toxoplasmosis

Disease caused by the protozoan parasite Toxoplasma gondii, which can produce abortion in sheep, encephalitis in mink, and a variety of syndromes in humans. Prenatally acquired human infection can result in the presence of abnormalities such as microcephalus or hydrocephalus at birth, the development of jaundice with hepatosplenomegaly or meningoencephalitis in early childhood, or the delayed appearance of ocular lesions such as chorioretinitis in later childhood. Postnatally acquired human infections typically remain subclinical; if clinical disease does occur, symptoms include fever, lymphadenopathy, headache, myalgia, and fatigue, with eventual recovery, except in the immunocompromised patient where fatal encephalitis often develops.

- acquired t. in adults a form of t. that may result in fever, encephalomyelitis, chorioretinopathy, maculopapular rash, arthralgia, myalgia, myocarditis, and pneumonitis; a lymphadenopathic form seems to be more prevalent in adults, and such persons may manifest fever, lymphadenopathy, malaise, and headache, a form frequently found in patients with AIDS.

- congenital t. t. apparently resulting from parasites in an infected mother being transmitted in utero to the fetus, observed as three syndromes: 1) acute : most of the organs contain foci of necrosis in association with fever, jaundice, hydrocephaly, encephalomyelitis, pneumonitis, cutaneous rash, ophthalmic lesions, hepatomegaly, and splenomegaly; 2) subacute : most of the lesions are partly healed or calcified, but those in the brain and eye seem to remain active, inasmuch as chorioretinitis is observed in more than 80% of diseased infants; 3) chronic : usually not recognized during the newborn period, but chorioretinitis and cerebral lesions may be detected weeks to years later.

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toxo·plas·mo·sis -.plaz-'mō-səs n, pl -mo·ses -.sēz infection with or disease caused by a sporozoan of the genus Toxoplasma (T. gondii) that invades the tissues and may seriously damage the central nervous system esp. of infants

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n.

a disease of mammals and birds caused by the protozoan Toxoplasma gondii, which is usually transmitted to humans through ingesting undercooked meat or cat faeces. Generally symptoms are mild (swollen lymph nodes and an influenza-like illness), but the disease can be serious in immunocompromised patients. Infection usually confers lifelong immunity. If caught during pregnancy it can cause congenital toxoplasmosis in the unborn baby. Although most babies are unaffected or have very mild disease, some can have severe malformations of the skull and eyes or active infection in the liver. It can also cause stillbirth. Infection can be detected by blood tests in the mother; if the diagnosis is confirmed, the mother can be treated with spiramycin.

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tox·o·plas·mo·sis (tok″so-plaz-moґsis) [toxo- + plasma + -osis] infection by the protozoon Toxoplasma gondii, transmitted in oocysts in the feces of cats (the definitive host), usually by contaminated soil, exposure to feces, tissue cysts in infected meat, or tachyzoites in blood. Most human infections are asymptomatic; when symptoms do occur, they are often a mild disease resembling mononucleosis. Occasionally toxoplasmosis becomes a fulminating, disseminated disease, usually in an immunocompromised patient or a fetus infected transplacentally; this may cause extensive damage to the brain, eyes, skeletal muscles, heart, liver, or lungs. See also toxoplasmic meningoencephalitis and toxoplasmic chorioretinitis. Chorioretinitis may occur with any form but is most often a late sequel of the congenital type. In domestic animals toxoplasmosis may be any of several nonfatal conditions such as a type of infectious abortion in ewes.