| Swine Streptococcosis is a variety of pig disease can caused by Streptococcus equi ssp. zooepidemicus, S. equi ssp. equisimilis, S. suis, S. porcinus, S. dysgalactiae ssp. equisimilis and other Streptococcus. The major clinical manifestations include septicemia, endocarditis, meningitis, arthritis, lymph node abscess, and the septicemia, of which the most damaging, pigs mortality up to80%under certain incentives action. S. suis type2is the most prevalent type in association with diseases in most countries. It is also an important zoonotic agent for humans in contact with diseased pigs or their products, causing life threatening diseases.Through review of clinical cases from1998to2010, sampling surveys and monitoring of pig farms, we have mastered Streptococcus suis distribution in livestock and space, as well as virulence and drug resistance variation, and Provided the basis for the prevention and control of the disease.After the systemic epidemiological investigation in Shanghai, Jiangsu, Zhejiang, Fujian, Jiangxi, Anhui and other surrounding areas from1998to2010, we found that247(47.78%) were identified as S.suis strains during the517Streptococcus clinical isolates from1998to2010and it had substituted S. equi subsp. zooepidemicus prevailing in China. During the clinical S.suis isolates, the serotype2was most frequent(44.13%) which followed by the serotype9(7.69%),7(3.24%),5(3.24%),3(3.24%),1(2.83%),4(2.83%),25(2.02%). During the healthy pigs isolates, the serotypel5was most frequent(13.24%) which followed by the serotype2(10.5%),29(6.85%),26(5.48%) and3(5.48%. In addition,24(1.45%) S. suis isolates were detected in the air samples from three pig farms, include serotype3(4),29(2),15(1).To investigate the distribution of virulence factors of S. suis isolated from clinical case and healthy pigs, seven virulence genes were detected by PCR, including the glutamate dehydrogenase gene (gdh), the suilysin gene (sly), the extracellular factor gene (epf), the muramidase-released protein gene (mrp), the fibronectin-binding protein gene (fpbs), the glyceraldehyde-3-phosphate dehydrogenase (gadph) gene and the virulence-associated sequence orf2. The results showed the distribution of virulent genes of S.suis in Shanghai was complicated, with12genetypes detected among71serotype2isolates.68.75%of the serotype2clinical isolates and60.76%of healthy isolates were with the genotype of mrp+epf+sly+gdh+gapdh+orf2+fbps+, which were well known to be highly virulent.106clinical isolates of Streptococcus susceptibility test results show that the isolates have produced a variety of antibiotic resistance, highly resistant to Lim amines, tetracyclines, macrolides, aminoglycosides, and40%of the strains have produced Sulfa drugs resistance.34.9%and11.3%of the strains have produced penicillin, ampicillin drug resistance respectively.S. suis infection, an emerging zoonosis, is an increasing public health problem across China and South East Asia. Little is known of the risk factors underlying the disease. To control the risk of S. suis infection, the potential risk factors of S. suis infection were analyzed and a process control system known as "hazard analysis critical control point,"(HACCP) were introduced. Through the epidemiological assessment of this disease, this control study has identified the important risk factors associated with S. suis infection. After Potential risk factors were assessed using HACCP procedure, the Critical control point (CCP-like) were identified, that is carrier pigs, mixed flocks, semen, immunosuppressive disease (PRRS, PCV-2, PR, etc.), vaccine、 drug prevention. For each critical control point to develop appropriate prevention and control measures for prevention and control of S. suis infection technical ideas.In order to control the risk of S. suis infection, according to identified risk factors and critical control points, a comprehensive prevention and control measures were developed for S. suis control in Shanghai. The main control objects and measures were the carrier, vaccine combined with drug prevention, two poin and four segment pigs flow management, PRRS, PCV-2, PR and other immunosuppressive diseases control. The control measures were demonstrated applications and monitored in four farms and two farmers in the Jiading District, Pudong District,, Songjiang District, Chongming County. The results show that the S. suis carrier in the demonstration farms from9.12%(31) decreased to6.47%(22), a decrease of2to3%,and the carrier rate of S. suis type2from1.47%(5) dropped to0.29%(1), the effect was significantly (p<0.05). However, the effect is not obvious in the demonstration farms4. |
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