Epidemiological investigation of Marek's disease in chicken farms from 2021 to 2022
In order to understand the infection and immune status of Marek's disease virus(MDV)in large-scale chicken farms in China,94 chicken flocks and environmental samples collected from 19 farms in 11 provinces were detected for MDV vaccine and wild virus by quadruplex real-time PCR assay.The results showed that most farms were infected with wild virus,and average positive rate was higher up to 13.6％in Shandong region.The average positive rates of wild virus in samples of white feather broilers,yellow feather broilers,and laying hens from different provinces were 8.3％,3.9％,and 7.2％,respectively.The positive rates of wild virus were higher for laying hens at 1-7 days old,8-14 days old,and 50-80 days old,with 12.6％,13.8％,and 14.3％,respectively.In addition,chicken immunized with the CVI988 vaccine or/and genetic engineering recombinant vaccine rHVT could decrease the positive rate of MDV wild virus,and the wild virus positive rate of chickens immunized with both vaccines was the lowest.The replication of vaccines in feather pouches under different immunization methods showed that the average positive rate of single immunization with CVI988 vaccine was 91.4％at 3-4 weeks of age,and the average positive rate of single immunization with rHVT vaccine was 58.2％.When immunized with both vaccines simultaneously,the average positive rates were 51.8％and 36.9％for CVI988 vaccine and rHVT vaccine,respectively,indicating that chicken farms should effectively carry out Marek's disease prevention.This study enriches the new understanding of the current situation of MDV infection and provides guidance for the prevention and control of Marek's disease in China in the future.
国家科技期刊平台
NSTL
万方数据
