|Susta, Leonardo - ONTARIO VETERINARY COLLEGE|
|Segovia, Diego - ONTARIO VETERINARY COLLEGE|
|Dimitrov, Kiril - CONSULTANT|
|Shittu, Ismaila - NATIONAL VETERINARY RESEARCH INSTITUTE|
|Marcano, Valerie - UNIVERSITY OF GEORGIA|
Submitted to: Veterinary Pathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/23/2017
Publication Date: 4/16/2018
Citation: Susta, L., Segovia, D., Olivier, T.L., Dimitrov, K.M., Shittu, I., Marcano, V., Miller, P.J. 2018. Newcastle disease virus infection in quail. Veterinary Pathology. 55(5):682-692. https://doi.org/10.1177/0300985818767996.
DOI: https://doi.org/10.1177/0300985818767996 Interpretive Summary: Newcastle disease causes sickness and death in Japanese quail in countries where virulent Newcastle disease viruses (NDV) are found in the environment and in domestic poultry. Unfortunately little is known about how the viruses replicate and cause disease in infected quail, nor how well the viruses are transmitted from infected birds to susceptible contact birds. Two NDV originally isolated from Japanese quail from Nigeria and two chicken strains from Israel and Pakistan were used to infect quail to evaluate the clinical disease, and the rates of mortality, shedding, and transmission. The strains that originally came from quail were shed more often, but the viruses that originated from chickens were more easily transmitted. Infections of Japanese quail with virulent strains of NDV resulted in mild to moderate clinical disease in birds directly infected, and no signs of disease in birds infected by being in contact with the infected birds. The strains adapted to quail resulted in more microscopic lesions.
Technical Abstract: Newcastle disease (ND), caused by virulent strains of Newcastle disease virus (NDV), is a devastating disease of poultry worldwide. The pathogenesis of ND in quail is poorly documented. To characterize the ability of virulent NDV strains to replicate and cause disease in quail, groups of 14 two-week-old Japanese quail (Coturnix japonica) were experimentally inoculated with 108 EID50 (embryo infectious dose 50%) units of 1 of 4 virulent NDV strains: 2 isolated from quail (N2, N23) and 2 from chickens (Israel, Pakistan). At day 2 post-infection, non-infected quail (contact group) were added to each infection group to assess the efficacy of virus transmission. Tested NDV strains showed moderate pathogenicity, with highest mortality being 28% for the N2 strain and below 10% for the others. Two N2-inoculated birds showed neurological signs, such as head tremor and ataxia. Microscopic lesions were present in N2-, Israel-, and Pakistan-inoculated birds and consisted of non-suppurative encephalitis. Contact birds showed no clinical signs or lesions. In both inoculated and contact birds, virus replication was moderate to minimal, respectively, as observed by immunohistochemistry in tissues and virus isolation from oropharyngeal and cloacal swabs. Strains originally isolated from quail resulted in higher numbers of birds shedding in the inoculation group; however, transmission appeared slightly more efficient with chicken-derived isolates. This study shows that virulent NDV strains have limited replicative potential and mild to moderate disease-inducing ability in Japanese quail.