Background: Eye-related neoplasms in dogs have a significant impact on visual ability, comfort, and longevity. Therapeutic alternatives and prognosis vary according to type of neoplasm and its anatomical location. Objective: To describe the frequency and distribution of eye-related neoplasms affecting dogs in Aburrá valley (Antioquia province, Colombia). Methods: A retrospective collection of eye-related neoplasms in dogs, diagnosed at the Animal Pathology Laboratory of Universidad de Antioquia (Colombia), was conducted. Data spanning from years 2005 to 2017 were used. Records included age, sex, breed, neoplasm type and location, and cellular origin of neoplasm. A total of 250 eye-related-neoplasm reports affecting 246 dogs were analyzed -one report per animal, with the exception of four animals with both eyes simultaneously affected by the same type of neoplasm. Results: Animals between 8 and 11 years of age were more frequently affected by eye-related neoplasms (43.9%). Labrador retriever (19.1%), mixed-breed dogs (13.4%), and Poodle (12.2%) were the most frequently affected breeds. Neoplasms affected the eyelid in 76.8% of cases. Meibomian gland adenoma was the most frequent neoplasm (22.8%), followed by Meibomian gland epithelioma (20.0%), squamous cell carcinoma (8.8%), and melanocytoma (7.2%). The cellular origin of neoplasms [i]was epithelial in 73.6% of the cases. Conclusion: Meibomian gland adenoma was the most common eye-related neoplasm. To our knowledge, this is the first retrospective report aimed to eye-related neoplasms in dogs published in Colombia.

Background/Objetives: This study standardized a chemically induced colorectal cancer (CRC) model using azoxymethane (AOM) and dextran sodium sulfate (DSS) in BALB/c mice, replicating the progression from preneoplastic lesions to adenocarcinoma observed in human colorectal carcinogenesis. Methods: The CCR-AOM/DSS model was standardized in male and female BALB/c mice. Two protocols were tested. Subsequently, the positive control group was established with nine evaluation points. Tumor progression was characterized histopathologically and corroborated by methylene blue staining and scanning electron microscopy. Results: Two cycles of 2% DSS combined with a single injection of AOM (10 mg/kg) were necessary to induce adenocarcinoma in 100% of the mice, with no significant sex-based differences in tumor development. Females showed earlier tumor susceptibility under certain protocols. Inflammatory processes played a critical role in tumorigenesis, with neutrophil infiltration and fibrosis observed. Conclusions: The findings align with previous reports, emphasizing the influence of DSS cycles, molecular weight, and mouse strain on model outcomes. This standardized model provides a reliable platform for the preclinical evaluation of novel preventive and therapeutic strategies for CRC.

Background: Trypanosoma evansi is the most common protozoan in tropical and subtropical regions of the world, due to its ability to maintain and be transmitted by vectors such as Stomoxys spp. and Tabanus spp. This protozoan causes high morbidity and mortality rates in horses in African, American and Asian countries. In the years 2021 and 2022, a high mortality rate was reported among horses with symptoms associated with Trypanosoma spp. in the municipality of Arauca, department of Arauca, Colombia. The investigation described here was therefore carried out, seeking to identifythe pathogens and risk factors that led to the death of the horses in this region of Colombia.Cases: Blood samples were collected from Colombian criollo horses and dogs, as were samples of ticks, flies and horseflies that infested the horses. A variety of tissue samples were removed from the horses a few min after their death for histopathological analysis. Two questionnaires were applied to obtain information about the horses and the environment in which they live. The results of the clinical examination revealed pale mucous membranes, jaundice, high fever, dehydration and lethargy. The horses were also infested with Amblyomma mixtum (17.6%) and Dermacentor nitens (82.4%) ticks, and with Tabanus pungens (74%), Tabanus spp. (26%), and Stomoxys calcitrans flies (100%), while the dogs were infested with Rhipicephalus sanguineus s.l. (77.7%) and Amblyomma mixtum (22.2%) ticks. The blood smear test results revealed the presence of Trypanosoma spp. in 66.6% (n = 4) of the horse blood samples, and in 50% (n = 1) of the dog blood samples. PCR performed to identify the Trypanosoma species confirmed the presence of T. evansi. Histological examination of the spleen revealed the involvement and dissemination of T. evansi in the tissues. The horses also showed the presence of Equine Infectious Anemia Virus (EIAV).Discussion: This is the first updated specific report of T. evansi in criollo horses in the savannah flood zone of the municipality of Arauca, Colombia. The main risk associated with T. evansi infection in horses was found to be infestation with the natural vector T. pungens and the mechanical vector S. calcitrans, which are efficient ectoparasites for the transmission of this parasite. The presence of T. evansi in dogs represents a constant risk to horses, because dogs may serve as a reservoir for the maintenance of the hemoparasite in the population under study. Another risk factor for horses could be the presence of vampire bats (Desmodus rotundus), a species of bat that has been described as a vector and reservoir of T. evansi in Colombia. The presence of EIAV antibodies in the horses under study can be attributed to the exposure of sick horses to vectors of this virus, such as Tabanus spp., S. calcitrans and inanimate needle-shaped fomites. This is the first study that identifies the coinfection of T. evansi and EIAV in horses in the floodplain region of Colombia. In view of the importance of these 2 pathologies to the health of horses, a greater number of tests and a larger animal population will be required to determine if this coinfection is the cause of the death of criollo horses in this region of Colombia. Lastly, the owners reported that pharmacological control with trypanocides has not been successful in most of the outbreaks that occurred during the years 2021 and 2022. This may suggest that Trypanosoma evansi is developing resistance to these drugs; therefore, specific studies will be required in the future to test this hypothesis.Keywords: Arauca, Equine Infectious Anemia Virus, floodplain savannah, mortality, surra.

