Swine Backyard Production Systems in Central Chile: Characterizing Farm Structure, Animal Management, and Production Value Chain.

Backyard production systems (BPS) are highly distributed in central Chile. While poultry BPS have been extensively characterized, there remains a notable gap in the characterization of swine BPS in central Chile. In addition, there is evidence that zoonotic pathogens, such as influenza A virus and Salmonella spp., are circulating in backyard poultry and pigs. A total of 358 BPS located in central Chile were evaluated between 2013 and 2015 by interviewing farm owners. Severe deficiencies in biosecurity measures were observed. The value chain of swine backyard production identified food, veterinary care (visits and products), and replacement or breeding animals as the primary inputs to the backyard. The most common origin of swine replacements was from outside the BPS (63%). The main outputs of the system were identified as meat and live animals, including piglets and breeding animals. In 16% of BPS, breeding animals were lent to other BPS, indicating the existence of animals and animal product movement in and out of backyard farms. Results from this study indicate that swine BPS in central Chile represents an animal-human interface that demands special attention for implementing targeted preventive measures to prevent the introduction and spread of animal pathogens and the emergence of zoonotic pathogens.

Evidence of influenza infection in dogs and cats in central Chile.

As companion animals, dogs and cats live in close contact with humans, generating the possibility of interspecies pathogen transmission events. Equine origin H3N8 and avian origin H5N1 influenza virus have been reported in dogs and cats respectively since 2004 with outbreaks associated with different strains recorded for both species in Asia and North America. To date, there have been no reports of influenza viruses from companion animals in South America. To fill this gap in knowledge, we performed active epidemiological surveillance in shelters that received abandoned animals, backyard production systems and veterinary clinics between May 2017 and January 2019 to estimate the burden of influenza infection in cats and dogs in the central region of Chile. Blood samples, oropharyngeal swabs or both were collected for influenza A virus detection by RT-qPCR, NP-ELISA, and hemagglutination inhibition assay. Logistic regression models were performed to assess the association between NP-ELISA-positivity and variables including sex and animal origin. The percentage of ELISA-positive samples was 43.5 % (95 % CI: 37.0-50.1) and 23.3 % (95 % CI: 10.6-42.7) for dogs and cats, respectively. No association was found between NP-ELISA results and sex or animal origin for either dogs or cats. Two ELISA positive samples showed hemagglutination inhibition titers against pandemic H1N1 influenza. One dog sample tested positive by RT-qPCR, indicating an overall RT-qPCR positivity in dogs of 1.1 % (95 % CI: 0.05-6.7). None of the tested cat samples were positive by this assay.

Habitat-islands in the coastal Atacama Desert: loss of functional redundancy, but not of functional diversity, with decreased precipitation.

BACKGROUND AND AIMS: Aridity is increasing in many regions of the world, but microclimatic conditions may buffer plant communities from the direct effects of decreased precipitation, creating habitat islands. However, reduced precipitation can also impact these communities indirectly by decreasing the suitability of the surrounding habitat, thus limiting incoming propagules and increasing the chances of population decline and species loss. We test whether decreased precipitation results in loss of species and functional diversity within habitat islands, evaluating in particular whether declines in species diversity and abundance are less likely to result in loss of functional diversity if species/individual loss is stochastic (i.e. independent of species/individual traits) and communities/populations are functionally redundant. METHODS: Lomas communities are discrete plant communities embedded in the Atacama Desert, maintained by the microclimatic conditions created by fog. We recorded species and functional diversity in six Lomas communities along a 500 km long precipitation gradient in northern Chile. Functional traits were measured in 20 individuals per species, in those species that accounted for approx. 75 % of the abundance at each site. We calculated functional diversity and functional redundancy of the community, and intraspecific functional variation. KEY RESULTS: Decreased precipitation was associated with lower species diversity and lower species abundances. However, no traits or functional strategies increased or decreased consistently with precipitation, suggesting stochastic species/individual loss. Species with stress-tolerant strategies were predominant in all sites. Although species diversity decreased with decreasing precipitation, functional diversity remained unchanged. Lower functional redundancy in the drier sites suggests that mainly functionally redundant species were lost. Likewise, intraspecific functional variation was similar among communities, despite the lower species abundance in drier sites. CONCLUSIONS: Decreased precipitation can impact habitat island communities indirectly by decreasing the suitability of the surrounding habitat. Our results support the idea that a stochastic loss of species/individuals from functionally redundant communities and populations does not result in loss of functional diversity.

Temporal dynamics and the influence of environmental variables on the prevalence of avian influenza virus in main wetlands in central Chile.

Although wild birds are considered the main reservoir of the influenza A virus (IAV) in nature, empirical investigations exploring the interaction between the IAV prevalence in these populations and environmental drivers remain scarce. Chile has a coastline of more than 4000 kilometres with hundreds of wetlands, which are important habitats for both resident and inter-hemispheric migratory species. The aim of this study was to characterize the temporal dynamics of IAV in main wetlands in central Chile and to assess the influence of environmental variables on AIV prevalence. For that purpose, four wetlands were studied from September 2015 to June 2018. Fresh faecal samples of wild birds were collected for IAV detection by real-time RT-PCR. Furthermore, a count of wild birds present at the site was performed and environmental variables, such as temperature, rainfall, vegetation coverage (Normalized Difference Vegetation Index (NDVI)) and water body size, were determined. A generalized linear mixed model was built to assess the association between IAV prevalence and explanatory variables. An overall prevalence of 4.28% ± 0.28% was detected with important fluctuations among seasons, being greater during summer (OR = 4.87, 95% CI 2.11 to 11.21) and fall (OR = 2.59, 95% CI 1.12 to 5.97). Prevalence was positively associated with minimum temperature for the month of sampling and negatively associated with water body size measured two months before sampling, and NDVI measured three months before sampling. These results contribute to the understanding of IAV ecological drivers in Chilean wetlands providing important considerations for the global surveillance of IAV.

