthritis. Mortality 50-60%.

With African swine fever, individual animals survive, they remain susceptible and become ill when experimentally infected.

PATHOMORPHOLOGICAL CHANGES

Rigor mortis sets in quickly and is well expressed. Serous-hemorrhagic conjunctivitis is noted; mucous membranes of a cherry-red color, blood in the nasal cavity and anus. The skin, especially in the area of ​​the ears, eyes, submandibular space, chest, abdomen, limbs, genitals, is purple-blue with multiple hemorrhages. In the subcutaneous and intermuscular connective tissue, around the lymph nodes and along the vessels, serous-fibrinous infiltrates.

In the pericardium, thoracic and abdominal cavities, a yellowish-red color serous-hemorrhagic exudate with an admixture of fibrin is found. The heart is enlarged in volume, the heart muscle is flabby, dull, under the epi- and endocardium there are hemorrhages of various shapes and sizes. The mucous membrane of the nasal cavities, larynx and trachea are swollen, cherry-red in color, riddled with petechial hemorrhages. The nasal cavity, larynx, trachea and bronchi are filled with a pink foamy liquid mixed with blood and mucus. Lungs not slept, airless, plethoric, dark red with a bluish tint, enlarged. Serous edema and multiple spotted hemorrhages under the pulmonary pleura. A symptom typical of ASF is serous hemorrhagic pneumonia with severe swelling of the interstitial tissue.

In the gastrointestinal tract, changes are different in nature, severity and prevalence. The mucous membrane of the oral cavity and pharynx is swollen, cyanotic, with hemorrhages. The mesentery throughout the gastrointestinal tract is thickened due to infiltration with serous exudate, the blood vessels are overflowing with blood. The serous membrane of the stomach is hyperemic, with hemorrhages along the vessels. The mucous membrane is swollen, diffusely hemorrhagically infiltrated, with hemorrhages, focal necrosis, erosion and ulceration (hemorrhagic gastritis).

In the small intestine, hyperemia and swelling of the mucous membrane, especially the ileum. The mucous membrane throughout the small and large intestines is dotted with hemorrhages of various shapes and sizes. In some animals, hematomas are found in the submucosal layer of the rectum, sometimes focal necrosis or ulceration of the mucosa in the areas where hematomas are located. In the caecum and colon, there is serous edema of the intestinal wall, severe congestion and hemorrhages under the serous and mucous membranes.

The liver is enlarged in volume due to increased blood supply, unevenly colored - grayish-yellow areas alternate with dark cherry. In this regard, from the side of the capsule and on the cut surface, it has a nutmeg pattern. Sometimes there are subcapsular hemorrhages, which are usually located on the border with the gallbladder and its excretory duct. The gallbladder is constantly enlarged in volume, filled with thick, viscous greenish-brown bile mixed with blood. Its walls are in a state of serous edema, the mucous membrane is swollen, dark red. There are hemorrhages in the cavity of the bladder, diffuse diphtheritic inflammation.

Perirenal loose connective tissue in a state of severe serous edema. The kidneys are constantly enlarged, with multiple pinpoint and spotty hemorrhages in the cortex and medulla. The walls of the renal pelvis in most animals are thickened due to severe edema and diffuse hemorrhagic infiltration of the mucous layer.

In the bladder hyperemia of the mucous membrane, in some animals - point hemorrhages.

The spleen is enlarged 4-6 times or more. On the section, the pulp is dark cherry in color, the scraping is plentiful, mushy.

The lymph nodes are most severely affected. External and especially visceral lymph nodes are enlarged 2-4 times, softened, black-blue on the outside, the cut surface is dark cherry in color - it resembles a clot of gore.

The vessels of the membranes and the substance of the brain and spinal cord are filled with blood. Along the vessels of hemorrhage, softening of the brain substance is often noted.

In the thyroid, pancreas, adrenal glands and pituitary gland - plethora, hemorrhages and serous edema of organs.

DIAGNOSTICS

The diagnosis of African swine fever is made comprehensively based on the analysis of epizootic data, the results of clinical, pathological and anatomical data and laboratory tests.

Laboratory diagnosis of ASF is carried out by specialized veterinary laboratories for especially dangerous infectious animal diseases or research institutions accredited to work with pathogens of especially dangerous infections.

In our country, laboratory studies on the indication and identification of the ASF virus are carried out by: State Scientific Institution "VNIIVViM", Pokrov; FGU “ARRIAH”, Vladimir.

The following samples are sent to the diagnostic center (in compliance with SP 1.2.036-95 “Procedure for accounting, storage, transfer and transportation of microorganisms of pathogenicity groups 1-4”): spleen, lungs, lymph nodes (submandibular, mesenteric), tonsils, tubular bone (bone marrow ), blood and its serum. To detect the pathogen in the test samples, RIF, PCR are used. Virus isolation is carried out on a culture of porcine leukocytes and porcine bone marrow cells. Identification of the isolated pathogen is carried out using the hemadsorption reaction and the method of fluorescent antibodies. In parallel, a bioassay is carried out on vaccinated and non-vaccinated piglets against CSF. For serological studies, enzyme-linked immunosorbent assay, indirect immunofluorescence reaction, and counter immunoelectrophoresis are used.

