A novel live-dead staining methodology to study malaria parasite viability

Background: Malaria is a major health and socio-economical problem in tropical and sub-tropical areas of the world. Several methodologies have been used to assess parasite viability during the adaption of field strains to culture or the assessment of drug potential, but these are in general not able to provide an accurate real-time assessment of whether parasites are alive or dead. Methods: Different commercial dyes and kits were assessed for their potential to allow for the real-time detection of whether a blood stage malaria parasite is dead or alive. Results: Here, a methodology is presented based on the potential-sensitive mitochondrial probe JC-1, which allows for the real-time visualization of live (red staining) and/or dead (absence of red staining) blood stage parasites in vitro and ex vivo. This method is applicable across malaria parasite species and strains and allows to visualize all parasite blood stages including gametocytes. Further, this methodology has been assessed also for use in drug sensitivity testing. Conclusions: The JC-1 staining approach is a versatile methodology that can be used to assess parasite viability during the adaptation of field samples to culture and during drug treatment. It was found to hold promise in the assessment of drugs expected to lead to delayed death phenotypes and it currently being evaluated as a method for the assessment of parasite viability during the adaptation of patient-derived Plasmodium vivax to long-term in vitro culture.