In the course of investigating the malignant catarrhal fever (MCF) subgroup of rhadinoviruses, seven novel rhadinoviruses were identified in a variety of ruminants, including domestic sheep, bighorn sheep, bison, black-tailed deer, mule deer, fallow deer, elk and addax. Based on the DNA polymerase gene sequences, these newly recognized viruses clustered into a second distinct subgroup in ruminants with three members identified previously in cattle, goats and oryx. Phylogenetic analysis revealed that the currently known ruminant rhadinoviruses appear to comprise three distinct genetic lineages: (i) the MCF subgroup, defined by sequence identity and the presence of the 15A antigenic epitope; (ii) a second distinct subgroup, devoid of the 15A epitope, which contains the previously reported bovine lymphotropic herpesvirus and related viruses; and (iii) a third distinct subgroup represented by Bovine herpesvirus 4. Comparison of phylogenetic trees between the rhadinoviruses and their corresponding hosts further supports the gammaherpesvirus and host co-evolution theory.

No abstract

An avian-like H3N2 influenza A virus (IAV) has recently caused sporadic canine influenza outbreaks in China and Korea, but the molecular mechanisms involved in the interspecies transmission of H3N2 IAV from avian to canine species are not well understood. Sequence analysis showed that residue 222 in haemagglutinin (HA) is predominantly tryptophan (W) in the closely related avian H3N2 IAV, but was leucine (L) in canine H3N2 IAV. In this study, reassortant viruses rH3N2-222L (canine-like) and rH3N2-222W (avian-like) with HA mutation L222W were generated using reverse genetics to evaluate the significance of the L222W mutation on receptor binding and host tropism of H3N2 IAV. Compared with rH3N2-222W, rH3N2-222L grew more rapidly in MDCK cells and had significantly higher infectivity in primary canine tracheal epithelial cells. Tissue-binding assays demonstrated that rH3N2-222L had a preference for canine tracheal tissues rather avian tracheal tissues, whereas rH3N2-222W favoured slightly avian rather canine tracheal tissues. Glycan microarray analysis suggested both rH3N2-222L and rH3N2-222W bound preferentially to a2,3-linked sialic acids. However, the rH3N2-222W had more than twofold less binding affinity than rH3N2-222L to a set of glycans with Neu5Aca2-3Galb1-4(Fuca-)-like or Neu5Aca2-3Galb1-3(Fuca-)-like structures. These data suggest the W to L mutation at position 222 of the HA could facilitate infection of H3N2 IAV in dogs, possibly by increasing the binding affinities of the HA to specific receptors with Neu5Aca2-3Galb1-4(Fuca-) or Neu5Aca2-3Galb1-3(Fuca-)-like structures that are present in dogs.

Given their free-ranging habits, feral swine could serve as reservoirs or spatially dynamic 'mixing vessels' for influenza A virus (IAV). To better understand virus shedding patterns and antibody response dynamics in the context of IAV surveillance amongst feral swine, we used IAV of feral swine origin to perform infection experiments. The virus was highly infectious and transmissible in feral swine, and virus shedding patterns and antibody response dynamics were similar to those in domestic swine. In the virus-inoculated and sentinel groups, virus shedding lasted #6 and #9 days, respectively. Antibody titres in inoculated swine peaked at 1 : 840 on day 11 post-inoculation (p.i.), remained there until 21 days p.i. and dropped to ,1 : 220 at 42 days p.i. Genomic sequencing identified changes in wildtype (WT) viruses and isolates from sentinel swine, most notably an amino acid divergence in nucleoprotein position 473. Using data from cell culture as a benchmark, sensitivity and specificity of a matrix gene-based quantitative reverse transcription-PCR method using nasal swab samples for detection of IAV in feral swine were 78.9 and 78.1 %, respectively. Using data from haemagglutination inhibition assays as a benchmark, sensitivity and specificity of an ELISA for detection of IAV-specific antibody were 95.4 and 95.0 %, respectively. Serological surveillance from 2009 to 2014 showed that ,7.58 % of feral swine in the USA were positive for IAV. Our findings confirm the susceptibility of IAV infection and the high transmission ability of IAV amongst feral swine, and also suggest the need for continued surveillance of IAVs in feral swine populations.

Barbed Glycomer™ 631 closures had a significantly lower maximum load at failure and stiffness, and higher average tissue reaction scores, but showed no difference in short term outcome for intradermal closure of dorsally located skin incisions in dogs.