Every year, 1.2 metric tons of cat feces are deposited in the US, raising the risk of infection with the Toxoplasma gondii parasite, researchers from the Stanley Medical Research Institute and Johns Hopkins University Medical Center reported in Trends in Parasitology (July 10th, 2013 issue).
Some cat feces are contaminated with Toxoplasma gondii, a protozoan known to cause toxoplasmosis epidemics in healthy individuals, not just patients with weakened immune systems and pregnant mothers.
Co-author, E. Fuller Torrey, said: "The accumulation of Toxoplasma gondii oocysts, found in cat feces, may be a much bigger problem than we realize because of their apparent long life and their association with some diseases."
Torrey said authorities need to gain better control of cat populations, especially feral cats. He also called for more research.
American backyards and communities contain between 3 and 400 oocysts per square feet. Just one single Toxoplasma gondii oocyst can infect a human.
Cats become infected when they catch infected mice, birds and other small mammals. The infected cat then spreads oocysts through its feces in soil, water, grass, etc.
If you have a pet cat, no mice or rats in your home and your pet stays indoors all the time, you have nothing to worry about, Torrey said. If it does spend time outdoors, be extremely careful with litter boxes, makes sure sandboxes are covered, and wear gloves when you are gardening.
Torrey quoted one study showing that 100 T. gondii oocysts may be found under your fingernails.
Co-author Robert Yolken says parents, teachers and guardians need to be extra careful with young children.
Should we get tested? - Torrey says: "No, except perhaps in the case of pregnant women. Fifteen percent of us have antibodies, including me." Somebody may test positive one day and negative the next.
Toxoplasmosis prevention in newborns inadequate in USA - American babies born with toxoplasmosis have significantly higher rates of eye and brain damage compared to infants in Europe, researchers from Stanford University School of Medicine reported in Pediatric Infectious Disease Journal.
What is Toxoplasmosis?
Toxoplasmosis is a disease caused by the common Toxoplasma gondii parasite.
Signs and symptoms of toxoplasmosis are usually "flu-like" and may include
The majority of infected people will have no signs or symptoms at all.
For people with weakened immune systems, such as patients with cancer, AIDS, or transplant organ recipients on immunosuppressive medications, signs and symptoms may include the same as those listed above, plus:
- Coordination problems
- Seizures (fits)
- Tuberculosis-like complications
- Ocular toxoplasmosis - severe inflammation of the retina
Toxoplasmosis during pregnancy
If a pregnant woman becomes infected with Toxoplasma gondii, there is a 30% chance that the developing fetus will also become infected (congenital toxoplasmosis), even if the mother has no symptoms.
The pregnant mother is more likely to pass on the infection during the third trimester. However, the risk of more serious outcomes is greater earlier on during the pregnancy.
The following risks and complications are possible if the pregnant mother becomes infected with Toxoplasma gondii:
- Miscarriage or stillbirth
- The baby may suffer from seizures
- The newborn will have jaundice
- The infant may have serious eye infections
- The newborn may have brain damage
- The baby's liver and spleen may be enlarged
- Most complications appear when the child is a teenager or later, and may include:
- recurrent and serious eye infections
- rheumatoid arthritis
- brain cancer
- mental problems, including schizophrenia, obsessive-compulsive disorder, and problems in school
Cat population explosion worldwide
As background information, Torry and Yolken informed that between 1989 and 2006 in the US, cat ownership rose by about 50%, from 54.6 million to 81.7 million. However, during the same period, the country's human population grew by only 23%. There are also between 25 and 60 million feral cats in the US.
In the UK, cat ownership rose from 4.5 million in 1990 to 8 million in 2009. Cat ownership has increased all over the world, especially in China and Latin America.
Some cat owners are very close to their pets. Torrey quoted one study showing that 62% of cats sleep with their adult owners and another 13% slept with children.
Written by Christian Norqvist