Studies in Mediterranean leishmaniasis. 3. The leishmanin skin test in kala-azar.

Leishmanin skin testing was carried out in the Emilia-Romagna region of Northern Italy, the site of an outbreak of kala-azar in 1971-72, and in Catania, Eastern Sicily an old endemic focus of Mediterranean kala-azar. Nearly all the people who had recovered from kala-azar in the past gave positive skin tests. Active cases of kala-azar gave negative tests. There was a higher proportion of positive reactors amongst the household contacts and neighbours of cases of kala-azar than among the general population. Age specific leishmanin rates showed an increasing positive rate with age in Catania, comparable to those found in endemic areas in Kenya, but in the Emilia-Romagna area all age groups showed a high positivity rate suggesting a simultaneous exposure to infection. The age specific rates from Catania suggest an interruption in transmission 20-30 years ago. The leishmanin skin test is a useful tool for the study of the epidemiology of Mediterranean kala-azar.