One Health is an interdisciplinary collaboration that aims at mitigating risks to human health arising from microorganisms present in non-human animal species, which have the potential to be transmitted and cause disease in humans. Different degrees of scientific collaboration and sectoral integration are needed for different types of zoonotic diseases, depending on the health and associated economic gains that can be expected from a One Health approach. Indeed, mitigating zoonotic risks related to emerging diseases with pandemic potential is different from mitigating risks related to endemic zoonotic diseases like brucellosis. Likewise, management of brucellosis at the wildlife–livestock interface in wildlife conservation areas is in essence different from mitigating transmission of a given Brucella species within its preferential host species, which in turn is different from mitigating the spillover of a given Brucella species to non-preferential host species, humans included. Brucellosis economic models often oversimplify and/or wrongly assess transmission between reservoir hosts and spillover hosts. Moreover, they may not properly value non-market outcomes, such as avoidance of human disease, consumer confidence and conservation biology issues. As a result, uncertainty is such that the economic predictions of these models can be questionable. Therefore, understanding the infection biology of Brucella species is a prerequisite. This paper reviews and highlights important features of the infection biology of Brucella species and the changing epidemiology of brucellosis that need to be integrated into a true One Health perspective of brucellosis. La noción de «Una sola salud» presupone una labor de colaboración interdisciplinar destinada a reducir los riesgos para la salud humana que plantean microorganismos presentes en especies animales capaces de transmitirse al hombre y causarle enfermedades. Para diferentes tipos de enfermedades zoonóticas se necesitan distintos grados de colaboración científica e integración sectorial, dependiendo de los beneficios sanitarios (y beneficios económicos conexos) que quepa esperar de los planteamientos de «Una sola salud». En efecto, no es lo mismo reducir el riesgo zoonótico derivado de enfermedades emergentes potencialmente pandémicas que mitigar riesgos ligados a enfermedades zoonóticas endémicas como la brucelosis. Análogamente, combatir la brucelosis en la interfaz entre animales salvajes y ganado doméstico en zonas de fauna salvaje protegida tiene poco que ver, en esencia, con reducir la transmisión de una especie de Brucella dentro de su especie hospedadora preferente, lo que a su vez tampoco es lo mismo que contener la extensión de una especie de Brucella a anfitriones no preferentes, en particular el ser humano. Los modelos económicos de la brucelosis suelen simplificar en exceso y/o evaluar erróneamente la transmisión de brucelas de anfitriones que ejercen de reservorio a anfitriones no preferentes, que constituyen así un vector de extensión. Además, a veces no cifran correctamente los resultados que carecen de valor de mercado, como el hecho de evitar contagios humanos, la confianza del consumidor o aspectos ligados a la biología de la conservación. Como consecuencia, existe tal nivel de incertidumbre que es posible cuestionar las predicciones económicas de dichos modelos. Por todo ello, entender la biología de la infección de las especies de Brucella es un requisito previo indispensable. Los autores examinan y destacan una serie de importantes características de la biología infectiva de las brucelas y de su cambiante epidemiología que deben ser integradas en una respuesta a la brucelosis que se base realmente en los postulados de «Una sola salud». « Une seule santé » se réfère à une collaboration pluridisciplinaire visant à atténuer les risques pour la santé publique imputables aux micro-organismes présents chez les animaux et transmissibles à l’homme. La collaboration scientifique et l’intégration sectorielle requises pour chaque type de maladie zoonotique varient en fonction de l’amélioration sanitaire attendue de la démarche « Une seule santé » et des bénéfices économiques qui peuvent en résulter. En effet, ce n’est pas du tout la même chose d’atténuer les risques zoonotiques liés à des maladies émergentes à potentiel pandémique et d’atténuer les risques liés à une maladie zoonotique endémique comme la brucellose. De même, les opérations de gestion de la brucellose à l’interface entre les animaux sauvages et le bétail dans les zones de protection de la faune sauvage sont par essence différentes des mesures d’atténuation du risque de transmission d’une espèce donnée de Brucella au sein de ses espèces hôtes préférentielles, mesures elles-mêmes différentes de celles visant à atténuer le risque de passage d’une espèce donnée de Brucella à des espèces d’hôtes incidents, parmi lesquelles l’espèce humaine. Les modèles économiques de la brucellose ont tendance à simplifier à outrance, voire à surévaluer ou sous-évaluer la transmission entre les hôtes réservoirs et les hôtes incidents. En outre, les répercussions autres que celles liées aux marchés ne sont pas toujours correctement évaluées ; c’est le cas d’aspects tels que l’évitement de la maladie chez l’homme, la confiance des consommateurs et la biologie de la...

