Several serologic surveys have reported the prevalence of Toxoplasma dye-test antibodies or skin sensitivity among population groups in different geographic areas. A summary and interpretation of a number of these papers are given by Jacobs (1956a), and Feldman and Miller (1956) present a review of their own findings. A discussion of survey data in relation to climate is given by Gibson and Coleman (1958).
The original aims of the work to be reported here were two: First, previous studies on vegetarians had shown an apparently lower prevalence of positive reactions than might have been expected in a group of comparable age from the general population, but these vegetarian serums were of such diverse geographic origin that there was no really comparable control group (Jacobs, 1957). Since Trinidad has a sizeable population of East Indians, we hoped (in vain) that we might be able to obtain representative groups of vegetarian Hindus and other populations in the same locale for an adequate comparison.