Thrombocytopenia in Adults with Acute Malaria in Southwestern Nigeria

Thrombocytopenia (<150 x 10 9 /L) has been associated with both Plasmodium falciparum (Pf) and P.vivax (Pv) but there are no studies on platelet count in P. malariae (Pm) malaria which alongside with Pf is endemic in Southwestern Nigeria. In this study, platelet counts were performed on samples from 240 individuals; 60 of whom had Pf , 60 Pm, 60 Pf+Pm malaria and 60 apparently healthy individuals without malaria (controls) in order to determine the effect of these Plasmodium species on platelet count. Malaria parasite test was done by microscopic examination of thick and thin blood films stained with 3% Giemsa. Platelet counts were done using an automated Coulter counter (STKS model). Results showed that 68.3% of the Pf patients, 58.3% of the Pm patients, 66.7% of the Pf+Pm patients and 15.0% of the controls had thrombocytopenia. Thrombocytopenia was not significantly different among the three groups of malarial patients (p=0.47). Compared to the control group, the prevalence of thrombocytopenia was significantly higher in Pf (p<0.001), Pm (p<0.001) and Pf+Pm (p<0.001) groups. Overall, a low platelet count was significantly associated with acute malarial infection (p<0.001, OR 10.4, 95% CI 2.49-43.39). This study shows that thrombocytopenia is common in acute malaria and its prevalence in Pf, Pm and Pf+Pm malaria is comparable.