58 CARDIAC 
disease and a familial mode of inheritance. 
The authors2i'22 have demonstrated a re- 
duction in death losses of poults during the 
acute phase of the disease with immunosup- 
pressive levels of cortisone. The improved 
survival rate of susceptible turkeys was not ac- 
companied by any morphological changes upon 
examination by both light and electron micro- 
scopy. It was postulated that the mechanism of 
injury, if it is related to the virus-like particles, 
may not be due to their presence in the cell, but 
to some immunologic process. The suggestion 
was made that cortisone may influence the im- 
mune response more than the inflammatory re- 
action. 
SUMMARY 
Turkey Round Heart Disease appears to have 
a familial mode of inheritance. 
The RH male/female sex death ratio during 
the chronic phase is approximately 2:1. 
Fifty percent of the RH turkeys with RH at 
four weeks of age will spontaneously "recover" 
by 13 weeks of age. 
Approximately 30% of four to five week old 
RH turkeys have cardiac murmurs consistent 
with mitral insufficiency. 
Turkey round heart disease is an appropriate 
model for the study of cardiomyopathy. 
ACKNOWLEDGMENTS 
We want to thank Mr. Walter Hunsaker, Ca- 
nadian Department of Agriculture, Ottawa, On- 
tario, Canada, for contributing hatching eggs 
from which Flock 2 was originated, and Dr. 
B. S. Pomeroy, University of Minnesota, for do- 
nating turkeys for Flock 1 foundation stock. We 
also wish to acknowledge the excellent turkey 
care provided by Mr. Carl W. Edborg, III, and 
the able assistance of Mr. Virgil Voigt, Mr. 
Bruce Hultgren, and Mr. James Reiser. 
This research was supported in part by the 
Minnesota Turkey Growers' Association, the 
Dwan Family Fund, and the Minnesota Heart 
Association. 
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