Phylogenetic and Timescale Analysis of Barmah Forest Virus as Inferred from Genome Sequence Analysis.

Alice Michie,Andrew Jardine,Allison Imrie,Timo Ernst,David W Smith,John S Mackenzie,Michael D A Lindsay,Peter J Neville,I-Ly Joanna Chua,Jay Nicholson

doi:10.3390/v12070732

Abstract

Barmah Forest virus (BFV) is a medically important mosquito-borne alphavirus endemic to Australia. Symptomatic disease can be a major cause of morbidity, associated with fever, rash, and debilitating arthralgia. BFV disease is similar to that caused by Ross River virus (RRV), the other major Australian alphavirus. Currently, just four BFV whole-genome sequences are available with no genome-scale phylogeny in existence to robustly characterise genetic diversity. Thirty novel genome sequences were derived for this study, for a final 34-taxon dataset sampled over a 44 year period. Three distinct BFV genotypes were characterised (G1–3) that have circulated in Australia and Papua New Guinea (PNG). Evidence of spatio-temporal co-circulation of G2 and G3 within regions of Australia was noted, including in the South West region of Western Australia (WA) during the first reported disease outbreaks in the state’s history. Compared with RRV, the BFV population appeared more stable with less frequent emergence of novel lineages. Preliminary in vitro assessment of RRV and BFV replication kinetics found that RRV replicates at a significantly faster rate and to a higher, more persistent titre compared with BFV, perhaps indicating mosquitoes may be infectious with RRV for longer than with BFV. This investigation resolved a greater diversity of BFV, and a greater understanding of the evolutionary dynamics and history was attained.

Highlights

Barmah Forest virus (BFV), an alphavirus of the Togaviridae family, is one of the most medically significant mosquito-borne viruses of Australia [1]
BFV disease is near indistinguishable on clinical grounds to the disease caused by Ross River virus (RRV), another medically significant Australian alphavirus [2]
BFV was thought to be endemic only to Australia, but has recently been sampled from a viraemic child residing in Papua New Guinea (PNG), without an international travel history [10]

Summary

Introduction

Barmah Forest virus (BFV), an alphavirus of the Togaviridae family, is one of the most medically significant mosquito-borne viruses of Australia [1]. BFV disease is near indistinguishable on clinical grounds to the disease caused by Ross River virus (RRV), another medically significant Australian alphavirus [2]. State Forest in northern Victoria, and concurrently from mosquitoes trapped in Queensland [3,4]. Human disease was first associated with BFV infection in 1988 [5], and several relatively large-scale outbreaks were identified subsequently in the Northern Territory (1992) [6], Western Australia (1993–94) [7], New South Wales (1994–95) [8] and Victoria (2002) [9].

Methods

Results

Conclusion