Dual species infection

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Dual species infection Mixed-species malaria infections certainly occur. Their precise frequency will vary according to the case-mix in the area concerned. In endemic areas where multiple malarial species circulate estimates of prevalence may be as high as 30%, but in other areas this is far lower and would often be regarded as forming fewer than 5% of infections. Recogition by morphology requires the presence of parasite forms that have recognisable species-specific features for two separate species. This may sometimes be easy, but can be challenging when one species predominates. Some examples are shown below: A B Image A: two gametocytes in separate red cells. These clearly have different appearances - one has the elongated and curved form typical of P.falciparum, while the second is "round" with visible round cytoplasmic dots and fimbriation of the red cell - appearances of P.ovale.</br< Image B: a large parasite within the red cell is clearly seen and has the chacteristics of a microgametocyte of P.ovale, but note also a small fine early "double dot" ring form of P.falciparum that is within the same erythocyte - an unusual "dual-parasite" erythrocyte!