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Bufo Toad Poisoning
Cat Home Safety Tips
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Common Things to Watch for
Dental Disease in Pets
Diabetes
Dog Safety Tips
Feline Heartworm Disease
Mallassezia (yeast) Dermatitis
Reasons to Neuter
Noise Phobia in Dogs
Weight Problems in Pets
Otitis (Ear Infections)
Parvo Virus
Pruritis (Itchiness)
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Seizures and Epilepsy
Senior Pets
Reasons to Spay
Toxoplasmosis, Cats and Women
just found out that she is pregnant and was told that she should get rid of her
cat because it could give her a disease called toxoplasmosis, which could harm
her unborn baby. She calls me up to find out if this it true and if she could rush
right over to have her cat tested for this disease.
While part of what the woman was told is true, pregnant women do not
routinely have to give up their furry friend. However, they do need to follow
strict precautions to prevent possible transmission of this disease.
Toxoplasma gondii (Toxo) is an intracellular parasite that causes
toxoplasmosis. Toxo has a very complex life cycle and can infect almost any
warm-blooded animal.
Domestic cats are the "definitive host" for this parasite, meaning that if a cat is
infected with the organism, it will reproduce in the body of the cat and
eventually an infective "oocyst" will be shed in the cat’s feces for a short period
of time. Oocysts can infect other animals and humans.
Important "intermediate hosts" for Toxo include wild rodents, birds, pigs and
sheep. An intermediate host has been infected with the parasite by ingesting
food or water contaminated by oocysts from cat feces. The parasite migrates to
the muscles and forms "tissue cysts" which are a dormant form of organism.
The parasite can then be transmitted to another animal if the intermediate host
is eaten. For example, a cat eating an infected mouse or bird, or a human
eating undercooked pork or lamb.
The danger with Toxo is that it can cause severe birth defects, retardation or
death in an unborn baby under certain circumstances.
About 30-40% of U.S. women of childbearing years have already been exposed
to Toxo at some point in their life and are immune to the disease should they
be re-exposed to it. These women are not at risk of passing the disease on to
their unborn baby.
The 60-70% of women that have never been exposed to the parasite are not
immune to it and are at risk of developing the disease if exposed to oocysts in
their cat’s feces or to tissue cysts in undercooked pork or lamb. If infected
while pregnant, these women could pass the disease onto their unborn baby.
The stage of pregnancy when a woman is infected plays a crucial role in how
severely the fetus is affected. If exposed for the first time during the early part
of the pregnancy the organism is less likely to cross the placenta but if it does it
can cause severe damage to the fetus. If exposed later in her pregnancy, the
organism is more likely to cross the placenta but less likely to harm the fetus.
So what should a woman who owns a cat and is (or plans on becoming)
pregnant do?
First of all, the woman should have her toxo antibody level checked, preferably
before she becomes pregnant. That way she will know if she is already
immune to the disease. Repeating the antibody test in a few weeks may show
a rising antibody level, which may indicate a recent or active infection.
A cat poses a risk to a pregnant woman only when it is shedding oocysts in its
feces. Unfortunately, there is no reliable test for toxo in cats. This is due in part
to the parasite’s life cycle.
Once infected by the parasite for the first time, there is a variable period of time
when the cat is shedding oocysts (and a danger to pregnant women). Fecal
exams are unreliable as oocysts are usually shed before the cat is showing any
signs of illness. Antibody tests are not very helpful either as they are hard to
interpret as to whether the cat has an active infection or prior exposure.
Since it is so difficult to tell if a cat is shedding oocysts, pregnant women
should follow these general guidelines in order to minimize exposure to this
parasite. Keep in mind that a person can be exposed to Toxo even if they do
not own a cat. Therefore all pregnant women should follow the appropriate
guidelines.
Pregnant women should not clean or empty the litter box, this chore should be
delegated to someone else in the family.
The litter box should be emptied once or twice a day. If the cat is shedding
oocysts it takes at least 24 hours for it to become infective to humans. Cleaning
the box daily eliminates the chance of an infective oocyte being present.
Pregnant women should wear gloves and wash their hands thoroughly after
gardening or doing lawn work since outdoor cats may have defecated in the
area and contaminated the soil.
Keep your cat indoors to prevent it from hunting and being exposed to toxo in
a bird or rodent.
Do not feed raw or undercooked meat (especially pork and lamb) to your cat as
it may contain tissue cysts.
Studies have shown that it is highly unlikely for a person to be exposed to toxo
from just petting their cat, but pregnant women should play it safe and wash
their hands after handling their pet.
In addition, pregnant women should not eat undercooked meat because it may
contain tissue cysts. And they should also wash all fruits and vegetables since
they may have been contaminated with oocysts.