Movement Restriction and Increased Surveillance as Efficient Measures to Control the Spread of Highly Pathogenic Avian Influenza in Backyard Productive Systems in Central Chile.

During the last 5 years there has been an alarming number of reports of highly pathogenic avian influenza worldwide. However, little is known about the status of this disease in South America. Chile has been the only country in South America where an HPAI outbreak was reported. This outbreak occurred in 2002 and was due to an H7N3 HPAI, where the most plausible hypothesis that explained the entrance of the disease to the country, had relation to migratory wild birds. Commercial poultry farms in Chile are highly integrated and have high biosecurity standards. Nevertheless, poultry backyard production systems lack biosecurity measures and are widely distributed. Since 2002 outbreak, avian influenza viruses have been identified in wild birds and different animal species kept in backyard productive systems (BPS) in Chile. The aim of this study was to simulate the possible natural history of HPAI after its introduction to BPS in central Chile and to simulate different intervention strategies. To do so, the North American Animal Disease Spread Model version 3.3 was used. The results showed that a median of 15,930 BPS would be affected if HPAI spread among BPS in central Chile, representing 97.8% of the current amount of BPS existing in study zone. Movement restrictions, pre-emptive destruction, passive surveillance, tracing of infected premises and combinations of the three, where the intervention strategies tested in the simulation model. From all the interventions simulated, movement restrictions together with increasing surveillance (through increasing passive surveillance and good tracing of infected premises) had the biggest effect, reducing the median number of infected BPS in 90.8%. However, more studies are needed to more accurately estimate local contact rates. These results can guide the official veterinary services to consider potential mechanisms to control or prevent an HPAI emergency situation.

Factores ambientales relacionados con la presentación de virus influenza A en aves silvestres / Environmental factors related to Influenza A virus occurrence in wild birds

RESUMEN La investigación y el interés por el virus influenza aviar han aumentado considerablemente en las últimas décadas en respuesta a los brotes de influenza aviar de alta patogenicidad en aves de corral y a su potencial zoonótico. Las aves silvestres acuáticas son el principal reservorio del virus en la naturaleza, por lo tanto, la comprensión de la dinámica de infección del virus influenza A (VIA) en estas poblaciones es fundamental para entender su potencial de persistencia en el ambiente y sus posibilidades de transmisión hacia aves domésticas y humanos. Se ha identificado que factores ambientales (como temperatura, precipitaciones, vegetación y características del paisaje, entre otros) pueden tener un importante rol en el mantenimiento y diseminación del virus en las zonas de concentración de aves silvestres. Sin embargo, los estudios que incluyen aspectos ecológicos del virus y que exploran la interacción entre la prevalencia del VIA en aves silvestres y el ambiente, continúan siendo escasos. En esta revisión se resumen los esfuerzos de investigación que se han realizado para identificar a los factores ambientales involucrados en la persistencia y transmisión del VIA en lugares de concentración de aves silvestres y cómo estos factores pueden incidir en la prevalencia del virus en estas poblaciones, generando diferencias en la presentación de la infección entre distintas zonas geográficas.

ABSTRACT Research and interest in avian influenza virus have increased considerably in recent decades in response to highly pathogenic avian influenza outbreaks in poultry and its zoonotic potential. Wild waterfowl are the main reservoir of the virus, therefore studying the dynamics of influenza A virus (IAV) infection in these populations is essential in order to understand its potential persistence in the environment and transmission to poultry and humans. It has been identified that environmental factors (such as temperature, rainfall, vegetation and landscape characteristics, among others) can play an important role in the maintenance and dissemination of the virus in the areas of concentration of wild birds. However, studies that include ecological aspects of the virus and explore the interaction between the prevalence of IAV in wild birds and environmental factors remain scarce. This review summarizes research efforts that have been made to identify the environmental factors involved in the persistence and transmission of IAV in areas of wild bird concentration and how these factors may influence the prevalence of the virus in these populations, generating differences in the presentation of the infection among different geographical areas.

Registro de un Monstruo Diprósopo de Tiburón Azul (Prionace glauca) en Chile / Record of a Diprosopus Monster of Blue Shark (Prionace glauca) from Chile

Un espécimen de siameses de tiburón azul, Prionace glauca, fue recolectado durante actividades de pesca en el norte de Chile. Según una clasificación basada en el grado de duplicación y el sitio de fusión de los gemelos, el espécimen corresponde a un monstruo del tipo diprósopo tetroftalmo. El individuo tiene una duplicación craneofacial parcial con presencia de cuatro globos oculares e igual número de narinas. Las cavidades orales están interconectadas convergiendo en una única faringe. El tronco es simple; la columna presenta lordosis torácica y una torsión helicoidal en su porción caudal. Este es el primer reporte de siameses en condrictios chilenos y primer registro mundial de diprosopa en tiburones.

A conjoined twins specimen of blue shark Prionace glauca was collected during fishing activities in Northern Chile. According to a classification based on duplication degree and fusion site of the twins, it represents a monster of diprosopus tetrophthalmus type. The specimen has a partial craniofacial duplication with presence of four eyeballs and an equal number of nostrils. Oral cavities are interconnected, converging in a single pharynx. The trunk is simple; the vertebral column presents thoracic lordosis and helical torsion in its caudal portion. This is the first Chilean record of conjoined twins to chondrichthyan and first world record of diprosopia in sharks.