The One Health European Joint Programme (OHEJP), 2018-2022: an exemplary One Health initiative

OverviewOne Health is an increasingly popular approach used to tackle complex health problems. The One Health concept recognizes that human health is tightly connected to the health of animals and the environment. Although the related fields are now more aware of the benefits of collaborative working, the full benefits have not yet been realized as research efforts are often focussed on just one of these health domains. To address regional and global issues such as foodborne zoonoses (FBZ), antimicrobial resistance (AMR) and emerging infectious threats (ET), there must be transdisciplinary collaboration between the health domains, in addition to active dialogue between scientists and international policy makers. This editorial introduces the One Health European Joint Programme (OHEJP) as an example of a One Health initiative.Zoonoses, AMR and their global burdenZoonoses are infectious diseases that can be transmitted directly or indirectly between humans and animals. Although the severity of zoonotic infections varies, their global impact is undisputable. The World Bank estimates that just six zoonotic disease outbreaks between 1997 and 2009 led to a global economic loss of US$80 billion [1]. This high cost is due to medical costs, loss of individual productivity and restrictions on trade and movement during outbreaks. Despite improvements in the management and treatment of zoonotic outbreaks, high disease burdens caused by zoonotic pathogens continue to be reported globally. These problems have been amply demonstrated recently by the SARS-CoV-2 pandemic. Although it is still too soon to fully assess the total economic and societal cost of this virus, recent publications, such as Nicola et al. [2] have begun to highlight just how widespread the impact of a truly global zoonotic disease can be.Alongside zoonoses, AMR is a growing international issue. The World Health Organization (WHO) has listed AMR as one of the ten greatest global health threats in 2019 [3]. AMR is defined as the ability of microorganisms to survive the effect of antimicrobial drugs, hindering not only our ability to treat infectious diseases, but also to perform medical procedures requiring prophylactic antibiotic administration. It has been predicted that by 2050, the number of deaths due to unresponsive infections will reach 10 million annually, with the associated costs being estimated at US$ 100 trillion [4]. Increased and inappropriate use of antimicrobials has contributed to the development and spread of AMR, which can be transmitted between humans, animals and the environment.The history of the ‘One Health’ conceptThe origins of One Health go as far back as 1855, when Rudolf Virchow founded comparative pathology, which could be seen as the origin of the One Health concept. Building upon this, Calvin W. Schwabe argued in the twentieth century against compartmentalization in medical research, using the term ‘One Medicine’. The term One Health was then popularized in 2004 by the Wildlife Conservation Society at a conference in New York [5], and its use has continued to evolve since then, fostering the revival of comparative medicine (Fig. 1, and reviewed in Gibbs [6]). One Health has now been adopted by the WHO [7], the Food and Agriculture Organization (FAO) [8] and the World Organization for Animal Health (OIE) [9]

Impact of dietary organic acids and botanicals on intestinal integrity and inflammation in weaned pigs

BACKGROUND: Organic acids, such as citric and sorbic acid, and pure plant-derived constituents, like monoterpens and aldehydes, have a long history of use in pig feeding as alternatives to antibiotic growth promoters. However, their effects on the intestinal barrier function and inflammation have never been investigated. Therefore, aim of this study was to assess the impact of a microencapsulated mixture of citric acid and sorbic acid (OA) and pure botanicals, namely thymol and vanillin, (PB) on the intestinal integrity and functionality of weaned pigs and in vitro on Caco-2 cells. In the first study 20 piglets were divided in 2 groups and received either a basal diet or the basal diet supplemented with OA + PB (5 g/kg) for 2 weeks post-weaning at the end of which ileum and jejunum samples were collected for Ussing chambers analysis of trans-epithelial electrical resistance (TER), intermittent short-circuit current (I(SC)), and dextran flux. Scrapings of ileum mucosa were also collected for cytokine analysis (n = 6). In the second study we measured the effect of these compounds directly on TER and permeability of Caco-2 monolayers treated with either 0.2 or 1 g/l of OA + PB. RESULTS: Pigs fed with OA + PB tended to have reduced I(SC) in the ileum (P = 0.07) and the ileal gene expression of IL-12, TGF-β, and IL-6 was down regulated. In the in vitro study on Caco-2 cells, TER was increased by the supplementation of 0.2 g/l at 4, 6, and 14 days of the experiment, whereas 1 g/l increased TER at 10 and 12 days of treatment (P < 0.05). Dextran flux was not significantly affected though a decrease was observed at 7 and 14 days (P = 0.10 and P = 0.09, respectively). CONCLUSIONS: Overall, considering the results from both experiments, OA + PB improved the maturation of the intestinal mucosa by modulating the local and systemic inflammatory pressure ultimately resulting in a less permeable intestine, and eventually improving the growth of piglets prematurely weaned

Lactobacilli probiotics as a potential control for avian intestinal spirochaetosis.

