Ocular toxoplasmosis

A large amount of research has been done on toxoplasmosis in the last 30 years, and the world-wide incidence of the infection, and its clinical manifestations, are recognized and documented in an extensive literature. New discoveries concerning the life-cycle of the organism (Frenkel, I970; Hutchison, Dunachie, Siim, and Work, I970) promise to solve many of the problems of the transmission of infection and will give added stimulus to epidemiological studies. In the field of ophthalmology the importance of toxoplasmosis is now established, but some problems still remain. The ocular lesions in infants with congenital toxoplasmosis are well recognized as pathogenic, but whether similar chorioretinal lesions in adults, although now acknowledged to be due to toxoplasmosis, result from recurrences of congenital infection or follow a postnatally acquired infection is still controversial. Other types of uveitis have been attributed to toxoplasmosis, and if this is correct it is important to recognize such cases. The present study attempts to clarify these problems by a review of the relevant literature supported by clinical studies in patients with uveitis. A further problem which will be discussed is whether congenital toxoplasmosis results from a chronic maternal infection or from one acquired during pregnancy: although this is not strictly an ophthalmological problem, ophthalmologists are often asked to advise on the prognosis for future pregnancies.