If you're a crazy cat person (or just one of those weird, "Aww, you're cute, now leave me alone," people), you have likely contracted a parasite and you didn't even notice it. In fact, an estimated 40 to 60 million people in the US alone and more than two billion people world-wide are believed to be infected. The parasite, Toxoplasma gondii, is usually transmitted through raw meat containing T. gondii cysts, or water containing oocysts from feline feces — cat poo. The disease it causes, toxoplasmosis, can be very dangerous. Let's look at what this dastardly parasite is and how it affects both humans and our feline friends.
What is Toxoplasmosis and What are the Signs:
The lifecycle of T. gondii, or Toxoplasma, occurs in two types of hosts — a primary host and an intermediate host. The main host are members of the family Felidae, which includes domestic cats and their relatives.
In the primary host, the parasite reproduces sexually and hatches tiny little eggs known as oocysts, which are shed in the cat's feces. These contaminate plants and water and are then ingested by animals in the wild, such as birds and rodents. These are the intermediate hosts.
In the intermediate host, the parasite reproduces asexually to essentially make millions of little clones of itself, which group together and produce cysts in the tissues of the intermediate host. When a cat eats infected prey, the parasite is released into its digestive tract from the cysts, where it then reproduces quickly and with a vengeance.
Once the cat is thoroughly infected, it begins to shed millions of the oocysts in through its feces. Typically, cats that have never been infected before start shedding oocysts approximately three to ten days after contamination, and they will continue to excrete T. gondii for between ten days to 2 weeks.
The other form of the infection, called a tachyzoite, can penetrate through the affected cat’s intestines and reproduce, eventually resulting in the parasite spreading to other parts of the body. With a strong immune system, the cat's immune system will inevitably kick in and force the infection into a dormant phase.
Cat poop is not the only way this awful parasite is shed. There are in fact a couple of different ways for humans to contract toxoplasmosis. The first is through eating undercooked meat tainted with the parasite; the second is through exposure to an infected cat's dookie. Common transmission methods related to these include not properly cleaning utensils used to cut raw meat; eating unwashed fruits or vegetables; through organ or blood donation from an infected person; and, most tragically, it can be passed from mother to child in the womb, often with catastrophic consequences.
This single-celled, microscopic protozoan parasite — the toxoplasma gondii parasite — is one of the most common parasites in existence, but that doesn't make it any less dangerous for some who will contract it. Most people who own cats will contract it at some point, and most will experience no symptoms, or only mild and flu-like symptoms at worst. But for those with weakened immune systems, and women who contract the parasite for the first time while pregnant — it can have horrible effects, especially for the unborn child.
People who are generally healthy with strong immune systems may experience symptoms such as fatigue, headache, fever, swollen lymph nodes, and muscle pain. However, for those unlucky enough to have weakened immune systems, especially chronic conditions like HIV or AIDS, the symptoms can be much worse. They might include loss of coordination, confusion, reduced vision or blurriness, inflammation of the heart, lungs, and encephalitis (inflammation of the brain tissue). Some of these conditions can be fatal if left untreated.
Moreover, a study released earlier this year suggests there may be a correlation between repeated exposure to T. gondii and some types of cancer. Researchers analyzed the amount of antibodies in the blood, which can help determine the level of exposuse, and found a correlation between high exposure levels and the risk of developing glioma — a common and deadly form of brain cancer.
For our furry friends, the symptoms of a serious case are pretty similar. Cats with immunodeficincies like Feline Leukemia or Feline AIDS (FIV - Feline immunodeficiency virus) are more at risk. Symptoms include fatigue, vision problems, seizures, balance issues, diarrhea, loss of appetite, fever, ear twitching, and general behavioral changes.
Stay Away From Litterboxes When You're Pregnant:
If you've ever been pregnant, I'm sure you've been warned to let someone else shoulder the responsibility of cleaning your cat's litter box (what a tragedy, right?!). Some brush off that warning, but unless you're absolutely sure you've already had toxoplasmosis before, that's not a risk you should be willing to take. Again, most cat owners will contract it at some point and will never know, but congenital toxoplasmosis — which occurs when a pregnant woman passes the disease on to her child in utero — is a whole other beast.
Your baby is most at risk of infection in the third trimester (that's 28 weeks to 40 weeks pregnant), but the consequences can be even worse in the first trimester (zero to twelve weeks). Those exposed very early on are often miscarried or stillborn. Meanwhile, babies exposed in the later stages of pregnancy will likely live, but their quality of life could be greatly diminished. Symptoms might include, but are not limited to, jaundice, seizures, serious eye infections, an enlarged spleen and/or liver, and in some cases, hearing loss, blindness, and serious congenital issues such as brain damage, delayed intellectual development, and even death. What's even scarier is that the child may not show any symptoms of exposure at birth.
Your child will likely be safe if you had the infection more than 6 months before pregnancy. If you become reinfected, your baby may inherit your immunity. If you are concerned, there are blood tests that can detect whether your body ever developed antibodies to Toxoplasma, so see your doctor if you are planning on getting pregnant and have been exposed to many cats.
How Can I Minimize the Risk?
Cleaning up your cat's litter box every day is a good idea as the parasite lays dormant for 1 to 5 days after excretion
If you live alone, and having someone else scoop your cat's crap box isn't possible, but fret not, there are a few ways you can minimize your risk of contracting toxoplasma. For starters, always wear gloves and wash your hands after cleaning, you should clean out your cat's box every single day, and dispose of all waste immediately, as the parasite isn't immediately infectious (only 1 to 5 days after your cat excretes it), avoid strays and don't get a new cat while pregnant, keep your cat inside, and always wear gloves when gardening.
Center for Disease Control, also reommends following safe food practices, which include:
"Cook food to safe temperatures. A food thermometer should be used to measure the internal temperature of cooked meat. Color is not a reliable indicator that meat has been cooked to a temperature high enough to kill harmful pathogens like Toxoplasma. Do not sample meat until it is cooked. USDA recommends the following for meat preparation:"
For Whole Cuts of Meat (excluding poultry)
"Cook to at least 145° F (63° C) as measured with a food thermometer placed in the thickest part of the meat, then allow the meat to rest for three minutes before carving or consuming. *According to USDA, “A ‘rest time’ is the amount of time the product remains at the final temperature, after it has been removed from a grill, oven, or other heat source. During the three minutes after meat is removed from the heat source, its temperature remains constant or continues to rise, which destroys pathogens.”
For Ground Meat (excluding poultry)
"Cook to at least 160° F (71° C); ground meats do not require a rest time."
For All Poultry (whole cuts and ground)
"Cook to at least 165° F (74° C). The internal temperature should be checked in the innermost part of the thigh, innermost part of the wing, and the thickest part of the breast. Poultry do not require a rest time."
They also recommend the following:
- Freeze meat for several days at sub-zero (below 0° F) temperatures before cooking to greatly reduce chance of infection. *Freezing does not reliably kill other parasites that may be found in meat (like certain species of Trichinella) or harmful bacteria. Cooking meat to USDA recommended internal temperatures is the safest method to destroy all parasites and other pathogens.
- Peel or wash fruits and vegetables thoroughly before eating.
- Wash cutting boards, dishes, counters, utensils, and hands with soapy water after contact with raw meat, poultry, seafood, or unwashed fruits or vegetables.
- Avoid drinking untreated water.
- Do not drink unpasteurized goat’s milk.
- Do not eat raw or undercooked oysters, mussels, or clams (these may be contaminated with Toxoplasma that has washed into seawater).
Should you contract toxoplasmosis when pregnant, there are treatment options. Talk to your doctor and follow all recommendations.