Clinical symptoms, Prevention and treatment of Porcine Encephalitis B

Porcine Japanese encephalitis (je) is a zoonotic disease caused by Japanese encephalitis virus (je). The disease was first found in Japan, so it is also known as Japanese B encephalitis.

Pathogen

The Japanese encephalitis virus is not resistant to the outside world and can be inactivated after 30 minutes at 56 ℃ or 2 minutes at 100 ℃, but it can survive for several years under the condition of minus 70 ℃. When the pH value is less than 7 or more than 10:00, the activity decreases rapidly. Disinfectants such as 2% caustic soda solution and 3% Lysol water are effective for it.

Popular characteristics

Japanese encephalitis virus must be transmitted by blood-sucking female mosquitoes as a vector, and the epidemic link is pig-mosquito-pig. Japanese encephalitis virus can reproduce and survive the winter in mosquitoes, and can be passed on by eggs. Japanese encephalitis virus can infect the fetus vertically through the placenta. Pigs, people, horses, cattle, sheep and so on all have certain susceptibility. Pigs of all ages, breeds and genders are susceptible to the disease, but those before 6 months of age are more susceptible and do not relapse after the disease is cured. The disease has obvious seasonality, which mainly occurs from July to August.

Clinical symptoms

Most of the sick pigs have high fever, depressed spirit or neurological symptoms, loss of appetite, and some have hindlimb paralysis, vision loss, head swinging, random collision and so on. Pregnant sows have a sudden miscarriage, giving birth to stillbirths, weak fetuses and mummified fetuses. Boars often have orchitis, mostly unilateral, the initial swelling has a sense of thermal pain, a few days later the inflammation subsided, testicular atrophy and hardening, decreased libido, semen with poison, loss of breeding ability.

Pathological changes

The endometrium of aborted sows was congested and covered with sticky secretions, a few of which had bleeding spots. The submucosal tissue of uterus of sows with high fever or stillbirth was edema and the placenta showed inflammatory reaction. Meningeal and spinal meningeal congestion can be seen in diseased pigs with neurological symptoms.

Diagnosis.

According to the obvious seasonal epidemiological characteristics, combined with sow abortion, premature delivery, mummified fetus and boar orchitis, it is not difficult to make a diagnosis, but the diagnosis depends on laboratory diagnosis.

Prevention and cure measures

Pig farms should keep more spring births as breeding pigs to avoid first-born sows getting pregnant and giving birth in the mosquito-infested season. Drive mosquitoes and flies, do a good job of isolation and disinfection, cut off the route of transmission. The first dose of attenuated Japanese encephalitis vaccine for immunization is marked by bottle label, 1 ml of special diluent is added to each part, and 1 ml is injected into each pig after it is completely dissolved. The period of immune protection was 12 months. The backup sows and breeding boars in positive pig farms can be immunized once 20-30 days before mating. It can also be prevented about 45 days before the arrival of mosquito and fly season.