Hemorrhagic vasculopathy is a noninfectious cardiovascular disorder of rapidly growing male turkeys, although it occasionally affects other species. The predominant clinical sign is sudden death. Diagnosis is based on history and on finding typical lesions at necropsy. There is no specific treatment; however, decreasing stress and limiting feed intake during the rapid growth phase may decrease incidence.
Death from acute internal hemorrhage is common in commercial male turkeys. Distinct clinical manifestations include sudden death syndrome of turkeys associated with perirenal hemorrhage and aortic rupture.
Etiology and Pathogenesis of Hemorrhagic Vasculopathy in Turkeys
Sudden death syndrome of turkeys associated with perirenal hemorrhage and aortic rupture are two forms of hemorrhagic vasculopathy in turkeys.
Sudden Death Syndrome of Turkeys Associated With Perirenal Hemorrhage (SDPH)
Sudden death syndrome of turkeys associated with perirenal hemorrhage (SDPH) is a noninfectious cardiovascular disorder usually affecting rapidly growing male turkeys 8–19 weeks old. SDPH is characterized by sudden death, perirenal hemorrhage, and hypertrophic cardiomyopathy. Mortality rate is usually 0.5%–2% but can be higher; birds often die without premonitory clinical signs.
Healthy, rapidly growing flocks are most likely to be affected.
The pathogenesis of SDPH is unknown but is apparently unrelated to pulmonary function or pulmonary hypertension. Inadequate or inappropriate cardiac response to exercise, resulting in systemic hypotension, vasodilation, and ventricular arrhythmia, likely contributes to death.
Acute congestive heart failure secondary to cardiac hypertrophy is often associated with SDPH. Renal hemorrhage likely results from severe passive congestion and dissection of blood through the fragile renal parenchyma; acute blood loss is not always the primary cause of death because the extent of perirenal hemorrhage is variable and often mild. A physical rupture in the renal artery or adjacent vessels is usually not identified.
Aortic Rupture
Aortic rupture, or dissecting aneurysm, also causes sudden, unexpected death in otherwise healthy, rapidly growing male turkeys.
A genetic predisposition for aortic rupture is strongly suspected because the disease occurs more often in particular commercial turkey breeds. The condition has also been described in chickens, ostriches, and waterfowl but is considered a classic disease of turkeys. Death from aortic rupture results from massive, acute hemorrhage into the coelom. Losses in affected flocks are usually 1%–2% but can reach 10%.
Precipitating factors associated with aortic rupture include copper deficiency, systemic hypertension, hormonal influences, dietary factors (eg, zinc deficiency), administration of certain pharmaceuticals(eg, diethylstilbestrol, beta-aminopropionitrile, hydralazine), atherosclerosis, and certain management practices.
Clinical Signs of Hemorrhagic Vasculopathy in Turkeys
Sudden death syndrome of turkeys associated with perirenal hemorrhage and aortic rupture are similar noninfectious cardiovascular disorders usually affecting rapidly growing male turkeys 8–19 weeks old. The disorders are characterized by sudden death and acute internal blood loss (see blood from mouth, aortic rupture image).
Courtesy of Dr. Robert Porter.
Birds are usually in excellent body condition and often die without premonitory signs.
Lesions
Sudden death syndrome of turkeys associated with perirenal hemorrhage is often associated with acute congestive heart failure secondary to cardiac enlargement/hypertrophy. Microscopic changes of SDPH are consistent with gross findings and include pulmonary congestion and edema with renal perivenous and parenchymal hemorrhage (see SDPH image).
Affected turkeys have intimal vacuolation and medial hyperplasia of arteries and arterioles in multiple organs, particularly kidney, spleen, and lung; however, similar lesions can be observed to a lesser extent in tissues of healthy turkeys.
Courtesy of Dr. Robert Porter.
