Abstract:

Objective  To identify and analyze Plasmodium ovale wallikeri in 5 imported malaria cases， who were detected positive by microscopy and negative by conventional PCR.  Methods  Epidemiological information and blood samples were collected from the five patients. The detection was conducted by microscopy， Rapid Diagnostic Test（RDT） and nested PCR with Plasmodium genus-specific， species-specific and Plasmodium ovale wallikeri-specific primers. The amplified products were sequenced and Blast analysis was performed on line in NCBI.  Results  The five patients returned from Africa， and all had a history of malaria. They were microscopically positive for Plasmodium sp.， and two cases showed Pan positive RDT result. All blood samples were negative for four Plasmodium spp. by conventional nested PCR， but positive by nested PCR with Plasmodium ovale wallikeri-specific primers. Blast analysis showed that the amplified sequences of the five cases had complete homology with P. ovale wallikeri clone RSH10 18S ribosomal RNA gene （Accession No. KF219561.1）.  Conclusion  The five cases which classified as positive by microscopy while negative by conventional PCR have been confirmed as Plasmodium ovale wallikeri infection by nested PCR with P. ovale wallikeri-specific primers.

Key words: Malaria, Plasmodium ovale, Nested PCR