Phylogenetic analysis of SRLV sequences from an arthritic sheep outbreak demonstrates the introduction of CAEV-like viruses among Spanish sheep

Abstract

Small ruminant lentiviruses (SRLV) cause different clinical forms of disease in sheep and goats. So far in Spain, Maedi visna virus-like (MVV-like) sequences have been found in both species, and the arthritic SRLV disease has never been found in sheep until a recent outbreak. Knowing that arthritis is common in goats, it was of interest to determine if the genetic type of the virus involved in the sheep arthritis outbreak was caprine arthritis encephalitis viruslike (CAEV-like) rather than MVV-like. Alignment and phylogenetic analyses on nucleotide and deduced amino acid sequences from SRLV of this outbreak, allowed a B2 genetic subgroup assignment of these SRLV, compatible with a correspondence between the virus genetic type and the disease form. Furthermore, an isolate was obtained from the arthritic outbreak, its full genome was CAEV-like but the pol integrase region was MVV-like. Although its LTR lacked a U3 repeat sequence and had a deletion in the R region, which has been proposed to reduce viral replication rate, its phenotype in sheep skin fibroblast cultures was rapid/high, thus it appeared to have adapted to sheep cells. This outbreak study represents the first report on CAEV-like genetic findings and complete genome analysis among Spanish small ruminants.

Ovine TRIM5α Can Restrict Visna/Maedi Virus

“…Such variation was higher than expected given that sheep and goats diverged 6 million years ago (16), whereas humans and chimpanzees, which encode more highly related TRIM5␣ sequences, diverged 7 million years ago (5). The close relatedness between sheep and goats is consistent with the ability of sheep (VMV) and goat (CAEV) lentiviruses to infect both ruminant species (8,32). The high variability of both PRYSPRY (6, 34; this work) and CA of SRLV (7,26) may account for the evolution of both virus and host, involving TRIM5␣ and CA interactions, as described for primate lentiviruses (11,28,34,38).…”

Small Ruminant Lentivirus–Induced Arthritis

“…Additionally, a representative strain of the outbreak was isolated from sheep No. 3 (strain 496), fully sequenced (Genbank FJ195346) and characterized, reinforcing the B2 linking of the infecting virus, 11 closer to other CAEVlike SRLVs than to classical VMV-like lentiviruses. This is in contrast with other previous isolates in Spain that belonged to A and D VMV-like groups.…”

“…3) confirmed the outbreak to be caused by a B2 genotype SRLV. 11 Given the similar pathologic features among them, the geographic clustering, and the presence of SRLV-infected goats in the 5 flocks studied, it is assumed that this pathology represents an outbreak caused by a interspecies transmission of SRLV between goats and sheep.…”

Sequence comparison on gag gene of caprine arthritis encephalitis virus from Korea

“…1, 2). Sequences of the nested PCR product showed about 92.4% homology of this region with the standard strain CAEV Cork and with other isolates from Brazil, China, Thailand, and Spain were 92.4, 94.1, 94.6, 91.4, and 89.2%, respectively [14][15][16]. Comparison with other related isolates, It585, It-Pi1 and It-047g05, revealed 90.8, 89.2 and 90.3% identity, respectively.…”