Did you ever ask yourself why a stool sample is requested from your pet every 6-12 months if he seems to be acting normal? It’s because the six most common creepy-crawlies of the intestine can live their whole lives in there without ever being seen.

To be fair, the roundworm is occasionally seen in person: if it gets too crowded in there, a handful of worms may become displaced from their intestinal home. Roundworms that end up on the floor are usually quite lively, curling and uncurling in the unfamiliar bright and dry surroundings. Pet owners uniformly despise the sight of displaced roundworms, but most times these remain tastefully concealed inside the pet.

Hookworms are not visible without the use of a magnifying glass; most pet owners are not willing to go to these lengths. Hookworms are a little more dangerous than roundworms because they actually suck blood instead of just stealing digested food out of the gut. Although human beings can be affected by both roundworms and hookworms, neither of these is usually a problem in households that use monthly heartworm preventative.

Whipworm is a devilish little parasite that plays cat and mouse with the lab techs by laying its eggs only intermittently. On “off days”, there are no eggs under the microscope and thus no documented evidence of whipworms, even though they are inside wreaking havoc. For this reason, the doctor will sometimes prescribe worm medicine even though no parasites were detected at the lab.

Coccidiais tiny but powerful. It’s a one-celled organism, so you would never see it while casually hunting through your pet’s poop with a magnifying glass. Coccidia is particularly dangerous for youngsters, but those puppies and kittens can usually be saved if the correct diagnosis is made in time. Older animals are less likely to suffer with coccidia, but they can still become sick if they are first weakened by some other illness.

Giardia is also one cell, even tinier, and somewhat difficult to find under the microscope. It can cause major trouble for humans, particularly those that have a damaged immune system, and can be spread by healthy-looking animals. One-celled organisms are not under the jurisdiction of monthly heartworm medications; they require an exact diagnosis followed by a 7-14 day course of prescribed medicine.

The last of the Big Six is actually pretty challenging to find under a microscope, but you might catch sight of it squirming in the feces or crawling around on your pet’s anal area (no magnifying glass needed). Tapeworms are segmented individuals that live in the gut and release bits of their tail periodically. Those emancipated pieces are independent beings that seem to enjoy exploring outside the intestine. I have never met a pet owner who found this to be acceptable behavior.

Disgusting, yes, and relatively dangerous, but very, very common in cats and dogs all over the AmericanMidwest. Set yourself apart from the crowd by submitting those routine lab samples as requested by your vet.

Dr. M.S. Regan