Immunization With Bovine Herpesvirus-4-Based Vector Delivering PPRV-H Protein Protects Sheep From PPRV Challenge

The Morbillivirus peste des petits ruminants virus (PPRV) is the causal agent of a highly contagious disease that mostly affects sheep and goats and produces considerable losses in developing countries. Current PPRV control strategies rely on live-attenuated vaccines, which are not ideal, as they cannot differentiate infected from vaccinated animals (DIVA). Recombinant vector-based vaccines expressing viral subunits can provide an alternative to conventional vaccines, as they can be easily paired with DIVA diagnostic tools. In the present work, we used the bovine herpesvirus-4-based vector (BoHV-4-A) to deliver PPRV hemagglutinin H antigen (BoHV-4-A-PPRV-H-ΔTK). Vaccination with BoHV-4-A-PPRV-H-ΔTK protected sheep from virulent PPRV challenge and prevented virus shedding. Protection correlated with anti-PPRV IgGs, neutralizing antibodies and IFN-γ-producing cells induced by the vaccine. Detection of antibodies exclusively against H-PPRV in animal sera and not against other PPRV viral proteins such as F or N could serve as a DIVA diagnostic test when using BoHV-4-A-PPRV-H-ΔTK as vaccine. Our data indicate that BoHV-4-A-PPRV-H-ΔTK could be a promising new approach for PPRV eradication programs.

Infectious Agents Identified by Real-Time PCR, Serology and Bacteriology in Blood and Peritoneal Exudate Samples of Cows Affected by Parietal Fibrinous Peritonitis after Caesarean Section

The aim of this study was to identify the pathogens potentially involved in parietal fibrinous peritonitis (PFP). PFP is a complication of laparotomy in cattle, characterized by an accumulation of exudate inside a fibrinous capsule. We have studied 72 cases of PFP in Belgian blue cows, confirmed by a standard diagnostic protocol. Blood was collected to evaluate the presence of antibodies for Mycoplasma bovis(M. bovis), Coxiella burnetii(C. burnetii) and Bovine Herpesvirus 4(BoHV4) by enzyme-linked immunosorbent assays. Peritoneal exudate was obtained from the PFP cavity to perform bacteriological culture, and to identify the DNA of M. bovis, C. burnetii and BoHV4 using real time polymerase chain reaction (qPCR). Bacteriological culture was positive in most peritoneal samples (59/72); Trueperella pyogenes (T. pyogenes) (51/72) and Escherichia coli (E. coli) (20/72) were the most frequently identified. For BoHV4, the majority of cows showed positive serology and qPCR (56/72 and 49/72, respectively). Contrariwise, M. bovis (17/72 and 6/72, respectively) and C. burnetii (15/72 and 6/72, respectively) were less frequently detected (p < 0.0001). Our study proves that PFP can no longer be qualified as a sterile inflammation. Moreover, we herein describe the first identification of BoHV4 and C. burnetii in cows affected by PFP.

Studies on the molecular biological peculiarities of bovine herpesvirus 4

Studies on the molecular biological features of bovine herpesvirus 4 (BHV 4) strains isolated in Bulgaria have been conducted. Two types of polymerase chain reaction have been developed and applied to confirm the gB and TK genes. A restrictase fragment analysis was performed using various types of restrictase enzymes. The tested Bulgarian strains differed in their restrictase genomic profile from the reference European strain Movar 33/63 and from the American strain DN 599, and were clearly different each from the other. No clear relationship has been established between the restrictase enzyme profiles and the tropism of the isolated viruses. Sequencing of isolated ВHV 4 strains showed homo­logy with the reference European strain Movar 33/63. After construction of the phylogenetic tree, three ВHV 4 strains were at one branch of the phylogenetic tree, while two other strains were at the branch of reference Movar 33/63 strain. Applied molecular biology methods can be successfully used for differentiation and detailed genetic characterisation of the isolated BHV 4 strains.

Bovine herpesvirus 4 DNA is not detected in free-ranging domestic cats from California, Colorado or Florida

Objectives Several studies have reported that domestic cats can be naturally infected with bovine herpesvirus 4 (BHV4). Cats experimentally inoculated with BHV4 developed clinical signs involving the urinary tract, leading to the hypothesis that natural infection with BHV4 may be associated with feline lower urinary tract diseases. However, the question of whether BHV4 infection is common in cats remains equivocal. In this study, we sought to determine whether BHV4 is a common natural infection of domestic cats in the USA. Methods We used a sensitive nested PCR protocol specific to the BHV4 thymidine kinase gene to screen free-ranging domestic cat blood DNA samples (n = 101) collected from California, Colorado and Florida. Results Cats within this cohort were positive for seven other common pathogens of domestic cats, demonstrating the relatively high exposure of this population to endemic feline infections. In contrast, all domestic cat blood samples were negative for BHV4, while BHV4-containing tissue culture extracts were strongly positive. Conclusions and relevance BHV4 has been detected in tissues of latently infected cattle, though viral DNA is typically also detected in peripheral blood cells throughout infection. Our results suggest that persistent presence of BHV4 DNA in the blood of domestic cats is either rare or non-existent. We thus conclude that BHV4 is unlikely to be a major pathogen of cats.