Direct detection and quantification of liver-stage Plasmodium parasites became possible with the development of quantitative real-time PCR (qPCR). Here we describe the measurement of parasite burden in the livers of mice infected with the rodent malaria species, Plasmodium berghei and Plasmodium yoelii. This method is based on detection of expression of parasite ribosomal 18S RNA and can serve as an endpoint to accurately evaluate the efficacy of vaccines targeting the preerythrocytic stages of malaria. This approach is fast and highly reproducible and allows quantification of liver-stage parasite burden in different mouse strains and different Plasmodium species after infection with a range of sporozoite challenge doses.
Keywords: 18S ribosomal RNA; Liver-stage; Malaria; Parasite load; Plasmodium; Real-time PCR.