Sunguru virus: a novel virus in the family Rhabdoviridae isolated from a chicken in north-western Uganda

Abstract

Sunguru virus (SUNV), a novel virus belonging to the highly diverse Rhabdoviridae family, was isolated from a domestic chicken in the district of Arua, Uganda, in 2011. This is the first documented isolation of a rhabdovirus from a chicken. SUNV is related to, but distinct from, Boteke virus and other members of the unclassified Sandjimba group. The genome is 11056 nt in length and contains the five core rhabdovirus genes plus an additional C gene (within the ORF of a phosphoprotein gene) and a small hydrophobic protein (between the matrix and glycoprotein genes). Inoculation of vertebrate cells with SUNV resulted in significant viral growth, with a peak titre of 7.8 log10 p.f.u. ml(-1) observed in baby hamster kidney (BHK) cells. Little to no growth was observed in invertebrate cells and in live mosquitoes, with Anopheles gambiae mosquitoes having a 47.4% infection rate in the body but no dissemination of the virus to the salivary glands; this suggests that this novel virus is not arthropod borne as some other members of the family Rhabdoviridae.

Fig. 1

SUNV genome organization. (a) Schematic representation of the genome showing the seven open reading frames (ORFs) of the N, P, M, SH, G, L and overlapping C gene. (b) Transcription initiation, intergenic and transcription termination sequences. Start and stop codons are in bold type. Leader and trailer sequences are shown depicting end complementarity. n.a, Not applicable.

Fig. 2

Phylogenetic relationship of SUNV (accession KF395226) with other representatives of the family Rhabdoviridae. The trees were generated by aligning the available amino acid sequences for the L (a) and N (b) proteins (see Fig. 2 Supplement available in the online Supplementary Material) using the maximum-likelihood method and Jones–Taylor–Thorton substitution model. Bootstrap values were determined using 1000 replicates and are listed at each node. Gaps in the alignment were analysed by partial deletion, which resulted in 136 and 298 positions for the L and N protein trees, respectively, in the final dataset. See Fig. 2 Supplement for accession numbers and abbreviations. The scale bars represent the number of amino acid substitutions per horizontal distance. ^aNot found in the ICTV database.

Fig. 3

Growth of SUNV in (a) vertebrate and (b) invertebrate cell lines. Each point on the graph represents the mean of two replicates and the error bars signify one standard deviation.