Imported malaria in a non-endemic country: sixteen years of cases in a hospital in the South of Madrid, Spain.

Purpose: Malaria keeps on being a serious global health threat, especially in many tropical countries, where it is endemic. Also in non-endemic countries, like Spain, malaria is an issue that requires attention due to the presence of imported cases.

Methods: This is a retrospective study, including all patients diagnosed with malaria at Severo Ochoa University Hospital from 2006 to 2022, being classified according to: (I) their type of stay in an endemic area as visiting friends and relatives (VFR), migrants of recent arrival (MRA), or tourism and business (T&B), and (II) the mode of presentation as microscopic (MM) or submicroscopic (SMM) malaria.

Results: In this study, 132 patients (23.7% of all suspected) were diagnosed with malaria. The PCR was the most sensitive technique (99.2%), followed by antigen detection (78.8%) and microscopy (75%), with Plasmodium falciparum being the predominant species (94.7%). VFR was the largest group infected with malaria (69.7%), mostly symptomatic (98.2%) and presenting MM (90.2%). Instead, MRA patients (25%) presented milder (47.4%) or no symptoms (31.6%) and higher cases of SMM (42.4%). Coinfection with another imported pathogen was present in 19 patients (14.4%), being MRA more frequently coinfected (30.3%) CONCLUSION: This study shows the need for establishing systems for VFRs to attend pre-travel consultations to reduce malaria imported risk. In the case of MRA, screening for imported diseases should be conducted upon their arrival. Finally, we highlight two cases of co-infection with imported viruses, showing that presence of symptoms resembling malaria from another imported pathogen does not exclude malaria.