Coccidia are small
protozoans
(one-celled organisms) that multiply in the intestinal
tracts of dogs and cats, most commonly in puppies and
kittens 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 present).
In
dogs and cats, most coccidia are of the genus called
Isospora. Isospora canis and I.
ohioensis are the species most often encountered in
dogs. Regardless of which species is present, we generally
refer to the disease as coccidiosis. As a puppy ages, he
tends to develop a natural
immunity
to the effects of coccidia. As an adult, he may carry
coccidia in his intestines, and shed the
cyst
in the feces, but experience no ill effects.
How are coccidia transmitted?
A puppy
is not born with the coccidia organisms in his intestine.
However, once born, the puppy is frequently exposed to his
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,
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 effects.
From
exposure to the coccidia in feces to the onset of the
illness is about 13 days. Most puppies 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 puppy or
kitten is contagious to other puppies or kittens. In
breeding facilities, shelters, animal hospitals, etc., it
is wise to isolate those infected from those that are not.
What are the symptoms of coccidiosis?
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 disease.
Most
infected 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
puppies. Entire kennels may become contaminated, with
puppies of many age groups simultaneously affected.
What is the treatment of coccidiosis?
It should
be mentioned that stress plays a role in the development
of coccidiosis. It is not uncommon for a seemingly healthy
puppy to arrive at his new home and develop diarrhea
several days later leading to a diagnosis of coccidia. If
the puppy has been at the new home for less than thirteen
days, then he had coccidia before he arrived. Remember,
the incubation period (from exposure to illness) is about
thirteen days. If the puppy has been with his new owner
several weeks, then the exposure to coccidia most likely
occurred after the animal arrived at the new home.
Fortunately, coccidiosis is treatable. Drugs such as
sulfadimethoxine (Albon®)
and trimethoprim-sulfadiazine (Tribrissen®)
have 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.
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 dog, for
instance, can infect the dog. Therefore, insect and rodent
control is very important in preventing coccidiosis.
The
coccidia species of dogs and cats do not infect humans.
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