O-antigens present on the surface of Escherichia coli provide antigenic specificity for the strain and are the main components for O-serogroup designation. Serotyping using O-group-specific antisera for the identification of E. coli O-serogroups has been traditionally the gold-standard for distinguishing E. coli strains. Knowledge of the O-group is important for determining pathogenic lineage, classifying E. coli for epidemiological studies, for determining virulence, and for tracing outbreaks of diseases and sources of infection. However, serotyping has limitations, as the antisera generated against each specific O-group may cross-react, many strains are non-typeable, and others can autoagglutinate or be rough (lacking an O-antigen). Currently, the nucleotide sequences are available for most of the 187 designated E. coli O-groups. Public health and other laboratories are considering whole genome sequencing to develop genotypic methods to determine O-groups. These procedures require instrumentation and analysis that may not be accessible and may be cost-prohibitive at this time. In this review, we have identified unique gene sequences within the O-antigen gene clusters and have targeted these genes for identification of O-groups using the polymerase chain reaction. This information can be used to distinguish O-groups by developing other platforms for E. coli diagnostics in the future.

Actinobacillus pleuropneumoniae is a Gram-negative bacterium that belongs to the family Pasteurellaceae. It is the causative agent of porcine pleuropneumonia, a highly contagious respiratory disease that is responsible for major economic losses in the global pork industry. The disease may present itself as a chronic or an acute infection characterized by severe pathology, including hemorrhage, fibrinous and necrotic lung lesions, and, in the worst cases, rapid death. A. pleuropneumoniae is transmitted via aerosol route, direct contact with infected pigs, and by the farm environment. Many virulence factors associated with this bacterium are well characterized. However, much less is known about the role of biofilm, a sessile mode of growth that may have a critical impact on A. pleuropneumoniae pathogenicity. Here we review the current knowledge on A. pleuropneumoniae biofilm, factors associated with biofilm formation and dispersion, and the impact of biofilm on the pathogenesis A. pleuropneumoniae. We also provide an overview of current vaccination strategies against A. pleuropneumoniae and consider the possible role of biofilms vaccines for controlling the disease.

Maternal immunity plays a pivotal role in swine health and production because piglets are born agammaglobulinemic and with limited cell-mediated immunity, i.e. few peripheral lymphoid cells, immature lymphoid tissues, and no effector and memory T-lymphocytes. Swine do not become fully immunologically competent until about 4 weeks of age, which means that their compromised ability to respond to infectious agents during the first month of life must be supplemented by maternal immune components: (1) circulating antibodies derived from colostrum; (2) mucosal antibodies from colostrum and milk; and (3) immune cells provided in mammary secretions. Because maternal immunity is highly effective at protecting piglets against specific pathogens, strengthening sow herd immunity against certain diseases through exposure or vaccination is a useful management tool for ameliorating clinical effects in piglets and delaying infection until the piglets’ immune system is better prepared to respond. In this review, we discuss the anatomy and physiology of lactation, the immune functions of components provided to neonatal swine in mammary secretion, the importance of maternal immunity in the prevention and control of significant pathogens.

The intestine performs the critical roles of nutrient acquisition, tolerance of innocuous and beneficial microorganisms, while retaining the ability to respond appropriately to undesirable microbes or microbial products and preventing their translocation to more sterile body compartments. Various components contribute to antimicrobial defenses in the intestine. The mucus layer(s), antimicrobial peptides and IgA provide the first line of defense, and seek to trap and facilitate the removal of invading microbes. If breached, invading microbes next encounter a single layer of epithelial cells and, below this, the lamina propria with its associated immune cells. The gut immune system has developmental stages, and studies from different species demonstrate that innate capability develops earlier than acquired. In addition, various factors may influence the developmental process; for example, the composition and activity of the gut microbiota, antimicrobials, maternally derived antibodies, host genetics, and various stressors (e.g. feed deprivation). Therefore, it is clear that particularly younger (meat-producing) animals are reliant on innate immune responses (as well as passive immunity) for a considerable period of their productive life, and thus focusing on modulating appropriate innate responses should be an intervention priority. The gut microbiota is probably the most influential factor for immune development and capability. Interventions (e.g. probiotics, prebiotics, antibodies, etc.) that appropriately modulate the composition or activity of the intestinal microbiota can play an important role in shaping the desired functionality of the innate (and acquired) response. In addition, innate immune mediators, such as toll-like receptor agonists, cytokines, etc., may provide more specific ways to suitably modulate the response. A better understanding of mucosal immunology, signaling pathways, and processes, etc., will provide even more precise methods in the future to boost innate immune capability and minimize any associated (e.g. nutrient) costs. This will provide the livestock industry with more effective options to promote robust and efficient productivity.

