Glässer's disease is a bacterial disease of pigs

Glässer's disease, also known as fibrinous polyserositis and arthritis, is caused by a Gram-negative coccobacillus and presents as sporadic polyserositis and arthritis. With the development of the world's @#@227@#@ industry, the application of intensive farming techniques and highly dense rearing, as well as the emergence of new respiratory syndromes and other factors, the disease has become increasingly prevalent and its harm increasingly serious. In the past two years, reports of Haemophilus parasuis causing polyserositis and arthritis in pigs on pig farms in China have been common, especially on large-scale pig farms where, after infection with blue ear disease, circovirus disease and the like leads to a decline in immune function, Glässer's disease takes the opportunity to break out, causing relatively serious economic losses.

[Epidemiology]

Haemophilus parasuis mainly affects young pigs after weaning and during the nursery stage, with an incidence generally of 10%-15%, and in severe cases the mortality rate can reach 50%. The bacterium parasitizes the upper respiratory tract such as the nasal cavity; it is an opportunistic bacterium and can be induced by many factors. Infected pigs or carrier pigs mainly infect other healthy pigs through the air and direct contact; other transmission routes such as the digestive tract can also cause infection. At present, only relatively large laboratories carry out laboratory testing, so ordinary pig farms cannot easily obtain a correct diagnosis in time. Analysis of the occurrence of this disease shows that it is greatly related to the pigs' resistance, environmental hygiene and rearing density on the farm. If pigs have had blue ear disease and the like, when resistance declines, Haemophilus parasuis easily takes the opportunity to invade; when pig herds are dense, overcrowded, the air in the barn is foul and the ammonia smell is strong, it occurs frequently during regrouping, mixing or transport. When pigs have respiratory diseases such as mycoplasmal pneumonia, swine influenza, pseudorabies and porcine respiratory coronavirus infection, the presence of Haemophilus parasuis can exacerbate their condition and complicate the disease.

[Clinical symptoms]

1. Acute form: it often first occurs in pigs in good body condition. Sick pigs have fever, with body temperature rising to 40.5°C-42.0°C, mental depression, slow response, decreased appetite or anorexia, coughing, difficulty breathing, abdominal breathing, accelerated heartbeat, red or pale skin on the body surface, purplish ear tips, subcutaneous edema of the eyelids, and some sick pigs show purulent nasal discharge, walk slowly or are unwilling to stand, develop lameness or unilateral lameness, swelling of the carpal and tarsal joints, and ataxia; before death they lie on their side or their limbs make paddling movements. Sometimes they may also die suddenly without obvious symptoms, and in severe cases sows may abort. When arthritis occurs, one or several joints can be seen to be swollen and hot, painful in the early stage, mostly in the carpal and tarsal joints, with difficulty standing up and uncoordinated hind limbs.

2. Chronic cases are mostly seen in nursery pigs, mainly with decreased appetite, coughing, difficulty breathing, rough and messy coat, weakness of the limbs or lameness, poor growth, and even death from exhaustion.

[Necropsy changes]

On dissection, polyserositis such as pleurisy, peritonitis, meningitis, pericarditis and arthritis can be seen, with fibrinous or serous exudation, increased pleural fluid and ascites, swollen, hemorrhagic and congested lungs, and sometimes adhesion between the lungs and the thoracic cavity; these phenomena often appear in different combinations and rarely exist alone.

[Diagnosis]

A preliminary diagnosis can be made based on the epidemiological situation, clinical symptoms and necropsy lesions (especially the necropsy lesions); a definitive diagnosis requires bacterial isolation and identification or serological testing. In terms of serological diagnosis, mainly agar diffusion test, complement fixation test and indirect hemagglutination test are used. This disease is mainly distinguished from infectious pleuropneumonia: the lesions caused by Haemophilus parasuis infection include meningitis, pleurisy, pericarditis, peritonitis and arthritis, and are polyserositic; whereas the lesions caused by typical infectious pleuropneumonia are mainly fibrinous pleurisy and pericarditis, and are confined to the thoracic cavity.

[Prevention and control measures]

Once a pig farm has obtained a correct diagnosis or obvious clinical symptoms appear, a large dose of antibiotics must be used for treatment, and drug prevention should be carried out for the entire herd or the same group of pigs; most Haemophilus parasuis is sensitive to ampicillin, fluoroquinolones, cephalosporins, tetracyclines, gentamicin and potentiated sulfonamides, but is resistant to erythromycin, aminoglycosides, spectinomycin and lincomycin.

When this disease occurs on a pig farm, the following measures can be taken:

① Isolate all sick pigs in the barn and cull runts or severely sick pigs with no rearing value; wash the barn clean, disinfect strictly, improve the ventilation conditions of the barn, disperse the herd, reduce density, and strictly prohibit mixed rearing.

② Medication for the whole herd: amoxicillin 400 g, 5% Pulejian 1000 g, chlortetracycline 2000 g per ton of feed, fed continuously for 7 days, stopped for 3 days, then fed for another 3 days. Or choose one to two drugs from tiamulin 50-100 PPM, florfenicol 50-100 PPM, Chubingsha 1000 PPM, lincospectin 44-1000 PPM, tylosin and sulfadimidine 100 PPM each, lincomycin 200 PPM, ciprofloxacin 150 PPM, etc., and mix them into the feed.

③ For the isolated sick pigs, those that can eat feed are treated as above; for those that do not eat or have poor appetite, amoxicillin 200 g per ton of water can be added to the drinking water instead, and a quinolone drug or 30% Pulejian injection 3.5-7.0 mL/10 kg body weight can be injected intramuscularly.

④ Eliminate various predisposing factors, improve feeding management and environmental disinfection, reduce various stresses, and in particular do a good job in preventive immunization against swine fever, pseudorabies, blue ear disease and the like.

⑤ Immunization: for prevention, an inactivated vaccine can be used to immunize sows; for first immunization, one dose at 40 days before farrowing and a second dose at 20 days before farrowing. For previously immunized sows, one immunization at 30 days before farrowing is sufficient. On pig farms seriously threatened by this disease, piglets should also be immunized; pigs from 10 days to 60 days of age should all be injected, 1 mL each time, and it is best to repeat the injection once 15 days after the first immunization.