Diagnostic Difficulties with Plasmodium knowlesi Infection in Humans

Abstract

Studies conducted in Malaysia have raised questions about Plasmodium knowlesi as the fifth human pathogenic malaria parasite (1,2); additional cases of P. knowlesi malaria have subsequently been reported from other Asian countries (3–5). Microscopic diagnosis is hindered because P. knowlesi morphologically resembles P. falciparum or P. malariae, depending on blood stage (6). Singh et al. has designed a nested PCR assay for identifi cation of P. knowlesi infections (1).