You may have heard that Toxoplasmosis is a disease that is dangerous for pregnant women and immunocompromised individuals. Beyond this basic information, many myths abound. Does it mean you need to give up your feline friend? Do you need to get tested? Is it safe to clean the litter box? A little knowledge can go along way towards addressing your concerns and fears.
What It Is
Toxoplasma gondii is a tiny protozoan that can infect any mammal. Cats are considered the main host, since they are the only animal in which the organism can complete its entire life cycle.
How People Get It
Although cats are frequently blamed as the primary source of infection, this is a misconception. More commonly, people are exposed when they eat undercooked meat. Scientific studies show that the organism can be found in up to 20% of meat samples tested.
Cats can be a source of infection, but it is less common. Cats get the organism by hunting outdoors and eating other infected animals. When a cat first becomes infected, it goes through a brief period in which it can pass the organism in its feces. This only lasts for a few weeks. When the organism is passed in the cats feces, it is not immediately infectious to humans; it must sit for several days first. If the litter box is cleaned out daily, it is quite unlikely for cat owners to directly contract the organism from their own cats.
Its more likely for a person to be infected if they garden in soil in which cats have defecated. The organism can survive in the soil for years. The organism still must be swallowed. This could happen if a person put his hands in his mouth without washing or ate unwashed vegetables that were grown in the contaminated soil.
The final method of infection is congenital, when a pregnant woman with an active case of Toxoplasmosis passes the organism to her fetus while it is in the uterus. Women are only likely to be infectious to their fetuses when they initially become infected.
Toxoplasmosis in People
In the United States, only 1-2% of people show evidence of exposure to Toxoplasma. The organism does not cause any symptoms at all in most people. Immunosuppressed individuals are much more likely to become infected by Toxoplasma and may suffer serious consequences such as encephalitis. Infection of a fetus with Toxoplasma can result in miscarriage, congenital brain disorders, or congenital eye disorders.
Symptoms in Cats
Symptoms in cats are rare, but are more likely to occur in young cats with weak immune systems and in cats that are immunosuppressed as a result of infection with Feline Leukemia Virus (FeLV) or Feline Immunodeciency Virus (FIV). Symptoms can include weight loss, pneumonia, and eye disorders.
Whether it is necessary to be tested for Toxoplasmosis is a decision that you should make with your physician. There are blood tests available that can detect if you have a current, active infection or if you have been exposed in the past, but do not have a current infection.
To minimize the chance of exposure to Toxoplasma, always cook meat thoroughly. Wash your hands, cutting boards, and utensils after working with raw meat. Wear gloves when gardening outdoors. Clean litter pans every day. The need for pregnant women and immunocompromised people to avoid cleaning litter boxes is controversial. Women who test positive for exposure prior to pregnancy are unlikely to pass the disease to their fetus, so it is probably safe for them to clean the litter box. Women who have not been previously exposed and immunocompromised individuals should probably avoid cleaning litter boxes if possible, especially if their cats hunt.