No, not all outdoor cats have toxoplasmosis, but they have a significantly higher risk of infection because they hunt and eat infected prey (like rodents, birds) or scavenge raw meat, making outdoor cats a major source of the parasite Toxoplasma gondii in the environment, though most infected cats shed the parasite only briefly and rarely show symptoms. Prevalence varies greatly by location, with some studies showing high rates in feral populations but low rates of active shedding at any given time.
Animal-to-human transmission
Most outdoor cats are infected by T. gondii because they hunt and eat small animals that are intermediate hosts. Millions of parasitic eggs, also known as oocysts, enter the environment through cat feces.
The prevalence of oocyst shedding in cats is very low (0-1%), even though at least 15-40% of cats have been infected with Toxoplasma at some point. This means very few cats at any one time are actually able to pass their infection on to people.
Protecting your cat from toxoplasmosis may also help to protect you from toxoplasmosis. Feed your cat commercial dry or canned food. Never feed cats raw meat because this can be a source of Toxoplasma infection. Keep indoor cats indoors so they do not become infected by eating small animals.
What is the likelihood that my baby will have toxoplasmosis? Fortunately, the risk of maternal transmission of the parasite to the fetus during the first trimester of pregnancy (when the baby is most vulnerable) is relatively low — at 15-20 percent.
Prevalence of Toxoplasma and Toxocara Among Stray and Household Cats and Their Owners. Monitoring of the T. gondii B1 gene showed that 15.2% (20/132; 95% CI 10.0–22.2) of stray cats, 18.2% (6/33; 95% CI 8.6–34.4) of household cats, and 51.5% (17/33; 95% CI 35.2–67.5) of cat owners were infected with T. gondii.
Decontamination: Toxoplasma is inactivated by either 70% ethanol or Vesphene. All contaminated materials must be disinfected (alcohol, bleach) or autoclaved after use.
It is unlikely that you would be exposed to the parasite by touching an infected cat, because they usually do not carry the parasite on their fur. It is also unlikely that you would become infected through cat bites or scratches.
Once infected, the animal can shed the parasite in the feces (poop) for up to two weeks. Toxoplasma gondii eggs can live in cat feces or buried in soil for up to 18 months.
Toxoplasma can be picked up anywhere an infected cat has defecated, such as the litter box, sandbox, garden or yard. Other routes of infection include consumption of contaminated water, undercooked meat or shellfish. Most people experience mild illness and can get the infection under control.
Cats shedding oocysts can pose a risk to humans. However, they shed only once in their lifetime, and usually for only 3–10 days after ingestion of tissue cysts. Cats with T gondii antibodies no longer shed oocysts; they neither are nor will become a zoonotic risk.
Rabies is a zoonotic disease, meaning if your cat is infected, it can spread the deadly disease to you and other humans. Feline immunodeficiency virus (FIV) and Feline infectious peritonitis (FIP) are two additional infectious diseases that outdoor cats are more likely to be exposed to.
To become infected yourself, you must somehow ingest an infected cat's feces while it is actively shedding parasite eggs. This is possible if you don't wash your hands after cleaning a litter box, or accidentally ingest anything that met with infected cat feces. Toxoplasmosis is not transmitted through the skin.
In most cases of animal and human infection, toxoplasmosis does not cause any symptoms. The only evidence of infection is detection of antibodies in the blood against the toxoplasmosis parasite. Symptoms, if they do occur, include: Swollen lymph glands, especially around the neck.
Key points. Most people with healthy immune systems recover from toxoplasmosis without treatment. Talk to your healthcare provider about treatment options if you are pregnant or immunocompromised (have a weakened immune system).
How is toxoplasmosis spread? Accidental ingestion of undercooked, contaminated meat or shellfish after handling them and not washing hands thoroughly (Toxoplasma cannot be absorbed through intact skin.)
The parasite Toxoplasma gondii is carried by 30 per cent of the Australian population, and is a significant cause of miscarriage and birth defects. Our researchers have discovered that a factor called protein kinase A (PKA) is required for Toxoplasma gondii to invade a host cell.
How to prevent the transmission of toxoplasmosis
The Toxoplasma gondii protozoan parasite causes toxoplasmosis. Approximately 11 percent of the US population 6 years and older have had a Toxoplasma infection. In various places throughout the world, research shows that more than 60 percent of some populations have had Toxoplasma infection.
Some cases of acute toxoplasmosis in adults are associated with psychiatric symptoms such as delusions and hallucinations. A review of 114 cases of acquired toxoplasmosis noted that “psychiatric disturbances were very frequent” in 24 of the case-patients (10).
There is currently no licensed vaccine available for humans.