Infection by just a few roundworms usually causes no problems, but more severe infections may cause fevers, bronchitis, asthma, or vision problems. Another concern with cat feces is toxoplasmosis, a parasite that infects humans and other animals. Toxoplasmosis is a serious concern for pregnant women, persons with AIDS, and patients receiving immunosuppressive treatments. Most others who contract toxoplasmosis exhibit mild symptoms, such as headaches, muscle aches, swollen lymph nodes, or sore throats. Humans become infected with toxoplasmosis primarily by injesting contaminated food and water.
Gardens are a secondary source of infection.
Roundworms and toxoplasmosis need not deter you from gardening. Keep pets from using your vegetable garden as a toilet. Laying 1-inch mesh chicken fencing over the vegetable bed usually deters pets but allows vegetables to grow up through it. Regularly clean up and dispose of dog and cat droppings. Treat your dogs and cats for roundworms.