The Importance of Parasite Testing

Every year we send you a reminder about your pet’s annual physical examination, and it comes with a note:  “Please try to bring a fresh fecal (one inch of bowel movement) sample with you to this appointment (use clean containers and keep the samples cool until you arrive).” It is not a pleasant part of bringing your pet it, but it is a necessary one. Even if your pet stays indoors, he or she should be tested annually for common intestinal parasites by analyzing your pet’s stool.

What We’re Looking For

Intestinal parasites are the main targets of fecal analysis for parasite testing. These parasites include many kinds of worms, such as tapeworms, hookworms, roundworms, and whipworms. In the adult stage, these worms live in the intestinal tract and many are large enough to be seen with the naked eye but do not frequently pass in the stool. What we look for in fecal analysis are the eggs that the adult worms pass into the pet’s stool. Unfortunately, it is very rare that a fecal test can diagnose tapeworms because tapeworms pass their eggs in packets that generally hang around the pet’s rectum. There are no eggs free in the stool to be seen under the microscope. The most common type of tapeworm is spread when your pet ingests an infected flea. The best defense against tapeworms is good flea control. If you see segments that look like rice around your pet’s rectum or on the stool, you will know he or she has tapeworms.

How We Detect Parasites

There are a variety of ways we can check your pet’s stool for evidence of parasites and other problems. It is recommended by the Companion Animal Parasite Council that your pet’s stool is checked by fecal centrifugation at least once a year. This is important even for pets on medications to prevent parasites. We generally send this test out to a professional laboratory to be performed, but we perform it in our own lab if your pet presents with signs of illness and immediate results are needed. This test uses a small portion of your pet’s stool mixed in a test tube with a special solution, which is then put in a machine called a centrifuge. It is spun in a centrifuge to concentrate all the eggs (if present) in one area so that they can be identified under a microscope. If your pet is ill, we will also perform a direct smear and examine it under the microscope to look for other organisms frequently seen in this region such as Giardia.

Why It Is Important

When you see that note on your annual reminder, you may think, “I did that last year, and my pet was fine.  He still seems healthy…do I really need to bring in another sample this year?” The answer is yes! Your pet may have parasites and not show any outward signs.  It is important because the roundworms and hookworms that can live in your pet’s intestinal tract and can infect people too. By accidently ingesting roundworm eggs (one worm can produce 2 million eggs a day) from your pet or the environment, you can get the larvae traveling through your liver, lungs, and other organs. In most cases, no great harm is done, but in some cases, important tissues are damaged as the larvae lodge in nerves or even the eye of people causing blindness. When people get hookworms, the larvae enter the skin and travel about causing a rash. One type of hookworm can penetrate deeper and cause more serious damage. 

What We Recommend

To prevent problems in your pets and in your family members from intestinal parasites, do two things: bring in a stool sample at least once a year so it can be checked for worms and keep your pet on a once-monthly product that prevents intestinal parasites. Our veterinarians will recommend the best product for your pet after reviewing their medical history and lifestyle. Currently, we are recommending Sentinel or Trifexis for dogs and Revolution for cats (these products prevent fleas and heartworms, too). Sentinel, Trifexis or Revolution should be administered once a month, every month of the year, for the life of your pet.