Marine mammal Brucella spp. have been isolated from pinnipeds (B. pinnipedialis) and cetaceans (B. ceti) from around the world. Although the zoonotic potential of marine mammal brucellae is largely unknown, reports of human disease exist. There are few studies of the mechanisms of bacterial intracellular invasion and multiplication involving the marine mammal Brucella spp. We examined the infective capacity of two genetically different B. pinnipedialis strains (reference strain; NTCT 12890 and a hooded seal isolate; B17) by measuring the ability of the bacteria to enter and replicate in cultured phagocytes and epithelial cells. Human macrophage-like cells (THP-1), two murine macrophage cell lines (RAW264.7 and J774A.1), and a human malignant epithelial cell line (HeLa S3) were challenged with bacteria in a gentamicin protection assay. Our results show that B. pinnipedialis is internalized, but is then gradually eliminated during the next 72 – 96 hours. Confocal microscopy revealed that intracellular B. pinnipedialis hooded seal strain colocalized with lysosomal compartments at 1.5 and 24 hours after infection. Intracellular presence of B. pinnipedialis hooded seal strain was verified by transmission electron microscopy. By using a cholesterol-scavenging lipid inhibitor, entrance of B. pinnipedialis hooded seal strain in human macrophages was significantly reduced by 65.8 % (± 17.3), suggesting involvement of lipid-rafts in intracellular entry. Murine macrophages invaded by B. pinnipedialis do not release nitric oxide (NO) and intracellular bacterial presence does not induce cell death. In summary, B. pinnipedialis hooded seal strain can enter human and murine macrophages, as well as human epithelial cells. Intracellular entry of B. pinnipedialis hooded seal strain involves, but seems not to be limited to, lipid-rafts in human macrophages. Brucella pinnipedialis does not multiply or survive for prolonged periods intracellulary.

A species-independent indirect enzyme-linked immunosorbent assay (iELISA) based on chimeric protein A/G was established for the detection of anti- Brucella antibodies in Arctic wildlife species and compared to previously established brucellosis serological tests for hooded seals ( Cystophora cristata ), minke whales ( Balaenoptera acutorostrata ), sei whales ( Balaenoptera borealis ), fin whales ( Balaenoptera physalus ), and polar bears ( Ursus maritimus ), as well as bacteriology results for reindeer and caribou ( Rangifer tarandus sp.). The protein A/G iELISA results were consistent with the other serological tests with Cohen kappa values between 0.47 and 0.92, and the protein A/G iELISA can thus offer a technically simple method for these species yielding results consistent with established brucellosis serological tests. Receiver operator characteristics analysis proved that the reindeer and caribou protein A/G iELISA results were consistent with the bacteriological gold standard with an area under the curve of 0.99, and the protein A/G iELISA was thus validated as a sensitive and specific serological method for the detection of anti- Brucella antibodies in reindeer and caribou. The binding of the antibodies from the respective species to protein A and G were also evaluated in the iELISA. The antibodies from hooded seals and polar bears reacted stronger to protein A than to G. The sei whale, fin whale, reindeer, and caribou antibodies reacted stronger to protein G than to A. The minke whale antibodies reacted to both protein A and G. There was a strong correlation ( r _s = 0.88–0.98) between the optical density results obtained with the iELISA with protein A/G and protein A or G, showing that protein A/G is as well suited as protein A or G for the detection of anti- Brucella antibodies in these species with the iELISA.

