title: Co-reactivity of plasmodial histidine-rich protein 2 and aldolase on a combined immuno-chromographic-malaria dipstick (ICT) as a potential semi-quantitative marker of high Plasmodium falciparum parasitaemia.
abstract: The combined immuno-chromographic-malaria dipstick (ICT) for the rapid diagnosis of malaria detects both Plasmodium falciparum (P.f.)-specific, histidine-rich protein 2 (HRP-2) and a plasmodial aldolase expressed by all Plasmodium species pathogenic to humans. ICT was applied in 674 febrile returnees from malaria-endemic regions attending our Tropical Diseases Unit. Microscopy confirmed malaria in 69/674 cases, of whom 67/69 had returned from Africa or Madagascar, and 2/69 from the Caribbean. Monoparasitic P.f. infection occurred in 52/69, mixed infection was due to P.f.+ P. ovale (P.o.) in 3/69, and P.f.+P. malariae (P.m.) in 1/69 cases. Monoparasitic P. vivax (P.v.) infection occurred in 8/69 , P.o. in 3/69, and P.m. in 2/69 cases . Whereas a positive HRP-2 band on the test was a highly sensitive indicator for P.f. infection (52/52 patients; sensitivity 100%), this was not the case for a positive aldolase band (25/52 patients; sensitivity 48.1%). Sensitivity of aldolase band for non-falciparum plasmodia was even lower: aldolase was positive in only 3/8 (37.5%) of patients with vivax malaria, and in 0/5 cases with P.o.- or P.m. infection. Co-reaction of both bands occurred more frequently in patients with P.f. parasitaemia of > or =40,000/microl (20/25, 80.0%) as compared to patients with P.f. parasitaemia <40,000/microl (5/27, 18.5%; P<0.00005), and to patients with mixed infection (P.f.+ P.o., P.f.+ P.m.: 2/4, 50.0%; diff. n.s.). In our series, co-reaction of HRP-2 and aldolase indicated monoparasitic falciparum malaria with high P.f. parasitaemia, rather than mixed infection. Whereas the aldolase band is not a reliable qualitative marker for malaria, co-reaction of HRP-2 and aldolase band may have a potential for indicating high parasitaemia in falciparum malaria.
authors.affiliation: Tropenmedizinische Ambulanz, Klinik für Gastroenterologie, Hepatologie und Infektiologie, Universitätsklinikum Düsseldorf, Heinrich-Heine-Universität Düsseldorf, 40225 Düsseldorf, Germany. Joachim.Richter@med.uni-duesseldorf.de
authors.forename: Joachim
authors.initials: J
authors.lastname: Richter
authors.forename: Klaus
authors.initials: K
authors.lastname: Göbels
authors.forename: Irmela
authors.initials: I
authors.lastname: Müller-Stöver
authors.forename: Barbara
authors.initials: B
authors.lastname: Hoppenheit
authors.forename: Dieter
authors.initials: D
authors.lastname: Häussinger
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000818:Animals; D000953:Antigens, Protozoan / Q000032:analysis*; D002648:Child; D002675:Child, Preschool; D002845:Chromatography; D005634:Fructose-Bisphosphate Aldolase / Q000032:analysis*; D006801:Humans; D016778:Malaria, Falciparum / Q000175:diagnosis* / Q000469:parasitology; D008875:Middle Aged; D018512:Parasitemia / Q000175:diagnosis* / Q000469:parasitology; D010963:Plasmodium falciparum / Q000302:isolation & purification; D011506:Proteins / Q000032:analysis*; D011933:Reagent Kits, Diagnostic; D011934:Reagent Strips; D012680:Sensitivity and Specificity; D000099053:Histidine-Rich Glycoprotein
chemical_list: D000953:Antigens, Protozoan; D011506:Proteins; D011933:Reagent Kits, Diagnostic; D011934:Reagent Strips; D000099053:Histidine-Rich Glycoprotein; D005634:Fructose-Bisphosphate Aldolase