In my country, porcine PRRS is classified as a second-class infectious disease with a high incidence rate. The pathogen is porcine reproductive and respiratory syndrome virus. The suitable survival pH of this virus is 6.5 ~ 7.5. It will quickly lose its viability when exposed to high temperature or low humidity and dry environment. Deactivation. Pigs of different genders, breeds and growth stages can be infected, especially piglets and pregnant sows, which are most susceptible to infection, but will not infect other animals. Porcine blue-ear disease is a highly contagious disease with relatively low transmission routes. Many viruses can be spread through the respiratory and digestive systems. Infected pigs can shed the virus and infect other pigs 15 days after infection, causing rapid infection in the pig herd. Infected pigs also have many ways of shedding virus, including semen, nasal fluid, saliva, milk, etc. It can carry viruses, which also contributes to the high contagiousness of pig blue-ear disease. Infected pigs are the main source of infection. Porcine PRRS is endemic. Once a case occurs, it often causes long-term spread of disease in a pig farm. The occurrence of pig blue-ear disease It is not affected by seasonal climate and can occur all year round.

After infection, sows often have symptoms such as high fever, difficulty breathing, lethargy, cough and runny nose, loss of appetite, and sudden decrease in food intake. Infection of pregnant sows will affect reproduction and lead to stillbirths, abortions, premature births, etc. The piglets they give birth to are light and weak, and often die in large numbers before weaning. Sows with abortion experience are less likely to conceive and need to be Time to eliminate. After infection, some sows also develop purple ears, blood spots under the skin, nerve paralysis, and low milk production.

Breeding boar. Severe respiratory tract infections often occur after infection, with rapid respiratory rate and obvious cough symptoms; elevated body temperature, loss of appetite or basically no eating, and red and purple appearance all over the body. However, the duration is short and has a certain impact on the quality of semen.

Because PRRSV will destroy the immune system of pigs, leading to a decrease in the body's resistance, when pigs encounter stress or disease, bacterial infections secondary to PRRS will cause the incidence to peak faster. When testing for PRRSV antibodies, antibody-negative pigs were found to develop severe respiratory symptoms. The disease process is normal in the farrowing room, but fluctuates during the nursery period. The cough and asthma of weak pigs increase, and respiratory symptoms appear soon after they are transferred to the fattening house. The reason is that during the nursery period, the level of maternal antibodies in the pigs decreases, causing secondary bacterial infection, causing respiratory diseases, and thus accelerating death.

African swine fever (ASF) is an acute, severe and highly contagious infectious disease caused by African swine fever virus (ASFV) infecting domestic pigs and wild boars. After pigs are infected, they can be widely distributed in tissues, organs and blood throughout the body, and are discharged into the environment with body fluids such as tears, saliva, nasal fluid, reproductive tract secretions, milk, mucus, etc. Viruses entering the environment are highly resistant to decay and dry environments. Viruses that adhere to normal temperatures can survive for more than 4 months. If the carcasses of sick pigs are not treated harmlessly, the virus will remain alive for 3 weeks.

The clinical symptoms of sows infected with ASFV include high fever, anorexia, dyspnea, skin bleeding, bloody stools, death, abortion and breeding abnormalities, etc. The ovaries play a vital role in sow reproduction. If the ovarian function is damaged, it will cause delayed ovulation or no ovulation. In severe cases, it will lead to ovarian function decline and make the sow infertile.

Gansu Agricultural University research isolated primary granulosa cells (GCs) from the ovaries of healthy sows and collected ovarian tissue from ASFV-infected sows. Fluorescence quantitative PCR method was used to detect the replication of ASFV and the transcription of inflammation-related factors in ovarian tissue infected with ASFV; hematoxylin-eosin (HE) staining and immunohistochemistry (IHC) were used to analyze the pathology of ovarian tissue after infection. Changes and immunohistochemistry of follicle-stimulating hormone receptor (FSHR) and luteinizing hormone receptor (LHR). The results showed that ASFV can infect GCs and replicate in large quantities. Compared with the control group, the transcription levels of inflammation-related factors in ASFV-infected ovarian tissue were significantly increased, and the ovarian corpus luteum and ovarian tissue interstitium were covered with large areas of congestion, lymphocyte infiltration, and luteal cell vacuoles. Chemical degeneration; there is a small amount of macrophage infiltration around the necrotic cells in the follicles. ASFV infection caused a significant decrease in the transcript levels of FSHR and LHR. IHC results showed that ASFV infection caused a significant decrease in the density of FSHR and LHR positive cells in the ovary. The results of this experiment provide a reference and accumulate data for studying the reproductive system lesions and reproductive disorders of sows caused by ASFV infection.

