The Epidemiological Investigation Of Streptococcus Suis Isolated From Healthy Pigsin Jiangsu Province In 2017

Streptococcus suisis a pathogen that can lead to common infection between swines and humans.The classification methods of Streptococcussuis have a lot,but there are two frequent methods used by us at present.First,the bacteria according to the antigen of the capsular polysaccharide,falls into 33 serotypes and some unqualified isolates..S.suis has a lot of serotypes,of which some are reported that they contribute not only to animal disease,but also to human illness and death.Second,S.suis was classified by MLST,which is characterized by concreteness and convenience.It is also conducive to communication between the various laboratories.S.suis once broke out in Jiangsu Province in 1998,and here was a high carrying area of S.suis.Therefore,it is very important for the epidemiological investigation of S.suis disease,the epidemic situation of S.suis is also an important reference for the daily control and the study of the epidemic law of S.suis disease.We selected eight farms and collected nasal swab samples(15 copies of 20 days and 60 days swine swabs)in Jiangsu province.S.suis was detected by PCR method.We concluded that the detection rate of S.suis was 60.42%in Jiangsu province in 2016.The detection rate of S.suis was 69.71%in the 20 days swine.The detection rate of S.suis was 51.66%in the 60 days swines.YK farm detection rate was 26.67%,of which 20 days swineswere 40%,60 days swineswere 13.33%.SN farm was 63.33%,of which 20 days swines were 60%and 60 days swines were 66.67%.HJ farm was 13.33%,of which 20 days swines were 13.33%and 60 days swines were 13.33%.MX farm is 50%,of which 20 days swineswere 60%,60 days swineswere 40%.HD farm was 93.33%,of which 20 days swines were 100%and 60 days swineswere 86.67%.QK farm was 90%,of which 20 days swines were 93.33%and 60 daysswines were 80%.DX farm was 70%,of which 20 days swines were 80%and 60 days swines were 60%.QX farm was 76.67%,of which 20 days swines were 100%and 60 days swines were 53.33%.The detection rate of S.suis was different among the farms,and the detection rate of swine lets at 20 days swines was higher than that of 60 days swines.We selected eight farms.We collected and cultured in nasal swab samples in Jiangsu Province.The serotypes were detected by PCR.We selected major pathogenic serotypes(1,2,7,9)and serotype(3,5,8,21)isolated from diseased swines in Jiangsu province.The results were as follows:the detection rate of YK farm was 40%,SN farm was 13.33%,HJ farm was 0,MX farm was 36.77%,HD farm was 70%.QK farm was 60%.DX farms was 73.33%.QX farms were 76.67%.A comparison was made in the serotypes of nasal swab samples from 20 daysswines and 60 daysswines,the detection rate of pigs aged 20 days was higher than that of 60 days pigs.Comparative serotype and non-dominant serotype revealed no significant difference in the detection rate of non-dominant sera and dominant serotypes.We selected four pig farms for medicine prevention and collected nasal swab samples in Jiangsu province.The detection rate of the 20days nasal swab was 50%in the control group,and that of the 60 days of nasal swab samplesin the untreated group was 83.33%.60 days of nasal swab samples separately were 40%and 56.67%.By comparison,it was found that the detection rate of Streptococcus suis was significantly lower than that of pig farms that had not been prevented.The serotypes SS1,SS2,SS3,SS5,SS7,SS8,SS9,SS21were compared between the experimental group and the blank group.The serotype of the experimental group was also significantly lower than that of the control group.Three pig farms were selected for vaccine immunization.At 20 days of age,30 copies of nasal swabs marked the numberon their ears,60 days of age 15 copies of nasal swab samples were to detect the infection rate of S.suis.28 days later,and then we collect the marked 30 pigs swab to test.The results showed that the vaccine was better in HD and QK farms.But the detection rate of the immunized group in the MX group was higher than that in the control group.And then a comparison between the 20days swine and 60 days swine nasal swab samples for each pigwas made.Healthy herds were identified for bacterial isolation in Jiangsu province.We selected five pig farmsin Jiangsu province,90 nasal swab samples were totally collected,bacterialculture,and identified by PCR.51 strains were isolated SS3(1.96%),SS9(5.88%),SS21(33.33%).22strain of Jiangsu isolates were identified by MLST.The results showed that the MLST typing of the homozygous serotypes from healthy pigs and diseased pigs was not the same.The virulence factors of the same ST strain was not the same.The virulence factors of the same serotype strain are not the same.75%of the popular SS2 strain is ST7.1t is the same as the ST-type pathogen of the outbreak of Streptococcus suis in Sichuan in 2005.