What precautions and treatments are recommended for pregnant women and immunocompromised individuals (immunocompromised individuals) to prevent and manage toxoplasmosis?

Toxoplasmosis Prevention and Management for Pregnant Women and Immunocompromised Individuals

Pregnant women and immunocompromised individuals should strictly avoid contact with cat litter, consume only thoroughly cooked meat, wash fruits and vegetables thoroughly, and practice good hand hygiene to prevent toxoplasmosis. For those already infected, specific medication regimens are essential to prevent serious complications.

Prevention Strategies

For Pregnant Women:

• Avoid changing cat litter or use gloves and wash hands thoroughly if unavoidable (BIII) 1
• Cook all meat thoroughly to temperatures sufficient to kill Toxoplasma (AI) 1
• Wash fruits and vegetables thoroughly before consumption 1
• Avoid gardening or wear gloves and wash hands afterward (BIII) 2
• Avoid contact with soil potentially contaminated with cat feces (BIII) 2
• Avoid raw/undercooked meat consumption (BII) 1
• Keep cats indoors to prevent them from hunting infected prey 1
• Avoid drinking untreated water directly from lakes or rivers (AIII) 2
• Avoid recreational water that may be contaminated with human or animal waste (BIII) 2

For Immunocompromised Individuals:

• Follow all prevention measures listed for pregnant women
• Avoid contact with cat feces and human feces (BIII) 2
• Avoid young pets (especially those <6 months old) or have veterinarian examine pet stool for Toxoplasma before contact (BIII) 2
• Avoid exposure to calves and lambs and premises where these animals are raised (BII) 2
• Avoid oral-anal sexual practices that might result in oral exposure to feces (BIII) 2

Screening Recommendations

For Pregnant Women:

• Routine universal screening is not recommended for low-risk pregnant women 3
• Serologic screening should be offered to pregnant women at high risk for primary Toxoplasma infection 3
• Women with ultrasound findings consistent with possible TORCH infection (intracranial calcification, microcephaly, hydrocephalus, etc.) should be offered screening 3

For Immunocompromised Individuals:

• HIV-infected individuals should be tested for IgG antibody to Toxoplasma when CD4+ counts fall below 100/μL to determine risk for toxoplasmic encephalitis (TE) (CIII) 2
• Immunosuppressed or HIV-positive women should be offered screening due to risk of reactivation and toxoplasmosis encephalitis (I-A) 3

Prophylaxis for Immunocompromised Individuals

Primary Prophylaxis:

• TMP-SMZ is the preferred regimen for prophylaxis against TE in HIV-infected patients with CD4+ counts <100 cells/μL who are seropositive for Toxoplasma (AII) 2
• Atovaquone may also provide protection (CIII) 2
• For patients who cannot tolerate TMP-SMZ or atovaquone, consider dapsone plus pyrimethamine (BIII) 2

Secondary Prophylaxis (after TE):

• Pyrimethamine plus sulfadiazine and leucovorin is highly effective (AI) 2
• For sulfa-intolerant patients: pyrimethamine plus clindamycin (BI), though only the pyrimethamine-sulfadiazine combination also protects against PCP (AII) 2
• Lifelong suppressive therapy is recommended to prevent relapse (AI) 2

Treatment Recommendations

For Pregnant Women:

• If acute infection is suspected, consider starting spiramycin immediately without waiting for confirmation (II-2B) 3
• If fetal infection is confirmed (usually by positive amniotic fluid PCR), offer pyrimethamine, sulfadiazine, and folinic acid combination (I-B) 3
• Pyrimethamine-containing regimens can be deferred until after pregnancy due to potential teratogenicity concerns (CIII) 2
• Pregnant women with primary toxoplasmic infection or active toxoplasmosis should be managed in consultation with specialists (BIII) 2

For Immunocompromised Individuals:

• Pyrimethamine plus sulfadiazine and leucovorin is the standard treatment regimen (AI) 4
• For patients who cannot tolerate sulfadiazine, pyrimethamine plus clindamycin is an alternative (BI) 2

Special Considerations

Children:

• TMP-SMZ for PCP prophylaxis also provides protection against toxoplasmosis 2
• Children >12 months who qualify for PCP prophylaxis but receive agents other than TMP-SMZ or atovaquone should have serologic testing for Toxoplasma antibody (BIII) 2
• Children with history of toxoplasmosis should receive lifelong prophylaxis to prevent recurrence (AI) 2

Congenital Toxoplasmosis:

• Infants born to women with serologic evidence of HIV and Toxoplasma infections should be evaluated for congenital toxoplasmosis (BIII) 2
• Amniocentesis should be offered to identify Toxoplasma in amniotic fluid by PCR if maternal primary infection is diagnosed (II-2B) 3
• Amniocentesis should not be performed before 18 weeks' gestation or less than 4 weeks after suspected maternal infection (II-2D) 3

Common Pitfalls and Caveats

• Many clinicians are unaware that some Toxoplasma IgM tests have high false-positive rates 5
• Suspected recent infection in pregnant women should be confirmed at a toxoplasmosis reference laboratory before intervention 3
• The Toxoplasma avidity test can help determine timing of infection in relation to pregnancy but is underutilized 5
• Non-pregnant women diagnosed with acute Toxoplasma infection should wait 6 months before attempting pregnancy 3
• Anti-toxoplasma treatment is not necessary for immunocompetent pregnant women with previous Toxoplasma infection (I-E) 3