Brucella is a chronic zoonotic infectious disease caused by Brucella infection and mainly affects the reproductive system. Brucella is a Gram-negative bacterium with strong adaptability to the environment. It can attach to feed and enter the body of cattle, destroying the function of the cattle's digestive tract. It can invade through wounds and destroy the health of cattle. It can be contracted through the bite of a mosquito that carries Brucella bacteria. Bull infection can easily reduce sperm motility. Infection in pregnant cows can easily lead to miscarriage and reduce the breeding effect of the farm. Affected cattle may also develop joint inflammation and, in severe cases, lose mobility.

The symptoms of sick cows are relatively complex and diverse, and there are certain differences in severity and specific manifestations. Sick calves often show more obvious symptoms after the onset of the disease. The symptoms of the cows are the most prominent, and most of them are high fever that does not subside, Sudden miscarriage, reproductive failure, etc. Many pregnant cows will even give birth to stillbirths, weak fetuses or mummified fetuses, with problems such as retained fetal membranes and fetal membrane edema. Some more serious cows will also be accompanied by diseases such as mastitis and endometritis, which makes the mother The pregnancy rate of cattle is greatly affected. After the onset of the disease, the bull's reproductive capacity dropped significantly, and the testicles became inflamed, red and swollen.

Since 1984, Guinan County has used MB2 and Sz vaccines to immunize cattle by aerosol and injection for 577,905 times. The infection rate and abortion rate have shown a downward trend, and gratifying results have been achieved. The county's predicted positivity rate in 1990 was 0.14% (1/722). From June to August 1991, we conducted an assessment on the immunization work against bovine brucellosis in Guinan County in accordance with relevant regulations. Serological examination was carried out on 1652 unimmunized cattle over 8 months old, and 6 positive cattle were detected, with a positive rate of 0.36%. The 70 cases of cow aborted fetuses and afterbirths tested were all positive after Brucella culture and guinea pig infection experiments. Negative. The assessment results prove that the prevention and control of bovine brucellosis in Guinan County has reached the control standards. At the same time, it shows that the county's comprehensive prevention and control measures focusing on immunity are correct and feasible, and MBz and S: vaccines are safe and effective.

Trichomonas is a type of protozoa belonging to the phylum Parabasal body and the family Trichomonidae. Its shape is characterized by having 3 to 5 anterior flagella, 1 parabasal body, 1 posterior flagellum connected to the undulating membrane and 1 shaft. as characteristics. Trichomonas infection is common in medical and veterinary clinical settings, and Trichomonas infection in cattle is also common. Bovine trichomoniasis usually refers to a sexually transmitted protozoal disease caused by Tritrichomonas foetus that parasitizes the reproductive organs of cows and bulls. It can lead to premature birth and stillbirth in cattle, causing serious consequences to the cattle industry. significant economic losses.

After T.oetus infects bulls, the parasites parasitize in the sheath of the penis, foreskin and distal urethral epithelium. The characteristic clinical symptoms of acute infection are inflammation and swelling of the foreskin tissue in infected bulls, and occasionally itching of the foreskin mucosa, and Discharge appears. The above symptoms usually disappear within 2 weeks, and then the infected cattle will continue to carry the parasite. The presence of the parasite has no obvious impact on the bull's sexual desire and sperm quality, but it can infect healthy cows through mating. After cows are infected with T. foetus, clinical symptoms vary in severity, ranging from asymptomatic to severe reproductive failure and abortion. Infected cows often suffer from cervicitis, vaginitis, intrauterine abdominal salpingitis and placental inflammation. Among them, the most obvious inflammatory changes appear in the parts most closely related to pregnancy and conception, that is, the endometrium and fallopian tube. In addition, T. foetus infection can cause gastrointestinal pathological changes in fetuses with ambulatory discharge, such as intestinal mucosal epithelial damage and shedding. Research shows that after cows are infected with T.butteryi, the parasites can only be detected intermittently in the reproductive tract, and there is no obvious damage to the reproductive tract tissue. When artificially infected with T.butervi, the parasites cannot survive in the reproductive tract of bulls. When naturally infected with Tbutervi, the worms can be briefly detected in the reproductive tract of bulls. Vaginal inoculation of estrous cows with P.hominis failed to establish infection.

Some studies have used acriflavine, Diminazeneaceture, acriflavin ointment, chlorhexidine (i.e., chlorhexidine) and metronidazole (trichomonad) to treat bovine trichomoniasis, but these drugs may It has poor efficacy or is troublesome to use and has rarely been used. Although Dimetridazole is effective in killing Trichomonas, it has side effects such as rumen bleeding, dyspnea, and collapse and is banned.

