To describe nosocomial transmission of malaria from patient to patient via blood exposure.

A 56-year-old man was admitted to an Italian hospital with fever and Plasmodium falciparum parasitemia, but with no risk factors for malaria. Twenty days earlier, he had been admitted for bronchopulmonary disease to the hospital's intensive care unit, where a woman with P. falciparum malaria acquired abroad was present.

We reviewed both patients' medical records and searched for mosquitoes in the hospital and on the grounds. We interviewed the staff about patient care practices potentially involving contact with blood. The genetic identities of strains were determined by genotyping of the DNA extracted from blood.

Molecular genotyping showed that the two strains were identical. The only invasive procedures performed on both patients by the same staff on the same shift were capillary blood sampling by finger stick, intravenous drug administration, and substitution of total parenteral nutrition bags and intravenous sets. The flngerstick device used was designed to prevent person-to-person transmission of blood-borne infections, and the staff interviews did not reveal any incorrect use of aseptic techniques. The likely source of infection was identified during a training course 6 months later: a nurse reported that, when collecting blood, she placed patients' fingers directly on the blood glucose meter, a practice she had learned from a poster advertising the device.

A nosocomial case of malaria was ascertained, which was likely due to patient-to-patient transmission via a contaminated blood glucose meter. Incomplete instructions for the meter seem to have played a role in this case.