IMMUNITY

Surviving pigs remain virus carriers for a long time. Complement-fixing, precipitating, type-specific and delaying haemadsorption antibodies are found in their body. Neutralizing (protective) antibodies are not produced. In this regard, numerous attempts to obtain inactivated or live immunogenic vaccines have not yielded positive results. Live vaccines from attenuated strains of the virus cause in vaccinated animals a chronic course of the disease and prolonged virus carrying, which is dangerous in epizootic terms.

ASF RISK ASSESSMENT IN RUSSIA

As follows from an in-depth analysis of the risk of introducing and spreading ASF to the territory of the Russian Federation from the Transcaucasus, conducted by the Information and Analytical Center of the Federal State Institution "ARRIAH", (Vladimir), the farms of the Southern Federal District are at high risk of introducing the virus and spreading ASF, in which the number of domestic pigs is about 4 million heads and 40 thousand heads of wild boar.

Based on population data on the density of domestic pigs and wild boar, taking into account the correlation of the density of domestic pigs and the road network, the zones of very high risk of introducing and spreading ASF are: North Ossetia, Kabardino-Balkaria, Krasnodar, Stavropol Territories, Belgorod Region, moderate risk: Republics of Karachayevo -Cherkess, Rostov, Volgograd regions.

MEASURES TO PREVENT AND ELIMINATE ASF

All measures for the prevention and elimination of ASF are carried out in accordance with the current instructions approved by the Main Directorate of the Ministry of Agriculture of the USSR on November 21, 1980.

Prevention of the introduction of the disease into pig farms and individual farmsteads

In order to prevent the introduction of the ASF pathogen into pig farms located in the regions of the Russian Federation adjacent to territories that are unfavorable for the disease, it is rational to carry out and subsequently support the following measures:

• transfer them to the regime of closed enterprises with a ban on the walking of pigs (including in the households of the population);
• fence farms;
• equip points for disinfection of vehicles at the entrance;
• provide service personnel with change of clothes and footwear. isolated from production premises, equip sanitary inspection rooms for changing clothes and personal hygiene, as well as places for eating;
• conduct a daily clinical examination of the pig population (in the households - a regular examination);
• conduct laboratory studies to confirm the diagnoses established by clinical and epizootic methods in case of mass diseases of pigs. In accordance with the results obtained, adjust the scheme of preventive measures of the economy;
• all pigs (both in farms and in the backyards of citizens) should be immunized against classical plague and erysipelas;
• prohibit feeding pigs with food waste and confiscated products without heat treatment. To carry out the purchase of feed for pigs from territories free from infectious diseases. Properly equip the places of storage and preparation of feed, with its control and quality. Drinking water for animals must be disinfected;
• limit the movement of animals, with the control of the health status of pigs subjected to transfer;
• regularly, in full (both in the premises for keeping animals and in the adjacent territory) to carry out decontamination, deratization, disinfestation work with monitoring of their effectiveness. Exclude the access of birds, dogs, cats to production facilities and food storage areas;
• slaughter sites, points, as well as autopsy sites, should be equipped in isolation from livestock farms;
• properly organize the disinfection of manure, wastewater, disposal of the corpses of dead animals;
• clean the territory of the farm and the area adjacent to it from manure, garbage.

Action in the event of an ASF outbreak

In the event of ASF, the boundaries of the epizootic focus and threatened zones are determined. The farm, settlement, region, region or republic where the disease is detected is quarantined.

It is forbidden to treat animals sick with African plague. All pigs in the epizootic focus are subject to destruction by a bloodless method. Their corpses, manure, leftover food and low-value inventory, as well as dilapidated premises, wooden floors, feeders, partitions, fences are burned. The premises in which the animals were located, three times, with an interval of three to five days, are disinfected with a solution of bleach containing 4% active chlorine, sodium or calcium hypochlorite containing 2–3% active chlorine, and formol-containing preparations. Carry out disinfection and deratization. In addition, under the terms of quarantine, it is prohibited to import into and export from the territory of animals of all kinds, including birds; procurement and export of raw materials of animal origin, entry to a dysfunctional farm (farm) of unauthorized persons and entry into its territory of transport, as well as regrouping of pigs; trade in animals and products of animal origin in markets and other places; holding agricultural exhibitions and other events related to the accumulation of people and animals.

The first threatened zone-territory immediately adjacent to the epizootic focus of African swine fever, to a depth of 5-20 km from its borders, taking into account economic, trade and other ties between settlements, farms and the epizootic focus;

the second threatened zone is the territory encircling the first threatened zone, up to 100-150 km deep from the epizootic focus.

Activities in the first threatened zone.

All pigs in farms of all categories are immediately registered, heads of farms and owners of animals are warned in writing about the prohibition of the sale, movement and unauthorized slaughter of pigs.

In the shortest possible time, all pigs are purchased from the population and then sent in the same way as the pigs of all other farms, enterprises and organizations in this zone, for slaughter at the nearest meat processing plants or slaughterhouses equipped for this purpose, determined by a special commission. For the transportation of animals, the bodies of motor vehicles and trailers are equipped in such a way as to prevent infection of the external environment along the route.

