Investigation And Control Of An Outbreak Of Pig Epidemic Diarrhea In A Pig Farm

In February 2016,diarrhea was outbreak in a breeding pig farm in Liaoning province.Breeding sows,field reserve and piglets were successively infected.The condition of breeding pigs and reserve sows improved after infecting 10 days,while a amount of less than 7-day old piglets were dead of urgent,infectious diarrhea with high mortality rate.In this regard,we carried out a detailed investigation of this diarrhea disease.First of all,epidemiological investigation was carried out in the pig farm.It was the first outbreak of acute infectious disease in this pig farm in the late 8 years.The diarrhea cases before were less infected and sporadic with different symptoms.Indoor environment condition was good which could meet the needs of growing pigs.Farm biosecurity system was completed as well as the full-time veterinary supervision and management.The entrance of people,goods,medicines and vehicles had the corresponding management system.The first infected gilt was imported two months before which had been isolated programmatically.The clinical symptoms of diarrhea cases were markedly among gilts,pregnant sows and piglets.The infectivity was obvious in piglets especially suckling piglets.Most of the infected piglets were within 5 day-old,from one case gradually transmitted to the whole nest.The incidence of infected piglets was characterized by vomiting,watery diarrhea with jet shaped.The vomitus was frequent eating of milk.The course of disease was 3 or 4 days.In the late stage of the disease,the piglets were emaciated and dehydrated,then sluggish,mentally depressed and eventually died.For autopsy of dead piglets,lymph node had no obvious visceral lesions,the main pathological changes part was the small intestine which had catarrhal enteritis.Laboratory diagnosis of piglet feces liquid was carried out using rapid test board.Two plates appeared on the test board which tested positive of PEDV.Further laboratorydiagnosis of piglet feces or dead piglets intestinal contents was carried out by RT-PCR.The results were positive of PEDV and negative of TEGV.According to the medical history investigation,epidemiological investigation,clinical symptom and pathological examination,the disease could be distinguished between physical diarrhea and bacterial diarrhea.For laboratory diagnosis,both of dot immune gold filtration assay and RT-PCR results were positive of PEDV and negative of TEGV.Therefore we could determine that the etiology was PEDV.After accurate diagnosis of PEDV,veterinarian decided to take a series of measures such as back feeding,emergency immunization,preparation of their seedlings,isolation,drug prevention and treatment.Through this series of measures,the piglet mortality dropped from 34.1% to 7.1% after 20 days and the epidemic situation was in control.