Description

• Acute self-limited infection if immunocompetent
• Acute symptomatic or reactivated latent infection in immunocompromised persons
• Congenital toxoplasmosis (acute primary infection during pregnancy)
• Ocular toxoplasmosis

• The earlier fetal infection occurs, the more severe
• Risk of perinatal death is 5% if infected in 1st trimester

• Pregnant immunocompromised and HIV-infected women should undergo serologic testing (1)[C].
• Seronegative pregnant women should emphasize prevention.
• Serologic testing during pregnancy is controversial.

Epidemiology

• Birth prevalence of congenital toxoplasmosis in the US: 10–100/100,000 live births
• Predominant sex: Male > Female

• In the US, 11% aged 6–49 years are seropositive.
• Age-adjusted prevalence in the US is 22.5%.
• Seroprevalence among women in the US is 15%.

Risk Factors

• Immunocompromised states, including HIV infection with CD4 cell count <100/μL
• Primary infection during pregnancy; risk of transmitting infection to the fetus increases with gestational age at seroconversion, although transmission in the 1st trimester is associated with more severe consequences.
• Chronically infected pregnant women who are immunocompromised have an increased risk of congenital toxoplasmosis.

Genetics
Human leukocyte antigen (HLA) DQ3 is a genetic marker of susceptibility in AIDS.

General Prevention

Prevention is important in seronegative pregnant women and immunodeficient patients:

• Avoid eating undercooked meat: Cook to 152°F (66°C) or freeze for 24 hours at ≤–12°C.
• Avoid drinking unfiltered water.
• Wash produce.
• Strict hand hygiene after touching soil.
• Wear gloves and wash hands after handling handling raw meat or cat litter.
• Avoid eating shellfish; (Toxoplasma cysts)

Pathophysiology

Transmission to humans:

• Ingestion of raw or undercooked meat, food, or water containing tissue cysts or oocytes; usually from soil contaminated with feline feces
• Transplacental to fetus from infected mother; risk of transmission is 30% on average
• Blood product transfusion and solid-organ transplantation

Etiology

T. gondii, an obligate intracellular sporozoan

Commonly Associated Conditions

• Chorioretinitis; self-limiting, febrile lymphadenopathy; mononucleosislike illness
• A statistically significant association exists between schizophrenia and several infectious agents (including T. gondii); clinical implications are unclear (2).