To accompany groups of vehicles with animals follow: the person responsible for the delivery of pigs, a veterinary specialist and a police officer. Drivers of motor vehicles engaged in the transportation of pigs are issued a sanitary book (coupon), which sets out the procedure for using the transport and makes notes on the veterinary treatments carried out.

In cases where enterprises for the slaughter and processing of pigs are located in the second threatened zone, the regime of the first threatened zone is established around them within a radius of up to 0.5 km. All pigs in this zone are slaughtered on a common basis before the slaughter of pigs imported from the first zone.

Vehicles after unloading the pigs are subjected to mechanical cleaning and disinfection in places specially designated for this purpose. An entry is made about the sanitization of transport carried out in the journal for accounting for this work, as well as a mark in the sanitary book of the driver.

Slaughter of pigs in the first threatened zone is carried out in compliance with veterinary and sanitary rules, excluding the possibility of the spread of the virus.

The skins of slaughtered pigs are disinfected in a saturated (26%) sodium chloride solution, to which 1% hydrochloric acid (in terms of NSE) is added at a disinfectant solution temperature of 20-22°C. Liquid ratio 1:4 (for 1 weight part of paired skins 4 parts of disinfectant solution). The skins are kept in a disinfectant solution for 48 hours and then they are neutralized in accordance with the "Instruction for the disinfection of raw materials of animal origin and enterprises for its preparation, storage and processing." The procedure for their further use in production is determined by the veterinary authorities.

Meat and other meat products obtained from the slaughter of pigs are processed into boiled, boiled-smoked varieties of sausages or canned food.

If it is impossible to process meat into these products, it is disinfected by boiling. The manufactured products are used within the unfavorable administrative territory.

Bones, blood and by-products of the second category (legs, stomach, intestines), as well as slaughterhouse confiscated products, are processed into meat and bone meal. If it is impossible to prepare meat and bone meal, the indicated raw materials are boiled for 2.5 hours under the supervision of a veterinarian and used in poultry feed.

If carcasses with hemorrhages or degenerative changes in muscles, internal organs and skin are found during slaughter, the carcasses with all internal organs are sent for processing into meat and bone meal or destroyed by incineration.

Meat and bone meal obtained from raw materials is used in feed for ruminants and poultry only within the disadvantaged administrative territory.

Prohibit the sale of animals of all kinds, including poultry, as well as trade in the markets of meat and other livestock products. The supply of the population with livestock products is carried out through the state trade network under the control of veterinary supervision.

They ban fairs, exhibitions, and other events related to the movement and accumulation of animals, and sharply restrict the movement of vehicles and people.

It is forbidden to introduce (import) pigs into farms and settlements (yards). The issue of introducing (importing) into farms and settlements, withdrawing (importing) animals of other species from them in each specific case is decided by a special commission.

Establish round-the-clock security and quarantine police or paramilitary posts on all roads leading from disadvantaged areas and epizootic foci of African swine fever to the first threatened zone, and on roads leading to the external borders of the first and second threatened zones. The posts are equipped with barriers, dezobarriers and booths for those on duty.

Activities in the second threatened zone

Prohibit trade in the markets of pigs and pig products. Conduct a recount of the entire pig population. The grazing of pigs is prohibited.

Immunization of pigs against classical plague and erysipelas is carried out in accordance with the plan of anti-epizootic measures.

Strengthen veterinary supervision of the health of pigs in farms of all categories. It is forbidden to send the corpses of pigs and pathological material from them to veterinary laboratories by mail for examination. It is allowed to deliver the material by courier, subject to the relevant requirements.

If there is a suspicion of African swine fever, a special commission is immediately notified, which takes action without waiting for the results of laboratory tests.

In the second threatened zone, the same activities are carried out as in the first.

Removal of quarantine and restrictions.

Quarantine from a farm, point, district (region, territory, republic) that is unfavorable for African swine fever is removed 30 days after the destruction of all pigs in the epizootic focus and the slaughter of pigs in the first threatened zone, other activities provided for by the Instruction.

For a period of 6 months. After the quarantine is lifted, restrictions are set:

It is forbidden to export pork, products and raw materials from their slaughter outside disadvantaged areas, regions, republics by transport of all types.

Citizens are prohibited from selling pigs in the markets of regions, regions (krais), republics affected by ASF, and farms are prohibited from purchasing them from the population.

Post offices of districts, regions, republics unfavorable for ASF are prohibited from receiving parcels from citizens with products and raw materials of animal origin.

During the period of the restrictions on the roads, when leaving the disadvantaged areas, regions, republics, control veterinary and police posts should function.

The acquisition of farms with a livestock of pigs in the former epizootic focus and the first threatened zone is allowed one year after the quarantine is lifted and a negative result of biological control is obtained.

The formed natural foci are kept in quarantine. In agreement with Rosprirodnadzor, ecologists and entomologists carry out entomological control (trapping insects and protecting animals from insects by periodic disinfestation) and, in agreement with hunting supervision and foresters of subordinate forestries, shoot wild boars in the focus of infection.