Objective—To evaluate potential risk factors for
Coccidioides infection among dogs living in a region in
which the organism is endemic (Pima and Maricopa
Design—Community-based longitudinal and crosssectional
Animals—104 healthy 4- to 6-month-old puppies (longitudinal
study) and 381 4- to 18-month-old dogs with
unknown serostatus (cross-sectional study).
Procedure—Dogs in the longitudinal study were tested
3 times at 6-month intervals for anticoccidioidal
antibodies; dogs in the cross-sectional study were
tested only once. Owners of all dogs completed a
questionnaire on potential environmental exposures.
Results—In the longitudinal study, the relative risk of
infection for dogs that were outdoors during the day
was 4.9 times the risk for dogs that were kept indoors.
Seropositive dogs in the cross-sectional study were 6.2
times as likely to have access to > 1 acre to roam as
were seronegative dogs. Logistic regression analysis
indicated that the odds of infection increased with age
(odds ratio [OR], 1.1), amount of roaming space (OR,
2.4), and walking in the desert (OR, 2.2). Walking on
sidewalks had a protective effect (OR, 0.4).
Conclusions and Clinical Relevance—Results suggest
that in regions in which the organism is endemic,
dogs that spend more time outdoors or have more
land in which to roam are at greater risk of infection
with Coccidioides spp. (J Am Vet Med Assoc 2005;