How To Identify Parasites in Animals

Sometimes it is easy to tell that an animal has parasites, because you see fleas or find worms in his stool.  Unfortunately, the majority of parasites in animals are more difficult to detect.  Owners, however, can look for unexplained weight loss, signs of illness, lethargy or unexplained itching and discomfort.  These clues to the presence of parasites indicate that it is time to see the veterinarian for some tests.

• Examine the animal’s coat for external parasites. You can see some parasites, including  fleas and ticks, with the naked eye.  Many others, however, are microscopic.  If the animal has a poor coat or is acting itchy and uncomfortable, consult a veterinarian who can perform skin scrapings for microscopic examination.


• Check the stool and the area around the anus for tapeworm eggs.  These appear as white flecks the size of rice grains.  If you see these, have a veterinarian examine the stool sample to identify the parasite and prescribe appropriate treatment.


• Look for worms in the stool or vomit of animals.  If you find any, carefully preserve them in a plastic container, and take them to a veterinarian for identification.


• Check the feces of young and sick pets for evidence of parasites.  Just because you cannot see worms or eggs does not mean they are not present.  The eggs of roundworms, lungworms and other worms and the cysts of giardia and other common parasites are microscopic, so identifying them requires a trained person with access to laboratory equipment.


• Identify parasites of the urinary tract, including Capillaria plica and Dioctophyma renale, by having a veterinarian or trained technologist examine urine samples in the laboratory.


• Test the blood of dogs and cats for heartworm infection.  Mosquitoes spread this potentially deadly parasite, and any animal not receiving a monthly preventative medication is susceptible.  The only way to detect the parasite is through blood tests.  Sometimes, microfilaria, which are infective, are present in peripheral blood.  Frequently, however, infected animals do not have microfilaria.  Fortunately, antigen and antibody tests can identify such animals.


• Examine the animal’s blood under a microscope to look for blood borne parasites such as Babesia and Ehrlichia.