Stray dogs are one of the main reservoirs of intestinal parasitic infections and some have zoonotic potential. An epidemiological survey was carried out between September 2017 and May 2018 in Mexicali Valley, this area sacrifices around 92,470 head of cattle monthly, which represents 27% of the national slaughter and has 71,307 hectares for crops. In this period the Municipal Animal Control Center during their routine visits to the Mexicali Valley captured 103 dogs. All the dogs were evaluated using copromicroscopic techniques to detect intestinal parasites. The general frequency of parasitic infections was 28.15% (29/103), the most frequent parasite being Dipylidium caninum 16.50% (17/103), followed by Taenia spp. 6.79% (7/103), Taenia hydatigena 2.91% (3/103), Taenia serialis 0.97% (1/103), Taenia pisiformis (0.97%), Toxocara canis 3.88% (4/103), Toxascaris leonina 1.94% (2/103), and Cystoisospora spp. 1.94% (2/103). No significant statistical associations were found between parasitic infections and the studied variables (sex, age, and size) however; there was a significant statistical association with the capture area. Most of the parasites found in this survey have potential to affect the human population and animal production.

Escherichia coli is an opportunistic pathogen and a leading cause of Community-Acquired Urinary Tract Infections (CA-UTIs). E. coli can harbor multiple genetic resistant determinants, such as Extended Spectrum Beta-lactamases (ESBL) and Plasmid-Mediated Quinolone Resistance (PMQR) genes, complicating the empirical treatment of UTIs with β-lactams and quinolones. The aim of his study was to characterize ESBL and PMQR genes among E. coli isolates from CA-UTI in Mexicali, Mexico Isolates were collected from January to December 2023. Identification was performed by MALDI-TOF, and ESBL-producing determination and antimicrobial susceptibility by Vitek 2. Detection of ESBL and PMQR, and phylotyping were performed by PCR. Genetic diversity was determined by Enterobacterial Repetitive Intergenic Consensus Polymerase Chain Reaction (ERIC-PCR). Eighty-nine E. coli isolates were collected from CA-UTIs. All exhibited resistance to ciprofloxacin, ceftriaxone, and cefotaxime, while being susceptible to carbapenems and ceftazidime/avibactam. All isolates tested positive for an ESBL gene, with bla_CTX-M (98.9 %) being the most prevalent. Five isolates tested negative for PMQR genes; the remaining showed aac(6')-lb-cr present in 85.3 %. Coexistence between ESBL and PMQR genes was noted in 95.5 %. Most prevalent plylogenetic group was group B2 (74.2 %). This study provides valuable regional data, highlighting a public health problem due to the high prevalence of ESBL and PMQR genes in E. coli responsible for CA-UTI, which are linked to multidrug resistance. Genetic diversity was found, suggesting multiple sources of resistant strains in the community. These findings underline the need for surveillance and control to limit the spread of resistant E. coli, locally and globally. DATA SUMMARY: The authors confirm all supporting data, code, and protocols have been provided within the article or through supplementary data files.

The Mexican territory of the Yucatan Peninsula has a tropical climate and harbors a wide variety of domestic, synanthropic, and wild animals, as well as disease vectors. To determine the distribution of recorded zoonotic diseases in the Yucatan Peninsula, scientific publications referring to these diseases in animals and containing geographic coordinates of disease occurrence, were studied. The epidemiological bulletins of the national government were also consulted to obtain information on zoonotic diseases reported in humans in the territory. The territory harbors a wide variety of tropical zoonotic pathogens, including Trypanosoma cruzi, Leptospira interrogans, Toxoplasma gondii, Leishmania mexicana, Dirofilaria immitis, and Rickettsia felis. A variety of domestic, synanthropic, and wild animals act as hosts or reservoirs in the transmission cycle of the zoonotic diseases in the Yucatan Peninsula, and some spillover into human populations has also been recorded. There are still zoonotic diseases that have rarely or never been reported in humans, but it is not clear whether this is because these diseases in humans are not common, there is a lack of viable transmission cycle or there is a lack of appropriate diagnosis. It is necessary to continue monitoring vectors, animal hosts, and humans to identify risk factors for zoonotic diseases in the Yucatan Peninsula.