Brachyspira are the causative agent of avian intestinal spirochaetosis, a gastrointestinal disease common in layer hens and broiler breeders. This disease costs the UK laying industry approximately £18 million per annum, resulting from reduced egg production and poor egg quality. Prevalence of Brachyspira is increasing, and due to the poor understanding of this pathogen, mitigation strategies have been largely unsuccessful. Therefore, preventative measures are essential. These studies aimed to improve the understanding of Brachyspira pathobiology and investigate Lactobacillus probiotics as a suitable mitigation strategy. Brachyspira and Lactobacillus species were characterised using phenotypic and genotypic methods. Four Lactobacillus isolates were selected for their inhibition of Brachyspira in vitro and demonstrated inhibition by a number of mechanisms. Secreted metabolites in Lactobacillus cell free supernatant inhibited Brachyspira (p value < 0.05) and metabolomic studies identified the production of organic acids to be a major contributor to inhibition. Protein denaturation in cell free supernatants significantly reduced Brachyspira inhibition (p value < 0.05), suggesting the role of bacteriocins in inhibition. Furthermore, L. reuteri isolates co-aggregated with Brachyspira in vitro, reducing pathogen viability (p value < 0.05). Pro-inflammatory responses to Brachyspira in HD11 avian macrophages were dominated by upregulation of IFNg (p value < 0.01) and pre-treatment of cells with Lactobacillus significantly reduced this response (p value < 0.0001), demonstrating the ability of probiotics to alter immune responses to Brachyspira. Galleria mellonella were utilised to study Brachyspira virulence and probiotic intervention. G. mellonella exhibited a varied response to Brachyspira iv infection and Lactobacillus isolates were able to protect against the mortality associated with Brachyspira isolates (p value < 0.05). The studies here demonstrated that Lactobacillus probiotics are a suitable mitigation strategy against Brachyspira. A number of mechanisms were identified, however future studies are required to explore these mechanisms in a more relevant in vivo chicken model

Impact of dietary organic acids and botanicals on intestinal integrity and inflammation in weaned pigs

Background: Organic acids, such as citric and sorbic acid, and pure plant-derived constituents, like monoterpens and aldehydes, have a long history of use in pig feeding as alternatives to antibiotic growth promoters. However, their effects on the intestinal barrier function and inflammation have never been investigated. Therefore, aim of this study was to assess the impact of a microencapsulated mixture of citric acid and sorbic acid (OA) and pure botanicals, namely thymol and vanillin, (PB) on the intestinal integrity and functionality of weaned pigs and in vitro on Caco-2 cells. In the first study 20 piglets were divided in 2 groups and received either a basal diet or the basal diet supplemented with OA + PB (5 g/kg) for 2 weeks post-weaning at the end of which ileum and jejunum samples were collected for Ussing chambers analysis of trans-epithelial electrical resistance (TER), intermittent short-circuit current (I SC ), and dextran flux. Scrapings of ileum mucosa were also collected for cytokine analysis (n = 6). In the second study we measured the effect of these compounds directly on TER and permeability of Caco-2 monolayers treated with either 0.2 or 1 g/l of OA + PB. Results: Pigs fed with OA + PB tended to have reduced I SC in the ileum (P = 0.07) and the ileal gene expression of IL-12, TGF-\u3b2, and IL-6 was down regulated. In the in vitro study on Caco-2 cells, TER was increased by the supplementation of 0.2 g/l at 4, 6, and 14 days of the experiment, whereas 1 g/l increased TER at 10 and 12 days of treatment (P < 0.05). Dextran flux was not significantly affected though a decrease was observed at 7 and 14 days (P = 0.10 and P = 0.09, respectively). Conclusions: Overall, considering the results from both experiments, OA + PB improved the maturation of the intestinal mucosa by modulating the local and systemic inflammatory pressure ultimately resulting in a less permeable intestine, and eventually improving the growth of piglets prematurely weaned