11/14/2024


In summary, our study demonstrated that oral immunization with L. acidophilus-S1 could improve the humoral and mucosal immune levels in sows and would be a promising candidate vaccine against PEDV infection in piglets.It is generally accepted that as bovine respiratory disease (BRD) develops, bacterial pathogens first proliferate in the nasopharynx and then colonize the lungs, leading to bronchopneumonia. However, such temporal changes have never been definitively demonstrated. Therefore, the objective was to describe the progression of the nasopharyngeal and tracheal bacterial microbiotas of feedlot cattle during development of BRD. Nasopharyngeal swabs and tracheal wash samples were collected from 24 heifers over 20 d after arrival at a feedlot. Heifers were assessed daily and sampled based on reticulo-rumen/rectal temperatures and development of clinical signs of BRD. The study end point for each heifer was either at BRD treatment (BRD group; n = 15) or day 20 if the heifer remained healthy or did not meet BRD treatment criteria (TOL group; n = 9). Total DNA was extracted from each sample and the 16S rRNA gene (V3-V4) sequenced. Alpha and beta diversity were compared between BRD-TOL groups and sampling locations over time. There were no common patterns of change over time in composition or diversity of either the nasopharyngeal or tracheal bacterial microbiotas of cattle that developed BRD. Health status affected bacterial composition (R2 = 0.043; less then 0.001), though this effect was low compared to variation among individual animals (R2 = 0.335; less then 0.001) and effects of days on feed (R2 = 0.082; less then 0.001). Specific bacterial taxa (Moraxella and Mycoplasma dispar) nevertheless appeared to have a potential role in respiratory health.Bluetongue (BT) is an arbovirus-borne disease of ruminants caused by bluetongue virus (BTV) that has the potential to have a serious economic impact. Currently available commercial vaccines include attenuated vaccines and inactivated vaccines, both of which have achieved great success in the prevention and control of BTV. However, these vaccines cannot distinguish between infected animals and immunized animals. To control outbreaks of BTV, the development of labeled vaccines is urgently needed. In this study, we used the plasmid-based reverse genetics system (RGS) of BTV to rescue four recombinant viruses in which HA (influenza hemagglutinin) tags were inserted at different sites of VP2. In vitro, the recombinant tagged viruses exhibited morphologies, plaque, and growth kinetics similar to the parental BTV-16, and expressed both VP2 and HA tag. Subsequently, the selected recombinant tagged viruses were prepared as inactivated vaccines to immunize IFNAR(-/-) mice and sheep, and serological detection results of anti-HA antibody provided discriminative detection. In summary, we used plasmid-based RGS to rescue BTV recombinant viruses with HA tags inserted into VP2, and detected several sites on VP2 that can accommodate HA tags. Some of the recombinant tagged viruses have potential to be developed into distinctive inactivated vaccines.Porcine circovirus type 3 (PCV3) is a new member of Circovirus, which could cause various symptoms in infected pigs. It has been reported in many countries and detected from various animals. This study retrospectively analyzed serum samples that were randomly collected from 1,499 clinically healthy cattle in Shandong province from 2011 to 2018. https://www.selleckchem.com/products/glafenine.html The PCV3 DNA was detected in 28.95% (434/1,499) of samples. Twenty-seven cap genes of PCV3 were sequenced and compared with seventy reference sequences. They were in several different branches, but all belonged to PCV3b. The results indicated that PCV3 was prevalent in health cattle in Shandong province of China. Though infected cattle did not show any clinical symptoms, they could be a reservoir for the virus and probably transferred them back to pigs.This study investigated the association of Pasteurella multocida isolation and the molecular characteristics of the isolates with the presence of pneumonic lesions in lambs at slaughter to assess its importance as a causative agent of pneumonic pasteurellosis compared with Mannheimia haemolytica. P. multocida was isolated from the 13.9% and 2.7%, and M. haemolytica from the 36.4% and 26.8%, of lungs with and without lesions, respectively (P less then 0.05). Both microorganisms were frequently coisolated (23.2% and 12.5% from lungs with and without lesions, respectively). Isolation of P. multocida alone exhibited greater strength of association with pneumonic lesions (OR 11.4; 95% CI 3.2-40.6) than that exhibited by M. haemolytica alone (OR 3.0; 95% CI 1.6-5.4). Cluster analysis grouped the lungs into four clusters characterized by the isolation of M. haemolytica or P. multocida alone (clusters 1 and 4), coisolation of both microorganisms (cluster 3), and isolation of neither (cluster 2). Cluster 4 lungs exhibited higher frequencies of pneumonic lesions (87.5%) and severe (20.8%) and moderate (25.0%) lesions. Lungs coinfected with both pathogens (cluster 3) did not exhibit a higher frequency of severe and moderate consolidation lesions (6.1% and 14.3%, respectively), suggesting that P. multocida and M. haemolytica do not act synergically to cause more severe pneumonic infections. The greater strength of association of P. multocida isolation with pneumonic lesions together with the higher severity of the lesions caused could indicate a greater role played by this pathogen in the aetiopathogenesis of pneumonic pasteurellosis in sheep than is commonly assumed.In December 2018, suspected outbreaks of equine influenza (EI) were observed in donkeys in Sokoto State, in the extreme northwest of Nigeria bordering the Republic of the Niger. Equine influenza virus (EIV) subtype H3N8 was the etiologic agent identified in the outbreaks using real-time RT-qPCR and sequencing of both the partial haemagglutinin (HA) gene and the complete genome. Since then the H3N8 virus spread to 7 of the 19 northern states of Nigeria, where it affected both donkeys and horses. Phylogenetic analysis of the partial and complete HA gene revealed the closest nucleotide similarity (99.7%) with EIVs belonging to the Florida clade 1 (Fc-1) of the American lineage isolated in 2018 from Argentina and Chile. In total, 80 amino acid substitutions were observed in the viral proteins when compared to the OIE-recommended Fc-1 vaccine strains. The HA and neuraminidase proteins respectively had 13 and 16 amino acid substitutions. This study represents the first reported outbreak of EI caused by an Fc-1 virus in Nigeria and in the West Africa sub-region.