Ehrlichia and Anaplasma are obligate intracellular, gram-negative bacteria with tropism for hematopoietic cells, especially leukocytes and platelets. There are several Ehrlichia species that infect dogs. Ehrlichia canis is transmitted by Rhipicephalus sanguineus and replicates within monocytes and macrophages, leading to canine monocytic ehrlichiosis, a disease of worldwide distribution. The clinical signs are varied and non-specific. Anaplasma has two species that infect dogs, Anaplasma phagocytophilum and Anaplasma platys, the second also transmitted by Rhipicephalus sanguineus. This study aimed to evaluate the epidemiology and hematologic changes associated with the presence of Ehrlichia spp. and Anaplasma spp. coinfection in dogs from Baja California. Complete hematological analysis, examination of buffy coat smears, and ELISA tests were performed on blood samples from three veterinary diagnostic laboratories from Mexicali and Tijuana cities in Baja California, Mexico. A total of 5,469 dog samples were analyzed. The overall prevalence of Ehrlichia spp., was 4.79%, with a distribution of 6.3% in Mexicali (OR: 2.39 CI: 1.69-3.17) and 2.5% in Tijuana. The peak of infection was found in September. Contact with other dogs and tick infestation were the risk factors associated with infection (P < 0.05). There was 96% co-infection only in Tijuana and 0% in Mexicali. Anemia, thrombocytopenia, and hyperproteinemia are associated with Ehrlichia spp., and Ehrlichia/Anaplasma infection. In view of the foregoing, we have to maintain epidemiologic vigilance, as well as look further into the ticks present in the state and the possibility of transmission of unusual pathogens.

Cutaneous neoplasia is among the most common illnesses in dogs and can pose significant risks. Accurate morphological diagnosis of these conditions is vital for effective treatment and management. In this retrospective study, a total of 3746 canine skin biopsies were submitted to a veterinary reference diagnostic laboratory and evaluated using histopathology. The variables assessed included age, sex, breed, lesion, location, and histopathological diagnosis. Non-neoplastic lesions accounted for 61% of all analyzed samples, while neoplastic tumors accounted for 39%. When looking at age, dogs ranging 3–6 years and 7–9 years had at least six times higher risk of developing malignant neoplasia compared to those aged 0–2 years. Among the malignant neoplasms, mast cell tumors, hemangiosarcoma, and squamous cell carcinoma were the most observed, representing 30%, 18%, and 12% of cases, respectively. The breeds most frequently affected by malignant neoplasms included Pit Bull Terriers, Boxers, and mixed breeds, all of which comprised the majority of mast cell tumor cases at 50.54%. These findings are novel in this field and may assist small animal veterinarians in making preliminary diagnoses, while also helping pet owners understand the importance of skin cancer and its early detection.

Los ovinos son hospedadores intermediarios de cestodos gastrointestinales de perros. En Mexicali, México, se ha reportado infección por Taenia spp. en perros callejeros, con prevalencias del 3.9 al 6.79 %, siendo Taenia hydatigena la especie más frecuente. Sin embargo, se desconoce el hospedador intermediario de este parásito en la región. El objetivo de este estudio fue detectar, estimar la frecuencia, determinar los principales tejidos afectados y explorar factores asociados con la infección por el metacestodo de T. hydatigena (anteriormente conocido como Cysticercus tenuicollis) en ovinos de Mexicali. Se realizó un estudio transversal en dos unidades de producción ovina (UPO), mediante un muestreo por conveniencia por oportunidad no paramétrico de 91 ovinos. Se registró la UPO, el sexo y la edad, y todos los animales fueron sometidos a inspección postmortem. La frecuencia general fue de 81.3 % (74/91), con valores de 83.3 % (65/78) en la UPO-1 y 69.2 % (9/13) en la UPO-2. Las hembras presentaron una frecuencia de 88.3 % (38/43), mientras que en los machos fue de 75 % (36/48). En los animales menores de tres años la frecuencia fue de 76.2 % (45/59) y en los mayores de tres años de 90.6 % (29/32). Ninguna de las variables evaluadas se asoció con la presencia del metacestodo. De los casos positivos, el 71.6 % presentó afectación en un solo tejido, el 24.3 % en dos tejidos y el 4.0 % en tres o más tejidos. Los principales tejidos afectados fueron mesenterio, hígado y rumen. Este constituye el primer reporte del metacestodo de T. hydatigena en ovinos del noroeste de México.