Carlos Andrés Flores Olivares

The olive ridley turtle (Lepidochelys olivacea) is the second smallest and most abundant of the seven sea turtle species worldwide, currently distributed across approximately 80 countries. However, due to various anthropogenic and environmental pressures, its populations are declining and categorized as “Vulnerable” by the IUCN. Postmortem macroscopic and microscopic examination detected spirorchiids and associated lesions in six adult female olive ridley turtles is described herein, with strandings occurring along the Northern and Central-Northern Chilean coast between September 2024 and January 2026. Gross findings included alterations in the gastrointestinal, reproductive, and vascular systems, characterized by transmural granulomatous lesions and mucosal thickening. Histopathological analysis confirmed the presence of these cryptic parasites in multiple organs, including the intestine, reproductive tract, vasculature, liver, spleen, and adrenal glands, with varying degrees of severity. These findings confirm the presence of spirorchiidiasis in olive ridley turtles in Chile, which may have contributed to stranding and mortality events in some individuals. Molecular characterization is essential to determine whether this agent corresponds to a known species or represents a previously unreported spirorchiid taxon in the Southeastern Pacific.

The olive ridley turtle (Lepidochelys olivacea) is the second smallest and most abundant of the seven sea turtle species worldwide, currently distributed across approximately 80 countries. However, due to various anthropogenic and environmental pressures, its populations are declining and categorized as "Vulnerable" by the IUCN. This study describes the post-mortem macroscopic and microscopic detection of spirorchiids and associated lesions in six adult female olive ridleys stranded along the Northern and Central-Northern Chilean coast between November 2024 and January 2026. Macroscopic findings primarily revealed alterations in the gastrointestinal, reproductive, and vascular systems, characterized by transmural granulomatous lesions and mucosal thickening. Histopathological analysis confirmed the presence of these cryptic parasites in multiple organs, including the intestine, reproductive tract, vasculature, liver, spleen, and adrenal glands, with varying degrees of severity. These findings confirm the presence of spirorchiidiasis in olive ridley turtle in Chile, which may be directly or contributorily associated with stranding and mortality events. Molecular characterization is essential to determine whether this agent corresponds to a known species or represents a novel cryptic parasite taxon in the South-Eastern Pacific.

Humboldt penguins (Spheniscus humboldti) are classified as Vulnerable and listed in Appendix I of CITES, making the investigation of stranding and mortality causes essential for their conservation. This study describes the post-mortem findings of five Humboldt penguins stranded along the Chilean coast during 2025, focusing on renal and ureteral lesions associated with trematode infection. Gross examination revealed multifocal to coalescing renal lesions, including intrapelvic white purulent material and marked thickening of the ureteral walls. Histopathological analysis demonstrated moderate to severe renal and ureteral inflammation, characterized by intratubular and intraureteral trematodes associated with tubular degeneration, interstitial inflammation and fibrosis, vascular alterations, occasional glomerular changes, and severe ureteritis. Morphological and morphometric analyses of adult parasites obtained from histological renal sections confirmed the presence of trematodes. On clinical evaluation, stranded animals presented with lethargy, no evidence of external trauma, and body condition ranging from normal to emaciated. These findings confirm the presence of trematode-associated nephropathy and ureteropathy in Humboldt penguins. To our knowledge, this is the first report worldwide linking renal and ureteral parasitosis to disease in this species. Further molecular analyses are required to achieve definitive etiological identification and to support the recognition of this condition as an emerging disease relevant to conservation strategies for Humboldt penguins.

Humboldt penguins (Spheniscus humboldti) are classified as Vulnerable and listed in Appendix I of CITES, making the investigation of stranding and mortality causes essential for their conservation. This study describes the post-mortem findings of five Humboldt penguins stranded along the Chilean coast during 2025, focusing on renal and ureteral lesions associated with trematode infection. Gross examination revealed multifocal to coalescing renal lesions, including intrapelvic whitish purulent material and marked thickening of the ureteral walls. Histopathological analysis demonstrated moderate to severe renal and ureteral damage characterized by intratubular and intraureteral trematodes associated with tubular degeneration, interstitial inflammation and fibrosis, vascular alterations, occasional glomerular changes, and severe ureteritis. Morphological and morphometric analyses of adult trematodes and their eggs were performed, and mean values with standard deviations were obtained. Clinical evaluation of live-stranded penguins did not reveal overt signs of renal disease, highlighting the subclinical nature of this condition. These findings confirm the presence of trematode-associated nephropathy and ureteropathy in Humboldt penguins. To our knowledge, this is the first report worldwide linking renal and ureteral parasitosis to disease in this species. Further molecular analyses are required to achieve definitive etiological identification and to support the recognition of this condition as an emerging disease relevant to conservation strategies for Humboldt penguins.

In 2020, hundreds of thousands of dogs in Chile were exposed to toxic copper levels in commercial dog food, exceeding the legal copper limit tenfold. We report three fatal hepatic cirrhosis cases after at least three months of consumption of this product. All showed advanced stage liver injury, micro and macroscopic lesions, and high hepatic copper levels.

