Experimental reproduction of a spiking mortality syndrome of turkeys

Two-day-old turkey poults were inoculated with either a chicken embryo homogenate used previously to produce spiking mortality syndrome in chickens (the "Oakwood Agent") or an intestine-pancreas homogenate collected from field turkeys with the syndrome known as spiking mortality of turkeys. Twelve days postinoculation, the mean plasma insulinlike growth factor-1 (IGF-1) level and mean body weights were significantly depressed, and the mean plasma growth hormone level was significantly elevated, in the poults receiving the turkey-derived homogenate (P < or = 0.0003), as was previously reported in chickens with spiking mortality syndrome. The depression in plasma IGF-1 levels may explain the runting seen in poults that survive spiking mortality of turkeys in the field. Following a 4-hr fast and a brief cool water spraying, poults exhibited clinical signs indistinguishable from those of chicks with spiking mortality syndrome. However, plasma glucose levels in the affected poults were within the normal range, unlike chickens with spiking mortality syndrome. Immunohistochemistry on formalin-fixed intestines, ceca, and bursae produced positive staining using an arenavirus antibody in epithelial cells of poults inoculated with the turkey homogenate and those inoculated with the Oakwood Agent. Tissues of uninoculated controls were negative. Poults inoculated with the Oakwood Agent did not show noticeable disease.