Novel genotyping tools for investigating transmission dynamics of Plasmodium falciparum.
BACKGROUND
Differentiation between gametocyte-producing Plasmodium falciparum clones depends on both high levels of stage-specific transcripts and high genetic diversity of the selected genotyping marker obtained by a high-resolution typing method. By analyzing consecutive samples of one host, the contribution of each infecting clone to transmission and the dynamics of gametocyte production in multiclone infections can be studied.


METHODS
We have evaluated capillary electrophoresis based differentiation of 6 length-polymorphic gametocyte genes. RNA and DNA of 25 µL whole blood from 46 individuals from Burkina Faso were simultaneously genotyped.


RESULTS
Highest discrimination power was achieved by pfs230 with 18 alleles, followed by pfg377 with 15 alleles. When assays were performed in parallel on RNA and DNA, 85.7% of all pfs230 samples and 59.5% of all pfg377 samples contained at least one matching genotype in DNA and RNA.


CONCLUSIONS
The imperfect detection in both, DNA and RNA, was identified as major limitation for investigating transmission dynamics, owing primarily to the volume of blood processed and the incomplete representation of all clones in the sample tested. Abundant low-density gametocyte carriers impede clone detectability, which may be improved by analyzing larger volumes and detecting initially sequestered gametocyte clones in follow-up samples.
Medical Parasitology and Infection Biology, Swiss Tropical and Public Health Institute University of Basel, Switzerland.
Rahel
R
Wampfler
Medical Parasitology and Infection Biology, Swiss Tropical and Public Health Institute University of Basel, Switzerland Papua New Guinea Institute of Medical Research, Goroka, Eastern Highland Province.
Lincoln
L
Timinao
Medical Parasitology and Infection Biology, Swiss Tropical and Public Health Institute University of Basel, Switzerland.
Hans-Peter
HP
Beck
Centre National de Recherche et de Formation sur le Paludisme, Ouagadougou, Burkina Faso.
Issiaka
I
Soulama
Centre National de Recherche et de Formation sur le Paludisme, Ouagadougou, Burkina Faso.
Alfred B
AB
Tiono
Papua New Guinea Institute of Medical Research, Goroka, Eastern Highland Province.
Peter
P
Siba
Walter and Eliza Hall Institute, Parkville, Victoria, Australia Barcelona Centre for International Health Research (CRESIB), Spain.
Ivo
I
Mueller
Medical Parasitology and Infection Biology, Swiss Tropical and Public Health Institute University of Basel, Switzerland.
Ingrid
I
Felger
D000483:Alleles; D000595:Amino Acid Sequence; D002050:Burkina Faso / Q000453:epidemiology; D016054:DNA, Protozoan / Q000235:genetics; D005838:Genotype; D006801:Humans; D016778:Malaria, Falciparum / Q000453:epidemiology / Q000469:parasitology*; D008969:Molecular Sequence Data; D010963:Plasmodium falciparum / Q000235:genetics*; D016053:RNA, Protozoan / Q000235:genetics
D016054:DNA, Protozoan; D016053:RNA, Protozoan
Plasmodium falciparum; capillary electrophoresis; gametocytes; genotyping; pfg377; pfs230; transmission dynamics