What are the causes and stress factors of swine high fever syndrome?

Causes: Swine high fever syndrome is essentially a swine disease caused by mixed infection with multiple viruses, bacteria and protozoa triggered by immunosuppressive swine diseases.

Biological factors: mixed infection with pathogens such as classical swine fever virus, circovirus, porcine reproductive and respiratory syndrome virus, pseudorabies virus, Eperythrozoon, Toxoplasma, Streptococcus, Salmonella paratyphi, Mycoplasma, Actinobacillus pleuropneumoniae, Haemophilus parasuis and Pasteurella. There can be more than 15 kinds of pathogens, among which classical swine fever virus has the highest infection rate and is the most typical; mixed infection with Toxoplasma, Eperythrozoon, porcine reproductive and respiratory syndrome virus, circovirus and classical swine fever virus is common, and there is also mixed infection of classical swine fever virus with piglet paratyphoid bacillus, often dominated by classical swine fever virus, together with one or more than two kinds of viruses, bacteria and protozoa, so the mortality rate is high, the cure rate is low, and it may even wipe out the whole herd.

Stress factors: high temperature and high humidity climate, high stocking density, poor weaning transition, mixing groups and fighting and biting, long-distance transport, vaccination, stress caused by water deprivation, etc.

Nutritional factors: deficiency and imbalance of vitamins and trace elements in feed, or increased content of growth-promoting liver-damaging elements; moldy feed, with mycotoxins damaging the body; antibiotics and other immunosuppressive drugs added to feed, etc.

Drug factors: First, abuse of antibiotics. Long-term, large-dose and combined addition of antibiotics to prevent swine diseases causes pigs to develop drug resistance, and increases the detoxification burden on the liver and kidneys, damages the normal functions of the liver, kidneys and gastrointestinal tract, and further reduces the pig body's ability to resist diseases. Second, improper medication during treatment. Extensive use of antipyretic and analgesic drugs and immunosuppressive drugs such as dexamethasone treats only the symptoms, not the root cause, aggravates the condition and accelerates death.

Immunological factors: failure to attach importance to routine and scientific immunization with vaccines (bacterins), resulting in poor immunity of pigs after immunization; improper storage, transport and use of vaccines causing immunization failure; indiscriminate injection of vaccines, together with lax disinfection, causing expansion of the epidemic or increased deaths; use of antiviral, immunosuppressive drugs and antibiotics before and after vaccine (bacterin) immunization causing immunization to be ineffective.

Environmental factors: non-standard pig farm construction; unreasonable formulation of disinfection systems and procedures, and inadequate implementation of the systems; failure to attach importance to rodent, mosquito and fly control, and keeping dogs and cats on pig farms, causing spread of epidemic sources; breeding pigs themselves carrying the virus, with inadequate monitoring, culling and purification; selling pigs as soon as they are sick, spreading epidemic sources, so that when pigs in one household become ill, the neighbors suffer.

Prevention: Scientific feeding and management are the prerequisite. Large-scale pig farms should implement scientific production processes and standardized feeding; farmers and small-scale pig farms should use premixes produced by standardized-production enterprises with standardized nutrition. Immunization is the key to disease prevention. A scientific and standardized immunization program should be formulated in light of local epidemics and verified on site, so that it can produce uniform and consistent immunity for the pig herd in the region and on the farm. Drug health care is the guarantee. Drug prevention is very necessary, because there are many kinds of diseases that may occur on pig farms, and it is impossible to immunize against all of them with vaccines; moreover, effective vaccines (bacterins) have not yet been developed for many diseases. When there is no disease, antibiotics should not be used for prevention; probiotic and traditional Chinese medicine health care are advocated. For high fever syndrome, every 2 weeks, 100 milliliters of Yuanlan Wutai can be added to 50 kilograms of water and given to pigs for free drinking for 1 day, and 200 grams of Lanyuan Reduqing can be mixed into 100 kilograms of feed and given to pigs for free feeding for 2 days for prevention; when the weather is hot, add 100 grams of Yingji Su'an to every 100 kilograms of feed and let pigs feed freely to reduce stress reactions. At the same time, pay attention to strengthening disinfection. Formulate a scientific disinfection system and ensure its implementation is in place; regularly test and cull virus-carrying breeding boars and sows to purify epidemic sources; use mechanical rodent control; mix Qiangshou (main ingredients: cyromazine, etc.) into feed at 500 grams per ton of feed, mixing according to the program, to prevent mosquitoes and flies; dogs and cats are prohibited on pig farms. Once swine high fever syndrome occurs, it must be reported promptly to the local government in accordance with the provisions of the Animal Epidemic Prevention Law, and the epidemic must be resolutely and quickly eliminated according to the principle of "early, fast, strict and small."

