Toxoplasmosis is one of the best known of the zoonotic diseases that involve pets
and is the disease that leads many pregnant women to (unfairly) toss the pet cat
out the door!
Although cats play a major role in the life cycle of Toxopllasma gondii, the causative organism,
humans can in fact become infected 3 different ways, only one of which is direct contact
with cat faeces.In fact, cat ownership is not a big factor for human infection with Toxoplasma.
Ways that humans can become infected
1) Eating undercooked meat
This is THE major route of infection for humans, NOT contact with cat faeces.
In one study , up to 60% of infections were as the result of the consumption of undercooked
Another study showed that up to 25% of lamb and pork meat sampled in the USA contained
the toxoplasma organism, while poultry was found to have a much lower risk because it is
often frozen during processing.
2) Transplacental Infection
This is the major fear of pregnant women because of the potential effects of toxoplasmosis
on the unborn child. These include spontaneous abortion, blindness, epilepsy,
mental retardation, hydrocephalus etc etc.
The foetus is infected usually only when the mother experiences an acute infection during, or
very shortly before, pregnancy.The greatest risk of transmission of the infection to the unborn
baby occurs when the mother becomes infected in the third trimester. However, the greatest damage to the
foetus occurs with infections during the first trimester.
Many babies infected in the uterus are asymptomatic at birth but many of them (80%+) wii
develop symptoms later in life if not treated.
3) Ingestion of the organism shed in cat faeces.
Cats only shed Toxoplasma oocysts in their faeces for about 14 days after they first
become infected. These oocysts then require a period of at least 1 to 5 days before
they become infectious.
Thus contact with fresh cat faeces is less risky than contact with cat faeces left in
a litter box for a few days or cat faeces in normal garden soil.
Interestingly, it has been estimated that less than 1% of cats shed Toxoplasma.
Ways to Prevent Human Infection
1) Cook meat properly
2) Wear gloves when gardening
3) Wash hands and utensils after working with raw meat
4) Wash fresh vegetables
5) Clean litter trays out daily
6) Don't feed cats raw meat
7) Avoid gardening and litter trays when pregnant.
is a potentially very nasty zoonotic disease, please keep in mind that getting rid of the pet cat(s) is not a solution to the potential problem.
In fact, it could give you a false sense of security!