Detection And Analysis Of Immune Effect Of Type O Foot-and-Mouth Disease In D County Of Chongqing

Foot-and-mouth disease(FMD)is an animal infectious disease caused by foot-and-mouth disease virus.In 2008,the World Organization for Animal Health classified it as the foremost form of infectious disease,and China classified it as a type of animal sickness.It has a strong infectious power and poses a great threat to the cloven-hoofed livestock industry such as pigs,cattle,sheep,camels and so on.By tracking the antibody-positive rate of pig serum post-vaccination and recognizing the antigen of pig lymphoid tissue in slaughterhouses,one can accurately and promptly gauge the presence of foot-and-mouth disease virus in an area.This is advantageous for implementing more effective prevention and control strategies in production.Foot-and-mouth disease first emerged in E Town,D County,Chongqing in2016.The evaluation of pigs’ immune responses to foot-and-mouth disease vaccination in this region is of utmost importance,and it is essential to supply fundamental information for successful prevention and control of the illness.In order to assess the immune response of pigs in D county of Chongqing to Type O foot-and-mouth disease,2017-2021 saw the completion of spring and autumn prevention in 26 township streets,approximately 21 days later.To assess the antibody of Type O foot-and-mouth disease in live pigs,59 serum samples were collected,with 53 128 positive and 89.40% positive.Annually,the antibody against foot-and-mouth had positive rates of 88.83%,90.14%,89.86%,88.73% and 89.66%,respectively.disease of pigs in different township streets A street 87.93%,B street 91.87%,C town 87.45%,D town 75.90%,E town 91.50%,F town 94.24%,G town 86.06%,H town 95.53%,I town 97.65%,J town 93.48%,K town83.33%,L town 85.37%,M town 81.02%,N town 85.55%,O town 95.82%,P town 92.86%,Q town86.53%,R town 79.44%,S town 88.31%,T town 94.46%,U town 95.66%,V town 95.70%,W town78.19%,X town 88.24%,Y town 87.69%,Z town 91.64% At varying ages,97.23%,88.88%,64.06%,88.97% and 85.32% of suckling,nursing,fattening,breeding sows and breeding boars exhibited positive levels of type O FMD antibodies.Vaccinated pigs,however,did not display such positive rates.from different manufacturers were 89.45% in company An and 89.35% in company B;the positive rate of type O FMD antibody in free-range pigs was 88.57%,and 90.26% in large-scale pig farms.Exploring the disparity in the immune antibody-positive rate of type O foot-and-mouth disease among vaccines of various manufacturers,breeding models,and pigs,we analyze the positive rate in pigs of varying ages,years,township streets,and years.The immune effect is beneficial,with a difference of less than 2% in the positive rate of type O foot-and-mouth disease antibodies between years.In Nanshan township streets,the positive rate of antibodies against type O foot-and-mouth disease is greater than that in Beishan township streets.It is suggested to strengthen the vaccination in township streets in Beishan area.The positive rate of immune antibody against type O foot-and-mouth disease in suckling piglets and nursing pigs is higher than that in fattening piglets.It is recommended that piglets be immunized once a month post-birth and twice in60-65 days,with the vaccine produced by various vaccine producers having no noteworthy variation in antibody level to type O foot-and-mouth disease in pigs.The current situation indicates that the positive rate of type O antibody against foot-and-mouth disease in pig farms is satisfactory.is higher than that in bulk farmers under different breeding modes,it is suggested to strengthen the immunization work of foot-and-mouth disease in bulk farmers.FMDV fluorescence quantitative PCR was employed to detect 165 pig lymph nodes from the three villages and streets with the least immune positive rate of type O foot-and-mouth disease.The results of antibody surveillance and FMDV detection of type O foot-and-mouth disease in D county were all negative,indicating that pigs in the county had not contracted the virus.To sum up,combined with the analysis of the results of type O foot-and-mouth disease antibody surveillance and FMDV detection,it shows that the overall immune prevention and control effect of type O foot-and-mouth disease in D county is good,which provides reliable cases for the local government and animal health supervision departments to effectively prevent and control the disease.