In which of the following disease macula is most commonly involved:

Toxoplasmosis is a protozoan infection derived from cats in the form of oocyst which affects both retina and choroid to form chorioretinitis. In infants the infection is transmitted placenta and the fundus examination demonstrates bilateral and frequently multiple chorio-retinal lesions. The macular area is paicularly involved. Such infants are acutely ill with a history of seizures and may develop hydrocephalus, areas of calcification in brain and 'mental retardation.