Clinical evolution of fever, platelet counts and haemoglobin and its relation with malaria. On admission (10/9) haemogobin level was 9.7 mmol/l and platelet count was normal. After a few days of admission axillary temperature increased, peaking on 29/9, when hourly antipyretics were prescribed. Four days later there was an acute drop on haemoglobin levels and platelet counts. The patient received a blood transfusion on 3/10, resulting in increased platelet count and haemoglobin levels. However, they declined again on 5/10. A positive smear for P. vivax was obtained in 4/10.