Complete coding sequence of the Alkhurma virus, a tick-borne flavivirus causing severe hemorrhagic fever in humans in Saudi Arabia

To date, tick-borne flaviviruses responsible for hemorrhagic fever in human s have been isolated in Siberia (Omsk hemorrhagic fever virus), India (Kyas anur Forest disease virus, KFDV), and in Saudi Arabia (Alkhurma virus, ALKV ). Prior to this study, only partial coding sequences of these severe patho gens had been determined. We report here the complete coding sequence of AL K virus, which was determined to be 10,248 nucleotides (nt) long, and to en code a single 3,416 amino acid polyprotein. Independent analyses of the com plete polyprotein and the envelope protein provided genetic and phylogeneti c evidence that ALKV belongs to the tick-borne flavivirus group, within whi ch it is most closely related to KFDV. Analysis of structural genes, geneti c distances, and evolutionary relationship indicate that ALKV and KFDV deri ved from a common phylogenetic ancestor and constitute two genetic subtypes of the same virus species according to current genetic criteria of classif ication. (C) 2001 Academic Press.