Characterization of the Uukuniemi Virus Group (Phlebovirus: Bunyaviridae): Evidence for Seven Distinct Species

Evolutionary insights into the phleboviruses are limited because of an imprecise classification scheme based on partial nucleo-tide sequences and scattered antigenic relationships. In this report, the serologic and phylogenetic relationships of the Uukuni-emi group viruses and their relationships with other recently characterized tick-borne phleboviruses are described using full-length genome sequences. We propose that the viruses currently included in theUukuniemi virus group be assigned to five different species as follows: Uukuniemi virus, EgAn 1825-61 virus, Fin V707 virus, Chizé virus, and Zaliv Terpenia virus would be classified into the Uukuniemi species;Murre virus, RML-105-105355 virus, and Sunday Canyon virus would be classified into aMurre virus species; and Grand Arbaud virus, Precarious Point virus, andManawa virus would each be given individual spe-cies status. Although limited sequence similarity was detected between current members of theUukuniemi group and Severe fever with thrombocytopenia syndrome virus (SFTSV) and Heartland virus, a clear serological reaction was observed between some of them, indicating that SFTSV andHeartland virus should be considered part of the Uukuniemi virus group. Moreover, based on the genomic diversity of the phleboviruses and given the low correlation observed between complement fixation titers and genetic distance, we propose a system for classification of the Bunyaviridae based on genetic as well as serological data. Fi-nally, the recent descriptions of SFTSV and Heartland virus also indicate that the public health importance of the Uukuniemi group viruses must be reevaluated