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Clinical Features:
Acquired infection with
Toxoplasma in immunocompetent persons is generally an asymptomatic infection.
However, 10% to 20% of patients with acute infection may develop cervical lymphadenopathy and/or a flu-like illness.
The clinical course is benign and self-limited; symptoms usually resolve within a few months to a year.
Immunodeficient patients often have central nervous system (CNS) disease but may have
retinochoroiditis, or pneumonitis.
In patients with AIDS, toxoplasmic encephalitis is the most common cause of intracerebral mass lesions and is thought to be caused by reactivation of chronic infection.
Toxoplasmosis in patients being treated with immunosuppressive drugs may be due to either newly acquired or reactivated latent infection.
Congenital toxoplasmosis results from an acute primary infection acquired by
the mother during pregnancy. The incidence and severity of congenital
toxoplasmosis vary with the trimester during which infection was acquired.
Because treatment of the mother may reduce the incidence of congenital infection and reduce sequelae in the infant, prompt and accurate diagnosis is important.
Most infants with subclinical infection at birth will subsequently develop signs or symptoms of congenital toxoplasmosis unless the infection is treated.
Ocular Toxoplasma infection, an important cause of retinochoroiditis in the United States, is frequently a result of congenital infection.
Patients are often asymptomatic until the second or third decade of life, when lesions develop in the eye.
Laboratory Diagnosis:
The diagnosis of
toxoplasmosis may be documented by:
- Observation of parasites in
patient specimens, such as bronchoalveolar lavage material from immunocompromised
patients, or lymph node biopsy.
- Isolation of parasites from
blood or other body fluids, by intraperitoneal inoculation into mice or tissue culture.
The mice should be tested for the presence of Toxoplasma organisms in the
peritoneal fluid 6 to 10 days post inoculation; if no organisms are found, serology can be
performed on the animals 4 to 6 weeks post inoculation.
- Detection of parasite genetic
material by PCR, especially in detecting congenital infections in utero.
- Serologic testing is the
routine method of diagnosis, because the techniques described above are technically
complex and generally not rewarding.
Diagnostic findings
Treatment:
Treatment is not needed for a healthy person who is not pregnant.
Symptoms will usually go away within a few weeks. Treatment may be
recommended for pregnant women or persons who have weakened immune
systems.
See recommendations in The Medical Letter for complete information.
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