Investigation Of Stretococcus Suis Type 2 And Swine Hepatitis E Virus Carried In Healthy Pigs And Pork Products In Shanghai Slaughterhouses

Streptococcus suis type 2 (SS2)and swine hepatitis E virus(HEV)were the major zoonosis pathogeny carried in healthy pigs and pork products. To offer voluble reference data to food safety and health protection of related area, the carry rate of virulent Streptococcus suis type 2 and swine hepatitis E virus was investigated in Shanghai slaughterhouses.1. The investigation of virulent Streptococcus suis type 2 from tonsillar specimens of slaughtered healthy pigs in Shanghai475 tonsillar specimens of slaughtered healthy pigs were collected from 4 Shanghai slaughterhouses from March to November in 2006. 27 strains bacteria were identified as Streptococcus suis type 2 based on bacteria cultural characters, API20 Strep Biochemistry Identification System and PCR assays.Mainly virulent factors of the isolated strains were detected and found that only two strains were cps2/gdh+/epf-/mrp+ and others were cps2/gdh+/epf-/mrp-. The results suggested that the high virulent Streptococcus suis type 2 may be carried by slaughtered healthy pig and the carry rate was 5.7%(27/475),but no high disease-causing Streptococcus suis type 2 strains(MRP+EF+)were isolated from 4 Shanghai slaughterhouses. 2. Both genotype 3 and genotype 4 of Hepatitis E virus were detected in the products of swine in some Shanghai slaughterhousesTo investigate the presence of swine hepatitis E virus (HEV) of several large-scale slaughterhouses in scales in Shanghai.The bile,liver, spleen and lymphonodi mesenterici of 60 swine were collected respectively,160 swine fecal specimen and 61 random sera were collected randomly in four slaughterhouses.The HEV RNA were detected by nested RT-PCR, the HEV positive PCR products were sequenced and sequence analysis was then performed by using bio-software.The positive rate of HEV was 1.08% (5/461), the positive rate of bile was 3.3% (2/60), the positive rate of swine fecal specimen was 0.6% (1/160), the positive rate of random sera was 3.2% (2/61). Sequence analysis showed that the 5 isolates included three genotype 3 HEV strains and two genotype 4 HEV strains.The three genotype 3 HEV isolates were closed to genotype 3 HEV(AB222184) which isolated from Japan wild boar and shared 91.2%-98.6% identity with each other, suggested that they may root from the same predecessor strain. The two genotype 4 HEV isolates shared 94.9% identity to each other and shared 82.5%-87.6% identity with other genotype 4 HEV strains, which suggested that the two genotype 4 HEV formed a subgroup in genotype 4 group and the new isolated two genotype 4 HEV may be the new subtype.