Emerging and endemic zoonotic diseases: surveillance and diagnostics.

In this paper, the authors: (a) list methods used to diagnose zoonotic diseases in humans and animals; (b) identify between-species differences in diagnostic approaches, providing commentary on the benefits that might arise from simultaneous interpretation of data from human and animal health surveillance systems; and (c) reiterate the importance of using species-specific, validated diagnostic tests for surveillance and disease outbreak investigations. Emerging and endemic zoonotic diseases are likely to provide a continued threat to global health in the short- to medium-term future. A good deal of knowledge about the drivers of infectious disease emergence has been developed based on numerous examples from the recent past. Sharing of diagnostic resources across human and animal health sectors, sharing of human and animal health surveillance data, development of skills in the interpretation of that data and awareness of issues related to the validation and interpretation of diagnostic test data are necessary prerequisites for an effective endemic disease surveillance system. A good understanding of the epidemiological patterns of endemic disease will allow human and animal health professionals be able to more quickly detect the presence of emerging disease threats.

Après avoir répertorié les méthodes utilisées pour diagnostiquer les maladies zoonotiques chez l'homme comme chez les animaux, les auteurs définissent les différentes approches diagnostiques suivant les espèces considérées et commentent les avantages qui pourraient découler d'une interprétation simultanée des données par les systèmes de surveillance en santé animale et en santé publique ; il réitèrent ensuite l'importance de recourir à des tests diagnostiques validés et spécifiques de l'espèce considérée dans le cadre de la surveillance et des enquêtes suite à l'apparition d'un foyer. Les maladies zoonotiques émergentes et endémiques représentent potentiellement une menace continue pour la santé mondiale à court et à moyen terme. Les facteurs favorisant l'émergence des maladies infectieuses sont désormais beaucoup mieux connus grâce aux enseignements tirés de nombreux exemples récents. Le partage des ressources diagnostiques entre les secteurs de la santé humaine et animale, les échanges des données de la surveillance sanitaire réunies par les deux secteurs, le renforcement des compétences en matière d'interprétation des données et la sensibilisation aux problématiques de la validation et de l'interprétation des données générées par les tests de diagnostic sont des conditions préalables à la mise en place d'un système efficace de surveillance des maladies endémiques. Une bonne compréhension des profils épidémiologiques des maladies endémiques permettra aux professionnels de la santé humaine et animale de détecter plus rapidement la présence de menaces émergentes.

Los autores proceden aquí a: a) relacionar los métodos empleados para diagnosticar enfermedades zoonóticas en personas y animales; b) señalar las diferencias que existen entre los distintos planteamientos de diagnóstico según la especie de que se trate, comentando asimismo las ventajas que podrían derivarse de la interpretación simultánea de los datos de los sistemas de vigilancia sanitaria y de los de vigilancia zoosanitaria; y c) reiterar la importancia que reviste el uso de pruebas de diagnóstico no solo validadas, sino también adaptadas específicamente a cada especie, para las labores de vigilancia y estudio de brotes. Lo más probable es que a corto y medio plazo las enfermedades zoonóticas, ya sean emergentes o endémicas, sigan constituyendo una amenaza para la salud mundial. Gracias a numerosos ejemplos del pasado reciente se ha ido constituyendo un buen conocimiento de los factores que propician la aparición de enfermedades infecciosas. Para disponer de un eficaz sistema de vigilancia de enfermedades endémicas hay una serie de requisitos previos indispensables: utilización compartida de los recursos de diagnóstico entre los sectores de la salud humana y la sanidad animal; intercambio de los datos de vigilancia sanitaria y de vigilancia zoosanitaria; adquisición de competencias para interpretar esos datos; y buen conocimiento de las cuestiones ligadas a la validación de pruebas de diagnóstico y a la interpretación de los datos que arrojan. Si los profesionales de la salud humana y la sanidad animal conocen debidamente los patrones epidemiológicos de las enfermedades endémicas, estarán en condiciones de detectar con más celeridad la presencia de enfermedades emergentes que constituyan una amenaza.

A transmissible cancer shifts from emergence to endemism in Tasmanian devils.

Emerging infectious diseases pose one of the greatest threats to human health and biodiversity. Phylodynamics is often used to infer epidemiological parameters essential for guiding intervention strategies for human viruses such as severe acute respiratory syndrome coronavirus 2 (SARS-Cov-2). Here, we applied phylodynamics to elucidate the epidemiological dynamics of Tasmanian devil facial tumor disease (DFTD), a fatal, transmissible cancer with a genome thousands of times larger than that of any virus. Despite prior predictions of devil extinction, transmission rates have declined precipitously from ~3.5 secondary infections per infected individual to ~1 at present. Thus, DFTD appears to be transitioning from emergence to endemism, lending hope for the continued survival of the endangered Tasmanian devil. More generally, our study demonstrates a new phylodynamic analytical framework that can be applied to virtually any pathogen.

Fasciola hepatica infection in cattle and the use of simulation models for endemic areas.

Fasciolosis is a food-borne disease that causes great distress to a range of hosts, including humans. The objectives of this study were to (1) evaluate the liver damage and carcass weight of cattle naturally infected with Fasciola hepatica from the state of Rio Grande do Sul (RS), Brazil, and to (2) determine the distribution of adult flukes in 12,236 cattle liver from RS. The data from these experiments were used to calculate the overall economic loss due to F. hepatica infection. Eighteen adult Polled Hereford cows were divided into a triclabendazole (TbG) and a F. hepatica-positive group (FhG). For Experiment 1, a generalized linear mixed model revealed a statistical difference in carcass weight (49.8 kg) between TbG and FhG. The Monte Carlo analysis also revealed that the animals' weight differences were due to the disease. For Experiment 2, the prevalence of infected livers was above 16% (1904/12,236), mostly (20.1%) from the south-west region of RS. The Susceptible-infected-recovered (SIR) epidemic model revealed the evolution of the infection using a high infectivity and low recovery rate. Other distinctive scenarios that occur in RS were also established with different rates of infectivity. The economic assessment showed a potential loss of US$45 million to the beef cattle industry of RS, with an overall State cost of US$90.3 million. These novel findings reveal the importance of fasciolosis infection, which can cause a significant health condition and poor animal welfare.