OAHN Poultry Research Project: Identification of Transmissible Viral Proventriculitis (TVP)


Project Lead:      Dr. Marina Brash

Project Co-Lead: Dr. Csaba Varga





OAHN Poultry Research Project 2018-2019: Identification of Transmissible Viral Proventriculitis (TVP)

Over the quarter Q3, 2019(May-July),  there were increasing reports of proventricular dilation and thickened proventriculi on farm with no breed specificity. There were also sporadic reports of proventricular dilation resulting in delayed emptying following normal feed withdrawal practices causing increased condemnations at processing from contamination. In addition, field practitioners have reported seeing chickens with pendulous crops and chickens regurgitating feed. The Animal Health Lab has historically tracked proventricular lesions and the typical mild-to-moderate proliferative lesions with and without predominantly mild-to-moderate nonsuppurative lesions resembling Transmissible Viral Proventriculitis [(TVP, caused by a birnavirus, chicken proventricular necrosis virus (CPNV)] were seen again this quarter, however in addition, more proventricular ductal dilation was also noted. Samples of affected proventriculi from affected flocks on farm and at processing, were sent for immunohistochemical staining (IHC) for CPNV. Results of this initial screening show that only 3 of 18 cases of affected proventriculi were positive for CPNV. Cases positive on IHC were from young broilers with clinical presentation of runting and stunting showing severe proventriculitis on pathology examination. No samples of dilated proventriculi collected at processing were positive. One case with lesions similar to the other three cases was negative for CPNV however the birds were slightly older. In conclusion, initial testing does indicates that TVP is in Ontario broilers but to a limited degree. Further testing is warranted in order to determine the prevalence and the possible role that TVP may play in proventricular dilation. The AHL has been able to acquire CPNV antibody so will be able to conduct IHC TVP testing in-house in the near future and this will allow us to acquire more information regarding the prevalence of this particular condition. Further discussions with the poultry industry are required to determine if the issue is of significant concern, and to discuss next steps forward to investigate proventricular dilation.