This information is provided by
Provet for educational purposes only.
You should seek the advice of your
veterinarian if your pet is ill as only he or she can correctly advise on the
diagnosis and recommend the treatment that is most appropriate for your pet.
Toxoplasmosis is a serious zoonosis
which veterinarians should be educating their clients about....particularly
clients who are at risk. Good management and basic hygiene are all
prerequisites to minimising the risk of transmission from cats to humans.
Toxoplasmosis infection in many species - including humans and cats - does
not cause any clinical signs in most patients. However, an unborn fetus, very
young children and immune-deficient individuals are at high risk from this
single-celled parasite and can develop serious disease. In some parts of the
USA 30% of the childbearing-age women in the population have been exposed to
Toxoplasma spp and it is present in 10% of HIV positive patients.
Most infected humans show no signs of the disease, but when they occur they
- Sore throat
- Nasal congestion
- Loss of appetite
- A skin rash
- Swollen lymph nodes (lymphadenopathy)
- Joint pain
Humans get infected from :
- Eating undercooked infected meat - usually goat, mutton or pork.
- From contact with oocysts shed in cat faeces - direct or indirect
through contact with soil, or cat litter.
- In-utero from an infected mother (congenital infection)
- From infected organ transplantation (rare)
Human workers most at risk include :
- Animal handlers
In cats the organisms lifecycle is as follows :
- Cat ingests the infectious agent (T. gondii) in food - eg by
eating an infected rodent
- The cat starts passing oocysts in it's faeces 3-4 days after eating the
- Oocysts continue to be shed in the faeces for only 10-14 days after
initial infection ** So cats which test positive to
Toxoplasmosis do not necessarily represent a serious risk to the human
- The cat shows no signs of illness
- The oocysts take 1-5 days to mature in the soil or litter.**
So contact with fresh faeces carries a low risk of transmission compared
with contact with "old" faeces.
- Oocysts are then infectious to animals and humans
- If ingested - these infective oocysts cross the intestinal wall, enter
the bloodstream and encyst in various end-tissues including the
- The parasite remains viable inside the cysts indefinitely in living
animals, and for several days after the individual dies.
Recommendations to minimise the risk of transmission of T gondii from
cats to humans :
- Basic hygiene - wear disposable gloves when handling cat faeces,
contaminated soil, litter trays.
- Clean out litter trays daily - so removing faeces before the infective
stage oocysts have developed
- Wash hands rigorously after handling cat litter trays or contaminated
- Prevent children playing in areas known to be contaminated with cat
faeces - soil borders in gardens, sand pits, and so on.
- Prevent direct contact between potentially infected cats (especially
rodent eaters) and pregnant women, young children and people with a
compromised immune system.
Updated October 2013