Constanza Toro‐Valdivieso

Background: Ehlers-Danlos syndromes (EDS) are rare heritable connective tissue disorders, most commonly linked to collagen abnormalities. In dogs, reported cases are infrequent and typically involve skin fragility and joint laxity, with limited understanding of underlying genetic causes. This report describes an unusual, aggressive, and fatal case of an Ehlers–Danlos–like syndrome (EDlS) in a Maltese dog, with several uncommon features. Unlike most canine EDS cases, which show collagen defects, this case revealed minimal collagen alterations; instead, elastic fibers were primarily affected. Case report: A one-and-a-half-year-old male Maltese dog presented with progressive abdominal masses, skin fragility, joint deformities, and frequent bruising since early life. Clinical examination revealed hyperextensible, fragile skin, hematomas, and contractures of the hind limbs. Imaging confirmed a hernia lacking supportive connective structures. Histopathological analysis showed elastic fiber hypertrophy and fragmentation, with minimal collagen changes. Despite palliative wound management, the patient died within ten days of the initial consultation due to spontaneous evisceration and vascular rupture. Conclusion: The histological features are consistent with a possible Tenascin-X deficiency. Definitive molecular classification was beyond the scope of this case. This report expands the spectrum of EDlS in dogs.

This report presents the first case of nodular dermatofibrosis with renal cysts (NDRC) in a beagle. In this atypical case, the gene mutation associated with the disease was not present, the renal cysts showed dynamic changes in size and number, and the patient has greatly surpassed the NDRC life expectation.

Heavy metals, including mercury (Hg) and cadmium (Cd), occur naturally or anthropogenically and are considered toxic to the environment and human health. However, studies on heavy metal contamination focus on locations close to industrialized settlements, while isolated environments with little human activity are often ignored due to perceived low risk. This study reports heavy metal exposure in Juan Fernandez fur seals (JFFS), a marine mammal endemic to an isolated and relatively pristine archipelago off the coast of Chile. We found exceptionally high concentrations of Cd and Hg in JFFS faeces. Indeed, they are among the highest reported for any mammalian species. Following analysis of their prey, we concluded that diet is the most likely source of Cd contamination in JFFS. Furthermore, Cd appears to be absorbed and incorporated into JFFS bones. However, it was not associated with mineral changes observed in other species, suggesting Cd tolerance/adaptations in JFFS bones. The high levels of silicon found in JFFS bones may counteract the effects of Cd. These findings are relevant to biomedical research, food security and the treatment of heavy metal contamination. It also contributes to understanding the ecological role of JFFS and highlights the need for surveillance of apparently pristine environments.

As apex predators, pinnipeds are considered to be useful bioindicators of marine and coastal environments. Endemic to a small archipelago in the South Pacific, the Juan Fernandez fur seal (JFFS) is one of the less‐studied members of the pinniped family Otariidae. This study aimed to characterize the fecal microbiome of the JFFS for the first time, to establish a baseline for future studies of host–microbial–environment interactions and monitoring programs. During two consecutive reproductive seasons, 57 fecal samples were collected from seven different JFFS colonies within the Juan Fernandez Archipelago, Chile. Bacterial composition and abundance were characterized by sequencing the V4 region of the 16S rRNA gene. The overall microbiome composition was dominated by five phyla: Firmicutes (40% ±24), Fusobacteria (30% ±17), Bacteroidetes (22% ±10), Proteobacteria (6% ±4), and Actinobacteria (2% ±3). Alpha diversity was higher in Tierras Blancas. However, location was not found to be a dominant driver of microbial composition. Interestingly, the strongest signal in the data was a negative association between the genera Peptoclostridium and Fusobacterium, which explained 29.7% of the total microbial composition variability between samples. The genus Peptoclostridium has not been reported in other pinniped studies, and its role here is unclear, with interpretation challenging due to a lack of information regarding microbiome functionality in marine mammals. As a first insight into the JFFS fecal microbiome, these results contribute towards our understanding of the natural microbial diversity and composition in free‐ranging pinnipeds.

As apex predators, pinnipeds are considered to be useful bioindicators of marine and coastal environments. Endemic to a small archipelago in the South Pacific, the Juan Fernandez fur seal (JFFS) is one of the less-studied members of the pinniped family Otariidae. This study aimed to characterise the faecal microbiome of the JFFS for the first time, in order to establish a baseline for future studies of host-microbial-environment interactions and monitoring programs. During two consecutive reproductive seasons, 57 faecal samples were collected from 7 different JFFS colonies within the Juan Fernandez Archipelago, Chile. Bacterial composition and abundance were characterised by sequencing the V4 region of the 16S rRNA gene. The overall microbiome composition was dominated by five phyla: Firmicutes (40 % ± 24), Fusobacteria (30 % ± 17), Bacteroidetes (22 % ± 10), Proteobacteria (6 % ± 4) and Actinobacteria (2 % ± 3). Alpha diversity was higher in Tierras Blancas. However, location was not found to be a dominant driver of microbial composition. Interestingly, the strongest signal in the data was a negative association between the genera Peptoclostridium and Fusobacterium, which explained 29.7 % of the total microbial composition variability between samples. The genus Peptoclostridium has not been reported in other pinniped studies and its role here is unclear, with interpretation challenging due to a lack of information regarding microbiome functionality in marine mammals. As a first insight into the JFFS faecal microbiome, these results contribute towards our understanding of the natural microbial diversity and composition in free-ranging pinnipeds.