in vitro module
The drug susceptibility of the Plasmodium falciparum parasite can be assessed with in vitro testing to measure fundamental parasite antimalarial sensitivity. Determining growth of a parasite apart from the human host eliminates host effects such as drug metabolism and immunity. The in vitro module of the WWARN database will contain the results of such tests from parasites collected from infected patients around the world.
In addition to coordinating a database of test results and methods to understand and compare them, WWARN will support the use of common protocols, shared test reagents, and agreed standard strains of Plasmodium to use as controls. Encouraging common key parameters of in vitro tests and associated measures of quality control, for example the use of standard reference clones, will allow comparison of in vitro susceptibilities between laboratories and within a single laboratory over time. The results will contribute to the understanding of parasite resistance and its geographic and temporal patterns. WWARN will offer standard drugs, standard operating procedures and technical training as requested by laboratories that wish to establish similar practices.
More information is available by emailing invitro@wwarn.org
in vitro Tools
http://www.antimalarial-icestimator.net
ICEstimator version 1.2 allows simple management of data measuring the effect of clones, strains, or isolates of malaria parasites resulting from uptake of labelled nutrient (isotopic test), production of proteins (ELISA tests), or growth (schizont maturation). The software estimates drug concentration that inhibits growth by 50% (IC50) using the nls function of R, which is freely available here: http://www.r-project.org/
HN-NonLin is a basic, free tool developed to facilitate the analysis of malaria in vitro drug sensitivity test results. This software allows for the entry of raw data obtained from drug sensitivity assays (such as isotopic assays, colorimetric assays, or schizont maturation tests), calculates the principal parameters of drug sensitivity (inhibitory concentrations), and plots the dose-response curves for individual isolates, strains or clones.
Many thanks to colleague Harald Noedl for this software.
In vitro testing protocols published by WHO are available here.
Resources
in vitro testing, Bobo Dioulasso, Burkina Faso
Each evening after a daily collection of pre-treatment samples from malaria-infected patients, parasitized RBCs are cultivated in low oxygen condition with ascending concentrations of drugs to confirm biological resistance. Photo courtesy Jean Bosco Ouedraogo, 1984.
