Ex Vivo Drug Sensitivity Profiles of Plasmodium falciparum Field Isolates from Cambodia and Thailand, 2005 to 2010, Determined by a Histidine-Rich Protein-2 Assay
Abstract
HRP-2 assay, when field deployed proximal to P. falciparum collection sites, allows for immediate ex vivo (IEV) field isolate processing. IEV, by avoiding cryopreservation and culture-adaptation before IC50 determination, may reduce clonal selection, better preserving parasite subpopulations with variable drug susceptibility profiles, the latter likely present in a smaller proportion than wild-type drug susceptible parasites. Here, to characterize recent geographical and temporal trends in western and northern Cambodia, and eastern Thailand, including years when reduced artemisinin susceptibility was first described, an HRP-2 assay, with IEV field isolate processing was used to determine IC50 values of P. falciparum field isolates obtained from 2005 to 2010. Among P. falciparum field isolates obtained in western Cambodia from 2005 to 2010, steady increases were observed for GM IC50 values measured by a HRP-2 in vitro assay against a range of anti-malarial drugs, including AS and DHA. Moreover, in northern Cambodia, assessed in 2009 and 2010, most GM IC50 values approximated those in western Cambodia, during the same period. This supports the notion that western Cambodia is associated with sustained and likely progressive reductions in anti-malarial drug susceptibility, with possible spread to northern Cambodia. Increases in GM IC50 values for a range of important anti-malarial drugs in a region of emerging drug resistance underscores the importance of harmonizing methodologies that allow for accurate comparison between geographical locations, and over time, so that potentially important trends in drug susceptibility can be identified.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 13, 2012
- Accession Number
- ADA619179
Entities
People
- Chanthap Lon
- Darapiseth Sea
- Delia Bethell
- Doung Socheat
- Harald Noedl
- Kurt Schaecher
- Stuart D. Tyner
- Wichai Satimai
- Wiriya Rutvisuttinunt
- Youry Se
Organizations
- Armed Forces Research Institute of Medical Sciences