Toxoplasmosis in People Who Have a Weak Immune System

What is toxoplasmosis, and how do you get it?

Toxoplasmosis (say: tox-oh-plaz-moh-sis) is an infection caused by a tiny parasite that lives in the intestines of animals such as cats and pigs.

You can get toxoplasmosis in the following ways:

  • By swallowing the parasite in cat litter or dirt that has cat droppings in it. This can happen if you put your hands to your mouth after gardening, cleaning a cat litter box or touching anything that has been in contact with cat droppings. Cats sometimes carry the parasite that causes toxoplasmosis.
  • By eating raw or partly cooked meat, especially pork, lamb or wild game.
  • By touching something, such as a cutting board or dish, that has been in contact with raw or undercooked meat and then putting your hands in or near your mouth.
  • By eating unwashed raw fruits and vegetables, or drinking water with the parasite in it.

People who have an organ transplant or a blood transfusion can also get toxoplasmosis. However, this rarely happens.

What are the symptoms of toxoplasmosis?

Most people have no symptoms because their immune system keeps the parasite from causing illness. Sometimes people who have toxoplasmosis experience flu-like symptoms, such as body aches, swollen lymph nodes, fever and headache. In people who have a weak immune system, toxoplasmosis can cause serious medical problems, such as damage to your eyes, lungs and brain. Your immune system can become weak for a number of reasons. Human immunodeficiency virus (HIV) infection leading to acquired immunodeficiency syndrome (AIDS) can weaken the immune system. So can some kinds of cancer chemotherapy or medicines that are taken after an organ transplant.

Toxoplasmosis is also a serious risk for women who are pregnant.

How do I know I have toxoplasmosis?

Routine screening for toxoplasmosis is not recommended. However, if you are at risk for toxoplasmosis because you have a weak immune system, your doctor might want you to have a blood test.

How is toxoplasmosis treated?

Toxoplasmosis is usually treated with antibiotics.

How can I keep from getting toxoplasmosis?

The following are some things you can do to protect yourself from getting toxoplasmosis:

  • Wear gloves when you work in the dirt. Cats often use gardens and sandboxes as litter boxes.
  • After outdoor activities, wash your hands with soap and warm water, especially before you eat or prepare food.
  • Use hot soapy water to clean cutting boards, dishes and other items after they have been in contact with raw meat, poultry, seafood, unwashed fruits and vegetables.
  • Cook meat until it is no longer pink in the center or until the juices run clear (160 degrees Fahrenheit on a meat thermometer). Do not taste meat before it is fully cooked.
  • When eating out, do not eat undercooked meat.
  • Avoid drinking untreated water, especially when traveling in less developed countries. Also avoid drinking unpasteurized (raw) goat's milk or unpasteurized products made from goat's milk.

I have a cat. Can I keep it?

Yes. If your immune system is weak, here are some things you can do to keep from getting toxoplasmosis:

  • Keep your cat indoors so that it does not pick up the toxoplasmosis parasite from the animals it hunts.
  • Feed your cat only dry or canned cat food. Like humans, cats can become infected with toxoplasmosis by eating raw or undercooked meat.
  • Do not bring a new cat into your house if the animal might have been an outdoor cat or might have been fed raw meat. Do not handle stray cats or kittens.
  • Have a person who is healthy and not pregnant change your cat's litter box. If you have to change the cat litter yourself, wear gloves while you do it. When you finish, wash your hands well with soap and warm water. Clean the litter box daily.

Cats only spread toxoplasmosis in their droppings for a few weeks in their lives (usually after they are first infected), so there is no benefit to having your cat's droppings tested for the toxoplasmosis parasite.

More Information

For more information talk to your doctor.

Other Organizations

  • CDC┬áToxoplasmosis Information


Written by editorial staff.

Congenital Toxoplasmosis by J Jones, M.D., M.P.H., A Lopez, M.H.S. and M Wilson, M.S. (American Family Physician May 15, 2003,

Reviewed/Updated: 04/08
Created: 06/04