Canine Parvovirus Infection and Long-Term Health

Canine parvovirus (CPV) infections cause serious and acute gastrointestinal (GI) disease, particularly in puppies. By attacking the rapidly dividing intestinal crypt epithelium and destroying the intestinal barrier, CPV causes hemorrhagic diarrhea and may predispose dogs to chronic immunologic diseases. CPV also affects myocardial cells, which can lead to acute heart failure and sudden death in young puppies.

CPV treatment is aggressive and often involves intravenous broad-spectrum antibiotic therapy. However, as reported in human studies, antibiotic therapy early in life can increase the risk of chronic allergic and GI diseases.

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To date, little information has been available on the long-term health effects of CPV infection. The authors of a recent PLoS ONE report noted that “this knowledge would be important to establish a long-term prognosis” of CPV.

Data Collection

The investigators recruited dogs presenting with clinical CPV and dogs without CPV (control dogs); control dogs had not received prior antibiotic therapy.

Selected laboratory (ie, white blood cell count) and clinical parameters (ie, blood in feces or vomit) were evaluated to determine a correlation between acute CPV infection and chronic GI disease later in life.

All dog owners completed a 5-part questionnaire:

• Part 1: general information (ie, parasite prevention)
• Part 2: chronic GI problems, based on the Canine Inflammatory Bowel Disease Activity Index (CIBDAI)
• Part 3: chronic skin disease
• Part 4: cardiac disease
• Part 5: other chronic disease

The CIBDAI measures GI disease activity parameters, including appetite and stool frequency. Scores indicate disease severity, ranging from clinically insignificant (0—3) to severe inflammatory bowel disease (> 9).

Results

General Information

The investigators collected 138 questionnaires from the owners of dogs with (n=71) and without (n=67) CPV. At presentation, compared with control dogs, dogs with CPV were significantly younger (median age, 12 vs. 27 weeks) and more frequently received regular endoparasite prevention (94% vs. 79%).

All dogs with CPV presented with acute diarrhea and most had vomiting; the diarrhea or vomiting was hemorrhagic in some dogs. All but 5 dogs with CPV received antibiotic therapy. Notably, the diarrhea improved with dietary changes. Most control dogs presented for wellness exams and vaccination.

Long-Term Health Effects

Chronic GI problems were significantly more frequent in dogs with CPV than in control dogs (42% vs. 12%), indicating “a higher risk of chronic GI problems following CPV infection,” the investigators wrote. Similarly, CIBDAI scores were higher in dogs with CPV than in control dogs, reflecting greater disease severity. No correlation between age of CPV infection and prevalence of chronic GI disease later in life was observed.

The investigators proposed 3 mechanisms to explain the higher risk of chronic GI disease following CPV infection:

• Shortened or obliterated villi, leading to osmotic diarrhea
• Epithelial barrier destruction and altered interaction between the mucosa and resident microbes
• A breakdown in oral tolerance, resulting in increased immune system responsiveness to ingested protein antigens

Dogs with CPV did not have a higher risk of cardiac or skin disease. In addition, no laboratory or clinical parameters were significantly associated with increased risk of chronic GI disease later in life.

Moving Forward

Given the study’s limitations, including reliance on subjective owner assessments, the observed increased risk of chronic GI disease following CPV infection is not unequivocal. Future studies will be needed to “differentiate between the influences of CPV infection itself, its treatment, or any other severe acute gastrointestinal insult acting as a trigger agent for chronic gastrointestinal problems,” the authors concluded.

Dr. Pendergrass received her doctor of veterinary medicine degree from the Virginia-Maryland College of Veterinary Medicine. Following veterinary school, she completed a postdoctoral fellowship at Emory University’s Yerkes National Primate Research Center. Dr. Pendergrass is the founder and owner of JPen Communications, a medical communications company.