Short Answer 
The response explains the challenges in comparing artesunate-sensitive (ART-S) and artesunate-resistant (ART-R) strains of Plasmodium falciparum without specific IC50 values, which measure drug effectiveness. Understanding these values is essential for quantifying the increased dosage needed for ART-R strains due to evolving resistance, ultimately impacting treatment efficacy and strategies in malaria therapy.
Step 1: Understanding the Basics of Resistance
The query concerns the comparison between two strains of Plasmodium falciparum: the ART-S (artesunate-sensitive) strain and the ART-R (artesunate-resistant) strain. Resistance refers to the strain’s ability to survive despite treatment with artesunate, a critical drug in malaria therapy. Changes in sensitivity to artesunate between these strains are due to the evolving resistance which impacts how effective the treatment is.
Step 2: Importance of IC50 Values
The IC50 value indicates the concentration of a drug required to inhibit a biological process by 50%. Without specific IC50 values for both the ART-S and ART-R strains, it is impossible to determine how the resistance impacts drug sensitivity. Knowing these values would allow researchers to quantify the increased amount of artesunate needed for the ART-R strain compared to the ART-S strain.
Step 3: Implications of Resistance on Treatment
As resistance develops, the effectiveness of artesunate diminishes, leading to the necessity of higher dosages to achieve therapeutic effects. This phenomenon is generally expressed in terms of a fold increase in IC50 values. Understanding these ratios is crucial for evaluating treatment efficacy and guiding future malaria therapy strategies, especially in the face of rising drug resistance.