No abstract

No abstract

BackgroundHantavirus pulmonary syndrome (HPS) is an infection endemic in Chile and Argentina, caused by Andes hantavirus (ANDV). The rodent Oligoryzomys longicaudatus is suggested as the main reservoir, although several other species of Sigmodontinae are known hosts of ANDV. Here, we explore potential ANDV transmission risk to humans in southern South America, based on eco-epidemiological associations among: six rodent host species, seropositive rodents, and human HPS cases.MethodsWe used ecological niche modeling and macroecological approaches to determine potential geographic distributions and assess environmental similarity among rodents and human HPS cases.ResultsHighest numbers of rodent species (five) were in Chile between 35° and 41°S latitude. Background similarity tests showed niche similarity in 14 of the 56 possible comparisons: similarity between human HPS cases and the background of all species and seropositive rodents was supported (except for Abrothrix sanborni). Of interest among the results is the likely role of O. longicaudatus, Loxodontomys micropus, Abrothrix olivaceus, and Abrothrix longipilis in HPS transmission to humans.ConclusionsOur results support a role of rodent species’ distributions as a risk factor for human HPS at coarse scales, and suggest that the role of the main reservoir (O. longicaudatus) may be supported by the broader rodent host community in some areas.Electronic supplementary materialThe online version of this article (10.1186/s12942-018-0142-z) contains supplementary material, which is available to authorized users.

No abstract

Aim The distribution and genetic composition of marine populations is the result of climatic and oceanographic factors as well as life history strategies. Studying species with wide distributions and high dispersal potential in sites that were differentially affected during the Pleistocene glaciations provides an opportunity to evaluate the genetic and distributional effect of glaciations on marine populations, such as the limpet Siphonaria lesonii. The aim of the present study is to evaluate the differential effects of glaciations on areas covered and not covered by ice sheets during the Pleistocene glaciations. Location Intertidal zone of the south‐eastern Pacific covering approximately 5,000 km of coastline of Peru and Chile. Methods We performed molecular analyses of mitochondrial and nuclear data jointly, as well as environmental niche modelling (ENM) of populations of the limpet Siphonaria lessonii. Using ENM, we modelled the potential distributional range of the species in the present and its distribution during the Last Glacial Maximum (LGM). Results Two lineages were found that were separated by a break at 41° S, corresponding to the biogeographical discontinuity previously reported for this region. Both of these lineages experienced genetic and demographical fluctuations that match the Pleistocene glaciations; however, the variability was more intense in the southern lineage. Phylogeography and ENM yielded complementary results for the southern lineage, which experienced loss of genetic diversity and habitat during the LGM, whereas the northern lineage evidenced loss of genetic diversity without distributional changes. Main conclusions The phylogeographical and ENM approaches suggest a historical scenario involving demographic and distributional contractions of S. lessonii surviving in glacial refugia in the southern portion of the south‐eastern Pacific. This study is the first to include both phylogeographical and ENM analyses of marine species from the Southern Hemisphere.

Cetacean strandings (CS) have been reported in increasing numbers in coastal areas worldwide. Although the causes of these strandings are unknown, a number of anthropogenic and environmental factors have been suggested. This paper aims to characterize CS patterns and describe their finescale spatiotemporal dynamics. We analysed spatial and spatiotemporal CS patterns in Chile from January 1968 to January 2020. We identified a total of 436 CS events affecting eight cetacean families, 21 genera, and 35 species, which represent more than 85% of the reported species richness for the country. Most CS events (94.1%) were single (i.e., ≤two individuals). There were also 18 mass stranding (three to 24 individuals, 4.1%) and nine unusually large mass stranding events (>25 individuals, 2%). Purely spatial tests showed CS events appearing in random occurrence along the Chilean coast. Local tests for spatio-temporal clusters, however, identified a greater number of hotspots reported in the southernmost part of the country, namely, Chilean Patagonia. Specifically, significant spatio-temporal clusters were identified and defined as containing three or more individuals within a two-month period as a focal coastal event (<1 km radius). It is a cause of concern that CS events in Chile have been increasing consistently over the last decades, and although we were not able to identify their causes, we are able to highlight the importance of changes in climate conditions and of an increase in monitoring activities as primary drivers for such patterns, particularly important in Chilean Patagonia. Marine mammals are prime sentinel species for ecosystems and human health alike 1. Many of them have long life spans, are long-term coastal residents, feed at a high trophic level, and have unique fat stores that can serve as depots for anthropogenic toxins 1. Consequently, the study of stranded marine mammals provides valuable records of circulating pathogens and contaminants that could be a risk for coastal populations and provide important information in regard to marine mammals' biodiversity in coastal areas worldwide 2-4. Likewise, stranding records and associated attributes 5 can provide vital information on species richness and diversity by identifying spatial locations and periods of occurrence 6 , and they can also provide a very effective early warning system for the protection of human health 1. Cetacean strandings (CS) constitute a worldwide phenomenon, yet the cause of these events remains largely unknown 7. Although few primary causes have been proposed, there is a general agreement that CS are multifactorial in nature and species dependent 6. For instance, proposed causes include navigational errors from bathymetric features, coastal configuration; or geomagnetic topography 8,9 ; climate or oceanographic events 10,11 ; anthropogenic noise and sonar interference 12,13 ; pollution 14,15 ; infectious diseases 16-18 , and behavioural patterns 19 .

No abstract

Viral haemorrhagic septicaemia virus (VHSV) genotype IVb has been responsible for large-scale fish mortality events in the Great Lakes of North America. Anticipating the areas of potential VHSV occurrence is key to designing epidemiological surveillance and disease prevention strategies in the Great Lakes basin. We explored the environmental features that could shape the distribution of VHSV, based on remote sensing and climate data via ecological niche modelling. Variables included temperature measured during the day and night, precipitation, vegetation, bathymetry, solar radiation and topographic wetness. VHSV occurrences were obtained from available reports of virus confirmation in laboratory facilities. We fit a Maxent model using VHSV-IVb reports and environmental variables under different parameterizations to identify the best model to determine potential VHSV occurrence based on environmental suitability. VHSV reports were generated from both passive and active surveillance. VHSV occurrences were most abundant near shore sites. We were, however, able to capture the environmental signature of VHSV based on the environmental variables employed in our model, allowing us to identify patterns of VHSV potential occurrence. Our findings suggest that VHSV is not at an ecological equilibrium and more areas could be affected, including areas not in close geographic proximity to past VHSV reports.