Abstract: The blood sample from a case of vivax malaria in Tengchong City, Yunnan Province, was tested with CareStartTM malaria rapid diagnostic test, Giemsa staining and nested PCR in 2012. The case was determined to be infected with Plasmodium vivax, P. malariae or P. ovale other than P. falciparum by CareStartTM malaria rapid diagnostic test. Microscopic results revealed multinuclear P. vivax ring form and multi-infections with P. vivax in blood slides, with occurrence of two or more nuclei in one ring form accounting for 14.68%（188/1 280）, and parasitism of two or more P. vivax rings in one erythrocyte accounting for 22.50%（288/1 280）. In addition, co-occurrence of ring form and trophozoite, and ring form and gametophyte was found in erythrocytes. Nested PCR revealed P. vivax-specific amplification products. Combining the results with epidemiological information and clinical symptoms, this case was finally diagnosed as imported vivax malaria, and the erythrocytes of the case harbored different stages of P. vivax parasites.

Key words: Plasmodium vivax, Ring stage, Multinuclear, Multi-infection