Toxoplasmosis is a zoonotic disease caused by infection with the parasite Toxoplasma gondii. The severity of the illness varies, but congenital infections are particularly severe and often involve central nervous system symptoms.

bubble_chart Clinical Manifestations

1. Congenital toxoplasmosis: The infection is systemic, but the main manifestations are widespread meningoencephalitis and meningomyelitis. After fetal infection, it can lead to late abortion, premature labor, or stillbirth. The disease may manifest at birth or shortly after, presenting with fever, rash, jaundice, vomiting, abdominal distension and fullness, diarrhea, and mucoid bloody stools. Symptoms also include shortness of breath, cough, cyanosis, lymphadenopathy, and hepatosplenomegaly. Meningitis and meningoencephalitis, hydrocephalus, microcephaly, motor or intellectual disabilities, as well as intracranial calcifications and chorioretinitis are common. Cerebrospinal fluid may appear yellow with increased cells and protein. Affected infants may die within days or weeks after birth. Survivors may experience seizures, intellectual disability, and chorioretinitis.
2. Acquired toxoplasmosis: In severe cases, the onset is acute, with high fever, severe headache, muscle pain, rash, facial flushing, conjunctival congestion, drowsiness, unconsciousness, and systemic toxic symptoms. Hepatosplenomegaly and lymphadenopathy are present. Symptoms related to damage to the eyes, brain, kidneys, heart, or lungs may also occur. Mild cases may be asymptomatic or present with fatigue, fever, and lymphadenopathy, with symptoms typically resolving within days or weeks. It is often caused by latent or acquired infections and is more common in immunocompromised patients or those receiving immunosuppressive therapy.

bubble_chart Auxiliary Examination

1. Blood picture: White blood cells are normal or slightly elevated, with an increase in lymphocytes and eosinophils, and atypical lymphocytes may be seen.
2. Cerebrospinal fluid: Pressure is normal or slightly elevated, sometimes appearing yellow, with increased protein, normal or decreased sugar, decreased chloride, and cell count around 50×10⁶/L.
3. Liver function tests: Bilirubin and transaminase may be elevated when the liver is damaged.
4. Direct examination of the patient's body fluids (e.g., blood, urine, cerebrospinal fluid, sputum, bone marrow) or tissue (e.g., enlarged lymph nodes, liver, spleen) biopsy, using Wright or Giemsa staining to identify crescent-shaped Toxoplasma trophozoites can confirm the diagnosis, but they are often difficult to find.
5. Animal inoculation for parasite isolation: Process the patient's body fluids or biopsy tissue and inoculate them into the peritoneal cavity or brain of mice. After lesions appear, prepare smears or sections of the animal's peritoneal fluid or brain tissue for staining to identify trophozoites. If still negative, serial passage inoculation 2–3 times can enhance virulence for further testing to confirm the diagnosis.
6. Artificial culture: First, use monkey kidney or pig kidney cells for monolayer cell culture, then inoculate the test specimen. Toxoplasma can rapidly multiply in the cells, yielding a positive result.
7. Indirect hemagglutination test: A titer of 1:64 indicates past infection, 1:256 indicates recent infection, and 1:1024 indicates active infection. Simultaneous absorption testing can exclude most titers of <1:200的假陽性反應。
8. Other enzyme-linked immunosorbent assays, radioimmunoassays, and indirect fluorescent antibody tests can also aid in diagnosis.

1. Fundus examination: Helps diagnose ocular toxoplasmosis presenting as retinochoroiditis.
2. X-ray examination: Chest X-rays can provide clues for heart or lung damage. Skull X-rays may reveal intracranial calcifications or skull abnormalities.
3. Cranial CT or MRI can aid in diagnosing central nervous system lesions.

bubble_chart Diagnosis

Epidemiological History Toxoplasmosis is widely distributed around the world. Many animals such as pigs, sheep, dogs, cats, and birds are infected with it. Therefore, consuming undercooked meat, milk, eggs, etc., drinking contaminated water, or close contact with livestock, cats, dogs, rabbits, etc., can lead to infection. For suspected cases of congenital toxoplasmosis, detailed inquiries should be made into the mother's infection history and pregnancy history.

bubble_chart Treatment Measures

1. Sulfadiazine: The dose is 100-150mg/(kg·d), divided into 2-3 oral doses, taken continuously for 10-14 days, with a 10-day interval before repeating the course. Sulfamethoxazole can also be used, with a dose of 40-80mg/(kg·d), divided into 2 doses, following the same treatment course as above.
2. Pyrimethamine: The dose is 1mg/(kg·d), divided into 2 oral doses, adjusted to 0.5mg/(kg·d) after 2-4 days, with a maximum daily dose not exceeding 25mg. The treatment course is 10-14 days, with a 10-day interval before repeating the course. The above two drugs are best used in combination, with both doses reduced to half. Since pyrimethamine can suppress bone marrow hematopoiesis, monitor white blood cell changes during medication, and yeast and folic acid can be administered simultaneously.
3. Acetylspiramycin: The dose is 30-40mg/(kg·d), divided into 3-4 oral doses, with a treatment course of 1 month. This drug can cross the placenta, and infected pregnant women taking it can reduce the infection rate of congenital toxoplasmosis.

bubble_chart Prevention

1. Pay attention to personal hygiene, dietary hygiene, and environmental hygiene.
2. Isolate and treat infected animals.
3. Women of childbearing age and pregnant women should undergo toxoplasmosis testing, and if infected, they should receive timely and adequate treatment. Especially, pregnant women should avoid contact with cats.