You might know about the infection toxoplasmosis in relation to
avoiding it during pregnancy by taking precautions with certain
foods and the cat's litter box. According to the Centers for
Disease Control and Preventing (CDC), some 60 million people in the
United States could have toxoplasmosis. Many don't even know it
because it can cause an infection with no symptoms or ones that are
common to other illnesses.
This infection is caused by a microscopic parasite that can live
inside the cells of humans and animals, especially cats and farm
animals.
How It Spreads
People can catch toxoplasmosis from:
- touching or coming into contact with infected cat feces (cats
get the infection from eating infected rodents, birds, or other
small animals)
- eating raw or undercooked meat that's contaminated
- eating uncooked, unwashed fruits or vegetables that have been
contaminated by manure
- being born with it (a woman who gets a toxoplasmosis
infection while pregnant may pass the parasite on to her unborn
child through the bloodstream)
Although infection doesn't normally spread from person to
person except through pregnancy, in rare instances toxoplasmosis
can contaminate blood transfusions and organs donated for
transplantation.
Signs and Symptoms
Toxoplasmosis passes from animals to humans, sometimes without
causing any symptoms. When kids do have symptoms, they vary
depending on the child's age and the immune system's
response to the infection. (As with humans, infected cats often
don't show any signs of a toxoplasmosis infection.)
Toxoplasmosis infections in people fall into three basic
patterns:
- congenital toxoplasmosis, in which a child becomes infected
before birth
- toxoplasmosis in otherwise healthy kids (with the same
symptoms a pregnant woman may have)
- toxoplasmosis in kids with weakened immune systems
Congenital Toxoplasmosis
When a pregnant woman (even one who has no symptoms) catches
toxoplasmosis during pregnancy and remains untreated, there's a
chance that she could pass the infection on to her developing
fetus. Babies who become infected during their mother's first
trimester tend to have the most severe symptoms.
However, it's rare that a woman who got toxoplasmosis
before
getting pregnant will pass the infection on to her unborn baby
because she (and, therefore, her baby) will have built up immunity
to the infection. It can occur, though, if a pregnant woman
who's had a previous infection becomes immunocompromised and
her infection is reactivated. Generally, it's probably a good
idea to wait to try to get pregnant until at least 6 months after a
toxoplasmosis infection.
Up to 90% of children born with congenital toxoplasmosis have no
symptoms early in infancy, but a large percentage will show signs
of infection months to years later. The few who show clear signs of
infection at birth or shortly after may be born prematurely or are
unusually small at birth.
Other signs and symptoms, if there are any, may include:
- fever
- swollen glands (lymph nodes)
-
jaundice
(yellowed skin and eyes caused by abnormal levels of the liver
chemical bilirubin)
- an unusually large or small head
- rash
- bruises or bleeding under the skin
-
anemia
- enlarged liver or spleen
Some babies with congenital toxoplasmosis have
brain and nervous system
abnormalities that cause:
They're also at high risk for eye damage involving the
retina (the light-sensitive lining at the back of the eye
responsible for sight), resulting in severe vision problems.
If a child is born with congenital toxoplasmosis and remains
untreated during infancy, there's almost always some sign of
the infection (often eye damage) by early childhood to
adolescence.
Toxoplasmosis in Otherwise Healthy Kids
A healthy child who becomes infected with toxoplasmosis may have
no symptoms of infection or only a few swollen glands that:
- usually appear in the neck
- are sometimes tender to the touch
- may become larger and smaller over several months
Most kids won't experience any long-term problems if they go
undiagnosed and untreated.
Toxoplasmosis in Kids With Weakened Immune Systems
Kids whose immune systems are weakened (for example, by
AIDS
,
cancer
, or medications taken after organ transplants) are at special risk
for severe toxoplasmosis infections. Especially in children with
AIDS, toxoplasmosis can attack the brain and nervous system,
causing toxoplasmic
encephalitis
(an inflammation of the brain) with symptoms that include:
- fever
- seizures
- headache
- psychosis (a type of severe mental illness)
- problems with vision, speech, movement, or thinking
Duration
Although toxoplasmosis parasites may grow and multiply within a
week of entering a person's body, it may be weeks or months
before symptoms of infection appear (if they appear at all).
Once someone becomes infected with toxoplasmosis, the infection
remains in the body for life, usually in a latent (inactive) form
that won't cause side effects or harm. The infection can be
reactivated, however, if the immune system becomes compromised by
an HIV infection or cancer therapy.
