Malaria case clinical profiles and Plasmodium falciparum parasite genetic diversity: a cross sectional survey at two sites of different malaria transmission intensities in Rwanda.
BACKGROUND
Malaria remains a public health challenge in sub-Saharan Africa with Plasmodium falciparum being the principal cause of malaria disease morbidity and mortality. Plasmodium falciparum virulence is attributed, in part, to its population-level genetic diversity-a characteristic that has yet to be studied in Rwanda. Characterizing P. falciparum molecular epidemiology in an area is needed for a better understand of malaria transmission and to inform choice of malaria control strategies.


METHODS
In this health-facility based survey, malaria case clinical profiles and parasite densities as well as parasite genetic diversity were compared among P. falciparum-infected patients identified at two sites of different malaria transmission intensities in Rwanda. Data on demographics and clinical features and finger-prick blood samples for microscopy and parasite genotyping were collected(.) Nested PCR was used to genotype msp-2 alleles of FC27 and 3D7.


RESULTS
Patients' variables of age group, sex, fever (both by patient report and by measured tympanic temperatures), parasite density, and bed net use were found differentially distributed between the higher endemic (Ruhuha) and lower endemic (Mubuga) sites. Overall multiplicity of P. falciparum infection (MOI) was 1.73 but with mean MOI found to vary significantly between 2.13 at Ruhuha and 1.29 at Mubuga (p < 0.0001). At Ruhuha, expected heterozygosity (EH) for FC27 and 3D7 alleles were 0.62 and 0.49, respectively, whilst at Mubuga, EH for FC27 and 3D7 were 0.26 and 0.28, respectively.


CONCLUSIONS
In this study, a higher geometrical mean parasite counts, more polyclonal infections, higher MOI, and higher allelic frequency were observed at the higher malaria-endemic (Ruhuha) compared to the lower malaria-endemic (Mubuga) area. These differences in malaria risk and MOI should be considered when choosing setting-specific malaria control strategies, assessing p. falciparum associated parameters such as drug resistance, immunity and impact of used interventions, and in proper interpretation of malaria vaccine studies.
Medical Research Centre Division, Rwanda Biomedical Centre, PO Box 7162, Kigali, Rwanda. fkkateera@yahoo.com.|Division of Internal Medicine, Department of Infectious Diseases, Centre of Tropical Medicine and Travel Medicine, Meibergdreef 9, 1100 DD, Amsterdam, The Netherlands. fkkateera@yahoo.com.
Fredrick
F
Kateera
Molecular Research Laboratory, Infectious Disease Research Collaboration, New Mulago Hospital Complex, PO Box 7051, Kampala, Uganda.|Department of Pathology, School Biomedical Science, College of Health Science, Makerere University, PO Box 7072, Kampala, Uganda.
Sam L
SL
Nsobya
Molecular Research Laboratory, Infectious Disease Research Collaboration, New Mulago Hospital Complex, PO Box 7051, Kampala, Uganda.
Stephen
S
Tukwasibwe
Division of Internal Medicine, Department of Infectious Diseases, Centre of Tropical Medicine and Travel Medicine, Meibergdreef 9, 1100 DD, Amsterdam, The Netherlands.|Royal Tropical Institute/Koninklijk Instituutvoor de Tropen, KIT Biomedical Research, Meibergdreef 39, 1105 AZ, Amsterdam, The Netherlands.
Petra F
PF
Mens
Medical Research Centre Division, Rwanda Biomedical Centre, PO Box 7162, Kigali, Rwanda.
Emmanuel
E
Hakizimana
Division of Internal Medicine, Department of Infectious Diseases, Centre of Tropical Medicine and Travel Medicine, Meibergdreef 9, 1100 DD, Amsterdam, The Netherlands.
Martin P
MP
Grobusch
School of Medicine, College of Medicine and Health Sciences, University of Rwanda, PO Box 3286, Kigali, Rwanda.
Leon
L
Mutesa
Department of Tropical Medicine, School of Public Health and Tropical Medicine, Vector-Borne Infectious Disease Research Centre, Tulane University, 333 S Liberty Street, Mail code 8317, New Orleans, LA, 70112, USA.
Nirbhay
N
Kumar
Division of Internal Medicine, Department of Infectious Diseases, Centre of Tropical Medicine and Travel Medicine, Meibergdreef 9, 1100 DD, Amsterdam, The Netherlands.
Michele
M
van Vugt
D000293:Adolescent; D000328:Adult; D000368:Aged; D000953:Antigens, Protozoan / Q000235:genetics*; D002648:Child; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D005260:Female; D005787:Gene Frequency; D014644:Genetic Variation; D006801:Humans; D007223:Infant; D016778:Malaria, Falciparum / Q000453:epidemiology* / Q000469:parasitology; D008297:Male; D008875:Middle Aged; D010963:Plasmodium falciparum / Q000235:genetics*; D016133:Polymerase Chain Reaction; D015800:Protozoan Proteins / Q000235:genetics*; D012432:Rwanda / Q000453:epidemiology; D017422:Sequence Analysis, DNA; D055815:Young Adult
D000953:Antigens, Protozoan; D015800:Protozoan Proteins; C065974:merozoite surface protein 2, Plasmodium
Malaria; Multiplicity of infection; Parasite density; Plasmodium falciparum; Rwanda