Content
Aujeszky virus belongs to the group of herpes viruses, which are very common in nature. The peculiarity of this group is that once they have penetrated into a living organism, they remain there forever. Having settled in nerve cells, herpes viruses wait for the slightest weakening of the immune system in order to activate their activity.
A person also suffers from one of these viruses: "cold" on the lips or "seizures" in the corners of the mouth - a manifestation of the human herpes virus. Human herpesvirus is harmless enough and does not particularly interfere with life, unlike the virus that causes Aujeszky's disease in animals. The Aujeszky virus causes serious economic harm to the entire livestock industry, causing not only the death of livestock, but also abortions in surviving queens.
Infection routes
All animals are susceptible to Aujeszky's disease: both wild and domestic. Its name "pork" only means that it was first isolated from the biomaterial of pigs. Of the household, the most susceptible to the disease:
- piglets;
- pregnant uterus;
- cattle and small ruminants;
- dogs;
- cats.
In these species, cases of the disease almost always end in death.
Basically, animals become infected with the virus by eating the droppings of sick individuals. In piglets, infection can occur through the mother's milk. When kept in too cramped boxes, infection also occurs by contact through open skin lesions (abrasions). Rodents often become infected with the Aujeszky virus due to their widespread cannibalism.
The main carriers of infection on farms are mice and rats. In this case, cats play a double role. By scaring away rodents, they reduce the risk for pigs to contract the Aujeszky virus. But by eating rodents, cats themselves become ill with this infection and become a risk factor.
Aujeszky's disease in piglets
Pigs are infected either from rats (the largest percentage), or from cats with dogs, if they have contact with them. Often, the source of infection is animals with a latent form of the disease or recovered. Pigs, after the disappearance of clinical signs, remain virus carriers for another 140 days. The older the pig was, the longer it remains a virus carrier. Rats - 130 days.
Aujeszky's disease has several more names:
- false rabies;
- pseudo-rage;
- itchy plague;
- mad scabies.
This is due to the fact that the manifestations of true rabies are very diverse and often coincide with the symptoms of Aujeszky's disease.
When the aujeszky virus appears on the farm, up to 80% of the herd can get sick after 10 days. Sometimes everything is 100%. Unlike other types of livestock, pigs have a long-term course of the disease. An interesting sign is that during an outbreak of Aujeszky's disease on a pig farm, rats leave there. But the notion "go away" in this case may not be accurate. Due to the rapid metabolism, the rodents that have brought in the virus have time to die. Such preliminary deaths of cats, dogs and rodents are often observed immediately before an outbreak on the farm.
The virus is characterized by "persistence". Having settled on a farm, he can exist there for several years.More often, cases of the disease are observed in spring and autumn, although there is no strict binding to the seasons.
Localization
After infection, the virus spreads throughout the body, quickly penetrating into the brain and spinal cord. But the first signs of the disease appear in the places through which the Aujeszky virus managed to catch on in the body:
- aerogenic way. Primary localization on the mucous membranes of the pharynx and nose;
- penetration through the skin. Initially, it multiplies in the damaged area, gradually penetrating deeper and deeper into the body. Further, through the blood and lymph, it spreads throughout the body.
During the spread of the virus, fever and vascular disorders are observed.
Symptoms of Aujeszky's disease in pigs
The incubation period can last 2-20 days. Adult pigs tolerate the disease easily, they do not have itching, and the survival rate is very high. During an exacerbation period in sows, calves may be aborted.
Symptoms of Aujeszky's disease in adult animals:
- increased body temperature;
- sneezing;
- lethargy;
- decreased appetite.
Symptoms disappear after 3-4 days. Damage to the central nervous system is very rare.
In piglets, the central nervous system is primarily affected. In young animals, the incidence rate is 70-100%. At the age of 1-10 days, piglets cannot suckle milk, weaken and die within 24 hours. The lethal outcome in piglets under 2 weeks of age is 80-100%.
When infected at the age of 2-16 weeks, the virus infects the central nervous system in piglets. In this case, the following is observed:
- yawn;
- drowsiness;
- inactivity;
- agitation or depression;
- paralysis of the pharynx;
- inconsistency of movements.
Mortality is 40-80%.
Forms of Aujeszky's disease
Pigs can have two forms of the disease: epileptic and ogluoma-like. Both resemble some of the outward manifestations of true rabies.
Due to drooling and death within 20-30 hours, Aujeszky's disease can be easily confused with rabies, unless laboratory tests are performed.
