The Classic Comprehensive Handbook of Cat Care: INTERNAL AND EXTERNAL PARASITES

Parasites are creatures that at some point during their life cycle are dependent on a host (e.g., your cat). Not all parasites are harmful. In fact, in most well-cared-for small animals, owners overrate parasites as causes of illness. Under specific circumstances, certain parasites do cause disease; however, don’t assume that because your cat is sick he or she has worms or that because he or she is scratching fleas must be present.


If you think your cat has a parasite problem, look for the signs in the Index of Signs. (Remember, though, not all animals with parasite infections show signs.) If you find the signs, turn to the appropriate pages and use the information there to help you decide whether or not you need to consult a veterinarian. In most cases of internal parasite infection you will need professional help (see the following pages). Many times you can correct an external parasite problem yourself.

If you don’t think your cat has a parasite problem, it’s a good idea to read or skim this section anyway to complete your knowledge of preventive medicine. The information is included here in the preventive medicine pages because the key to a successful fight against parasites is good prevention and control, which require good daily care. If you fail in your general daily care to take into account the life cycle of certain parasites, you may continue to have a problem even though you have administered treatment against the parasite to your cat. Learning about the different parasites discussed below will help you provide a healthy environment for your cat, thus preventing serious infection and reinfection of your pet as well as preventing human infection with certain parasites.

Internal parasites: Protozoans, flukes, typeworms, and the following roundworms: ascarids, hookworms, whipworms, threadworms, stomach worms, eyeworms, lungworms, heartworms. External parasites: Fleas, ticks, lice, mites, flies.

Internal Parasites (Endoparasites) The endoparasites consist of protozoa, trematodes (flukes), cestodes (typeworms), and nematodes (roundworms). For the most part, the adults of these parasites live in the intestines. They may be present with or without causing illness, and you may or may not see them in your cat’s stools. Only if your cat is infected with one of the larger forms may you be able actually to see the parasites.

If you think your cat has intestinal parasites but can’t be sure because you have not seen them or if you have a new cat, take a fecal sample to your veterinarian. (A tablespoonful is plenty.) It should be as fresh as possible, in any case not more than twenty-four hours old even if kept under refrigeration. Veterinarians use special procedures to separate the parasites and/or their eggs from the stool and look for evidence of infection microscopically. A variety of drugs is used to treat internal parasites. Most can be administered orally by you at home. The products mentioned here are generally designated by their chemical generic name.