The single most effective way to prevent toxoplasmosis in cats is to keep them indoors and away from prey animals. Up to 97% of cat infections happen when a cat eats a rodent, bird, or other small animal carrying the parasite. Everything else, from diet to litter box hygiene, builds on that foundation.
Toxoplasmosis is remarkably common in cats. A study of nearly 200 domestic cats in Poland found that about 50% tested positive for antibodies against the parasite, meaning they had been exposed at some point. Older cats showed significantly higher rates, reflecting a lifetime of potential exposure. The good news: most infected cats never show symptoms, and with a few straightforward changes, you can dramatically reduce the chance your cat picks up the parasite in the first place.
Why Hunting Is the Biggest Risk Factor
Cats are the only animal in which Toxoplasma gondii completes its full life cycle. When a cat eats an infected mouse or bird, the parasite’s tissue cysts break open in the stomach and intestine, and within 3 to 10 days the cat begins shedding microscopic eggs (called oocysts) in its feces. This shedding period typically lasts up to 21 days and peaks within the first month of infection.
Rodents are by far the most common source. Cockroaches and earthworms can also carry the parasite and act as accidental delivery vehicles if your cat eats them. Any cat with outdoor access and hunting instincts faces ongoing exposure every time it catches prey.
Keep Your Cat Indoors
An indoor-only lifestyle eliminates the main transmission route. Cats that never hunt infected animals have a near-zero chance of picking up tissue cysts, which account for the overwhelming majority of new infections. If your cat already goes outdoors, transitioning to indoor life can feel like a big change, but environmental enrichment (climbing shelves, puzzle feeders, interactive toys, window perches) helps replace the stimulation of outdoor roaming.
If keeping your cat fully indoors isn’t realistic, supervised outdoor time in an enclosed patio (a “catio”) or on a harness gives your cat fresh air without the chance to hunt. The goal is simple: no contact with rodents, birds, or other small prey.
Feed Commercial or Well-Cooked Food Only
Raw feeding trends have made this a common concern. The CDC recommends feeding cats only canned or dried commercial food, or well-cooked table food. Never offer raw or undercooked meat, which can contain tissue cysts that survive at room temperature.
If you prepare homemade cat food and want an extra safety margin, freezing meat at 0°F (-18°C) or below for several days before cooking greatly reduces the chance of viable parasites surviving. Cooking thoroughly after freezing provides the strongest protection. Raw-diet advocates sometimes dismiss the risk, but the parasite’s tissue cysts are specifically designed to survive in muscle tissue until consumed by a new host.
Litter Box Hygiene and the 24-Hour Window
Even if your cat does become infected, smart litter box habits protect both you and your household. Freshly shed oocysts are not immediately dangerous. They need 1 to 5 days in the environment to sporulate (mature into an infectious form), with most becoming infectious between 48 and 72 hours after being passed in feces.
This creates a practical window: scooping the litter box daily, ideally every 24 hours, removes oocysts before they can become infectious. Use a scoop, wash your hands thoroughly with soap and water afterward, and dispose of waste in a sealed bag. Pregnant women and immunocompromised individuals should have someone else handle litter duty entirely.
One important detail about cleaning: standard household bleach does not kill Toxoplasma oocysts. Studies have shown that sodium hypochlorite (the active ingredient in bleach) fails to inactivate oocysts even at high concentrations over 24 hours. Ozone is similarly ineffective. What does work is heat. Pouring boiling water over the empty litter box after dumping the litter will kill oocysts on contact, since temperatures above 122°F (50°C) held for 30 minutes destroy their infectivity, and boiling water works almost instantly. For chemical disinfection, ammonia solutions at 5% concentration for 30 minutes or tincture of iodine at 2% for 10 minutes are effective, though these are less practical for routine home use than simply using hot water.
Control Rodents Around Your Home
Even indoor cats can encounter mice that find their way inside. Keeping your home free of rodents removes the most likely source of infection. Seal gaps around pipes, doors, and foundations. Store pet food and human food in sealed containers. If you use traps, place them where your cat cannot reach them or encounter a caught mouse before you dispose of it.
Outdoors, reducing rodent habitat near your home helps too. Clear brush piles, secure garbage bins, and avoid leaving food sources that attract wildlife. If neighborhood cats use your garden as a litter box, cover vegetable beds and sandboxes, and wear gloves when gardening in soil where cats may have defecated.
Protect Outdoor Water and Food Sources
Cats can, in rare cases, pick up the parasite from contaminated water or soil rather than from prey. Only about 20% of cats fed oocysts directly will go on to shed, so this route is far less efficient than eating infected tissue. Still, it’s worth addressing. Keep your cat’s water bowl clean and filled with fresh water rather than letting them drink from puddles, garden ponds, or standing water outdoors, which could be contaminated with oocysts from other cats’ feces.
What Testing Can and Cannot Tell You
If you’re curious whether your cat has been exposed, your vet can run a blood test looking for antibodies against the parasite. A positive IgG result means your cat encountered the parasite at some point but doesn’t tell you whether the infection is recent or long past. IgM antibodies suggest a more recent infection, but results can be inconclusive. No blood test can confirm whether your cat is actively shedding oocysts right now.
For cats with possible exposure and unclear blood results, a PCR test on fecal samples can detect parasite DNA directly. In practice, though, testing is most useful as a screening tool for cats in households with pregnant women or immunocompromised individuals, helping gauge the overall risk level rather than providing a definitive all-clear.
No Vaccine Exists Yet
There is currently no commercial vaccine to prevent toxoplasmosis in cats. Research is active, with experimental vaccines showing promise in reducing parasite levels in lab settings, but none have reached the market. Prevention remains entirely about managing your cat’s environment and diet.
After Infection: What to Expect
Most cats that become infected show no symptoms at all. When signs do appear, they can include mild lethargy, decreased appetite, or fever, and typically resolve on their own in healthy adult cats. The shedding period is relatively brief, usually under three weeks, and most cats only shed oocysts once in their lifetime unless their immune system becomes significantly compromised later.
This means that a cat who was infected years ago and has since recovered poses very little ongoing risk. The greatest danger comes from a cat’s first infection, when oocyst production peaks. Keeping a young, newly adopted, or outdoor-transitioning cat indoors and on commercial food during those early months is one of the highest-impact steps you can take.