Numerous factors influence the presence of diarrhea in dogs housed together, including primary gastrointestinal pathogens, stress, change in diet, and predisposing disease conditions. This study evaluated the association between infectious pathogens and diarrhea in dogs at an animal shelter. A 1:1 matched, case-control study design was used. The first nondiarrheic fecal sample found near the cage was collected. Fecal samples from 60 case dogs and 60 control dogs were evaluated by several techniques. Intestinal parasitism was found by fecal flotation in 33.3% of the case dogs and in 16.1% of the controls. Parasites found included Ancylostoma species, Toxocara canis, Trichuris vulpis, and Giardia lamblia. Cryptosporidium was detected in both case and control dogs. Since some of these parasites have zoonotic potential and dogs shed parasites regardless of whether they have diarrhea, empiric deworming is an important step to reduce environmental contamination. Among microbes, Salmonella enterica and Brachyspira species were not common, but canine coronavirus and Helicobacter species were often present in both groups of dogs. Only 1 dog had parvovirus, but this was not unexpected as severely ill dogs are removed from the general population.

Commentary: This interesting research represents a novel approach to investigating the epidemiology of several infectious agents and parasites capable of causing or contributing to diarrhea in dogs housed under high-density kennel (animal shelter) conditions. Results of the study corroborate those obtained in several previous studies. Certain results are important and worthy of restating. The authors found, as have others, that the prevalence of intestinal parasites (helminths and protozoa) as a group was substantially higher in dogs with diarrhea than in those without diarrhea. Also, Toxocara canis, the most important of the potentially zoonotic helminths, was the most common parasite in dogs, regardless of whether they had diarrhea. This result emphasizes the need to conduct timely fecal examinations in dogs, even if parasites are not suspected. The authors also showed that use of a combination of fecal examination procedures, such as centrifugal flotation and fecal immunologic assays, increases the likelihood of detecting Giardia infections. In addition, the methodologies of these studies, such as geographic information systems for tracking the distribution of infectious agents in a population, may aid shelter personnel in identifying shelter-specific problems and help in the development of diarrhea management options.

Epidemiologic evaluation of diarrhea in dogs in an animal shelter. Sokolow SH, Rand C, Marks SL, et al. AM J VET RES 66:1018-1024, 2005.