Alejandro de la Peña-Moctezuma

The bacterial Quorum Sensing system refers to the recognition of signaling molecules called autoinducers produced by bacteria when a certain cell density is reached in the environment. Those cell-density-dependent autoinducers regulate and coordinate diverse functional processes, such as bioluminescence, biofilm production, sporulation, and even the expression of some virulence factors, among others. There is a wide variety of autoinducers, and for Gram-negative bacteria, the canonical autoinducers are the N-acyl-homoserine lactones (AI-1). Presently, the production of autoinducers in Leptospira has not been described; therefore, the objective of this study was to detect and identify autoinducers in this bacterial genus. We report here the expression of AI-1 in cultures ≥2.4 × 10⁸ of Leptospira meyeri. Ethyl acetate extracts of Leptospira culture supernatants were capable of activating the β-galactosidase system in the biosensor Agrobacterium tumefaciens strain NTL4. Partial identification of the leptospiral supernatant extracts was done by thin-layer chromatography (TLC), showing a similar retention factor to the synthetic standard N-Octanoyl-DL-homoserine lactone (C8-AHL) in the Leptospira supernatant extracts. In addition, infrared spectroscopy (IR) analysis showed peaks corresponding to the lactone and amide groups in both the C8-AHL standard and the Leptospira meyeri culture extracts. Moreover, High-Performance Liquid Chromatography–Mass Spectrometry (HPLC-MS/MS) confirmed the same retention time (10.7 ± 0.1 min) in both the Leptospira meyeri supernatant extracts and the C8-AHL standard. These results show that Leptospira meyeri synthesizes N-acyl homoserine lactone family autoinducers, particularly the N-Octanoyl-DL-homoserine lactone, and lay the groundwork for future research on Quorum Sensing systems in Leptospira.

Ovine Respiratory Complex is a multifactorial disease involving interactions between pathogens, host factors, and environmental conditions. This study investigated associations between selected bacterial agents, including Mycoplasma ovipneumoniae infection and members of the Pasteurellaceae family, and clinical, auscultatory, ultrasonographic, and post-mortem findings in Lacaune fattening lambs. A total of 80 animals were evaluated using clinical examination, thoracic auscultation, ultrasonography, post-mortem assessment, bacteriological culture, and quantitative PCR (qPCR) for Mycoplasma ovipneumoniae. Associations between microbial detection and disease severity scores were analyzed. Mycoplasma ovipneumoniae was the most frequently detected organism (50%), followed by Pasteurella multocida (32.9%) and Trueperella pyogenes (27.8%). Detection of specific microorganisms was more frequently observed in animals with increased disease severity across multiple diagnostic modalities. Coinfection was identified in 60.8% of animals and was significantly associated with increased severity according to clinical, auscultatory, ultrasonographic, and post-mortem scores. These findings underscore the polymicrobial nature of ORC and emphasise the necessity of employing complementary diagnostic approaches for disease evaluation.

Compendio de revisiones en ciencias veterinarias, agroforestales, pesqueras y áreas afines La presente obra colectiva reúne una diversidad de investigaciones aplicadas que reflejan el dinamismo, la pertinencia y el compromiso científico de las ciencias agropecuarias y veterinarias de México, donde los capítulos ofrecen soluciones innovadoras, diagnósticos precisos y propuestas de mejora continua que responden a las necesidades de los territorios rurales, los sistemas alimentarios y la salud integral. Desde el mejoramiento genético de cultivos estratégicos como el frijol y la soya, hasta el uso de microorganismos benéficos. En el ámbito pecuario, se documentan prácticas tecnológicas en ranchos ganaderos, estrategias nutricionales para cabritos y pollos de engorda, así como obtener los parámetros reproductivos en sistemas familiares. También se incluyen reflexiones sobre la educación veterinaria, las progresiones de aprendizaje y la evaluación por competencias, que invitan a repensar la formación profesional desde la pertinencia curricular y la transformación pedagógica. Esta obra es testimonio del talento académico, la vocación territorial y el compromiso ético de quienes investigan, enseñan y transforman desde las ciencias agrícolas, pecuarias y del mar. Su lectura permitirá al lector comprender la complejidad de los sistemas agropecuarios y veterinarios, y valorar las soluciones que emergen desde la ciencia aplicada con impacto local y resonancia global. Sergio Martínez González, Fidel Avila Ramos, Carlos Omar de la Cruz Moreno. Editores. Editorial: Abanico Académico Primera edición y Versión Digital, publicado en Tepic, Nayarit, México el 10-12-2025, con 642 páginas. ISBN: 978-607-26738-2-3 DOI: 10.21929/abanico/2025.2 URL: https://doi.org/10.21929/abanico/2025.2 Compendio de revisiones en ciencias veterinarias, agroforestales, pesqueras y áreas afines en su primera edición, es publicada en versión digital con 642 páginas, después del proceso de arbitraje y dictaminación por pares, nacional e internacional. De acuerdo a la Ciencia Abierta puede ser reproducida o transmitida, mediante cualquier sistema o método, electrónico o mecánico, con fines académicos y sin fines de lucro.

