Myxoma virusjumps species to the Iberian hare

Abstract

The study of myxoma virus (MYXV) infections in the European rabbit (Oryctolagus cuniculus) has produced one of the most accepted host–pathogen evolutionary models. To date, myxomatosis has been limited to the European rabbit with sporadic reports in hares. However, reports of widespread mortalities in the Iberian hare (Lepus granatensis) with myxomatosis‐like clinical signs indicate a potential species jump has occurred. The presence of MYXV DNA was confirmed by PCR in 244 samples received from regional veterinary services, animal health laboratories, hunters or rangers over a 5‐month period. PCR analysis of 4 MYXV positive hare samples revealed a 2.8 kb insertion located within the M009 gene with respect to MYXV. The presence of this insertion was subsequently confirmed in 20 samples from 18 Spanish provinces. Sanger sequencing and subsequent analysis show that the insert contained 4 ORFs which are phylogenetically related to MYXV genes M060, M061, M064 and M065. The complete MYXV genome from hare tissue was sequenced using Ion torrent next‐generation technology and a summary of the data presented here. With the exception of the inserted region, the virus genome had no large scale modifications and 110 mutations with respect to the MYXV reference strain Lausanne were observed. The next phase in the evolution of MYXV has taken place as a host species jump from the European rabbit to the Iberian hare an occurrence which could have important effects on this naïve population.

Detection of Recombinant Hare Myxoma Virus in Wild Rabbits (Oryctolagus cuniculus algirus)

“…The rabbits were tested for rabbit haemorrhagic disease virus 2 (RHDV2) and MYXV by real time PCR targeting the M000.5 L/R gene [ 17 , 18 ]. The 2.8 kbp insert was investigated by the system described by Dalton et al [ 15 ] using primers 9A/9B and 9E/9F that flank the insertion, allowing the amplification of a 3.1 or 4.6 kbp region in recombinant MYXV or a 300 bp region (absence of insert, using the oligomers 9E/9F) in MYXV. Amplification reactions were carried out in a Bio-Rad CFX96™ Thermal Cycler (Bio-Rad Laboratories Srl, Redmond, USA), using the One Step RT-PCR kit (Qiagen, Hilden, Germany) for RHDV2, and the HighFidelity PCR Master Mix (Roche Diagnostics GmbH, Mannheim, Germany), for MYXV and recombinant MYXV.…”

“…The emergence of myxomatosis in the Iberian hare in mid 2018, was caused by a recombinant myxoma virus (first designated as MYXV-Tol, and subsequently ha-MYXV considering its modified tropism towards hares), harbouring an insertion of about 2.8 kbp [ 13 , 14 , 15 , 16 ]. After this, health surveillance in the Iberian hare within the scope of Project +Coelho (investigating MYXV [ 17 ], RHDV2 [ 18 ] and LeHV-5 [ 19 ]) and in the wild rabbit (investigating MYXV and RHDV2 [ 18 ]) was extended to include screening for ha-MYXV as described by Dalton et al [ 15 ].…”

Coinfections of Novel Polyomavirus, Anelloviruses and a Recombinant Strain of Myxoma Virus-MYXV-Tol Identified in Iberian Hares

“…Following purification, the genome of the MYXV was sequenced using high-throughput sequencing, which led to the identification of the recombinant region (~2.8 kb) derived from an unknown poxvirus in the MYXV genome and thus the recombinant strain, MYXV-Tol [8]. Following this report, other studies [9,10] also identified the MYXV containing the same novel~2.8 kb recombinant region.…”

“…Hare populations have declined since the late 1960s which is thought to be in part due to disease [7,51,52]. The recent documentation of an outbreak of myxoma virus in hares caused by a prevalent recombinant MYXV-Tol [8][9][10] highlights another threat to the species. As an important food source for many predator species, such as the endangered Iberian lynx (Lynx pardinus), evaluating circulating pathogen populations and monitoring disease spread as well as spillover of pathogens is crucial for the survival of the hare and other species higher on the trophic cascade.…”

“…The genome of the recombinant MYXV-Tol identified in Iberian hares is~99% similar to MYXV variants/strains previously reported circulating in European rabbits, with the exception of a recombinant region~2800 bp in length and three disrupted genes (M009L, M036L and M152R). The recombinant region encodes four additional open reading frames (ORFs), which were more closely related, but not identical, to the MYXV proteins encoded by M060R, M061R, M064R and M065R genes [8][9][10].…”