title: High rate of mixed and subpatent malarial infections in southwest Nigeria.
abstract: The rate of malarial parasitemia in children and adults was assessed by microscopy and the polymerase chain reaction in a holoendemic area in Nigeria. A high rate of subpatent Plasmodium falciparum parasitemia (19.6%) was found. Plasmodium malariae and P. ovale infections were common in a rural area (26.1% and 14.8%) but were observed sporadically in individuals from an urban area. Simultaneous infections with P. falciparum, P. malariae, and P. ovale were frequent in the rural area (11.7% triple infections). The rate of triple infections was higher than expected from the prevalences of each species (P < 0.00001). Spleen enlargement was associated with mixed infections of P. falciparum and P. malariae (odds ratio [OR] = 5.9, 95% confidence interval [CI] 3.0-11.7) and less frequently observed in individuals without detectable parasitemia (OR = 0.06, 95% CI = 0.01-0.3). Spleen enlargement and titers of antibodies to schizonts were positively correlated with parasite densities. The results also suggest that in some individuals a long-lasting subpatent parasitemia might occur.
authors.affiliation: Institut für Tropenmedizin, Medizinische Fakultät Charité der Humboldt-Universität zu Berlin, Germany.
authors.forename: J
authors.initials: J
authors.lastname: May
authors.forename: F P
authors.initials: FP
authors.lastname: Mockenhaupt
authors.forename: O G
authors.initials: OG
authors.lastname: Ademowo
authors.forename: A G
authors.initials: AG
authors.lastname: Falusi
authors.forename: P E
authors.initials: PE
authors.lastname: Olumese
authors.forename: U
authors.initials: U
authors.lastname: Bienzle
authors.forename: C G
authors.initials: CG
authors.lastname: Meyer
mesh_terms: D000293:Adolescent; D000328:Adult; D000818:Animals; D000913:Antibodies, Protozoan / Q000302:isolation & purification; D000953:Antigens, Protozoan / Q000302:isolation & purification; D002648:Child; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007223:Infant; D008288:Malaria / Q000453:epidemiology* / Q000469:parasitology; D016778:Malaria, Falciparum / Q000453:epidemiology*; D008297:Male; D008875:Middle Aged; D009549:Nigeria / Q000453:epidemiology; D010961:Plasmodium / Q000276:immunology / Q000302:isolation & purification; D010963:Plasmodium falciparum / Q000276:immunology / Q000302:isolation & purification; D010965:Plasmodium malariae / Q000276:immunology / Q000302:isolation & purification; D015995:Prevalence; D012423:Rural Health; D013154:Spleen / Q000469:parasitology; D014504:Urban Health
chemical_list: D000913:Antibodies, Protozoan; D000953:Antigens, Protozoan