[DNA amplification of Plasmodium vivax parasites from Giemsa-stained blood smears].

OBJECTIVE: To develop methods of extracting DNA from malaria parasites on Giemsa-stained blood smears. METHODS: Improved Na2HPO4 method and Chelex-100 ion-exchange technique were used to extract DNA from Giemsa-stained or unstained blood smears. Nested PCR was employed for amplification and identification of allelotype in the Plasmodium vivax merozoite surface protein-1 (PvMSP-1). RESULTS: Target DNA bands appeared in all samples of unstained thick blood smears, while no DNA bands were visible in the fixed and stained thin smears. Both methods identified PvMSP-1 alleles from smears with parasitemia of > or = 0.01%. CONCLUSION: It is feasible to identify PvMSP-1 alleles from Giemsa-stained blood smear.