Print this page    •   Back to Web version of article

You Can Prevent Toxo

June 21, 2007

What is toxo?

  • Toxo can be prevented.
  • People with HIV infection should be tested for toxo.
  • Toxo usually causes illness in people whose CD4 count is below 100.
  • TMP-SMX, also known as Bactrim, Septra, or Cotrim,* is the best drug for preventing toxo.
Toxoplasmosis [tox-o-plaz-MO-sis], or "toxo," is a common infection among people with HIV and AIDS. It usually affects the central nervous system, including the brain. Many people infected with toxo have no symptoms. However, people with HIV or AIDS often get ill from toxo infection.

What are the symptoms of toxo-related illness?

The most common symptoms of toxo-related illness are headache, confusion, and fever. Other symptoms include seizures, poor coordination, and nausea.

How is toxo spread (or transmitted)?

Toxo can be spread in two ways: 1) by eating undercooked meat; and 2) through contact with infected cat stool.

How can I protect myself from toxo infection?

What happens when someone with HIV has toxo infection?

What happens when someone with HIV has toxo infection?When someone is infected with toxo, it hides in inactive tissue eggs (or cysts), usually in the brain or muscles. These infections stay inactive as long as the infected person's immune system is strong. However, when HIV weakens the immune system, toxo can cause illness. In the United States, from 15 percent to 40 percent of people with HIV infection have been infected with toxo and probably have tissue cysts. Up to half of all persons with AIDS who have toxo infection and a CD4 count under 100 get toxo-related illness.

What should I do to prevent an inactive toxo infection from becoming active?

What happens when someone with HIV has toxo infection?The most important thing you can do is to get the best care you can for your HIV infection. Take your antiretroviral medicine just the way your doctor tells you to. If you get sick from your medicine, call your doctor for advice. Toxo most affects HIV-infected people whose CD4 counts are below100. If you were not tested for toxo when you were tested for HIV, ask your doctor to test you for toxo at your next appointment.

If you have toxo infection and your CD4 count falls below 100, your doctor will prescribe TMP-SMX to prevent illness. TMP-SMX is also used to prevent Pneumocystis carinii pneumonia (PCP). If you can't take TMP-SMX, other drugs are available for toxo and PCP.

If I have had toxo-related illness, can I get it again?

Yes. If you have had toxo-related illness, you will need to take drugs for the rest of your life to prevent getting it again.

For more information, call

Free referrals and information:

CDC-INFO 1-800-CDC-INFO (232-4636) TTY: 1-888-232-6348 In English, en Espa?ol 24 Hours/Day

Free materials:

CDC National Prevention Information Network
(800) 458-5231
1-301-562-1098 (International)
P.O. Box 6003
Rockville, MD 20849-6003

Free HIV/AIDS treatment information:

(800) 448-0440
Project Inform
(800) 822-7422

Drugs undergoing clinical trials:

(800) 448-0440

Social Security benefits:

Social Security Administration
(800) 772-1213
(You also may request a personal earnings and benefit estimate statement to help you estimate the retirement, disability, and survivor benefits payable on your Social Security record.)
Child Health Insurance Program
1-877 KIDS NOW (1-877-543-7669)
CDC Division of HIV/AIDS Prevention Internet address:

Additional brochures in the Opportunisitic Infections Series:

* Use of trade names does not imply endorsement by the United States Department of Health and Human Services.

This article was provided by U.S. Centers for Disease Control and Prevention. You can find this article online by typing this address into your Web browser:

General Disclaimer: is designed for educational purposes only and is not engaged in rendering medical advice or professional services. The information provided through should not be used for diagnosing or treating a health problem or a disease. It is not a substitute for professional care. If you have or suspect you may have a health problem, consult your health care provider.