Platelet Abnormalities in Malaria.

Previous studies have demonstrated a significant and consistent enlargement of human platelets during acute malaria attacks. In a prospective study platelet morphology and function were studied in 20 male patients with acute Plasmodium vivax or P. falciparum infections. These studies included bleeding time, platelet aggregation, platelet counts and electron micorscopy. The tests were performed during the malaria attack and after successful therapy. More than 50 of the patients had less than 150,000 plateletscu mm during the acute attack of these the majority had normal numbers when they left the hospital. Bleeding time became shorter after therapy, but the initial value was generally less than 10 min. Platelet aggregation was performed only in four patients Adenosine diphosphate-induced aggregation was low in each case and improved significantly after therapy. Electron microscopy in nine of the patients revealed platelet inclusions suggestive of degenerating parasitic material. Aspirin was ruled out as the cause of these lesions by examining the platelets of volunteers before and after the ingestion of 2 gm of acetylsalicylic acid. Modified author abstract