St. Abb’s Head phlebovirus – a separate virus species or a strain of Uukuniemi phlebovirus?

Abstract

St. Abb’s Head virus (SAHV), a member of the genus Phlebovirus (family Phenuiviridae, order Bunyavirales), belongs to the largest group of negative strand RNA viruses. All phleboviruses share a genome structure that comprises three segments of negative-sense or ambi-sense RNA. The viral genome is composed of the small (S), medium (M) and large (L) RNA segments. The S segment encodes the nucleocapsid (N) protein, the M segment encodes the precursor for the viral glycoproteins (Gn and Gc) and the L segment encodes the viral RNA-dependent RNA polymerase (RdRp). Some viruses within the genus also encode non-structural proteins within their S or M segments. SAHV was isolated from a pool of seabird ticks (Ixodes uriae) collected at a seabird colony in St. Abb’s Head National Nature Reserve, Berwickshire, Scotland in 1979. Antigenically, SAHV appeared to be related to the Uukuniemi serogroup of phleboviruses. Similarly, the proteins of SAHV shared similar biochemical properties to Uukuniemi phlebovirus. Here, we describe an in depth molecular characterisation of SAHV. Using next generation sequencing technology, we demonstrate that SAHV is very closely related to the Uukuniemi phlebovirus (UUKV). We examine the growth of SAHV in mammalian, avian and tick celllines and define its target cell tropism.