Usutu Virus Isolated from Rodents in Senegal

Area of Science:

• Virology
• Ecology
• Epidemiology

Background:

• Usutu virus (USUV) is a mosquito-borne flavivirus primarily associated with birds.
• Recent detections in bats and horses suggest a broader host range, challenging the established enzootic cycle.
• The potential for non-avian reservoirs of USUV remains largely unexplored.

Purpose of the Study:

• To investigate the presence of Usutu virus in small mammals in Senegal.
• To characterize novel USUV isolates from these mammals.
• To assess the potential role of small mammals as USUV reservoirs.

Main Methods:

• Detection, isolation, and sequencing of Usutu virus from small mammals in Kedougou, Senegal.
• Molecular characterization of viral isolates.
• In vivo growth dynamics and pathogenicity assessment.

Main Results:

• Usutu virus was successfully isolated from five asymptomatic small mammals (rodents and a shrew).
• These isolates were genetically similar to known pathogenic USUV strains.
• This marks the first isolation of Usutu virus from rodents or shrews.

Conclusions:

• Terrestrial small mammals, specifically rodents and shrews, can harbor Usutu virus.
• These findings necessitate enhanced surveillance of small mammals for USUV in Africa and Europe.
• Considering small mammals in epidemiological efforts is crucial for understanding and controlling USUV transmission.