Treatment 1. Treatment of high fever syndrome caused by classical swine fever virus accompanied by porcine reproductive and respiratory syndrome virus, circovirus, pseudorabies virus, Streptococcus, Pasteurella, Haemophilus parasuis, Eperythrozoon and Toxoplasma: emergency immunization. For pig farms where classical swine fever vaccine immunization is unreliable or has not been done, double-dose emergency immunization with lapinized classical swine fever attenuated vaccine should be carried out under strict disinfection and protection. Mix drugs into feed. Mix 200 grams of Lanyuan Reduqing and 2-5 kilograms of glucose into 100 kilograms of feed and let pigs feed freely for 3-5 days. Inject pigs that do not eat. Inject Xuedongke (main ingredients: sulfamonomethoxine, etc.) intramuscularly at 0.2 milliliters per kilogram of body weight for 2-3 consecutive days; inject Yuanlan Wutai intramuscularly at 0.4 milliliters per kilogram of body weight for the first time and 0.2 milliliters thereafter, twice daily when body temperature is high and once daily after it drops, for 5 consecutive days. 2. For diarrhea and persistent high fever caused by classical swine fever accompanied by piglet paratyphoid, in addition to double-dose emergency immunization with lapinized classical swine fever attenuated vaccine, separately inject Yuanlan Wutai (same dosage as above) and Jinfu Qi'an (main ingredient: florfenicol) intramuscularly at 0.2 milliliters per kilogram of body weight, once daily for 3 consecutive days; at the same time, for the large group, use Lanyuan Reduqing (same dosage as above) and 50 grams of florfenicol mixed into 100 kilograms of feed and let pigs feed freely for 5 days. 3. Symptomatic treatment: If accompanied by hindlimb paralysis, inject Touxiankelin (main ingredient: lincomycin) at 0.2 milliliters per kilogram of body weight and Yuanlan Wutai at 0.2 milliliters per kilogram of body weight intramuscularly, twice daily, and inject vitamin D3 colloidal calcium (for adult pigs) 5 milliliters intramuscularly, once daily, for 5 consecutive days; if accompanied by respiratory symptoms, use Changxiao Mixian (main ingredients: oxytetracycline, etc.) at 0.2 milliliters per kilogram of body weight and Yuanlan Wutai at 0.4 milliliters per kilogram of body weight, intramuscularly once daily for 2-3 consecutive days; if accompanied by neurological symptoms, in addition to intramuscular injection of Xuedongke and Yuanlan Wutai, Qingkailing or Anxie injection should also be used in combination for treatment. During treatment, attention should also be paid to oral or intravenous fluid replacement to improve the therapeutic effect.

At present, the causes of swine high fever syndrome are already very clear. As long as the principle of prevention first is adhered to, disinfection is institutionalized, immunization procedures are standardized, and correct drug prevention and treatment are carried out, and the "five early" measures of "early discovery, early diagnosis, early treatment, early isolation and early elimination of sources" are implemented, and the 24-character guideline of "strengthen leadership, cooperate closely, rely on science, prevent and treat according to law, mass prevention and mass control, and decisive handling" is carried out, high fever syndrome is not difficult to control.