The primary symptoms of toxoplasmosis typically include a persistent headache, fever, extreme fatigue, and shortness of breath. However, most healthy individuals do not experience any noticeable signs because their immune systems effectively manage the parasite.
These symptoms are significantly more common in individuals with weakened immune systems due to chronic illness, other infections, or specific medications. People who have recently undergone an organ transplant are also at a higher risk of developing symptomatic infections.
Severe complications often arise in patients who do not receive timely or appropriate medical treatment. The parasite can remain dormant in body tissues for long periods and reactivate when the immune system becomes compromised.
Common symptoms
The most frequent signs of a toxoplasmosis infection include:
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Persistent headache
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Fever
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Excessive fatigue
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Muscle aches
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Sore throat
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Shortness of breath
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Mental confusion
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Seizures
The severity of these symptoms depends largely on the strength of the patient's immune system. For instance, neurological symptoms like confusion and seizures are much more prevalent in those with severely weakened immunity.
Symptoms in babies
Congenital toxoplasmosis occurs when the parasite crosses the placenta to infect the developing fetus. The resulting symptoms vary based on when the infection happened during the pregnancy and may include:
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Frequent seizures
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Microcephaly (abnormally small head)
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Hydrocephalus (fluid buildup in the brain)
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Jaundice (yellowing of the skin and eyes)
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Hair loss
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Intellectual disabilities
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Eye inflammation
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Blindness
Infections occurring during the first trimester carry a lower risk of transmission but often result in the most severe birth defects or pregnancy loss. Conversely, infections acquired during the third trimester are more likely to be passed to the baby, though these infants often appear healthy at birth and only develop symptoms later during childhood or adolescence.
Confirming a diagnosis
To confirm an infection, healthcare providers evaluate a patient's symptoms alongside their medical history and lifestyle habits. Diagnostic testing usually begins with a complete blood count (CBC) and a C-reactive protein (CRP) test to identify general markers of infection.
Because the parasite often lives within body tissues rather than the bloodstream, direct identification can be difficult. Therefore, doctors primarily rely on specialized blood tests that detect specific antibodies produced by the immune system to fight T. gondii.
The diagnosis is typically confirmed by measuring IgG and IgM antibody levels. These levels rise quickly during an active infection, and a physician will correlate these lab results with the patient's physical symptoms to reach a definitive conclusion.