Phylogenetic analysis of canine distemper virus in South African wildlife.

Angelika K Loots,Desiré Lee Dalton,Emily Mitchell,Antoinette Kotze,Prudent S Mokgokong,Estelle H Venter,Naomi Forrester

doi:10.1371/journal.pone.0199993

Abstract

Canine distemper virus (CDV) causes a severe contagious disease in a broad range of hosts. This is the first study to genetically characterise CDV strains from four different wildlife species in South Africa. The phylogenetic diversity of CDV is examined, using the haemagglutinin gene. The South African wildlife CDV isolates showed a high degree of similarity to CDV in South African domestic dogs. Phylogenetic analyses confirmed the presence of 12 geographical lineages with CDV strains from South African wildlife falling within the Southern African lineage. The study reveals two possible co-circulating sub-genotypes corresponding to the northern and southern regions of South Africa respectively. CDV strains from the non-canid species were distinct, but similar to CDV isolates from domestic dog and wild canids. Residues at amino acid sites of the SLAM binding region support the notion that CDV strains encoding 519I / 549H are better adapted to non-canid species than canid species. The amino acids present at site 530 are conserved regardless of host species. Strains from South African wild carnivores showed no difference between host species with all strains presenting 530N. All non-canid strains in this study presented the combination 519I/549H. No evidence of host adaptation or lineage grouping was observed for the Nectin-4 binding region. Further studies should include CDV strains isolated from various hosts from a wider geographical range in South Africa.

Highlights

Canine distemper virus (CDV; family Paramyxoviridae, genus Morbillivirus) is a singlestranded, enveloped RNA virus that is reported to cause a severe systemic disease called canine distemper (CD) globally [1]
The H-protein is involved in cell tropism and is associated with host shift and adaptability, due to its ability to attach to cellular receptors such as the signalling lymphocyte activation molecule (SLAM, CD150), and Nectin-4 (PVRL4), facilitating viral entry [25,26] (
A 1815 base pair fragment of the CDV Haemmaglutinin gene (H-gene), which includes the SLAM and Nectin-4 binding regions, was amplified and sequenced for 12 clinical specimens obtained from seven AWD, one domestic dog, one spotted hyena, two lions and one brown hyena (Table 1)

Summary

Introduction

Canine distemper virus (CDV; family Paramyxoviridae, genus Morbillivirus) is a singlestranded, enveloped RNA virus that is reported to cause a severe systemic disease called canine distemper (CD) globally [1]. Genetic lineages largely follow a geographical pattern and include America I, America II, Asia I and II, South America I/ Europe, Europe wildlife, South America II, South America III/Columbian, Arctic-like, Rockborn-like, South Africa and East Africa [11,12,14,15,16,17,18,19,20,21] These lineages are distinguished on the basis of strains falling within the same clade showing an amino acid divergence of less than 4% in their H-protein region [11,22,23]. Amino acids of the H-protein considered responsible for viral attachment to the Nectin-4 receptor (478, 479, 537, and 539) [32,33] showed no evidence for adaptation to non-canid or canid hosts [12]

Methods

Results

Conclusion