Most pregnant women in the United States aren't routinely screened for toxoplasmosis, and most states don't screen infants for the infection. Without specific screening, toxoplasmosis is often difficult to diagnose because signs and symptoms, when they occur, are similar to those of more common illnesses, such as the flu and mononucleosis.
Testing during pregnancy
If your doctor suspects you have the infection, you may have blood tests that check for antibodies to the parasite. Antibodies are proteins produced by your immune system in response to the presence of foreign substances, such as parasites. Because these antibody tests can be difficult to interpret, the Centers for Disease Control and Prevention recommends that all positive results be confirmed by a laboratory that specializes in diagnosing toxoplasmosis.
What test results mean
Sometimes you may be tested early in the course of the disease before your body has a chance to produce antibodies. In that case, you may have a negative result, even though you're infected. To be certain, your doctor may recommend retesting several weeks later.
In most cases, a negative toxoplasmosis test result means you've never been infected and therefore aren't immune to the disease. If you're at high risk, you can take certain precautions so that you don't become infected.
A positive result could mean that you have an active infection, or it could mean that you were once infected and are immune to the disease. Additional tests can pinpoint when the infection occurred, based on the types of antibodies in your blood. This is especially important if you're pregnant or you have HIV/AIDS.
Testing your baby
If you are pregnant and have a current toxoplasmosis infection, the next step is to determine whether your baby also is infected. Tests your doctor may recommend include:
- Amniocentesis. In this procedure, which may be done safely after 15 weeks of pregnancy, your doctor uses a fine needle to remove a small amount of fluid from the fluid-filled sac that surrounds the fetus (amniotic sac). Tests are then performed on the fluid to check for evidence of toxoplasmosis. Amniocentesis carries a slight risk of miscarriage and minor complications, such as cramping, leaking fluid or irritation where the needle was inserted.
- Ultrasound scan. This test uses sound waves to produce images of your baby in the womb. A detailed ultrasound can't diagnose toxoplasmosis. It can however, show whether your baby has certain signs, such as fluid buildup in the brain (hydrocephalus). However, a negative ultrasound doesn't rule out the possibility of infection. For that reason, your newborn will need an examination and follow-up blood tests during the first year of life.
Testing in severe cases
If you've developed a life-threatening illness such as encephalitis, you may need one or more imaging tests to check for lesions or cysts in your brain. These include:
Magnetic resonance imaging (MRI). This test uses a magnetic field and radio (electromagnetic) waves to create cross-sectional images of your head and brain. During the procedure, you lie inside a large, doughnut-shaped machine that contains a magnet surrounded by coils that send and receive radio waves.
In response to the radio waves, your body produces faint signals that are picked up by the coils and processed into images by a computer. MRI is noninvasive and poses minimal risks to your health.
- Brain biopsy. In rare cases, especially if you don't respond to treatment, a neurosurgeon may take a small sample of brain tissue. The sample is then analyzed in a laboratory to check for toxoplasmosis cysts.
Most healthy people don't require toxoplasmosis treatment. But if you're otherwise healthy and have signs and symptoms of acute toxoplasmosis, your doctor may prescribe the following drugs:
Pyrimethamine (Daraprim). This medication, typically used for malaria, is a folic acid antagonist. It may prevent your body from absorbing the B vitamin folate (folic acid, vitamin B-9), especially when you take high doses over a long period. For that reason, your doctor may recommend taking additional folic acid.
Other potential side effects of pyrimethamine include bone marrow suppression and liver toxicity.
- Sulfadiazine. This antibiotic is used with pyrimethamine to treat toxoplasmosis.
Treating people with HIV/AIDS
If you have HIV/AIDS, the treatment of choice for toxoplasmosis is also pyrimethamine and sulfadiazine, with folinic acid (leucovorin). An alternative is pyrimethamine taken with clindamycin (Cleocin).
Treating pregnant women and babies
If you're pregnant and infected with toxoplasmosis, treatment may vary depending on where you receive medical care.
If infection occurred before the 16th week of pregnancy, you may receive the antibiotic spiramycin. Use of this drug may reduce your baby's risk of neurological problems from congenital toxoplasmosis. Spiramycin is routinely used to treat toxoplasmosis in Europe, but is still considered experimental in the United States.
If infection occurred after the 16th week of pregnancy, or if tests show that your unborn child has toxoplasmosis, you may be given pyrimethamine and sulfadiazine and folinic acid (leucovorin). Your doctor will help you determine the optimal treatment.
If your infant has toxoplasmosis or is likely to have it, treatment with pyrimethamine and sulfadiazine and folinic acid (leucovorin) is recommended. Your baby's doctor will need to monitor your baby while he or she is taking these medications.
Preparing for your appointment
You're likely to start by seeing your family doctor. If you're pregnant, you'll likely see your obstetrician, or you may be referred to a doctor who specializes in fetal health (perinatologist). In some instances, you may be referred to a doctor who specializes in infectious diseases.
Here's some information to help you get ready for your appointment.
What you can do
You may want to write a list that includes:
- Descriptions of your symptoms
- Information about medical problems you've had
- Information about the medical problems of your parents or siblings
- Medications and dietary supplements you take
- Questions you want to ask the doctor
For toxoplasmosis, some basic questions to ask your doctor include:
- What tests do I need?
- What treatments are available, and which do you recommend?
- What side effects might I expect from treatment?
- I'm pregnant. What effect will this have on my baby?
- I have other health problems. How can I manage them together?
- Are there brochures or other printed materials I can have? What websites do you recommend?
Don't hesitate to ask other questions, as well.
What to expect from your doctor
Your doctor is likely to ask you a number of questions, such as:
- When did your symptoms start?
- How severe are your symptoms?
- Have you recently consumed raw or undercooked meat?
- Do you own or care for a cat? Who changes the litter box?
- Do you wear gloves when gardening or working with soil?
- Do you have conditions or take medications that affect your immune system?
Oct. 13, 2020