Detection And Control Of PED In A Pig Farm In Fujian

Porcine epidemic diarrhea(PED)is a disease that is frequently found in pig farm.It is caused by the Porcine epidemic diarrhea virus(PEDV)infection,which lead to an acute gastrointestinal in pigs.It was found that the disease spread fast,the onset was urgent and the mortality was high,among which the infection of Suckling piglets showed the most serious,and the main clinical symptoms were watery diarrhea,vomiting and dehydration.In recent years,the disease has spread widely in China,which lead to great economic losses in the pig industry.In this study,the antigens of swine fever virus,PRRSV,porcine pseudorabies virus,porcine epidemic diarrhea virus,rotavirus,porcine transmissible gastroenteritis virus and Delta coronavirus were detected by PCR and fluorescence quantitative PCR.In order to investigate the propagation path of the PEDV in this farm,the virus load of PEDV in feces-collected from breastfeeding sows,suckling piglets and weaned piglets was detected.Then the target genes were sequenced.At the same time,the quality of water in the pig farm was detected and analyzed.Then,we selected the combined vaccine with TGEV WH-1R strain and PEDV AJ1102-R strain to emergency immunization in all sows.And the enhanced biosecurity measures were enhanced.At last the virus load of PEDV was detected in the feces of suckling piglets.The results are as follows:1.Several piglets showed severe diarrhoea and vomiting in the farm,and the piglets were almost infected in a week.It is suspected that these piglets were infected with virus.PCR results showed that porcine swine fever virus,PRRSV,pseudorabies virus,rotavirus,infectious gastroenteritis virus and Delta coronavirus were all negative,but porcine epidemic diarrhea virus was positive.To analyze whether there were co-infected by PRRSV,pseudo rabies rotavirus,porcine circovirus virus,the quantitative PCR test was used.The results showed that the PRRSV,pseudo rabies rotavirus,porcine circovirus virus were negative,which showed no mixed infection in pigs.The results of virus load detection in three stage pigs showed that the virus load of PEDV more than 1.13×10~3in breastfeeding sows was to 60%,it was to 30%in sucking piglets,and it was to 10%in nurse piglets,indicating that the outbreak PEDV infection in the farm is transmitted from sows to the suckling piglets.2.In order to find if the drinking water in the farm was safe,the quality of drinking water in the pig farm was detected.No pathogenic bacteria were detected in the water samples,the heavy metal content was lower than the limitation,the color,smell and taste indexes all accorded with the drinking standards,which indicated that the drinking water of the pig farm was safe.3.In order to select the suitable vaccine,we sent the PCR production of PEDV S gene to sequence,and analyzed the homology.The results showed that the homology of the isolated strains with 9 PEDV strains in Gen Bank,was from 56.2%to 93.7%,among which the homology with AJ1102 strain was the highest to 93.7%.Then all sows were immunized with the combined vaccine against infectious gastroenteritis virus and porcine epidemic diarrhea virus(WH-1R strain+AJ1102-R strain)and the biosafety measures were enhanced.The results showed that the health level of piglets-produced by the emergency immunization sows were significantly increased,and the positive rate of PEDV in piglets’feces were significantly decreased,indicating that the PED in the pig farm had been effectively controlled.In summary,the pathogen of diarrhea in this farm is PEDV,which is transmitted from sows to sucking piglets.It is of great significance to select a vaccine with high homology between wild strain and vaccine strain for emergency immunization and to strengthen biosafety for the prevention and control PEDV infection.