What is Toxoplasmosis?
is a parasitic disease caused by an organism called Toxoplasma
gondii. This parasite can infect almost any warm-blooded animal
or bird and humans though cats are the only animals that can
spread this organism through faeces. If a cat does become
infected, it will only shed eggs for around 2-3 weeks in the
cat's life. Cats develop immunity against the parasite, which
usually prevents reinfection and further shedding. Eggs that
have been shed in faeces need to be exposed to air for 1 to 5
days before they become infective to people or other animals
though they can remain infective for up to 18 months in the
animals and humans become infected with this parasite through
ingestion of this parasite, cysts are formed in their tissues
(muscle, brain, etc.), but no adult parasites develop in their
How do people
or animals become infected?
• Ingestion of infective cysts in
tissues by eating or handling raw or undercooked meat (of any
potentially infected animal such as beef, lamb, pork, chicken)
or unpasteurised milk.
• Ingestion of food (eg fruits
and vegetables) or water contaminated with infective eggs (that
have been shed greater than 24 hours prior) from cat faeces (for
example home gardens).
What are the
symptoms and treatment in humans?
people develop minimal or no symptoms. If symptoms occur they
usually resemble the flu; eg fever, enlarged lymph nodes,
fatigue, headache and sore throat. Once exposed to the parasite,
immunity usually develops, preventing re-infection. Most people
require no treatment. People showing symptoms of toxoplasmosis
are generally treated with antibiotics. Treatment for pregnant
women is more complex.
People likely to develop symptoms are children and people with
compromised immune systems. Pregnant women who become infected
with toxoplasmosis risk affecting their unborn baby.
previously non-infected woman becomes infected during pregnancy
with T. gondii, there may be no clinical signs, however there is
a chance that the unborn baby may become infected as well. The
effect on the baby depends heavily on the stage of pregnancy but
is most severe during the first half of the pregnancy. Infection
may result in stillbirths, spontaneous abortions, or the
development of permanent birth defects such as malformations,
mental retardation, impaired vision, and deafness.
becoming pregnant it is a good idea to find out whether you have
been previously infected with Toxoplasma gondii by having an
antibody test. If previously infected, your baby is not at risk
from a new infection. It is important to remember that the only
way to catch Toxoplasma in relation to your cat is from
ingesting faeces exposed to air for greater than a day from a
cat infected for the first time.
and the Immunocompromised
the body, the Toxoplasma parasite never leaves it. Although in
healthy people the parasite remains inactive, it can
"reactivate" in immunocompromised people. There is no additional
danger of transmission of the parasite from their cat. However,
toxoplasmosis in the immunocompromised is a more serious
disease, with the most common manifestation being encephalitis
(inflammation of the brain).
What are the
signs in animals?
are apparent, they usually include vague signs like diarrhoea,
weight loss, decreased appetite, depression and fever.
Measurement of antibodies to T. gondii in the blood is the best
method to diagnose toxoplasmosis. It may be a good idea to check
for some viruses, since usually only immunocompromised cats will
show signs of Toxoplasma. Cats with this disease can be cured
How can I
prevent my pet from becoming infected?
• Keep cats indoors to prevent
them from hunting and eating wild rodents and birds.
• Feed cats only commercially
prepared food or well-cooked meat; never raw meat or raw meat
• Do not let your cat drink
• Faeces should be removed from
the litter box daily and disposed of properly. Clean the litter
boxes regularly with boiling or scalding water.
How can I prevent myself from becoming infected?
• Wash hands, cutting boards,
sink tops, knives and other utensils thoroughly with soap and
water after handling undercooked meat and before eating.
• Cook meat thoroughly to 151
degrees F (66 degrees C) for 20 minutes to destroy any parasites
that might be present. Avoid tasting while cooking.
• Wash vegetables thoroughly
before eating to remove soil that may be contaminated with cat
• Do not drink unpasteurised milk
• Dispose of cat litter every day
before any eggs have time to become infective and sanitise
litter boxes with boiling water. (Many disinfectants are
ineffective against T. gondii.)
• Wear gloves while gardening,
especially where cats may have defecated.
What if I’m
• Pregnant women should minimise
contact with cat faeces, litterboxes, or places cats are known
• It is not necessary to
completely eliminate cats to avoid toxoplasmosis.
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