Bournez et al.
Exposure of wild ungulates to the Usutu and tick-borne encephalitis viruses in France in 2009-2014: Evidence of undetected flavivirus circulation a decade ago.
Viruses 2020, 12, 10; doi:10.3390/v12010010
In order to improve the knowledge on the distribution of various flaviviruses in France, a study has been carried out using serum banking of samples from hunter-harvested wildlife to estimate the exposure level of wild boar and roe in several regions of France from 2009 to 2014. A total of 758 roe deer samples and 1014 wild boar samples were collected across France. Usutu virus antibodies were detected in animals from six departments, located in southwestern and southeastern France. TBE virus/Louping ill virus (LIV) antibodies were detected (by microsphere immunoassays, MIAs, and virus microneutralization tests , MNTs) at three departments located in eastern France (Marne), southeastern France (Hautes-Pyrénée) and northern France (Yvelines). TBE virus/LIV antibodies have been detected annually from 2010 to 2014, but not in juveniles. Not all sera positive in the MIA could be confirmed in the MNT and therefore it cannot be excluded that infection was by flaviviruses other than TBE virus/LIV. Antibodies to TBE virus/LIV have been detected at two eastern departments where no TBE clinical cases have been reported so far, a finding that confirms the wider distribution of TBE virus in the east of France.