Degree Type


Date of Award


Degree Name

Doctor of Philosophy


Veterinary Microbiology and Preventive Medicine


This study consisted of 5 parts: (1) the determination that turkey embryos can be infected with hemorrhagic enteritis virus (HEV), (2) an evaluation of the age-dependence of HEV infection in the embryo, (3 and 4) an evaluation of the relationship between bursal and spleen infection with HEV in the embryo and poult, and (5) the titration of infectious virus produced in the bursa and spleen of HEV-infected embryos;Infection of the turkey embryo in the latter stages of embryonation with HEV was established by detecting HEV antigen in the spleen and bursal cells with the indirect fluorescent antibody (IFA) test and the agar gel diffusion precipitin (AGDP) test. The IFA test proved to be more sensitive than the AGDP test;A dependence on the stage of maturation rather than on incubation time for HEV infection was substantiated when 17 and 22-day-old embryos were inoculated via the allantoic cavity. Infection was detected in the 17-day-old inoculated group 8 days post inoculation or day 25 of embryonation, and in the 22-day-old inoculated group 2 days post inoculation or day 24 of embryonation;It was shown that bursal infection precedes spleen infection by 2 days in the embryo even though both tissues were exposed simultaneously by intraveneous inoculation to HEV, thus suggesting a dependency of spleen infection on prior bursal infection. In newly hatched poults inoculated via the intracardiac route, however, infection of the bursa did not occur prior to infection of the spleen. Thus at this stage of maturation, the spleen possessed cells capable of viral infection whose origin might be the bursa;Very low titers of infectious HEV were detected in the bursa and spleen of infected embryos and poults. It was not established if these titers represented embryo-produced virus, residual inoculated virus, or a combination of both.



Digital Repository @ Iowa State University,

Copyright Owner

Rebecca L. Wallskog Hyde



Proquest ID


File Format


File Size

74 pages