title: The predictive validity of naturally acquired delayed-type hypersensitivity to leishmanin in resistance to Leishmania major-associated cutaneous leishmaniasis.
abstract: To accurately quantify the different outcomes of Leishmania major infection and to evaluate the fraction of zoonotic cutaneous leishmaniasis (ZCL) cases prevented by naturally acquired leishmanin skin test (LST) reactivity, a cohort of 470 children was followed up in 2 endemic foci, Remada and Dhiba, in southern Tunisia. During May 1997, before the ZCL emergence season, LST was performed, and results were reassessed 12 months later. Active case detection during the ZCL emergence season showed a high incidence of ZCL: 57.0% in Remada and 13.7% in Dhiba. The preventive fraction of ZCL conferred by LST reactivity increased proportionally with the reaction size before the emergence season, revealing a dose-response effect of approximately 70%. In addition, asymptomatic L. major infection appeared to be a significant form of natural immunization, particularly in the context of relatively low transmission. These findings may help in the design and evaluation of vaccines.
authors.affiliation: Laboratory of Epidemiology and Ecology of Parasitic Diseases, Institut Pasteur de Tunis, Tunis-Belvedere, Tunisia.
authors.forename: Afif
authors.initials: A
authors.lastname: Ben Salah
authors.forename: Hechmi
authors.initials: H
authors.lastname: Louzir
authors.forename: Sadok
authors.initials: S
authors.lastname: Chlif
authors.forename: Mourad
authors.initials: M
authors.lastname: Mokni
authors.forename: Amor
authors.initials: A
authors.lastname: Zaatour
authors.forename: Mohamed
authors.initials: M
authors.lastname: Raouene
authors.forename: Riadh Ben
authors.initials: RB
authors.lastname: Ismail
authors.forename: Koussay
authors.initials: K
authors.lastname: Dellagi
mesh_terms: D000293:Adolescent; D000818:Animals; D000953:Antigens, Protozoan / Q000276:immunology* / Q000378:metabolism; D002648:Child; D004306:Dose-Response Relationship, Immunologic; D005260:Female; D006801:Humans; D006968:Hypersensitivity, Delayed / Q000209:etiology*; D015994:Incidence; D018320:Leishmania major / Q000276:immunology / Q000378:metabolism / Q000472:pathogenicity*; D016773:Leishmaniasis, Cutaneous / Q000453:epidemiology / Q000276:immunology* / Q000469:parasitology / Q000635:transmission; D008297:Male; D011237:Predictive Value of Tests; D012882:Skin Tests; D014416:Tunisia / Q000453:epidemiology; D015047:Zoonoses / Q000453:epidemiology / Q000469:parasitology / Q000635:transmission
chemical_list: D000953:Antigens, Protozoan; C032127:leishmanin