Prevention and treatment of unknown hyperpyrexia syndrome in pigs

Pig nameless high fever syndrome, that is, pig high fever syndrome, is a disease with high morbidity and mortality, which mainly occurs in mature pigs and some sows. The main clinical manifestations of sick pigs are elevated body temperature, mental depression, loss of appetite or abandonment. Dyspnea, wheezing, some pigs have symptoms such as skin redness and purple, and a few pores have bleeding spots. The main pathogens are mixed infection and secondary infection of various viruses, bacteria and parasites. Include swine fever virus (HCV), porcine reproductive and respiratory syndrome virus (PRRSV), swine influenza virus (SIV), pseudorabies virus (ADV), porcine circovirus type 2 (PCV-II) and Actinobacillus pleuropneumoniae (APP), Streptococcus suis type 2 (SS-II), Haemophilus parasuis (HP), Pasteurella multocida (PM), Mycoplasma suis pneumonia (MH), Toxoplasma gondii, Eperythrozoon, Mixed infection of Salmonella cholerae (SC) and other bacteria in pigs.

Because the etiology of the disease is complex, it is generally a mixed infection of multiple pathogens, which is difficult to control in clinic, and the treatment effect is often not ideal, resulting in slow or stagnant growth of pigs, an increase in the number of diseased pigs and dead pigs, a decrease in feed efficiency, growth rate and overall evenness of pigs, and an increase in treatment costs, resulting in serious losses in production.

I. characteristics of the disease

1. It occurs in the season of high temperature, the course of disease is long, usually about 5-20 days, and the case fatality rate is high.

two。 Pig farms do not attach importance to epidemic prevention, technical staff have a poor concept of health care, there is no strict closure of pig farms, there is no systematic health care for pigs.

3. The body weight of diseased pigs is generally in 20~80kg, the incidence is the highest, and there are also piglets after weaning.

4. The effect of drug treatment is not ideal, and the mortality rate of pig farms with misuse of drugs is higher.

Second, clinical symptoms

The diseased pig's body temperature rose to 40,42.5 ℃, depressed spirit, decreased food intake or loss of appetite, red skin, cyanosis behind the ear, belly and extremities and other skin patches, purplish red; dyspnea, lying in love, some pigs showed severe abdominal breathing, shortness of breath, and some showed wheezing or irregular breathing. Some pigs suffer from runny nose, sneezing, coughing, increased eye secretions, most pigs have tear spots and conjunctivitis symptoms; some pigs have constipation, fecal constipation, spherical, yellow and less turbid urine, dark color. The diseased pigs with a longer course of disease were pale, anemic, rough-haired, some of the diseased pigs had weak hindlimbs, and some sick pigs could not stand before they died, and finally died of convulsions. The mortality rate of diseased pigs is very high, and some pig farms even reach as high as 50-90%. Some sows have miscarriages, stillbirths, weak babies and mummies in the third trimester (100-110 days).

III. Changes in autopsy

All dead pigs showed varying degrees of pneumonia, and autopsy showed the following symptoms:

1. The lungs were swollen and hardened; the lungs were uncontractible rubber-shaped lungs with obvious symptoms of interstitial pneumonia with mottled to brown lesions (marble); most of them were mixed infection pneumonia with suppurative foci, part of pig lung hemorrhage and hemorrhagic pneumonia. the interstitium was significantly widened.

two。 The lymph nodes are widely enlarged, especially the inguinal and hilar lymph nodes.

3. Some dead pigs' livers are swollen and lighter, others are loess and crisp, and some pigs have bleeding spots such as kidney, bladder, throat, coronal sulcus fat and endocardium; some dead pigs' kidneys are enlarged, the color becomes dark, brown or yellowish, the texture is brittle, and there is blood stasis. The spleen of some diseased pigs is enlarged and crisp.

4. Multiple serous fibrinous pleurisy and peritonitis with fibrin exudation in the chest and abdominal cavity. In individual pigs, the pulmonary serosa adhered to the pleura or pericardium.

IV. Prevention and control measures

The cause of the disease is complicated, and the general recovery of diseased pigs is poor. Prevention and treatment should be given priority to, by strengthening feeding management, doing a good job of heat prevention and cooling, health care and prevention in advance, strengthening disinfection, symptomatic treatment and other measures to reduce its morbidity and mortality.

1. Adhere to the principle of self-breeding and self-raising to prevent the purchase of recessive infected pigs.

two。 Attach importance to the feeding and management of pig herds and minimize all kinds of stress factors:

① should do a good job of heat prevention and cooling in summer, increase pig house ventilation and use cold water spray and other cooling measures to promote evaporation and heat dissipation through convection; pig house doors and windows should be all opened to let air convection. When the temperature is high, wash the pig body with cold water or install a spray device, spray 4 times 6 times a day.