Sheep brucellosis has the most obvious symptoms and is most likely to infect humans. After this pathogen infects sheep, it mainly manifests symptoms such as abortion, infertility, and reproductive failure in female animals. The disease is highly contagious and spreads quickly. Once it appears, it is difficult to control, causing huge economic losses to the breeding industry and seriously endangering the development of animal husbandry and public health safety.

The incubation period of sheep brucellosis is about half a month, and in a few cases the incubation period is as long as several months or a year. Sick animals usually show latent infection, with no obvious clinical symptoms. In the early stage of the disease, the body temperature rises, the spirit is listless, and the symptoms appear. Symptoms such as arthritis, tenosynovitis, synovitis, conjunctivitis, etc. Before abortion, the labia and breasts of the affected ewes are swollen, the vagina is swollen and congested, and there is yellow or gray-brown foul-smelling mucus flowing out of the vagina, which appears around 3 months of pregnancy. Abortion, most fetuses are stillborn, and symptoms such as endometritis and pyometra appear after abortion. Affected rams develop orchitis.

In order to control the occurrence of brucellosis, vaccine immunization often selects uninfected healthy animals. During the autumn prevention in 2022, a sheep farm in Gansu conducted a comprehensive serological Brucella antibody test on the sheep and screened out Brucella antibodies. Negative sheep were orally immunized with S2 vaccine, and then grazed normally and inbred bred. However, with the arrival of the lambing season in the second year, mass abortions still occurred in the sheep flock. In order to find out the causes of abortion, serological and pathogenic tests were carried out on serum and vaginal swab secretions of aborted sheep and infertile sheep, and species identification, drug resistance gene detection and other research were conducted to analyze The causes of mass abortions provide guidance for the next step in epidemic prevention and control.

Toxoplasma gondii is an important zoonotic parasite that can infect a variety of warm-blooded animals (including dogs, cats, cattle, sheep, pigs, etc.), but the final host is felines. Toxoplasma gondii is widely distributed in different regions of the world. Cattle, sheep and other animals are infected with the pathogen by accidentally eating forage containing Toxoplasma gondii oocysts or drinking water contaminated by Toxoplasma gondii oocysts. Cattle and sheep infected with toxoplasmosis may develop a variety of clinical symptoms, such as reproductive failure and dyspnea. In addition, Toxoplasma gondii can also infect people. Infection of pregnant women with this pathogen can lead to fetal miscarriage and developmental abnormalities. Infection of patients with low immunity can cause systemic infection and even threaten the patient's life. Therefore, the widespread epidemic of toxoplasmosis will pose a huge threat to the development of my country's livestock and poultry breeding industry and public health.

Many sheep are in a latent carrier state after infection, and a few cases will show respiratory symptoms and neurological symptoms, such as difficulty breathing, constant coughing, wheezing, constant salivation in the mouth, frequent discharge of large amounts of nasal fluid from the nostrils, unsteady walking, decreased vision, and heartbeat. Acceleration, body temperature remains high for several days, feed intake decreases, rumination decreases or stops, indigestion and diarrhea, etc. Pregnant ewes will suffer miscarriage after infection, with severe fetal membrane lesions, dark red villi, and white necrosis on the surface. The stillborn fetus has subcutaneous edema, excessive fluid in the body cavity, intestinal congestion, and extensive non-inflammatory small necrotic spots in the meninges. Toxoplasma gondii can be seen in the examination of the aborted tissue. Necropsy of dead sheep shows enlarged lymph nodes, small nodules on the edges, scattered bleeding spots in the lungs, widening of the interstitium of the lungs, fluid accumulation in the chest and abdominal cavities, and smear examination of the liver, lungs, spleen and lymph nodes. body.

A survey by Feng Yun et al. found that the average positive rate of Toxoplasma antibodies in semi-fine-haired goats in Yongshan County, Yunnan was 44.9% (92/205), with no significant difference in the positive rates of sheep of different ages and genders; a study by Yan Xinlei et al. found , the serum Toxoplasma antibody positivity rate of Hulunbuir grazing sheep was 12.07% (71/588), among which the Toxoplasma antibody positivity rate of samples at different age stages was significantly different, but the difference between different genders was not significant; while the survey by Xing Dongyang et al. [6] The results found that the positive rate of Toxoplasma gondii antibodies in Tibetan sheep in some areas of Qinghai Province was only 2.21% (6/272). The above research results show that sheep toxoplasmosis is widely prevalent in my country, but the epidemic characteristics of different regions are quite different. Therefore, investigating the epidemic characteristics of sheep toxoplasmosis is very important for the prevention and control of the disease. In recent years, the sheep breeding industry in Yulin City, Shaanxi Province has developed rapidly, but there is a relative lack of investigation reports on the prevalence of toxoplasmosis in sheep in Yulin City.

infectious factors

non-communicable disease factors