Abstract:
Encephalomyocarditis virus (EMCV) outbreaks are rare in southern Africa. Only two have
been reported to date from South Africa, both coinciding with rodent irruptions. The first
outbreak manifested as acute myocarditis in pigs in 1979, whilst the second, occurring
from 1993 to 1994, was linked to the deaths of 64 free-ranging adult African elephants
(Loxodonta africana). The P1 genome region, inclusive of the flanking leader (L) and 2A
genes, of three South African isolates, one from swine and two from elephants, was
characterised by PCR amplification and sequencing of up to 11 overlapping fragments. In
addition to the resulting 3329 nucleotide dataset, the 3D region that is widely used in
molecular epidemiology studies, was characterised, and three datasets (P1, VP1/3 and 3D),
complemented with available homologous EMCV data, were compiled for analyses.
Phylogenetic inferences revealed the near-identical elephant outbreak strains to be most
closely related to a mengovirus from rhesus macaques (Macaca mulatta) in Uganda,
differing from the latter by between 11% (3D) and 15% (VP3/1). The South African pig
isolate differed by 4% (3D) and 11% (VP3/1) from available European and Asian pig virus
sequences. This study confirms the presence of two genetically distinct EMCV lineages
recovered from sporadic outbreaks in wild and domestic hosts in southern Africa, and
provides valuable baseline data for future outbreak eventualities in the sub-region.
