The next in my series of articles about toxoplasmosis concerns the risk factors and transmission of the disease. Some estimates have around 22.5% of all individuals over 12 years of age infected with toxoplasmosis in the United States. The disease is especially common in areas with hot, humid climates and at lower altitudes. In fact, some countries have an incidence of toxoplasmosis around 95%. Clearly, this is a very common parasite and a very common disease.
There are two main methods of transmission of toxoplasmosis. The disease cannot be passed from person-to-person except congenitally where a pregnant mother passes the disease to her infant. In addition, blood transfusion and organ transplantation are methods by which the disease is transmitted, but are obviously quite rare. Instead, most cases of toxoplasmosis are contracted through food-borne transmission, animal-to-human transmission, and as already mentioned, congenital transmission.
Food-borne transmission occurs when the tissues from the parasite has infected some food source. Eating undercooked meat, accidentally or otherwise; especially lamb, pork, and venison can lead to the transmission of toxoplasmosis. Similarly, you may accidentally ingest the parasite if you do not properly wash your hands after handling raw meats. Finally, knives, forks, cutting boards, or other raw foods that come in contact with contaminated foods likewise become contaminated and may increase your risk of contracting the disease.
The most common form of animal-to-human transmission involves cats. Because cats, especially outdoor cats, often eat infected rats, birds, and other small animals, cats often carry the toxoplasmosis parasite. The parasite can then be shed in feces for as long as 3 weeks after infection. Therefore, your cats litter box can become contaminated with toxoplasmosis and it is easier for other times around the house to also become contaminated. You may accidentally ingest the parasite while cleaning a litter box or by touching things that have contacted your cats feces. As such, it is always especially important to take care when cleaning your cat’s litter box.