Aortic rupture, often visible as a laceration near the branch of the cranial mesenteric artery, manifests microscopically as intimal thickening or large, sclerotic plaques accompanied by fragmentation of elastic fibers and degenerative changes of smooth muscle cells at the site of the gross lesion. The aortic tunica intima and media are thrown into deep folds and separated from the tunica adventitia. Lipid accumulation in the thickened intima and in the fibrous plaques can be identified by special stains. Fibers of the tunica media may show degeneration and infiltration with heterophils and macrophages. (See aortic rupture images: blood in coelomic cavity, blood clots from aortic rupture, and rent in aorta.)
Courtesy of Dr. Robert Porter.
Courtesy of Dr. Robert Porter.
Courtesy of Dr. Jean Sander.
Diagnosis of Hemorrhagic Vasculopathy in Turkeys
History
Typical gross lesions
Sudden death syndrome of turkeys associated with perirenal hemorrhage and aortic rupture can occur simultaneously in a flock. Diagnoses of SDPH and aortic rupture are based on history, typical gross lesions, and absence of causative infectious agents.
SDPH can occasionally include extensive abdominal hemorrhage that resembles that seen with aortic rupture. However, SDPH is usually accompanied by cardiac enlargement or hypertrophy, whereas a distinct aortic tear can usually be detected in turkeys with aortic rupture.
Treatment of Hemorrhagic Vasculopathy in Turkeys
No specific treatment
Prevent by decreasing stress and limiting feed intake
Although there is no specific treatment for sudden death syndrome of turkeys associated with perirenal hemorrhage, factors that decrease growth rate and activity also tend to decrease SDPH.
Reserpine (0.5 ppm [0.5 mcg/g]) administration decreases SDPH; however, treatment with aspirin and increased calcium has no effect. Reserpine is no longer listed in the Feed Additive Compendium as approved for use in feed for turkeys, so it cannot be used in commercial flocks.
In addition to drug treatment, several management changes may be instituted to lessen the likelihood of SDPH. For example, increased room temperature and step up/step down lighting programs can decrease SDPH. Minimizing activities that increase cardiovascular stress (eg, moving birds, tilling litter, noise), especially when birds are 7–15 weeks old, also may help decrease SDPH. Conversely, lower ambient temperatures (13°C [55°F]), intermittent lighting, and unclipped toes increase mortality rates from SDPH.
For aortic rupture, as with SDPH, there is no specific recommended treatment.
To decrease incidence of aortic rupture, rations can be supplemented with copper at 125–250 ppm (125–250 mcg/g) from at least 4 weeks old until market; however, this is not a dependable preventive measure. Limiting overall feed or protein intake during the growth period to slow growth rate might decrease the occurrence of aortic rupture. As with SDPH, minimizing activities that increase cardiovascular stress may also help lessen incidence of aortic rupture.
Key Points
Sudden death syndrome of turkeys associated with perirenal hemorrhage and aortic rupture are two forms of a fatal cardiovascular syndrome in rapidly growing male turkeys.
Diagnosis is based on history and finding characteristic gross lesions in the absence of causative infectious agents.
There is no effective treatment; however, ensuring adequate dietary copper, minimizing stress, and limiting feed intake during the rapid growth phase (from 7–15 weeks) may decrease the incidence.
For More Information
Shivaprasad HL. Miscellaneous diseases. In: Boulianne M, ed. Barger M, Dorko N, French JD, et al, associate eds. Avian Disease Manual. 8th ed. American Association of Avian Pathologists; 2019:157-180.
Crespo R. Developmental, metabolic, and other noninfectious disorders. In Swayne DE, ed. Boulianne M, Logue CM, McDougald LR, Nair V, Suarez DL, associate eds. Diseases of Poultry. 14th ed. Wiley Blackwell; 2020:1286-1329.
Stenzel T, Tykałowski B, Koncicki A. Cardiovascular system diseases in turkeys. Pol J Vet Sci. 2008;11(3):245-250.
