| Porcine pseudorabies(Porcine pseudorabies,PR),also known as Ojeski’s disease(Aujeszky’s disease,AD),is an acute infectious disease caused by porcine pseudorabies virus(Porcine pseudorabies virus,PRV).The main clinical diagnostic features of infected pigs were high fever,reproductive disorder and acute encephalitis.Newborn piglets mainly show neurological symptoms,at the same time,PRV can also cause vomiting,diarrhea and other digestive system symptoms in pigs.Recessive infection usually occurs in adult pigs.pregnancy sows infection can cause abortion,stillbirth,mummy fetus,suckling piglets survival rate reduction and respiratory symptoms.The disease can infect a variety of animals,of which pigs are the most sensitive(including domestic pigs and wild boars),the disease is also the most serious,with a high degree of mortality.Among the experimental animals,rabbits and mice were the most susceptible.The popularity of PRV has brought huge economic losses to the pig industry all over the world.So far,PRV has no specific drug treatment around the world,mainly relying on vaccination for prevention.The infection rate of pseudorabies in pigs in China is high.in this study,the ELISA detection and molecular epidemiology investigation of PRV wild virus antibody and immune antibody were carried out by collecting serum and disease materials from some large-scale pig farms in Anhui Province.Multi-dimensional analysis was carried out according to different regions,different times,different growth stages and different scales of sample sources,and the main genes of PRV were selected for genetic evolution analysis in order to understand the prevalence of PRV in Anhui Province.(1)Detection and analysis of serum PRV gE wild virus antibody ELISA in large-scale pig farms in some areas of Anhui Province.In this study,4164 pig sera from 11 large-scale pig farms in Hefei,Wuhu,Bengbu and Anqing in 2017 and 2018 were detected for gE antibody levels by using pseudorabies PRV gE antibody indirect ELISA kit.A total of 1767 blood samples were tested in 2017 and 2397 in 2018.The results showed that the total positive rate of serum gE antibody was 30.2%in 2017 and 28.4%in 2018.A total of 126 pig farms were detected,including 55 pig farms in 2017 and 38 PRV gE antibody positive farms in serum,with a positive rate of 69.1%,and 71 pig farms in 2018,44 PRV gE antibody positive farms in serum,the positive rate was 62%.According to the analysis of four different seasons,the positive rates of PRV gE antibody were the highest in the fourth quarter of 2017(40%and 34.3%)and the lowest in the third quarter(25.6%and 13.8%,respectively).According to different growth stages,the highest positive rate of gE antibody was found in conservation pigs(36.4%)and the lowest in breeding boars(22.2%)in 2017.In 2018,the highest positive rate of gE antibody was reserve sows(35%)and the lowest was boars(19.3%).On the whole,the positive rate of PRV gE antibody in pig farms in Anhui Province showed a downward trend.(2)Detection and analysis of serum PRV immune gB antibody ELISA in large-scale pig farms in some areas of Anhui Province.In this study,2734 blood samples from Hefei,Wuhu,Bengbu,Fuyang and Bozhou were detected by using pseudorabies gB antibody indirect ELISA kit from Hefei,Wuhu,Bengbu,Fuyang and Bozhou in 2017 and 2018,and the number of pig farms was 129.the results showed that 2734 blood samples were collected from Hefei,Wuhu,Bengbu,Fuyang and Bozhou in 2017 and 2018.Among them,a total of 1608 blood samples were detected in 2017,1414 of them were gB antibody positive,the positive rate of serum was 87.9%,56 pig farms were detected,gB antibody was all positive.in the three regions of northern Anhui,southern Anhui and central Anhui,the best immune effect was in northern Anhui.The level of gB antibody was the highest(91.6%)in the second quarter and the lowest(83.7%)in the fourth quarter.among the four seasons,the level of IgG antibody was the highest in the second quarter(91.6%)and the lowest in the fourth quarter(83.7%).The highest level of gB antibody was found in piglets(95.7%)and the lowest in pregnant sows(79.2%).In 2018,a total of 1126 blood samples were tested,1088 of which were gB antibody positive,the positive rate was 96.6%,and 73 of 73,PRV gB antibody positive farms were detected in pig farms.The highest positive rate of serum gB antibody was found in southern Anhui(98.1%),the lowest in central Anhui(95.7%),the highest in the second quarter of 2018(98.2%)and the lowest in the fourth quarter(91.3%).The positive rate of gB antibody in piglets was the highest(98.3%)and the lowest in reserve sows(94.9%).Overall analysis,by 2018,the positive rate of serum PRV gB antibody in the tested areas showed an upward trend,but decreased in some areas.(3)PCR identification and genetic evolution analysis of suspected samples from some pig farms in Anhui Province.A total of 117 samples from pig farms were detected by PCR,and the genes of some positive samples were sequenced.The results showed that the positive rate of PRV was 29.8%in 2017 and 16.7%in 2018.Six positive samples were selected for sequencing,and the nucleotide sequence homology of gE gene among 6 PRV positive samples in Anhui province was 98%≤ 100%.Five strains of gE gene shared more than 98.5%homology with Henan HNQ4 pigs,and one strain had the closest phylogenetic relationship with Beijing BJ-RD.The homology was 99.9%.It lays a theoretical foundation for the study of molecular epidemiology of PRV in Anhui Province.To sum up,the epidemic trend of PRV in Anhui Province is declining year by year,but the situation of PRV prevention and control in some areas is still relatively severe.This study provides technical support and data support for the deep purification of PRV in Anhui Province in the future. |
PDF Full Text Request