Toxoplasma gondii
Keeping your cat indoors will also stop the spread of the parasite Toxoplasma gondii by limiting where your cat can defecate. According to the Centers for Disease Control:
“Although T. gondii can infect most warm-blooded animals, cats are the only host that shed an environmentally resistant form of the organism (oocyst) in their feces. Once a person or another warm-blooded animal ingests the parasite, it becomes infectious and travels through the wall of the intestine. Then the parasite is carried by blood to other tissues including the muscles and central nervous system.”
In other words, your neighbor’s cat pooping in the flower bed or children’s play area could be depositing T. gondii and increasing the likelihood of human contact and infection. T. Gondii is considered a global threat to human health. Infection can cause eye disease leading to vision loss. Pregnant women can transmit it to the fetus. The CDC lists the eating of raw or undercooked meat containing Toxoplasmosis as “the leading cause of foodborne illness-related death and hospitalization in the US.”
Of course, the CDC’s concern is human health (CDC, “Toxoplasmosis”). Who knows the cost to other mammals? Previously it was thought that T. gondii would only be found in terrestrial animals. Now it’s being found in marine and freshwater species indicating T. gondii is contaminating their waters and food sources. T. gondii is a major source of mortality in sea otters (The Marine Mammal Center, “Toxoplasmosis Poses Threat for Sea Otters Like Yankee Doodle”).