China Animal Healthy and Epidemic Center

Qingdao, China

China Animal Healthy and Epidemic Center

Qingdao, China

Time filter

Source Type

Gong Z.,China Animal Healthy and Epidemic Center | Zhang L.,Lanzhou University | Lu P.,China Animal Healthy and Epidemic Center | Hu Y.,Lanzhou University | And 2 more authors.
Journal of Animal and Veterinary Advances | Year: 2012

Marek's Disease (MD) is one of the mam infectious diseases that threaten the healthy development of the Chinese poultry industry. The evolution of epidemic strains of the MD Virus (MDV) in China is different from the evolution of strains overseas. The meq gene sequence of pathogenic strains is different from that of the attenuated vaccine strain (MD V-l). The meq saidL-meq gene sequences of the MDV in the lymphoid tissue of chickens in latency period are homologous. The meq gene was only found in the lymphoid tissue of chickens during the onset period. © Medwell Journals, 2012.


Gong Z.,China Animal Healthy and Epidemic Center | Zhang L.,China Animal Healthy and Epidemic Center | Wang J.,Qingdao Agricultural University | Chen L.,Qingdao Agricultural University | And 3 more authors.
Virology Journal | Year: 2013

Background: A severe MD was broken out at a farm in Shandong, China, despite FC126 vaccination of the chickens at 1-day-old. The mortality of the flocks reached up to 38.3%. The infected chickens were found to have MD pathological changes, including enlargement of spleens, livers and kidneys, and tumors occured on organs later. Samples were collected from the chickens for diagnosis. Methods. The collected samples were inoculated into primary duck embryo fibroblast (DEF) cells, and the MDV strain named SD2012-1 was isolated. In order to identify the isolate, amplification by PCR and sequencing of oncogenic Meq and vIL-8 gene were processed, the obtained sequences were compared with the sequences of reference strains, and SD2012-1 was used to challenge immunized SPF chickens. Results: A very virulent MDV isolate strain, SD2012-1, was isolated from a chicken flock in Shandong Province, China, the isolate had the characteristics of very virulent MDV-1, nucleotide and deduced amino acid sequence comparisons of Meq and vIL-8 gene of SD2012-1 with those of reference strains showed SD2012-1 had high homology with MDV strains isolated from China, SD2012-1 could break through the protection provided by HVT vaccine and HVT + SB-1 vaccine immunization and caused the mortality of SPF chickens over 60%. The immune failure occured at the farm could be due to the improper selection of vaccines. SD2012-1 produced death later and the gross postmortem lesions of chickens died early and later were different. Conclusions: MDV strain SD2012-1 isolated from Shandong Province, China was found to have the characteristics of very virulent MDV-1, which could break through the protection provided by HVT vaccine and HVT + SB-1 vaccine, the virus seemed to have a long latent period, and cause different gross postmortem lesions of chickens between chickens died early and later. A better immunization way should be chosen to prevent infection of this MDV strain in field. © 2013 Gong et al.; licensee BioMed Central Ltd.

Loading China Animal Healthy and Epidemic Center collaborators
Loading China Animal Healthy and Epidemic Center collaborators