In a child with a healthy immune system, mild symptoms of
toxoplasmosis (such as swollen glands) usually pass within a few
months, even without medical treatment. But kids born with severe
congenital toxoplasmosis may have permanent vision problems or
mental retardation. And in a child with a weakened immune system,
toxoplasmosis can be fatal.
Diagnosis
Doctors can, but rarely do, diagnose toxoplasmosis through
laboratory tests that check for microscopic parasites in the blood,
spinal fluid, amniotic fluid, placenta, lymph nodes, bone marrow,
or other body tissues.
More frequently doctors order blood tests to measure the level
of antibodies (substances that are part of the body's defensive
immune reaction) produced to fight the parasites.
Sophisticated new genetic tests can identify the DNA-containing
genes of toxoplasmosis parasites once they've invaded the body.
These tests are especially useful for checking the amniotic fluid
for evidence of congenital toxoplasmosis in a fetus. Obstetricians
may use ultrasounds to help diagnose congenital toxoplasmosis. But
these tests aren't 100% accurate and can lead to false-positive
results.
Treatment
Unless someone has a weakened immune system or is pregnant,
there's often no need to treat a toxoplasmosis infection -
symptoms (such as swollen glands) usually go away on their own in a
few weeks or months. However, kids should always be checked by a
doctor because swollen glands can be a sign of other illnesses.
If a pregnant woman develops an infection, a treatment plan will
be developed in consultation with her doctor and an infectious
disease specialist. Research has shown that treating the mother can
help decrease the severity of the disease in the infant but
won't necessarily prevent transmission of the infection from
mother to child.
Children born with congenital toxoplasmosis are treated with
different combinations of anti-toxoplasmosis medications, usually
for 1 year after birth. A specialist typically will determine which
medications to use and for how long.
In healthy older kids who develop serious toxoplasmosis
infections, treatment usually lasts 4 to 6 weeks (or at least 2
weeks after symptoms are gone). Kids with weakened immune systems
often need to be hospitalized when they develop toxoplasmosis, and
those with AIDS may need to take anti-toxoplasmosis medication for
life.
When to Call the Doctor
Call your doctor immediately if your child develops symptoms of
toxoplasmosis and:
- is already being treated for AIDS or cancer
- has a condition that affects the immune system
- has been taking medications that weaken the immune
system
Also call the doctor if your otherwise healthy child develops
any of the symptoms of toxoplasmosis.
If you're pregnant, call your doctor immediately if you
notice even one swollen gland, especially if you've been
exposed to cats or have eaten raw or undercooked meat.
Prevention
If your cat is kept indoors and never fed raw or undercooked
meat, then your family's feline probably has a low risk of
catching or spreading toxoplasmosis. Still, you can also catch it
from eating raw meats or uncooked produce that's
contaminated.
To help prevent toxoplasmosis in your family:
Food Tips
-
Cook meats thoroughly
.
-
Wash your hands
with soap and water after handling raw meat or unwashed
vegetables.
- Wash all fruits and vegetables before serving. You may also
want to peel them.
- Freeze meat for a few days before cooking it, which helps to
reduce the likelihood of toxoplasmosis infection, says the
CDC.
- Thoroughly wash all cutting boards, utensils, and kitchen
surfaces (especially those that come into contact with raw meat)
with hot soapy water after each use.
- Cook all meats completely (the juices should be clear and
there should be no pink areas).
Cat Tips
- If you're pregnant, have someone else change your
cat's litter box. And ask that he or she use detergent and
hot water to clean it, then wash his or her hands after changing
the litter. If you are unable to have someone else change the
litter box, wear gloves when you do it and wash hands thoroughly
afterward.
- Keep your cat inside at all times to keep your pet from
getting toxoplasmosis from the soil and/or small infected animals
it tries to catch or eat.
- Keep your child's outdoor sandbox covered, especially
overnight, to prevent wandering cats from using it as a litter
box.
- Don't feed your cat raw meat.
- Steer clear of stray cats.
- Don't take in a new cat if you're pregnant.
General and Household Tips
- Wear gloves when gardening and wash your hands
afterward.
- Use window screens to try to keep your home bug-free (cat
feces are a favorite haunt of flies and cockroaches and the bugs
can spread the feces, and the toxoplasmosis, onto food).
- Don't drink untreated water, especially if you're
traveling in underdeveloped countries.
Reviewed by:
Joel Klein, MD
Date reviewed: November 2008
Note: All information is for educational purposes only. For specific medical advice,
diagnoses, and treatment, consult your doctor.
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