Causes and symptoms of African swine fever


African swine fever (ASF) is one of the main threats to the well-being of a pig farm. This infection is spread by the virus of three species and massively affects the population of different ages. Infection is accompanied by fever, which can turn into hemorrhagic diathesis, leading in a very short time to necrosis of the internal organs and death of pigs. A solid knowledge of the symptoms, ways of spreading, and the basics of disease prevention will help to significantly reduce farmer risks.

Origin of ASF

African swine fever: the myth or reality of the stories that it first appeared on the “black” continent? Let's investigate together.

The case history is initially linked to Africa, despite widespread opinions about the American origin of the disease. This infection was first registered within the African wild pig population in 1903, so there was nothing American and never in the original origin of the disease. This species of plague came to Europe and America much later.

Spread across countries, the insidious virus has acquired variability of forms and a high propensity for mutations. For these reasons, there is still no adequate treatment and vaccine that would 100% prevent the spread of the infection.

In conditions of the environment, the African plague virus is extremely resistant. It is necessary to destroy it carefully, consistently and systematically. This disease causes enormous economic damage to different countries, aggravating the food problem of individual regions.

Characteristics of the causative agent

African swine fever occurs and manifests itself differently depending on the type of disease. The virus that provokes the infection is subdivided into A, B types and C -species. On the other hand, domestic, wild pigs of any age, sex and breed are infected.

The ASF virus is characterized by significant resistance to high and low temperatures, does not dry out, does not rot. It can be preserved in nature for many years.

The main way to destroy it is a direct effect of formalin or chlorine. In addition, heat treatment of contaminated products showed good efficiency in practice.

Inside the infected meat, fat, blood, by-products, as well as in the corpse of a pig, the pathogen maintains its activity for up to six months. Under favorable environmental conditions and in the freezing stage - up to seven years. At the same time, an animal can become infected at any time of the year.

Ways of spreading the disease

Eating, drinking, minor damage to the skin, which may contain hidden carriers of the virus, provoke infection of the African plague of a healthy pig. The fact that this is possible is evidenced by the numerous facts of epidemics in the branches of the pig-breeding industry, which flare up as a result of, for example, feeding infected pigs to pigs.

Denote the most dangerous factors by which animals can become infected:

  • direct direct contact with a sick individual;
  • meat, other products of slaughtered infected pigs, their carcasses that are stored on the pig farm;
  • food waste, feed that has not undergone sufficient heat treatment;
  • contaminated drinking water;
  • the use of tools on farms without sanitization after use for work inside the infected herd;
  • contact with vectors of the disease, for example, rodents, birds, domestic animals, people;
  • tick bites, gadflies, fleas.

African swine fever does not directly threaten people, but through them the infection can spread rapidly. More information about this can be found in the article "The danger of African swine fever for humans."

External manifestations of infection

During the incubation period, which can last for a month, there are no signs of African plague in pigs. Further manifestations of an infectious disease directly depend on its acute or chronic form.

The most dangerous super-acute type of pathology is when the plague cannot be identified due to the complete absence of symptoms. With such a development of the disease, there are no ailments. There is a sudden death of the pig for no apparent reason.

In the case of acute pathology, the incubation period can last from days to a week. At the same time, such signs of disease as high fever, purulent discharge from the nose, eyes, and ears are noted. All this against the background of weakness, apathy, severe dyspnea of ​​animals. Typical signs of plague are intestinal disorders in which constipations are replaced by diarrhea, vomiting, and bruising behind the ears and on the stomach of gilts.

The hind limbs of the animals are tucked under the abdomen due to muscle atrophy. When a pregnant sow is infected, a miscarriage occurs.

The subacute and chronic form is more difficult, since the symptoms of African plague in a pig mask themselves as other infections. In such cases, they often begin to treat other bacterial diseases, and the animal dies from heart failure.

Symptom variability

Due to the high degree of mutation of the ASF virus, the symptoms of the disease appear in different ways. At the same time, the external picture of the infection may be different for each particular sick boar, pig or small pig.

African swine fever in its atypical form is characterized by weakness, weight loss, diarrhea, fever in animals. Adult individuals and piglets seem to be "sprinkled" with bruises all over their bodies. Conjunctivitis, inflammation of the stomach, intestines, strong skin tightening are characteristic clinical manifestations in this disease.

The most common atypical form is manifested in suckling piglets, which are early separated from the sow, depriving maternal immunity. In addition, young animals infected with a weakly virulent virus strain are also at risk. Some animals recover, many become carriers of the pathogen. With complications in the form of a secondary bacterial infection, the mumps inevitably die. In general, with this type of infection, the mortality of animals is 30-60%.

Diagnosis of the disease

In cases of swine disease, African plague is diagnosed using complex techniques, including laboratory tests. Serological, pathoanatomical methods are used. Fragments of the internal organs of dead animals are studied, blood samples are taken. This allows a high degree of accuracy within the laboratory to identify the disease. It is important to study the biological material in the shortest possible time. To save it is placed inside a plastic bag, which is surrounded by ice.

From the very beginning of the infection, the veterinarians carry out a primary diagnosis, a thorough examination of the animals. African plague can only be identified by taking into account the epizootic situation in the regions. First, a blood sample should be taken from the pigs that have been in contact with infected animals or have been ill for a long time. This group is the most dangerous in terms of the possibility of an outbreak of an infectious focus.

Treatment of a virus that causes a dangerous pathology

If pigs in various farms are diagnosed with African swine fever, then livestock farmers face a real problem, since the treatment of this infectious disease has not been developed, and effective veterinary drugs do not exist.

Control measures focus around early detection of pathology, vaccination. Of great importance is an effective quarantine, which is introduced immediately, as soon as the epidemic of African swine fever begins.

Timely vaccinations will help to partially save the livestock of pigs in pig farms, so they are immediately vaccinated. Within small households, a universal remedy has spread that, in the very early stages of infection, helps to effectively combat ASF. Animals need to pour into the mouth about 150 g of vodka. Extensive practice shows that in many cases the mumps recover.

Preventive measures against the spread of infection

When the slightest signs of infection appear, the determining factor for effective prevention is localization of the source of infection. At the earliest stages of the disease it is necessary to introduce a hard quarantine. This will limit the disease transmitted in the shortest possible time intervals.

All pork livestock is subject to slaughter bloodless method in a radius of 10-12 km from the source of infection, where African swine fever is recorded. Memo to the population states that the meat of slaughtered animals can be used for processing into canned meat. The technology of their preparation involves careful long-term heat treatment.

The corpses of sick pigs, cheap inventory, manure, and problem feeds are burned to complete combustion in the site of the infection. Ashes must be mixed with lime and deeply buried. The most important task is the destruction of rodents, insects, ticks, stray animals, through which this kind of plague is transmitted.

Inside the pig houses it is necessary to carry out a comprehensive thorough disinfection with 2% formaldehyde or hot 3% sodium hydroxide solution. Quarantine is recommended to remove at least six months after the full normalization of the sanitary situation. For a year after an outbreak of infection, it is prohibited to raise pigs in the affected farms.

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