Abstract:
From 1993 to 1994, 64 free-ranging elephants (Loxodonta africana) succumbed to encephalomyocarditis in the Kruger National Park, South Africa, of which 83% were adult bulls.
Mastomys rodents were implicated as the reservoir host of the Encephalomyocarditis virus (EMCV)
based on serology and RT-PCR. However, in the absence of sequence-confirmation of both the virus
and the rodent host, definitive links between the elephant outbreak strains and rodent reservoir
could not be established. In this study, we generate the first reference genome sequences for three
historical EMCVs isolated from two Mastomys rodents and one Mastomys-associated mite, Laelaps
muricola, in Gauteng Province, South Africa, in 1961. In addition, near-complete genome sequences
were generated for two elephant outbreak virus strains, for which data were previously limited to
the P1 and 3D genome regions. The consensus sequence of each virus was determined using a PCRSanger sequencing approach. Phylogenetic analysis confirmed the three near-identical (99.95–99.97%)
Mastomys-associated viruses to be sister to the two near-identical (99.85%) elephant outbreak strains,
differing from each other at 6.4% of sites across the ~7400-nucleotide region characterised. This study
demonstrates a link between Mastomys-associated viruses and the historical elephant outbreak strains
and implicates Mastomys as reservoirs of EMCV in South Africa.
