title: rK39 enzyme-linked immunosorbent assay for diagnosis of Leishmania donovani infection.
abstract: The rK39 enzyme-linked immunosorbent assay (ELISA) was compared with the direct agglutination test (DAT) for Leishmania donovani infection in the Sudan. rK39 ELISA proved more sensitive than DAT in diagnosis of kala-azar (93 and 80%, respectively); both tests may remain positive up to 24 months after treatment. For patients with post-kala-azar dermal leishmaniasis and individuals with subclinical infection, rK39 ELISA performed as well as DAT but could detect infection 6 months earlier in approximately 40% of patients. Conversion in DAT and rK39 ELISA also occurred in leishmanin skin test (LST)-positive individuals, suggesting active parasite replication (rK39 is an amastigote antigen) in these presumably immune individuals. In contrast to DAT, rK39 ELISA also detected infection in randomly selected LST-positive individuals (in four of six) and endemicity (LST-negative) controls (in one of five). rK39 ELISA appears more sensitive than DAT and may prove an important tool in epidemiological studies.
authors.affiliation: Institute of Endemic Diseases, University of Khartoum, Khartoum, Sudan.
authors.forename: E E
authors.initials: EE
authors.lastname: Zijlstra
authors.forename: N S
authors.initials: NS
authors.lastname: Daifalla
authors.forename: P A
authors.initials: PA
authors.lastname: Kager
authors.forename: E A
authors.initials: EA
authors.lastname: Khalil
authors.forename: A M
authors.initials: AM
authors.lastname: El-Hassan
authors.forename: S G
authors.initials: SG
authors.lastname: Reed
authors.forename: H W
authors.initials: HW
authors.lastname: Ghalib
mesh_terms: D000293:Adolescent; D000328:Adult; D000372:Agglutination Tests / Q000379:methods; D000818:Animals; D000913:Antibodies, Protozoan / Q000097:blood; D000953:Antigens, Protozoan / Q000276:immunology*; D002648:Child; D002675:Child, Preschool; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods*; D006801:Humans; D007893:Leishmania donovani / Q000276:immunology*; D007898:Leishmaniasis, Visceral / Q000175:diagnosis* / Q000453:epidemiology / Q000276:immunology; D008875:Middle Aged; D015800:Protozoan Proteins / Q000276:immunology*; D016036:Seroepidemiologic Studies; D013397:Sudan / Q000453:epidemiology
chemical_list: D000913:Antibodies, Protozoan; D000953:Antigens, Protozoan; D015800:Protozoan Proteins; C079253:K39 antigen, Leishmania