title: Improvement of a direct agglutination test for field studies of visceral leishmaniasis.
abstract: To increase the potential for the wide-scale application of our direct agglutination test for visceral leishmaniasis, modifications in the components and procedures were introduced. Supplementation with 0.056 M citrate of the suspension medium stabilized the antigen for 9 weeks at 37 degrees C. To circumvent the need for cooling systems in the field, 0.2% (wt/vol) gelatin was added to the serum diluent instead of fetal bovine serum, with reliable results. Specificity and sensitivity were improved by the incorporation of 0.1 M 2-mercaptoethanol in samples with borderline titers. The test could be performed on samples of whole blood; thus the difficulties of preparation and storage of serum, plasma, or filter paper blood are avoided. For mass screening programs, a single serum dilution of 1:6,400 could be employed, contributing to a further reduction in test expenses. Sera from different geographical areas showed equal reactivities in this direct agglutination test despite the nonhomologous Leishmania donovani antigens used.
authors.affiliation: N.H. Swellengrebel Laboratory of Tropical Hygiene, Royal Tropical Institute, Amsterdam, The Netherlands.
authors.forename: A
authors.initials: A
authors.lastname: el Harith
authors.forename: A H
authors.initials: AH
authors.lastname: Kolk
authors.forename: J
authors.initials: J
authors.lastname: Leeuwenburg
authors.forename: R
authors.initials: R
authors.lastname: Muigai
authors.forename: E
authors.initials: E
authors.lastname: Huigen
authors.forename: T
authors.initials: T
authors.lastname: Jelsma
authors.forename: P A
authors.initials: PA
authors.lastname: Kager
mesh_terms: D000293:Adolescent; D000328:Adult; D000372:Agglutination Tests; D000818:Animals; D000913:Antibodies, Protozoan / Q000032:analysis; D000953:Antigens, Protozoan; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007893:Leishmania donovani / Q000276:immunology; D007898:Leishmaniasis, Visceral / Q000175:diagnosis*; D008297:Male; D051379:Mice; D008875:Middle Aged; D011237:Predictive Value of Tests
chemical_list: D000913:Antibodies, Protozoan; D000953:Antigens, Protozoan