Studies on Mediterranean leishmaniasis. IV. The leishmanin skin test in cutaneous leishmaniasis.

The leishmanin skin test was used in four different areas of the Italian Adriatic coast (Emilia Romagna, Marche, San Marino and Abruzzi), old endemic areas for cutaneous leishmaniasis. The test was found to be postitive in 80% of past infections, the 20% negative reactions being found in those who had been infected 20 or more years before. In the old endemic area of Teramo there was increasing positivity with age, with a sharp rise in the over 30 years age group suggesting that there had been a sudden break in transmission 30 years ago, coinciding with the DDT campaign of 1944-45. In San Marino in the past overt infection had occurred in a number of small microfoci, centred on houses surrounded by a larger number of inapparent infection. Control studies on a number of infectious and non-infectious diseases were all negative, and there was no relationship between tuberculin and leishmanin sensitivity.