|CARNACCINI, SILVIA - University Of Georgia|
|SANTOS, JEFFERSON - University Of Georgia|
|OBADAN, ADEBIMPE - University Of Georgia|
|RAJÃO, D.S. - University Of Georgia|
|PEREZ, DANIEL - University Of Georgia|
Submitted to: Veterinary Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/11/2019
Publication Date: 4/10/2019
Publication URL: http://handle.nal.usda.gov/10113/6343771
Citation: Carnaccini, S., Santos, J.J., Obadan, A.O., Pantin Jackwood, M.J., Suarez, D.L., Rajão, D., Perez, D.R. 2019. Age-dependent pathogenesis of clade 22.214.171.124A H5N2 HPAIV in experimentally infected broad breasted white turkeys. Veterinary Microbiology. 231:183-190. https://doi.org/10.1016/j.vetmic.2019.03.011.
Interpretive Summary: In 2015, the largest outbreak of highly pathogenic avian influenza (HPAI) in U.S. history seriously impacted the poultry industry. This study reports the pathology of H5N2 clade 126.96.36.199 HPAI virus in turkeys challenged at 6 or 16weeks of age under experimental settings. Turkeys challenged at 6 weeks of age showed little clinical signs but reached 100% mortality at 3 days post challenge (dpc). On the contrary, turkeys infected at 16 weeks of age developed signs of ataxia and lethargy and reached 100% mortality by 5 dpc. Both age groups showed significant lesions in vital organs and associated with the presence of avian influenza virus staining in multiple tissues. These findings indicate that age is a determinant factor in the progression of the disease in turkeys.
Technical Abstract: Highly pathogenic avian influenza (HPAI) is a viral disease with devastating consequences to the poultry industry as it results in high morbidity, mortality and international trade restrictions. In the present study, we characterized age-related differences in terms of pathology in commercial white broad breasted turkeys inoculated with A/turkey/Minnesota/12582/2015 (H5N2) HPAIV clade 188.8.131.52A, a virus from the largest HPAI poultry outbreak that affected the Unites States in 2014–2015. Turkeys infected at 6-weeks of age showed inapparent to little clinical signs with rapid disease progression, reaching 100% mortality at 3 days post infection (dpi). In contrast, turkeys infected at 16-weeks of age developed ataxia and lethargy and reached 100% mortality by 5 dpi. Infection in the 6-weeks old turkeys resulted in peracute lesions consistent of extensive hemorrhages, edema and necrosis, but inflammation was not prominent. In the 16-weeks old turkeys, necrosis and hemorrhages in tissues were accompanied by a more prominent subacute inflammatory infiltrate. Both age groups showed presence of avian influenza virus (AIV) nucleoprotein (NP) in multiple cell types including neurons, glial cells, ependymal cells, respiratory epithelial cells, air capillary epithelium and pulmonary macrophages, cardiac myocytes, smooth muscle fibers, pancreatic acini and ductal cells. Cells of the vascular walls stained strongly positive for viral antigens, but no positivity was found in the endothelial cells of any organs. These findings indicate that age is a determinant factor in the progression of the disease and delay of mortality during infection with the H5N2 clade 184.108.40.206A HPAI virus in naïve white broad breasted turkeys.