How prevalant are Plasmodium ovale and P-malariae in East Asia?

Plasmodium ovale and Plasmodium malariae, two of the four human malaria par asites, are usually found at very low prevalence in East Asia, even in area s with intense malaria transmission. In this article, Fumihiko Kawamoto, Qi ng Liu, Marcelo Ferreira and Indah Tantular review data obtained in recent field surveys, using alternative diagnostic methods such as acridine orange staining and PCR-based methods, to evaluate the prevalence of these two ma laria species in East Asia. They argue that these species might be much mor e prevalent in East Asia than reported previously. In addition, they discus s the implications of sequence variations found in the small subunit riboso mal RNA genes of the two species targeted by diagnostic PCR and compare mor phological criteria for speciation Of malaria parasites stained with Giemsa and acridine orange.