Coccidiosis usually targets young kittens shortly after
weaning, although adult cats can be affected. The disease is highly contagious.
Immunity following recovery from infection is short-lived. Cats who recover
often become carriers and shed adult oocysts in their feces.
There are several species of coccidia. Only Cystoisospora (formerly known as
Isospora) felis is directly transmitted by fecal contamination from cat to cat.
Other species use birds and animals as intermediate transport hosts. These
species complete their life cycle when the transport host is eaten by the cat.
Kittens acquire Cystoisospora felis from mothers who are carriers.
The feline immunodeficiency virus
(FIV), first discovered in a northern California cattery in 1986, is a major
cause of chronic immunodeficiency in cats. FIV is a retrovirus
belonging to the lentivirus family. It is related to the HIV virus in humans
(the virus that causes AIDS). However, these two viruses are species-specific.
HIV does not produce disease in cats and FIV does not produce disease in
FIV infection is believed to be transmitted by cat bites, such as the one
Five to seven days after ingesting the oocysts, infective cysts appear in
the feces. Much of the life cycle takes place in the cells lining the small
intestines. Diarrhea is the most common sign of infection. The
feces are mucuslike and tinged with blood. In severe cases, a bloody diarrhea
may develop. These cases are complicated by weakness, dehydration, and anemia.
Coccidia can be found in the stools of kittens without causing problems,
until some stress factor, such as overcrowding, malnutrition, weaning problems,
an outbreak of ascarids, or shipping reduces their resistance. Normal fecal
flotations will pick up these parasites.
Treatment: Offer a bland diet and encourage fluid intake. A severely
dehydrated or anemic cat may need to be hospitalized for fluid replacement or
blood transfusion. Kittens are more likely to require intensive care than adult
Supportive treatment is important, since in most cases the acute phase of
the illness lasts about ten days and the cat then recovers. Sulfonamides and
nitrofurazone are the antibiotics of choice.
Known carriers should be isolated and treated. Cat quarters and runs should
be washed daily with disinfectants and boiling water to destroy infective
This disease is caused by a protozoan of the Giardia species. Cats have
their own species-specific version of Giardia. Cats acquire the infection by
drinking water from streams and other sources that are contaminated with
Most infections in adult cats are subclinical. Young cats and kittens can
develop a diarrhea syndrome characterized by the passage of large volumes of
foul-smelling, watery stools. The diarrhea maybe acute or chronic, intermittent
or persistent, and may be accompanied by weight loss.
Diagnosis is made by finding the protozoan or its characteristics cysts in
saline smears of fresh stool. Smears from rectal swabs are satisfactory. A
negative smear does not exclude giardia, as cysts are shed only intermittently.
Three negative fecal smears collected at least two days apart should be
obtained before the diagnosis is excluded. Serology tests (ELISA and IFA) are
Cats do not seem to develop an immunity to giardiasis, so prevention
includes cleaning up areas of stagnant water where the protozoa may flourish
and/or keeping cats away from those areas. The indoor environment should be
thoroughly cleaned as well.
Treatment: Giardiasis responds well to Flagyl (metronidazole). Because
Flagyl causes developmental malformations in the fetus, it should not be
administered to pregnant queens. Metronidazole also prevents bacterial
overgrowth and may influence existing immune disorders in the intestines. Other
effective drugs are available, such as febendazole. There is now a vaccine
available for giardiasis, but it is rarely recommended because the disease is
usually mild and responds well to treatment.
WebMD Veterinary Reference from "Cat Owner's Home Veterinary Handbook"