All sectors of livestock production are in the process of shifting from small populations on many farms to large populations on fewer farms. A concurrent shift has occurred in the number of livestock moved across political boundaries. The unintended consequence of these changes has been the appearance of multifactorial diseases that are resistant to traditional methods of prevention and control. The need to understand complex animal health conditions mandates a shift toward the collection of longitudinal animal health data. Historically, collection of such data has frustrated and challenged animal health specialists. A promising trend in the evolution toward more efficient and effective livestock disease surveillance is the increased use of aggregate samples, e.g. bulk tank milk and oral fluid specimens. These sample types provide the means to monitor disease, estimate herd prevalence, and evaluate spatiotemporal trends in disease distribution. Thus, this article provides an overview of the use of bulk tank milk and pen-based oral fluids in the surveillance of livestock populations for infectious diseases.

Neutrophilic bronchiolitis is the primary lesion in asthma-affected horses. Neutrophils are key actors in host defense, migrating toward sites of inflammation and infection, where they act as early responder cells toward external insults. However, neutrophils can also mediate tissue damage in various non-infectious inflammatory processes. Within the airways, these cells likely contribute to bronchoconstriction, mucus hypersecretion, and pulmonary remodeling by releasing pro-inflammatory mediators, including the cytokines interleukin (IL)-8 and IL-17, neutrophil elastase, reactive oxygen species (ROS), and neutrophil extracellular traps (NETs). The mechanisms that regulate neutrophil functions in the tissues are complex and incompletely understood. Therefore, the inflammatory activity of neutrophils must be regulated with exquisite precision and timing, a task achieved through a complex network of mechanisms that regulates neutrophil survival. The discovery and development of compounds that can help regulate ROS, NET formation, cytokine release, and clearance would be highly beneficial in the design of therapies for this disease in horses. In this review, neutrophil functions during inflammation will be discussed followed by a discussion of their contribution to airway tissue injury in equine asthma.

In dairy herds, application of antimicrobials at drying-off is a common mastitis control measure. This article describes a protocol for systematic review and meta-analysis to address three crucial points regarding antimicrobial usage at drying-off: (1) comparative efficacy of antimicrobials used for preventing new and eliminating existing intramammary infections (IMI); (2) comparison of selective and blanket dry cow therapy approaches in preventing new and eliminating existing IMI; and (3) assessment of the extra prevention against new IMI that can be gained from using antimicrobial-teat sealant combinations versus antimicrobials alone. Five PICO (Population, Intervention, Comparator, Outcome) questions were formulated to cover the three objectives of the review. Medline, CAB Abstracts, Web of Science, and conference proceedings will be searched along with iterative screening of references. Articles will be eligible if: (1) published after 1966; (2) written in English or French; and (3) reporting field clinical trials and observational studies, conducted on dairy cows at drying-off, with at least one antimicrobial-treated group and one IMI-related outcome. Authors will independently assess the relevance of titles and abstracts, extract data, and assess bias and the overall quality of evidence. Results will be synthesized and analyzed using pairwise and network meta-analysis. The proposed study will significantly update previously conducted reviews.