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ARS Home » Southeast Area » Athens, Georgia » U.S. National Poultry Research Center » Endemic Poultry Viral Diseases Research » Research » Publications at this Location » Publication #384358
Research Project: Intervention Strategies to Prevent and Control Enteric Diseases of Poultry

Location: Endemic Poultry Viral Diseases Research

Title: Pathogenic evaluation of a turkey coronavirus isolate (TCoV NC1743) in turkey poults for establishing a TCoV disease model

Author
item KANG, KYUNG-IL - Orise Fellow
item DAY, JAMES - Food Safety Inspection Service (FSIS)
item ELDEMERY, FATMA - Orise Fellow
item Yu, Qingzhong

Submitted to: Veterinary Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/16/2021
Publication Date: 6/18/2021
Citation: Kang, K., Day, J.M., Eldemery, F., Yu, Q. 2021. Pathogenic evaluation of a turkey coronavirus isolate (TCoV NC1743) in turkey poults for establishing a TCoV disease model. Veterinary Microbiology. 259:109155. https://doi.org/10.1016/j.vetmic.2021.109155.
DOI: https://doi.org/10.1016/j.vetmic.2021.109155

Interpretive Summary: Turkey coronavirus (TCoV) causes turkey clinical enteric disease, resulting in significant economic losses to the global turkey industry. To date, there is neither a commercial vaccine available to prevent the disease nor a TCoV disease model to evaluate a vaccine's protective efficacy. In the present study, we isolated a field strain (NC1743) of TCoV and evaluated its pathogenicity in turkey poults to establish a TCoV disease model. The results showed that the TCoV NC1743 isolate is a highly pathogenic strain, and younger turkeys are more susceptible to TCoV infection than older birds. One-day-old turkeys infected with the minimal infectious dose of TCoV NC1743 could be used as a TCoV disease model to study the disease pathogenesis. The TCoV NC1743 strain could be used as a challenge virus to evaluate the protective efficacy of a vaccine to be developed.

Technical Abstract: Turkey coronavirus (TCoV) can cause a highly contagious enteric disease in turkeys with severe economic losses in the global turkey industry. To date, no commercial vaccines are available for control of the disease. In the present study, we isolated a field strain (NC1743) of TCoV and evaluated its pathogenicity in specific-pathogen-free (SPF) turkey poults to establish a TCoV disease model. The results showed that the TCoV NC1743 isolate was pathogenic to turkey poults with a minimal infectious dose at 10E6 EID50/bird. About 50% of one-day-old SPF turkeys infected with the virus’s minimal infectious dose exhibited typical enteric disease signs and lesions from 6 days post-infection (dpi) to the end of the experiment (21 dpi). In contrast, fewer than 20% of older turkeys (1- or 2-week-old) infected with the same amount of TCoV displayed enteric disease signs, which disappeared after 15-18 dpi. Although all infected turkeys, regardless of age, shed TCoV, the older turkeys shed less virus than the younger birds, and 50% of the 2-week-old birds even cleared the virus at 21 dpi. Furthermore, the viral infection caused day-old turkeys more body-weight-gain reduction than older birds. The overall data demonstrated that the TCoV NC1743 isolate is a highly pathogenic strain and younger turkeys are more susceptible to TCoV infection than older birds. Thus, one-day-old turkeys infected with the minimal infectious dose of TCoV NC1743 could be used as a TCoV disease model to study the disease pathogenesis, and the TCoV NC1743 strain could be used as a challenge virus to evaluate a vaccine protective efficacy.