The environmental temperature has profound effects on biological systems of marine aquatic organisms and plays a critical role in species distribution and abundance. Particularly during the warmer seasons, variations in habitat temperature may introduce episodes of stressful temperatures which the organisms must adapt to and compensate for to maintain physiological homeostasis. The marine environment is changing and predicted raises in water temperatures will affect numerous marine species. Translocation of pathogens follow migration of species and alternations in physical environmental parameters may have influence upon the virulence of pathogens, as well as the hosts immune responses. While pathogenicity of many true pathogens is expected to increase following climate induced temperature stress, the impact from environmental stressors on the occurrence and severity of opportunistic infections is unknown. Here we describe how thermal stress in the cold-water species Atlantic cod influenced the fish immune responses against an opportunistic intracellular bacterium. Following experimental infection with Brucella pinnipedialis at normal water temperature (6°C) and sub-optimal temperature (15°C), cod cleared the intracellular bacteria more rapidly at the highest temperature. The overall immune response was faster and of higher amplitude at 15°C, however, a significant number of cod died at this temperature despite efficient clearance of infection. An increased growth rate not affected by infection was observed at 15°C, confirming multiple energy demanding processes taking place. Serum chemistry suggested that general homeostasis was influenced by both infection and increased water temperature, highlighting the cumulative stress responses (allostatic load) generated by simultaneous stressors. Our results suggest a trade-off between resistance and tolerance to survive infection at sub-optimal temperatures and raise questions concerning the impact of increased water temperatures on the energetic costs of immune system activation in aquatic ectotherms.

A high prevalence of Brucella pinnipedialis serology and bacteriology positive animals has been found in the Northeast Atlantic stock of hooded seal ( Cystophora cristata); however no associated gross pathological changes have been identified. Marine mammal brucellae have previously displayed different infection patterns in human and murine macrophages. To investigate if marine mammal Brucella spp. are able to invade and multiply in cells originating from a presumed host species, we infected alveolar macrophages from hooded seal with a B. pinnipedialis hooded seal isolate. Hooded seal alveolar macrophages were also challenged with B. pinnipedialis reference strain (NCTC 12890) from harbor seal ( Phoca vitulina), B. ceti reference strain (NCTC 12891) from harbor porpoise ( Phocoena phocoena) and a B. ceti Atlantic white-sided dolphin ( Lagenorhynchus acutus) isolate (M83/07/1), to evaluate possible species-specific differences. Brucella suis 1330 was included as a positive control. Alveolar macrophages were obtained by post mortem bronchoalveolar lavage of euthanized hooded seals. Phenotyping of cells in the lavage fluid was executed by flow cytometry using the surface markers CD14 and CD18. Cultured lavage cells were identified as alveolar macrophages based on morphology, expression of surface markers and phagocytic ability. Alveolar macrophages were challenged with Brucella spp. in a gentamicin protection assay. Following infection, cell lysates from different time points were plated and evaluated quantitatively for colony forming units. Intracellular presence of B. pinnipedialis hooded seal isolate was verified by immunocytochemistry. Our results show that the marine mammal brucellae were able to enter hooded seal alveolar macrophages; however, they did not multiply intracellularly and were eliminated within 48 hours, to the contrary of B. suis that showed the classical pattern of a pathogenic strain. In conclusion, none of the four marine mammal strains tested were able to establish a persistent infection in primary alveolar macrophages from hooded seal.

Background: Marine Brucella spp. have been isolated from numerous pinniped and cetacean species, but pathological findings in association with infection with Brucella pinnipedialis in pinnipeds have been sparse. The capacity of brucellae to survive and replicate within host macrophages underlies their important ability to produce chronic infections, but previous work has shown that B. pinnipedialis spp. are rapidly eliminated from hooded seal ( Cystophora cristata ) alveolar macrophages. Results: To investigate if multiplication could take place in other hooded seal cell types, primary epithelial cells were isolated, verified to express the epithelial marker cytokeratin and challenged with three different strains of B. pinnipedialis ; B. pinnipedialis sp. nov., B. pinnipedialis hooded seal strain B17, and B. pinnipedialis hooded seal strain 22F1. All strains were steadily eliminated and the amounts of intracellular bacteria were reduced to less than one-third by 48 h post infection. Intracellular presence was verified using immunocytochemistry. Conclusions: So far, intracellular multiplication in seal cells has not been documented for B. pinnipedialis . The lack of intracellular survival in macrophages, as well as in epithelial cells, together with the fact that pathological changes due to B. pinnipedialis infection is not yet identified in seals, suggests that the bacteria may only cause a mild, acute and transient infection. These findings also contribute to substantiate the hypothesis that seals may not be the primary host of B. pinnipedialis and that the transmission to seals are caused by other species in the marine environment.