title: Plasmodium falciparum Merozoite Surface Protein-1 Polymorphisms among Asymptomatic Sickle Cell Anemia Patients in Nigeria.
abstract: Asymptomatic malaria (ASM) has been implicated in the development of hemolytic crisis in infected sickle cell anemia (SCA) patients worldwide. This study surveyed steady state SCA Nigerian patients for ASM to investigate the influence of malaria prevention behaviors and age on parasitaemia and multiplicity of infection (MOI). A total of 78 steady SCA patients aged 5 - 27 years on routine care at three health facilities in Lagos were investigated for ASM by light microscopy and PCR with a multiplicity of infection determined by genotyping block 2 of merozoite surface protein 1 (msp1) gene of Plasmodium falciparum (P. falciparum). Use of malaria prevention measures was captured using a semi-structured questionnaire. The prevalence rates of ASM (due to Pf only) by microscopy and PCR were found to be 27.3% and 47.4% respectively (P < 0.05) with a Mean + SEM parasite density of 2238.4 + 464.3 parasites/uL. Five distinct msp1 genotypes [K1 (2), MAD20 (2), RO33 (1)] were detected and significant (P<0.05) disparity in allele frequencies (K1, 91.8%, MAD20, 32.4%; RO33, 18.9%) was found. The overall MOI was 1.43 and 37.8% of infections were polyclonal (P<0.05). ASM was associated with non-use of preventive measures and occurred in 62.1% of SCA patients aged < 10y with lower MOI of 1.3 compared to 38.1% in older patients with a higher MOI of 1.5 (P<0.05). We conclude that PCR improved the diagnosis of ASM among Nigerian SCA patients with infections being of low complexity and associated with non-use of preventive interventions and R033 msp1 allele selection.
authors: Molecular Biology and Biotechnology Division, Nigerian Institute of Medical Research, Lagos, Nigeria .
authors: Iwalokun
authors: I
authors: Bamidele Abiodun
authors: Department of Medical Microbiology and Parasitoogy, Olabisi Onabanjo University, Sagamu-Ogun State.
authors: Afolabi
authors: A
authors: Oluwadun
authors: Maternal and Child Complex, Isolo General Hospital, Nigeria.
authors: Aina
authors: A
authors: Olugbenga Ayoola
authors: Olorunda Primary Health Centre, Badagry, Lagos, Nigeria.
authors: Iwalokun
authors: I
authors: Senapon Olusola
mesh_terms: D000293:Adolescent; D000328:Adult; D000483:Alleles; D000755:Anemia, Sickle Cell / Q000469:parasitology*; D002648:Child; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D005260:Female; D005787:Gene Frequency; D005838:Genotype; D006801:Humans; D016778:Malaria, Falciparum / Q000469:parasitology*; D008297:Male; D020066:Merozoite Surface Protein 1 / Q000235:genetics*; D009549:Nigeria; D010963:Plasmodium falciparum / Q000235:genetics* / Q000302:isolation & purification; D016133:Polymerase Chain Reaction; D011110:Polymorphism, Genetic; D015995:Prevalence; D055815:Young Adult
chemical_list: D020066:Merozoite Surface Protein 1
keywords: Asymptomatic malaria; Chemoprophylaxis; Multiplicity of infection; Parasite diversity; Plasmodium falciparum