Plasmodium knowlesi has been reported as an emerging infection throughout the Southeast Asian region, especially in the Malaysian state of Sabah, where it accounts for the majority of the malaria cases reported. This is in contrast to Europe, where imported P. knowlesi is a rarely reported infection. We present a case of P. knowlesi infection in a Danish woman returning from a short trip to Malaysian Borneo. Microscopy of blood smears revealed 0.8% infected erythrocytes, but due to the atypical morphological presentation, a conclusive species identification was made by molecular methods. Plasmodium knowlesi is a potentially fatal infection and taking the increasing travel activity into consideration after the coronavirus disease 2019 (COVID-19) pandemic, P. knowlesi should be a differential diagnosis in patients with travel-associated illness returning from highly endemic Southeast Asian areas.
Scrub typhus is caused by the mite-borne bacterium Orientia tsutsugamushi. Imported cases have been suspected in Denmark but no diagnostic method has yet been available to confirm the diagnosis. This is a case report of a 38-year-old male admitted to hospital with high fever, severe malaise and headache after returning from Malaysia. Scrub typhus was suspected and the patient recovered after one week of doxycycline treatment. The pathogen was identified by use of microbiome 16S/18S rRNA next-generation sequencing on ethylenediamine tetraacetic acid (EDTA) blood, which in the future may serve an important role in the investigation of travel-associated infections.
We report human infection with simian Plasmodium cynomolgi in a tourist from Denmark who had visited forested areas in peninsular Malaysia and Thailand in August and September 2018. Because P. cynomolgi may go unnoticed by standard malaria diagnostics, this malaria species may be more common in humans than was previously thought.