In the many years I've worked in rescue, I have encountered people giving up their cats, or being told by their doctors to do so, due to toxoplasmosis risk. It's unfortunate since not only is this unnecessary according to the CDC (Center for Disease Control), it's not even the most common way to contract the disease.
Oddly, while it seems everyone thinks of cats when they think of toxoplasmosis, the far more likely culprit is handling raw or undercooked meat, since meats are very likely fecally contaminated. The CDC classifies toxoplasmosis as a food borne illness, not a zoonosis (a disease that can be transmitted directly from non-human-animal to human). Fully cooked to the recommended temperature, the fecal bacteria in meat is rendered inactive, but pregnant women and the immunocompromised should never handle raw or undercooked meat. I get annoyed that doctors tell people to dump their beloved pets (even strictly indoor cats who are very unlikely to be carriers), yet don't tell them to have someone else cook any meat for them (or not to eat meat at all), since that's actually a far a bigger concern.
Gardening is another way that humans can contract Toxoplasmosis. Wildlife feces is prominent in soil, and the CDC cites this as another risk factor, yet I haven't heard of a rush of pregnant women being told to fear their gardens the way doctors tell them to freak out about their cats.
Toxoplasmosis is a relatively minor infection provided you aren't pregnant or immune compromised, but if you are, it can cause serious illness. You have to actually ingest infected feces to get it, and so does your cat, so you can help prevent exposure by keeping cats indoors so they don't eat wildlife and their feces-filled innards. Another way to avoid it? Clean the litterbox daily since the Toxoplasmosis parasite does not become active and transmissible for 24 hrs to 5 days after being shed. It doesn't hurt to wear gloves and a mask, and use basic sanitation skills when scooping the litterbox, and ideally, if you are in the high-risk group and want to be super duper absolutely careful (and why not?) you can have someone else scoop the box.
I think doctors get overexcited sometimes about things pets can transmit, despite those diseases being extremely few compared to what humans transmit to each other. They also seem more worried about what you can get from the living animals on our sofas, than the dead ones in the kitchen. You're *far* more likely to become extremely ill from exposure to food borne illness, your toddler or small child, his friends, and your co-workers, than get sick from anything our pets are likely to carry, particularly when our pets are kept healthy, vetted, vaccinated, clean and indoors.
It seems people are much more likely to believe that their pets are dangerous to their health than any of the things that *really* risky in our surroundings. I suppose it's because people still, sadly, see pets as disposable, making it easy believe we can get rid of the risk by getting rid of the pet. I'd love to see the concept of disposable, "give-away" pets come to an end. It would make rescue so much easier and allow shelters to cut their "euthanasia" rates dramatically.
In the mean time, when you hear someone spreading the idea that cats are dirty animals that need to be tossed aside out of fear of Toxoplasmosis, please set them straight. Send them to the CDC website, and make sure they know they shouldn't fear their feline.