Arboviruses and Hemorrhagic Fever Viruses Unit, Virology Department, Institut Pasteur de Dakar, BP220 Dakar, Senegal
Marie Henriette Dior Ndione
Arboviruses and Hemorrhagic Fever Viruses Unit, Virology Department, Institut Pasteur de Dakar, BP220 Dakar, Senegal
Nicholas Di Paola
Laboratory of Molecular Evolution and Bioinformatics, Department of Microbiology, Biomedical Sciences Institute, University of Sao Paulo, Sao Paulo 05508-000, SP, Brazil
Gamou Fall
Arboviruses and Hemorrhagic Fever Viruses Unit, Virology Department, Institut Pasteur de Dakar, BP220 Dakar, Senegal
André Pouwedeou Bedekelabou
Ecole Inter-Etats des Sciences et Médecine Vétérinaires de Dakar, BP5077 Dakar, Senegal
Pape Mbacké Sembène
Department of Animal Biology, Faculty of Science et Technics, Université Cheikh Anta Diop de Dakar (UCAD), BP 5005 Fann, Dakar, Senegal
Ousmane Faye
Arboviruses and Hemorrhagic Fever Viruses Unit, Virology Department, Institut Pasteur de Dakar, BP220 Dakar, Senegal
Paolo Marinho de Andrade Zanotto
Laboratory of Molecular Evolution and Bioinformatics, Department of Microbiology, Biomedical Sciences Institute, University of Sao Paulo, Sao Paulo 05508-000, SP, Brazil
Amadou Alpha Sall
Arboviruses and Hemorrhagic Fever Viruses Unit, Virology Department, Institut Pasteur de Dakar, BP220 Dakar, Senegal
Usutu virus (USUV) is a Culex-associated mosquito-borne flavivirus of the Flaviviridae family. Since its discovery in 1959, the virus has been isolated from birds, arthropods and humans in Europe and Africa. An increasing number of Usutu virus infections in humans with neurological presentations have been reported. Recently, the virus has been detected in bats and horses, which deviates from the currently proposed enzootic cycle of USUV involving several different avian and mosquito species. Despite this increasing number of viral detections in different mammalian hosts, the existence of a non-avian reservoir remains unresolved. In Kedougou, a tropical region in the southeast corner of Senegal, Usutu virus was detected, isolated and sequenced from five asymptomatic small mammals: Two different rodent species and a single species of shrew. Additional molecular characterization and in vivo growth dynamics showed that these rodents/shrew-derived viruses are closely related to the reference strain (accession number: AF013412) and are as pathogenic as other characterized strains associated with neurological invasions in human. This is the first evidence of Usutu virus isolation from rodents or shrews. Our findings emphasize the need to consider a closer monitoring of terrestrial small mammals in future active surveillance, public health, and epidemiological efforts in response to USUV in both Africa and Europe.
