Surveillance of selected zoonotic diseases in the Keokuk County and my experience with IRB
approval
Melkova R1, Donham JK2, Gahan TF3, Gray GC4, Gilchrist MJR3.
1
Institute of Preventive and Clinical Medicine, Bratislava, Slovak Republic; 2Department of Preventive
Medicine and Environmental Health, University of Iowa. Iowa City, USA; 3 The Iowa University
Hygienic Laboratory, Iowa City, USA; 4 Department of Epidemiology College of Public Health,
University of Iowa, Iowa City, USA;
Context: Since the data on possible source of selected zoonotic diseases in Iowa exist, we focused on the
prevalence in human population with an increased risk for environmental exposure.
Objective: Serological testing of human sera samples for presence of IgM and/or IgG antibodies against
Ehrlichia chaffeensis, Rickettsia rickettsii, R. typhi, Borrelia burgdorferi and Leptospirosa biflexa.
Design, setting, and participants: We surveyed presence of antibody against the selected infectious
agents in sera of 50 randomly selected adult men (18+) from 195 adult farmers or rural men from the
Keokuk County of Iowa State. Sera were obtained from blood drown in 2nd round (1999-2001) of ongoing
Keokuk County Rural Health Study (KCRHS). 2nd round sera with increased level of specific antibodies
were simultaneously compared with corresponding sera from 1st round (1994-1998) of KCRHS.
Results:
Sera of two subjects from both rounds of KCRHS had increased level of IgG against E. chaffeensis. Six
subjects’ sera from 2nd round showed presence of antibodies to R. rickettsii or R. typhi in low titer. The
only one subject’s sera from both rounds showed presence of the antibodies to R. typhi. Five subjects’
sera from 2nd round were positive (3) or equivocal (2) to B. burgdorferi in preliminary test (ELFA VidasLYT) but negative in additional test (Western blot MarDx Marblot system). One subject’s sera from both
rounds of KCRHS showed presence of IgM to L. biflexa antigens.
Conclusions:
Survey in population with higher risk to zoonotic diseases showed the presence of E. chaffeensis
pathogen in Keokuk County. However some tested sera showed low level of the antibodies against R.
typhi, L. biflexa, B. burgdorferi. None of the tested sera showed positive reaction to more then one agents.
Ethical Issue:
Regarding the ethical issues the pilot study had to be approved first by KCRHS Executive Committee in
order to get permission to use sera and data and second by Institutional Review Board (IRB) as it was
a new project on human subjects. Participants of KCRHS had signed informed consent document of
KCRHS with an anchored note about possible future use of their sera for serology tests. It was not
necessary to contact the study subjects again. Subjects’ data were collected and stored within a KCRHS
data set. We used the same KCRHS ID labeling systems of the subjects. In the study proposal we planed
to use materials (sera) and data that had been collected in existing study (KCRHS) with the approved
protocol and the informed consent. The study was also supposed to be a student-training project. Due to
this facts and with KCRHS Executive Committee support we applied to IRB under Expedited Review
Categories which allow to obtain approval in shorter time. After three days from application submission
we obtained IRB approval of the project.