Plasmodium falciparum histidine rich protein (PfHRP2 and 3) diversity in Western and Coastal Kenya.
- Maureen Akinyi, Kenya Medical Research Institute (KEMRI)
Presented at 21st Annual HuQAS Scientific Conference
Plasmodium falciparum histidine-rich proteins 2 (PfHRP2) based RDTs are
advocated in falciparum malaria-endemic regions, particularly when quality
microscopy is not available.
However, diversity and any deletion in the pfhrp2
and pfhrp3 genes can affect the performance of PfHRP2-based RDTs. A total of
400 samples collected from uncomplicated malaria cases from Kenya were
investigated for the amino acid repeat profiles in exon 2 of pfhrp2 and pfhrp3
genes.
In addition, PfHRP2 levels were measured in 96 individuals with
uncomplicated malaria. We observed a unique distribution pattern of amino acid
repeats both in the PfHRP2 and PfHRP3. 228 PfHRP2 and 124 PfHRP3
different amino acid sequences were identified. Of this, 214 (94%) PfHRP2 and
81 (65%) PfHRP3 amino acid sequences occurred only once.
Thirty-nine new
PfHRP2 and 20 new PfHRP3 amino acid repeat types were identified. PfHRP2
levels were not correlated with parasitemia or the number of PfHRP2 repeat
types. This study shows the variability of PfHRP2, PfHRP3 and PfHRP2
concentration among uncomplicated malaria cases. These findings will be
useful to understand the performance of PfHRP2-based RDTs in Kenya.