Co-infection of Mammalian orthorubulavirus 5 and Mammalian orthoreovirus
type-3 in domestic pigs in India
Abstract
During a routine surveillance for exotic and emerging swine viral
diseases in India, five samples (four faecal, one serum) showed
cytopathic effects in Vero cells. Transmission electron microscopy of
infective cell supernatant revealed the presence of two types of
virions. De novo metavirome sequencing enabled complete genome
assembly of Mammalian orthorubulavirus 5 (MRuV5) and Mammalian
orthoreovirus (MRV). The MRuV5 isolates possessed a whole genome of
15246 bp with seven genes (NP, V/P, M, F, SH, HN, L), while the MRV
isolates had segmented genome with three large (L1, L2, L3), three
medium (M1, M2, M3) and four small (S1, S2, S3, S4) segments. The MRuV5
isolates were genetically grouped with those from various mammalian
species reported from South Korea and China. Deduced amino acid
sequences of the HN, NP and F gene coding regions of MRuV5 isolates
showed the substitutions of three (92L, 111R, 447H), two (86S, 121S) and
two (139T, 246T) amino acids, respectively, compared to previously
reported strains of the virus. However, they did not reveal any change
in predicted amino acid residues at the receptor binding site in HN
protein, cleavage site or HN stalk region. S1 gene of the MRV isolates
showed the highest nucleotide identity (97.73%) with the MRV3 strain
ZJ2013 isolated from pig in China, and these isolates were grouped into
MRV type-3. Deduced amino acid sequences of MRV3 S1 gene revealed amino
acid residues 198-204NLAIRLP, 249I, 340D, 419E known for sialic acid
binding site and neurotropism. We report the co-infection of MRuV5 and
MRV3 detected incidentally for the first time in domestic pigs in India.
Although MRuV5 and MRV3 develop asymptomatic infections or mild disease
in animals and humans, continuous monitoring of evolution and spread of
such viruses is important in the current global scenario of increasing
threats due to emerging novel pathogens.