Can malaria rapid diagnostic tests be used to detect simian malaria?

Area of Science:

• Tropical Medicine
• Parasitology
• Diagnostic Development

Background:

• Zoonotic malaria from non-human primates (NHP) presents diagnostic challenges.
• Human malaria rapid diagnostic tests (RDTs) have not been evaluated for simian malaria.
• Accurate diagnostics are crucial for understanding and controlling NHP malaria transmission.

Purpose of the Study:

• To evaluate the performance of commercially available human malaria RDTs in detecting Plasmodium species in non-human primates.
• To assess the impact of parasite density on RDT sensitivity for simian malaria.
• To compare the efficacy of RDTs detecting different Plasmodium antigens (PfHRP2, pLDH, aldolase).

Main Methods:

• Analyzed 131 NHP blood samples with confirmed malaria using 14 different RDT brands.
• Included 30 malaria-negative macaque samples as controls.
• Utilized quantitative PCR (qPCR) as the reference standard for parasite detection and quantification.

Main Results:

• RDT sensitivity varied from 34.2% to 94.3% across brands and Plasmodium species (P. cynomolgi, P. inui, P. coatneyi).
• Sensitivity exceeded 90% for best-performing RDTs when parasite densities were >200 parasites/μL.
• PfHRP2-positive results occurred in 1-17% of malaria-infected NHP samples; no false positives in controls.

Conclusions:

• RDT performance for simian malaria is influenced by RDT brand, Plasmodium species, and parasite density.
• Most RDT brands demonstrate good sensitivity for simian Plasmodium detection at parasite densities above 200 parasites/μL.
• Further research is needed to optimize RDTs for zoonotic malaria surveillance.