First Advisor

Luis Ruedas

Date of Award


Document Type


Degree Name

Bachelor of Science (B.S.) in Biology and University Honors




Zoonoses, Homeless persons -- Health and hygiene -- Oregon -- Portland, Dogs as carriers of disease, Parasitic diseases -- Transmission, Veterinarian and client -- Oregon -- Portland




Veterinarians are the front-line in the world of pet-health and zoonoses which means they are also at the front-line of human health and have an important role of educating clients on behaviors that would both reduce the risk of human and pet contracting a disease. In this study we collected 85 stool samples in Portland OR, USA and examined these by centrifugal fecal flotation, direct smears and for a small number (n=15) ELISA snap-tests. Parasitic prevalence was found to be 27.1% total including 2.4% Ancyclostoma Sp., 4.7% Cryptosporidium Sp., 7.1% Cystoisopora Sp., 9.4% Taenia Sp., 2.4% Giardia Sp., and 2.4% Toxocara Sp. This study was carried out within a homeless/low-income population using a charitable clinic (Portland Animal Welfare Team) as the sampling site. A questionnaire was used in tandem with the sampling to survey owner & animal demographics, risk behaviors, owner risk perception and owner education surrounding zoonoses & deworming protocols. Dog park use had a negative correlation with positive results suggesting exposure elsewhere despite dog park environmental contamination. Socialization with dogs, living environment (unstable and transitional), and pet gender (male) all lead to increased disease prevalence. Notably, those who deworm their pet on a symptomatic basis had similar prevalence to those who never deworm, deworming as little as annually quartered the risk to the dog. Also this study found over 20% of asymptomatic patients to be positive, over double the expected (5-10%). Lastly, in the education section the majority of the population surveyed (67.2%) had little knowledge of zoonoses and potential animal to human transmission. Veterinarians had spoken to most clients about deworming frequencies, but not zoonoses a gap which needs to be addressed. Veterinarians have a duty to educate clients on the importance of regular screening and deworming regardless of symptoms due to zoonotic potential of many parasites.


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