The aim of this study was to assess the mechanisms of transmission of bluetongue virus serotype 26 (BTV-26) in goats. A previous study, which investigated the pathogenicity and infection kinetics of BTV-26 in goats, unexpectedly revealed that one control goat may have been infected through a direct contact transmission route. To investigate the transmission mechanisms of BTV-26 in more detail an experimental infection study was carried out in which three goats were infected with BTV-26, three goats were kept uninfected, but were housed in direct contact with the infected goats, and an additional four goats were kept in indirect contact separated from infected goats by metal gates. This barrier allowed the goats to have occasional face-to-face contact in the same airspace, but feeding, watering, sampling and environmental cleaning was carried out separately. The three experimentally infected goats did not show clinical signs of BTV, however high levels of viral RNA were detected and virus was isolated from their blood. At 21 dpi viral RNA was detected in, and virus was isolated from the blood of the three direct contact goats, which also seroconverted. The four indirect barrier contact goats remained uninfected throughout the duration of the experiment. In order to assess replication in a laboratory model species of Culicoides biting midge, more than 300 Culicoides sonorensis were fed a BTV-26 spiked blood meal and incubated for 7 days. The dissemination of BTV-26 in individual C. sonorensis was inferred from the quantity of virus RNA and indicated that none of the insects processed at day 7 possessed transmissible infections. This study shows that BTV-26 is easily transmitted through direct contact transmission between goats, and the strain does not seem to replicate in C. sonorensis midges using standard incubation conditions.

Tuberculosis remains a global health problem so that a more effective vaccine than bacillus Calmette–Guérin is urgently needed. Cytomegaloviruses persist lifelong in vivo and induce powerful immune and increasing (“inflationary”) responses, making them attractive vaccine vectors. We have used an m1–m16-deleted recombinant murine CMV (MCMV) expressing Mycobacterium tuberculosis Ag 85A to show that infection of mice with this recombinant significantly reduces the mycobacterial load after challenge with M. tuberculosis, whereas control empty virus has a lesser effect. Both viruses induce immune responses to H-2d–restricted epitopes of MCMV pp89 and M18 Ags characteristic of infection with other MCMVs. A low frequency of 85A-specific memory cells could be revealed by in vivo or in vitro boosting or after challenge with M. tuberculosis. Kinetic analysis of M. tuberculosis growth in the lungs of CMV-infected mice shows early inhibition of M. tuberculosis growth abolished by treatment with NK-depleting anti–asialo ganglio-N-tetraosylceramide Ab. Microarray analysis of the lungs of naive and CMV-infected mice shows increased IL-21 mRNA in infected mice, whereas in vitro NK assays indicate increased levels of NK activity. These data indicate that activation of NK cells by MCMV provides early nonspecific protection against M. tuberculosis, potentiated by a weak 85A-specific T cell response, and they reinforce the view that the innate immune system plays an important role in both natural and vaccine-induced protection against M. tuberculosis.

The development of safe and effective vaccines against both bovine and human respiratory syncytial viruses (BRSV, HRSV) to be used in the presence of RSV-specific maternally-derived antibodies (MDA) remains a high priority in human and veterinary medicine. Herein, we present safety and efficacy results from a virulent BRSV challenge of calves with MDA, which were immunized with one of three vaccine candidates that allow serological differentiation of infected from vaccinated animals (DIVA): an SH gene-deleted recombinant BRSV (?SHrBRSV), and two subunit (SU) formulations based on HRSV-P, -M2-1, and -N recombinant proteins displaying BRSV-F and -G epitopes, adjuvanted by either oil emulsion (Montanide ISA71VG, SUMont) or immunostimulating complex matrices (AbISCO-300, SUAbis). Whereas all control animals developed severe respiratory disease and shed high levels of virus following BRSV challenge, ?SHrBRSV-immunized calves demonstrated almost complete clinical and virological protection five weeks after a single intranasal vaccination. Although mucosal vaccination with ?SHrBRSV failed to induce a detectable immunological response, there was a rapid and strong anamnestic mucosal BRSV-specific IgA, virus neutralizing antibody and local T cell response following challenge with virulent BRSV. Calves immunized twice intramuscularly, three weeks apart with SUMont were also well protected two weeks after boost. The protection was not as pronounced as that in ?SHrBRSV-immunized animals, but superior to those immunized twice subcutaneously three weeks apart with SUAbis. Antibody responses induced by the subunit vaccines were non-neutralizing and not directed against BRSV F or G proteins. When formulated as SUMont but not as SUAbis, the HRSV N, P and M2-1 proteins induced strong systemic cross-protective cell-mediated immune responses detectable already after priming. ?SHrBRSV and SUMont are two promising DIVA-compatible vaccines, apparently inducing protection by different immune responses that were influenced by vaccine-composition, immunization route and regimen

Members of the family Picornaviridae consist of small positive-sense single-stranded RNA (+ssRNA) viruses capable of infecting various vertebrate species, including birds. One of the recently identified avian picornaviruses, with a remarkably long (>9,040-nucleotide) but still incompletely sequenced genome, is turkey hepatitis virus 1 (THV-1; species Melegrivirus A, genus Megrivirus), a virus associated with liver necrosis and enteritis in commercial turkeys (Meleagris gallopavo). This report presents the results of the genetic analysis of three complete genomes of megriviruses from fecal samples of chickens (chicken/B21-CHV/2012/HUN, GenBank accession no. KF961186, and chicken/CHK-IV-CHV/2013/HUN, GenBank accession no. KF961187) (Gallus gallus domesticus) and turkey (turkey/B407-THV/2011/HUN, GenBank accession no. KF961188) (Meleagris gallopavo) with the largest picornavirus genome (up to 9,739 nucleotides) so far described. The close phylogenetic relationship to THV-1 in the nonstructural protein-coding genome region and possession of the same internal ribosomal entry site type (IVB-like) suggest that the study strains belong to the genus Megrivirus. However, the genome comparisons revealed numerous unique variations (e.g., different numbers of potential 2A peptides, unusually long 3? genome parts with various lengths of a potential second open reading frame, and multiple repeating sequence motifs in the 3? untranslated region) and heterogeneous sequence relationships between the structural and nonstructural genome regions. These differences suggest the classification of chicken megrivirus-like viruses into a candidate novel species in the genus Megrivirus. Based on the different phylogenetic positions of chicken megrivirus-like viruses at the structural and nonstructural genome regions, the recombinant nature of these viruses is plausible. The comparative genome analysis of turkey and novel chicken megriviruses revealed numerous unique genome features, e.g., up to four potential 2A peptides, unusually long 3? genome parts with various lengths containing a potential second open reading frame, multiple repeating sequence motifs, and heterogeneous sequence relationships (possibly due to a recombination event) between the structural and nonstructural genome regions. Our results could help us to better understand the evolution and diversity (in terms of sequence and genome layout) of picornaviruses.