from Modesto, Cal., is the caretaker for Sassy, a
4-year-old tabby cat that Ellen loves dearly. Ellen is
also pregnant and has concerns about being pregnant
while living with a cat. Sassy is entirely indoors and
Ellen has heard — without much detail — about
problems that can occur to babies because of the mother’s
exposure to cats during their pregnancy. She would like
to understand any potential problems and risks.
is a disease process called feline toxoplasmosis that
has been implicated in people. I will outline this
process in some detail to help clarify it and the risks,
if any, involved.
toxoplasmosis is caused by a protozoal agent called
Toxoplasma gondii. This organism lives in members of the
cat family, including domestic cats, where it reproduces
in the small intestine and sheds its offspring, called
oocysts, in the feces.
is also a part of the life cycle where the organism
disseminates throughout the body becoming encysted
within various body tissues. This encysted form can
occur in other types of animals including fish,
amphibians, reptiles, birds and other mammals —
including humans. These other hosts are called
intermediate hosts because the organism does not have
its reproduction in them. The reproductive host is the
cat, considered the definitive host.
become infected by contact and ingestion of the oocysts
shed from the feces of an infected cat or by eating an
intermediate host with the cysts within its tissue.
About 50 percent of the cats that are exposed will
actually shed out the oocytes in their feces.
cats can have symptoms including coughing, and
difficulty breathing, changes in the eyes including
redness and evidence of eye pain, seizures, muscle and
joint pain — and the list goes on. These symptoms
relate to where the cysts show up in the cat’s body.
The disease is treatable and these cats generally do
exposure to this disease from cats is very unlikely.
First of all, cats that are infected with this organism
will shed the oocysts in their feces only during one
time period, a few days to a few weeks, once in their
life. These oocysts must undergo a process called
sporulation before they can become infectious to people
and this process does not occur in fresh feces.
are very fastidious and do not allow feces to remain on
their skin long enough for the oocysts to become
infective. Due to the short shedding period and the very
low chance of exposure to infective oocysts, it is
likely not necessary to remove companion cats from the
household of pregnant women.
has also been concern expressed with cats shedding this
disease in households with immune compromised people.
For the reasons listed above, this too is unlikely to be
reason that pregnant women are considered at risk for
toxoplamosis is because of the encysted form of the
organism invading the developing baby. This can cause
damage to tissues and problems for the baby as a result.
This subject is not in my realm of expertise and is best
left to discussion with your physician.
to Toxoplasma in people is more likely to occur from
working with contaminated soil or drinking contaminated
water. These oocysts can live in the environment for
long periods of time.
avoid any exposure to this organism, high-risk people
should avoid feeding their cats anything but cat food.
Do not allow cats to hunt. Clean the litterbox daily —
remember that fresh feces are not infective. It is best
for pregnant women to avoid cleaning the litter box.
That is what their partners are for!
a litterbox liner can be helpful. Wear gloves when
working in the soil. Keep children’s sandboxes covered
to avoid their use by stray cats for defecation. Do not
drink water from potentially tainted sources.
these simple recommendations should eliminate any chance
of contact with this organism and thus avoid any disease
it might cause.