Adding Virome Capture Metagenomic Sequencing to Conventional Laboratory Testing Increases Unknown Fever Etiology Determination in Bamako, Mali.

Unexplained fever poses significant diagnostic challenges in resource-limited settings like Bamako, Mali, where overlapping endemic diseases include malaria, HIV/AIDS, yellow fever, typhoid, and others. This study aimed to elucidate the infectious etiologies of acute febrile illnesses in this context. Acute febrile patients of any age were enrolled after informed consent or assent. Baseline clinical and demographic data were collected, and samples were analyzed by using rapid diagnostic tests, reverse transcriptase polymerase chain reaction, ELISA, and virus-targeted metagenomic sequencing (virome capture sequencing platform for vertebrate viruses [VirCapSeq-VERT]). Among 108 enrolled subjects, most were male (51.9%) and under 15 years old (56.5%). Measles virus was identified in 39.8% of cases, primarily among children. Other findings included Plasmodium spp. (12%), Salmonella spp. (13%), and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2; 8.7%). The virome capture sequencing platform for vertebrate viruses was used for 101 subjects, corroborating many routine test results and identifying additional cases of measles virus (1), SARS-CoV-2 (5), and numerous other agents. Notably, nearly all subjects showed evidence of herpesviruses (90%) and anelloviruses (98%). Hemorrhagic fever viruses were not observed. With the inclusion of VirCapSeq-VERT, identifiable pathogens were found in 79.6% of cases, leaving 20.4% without a clear etiology. The identification of more than one concurrent pathogen was common (41.5%). Integrating metagenomic sequencing with routine laboratory diagnostic testing enhances the detection of pathogens in acute febrile illnesses, highlighting its potential value in identifying infectious etiologies in resource-limited settings.