Mouth-related neoplastic and non-neoplastic lesions are commonly found in dogs and cats, and their diagnosis and classification are important for treatment planning and prognosis. This retrospective study analyzed mouth-related lesions in dogs and cats between 2000-2019 from the animal pathology laboratory of the Universidad de Antioquia, Medellín, Colombia. A total of 640 mouth-related lesions affecting 572 dogs (89.4%) and 68 cats (10.6%) were reviewed. Lesions were classified as neoplastic or non-neoplastic. The average age for neoplastic lesions was 8.6 years in dogs and 6.4 years in cats, while for non-neoplastic lesions the average age was 7.7 years for dogs and 5 years for cats. Data was analyzed using descriptive statistical methods according to year and source of report, demographic information for the animal, location of the lesion, and diagnosis. Tissue origin and behavior were variables considered for neoplastic lesions. Melanoma was the most common neoplasia in dogs and squamous cell carcinoma was most common in cats. The most frequent non-neoplastic lesion in dogs was gingival hyperplasia, while in cats the inflammatory lesions showed a wide range of morphological diagnoses. This study described many pathological lesions affecting the oral cavity for both dogs and cats and provides useful epidemiological data for both pathologists and clinicians.

Background: Bone Marrow Aspirate (BMA) allows the study, staging and monitoring of multiple conditions with bone marrow involvement. The BMA report is a crucial component of the post-analytical stage and significantly influences the veterinarian's understanding and decision-making process. Objective: To describe the zoographic, clinical, and quality characteristics of BMA reports, as well as the frequency of diagnoses and associated factors in dogs and cats treated at veterinary centers in Colombia from 2012 to 2023. Methods: This was a cross-sectional descriptive study. Data on zoographic and clinical variables were extracted from BMA reports and consultations; the frequency of diagnoses and associated factors were determined. Adherence to reporting quality was evaluated using established guidelines for BMA in dogs, cats, and humans. Results: A total of 135 BMA reports were reviewed from eight veterinary institutions: 116 for dogs and 19 for cats, with a mean age of 5.22 ± 3 years; 53% were males. The most common indication for BMA was anemia, alone or with other abnormalities. The least adhered-to reporting elements were puncture site (91.9%), relevant clinical data (85.2%), and morphological evaluation by cell line (52.6%). Additionally, 27.4% of the reports were excluded due to poor sample quality. The most frequent diagnosis in dogs was hypoplasia (36.1%), while in cats, it was neoplasia (40.0%). Erythroid hyperplasia and neoplasms were more prevalent in males, whereas granulocytic hypoplasia was more common in females. Conclusions: BMA as a diagnostic tool in dogs and cats in Colombia is rare. A significant proportion of samples did not meet quality criteria, and there was low adherence to reporting guidelines.

Splenic neoplastic and non‐neoplastic lesions are frequently diagnosed in dogs and often exhibit overlapping clinical signs and gross morphological features, rendering histopathological examination essential for definitive diagnosis, therapeutic planning, and prognostic assessment. In Colombia, epidemiological data regarding these lesions remain limited, whereas international studies report considerable heterogeneity in the relative frequencies of neoplastic and non‐neoplastic conditions. This study aimed to characterize the histopathological spectrum of splenic lesions in dogs and provide updated regional epidemiological data. A retrospective analysis was conducted on splenic specimens obtained from dogs subjected to total splenectomy between January 2019 and June 2024. All samples were processed and examined histopathologically at three veterinary pathology laboratories in Medellín, Colombia. Descriptive statistical analyses were performed considering year of submission, patient demographic data, morphological diagnosis, and concurrent histopathological findings. A total of 424 cases were evaluated, of which 282 (66.5%) corresponded to non‐neoplastic lesions and 142 (33.5%) to neoplastic processes. The mean age of dogs with non‐neoplastic lesions was 9.5 (< 1–16) years, whereas dogs with neoplastic lesions had a mean age of 10.2 (4–17) years. Splenitis was the most frequent non‐neoplastic diagnosis, accounting for 54.6% of cases and demonstrating a higher prevalence than reported in prior literature. Among malignant splenic neoplasms, hemangiosarcoma was the predominant diagnosis, representing 69.2% of cases. This study demonstrates a high prevalence of non‐neoplastic splenic lesions, particularly splenitis, and a frequent occurrence of multiple concurrent morphological diagnoses in non‐neoplastic cases. These findings provide novel regional epidemiological data and contribute original information to international literature, underscoring the importance of histopathological splenic evaluation for accurate diagnosis and clinical decision‐making.