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The Aujeszky virus belongs to a group of herpesviruses that are very common in nature. The peculiarity of this group is that once penetrated into a living organism, they remain there forever. Settling in nerve cells, herpesviruses are waiting for the slightest weakening of immunity in order to intensify their activity.
A person also suffers from one of these viruses: a “cold” on the lips or “bites” in the corners of the mouth are manifestations of the human herpes virus. Human herpesvirus is harmless enough and does not really interfere with life, unlike the virus that causes AD 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.
Ways of infection
All animals, both wild and domestic, are susceptible to Aujeszky’s disease. Its name “pork” only means that for the first time it was isolated from the biomaterial of pigs. Of the household most susceptible to the disease:
- piglets;
- pregnant uterus;
- large and small cattle;
- 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 mother’s milk. When kept in too tight boxes, infection also occurs by contact through open skin lesions (abrasions). Rodents often become infected with the aujeszky virus due to their common cannibalism.
The main carriers of infection on farms are mice and rats. Cats in this case play a dual role. By scaring away rodents, they reduce the risk for pigs of contracting 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 become infected either from rats (the largest percentage) or from cats and dogs if they have contact with them. Often the source of infection are 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 other names:
- false rabies;
- pseudorabies;
- itchy plague;
- mad scabies.
This is due to the fact that the manifestations of real rabies are very diverse and often coincide with the symptoms of Aujeszky’s disease.
When the Aujeszky virus appears on the farm, up to 10% of the herd can get sick after 80 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 AD on a pig farm, rats leave. But the concept of “leave” in this case may be inaccurate. Due to the rapid metabolism, the rodents that carry the virus have time to die. This pre-mortality of cats, dogs and rodents is often seen just before an outbreak on a farm.
The virus is inherently “permanent”. 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
The virus after infection spreads throughout the body, quickly penetrating the brain and spinal cord. But the first signs of the disease appear in places through which the Aujeszky virus managed to catch on in the body:
- aerogenic route. Primary localization on the mucous membranes of the pharynx and nose;
- skin penetration. 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 itch, and the survival rate is very high. During the period of exacerbation in sows, abortion of cubs can occur.
Symptoms of Aujeszky’s disease in adult animals:
- fever;
- sneezing;
- lethargy;
- reduced appetite.
Symptoms disappear after 3-4 days. The central nervous system is very rarely affected.
In piglets, the central nervous system is primarily affected. In young animals, the incidence is 70-100%. At the age of 1-10 days, piglets cannot suckle milk, weaken and die within 24 hours. Lethal outcome in piglets under the age of 2 weeks is 80-100%.
When infected at 2-16 weeks of age, the virus infects the CNS in piglets. In this case, there is:
- yawning;
- drowsiness;
- lack of mobility;
- excitement or oppression;
- paralysis of the pharynx;
- movement inconsistency.
Mortality is 40-80%.
Forms of Aujeszky’s disease
Pigs can have two forms of the disease: epileptic and gluoma-like. Both resemble some of the external manifestations of real rabies.
Due to salivation and death within 20 to 30 hours, AD is easily confused with rabies unless laboratory tests are performed.
epileptic form of the disease
Recurrence of seizures occurs every 10-20 minutes or at the noise / call of the animal:
- striving forward all the way with the forehead against the wall;
- deflection in the back;
- photophobia.
Before resuming the seizure, the pig first assumes a “seated dog posture”. Paralysis of the muscles of the body, eyes, ears, lips is also characteristic of this form. Seizures are observed.
Ogluom-like form
The term comes from the old name for dropsy of the brain “stupid”. The behavior of an animal with AD in this form is similar to the symptoms of stupor:
- 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, the case 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 pathoanatomical studies. When opened, they find:
- hemorrhages in the mucous membranes;
- catarrhal bronchopneumonia;
- swelling of the eyelids;
- conjunctivitis;
- blood-filled vessels of the meninges.
After autopsy, 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;
- influenza;
- edematous disease;
- food poisoning.
Treatment is prescribed after research. If there is anyone 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 it inside” and achieve remission.
Therefore, in the case of AD in pigs, the symptoms and secondary infection are treated. Hyperimmune serum and gamma globulin are useless in this case. Antibiotics and vitamin preparations are used to prevent secondary infection.
In the case of this herpesvirus, only the prevention of the disease is possible with the help of a vaccine against Aujeszky’s disease in pigs. In Our Country, you can buy 2 types of vaccine against the porcine aujeszky virus: from the Federal State Budgetary Institution “ARRIAH” from the city of Vladimir and the vaccine produced by the Armavir biofactory.
Vaccination
The inconvenience is that the timing of immunization and instructions for use for vaccines against auesca from different manufacturers vary greatly 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 gestation. 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 a break between vaccinations of 31-42 days at a dose of 2 cm³. Piglets are vaccinated according to two different schemes:
- Born from immune queens. Vaccinations against the Aujeszky virus are done from 8 weeks using inactivated or live vaccines.
- Born from queens not vaccinated 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 in its properties is no different from the FGBI “ARRIAH” vaccine from Vladimir. The second is almost as advertised and provides protection against the aujeszky virus for 15-16 months. She has a shelf life of 1,5 years.
Virus vaccine “VGNKI”
The term of immunization is 15-16 months, subject to the vaccination schemes. This vaccine has a rather complex scheme, differentiated by age and well-being / disadvantage of the economy. The vaccine is diluted similarly to others: at the rate of 2 cm³ per dose.
Vaccination in a prosperous household
Vaccination in an Aujeszky virus-prone household
Prevention of Aujeszky virus in pigs
With the threat of the appearance of the Aujeszky virus, preventive vaccination is carried out according to the instructions. In the event of an outbreak of the disease, the farm is quarantined and a set of measures is taken to disinfect the territory. The farm is considered free from AD if within six months after the cessation of vaccination it received a healthy offspring.
Conclusion
Aujeszky’s disease, when properly and timely vaccinated, will not cause serious damage. But you can’t rely on luck in this case either. The Aujeszky virus can be transmitted by any pet.