Erysipelothrix suis is a gram-positive microorganism, which exists in blood, spleen (viscera), liver (viscera), kidney (viscera) and other organs of dead pigs in pairs or in clusters. Strong anti-drying ability, it can survive in the dark for more than 1 month, in direct sunlight for more than half a month, and in bacon for more than 3 months. General disinfectants and high temperatures can kill germs.
The infection route of erysipelas is mainly through the digestive tract, and skin wounds can also be infected. 3 ~ 12-month-old pigs have the most diseases, while suckling piglets and elderly pigs have fewer diseases.
The incubation period of erysipelas is 1 ~ 5 days. Acute and subacute are more common.
Acute (septicemia): the most common. In the early stage of epidemic, a few pigs often died suddenly without obvious clinical symptoms, while other pigs became ill one after another. The body temperature of sick pigs increased to 42 ~ 43℃; Loss of appetite; Conjunctival congestion with serous secretion; Some sick pigs vomit, start constipation, and then diarrhea; Before the death of some sick pigs, erythema of different sizes appeared on the skin of abdomen and limbs, and the red color subsided by pressing with fingers; Some sick pigs have red skin all over their bodies. Septic pigs can die within 1 ~ 3 days, and the mortality rate can reach 80%.
Subacute (rash type)
The sick pig is a mild one, which is characterized by a rash on the skin in addition to the above general symptoms. The body temperature rarely exceeds 42℃. On/0/~ 2 days after onset, deep red and purplish red rashes of different sizes appeared on the skin behind the ear, on the side of the body, on the chest, on the neck and on the limbs. The rashes were square, diamond, round or irregular, or merged into a large piece. The rash is slightly prominent, with obvious boundaries, which is easy for white-haired pigs to see. With the appearance of rash, the body temperature drops and the condition is alleviated. After a few days, the rash subsided and the last dry scab fell off. The course of rash type is about 10 ~ 12 days, and the mortality rate is low. If not treated in time, sometimes it will turn into acute or chronic. Chronic isolation is rare, mostly from acute transformation. The main symptoms are endocarditis and arthritis or both. The clinical symptoms of sick pigs with endocarditis are not obvious. Sick pigs are stunted, weak, unwilling to walk, have difficulty breathing, palpitations and even collapse when driven away, which are often discovered after autopsy. Arthritis pigs are more common in wrist and tarsal joint inflammation, swelling, initial heat pain, difficulty in walking, even inability to stand, poor appetite and slow growth.
Sick pigs that died of acute erysipelas were red at autopsy; Acute lymph node enlargement, purplish red, juicy slice, bleeding point; The mucosa at the bottom of stomach, duodenum and the front of jejunum is red and swollen with mucus, and bleeding spots can be seen; Acute splenomegaly, soft and purplish red, with medullary protuberance on the section, and the substance is easy to scrape off; The kidney is swollen and uneven purple, and there are red spots the size of a needle cap on the cortical section, and the red spots are slightly raised.
In pigs who died of chronic erysipelas, endocarditis is more common in the left mitral valve, and there are cauliflower-like vegetation on the valve. Changes in arthritis can be seen in sick pigs with chronic arthritis.
In addition to general prevention and control, it is also important to vaccinate pigs regularly every year. There are two kinds of vaccines currently used. All weaned piglets with erysipelas, aluminum hydroxide and formaldehyde vaccines above 10 kg were injected subcutaneously with 5 ml, and the piglets were immunized 2 1 day after injection, and the immunization period was 6 months. Therefore, it should be injected once every spring and autumn. The attenuated swine erysipelas vaccine is a freeze-dried vaccine, diluted with 20% aluminum hydroxide physiological saline, injected subcutaneously into all pigs 1 ml, containing 700 million bacteria. Immunity was produced 7 days after injection, and the immune period was 6 months. When taken orally, 2 ml per head contains 65.438+0.4 billion bacteria. Immunization occurs 9 days after oral administration, and the immune period is 6 months. The advantages of this vaccine are small injection dose, fast immunization and long immunization period. The disadvantage is that the shelf life is short, and the diluted vaccine must be used up within 4 hours, otherwise the bacteria will die and affect the immune effect. Oral administration should be carried out according to the manufacturer's instructions.
It can also be used for injection to prevent swine fever, erysipelas or erysipelas and swine pneumonia.
After the onset, the sick pigs should be isolated and treated in time. (1) Antibiotic therapy Penicillin is the best antibiotic for swine erysipelas. It is effective to use it in large doses in time. The dose of penicillin powder per kilogram of body weight is 10000 ~ 20000 units, and it is injected into muscle 2 ~ 3 times a day. Continuous use for 2 ~ 3 days. After treatment, when the body temperature drops and the appetite and spirit improve, it is still necessary to continue to inject 2 ~ 3 times to consolidate the curative effect.
Oxytetracycline or tetracycline, 30 ~ 50mg/kg body weight per day, intramuscular injection, 65438+ 0 ~ 2 times per day for 3 days.
Streptomycin also has a certain curative effect, 50 mg per kg body weight, intramuscular injection 1 ~ 2 times, daily 1 time. (2) Serum therapy Anti-erysipelas serum can be used for treatment. Piglets 5 ~ 10 ml; Weight: 30 ~ 50ml for medium-sized pigs under 50kg and 50 ~ 80ml for large-sized pigs over 50kg. Subcutaneous or intravenous injection. Serum combined with penicillin is more effective.