HIV and Toxoplasmosis

Posted by Pozziepinoy on 8:44 AM
These past weeks I have been assisting PLHIV's with toxoplasmosis. I remembered having tested a year ago on it and the result showed that I am not immune to it, meaning I am not exposed to it. When I was still a patient of PGH-SAGIP, the doctor resident said that almost all Filipinos are exposed to it because she said that we are used to playing in dirt or soil or we eat raw food or we love playing with cats. Well even though I don't have it, I am pretty careful so I won't acquire it even with my rebounded immune system.



What is Toxoplasmosis?

Toxoplasmosis is a paralytic disease caused by the protozoan Toxoplasma gondii. The parasite will infect most genera of warm-blooded animals, including humans, but the primary host is the felid (cat) family. The parasite spreads by the ingestion of infected meat or the feces of an infected cat, or by vertical transmission from mother to fetus.

Toxoplasmosis is considered to be a leading cause of death attributed to foodborne illness in the United States. More than 60 million men, women, and children in the U.S. carry the Toxoplasma parasite, but very few have symptoms because the immune system usually keeps the parasite from causing illness.

Toxoplasmosis is the leading cause of focal central nervous system (CNS) disease in AIDS. CNS toxoplasmosis in HIV-infected patients is usually a complication of the late phase of the disease.

Typically, lesions are found in the brain and their effects dominate the clinical presentation. Rarely, intraspinal lesions need to be considered in the differential diagnosis of myelopathy.

The decision to treat a patient for CNS toxoplasmosis is usually empiric. Primary therapy is followed by long-term suppressive therapy, which is continued until antiretroviral therapy can raise CD4+ counts above 200 cells/µL.

Prognosis is guarded. Patients may relapse because of noncompliance or increasing dose requirements.

Signs and Symptoms?

During acute toxoplasmosis, symptoms are often influenza-like: swollen lymph nodes, or muscle aches and pains that last for a month or more. Rarely, a patient with a fully functioning immune system may develop eye damage from toxoplasmosis. Young children and immunocompromised patients, such as those with HIV/AIDS, those taking certain types of chemotherapy, or those who have recently received an organ transplant, may develop severe toxoplasmosis. This can cause damage to the brain (encephalitis) or the eyes (necrotizing retinochoroiditis).


Persons with compromised immune systems may experience severe symptoms if infected with Toxoplasma while immune suppressed. For example, a person who is HIV-infected and who has reactivated Toxoplasma infection can have symptoms that include fever, confusion, headache, seizures, nausea, and poor coordination. Persons who acquire HIV infection and were not infected previously with Toxoplasma are more likely to develop a severe primary infection.

Immunocompromised persons who were infected with Toxoplasma at some point before they become immunosuppressed are particularly at risk for developing a relapse of toxoplasmosis.

Toxoplasma infection can reactivate in immunocompromised pregnant women who were infected with Toxoplasma before their pregnancy, and this can lead to congenital infection.

Diagnosis

The diagnosis of toxoplasmosis is typically made by serologic testing. A test that measures immunoglobulin G (IgG) is used to determine if a person has been infected. If it is necessary to try to estimate the time of infection, which is of particular importance for pregnant women, a test which measures immunoglobulin M (IgM) is also used along with other tests such as an avidity test.

Treatment:

Persons with compromised immune systems need to be treated until they have improvement in their condition. For AIDS patients, continuation of medication for the rest of their lives may be necessary, or for as long as they are immunosuppressed.

In patients in whom brain imaging shows multiple lesions, whether serologic results are negative or positive, antitoxoplasmosis therapy should be initiated. In cases of impending herniation, an open biopsy with decompression is indicated. Corticosteroid treatment may be warranted in cases of impending brain herniation. However, their use may complicate the interpretation of a response to antitoxoplasmosis therapy.

Empiric antimicrobial therapy must be comprehensive and should cover all likely pathogens in the context of the clinical setting. Antibiotic combinations usually are recommended to circumvent resistance from bacterial subpopulations (which may be resistant to one of the antibiotic components) and to provide additive or synergistic effect.
Standard therapy consists of pyrimethamine, sulfadiazine, and folinic acid in combination. 

 Trimethoprim-sulfamethoxazole (TMP-SMZ) can be used as an alternative regimen. A Cochrane data base review failed to find a significant difference between standard therapy and TMP-SMZ. Clindamycin can be used in patients allergic to sulfa drugs. Effective antiretroviral therapy is equally important.

With antibiotic therapy, 74% of patients improve by day 7, and 91% improve by day 14. Imaging studies are performed every 4-6 weeks until complete resolution of the lesion or stabilization after partial resolution.

Primary therapy is given for 6 weeks, followed by long-term suppressive therapy at reduced doses, with the duration determined by response to highly active antiretroviral therapy (HAART). The long-term suppressive therapy can be discontinued in patients with persistent elevation of CD4+ counts greater than 200 cells/µL and resolution of lesions on MRI.

HIV and Toxoplasmosis:

If you have a weakened immune system, it is important to talk to your health care provider about getting a blood test to determine if you have been infected with Toxoplasma gondii.
If you have HIV infection and have not been infected previously with T. gondii, you are more likely to develop a severe infection if you become infected. Even if you have a prior infection, with the development of immunodeficiency you may experience a relapse. This relapse can result in symptoms such as headache, confusion, poor coordination, nausea or vomiting, and fever. You may also experience seizures.

Prevention and Control:

Reduce Risk from Food

To prevent risk of toxoplasmosis and other infections from food:
  • Cook food to safe temperatures. A food thermometer should be used to measure the internal temperature of cooked meat. 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.
    • 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), and for whole poultry 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."
  • Freeze meat for several days at sub-zero (0° F) temperatures before cooking to greatly reduce chance of infection.
  • Peel or wash fruits and vegetables thoroughly before eating
  • Wash counter tops carefully.
  • Wash cutting boards, dishes, counters, utensils, and hands with hot soapy water after contact with raw meat, poultry, seafood, or unwashed fruits or vegetables.
Reduce Risk from the Environment

To prevent risk of toxoplasmosis from the environment:
  • Avoid drinking untreated drinking water.
  • Wear gloves when gardening and during any contact with soil or sand because it might be contaminated with cat feces that contain Toxoplasma. Wash hands with soap and warm water after gardening or contact with soil or sand.
  • Teach children the importance of washing hands to prevent infection.
  • Keep outdoor sandboxes covered.
  • Have someone else clean the litter box. 
  • Feed cats only canned or dried commercial food or well-cooked table food, not raw or undercooked meats.
  • Change the litter box daily If you own a cat. The Toxoplasma parasite does not become infectious until 1 to 5 days after it is shed in a cat's feces. If you are pregnant or immunocompromised:
    1. Avoid changing cat litter if possible. If no one else can perform the task, wear disposable gloves and wash your hands with soap and warm water afterwards.
    2. Keep cats indoors.
    3. Do not adopt or handle stray cats, especially kittens. Do not get a new cat while you are pregnant.

As PLHIV's, we should always be on the lookout for opportunistic infections such as toxoplasmosis. We should never let our guard down as infections can complicate or health, all the time.

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