Maternal behavior in mammals is critical for offspring survival and provides insight into the evolutionary pressures shaping reproductive strategies. Postmortem attentive behavior (PAB) is a rare form of epimeletic behavior in which individuals show attachment, distress, or curiosity toward deceased conspecifics, most often between mothers and offspring. While PAB has been documented in terrestrial mammals and cetaceans, it has been rarely documented in pinnipeds. Here, we describe multiple instances of maternal PAB in the Antarctic apex predator, the leopard seal ( Hydrurga leptonyx ), at two sites in Patagonia, Chile. We document PAB in two adult females, including repeated observations of one individual across three years. One female displayed PAB for up to 20 days—the longest documented case in pinnipeds and among the longest for any mammal. Behaviors included carrying and mouthing the pup, maintaining close proximity, and displaying territoriality over the carcass. We also conducted a necropsy on one pup, yielding the first detailed anatomical assessment of this species at an early life stage. Our findings suggest death due to emaciation, likely from inadequate nursing. As no pups have been observed surviving to weaning in Chile, potential drivers of high preweaning mortality may include habitat instability, genetic load, or insufficient maternal investment. This study offers novel insight into leopard seal reproductive biology, highlighting the need for continued monitoring of this Antarctic seal.

In hematological malignancies, autologous immunotherapy with T lymphocytes expressing a chimeric antigen receptor (CAR-T) has been successfully applied. CAR enhances the immuno-cellular effector system directly against cells expressing target antigens. The objective here was to discuss the prospects of applying CAR-T and its variants in autoimmune diseases (AIDs) to deplete pathogenic autoantibodies by eliminating B lymphocytes and plasma cells. B cells play a crucial role in the pathogenesis of AID through the production of autoantibodies, cytokine dysregulation, antigen presentation, and regulatory dysfunction. In AID with numerous autoreactive clones against various autoantigens, such as systemic lupus erythematosus, rheumatoid arthritis, vasculitis, myositis, and systemic sclerosis, CAR-T targeting CD19/CD20 and B-cell maturation antigen (BCMA) have shown success in preclinical and clinical studies, representing an innovative option for refractory patients when standard treatments fail. The suppression of B lymphocytes reactive against specific antigens using cytolytic T cells carrying a chimeric autoantibody receptor (CAAR-T) offers a promising approach for managing various AIDs, especially those with characterized pathogenic autoantibodies, such as pemphigus vulgaris, myasthenia gravis, and anti-NMDAR autoimmune encephalitis. CAAR-T allows the elimination of autoreactive B lymphocytes without compromising the general functionality of the immune system, minimizing common side effects in general immunosuppressive therapies, including immunobiologicals and CAR-T. In vitro, preclinical, and clinical (phase 1) studies have demonstrated the efficacy and specificity of CAR-T and CAAR-T in several AIDs; however, extensive clinical trials (phase 3) are required to assess their safety and clinical applicability. These advances promise to enhance precision medicine in the management of AIDs, offering personalized treatments for individual patients.

El selenio (Se) es un componente indispensable dentro de los sistemas antioxidantes del organismo animal, lo que permite su correcto mantenimiento y desarrollo. Por este motivo, su deficiencia se encuentra relacionada con una serie de trastornos oxidativos, que se traducen en una mala salud, reproducción y rendimiento productivo en general. El objetivo del presente estudio fue evaluar el balance metabólico nutricional de Se, a través de la medición de las concentraciones sanguíneas del mineral en un establecimiento rural ubicado en la zona central de Chile, en donde existen antecedentes de episodios de mortandad compatibles con su deficiencia. Para esto, se tomaron muestras sanguíneas de caprinos pertenecientes al establecimiento (n = 32), las cuales fueron analizadas mediante espectrofotometría de absorción atómica en el laboratorio de bioquímica de la Estación Experimental Agropecuaria del Instituto Nacional de Tecnología Agropecuaria, ubicado en Balcarce, Argentina. Se obtuvo un promedio de Se sanguíneo de 34,16 ± 14,81 ppb, en donde el 100 % de los animales analizados presentaron valores inadecuados para la especie. En el caso de los caprinos juveniles (n = 5), se obtuvo un promedio de 18,48 ± 8,51 ppb. En el ganado adulto (n = 27), los valores bordearon concentraciones de 8,12 y 63,35 ppb. Se concluye que existe una deficiencia de Se crítica en los animales muestreados pertenecientes al establecimiento ubicado en la zona central de Chile

Ulcers of the oral cavity, esophagus, and gastric compartments of South American camelids are uncommon. Multifocal-to-coalescing ulcers were identified in the oral cavity, esophagus, and/or gastric compartments of 5 alpacas submitted for postmortem examination. Fusobacterium necrophorum was isolated from the lesions in all alpacas, in combination with other aerobic and anaerobic bacteria. In 4 of these cases, F. necrophorum–associated lesions were considered secondary to neoplasia or other chronic debilitating conditions; in 1 case, the alimentary ulcers were considered the most significant autopsy finding. It is not known if this agent acted as a primary or opportunistic agent in mucosal membranes previously damaged by a traumatic event, chemical insult, immunodeficiency, or any other debilitating condition of the host.

A small dairy goat farm in central Chile stocked their troughs with ornamental plants and grasses, which were obtained after pruning the gardens of neighboring sectors. Twelve hours after the goats ingested this food, the farm registered a death toll of eight goats, all of which were adult females in their productive stage, before entering the milking parlor. The mortality episode lasted 84 hours and produced mortality and morbidity values of 48 and 54 percent, respectively (n = 52). During a visit to the farm, clinic inspections, autopsies, and sample tissues were obtained for microscopic analysis (the tissues specimens were fixed in 10% buffered formaldehyde solution). The clinic inspection and microscopic analysis both confirmed that the animals had cardiovascular disease. The lesions were compatible with those produced by cardiac glycosides. During the site visit, Nerium oleander was found in the troughs, which suggested that the animals were poisoned by eating this plant. There was a high presence of this plant in the poisoned area, and it was not associated with the mortality episode before the on-site visit, which indicates that the authors should conduct training and inform producers about the handling and feeding of their animals