Q: My dog Frankie and I were at the dog park when another dog had diarrhea and the owner did a poor job cleaning up. Now I’m worried that every time we visit this dog park, Frankie may be exposed to parasites. Is this a valid concern? A: Yes, so be sure you give him a broad-spectrum chewable or topical dewormer every month throughout the year. Since the monthly dewormers do not kill all intestinal parasites, take a fresh sample of Frankie’s stool to your veterinarian twice yearly for testing. Research shows that as many as half of fecal samples from dogs that visit dog parks are contaminated with intestinal parasites, including roundworms, hookworms, whipworms, tapeworms, and Giardia. Some parasites’ microscopic eggs survive in the environment for many years. Frankie will ingest them when he licks his feet or picks up a tennis ball—that parasite eggs stick to—when you throw …