Diagnosis and therapy for hospitalized imported malaria in adults in Italy

BACKGROUND: The diagnosis and treatment of malaria in non-endemic countries presents a continuing challenge.

METHODS: Medical records were reviewed for 291 patients hospitalized with microscopically confirmed malaria diagnosed consecutively in two infectious diseases wards in Milano, Italy, between 1998 and 2007.

RESULTS: One hundred eighty-six (64%) were male; median age was 35 y (range 16-72 y). Of the 291 patients, 204 (70.1%) were non-immune travelers and 87 (29.9%) were considered semi-immune. In 228 patients (78.3%), Plasmodium falciparum was identified as the only causative malarial parasite. In 48 (16.5%), 9 (3.1%), and 1 (0.3%) cases, Plasmodium vivax, Plasmodium ovale, and Plasmodium malariae were diagnosed, respectively. Five mixed infections were observed (1.7%). Of the 233 falciparum cases (including mixed infections), 222 (95.3%) were acquired in sub-Saharan Africa. Fifty-four percent of P vivax infection were acquired in the Indian subcontinent and Southeast Asia. Chemoprophylaxis was used by 23.6% (61/258) subjects with only 32 fully compliant with the recommended regimen. At admission, fever, chills, and headache were present in 95.5, 59.5, and 55.3% of cases, respectively. Elevated serum lactate dehydrogenase levels (95%) and thrombocytopenia (82%) were the most frequently detected laboratory abnormalities. Thirty-five patients (15%) with P falciparum malaria presented with severe malaria according to the WHO criteria; in 19 patients (54.3%) more than one criteria was present. All patients recovered uneventfully. Inappropriate anti-malarial treatment occurred in 25 patients (8.6%) and were recorded more frequently among patients with a diagnosis of P vivax malaria (29.1%) as opposed to those affected by P falciparum (3.9%).

CONCLUSIONS: In our study more than two thirds of imported malaria cases were due to P falciparum with an excess of cases diagnosed in immigrants starting from the year 2000. Despite many available guidelines inappropriate initial malaria treatment is relatively frequent even when patients are managed in an infectious diseases ward.