Epileptic form of the disease
Repetition of seizures occurs every 10-20 minutes or when the animal makes noise / shouts:
- striving forward to the stop with the forehead against the wall;
- back bend;
- photophobia.
Before the seizure resumes, the pig first assumes the sit dog pose. Also characteristic in this form are paralysis of the muscles of the body, eyes, ears, lips. Convulsions are observed.
Ogluoma-like form
The term comes from the old name for dropsy of the brain "oglum". The behavior of an animal with Aujeszky's disease in this form is similar to the symptoms of oglum:
- oppression;
- wobbly gait;
- profuse salivation;
- curvature of the neck;
- pulse rate 140-150 beats / min .;
With this form, the pig can stand motionless for a long time, legs unnaturally apart. Depending on age, mortality occurs either after 1-2 days, or within 2 weeks.
Diagnosis of Aujeszky's disease
The diagnosis is made on the basis of the clinical picture and laboratory and pathological studies. At autopsy, they find:
- hemorrhages in the mucous membranes;
- catarrhal bronchopneumonia;
- swelling of the eyelids;
- conjunctivitis;
- blood vessels of the meninges.
After opening, the following is sent to the laboratory to confirm the preliminary diagnosis:
- brain;
- lymph nodes;
- pieces of parenchymal organs;
- placenta and fetus during abortion.
Aujeszky's disease in pigs must be differentiated from:
- plague;
- rabies;
- listeriosis;
- Teschen's disease;
- flu;
- edematous disease;
- food poisoning.
Treatment is prescribed after research. If there is someone left to treat.
Treatment of Aujeszky's disease in pigs
Herpesvirus, like all viruses of this type, cannot be treated. It is only possible to "drive him inside" and achieve remission.
Therefore, even with Aujeszky's disease in pigs, symptoms and secondary infection are treated.Hyperimmune serum and gamma globulin are useless in this case. For the prevention of secondary infection, antibiotics and vitamin preparations are used.
In the case of this herpesvirus, it is only possible to prevent the disease with a vaccine against Aujeszky's disease in pigs. In Russia, you can buy 2 types of vaccine against the pig's aujesky virus: from the FGBI ARRIAH from Vladimir and the vaccine produced by the Armavir biofactory.
Vaccination
The disadvantage is that the timing of immunization and the instructions for use of the Aujeszky vaccines from different manufacturers are very different from each other. When choosing any one vaccine against the Aujeszky virus, you will have to use it until the end of the course. Later it will be possible to change the type of vaccine.
Vaccine from FGBI "ARRIAH"
Produced in vials of 50 doses from the negative strain "VK". Adult livestock are vaccinated according to different schemes, depending on gender and pregnancy. Sows and replacement pigs are vaccinated 2 times with an interval of 3-6 weeks. A single dose of the vaccine is 2 cm³. The last vaccination is done no later than 30 days before farrowing.
In the future, already immunized sows are vaccinated once every 4 months at a dosage of 2 cm³. Vaccination is also carried out no later than one month before farrowing.
Boars are vaccinated every 6 months twice with an interval between vaccinations of 31-42 days at a dose of 2 cm³. Piglets are vaccinated in two different ways:
- Born from immune queens. Vaccinations against the Aujeszky virus are done from 8 weeks using inactivated or live vaccines.
- Born from uterus unvaccinated against the aujeszky virus... Vaccinated in the first days of life. Vaccination is carried out twice with a break of 14-28 days.
This vaccine provides immunization for no more than six months.
In fact, the first one does not differ in its properties from the vaccine of the FGBI "ARRIAH" from Vladimir. The second is close to advertising and provides protection against the Aujeszky virus for 15-16 months. She has a shelf life of 1.5 years.
Virus vaccine "VGNKI"
The duration of immunization is 15-16 months, subject to the vaccination regimens. This vaccine has a rather complex scheme, differentiated by age and well-being / unfavorable conditions of the economy. The vaccine is diluted in the same way as the others: at the rate of 2 cm³ per dose.
Vaccination in a safe farm
Vaccination in a farm unfavorable for the Aujeszky virus
Prevention of Aujeszky virus in pigs
With the threat of the appearance of the Aujeszky virus, prophylactic vaccination is carried out according to the instructions. In case of an outbreak of the disease, the farm is quarantined and a set of measures is taken to disinfect the territory. A farm is considered safe for Aujeszky's disease if a healthy offspring was obtained in it within six months after the termination of vaccination.
Conclusion
Aujeszky's disease, if vaccinated correctly and on time, will not cause serious harm. But in this case, one cannot hope for luck. The Aujeszky virus can be transmitted to any domestic animal.
