Nosocomial malaria transmissions resolved by genomic analyses - a retrospective case report study in France (2007-2021)

Publié le 8 octobre 2022
Mis à jour le 31 octobre 2022

BACKGROUND: Exposure of blood to malaria parasites can lead to infection even in the absence of the anopheles mosquito vector. During a stay in a healthcare facility, accidental inoculation of the skin with blood from a malaria patient might occur, referred to as nosocomial malaria transmission. METHODS: Between 2007 and 2021, we identified six autochthonous malaria cases that occurred in six different French hospitals, originating from nosocomial transmission and imported malaria patients being the infection source. Four cases were observed during the COVID-19 pandemic. The genetic relatedness between source and nosocomial infections was evaluated by genome-wide short tandem repeats (STRs) and single-nucleotide polymorphisms (SNPs). RESULTS: None of the patients with autochthonous malaria had travel history to an endemic area nor had been transfused. For each case, both the source and recipient patients stayed a few hours in the same ward. After diagnosis, autochthonous cases were treated with antimalarials and all recovered except one. Genetically, each pair of matched source/nosocomial parasite infections showed less than 1% of different genome-wide STRs, and less than 6.9% (<1.5% for monoclonal infections) of different SNPs. Similar levels of genetic differences were obtained for parasite DNA samples that were independently sequenced twice as references of identical infections. Parasite phylogenomic results were consistent with travel information reported by the source patients. CONCLUSIONS: Our study demonstrates that genomics analyses may resolve nosocomial malaria transmissions, despite the uncertainty regarding the modes of contamination. Nosocomial transmission of potentially life-threatening parasites should be taken into consideration in settings or occasions where compliance with universal precautions is not rigorous.

Auteur : Coppée Romain, Sarrasin Véronique, Zaffaroulah Rizwana, Bouzayene Azza, Thellier Marc, Noël Harold, Clain Jérôme, Houzé Sandrine
Clinical infectious diseases : an official publication of the Infectious Diseases Society of America, 2022