Globally, rapid diagnostic tests (RDTs) are critical for monitoring and maintaining health by allowing rapid identification of malaria cases in areas without microscopy facilities. Many standard malaria RDTs detect the antigen PfHRP2\text{PfHRP2}PfHRP2 (histidine-rich protein 2).
Which statement correctly identifies a limitation or mechanism of using PfHRP2\text{PfHRP2}PfHRP2-based RDTs for malaria monitoring and diagnosis?
PfHRP2\text{PfHRP2}PfHRP2 is a host-derived antibody that persists in the bloodstream for years, making it impossible to distinguish between active and past infections.
Some P. falciparum\textit{P. falciparum}P. falciparum populations have evolved deletions of the pfhrp2\textit{pfhrp2}pfhrp2 gene, leading to false-negative RDT results that threaten global surveillance efforts.
PfHRP2\text{PfHRP2}PfHRP2 is rapidly degraded within minutes of parasite death, allowing healthcare workers to use these RDTs to monitor real-time clearance of parasites during treatment.
The PfHRP2\text{PfHRP2}PfHRP2 antigen is unique to the dormant hypnozoite liver stage of Plasmodium vivax\textit{Plasmodium vivax}Plasmodium vivax, meaning it cannot detect active erythrocytic infections.
97 exam-style questions on OCR GCSE Biology 6.3 Monitoring and maintaining health, covering 6.3.1 Health and disease, 6.3.2 Interactions between diseases, 6.3.3 Spread of communicable diseases, 6.3.4 Common infections and diseases, 6.3.5 Physical plant defence responses, 6.3.6 Chemical plant defence responses, 6.3.7 Detecting and identifying plant diseases, 6.3.8 White blood cells and platelets, 6.3.9 Non-specific defence systems, 6.3.10 The immune system, 6.3.11 Monoclonal antibodies, 6.3.12 Vaccines and medicines, 6.3.13 Aseptic techniques, 6.3.14 Discovery and development of new medicines, 6.3.15 Causes of non-communicable diseases, 6.3.16 Treatments for cardiovascular disease, 6.3.17 Lifestyle factors and non-communicable diseases, 6.3.18 Cancer, 6.3.19 Stem cells in medicine, 6.3.20 Gene technology in medicine, and 6.3.21 The human genome and medicine. Each one has a worked solution and a mark scheme showing where the marks go.