ANALYSIS OF MALARIA PARASITE RNA FROM DECADE-OLD GIEMSA-STAINED BLOODSMEARS AND DRIED MOSQUITOS

We have analyzed RNA isolated from recently prepared and historically preserved slides containing smears of Plasmodium-infected blood. We fo und that slides preserved as long as 20 years can yield RNA that is a suitable template for polymerase chain reaction (PCR) amplification. M osquitoes that have been stored for years under ambient temperature ca n also be used as an RNA source. The RNA amplification from slide-deri ved material is shown to be dependent upon the addition of reverse tra nscriptase and the resultant products are specific to the developmenta l state of the parasite. Amplification of ribosomal RNA with primers c onserved for Plasmodium and hybridization with species-specific probes provide a general, unbiased method for species determination. Messeng er RNA transcripts from slides also appear to serve as templates. The procedure may add complementary information to that derived from micro scopic examination of Giemsa-stained blood smears including species id entification, variant antigen identification and drug resistance statu s.