by Race Foster, DVM
and Marty Smith, DVM
Drs. Foster & Smith, Inc.
What are coccidia?
Coccidia are small
protozoa's (one-celled organisms) that multiply in the intestinal tracts of
dogs and cats, most commonly in kittens and puppies less than six months of
age, in adult animals whose immune system is suppressed or in animals who
are stressed in other ways (e.g., change in ownership, other disease
In cats and dogs, most
coccidia are of the genus called Isospora. Isospora canis and I. ohioensis
are the species most often encountered in dogs; I. felis and I. rivolta are
the most common in cats. Regardless of which species is present we generally
refer to the disease as coccidiosis. As a puppy or kitten ages it tends to
develop a natural immunity to the effects of coccidia. As an adult it may
carry coccidia in its intestines, shed the cyst in the feces, but experience
no ill effects.
How are coccidia
A puppy or kitten is
not born with the coccidia organisms in its intestine. However, once born,
the puppy or kitten is frequently exposed to its mother's feces and if the
mother is shedding the infective cysts in her feces then the young animals
will likely ingest them and coccidia will develop within their intestines.
Since young puppies and kittens, usually those less than six months of age,
have no immunity to coccidia, the organisms reproduce in great numbers and
parasitize the young animal's intestines. Oftentimes this has severe
From exposure to the
coccidia in feces to the onset of the illness is about 13 days. Most puppies
and kittens who are ill from coccidia are, therefore, two weeks of age and
older. Although most infections are the result of spread from the mother,
this is not always the case. Any infected kitten or puppy is contagious to
other puppies and kittens. In breeding facilities, shelters, animal
hospitals, etc., it is wise to isolate those infected from those that are
What are the symptoms
The primary sign of an
animal suffering with coccidiosis is diarrhea. The diarrhea may be mild to
severe depending on the level of infection. Blood and mucous may be present,
especially in advanced cases. Severely affected animals may also vomit, lose
their appetite, become dehydrated, and in some instances, die from the
Most infected kittens
and puppies encountered by the authors are in the four to twelve week age
group. The possibility of coccidiosis should always be considered when a
loose stool or diarrhea is encountered in this age group. A microscopic
fecal exam by a veterinarian will detect the cysts confirming a diagnosis.
What are the risks?
Although many cases
are mild it is not uncommon to see severe, bloody diarrhea result in
dehydration and even death. This is most common in animals who are ill or
infected with other parasites, bacteria or viruses. Coccidiosis is very
contagious, especially among young kittens and puppies. Entire kennels and
catteries may become contaminated with puppies and kittens of many age
groups simultaneously affected.
What is the treatment
It should be mentioned
that stress plays a role in the development of coccidiosis. It is not
uncommon for a seemingly healthy puppy or kitten to arrive at its new home
and develop diarrhea several days later leading to a diagnosis of coccidia.
If the puppy or kitten has been at the new home for less than thirteen days
then it had coccidia before it arrived. Remember the incubation period (from
exposure to illness) is about thirteen days. If the puppy or kitten has been
with its new owner several weeks, then the exposure to coccidia most likely
occurred after the animal arrived at the new home. The authors merely point
this out as they have been involved in legal cases as to who was responsible
for the cost of treatment, the breeder or new owner. Usually coccidia was
present only to surface during the stressful period of the puppy or kitten
adjusting to a new home.
coccidiosis is treatable. Drugs such as sulfadimethoxine
(Tribrissen) and amprolium (Corid) have all been effective in the
treatment and prevention of coccidia. Because these drugs do not kill the
organisms, but rather inhibit their reproduction capabilities, elimination
of coccidia from the intestine is not rapid. By stopping the ability of the
protozoa to reproduce, time is allowed for the puppy's own immunity to
develop and remove the organisms. Drug treatments of five or more days are
How is coccidiosis
prevented or controlled?
Because coccidia is
spread by the feces of carrier animals, it is very important to practice
strict sanitation. All fecal material should be removed. Housing needs to be
such that food and water cannot become contaminated with feces. Clean water
should be provided at all times. Most disinfectants do not work well against
coccidia; incineration of the feces, and steam cleaning, immersion in
boiling water or a 10% ammonia solution are the best methods to kill
coccidia. Coccidia can withstand freezing.
Cockroaches and flies
can mechanically carry coccidia from one place to another. Mice and other
animals can ingest the coccidia and when killed and eaten by a cat, for
instance, can infect the cat. Therefore, insect and rodent control are very
important in preventing coccidiosis.
The coccidia species
of dogs and cats do not infect humans.