The Atlantic puffin (Fratercula arctica) is a seabird species characterized by great diving capabilities and transoceanic migratory behavior. These movements contribute to the dispersion of the species during migration, and episodes of mortality associated with migration may be a normal event in the dynamic of the Atlantic puffin populations. This study aimed to describe the anatomopathological findings of an unusual mortality event of Atlantic puffins observed during the non-breeding period along the coast of the Canary Islands. The most consistent gross finding during necropsy was generalized muscle atrophy and fat depletion. The main histological findings were centered in the urinary tract, with dilation and inflammation of the primary ureter branch and medullary cones, and intraluminal trematodes identified as Renicola sloanei based on morphology and molecular analysis. Influenza virus infection was ruled out. The postmortem investigations performed in this mortality event of Atlantic puffins indicate that the animals were severely emaciated and suffered from nephropathy. The etiopathological investigation performed in relation to this mortality event of Atlantic puffins indicates starvation associated with bad weather conditions during migratory movement as the most likely cause of the unusual mortality event.

Avian poxvirus was diagnosed in eight wild Stone-curlews (Burhinus oedicnemus) from the Canary Islands, based on a combination of pathological and molecular analysis. Affected birds exhibited lesions consistent with poxvirus infection; three of four with mild lesions (≤2 on pelvic limbs, excluding phalanges) were successfully rehabilitated and released, while four with moderate (≤2 on phalanges) to severe lesions (≥3 on phalanges) potentially faced impaired mobility, increased predation risk, and reduced foraging efficiency. Histopathology of six individuals revealed Bollinger bodies, characteristic of Avipoxvirus infection, and molecular analysis confirmed the presence of viral DNA in six cases. Three genetically distinct viral variants were identified, each associated with different phylogenetic clades and subclades, suggesting substantial viral diversity within this host species. Co-infection with Aspergillus fumigatus was also detected in six of the eight birds, confirmed by molecular analysis in either skin lesions or lung tissue. To our knowledge, this represents the first report of A. fumigatus co-infection in Stone-curlews with Avipoxvirus. Additionally, one individual presented a tumor-like lesion, expanding the known pathological manifestations of the disease. These findings provide new insights into avian pox and highlight the importance of considering fungal co-infections in the differential diagnosis, given their potential to exacerbate disease severity.

Avian haemosporidians are globally distributed protozoan parasites transmitted by hematophagous vectors, yet information on their occurrence in the Stone-curlew (Burhinus oedicnemus), particularly from the Canary Islands, is scarce. Between 2020 and 2024, 47 Stone-curlews were examined for Haemoproteus, Plasmodium, and Leucocytozoon spp. using nested PCR targeting the cytochrome b gene, followed by sequencing and phylogenetic analysis. Histopathological examination was performed on formalin-fixed tissues. Leucocytozoon sp. DNA was detected in one individual (case FS415/23), with identical sequences amplified from multiple organs. Phylogenetic analysis placed this isolate within lineage CIAE02, previously reported in raptors and other avian taxa. Microscopic evaluation revealed megalomeronts in the liver, kidney, and skin, consistent with Leucocytozoon infection. Despite concurrent infection with Avipoxvirus and Aspergillus fumigatus, no prominent inflammatory reaction surrounded the haemosporidian tissue states. The only prior haemosporidian reported in Burhinus is Haemoproteus burhinus, described from B. oedicnemus saharae in Iraq, and no Leucocytozoon infections have previously been recorded in this genus. Therefore, this represents the first evidence of Leucocytozoon infection in the Stone-curlew, extending the known host range of lineage CIAE02. These findings highlight the relevance of integrative diagnostic approaches for detecting latent or cryptic haemosporidian infections in non-passerine avian hosts.

The Atlantic puffin (Fratercula arctica) is a charadriiform bird characterized by great diving capabilities, and transoceanic migratory behavior. These movements contribute to the dispersion of the species during migration, and episodes of mortality associated with migration may be a normal event in the dynamic of the Atlantic puffin populations. This study aimed to describe the anatomopathological findings of an unusual mortality event of Atlantic puffins observed during late 2022 and early 2023 along the coast of the Canary Islands. The most consistent gross finding during necropsy was generalized muscle atrophy and fat depletion. Main histological findings centered in the urinary tract with dilation and inflammation of the primary ureter branch and medullary cones, and intraluminal trematodes identified as Renicola sloanei based on morphology and molecular analysis. Influenza virus infection was ruled out in this mortality. The postmortem investigations performed in this mortality event of Atlantic puffins indicates that the animals were severely emaciated and suffered from nephropathy. The etiopathological investigation performed in this mortality event of Atlantic puffins indicates starvation associated with bad weather conditions during a migratory movement as the most likely cause of the unusual mortality event.

Background: Despite the popularity of elasmobranchs in zoos and aquariums, data on hematological values for health monitoring remain limited, particularly for wild populations. In this study, reference intervals for key hematological parameters and blood pH were established from blood samples of 49 adult females of the Critically Endangered Spiny Butterfly Ray (Gymnura altavela) collected across three shallow beaches in the Canary Islands. Additional data were obtained from four adults maintained under human care. To our knowledge, this is the first report of hematological and blood pH reference intervals for free-ranging G. altavela. Results: Lymphocytes (56%) were the dominant leukocyte, followed by heterophils (23.6%), eosinophils (16.7%), monocytes (2%), neutrophils (1.1%), and basophils (0.2%). Median values included 356.6 × 103 cells/µL for red blood cell count (RBC), 31.7 × 103 cells/µL for white blood cell count (WBC), 28.2% for packed cell volume (PCV), and 8.1 g/dL for total plasma solids (TS). Blood pH averaged 7.25, rising to 7.38 with temperature correction. These values remained consistent across reproductive states and housing conditions, suggesting minimal physiological disruption. Conclusion:: This study highlights the effectiveness of rapid, low-stress sampling and provides essential baseline data to support veterinary care and conservation strategies for G. altavela. Expanding future research with a larger sample size will enhance understanding of health variations by age, sex, and reproductive status.

Despite the popularity of elasmobranchs in zoos and aquariums, data on hematological values for health monitoring remain limited, particularly for wild pop