② should reduce the feeding density in summer, growing pigs should have more than 0.8m2 living space, the best breeding house should be 1.2m2 / head, and the number of pigs in each column should be about 1012. Keeping reasonable feeding density and cooling can effectively control nameless high fever and respiratory tract disease of pigs.

③ strictly adopts the feeding method of "all in and all out" from delivery, conservation, to breeding, to avoid raising pigs with different ages in mixed groups, and to reduce the number of turning and mixed groups of pigs as far as possible, so that all pigs in the same pig house are transferred out at the same time. After each batch of pigs are out of the pen, the pig house must be strictly washed and disinfected, and then transferred to the new pig group after being left vacant for a few days.

3. Piggery and environment need to be disinfected regularly to reduce the content of pathogenic microorganisms.

As the virus is not sensitive to common disinfectants, especially porcine circovirus, general disinfectants do not work on it. New and less irritating disinfectants, such as compound aldehyde disinfectants, should be selected during disinfection. Within 10 days of the disease, the concentration of disinfectant solution should be increased. The epidemic area and the external environment near the epidemic area should be strictly disinfected 4 or 6 times a day. Sows and large and medium pigs can be sprayed and disinfected at noon. The pig farm life management area was disinfected once a day. Starting from the 10th day, double dilution can be used for disinfection to reduce the chance of healthy pigs infected with influenza and other viruses through the respiratory tract, so as to prevent the spread of the disease and control the spread of the disease.

4. Drug control measures:

The focus of the disease is prevention, when large-scale disease in pigs, the treatment effect is generally not ideal. Antibiotics should be added to feed or drinking water before the occurrence of the epidemic disease, and drugs should be added before the peak period of unknown high fever in pigs. When the epidemic disease occurs, antibiotic treatment of bacteria and mycoplasma can reduce the loss. Early measures should be taken to treat diseased pigs in drinking water and feed at the same time, combined with injection, so as to reduce the death caused by bacterial secondary infection. At present, there are some clinically sensitive drugs in pig farms, such as Zhiyuanjing, and so on. According to the situation of the pig farm, the pig farm can adopt the method of combined use of drugs to formulate the preventive and health care drug use plan of this farm. Control the source of bacterial blight from sow medication.

① for pigs that have occurred "nameless high fever of pigs": florfenomycin + sulfamethoxine 300g / ton can be added to every ton of feed; as the feed intake of diseased pigs is reduced, they can not ingest enough drugs for treatment, and drugs should be added in drinking water at the same time, using a compound preparation of antibiotics and traditional Chinese medicine extract, which is effective to bacteria and viruses, so that pigs can drink freely for 5 days. The sick pigs should be raised in isolation, carefully nursed, and treated with astragalus polysaccharides and long-acting sulfonamides injection twice a day for 3 to 5 days, while adding drugs to drinking water for treatment. If the diseased pigs are co-infected with viral diseases such as classical swine fever, the therapeutic effect is not good. Sick pigs with particularly serious conditions and poor treatment effects should be eliminated promptly and decisively to prevent the spread of the epidemic.

The growth and development period of ②: effective drugs were used for prevention at the age of 12 to 13 weeks and 17 to 18 weeks. Florfenomycin + doxycycline 250g per ton of feed or soluble antibiotics in drinking water were added to drinking water by pulse administration for one week, and then one week after drug withdrawal.

When ③ is in hot and hot weather or when pigs are transferred or vaccinated, anti-stress drugs such as multi-dimensional electrolytes should be added to drinking water to minimize the incidence of disease caused by the decrease of resistance of pigs caused by stress.

④ lactating sows: antibiotics can be added to the sow feed for one week before and after parturition, florfenomycin + lomefloxacin 1000 grams per ton feed for prevention, or 80% net 125g / ton + chlortetracycline 300g / ton + amoxicillin 150g / ton to reduce bacteria excretion from sows to pollute the delivery house and cut off the horizontal transmission of disease from sows to piglets.

⑤ weaned piglets: one week before weaning to 4 weeks after weaning, antibiotics were added to each ton of feed supplemented with florfenomycin + doxycycline 200g / ton, or 80% net 125g / ton + chlortetracycline 300g / ton + amoxicillin 200g / ton was used to cut off the horizontal transmission of disease between piglets and piglets.

⑥ regular deworming: Ascaris, Trichuris and other internal parasites damage the immune system to reduce the resistance of pigs, Ascaris lumbricoides larvae and pulmonary filariasis will aggravate the respiratory disease, so combined with drug deworming is of certain significance to control the development of the disease. 2 weeks after weaning piglets are transferred to nursing homes, deworming agents with obvious effect on parasites in vivo and in vivo should be selected for deworming.