Molecular Epidemiological Analysis Of Mycoplasma Synoviae And Establishment Of A Newly Isothermal Assay For Detection Of The Bacteria

Mycoplasma synoviae disease is caused by mycoplasma synoviae infection in chickens.Infected chickens have swollen joints,swollen pads,and lameness.Since mycoplasma synoviae was prevalent worldwide,the number of infections increased rapidly with the continuous expansion of infected areas,which caused serious economic losses to the world poultry breeding industry.In order to understand the epidemic status of mycoplasma synoviae in Nanyang city,Henan province,molecular biology technology was used to investigate the epidemiology of mycoplasma synoviae in the chickens in nanyang in 2018.The results showed that 104 samples under investigation in 2018 were tested for mycoplasma synoviae by PCR,and 47 samples were positive,with a positive rate of 45.19%.The total positive rates for the four quarters from q1 to q4 were 29.4%,44%,69% and 47%,respectively.The incidence rate increased in April,July and December,that is,the incidence rate increased during each seasonal transformation,which may be due to the fact that temperature changes are prone to cause respiratory diseases and reduce antibodies in chickens to be susceptible to MS infection.The positive rate of February and March is low.The samples in February may be related to the cold weather and the Spring Festival.The samples in March were not higher than those in other months,which may be due to the improvement of the breeding environment and adequate preventive measures.In other months,it can be seen that the positive rate is relatively high.This phenomenon may be related to the warming weather,the increase of broiler farmers and the gradual expansion of the scale and the failure of preventive measures.Based on the 5 terminal conserved region of vlhA gene of MS,the phylogenetic tree was constructed for 33 strains of mycoplasma synoviae isolated.Except for the two strains,MS180423 and MS181210,which were closely related to the foreign reference sequence B11-85 downloaded from the database,they both belonged to type B.All the other sequences belong to K type on the same evolutionary branch as the domestic reference strains.In this study,a rapid,specific,and sensitive detection assay for Mycoplasma synoviae(MS)was established using a polymerase spiral reaction(PSR)method.A pair of primers were designed according to the conserved region of the vlhA gene of MS,and PSR results were assessed using agarose gel electrophoresis and color rendering with a dye indicator.The optimum reaction temperature and time for PSR using the specific primers were 62?C and 40 min in a water bath,respectively.The sensitivity of the PSR assay for MS detection was 100 times more than that of the polymerase chain reaction assay based on agarose gel electrophoresis results and color change detected by the naked eye.Further experiments demonstrated that the primers specifically detected MS and showed no cross-reaction with other prevalent avian pathogens.Clinical sample testing confirmed that the MS–PSR assay is simple,rapid,specific,and sensitive,and thereby very suitable for application and promotion in the field and laboratories of grassroots units.