The objective of this study was to determine the seroprevalence and factors associated with the presence of antibodies against 12 Leptospira serovars in dogs (Canis lupus familiaris) from urban areas of Zacatecas, Mexico. Serum samples from 279 animals were analyzed using the Microscopic Agglutination Test (MAT), with a panel of 12 serovars. Additionally, a questionnaire was administered to identify potential factors associated with seropositive status. Overall seropositivity was 80.6% (95% CI = 75.9–85.3%). The Grippotyphosa serovar showed the lowest seroprevalence (3.2%, 95% CI = 1.1–5.3%), while Icterohaemorrhagiae had the highest (43.3%, 95% CI = 37.5–49.2%). The remaining serovars showed seropositivity ranging from 10.3% (95% CI = 6.7–13.9%) to 36.2% (95% CI = 30.5–41.9%). Habitat was a significant factor (P = 0.0026), with stray dogs showing higher seropositivity (86.3%, 95% CI = 81.1–91.5%) compared to owned dogs (71.8%, 95% CI = 63.3–80.2%). This study revealed a high seropositivity of Leptospira in dogs from urban areas of Zacatecas, Mexico, representing a potential animal health concern and a public health risk for the human population. http://dx.doi.org/10.21929/abavet2025.10 2024-18 https://www.youtube.com/watch?v=JgpaFco1P1E El objetivo del estudio fue determinar la seroprevalencia y los factores asociados a la presencia de anticuerpos contra 12 serovariedades de Leptospira en perros (Canis lupus familiaris) de zonas urbanas de Zacatecas, México. Se analizaron muestras séricas de 279 animales mediante la Técnica de Aglutinación Microscópica (MAT), utilizando un panel de 12 serovariedades. Además, se aplicó un cuestionario para identificar los posibles factores asociados con el estado seropositivo. La seropositividad general fue del 80.6 % (IC 95% = 75.9 – 85.3 %). La serovariedad Grippotyphosa presentó la menor seroprevalencia (3.2%, IC 95% = 1.1 – 5.3 %), mientras que Icterohaemorrhagiae fue mayor (43.3%, IC 95% = 37.5 – 49.2%). El resto de las serovariedades obtuvieron una positividad entre 10.3 % (IC 95 % = 6.7 – 13.9%) y 36.2% (IC 95 % = 30.5 – 41.9%). El factor hábitat fue significativo (P = 0.0026), Se observó una mayor seropositividad en perros callejeros (86.3 %, IC 95 % = 81.1 – 91.5%) vs. perros con dueño (71.8 %, IC 95 %= 63.3 – 80.2). Este estudio reveló una alta seropositividad de Leptospira en perros en zonas urbanas de Zacatecas, México, lo que representa un potencial problema de salud animal y un problema de salud pública para la población humana. http://dx.doi.org/10.21929/abavet2025.10 2024-18 https://www.youtube.com/watch?v=JgpaFco1P1E http://dx.doi.org/10.21929/abavet2025.10 2024-18. https://www.youtube.com/watch?v=JgpaFco1P1E

The aim of this study was to evaluate the relationship between seroprevalence of chronic diseases, hair cortisol concentration (HCC), and welfare of dairy goats housed throughout a productive cycle. Sixty multiparous dairy goats, over four years old, were selected. An animal welfare assessment was conducted using health indicators for goats, according to the AWIN protocol. Blood samples were also collected for haematology and determination of seroprevalence of chronic diseases, hair samples for determination of HCC, milk samples for chemical composition and somatic cell counts, and faecal samples for parasite load. Small Ruminant Lentivirus (SRLv) had a prevalence of 71.66%, Mycobacterium avium subspecies paratuberculosis (MAP) of 5%, Leptospira interrogans of 40% and Ovine Gammaherpesvirus type 2 (OvHV-2) of 50%. The percentages of goats that tested positive for one, two or three diseases were 31.67%, 50% and 11.66%respectively. Haematological alterations included hyperproteinaemia (84.94 ± 1.58 g/L) and hyperfibrinogenaemia (6.11± 0.65 g/L) for those with one or two diseases, with significant differences being found (P < 0.05). The welfare indicatorsrelated to health and the number of diseases were poor body condition, poor coat, poor udder conformation, andmucosal lesions (P < 0.05). However, no significant differences were observed between HCC and the number of chronicdiseases in dairy goats (P > 0.05). Higher concentrations of cortisol in hair were found at 150 days of lactation (16.65 ± 1.39pg/mg) compared to the mating season (9.55 ± 0.04 pg/mg) (P < 0.05). No associations were found (P > 0.05) betweenthe production, composition, and somatic cell counts in milk and cortisol concentrations and diseases. It was concludedthat the presence of chronic diseases in goats did not influence hair cortisol concentrations, possibly due to an effect ofadaptive tolerance to diseases, as occurs in other domestic species; however, there was an effect of the productive stage.

