A thin blood smear from a patient suspected of having malaria reveals numerous normal size erythrocytes without stippling but with ring stages, many with multiple ring stages and applique forms. Several erythrocytes show developing trophozoites that are spread across the erythrocytes in a band fashion. Which of the following is the most likely cause of infection?
Multiple ring stages and applique forms are indicative of P. falciparum Several erythrocytes show developing trophozoites that are spread across the erythrocytes in a band fashion that is indicative of P. malariae infection. Normal size erythrocytes without stippling (Schuffner dots) would exclude P. vivax and P. ovale. Morphologic differences are the primary means of diagnosis. In this scenario, more than one species forms are identified in the blood smear, indicating a meixed infection. Ref: Ray C.G., Ryan K.J. (2010). Chapter 50. Sporozoa. In C.G. Ray, K.J. Ryan (Eds), Sherris Medical Microbiology, 5e.
Plasmodium vivax
Plasmodium malariae
Plasmodium ovale
A mixed infection with two Plasmodium species