Discussion On Prevention And Control Of Epidemic Diarrhea Of Piglets By PVP-I

Porcine epidemic diarrhea(PED)is an acute highly contagious infectious disease which is caused by the porcine epidemic diarrhea virus.The main clinical symptoms of the disease arediarrhea and vomiting.Pigs of all ages are susceptible.The disease can occurin all seasons,but winter and spring are more common.It is also a disease spreading widely around the world,which has caused severe economic damage to the pig industry.In this study,7 types of PEDVstrains in Guangdong province in spring of 2016 were collected for analyzing the prevalent trend and the genetic variations.By a comparison of the S1 gene with reference strains,we found that the identity between 7 types of PEDV strains and reference strains of CH/GD/2011?LJB/03?Brl/87?Chinju99?C V777 and USA/Colorado/2013 were 89.7%-98.0%?90.3%-97.8%?89.2%-95.3%?89.8%-91.8%?88.0%-94.8% and 90.1%-98.5%,respectively.The 7 types of PEDVstrains have the homology rate of above 87 % with the reference strains.It proves that PEDV epidemicstrains in Guangdong have the characteristics ofdiversity.There are many methods for prevention and control of porcine epidemic diarrhea,such as vaccine immunization,feeding,yolk antibody Ig Y and oral iodine chemicals,etc.After the occurrence of PED in 2011,there is no commercial attenuated vaccine on the market.In order to explore the new method of prevention and control of PED,this study was conducted to explore the effect of the prevention and treatment of PEDV in piglets by using iodine chemicals.Experimental group were divided into the prevention group,the treatment group,the positive group and the blank control group.The prevention group was fed with 4m L PVP-I before 3 days infected with PEDV and the treatment group was fed with 4m L PVP-I after infection.DMEM culture medium was administered in the blank group.Then the piglets were dissected after 7 days with infection.C hanges in body temperature and body weight of piglets were recorded during the period,using fluorescence quantitative PCR to detect the amount of detoxification in prevention group and treatment group,and to detect the viral load of piglets.Ig G PEDV and s Ig A antibody levels in serum and oral liquid of piglets were detected by using ELISA kit.After dissection,the small intestine of piglets wasmade into histopathologicslide.Immunohistochemicaltest and histological observation were carried out.The pathological condition o f piglets was observed.The results showed thatthe amount of excretory virus reached the peak in the prevention group and its control group.Then the amount began to gradually reduce after infection in 2-7 days,but the virus were still positive.The amount of excretory virus reduced in the prevention group after infection in 1-2 days,but the difference was not significant.Compared with the negative control group,the intestinal viral load was decreased in the prevention group and the treatment group of PVP-I and t test analysis showed that the difference was not significant.The Ig G and s Ig A antibodiesin Serum and oral liquid were not significantly different.Histopathological and immunohistochemical results showed that there was no difference between the control group and the prevention group,as well as the treatment group and the control group.These results indicated that the prevention and treatment effect of PVP-I on the piglets infected with PEDV were not ideal.