Biomaterial Database

A Chinese Variant Marek's Disease Virus Strain with Divergence between Virulence and Vaccine Resistance. 2017

Guo-Rong Sun, and Yan-Ping Zhang, and Hong-Chao Lv, and Lin-Yi Zhou, and Hong-Yu Cui, and Yu-Long Gao, and Xiao-le Qi, and Yong-Qiang Wang, and Kai Li, and Li Gao, and Qing Pan, and Xiao-Mei Wang, and Chang-Jun Liu

Division of Avian Immunosuppressive Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin 150069, China. sgrshenhua@hotmail.com.

Marek's disease (MD) virus (MDV) has been evolving continuously, leading to increasing vaccination failure. Here, the MDV field strain BS/15 was isolated from a severely diseased Chinese chicken flock previously vaccinated with CVI988. To explore the causes of vaccination failure, specific-pathogen free (SPF) chickens vaccinated with CVI988 or 814 and unvaccinated controls were challenged with either BS/15 or the reference strain Md5. Both strains induced MD lesions in unvaccinated chickens with similar mortality rates of 85.7% and 80.0% during the experimental period, respectively. However, unvaccinated chickens inoculated with BS/15 exhibited a higher tumor development rate (64.3% vs. 40.0%), but prolonged survival and diminished immune defects compared to Md5-challenged counterparts. These results suggest that BS/15 and Md5 show a similar virulence but manifest with different pathogenic characteristics. Moreover, the protective indices of CVI988 and 814 were 33.3 and 66.7 for BS/15, and 92.9 and 100 for Md5, respectively, indicating that neither vaccine could provide efficient protection against BS/15. Taken together, these data suggest that MD vaccination failure is probably due to the existence of variant MDV strains with known virulence and unexpected vaccine resistance. Our findings should be helpful for understanding the pathogenicity and evolution of MDV strains prevalent in China.

UI	MeSH Term	Description	Entries
D008380	Marek Disease	A transmissible viral disease of birds caused by avian herpesvirus 2 (HERPESVIRUS 2, GALLID) and other MARDIVIRUS. There is lymphoid cell infiltration or lymphomatous tumor formation in the peripheral nerves and gonads, but may also involve visceral organs, skin, muscle, and the eye.	Fowl Paralysis,Marek's Disease,Fowl Paralyses,Mareks Disease,Paralyses, Fowl,Paralysis, Fowl
D002645	Chickens	Common name for the species Gallus gallus, the domestic fowl, in the family Phasianidae, order GALLIFORMES. It is descended from the red jungle fowl of SOUTHEAST ASIA.	Gallus gallus,Gallus domesticus,Gallus gallus domesticus,Chicken
D002681	China	A country spanning from central Asia to the Pacific Ocean.	Inner Mongolia,Manchuria,People's Republic of China,Sinkiang,Mainland China
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D014765	Viral Vaccines	Suspensions of attenuated or killed viruses administered for the prevention or treatment of infectious viral disease.	Viral Vaccine,Vaccine, Viral,Vaccines, Viral
D014774	Virulence	The degree of pathogenicity within a group or species of microorganisms or viruses as indicated by case fatality rates and/or the ability of the organism to invade the tissues of the host. The pathogenic capacity of an organism is determined by its VIRULENCE FACTORS.	Pathogenicity
D017211	Treatment Failure	A measure of the quality of health care by assessment of unsuccessful results of management and procedures used in combating disease, in individual cases or series.	Failure, Treatment,Failures, Treatment,Treatment Failures
D025922	Mardivirus	A genus in the family HERPESVIRIDAE, subfamily ALPHAHERPESVIRINAE, associated with malignancy in birds.	Marek Disease-like Viruses,Marek's Disease-like Viruses,Mardiviruses,Marek Disease like Viruses,Marek's Disease like Viruses,Mareks Disease-like Viruses