Marcela Maria Uhart

Phthalate acid esters (PAEs) are widely used plastic additives that have become ubiquitous contaminants in marine environments. Filter-feeding baleen whales may be exposed to these pollutants through water, prey or ingested plastic debris. While macroplastics have been reported in the gut of a southern right whale (SRW, Eubalaena australis ), exposure to PAEs has not been assessed. Here, we quantified three lipophilic PAEs, dimethyl phthalate (DMP), dibutyl phthalate (DBP), and di-2-ethylhexyl phthalate (DEHP), in the blubber of 13 SRWs (three calves, three juveniles and seven adults) stranded in 2021 at Península Valdés, Argentina. More than 90% of samples contained detectable PAE levels, and 46.2% were above quantification limits. DEHP and DBP were the most prevalent compounds (61.5% and 30.8%, respectively), although the biological significance of the detected concentrations remains uncertain. This is the first report of PAEs in SRW blubber and suggests potential mother-calf transfer, highlighting exposure of Southern Hemisphere mysticetes to plastic-derived chemicals.

We present a summary of the initial findings regarding the foraging patterns of southern elephant seals (Mirounga leonina) departing from the small, nascent colony of Jackson Bay, Tierra del Fuego, Chile. Eight juvenile males were satellite tracked while foraging at sea; four of them yielded complete tracks of their trips. The study highlights the importance of both the inland waters in the Chilean fjords and the pelagic waters off the coast deeper than 200 m as preferred foraging areas. Southern elephant seals utilizing the fjords also undertook extensive excursions into the SE Pacific, up to 600 km offshore. In open waters, the study animals engaged in extended loops lasting up to 30 days and covering 2,580 km of horizontal travel, characterized by few focal areas of activity. A comparison with individuals from the Península Valdés colony in Argentina underscores connectivity between colonies and identifies the Strait of Magellan and the Drake Passage as important corridors for southern elephant seal foraging migrations. Overall, high individual variability precludes identifying a dominant strategy for the Jackson Bay southern elephant seals, at least during this early stage of recolonization of the species’ historical range.

Climate change is expected to significantly alter the ecological dynamics of zoonotic diseases, yet its long-term impact on rodent-borne hemorrhagic fevers in South America remains poorly understood. Here, we developed a robust predictive modeling framework that integrates species distribution models with a mechanistic force-of-infection approach to evaluate the effects of climate change on zoonotic risk of New World Arenaviruses. Using climate projections under Shared Socioeconomic Pathways SSP2-4.5 (moderate) and SSP5-8.5 (severe), our models predict a substantial increase in spillover risk across endemic and non-endemic regions over the next two decades. Projected increases in spillover risk for Guanarito, Machupo, and Junin viruses are primarily driven by climate-induced shifts in temperature seasonality, reduced precipitation, and expanding anthropogenic land use, particularly cropland and urban areas within reservoir habitats. Our projections identify transboundary arenaviral hotspots, underscoring the urgent need for coordinated climate-adaptive public health policies, including cross-border surveillance efforts, land-use planning, and resilient rural health systems.

Per- and polyfluoroalkyl substances (PFAS) are globally distributed anthropogenic contaminants of concern due to their environmental persistence, bioaccumulation potential, and adverse health effects. Despite increasing recognition of PFAS exposure in marine wildlife, data for penguins remain limited, in part due to challenges associated with traditional sampling methods. We present a proof-of-concept application of silicone passive samplers (SPS) as a minimally invasive approach to characterize contact-based environmental PFAS exposure in penguins. SPS bands (n = 55) were deployed (2–9 days) on Magellanic penguins (Spheniscus magellanicus) at two colonies along the Patagonian coast of Argentina across three consecutive breeding seasons. Forty PFAS were targeted and quantified using liquid chromatography-tandem mass spectrometry (LC-MS/MS). PFAS were detected on the vast majority (90.7%) of SPS bands, with a mean PFAS concentration of 2.26 ± 2.46 ng/g (maximum = 16.23 ng/g). Five legacy (PFPeA, PFHxA, PFHxS, PFHpA, and PFOS) and four emerging compounds (HFPO-DA, 6:2 FTS, NMeFOSAA, and NEtFOSAA) were identified. The frequency and/or concentration of PFPeA, PFHxA, PFHpA, HFPO-DA, and 6:2 FTS varied significantly among colony-season cohorts, while PFHxA, 6:2 FTS, and NMeFOSAA varied significantly with the duration of the deployment period. SPS bands provide a minimally invasive, repeatable, and practical approach for comparing relative external exposure profiles of penguins, and they could be adapted for other sensitive species to improve our understanding of PFAS and contaminant exposure in wildlife. Future studies should pair SPS deployments with biological matrices (e.g., blood) to determine how SPS-derived profiles relate to internal biological burdens and to validate the interpretation of SPS measurements.

Summary: High pathogenicity avian influenza virus (HPAIV) H5N1 reached the sub-Antarctic and Antarctica in 2023, subsequently spreading to remote locations within this region where it had devastating impacts on seal, penguin and albatross populations. The threat to marine wildlife over this broad area exemplifies the need to understand H5N1 long-distance dispersal and evolution. We obtained 104 novel viral genomic sequences from samples that we collected at South Georgia, Kerguelen, Crozet, Prince Edward, Falklands/Malvinas Islands and the Antarctic Peninsula in a region spanning 8,000 kilometers. Using recent phylogeographic modeling advances we show that H5N1 spread encompassed numerous transmission events between distant locations, accumulating mammalian-adaptive mutations in the process. Seals are the most affected species, but we reveal that the long-distance eastward virus dispersal better aligns with the long-distance movements of large petrels and albatrosses. The risk of H5N1 endemisation, dispersal to other locations and ongoing evolution are highly concerning.

The hepatitis E virus (HEV) is an emerging multi-host pathogen, with suids being the main reservoir. Humans are primarily infected through the consumption of contaminated water or food. In Argentina, HEV circulation has been confirmed in humans, domestic pigs, wild boar (Sus scrofa), and surface water. In El Palmar National Park, invasive wild boar and axis deer (Axis axis) are controlled, and their meat is released for public consumption, with trimmings and offal frequently fed to dogs. Between 2017 and 2019, we conducted a multi-species serological survey in this protected area to assess HEV exposure in invasive mammals and in dog and human consumers of game meat. We also evaluated associations between seropositivity and environmental variables, as well as behavioral risk factors among game-meat consumers. Total anti-HEV antibodies were detected in 29/75 (38.67%) wild boar, 1/134 (0.75%) deer, 1/18 (5.6%) dogs, and 6/59 (10.17%) humans. A spatial cluster of seropositive wild boar was identified in a low-lying, flood-prone area near the confluence of the El Palmar stream and the Uruguay river, suggesting increased risk of environmental transmission. This is the first report of HEV exposure in wild boar from this park and in axis deer and dogs in Argentina. Participation in culling and game meat handling and consumption may contribute to HEV exposure pathways among humans. These findings improve understanding of HEV epidemiology at the wildlife–domestic animal–human interface and highlight the influence of environmental factors and human behavior on zoonotic virus circulation.