| Haemophilus parasuis disease is a kind of porcine infectious disease which caused by Haemophilus parasuis, and cellulose pleurisy, peritonitis, pericarditis, meningitis and arthritis are mainly pathological features of the disease. Haemophilus parasuisis conditioned pathogen that exists in upper respiratory tract, which will invade the pigs when the resistance of the pigs are low. The diseased often are infected by swine fever and PRRS as secondary infection or mixing with other pathogenies. The diseasemainly attacks 5~8 weeks pigs, and the incidence is around 15%, more than 50% mortality rate in severe cases.In recent years, HPs showed a trend of rising. In order to define the prevalence of the disease in Tianjin area, in this study, serums from different large-scale pig farms in Tianjin region are detected by indirect hemagglutination inhibition test. The serum positive rate of average is 19.81%(62/313), and the positive rate of weaned piglets and conservation of pig is 22.27(47/211). It showed that Haemophilus parasuis is differently prevalent trend in different regions of Tianjin. The results of research will provide important theoretical basis for establishment of prevention and control measures, and show more and more serious infection status of HPs in Tianjin area.In order to define the type and character of the prevalent HPs, Firstly, the study be carried out pathologic autopsy for the suspicious HPs pig. Main organization organs, such as lung, heart, brain, and so on, were collect from sick pigs, and one part of those were used for the preparation of pathological slice, another were used for the separation and identify of pathogenic bacteria. The pathological histology observation revealed the most obvious and serious symptom is the hemorrhage and congestion of lungs, heart, liver. In addition, lung associated with interstitial and cellulose pneumonia, the number of neutrophil increasing. The bacteria were isolated from the samples of sick pigs using TSA solid medium. Under the microscope, the isolated bacteria is ball rod or short rod, arranging in single or short chain. It is gram-negative bacteria, and there is visible capsule. All of these accord with the form and character of HPs. And then the isolated strain was further identified using the special primers which were designed and synthesized according to the 16 Sr RNA of HPs. The colony PCR was conducted to the suspected bacteria, then electrophoresis experiment achieved 650 bp band. There were as high as 99% homologous sequence between isolated strain and Genbank, indicating that successfully isolated 1strain HPs in Tianjin area.In view of the increasingly serious infection situation of HPs in pig farm of Tianjin area, it is important significance to treat the disease through making effective precautionary measures and looking for safe and efficient medicine. Therefore, the study filtrate sensitive drugs for isolated HPs in Tianjin area was used. The results indicated that it was highly sensitive to some drugs, such as ceftiofur, amikacin, ampicillin, ceftriaxone. Combining with other drugs in the treatment and improving the system of prevention and management in pig farms, the application of these drugs obtained ideal results.In a word, The results not only provide theoretical foundation for defining the molecular epidemic regularity of HPs in Tianjin area, but also provide important material basis and technical support for prevention and control in clinic and effective remove for HPs. |
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