Leptospirosis is a neglected zoonotic disease that commonly affects cattle, pigs, horses, and dogs in many countries. Infection in dogs is usually subclinical, but acute cases of leptospirosis may occur along with systemic failure, which may become fatal. After recovery from an acute infection, dogs may become asymptomatic carriers and shed pathogenic leptospires through urine for long periods of time. Here, a study of ten different cases of leptospirosis is presented, showing the relevance of dogs as asymptomatic carriers of pathogenic Leptospira. The diagnosis was confirmed via isolation and further serological and genetic identification. Four Leptospira isolates (LOCaS28, 31, 34, and 46) were obtained from the kidneys and urine samples of 58 dogs destined for destruction (6.89%) at a Canine Control Center in Mexico City. No spirochetes were observed in the urine samples of those Leptospira-positive dogs examined under dark-field microscopy, and no clinical signs of disease were observed either. Six additional isolates were obtained: two came from asymptomatic carrier dogs (CEL60 and UADY22); another isolate came from an asymptomatic dog that was a pack companion of a clinically ill dog with fatal leptospirosis (AGFA24); and finally, three isolates were taken from dogs that died of leptospirosis (LOCaS59, Citlalli, and Nayar1). Nine out of the ten isolates were identified as being from the serogroup Canicola via cross-absorption MAT using reference strains and specific antisera, and their identity was genetically confirmed as Canicola ST34 via multi-locus sequencing typing (MLST). In contrast, the isolate Nayar1 was identified as serovar Copenhageni ST2. Interestingly, the asymptomatic dogs from which Leptospira isolates were recovered consistently showed high antibody titers in the microscopic agglutination test (MAT), revealing values of at least 1:3200 against serogroup Canicola and lower titer values against other serogroups. Isolates showed different virulence levels in the hamster model. Taken as a whole, all these findings confirmed that dogs may act as asymptomatic carriers of pathogenic leptospires and possibly spread them out to the environment, thus representing an active public health risk. The results also showed that the Canicola ST34 clone is the most prevalent Leptospira serovar in dogs in Mexico, and finally that the old-fashioned MAT is a good alternative for the detection of presumptive Leptospira asymptomatic carrier dogs.

The wide variety of pathogenic Leptospira serovars and the weak protection offered by the available vaccines encourage the search for protective immunogens against leptospirosis. We found that the secretin GspD of the type II secretion system (T2S) of Leptospira interrogans serovar Canicola was highly conserved amongst pathogenic serovars and was expressed in vivo during infection, as shown by immunohistochemistry. Convalescent sera of hamsters, dogs, and cows showed the presence of IgG antibodies, recognizing a recombinant version of this protein expressed in Escherichia coli (rGspDLC) in Western blot assays. In a pilot vaccination study, a group of eight hamsters was immunized on days zero and 14 with 50 µg of rGspDLC mixed with Freund’s incomplete adjuvant (FIA). On day 28 of the study, 1,000 LD50 (Lethal Dose 50%) of a virulent strain of Leptospira interrogans serovar Canicola (LOCaS46) were inoculated by an intraoral submucosal route (IOSM). Seventy-five percent protection against disease (p = 0.017573, Fisher’s exact test) and 50% protection against infection were observed in this group of vaccinated hamsters. In contrast, 85% of non-vaccinated hamsters died six to nine days after the challenge. These results suggest the potential usefulness of the T2S secretin GspD of Leptospira as a protective recombinant vaccine against leptospirosis.

Rodents are the main reservoirs of pathogenic leptospires, spreading the organism to the environment and so the major risk factor for both, animals and humans to acquire leptospirosis. To assess such a role, 50 mice (Mus musculus) were caught in a dairy farm in the municipality of Teoloyucan, State of Mexico in central Mexico. Anti-Leptospira antibody titers (≥1:20), were obtained in 46 % (23) of the animals by the microscopic agglutination test (MAT), where the most common serovars detected were: Ballum 38 % (19), Canicola 10 % (5) and Australis 2 % (1). Three Leptospira isolates (6 %) were obtained by culture of mice kidneys macerates. The cultures were identified as L. borgpetersenii serovar Ballum by cross-MAT, IS1533-based PCR assay, rrs2 (rRNA) sequencing, restriction fragment length polymorphism (RFLP) and by multiple locus sequencing typing (MLST). As far as we know, this is the first report on the isolation of L. borgpetersenii serovar Ballum recovered from Mus musculus in Mexico.