Symptoms and Control measures of Classical Swine Fever

Classical swine fever, commonly known as "intestinal rotting fever", is an acute, febrile and contagious infectious disease caused by classical swine fever virus of the family Flaviridae. It is highly contagious and deadly.

Types of classical swine fever

It usually lasts for 7 days. According to the clinical symptoms, it can be divided into four types: the most acute, acute, chronic and mild.

1. Acute classical swine fever

Pigs with ① disease often have no obvious symptoms and die suddenly, which usually occurs in the area of first onset and the early stage of epidemic.

② pigs showed poor mental condition, fever, body temperature between 40 ℃ and 42 min, showing missed fever, like lying down, hunched back, chills and walking shaking. Loss of appetite or abstinence, like drinking water, some vomiting. Conjunctival inflammation, purulent secretions, the upper and lower eyelids will stick, can not open, nasal purulent nasal discharge. Early constipation, dry and hard fecal ball surface with a large amount of white intestinal mucus, later diarrhea, fecal stench, with mucus or blood, diseased pig nose, retroauricular root, abdomen and extremities inside the skin and gingiva, lip, anus and other mucous membrane needle-like bleeding points, finger pressure does not fade, inguinal lymph nodes enlarged. The boar foreskin is inflamed, the vulva sheath accumulates urine, and the foul-smelling turbid liquid is ejected when squeezed by hand. Piglets can have neurological symptoms, such as molars, recession, rotation, rigidity, lying on the side and swimming, and even coma.

[symptoms] there are varying degrees of bleeding in the skin, serosa, mucosa and internal organs of the whole body. Systemic lymph node swelling

Juicy, congested, bleeding, purplish black appearance, section such as marble, light kidney, needle tip to millet-shaped bleeding points in the cortex, cold stalk in the spleen, mostly at the edge, black and small purple masses in color, larynx mucosa and tonsil bleeding. There are scattered bleeding spots in the bladder mucosa. Gastric and intestinal mucosa showed catarrhal inflammation. A button ulcer is formed at the ileocecal valve of the large intestine.

2. Chronic classical swine fever

Most of them come from acute type, with high and low body temperature, loss of appetite, constipation and diarrhea, gradual emaciation, anemia, weakness, rough coat, weak hind legs when walking, and unstable walking. The ear tip, tail and lower limbs of some diseased pigs become blue-purple or necrotic or fall off, the course of the disease can be as long as more than a month, and finally die, and the mortality rate is extremely high.

[symptoms] the main manifestation is necrotizing enteritis, the change of systemic hemorrhage is not obvious, due to the disturbance of calcium and phosphorus metabolism.

The yellow ossification line formed by ossification disorder can be seen at the end of ribs and the boundary of cartilage tissue in weaned pigs.

3. Mild classical swine fever

Also known as atypical, mainly occurs in weaned piglets and shelf pigs, the symptoms are mild, atypical, the disease is mild, the pathological changes are not obvious, the course of the disease is longer, the body temperature is about 40 ℃, there is no bleeding on the skin, but there are congestion and necrosis, appetite is sometimes good and bad, feces are thin and dry, sick pigs are very thin, the fatality rate is high, and some have been tolerated, but the growth and development is seriously hindered.

Control measures of Classical Swine Fever

[prevention]

1. Vaccination.

2. Carry out immune surveillance, and carry out immune antibody monitoring by enzyme-linked immunosorbent assay or positive indirect hemagglutination test.

3. Eliminate the recessive infected breeding pigs in time.

4. Adhere to the feeding and management system of self-breeding and self-support, all in and all out.

5. Do a good job in isolation, hygiene, disinfection and disinfestation of pig farms and pig houses to reduce the invasion of classical swine fever virus.

Measures to deal with epidemic situation

1. Report immediately and diagnose in time.

2. Delimit epidemic spots.

3. Blockade epidemic spots and epidemic areas.

4. Deal with diseased pigs and make harmless treatment.

5. Emergency vaccination. Presumed healthy pigs in epidemic areas and live pigs in threatened areas are vaccinated against classical swine fever virus.

6. Disinfect, seriously disinfect contaminated sites, enclosures, utensils, etc., accumulate and ferment feces and deal with classical swine fever innocuously.