Bacteria and viruses aren’t the only microbes that can derail your pet’s health. Tiny parasites called coccidia [cock-SID-ē-ya] can also cause big problems.

Coccidiosis [cock-sid-ē-YŌ-sis] involves severe diarrhea, sometimes with fever and vomiting. It’s especially dangerous for kittens and puppies with their undeveloped immune systems. Without treatment, animals can rapidly become dehydrated, weak and even worse.

But when treated promptly, coccidiosis usually carries a good prognosis. Most puppies and kittens are infected by contacting their mother’s stool, so pregnant animals should be tested before giving birth — even if they’re asymptomatic. Stress itself can result in coccidiosis, so relieving anxiety may help your pet physically as well as mentally.

And remember to test a new puppy or kitten for coccidia when it comes home — especially if you have other pets.