Leishmanin test survey in an endemic village of Indian kala-azar near Calcutta

A leishmanin test survey was carried out in a village during the declining phase of an outbreak of Indian kala-azar. One hundred and fifty of the total population of 220, including 25 clinically cured cases of kala-azar, were available for this study. Nineteen per cent (24 of 125) of the otherwise normal subjects showed delayed hypersensitivity to leishmanin antigen. The majority of these were household contacts of kala-azar patients, and the remainder came from the close neighbourhood. This may support the view that microfoci are of importance in the spread of the disease. The age-specific profile of leishmanin positivity was found to increase steadily, attaining a high level in older age groups.