Feline Parasites You Might Not Know About
Stephen Sheldon, D.V.M.

Dorland's Medical Dictionary defines a parasite as "a plant or animal which lives upon or within another living organism at whose expense it obtains some advantage". Insert your white collar professional joke here! We all know about the 'big 3' parasites that infect our kitties: hookworms, roundworms, and tapeworms, but, believe it or not all parasites are NOT worms. Organisms such as Hemobartonella, Coccidia, Giardia, and even Heartworms are all lesser known parasites that deserve some attention.

Feline Hemobartonellosis or 'hemobart' as the common name (thank goodness) is also known as Feline Infectious Anemia (FIA) and is an important cat disease. It is a rickettsial organism which is kind of in between a bacteria and a virus on the evolutionary chain. It has been around since 1942 but much about it still remains a mystery. It can be a primary disease itself or a secondary invader riding in on the coattails of such famous diseases as Feline Leukemia/Aids Viruses and autoimmune diseases.

Hemobart causes a wide range of clinical signs but most of the damage comes from destruction of red blood cells and anemia. We call these severely anemic cats 'cool-aid cats' because their thin blood resembles the fruity drink and not the viscous life sustaining stuff we call blood. Any 'cool-aid cat' is automatically a suspect for Hemobart. These anemias are often life-threatening and these cats frequently need a transfusion.

The disease can be difficult to diagnose because the only way to know your dealing with Hemobart is to see the bugger on the surface of a red blood cell. It sounds simple enough but it only occurs intermittently so you need to look at blood cells every 18 to 36 hours. Hemobart is transmitted in one of 3 postulated ways (again we are not positive): 1. through arthropods like fleas and ticks, 2. through cat bites in which blood is involved (urine and saliva are not considered infectious) and 3. from mother to offspring (again we don't know if it is in the placenta, during birth or by nursing).

Treatment is not a complex thing. First we provide supportive care including rehydration and blood transfusions if needed. Then antibiotics like doxycycline or oxy/tetracycline are used. These can cause fever and anorexia in cats but most tolerate them well; if they don't, there are other effective antibiotics. Most veterinarians also use corticosteroids although the timing as to their administration is controversial. We use it right away if the infection is deemed life threatening. Hemobart can be treated but often we have not completely eliminated it from the blood and many cats remain carriers. The prognosis is much better if Hemobart is NOT associated with Feline Leukemia/Aids.

Giardia is a protozoal organism found in the intestinal tract of cats; most often it affects young cats. This suggests an acquired immunity as cats age. The transmission of Giardia is fecal-oral thus it is more of a problem in catteries and other areas where cats are

congregated. Some species of Giardia are thought to be transmittable to people (ie. zoonotic) but the jury is still out.

Not all cats with the parasite show clinical symptoms. Diarrhea is the most common with the feces having a characteristic look and smell. The feces are usually pale, soft and often blood tinged. The diarrhea can cause dehydration and weight loss but rarely causes death. Giardia is diagnosed by seeing the parasite on a fecal smear; this is different from a typical fecal float exam although it can be detected that way too. Newer more expensive diagnostic tests kits are available but we don't use them as often because the disease is easy to treat with an inexpensive medicine.

Metronidazole or flagyl is our first choice drug; quinacrine or atabrine is also used. Both are bitter and can cause frothing. Panacur or fenbendazole given 5 consecutive days will also work. These drugs kill the active form of Giardia, the trophozoites, but may not eliminate the dormant state or cysts, so reoccurrences can occur.

Coccidiosis is another common intestinal protozoal disease. It is caused by organisms in the isospora (most common), toxoplasma, sarcocyctis, or cryptosporidim genus. Most of our discussion will center around isospora as it is the most common. Other Pet Tribune articles have discussed toxoplasma.

Coccidia has an interesting life cycle. Most of what you need to know is that it is a fecal-oral transmission; however mice, cattle, sheep and other herbivores act as an intermediate host. The oocysts of cryptosporidium parvum can be transmitted to man; immunocompromised people are at greatest risk.

Whether or not the more common isospora species cause disease in cats is questionable, and even though some researchers say it is a self-limiting disease I don't know any veterinarians who do not treat it when found during a fecal exam. Clinical signs include diarrhea, vomiting, and abdominal pain. The disease is easily treated with sulfonamide type antibiotics. Some humane society type organizations around the country will condemn cats testing positive for coccidia due to it's possible zoonotic potential (ie. if it is a toxoplasma or cyptosporidium species). Most veterinarians feel this is extreme, especially since it is easy to distinguish the different species under a microscope.

I hope you all have learned a little about some different parasites of cats. Feline Heartworm Disease is another parasite that is little known to the cat loving population and we'll research it for you thoroughly in the next issue. It is on the rise in S. Florida and it is now known that the cat is a definitive host for the parasite and not an atypical host as has been long thought. See you next month!