Escherichia coli Strains Isolated from American Bison (Bison bison) Showed Uncommon Virulent Gene Patterns and Antimicrobial Multi-Resistance.

E. coli is considered one of the most important zoonotic pathogens worldwide. Highly virulent and antimicrobial-resistant strains of E. coli have been reported in recent years, making it essential to understand their ecological origins. In this study, we analyzed the characteristics of E. coli strains present in the natural population of American bison (Bison bison) in Mexico. We sampled 123 individuals and determined the presence of E. coli using standard bacteriological methods. The isolated strains were characterized using molecular techniques based on PCR. To evaluate the diversity of E. coli strains in this population, we analyzed 108 suggestive colonies from each fecal sample. From a total of 13,284 suggestive colonies, we isolated 33 E. coli strains that contained at least one virulence gene. The virotypes of these strains were highly varied, including strains with atypical patterns or combinations compared to classical pathotypes, such as the presence of escV, eae, bfpB, and ial genes in E. coli strain LMA-26-6-6, or stx2, eae, and ial genes in E. coli strain LMA-16-1-32. Genotype analysis of these strains revealed a previously undescribed phylogenetic group. Serotyping of all strains showed that serogroups O26 and O22 were the most abundant. Interestingly, strains belonging to these groups exhibited different patterns of virulence genes. Finally, the isolated E. coli strains demonstrated broad resistance to antimicrobials, including various beta-lactam antibiotics.

Molecular Detection of Tick-Borne Pathogens in American Bison (Bison bison) at El Uno Ecological Reserve, Janos, Chihuahua, Mexico.

American bison (Bison bison) is listed as near-threatened and in danger of extinction in Mexico. Recent studies have demonstrated the presence of several emerging pathogens at the Janos Biosphere Reserve (JBR), inhabited by one wild herd of American bison. Blood samples were collected from 26 American bison in the JBR. We tested for the presence of Anaplasma marginale, Babesia bigemina, B. bovis, Borrelia burgdorferi sensu lato, and Rickettsia rickettsii DNA using nested and semi-nested PCR protocols performing duplicates in two different laboratories. Results showed three animals (11.5%) positive for B. burgdorferi s. l., three more (11.5%) for Rickettsia rickettsii, and four (19.2%) for B. bovis. Two individuals were co-infected with B. burgdorferi s. l. and B. bovis. We found no animals positive for A. marginale and B. bigemina. This is the first report in America of R. rickettsii in American bison. American bison has been described as an important reservoir for pathogens of zoonotic and veterinary importance; thus, the presence of tick-borne pathogen DNA in the JBR American bison indicates the importance of continuous wildlife health surveys.

Mycobacterium bovis in a European bison (Bison bonasus) raises concerns about tuberculosis in Brazilian captive wildlife populations: a case report.

BACKGROUND: Tuberculosis caused by Mycobacterium bovis is an important worldwide zoonosis and has been reported to cause clinical disease in several animal species, including captive wildlife. This report describes a case of M. bovis infection in a European bison from a Brazilian zoo and compiles a number of literature reports that raise concern regarding tuberculosis among captive wildlife in Brazil. CASE PRESENTATION: A 13 year-old captive-born male bison (Bison bonasus) from a Brazilian zoo began presenting weight loss, diarrhea and respiratory symptoms, which inevitably led to his death. At the animal's necropsy, inspection of the thoracic and abdominal cavities revealed multiple enlarged lymph nodes, ranging from 4 to 10 cm, and pulmonary nodules containing caseous masses with firm white materials consistent with mineralization. Histopathology findings showed a significant amount of acid-alcohol resistant bacilli compatible with Mycobacterium spp. Specimens from lymph nodes and lungs were cultured on Petragnani and Stonebrink media, and specific PCR assays of the bacterial isolate identified it as M. bovis. CONCLUSION: The European bison reported herein died from a severe form of disseminated tuberculosis caused by M. bovis. A review of the available literature indicates possible widespread occurrence of clinical disease caused by M. bovis or M. tuberculosis affecting multiple animal species in Brazilian wildlife-related institutions. These likely underestimated numbers raise concern regarding the control of the disease in captive animal populations from Brazil.

Cryopreservation of bison epididymal sperm: A strategy for improving post-thaw quality when collecting sperm in field conditions.

This study was conducted to optimize the cryopreservation of epididymal bison sperm harvested in the field. In the first experiment, epididymal bison sperm were treated with or without seminal plasma (n = 6) and cooled to 5 °C over 2 hours. In a separate experiment, glycerol was added at different times and sperm was held at 5 °C for different periods of time before cryopreservation (n = 11). In addition, epididymal sperm frozen with and without seminal plasma (n = 6) and after 4, 24, and 48 hours (n = 5) of equilibration at 5 °C, were evaluated for their in vitro fertilizing ability. Post-thaw motility of bison epididymal sperm was similar when cryopreserved with or without seminal plasma or when glycerol was added at either 0, 4, 24, or 48 hours before freezing (P > 0.05). However, sperm incubated at 5 °C for 24 hours before freezing exhibited higher percentages of motile sperm (44% vs. 35% for 4 hours or 48 hours, P < 0.05). Fertilization rates of bison oocytes were not different for any treatments. Chilling the whole epididymis for 24 or 48 hours resulted in complete loss of sperm viability. In conclusion, bison epididymal sperm can be chilled outside of the epididymis for at least 48 hours before cryopreservation without compromising post-thaw sperm motility providing flexibility for technicians performing field collections.

Synergism of Cattle and Bison Inoculum on Ruminal Fermentation and Select Bacterial Communities in an Artificial Rumen (Rusitec) Fed a Barley Straw Based Diet.

This study evaluated the effect of increasing the proportion of bison relative to cattle inoculum on fermentation and microbial populations within an artificial rumen (Rusitec). The experiment was a completely randomized design with a factorial treatment structure (proportion cattle:bison inoculum; 0:100, 33:67, 67:33, and 100:0) replicated in two Rusitec apparatuses (n = 8 fermenters). The experiment was 15 d with 8 d of adaptation and 7 d of sampling. Fermenters were fed a diet of 70:30 barley straw:concentrate (DM basis). True digestibility of DM was determined after 48 h of incubation from d 13 to 15, and daily ammonia (NH3) and volatile fatty acid (VFA) production were measured on d 9-12. Protozoa counts were determined at d 9, 11, 13, and 15 and particle-associated bacteria (PAB) from d 13 to 15. Select bacterial populations in the PAB were measured using RT-qPCR. Fermenter was considered the experimental unit and day of sampling as a repeated measure. Increasing the proportion of bison inoculum resulted in a quadratic effect (P < 0.05) on straw, concentrate and total true DM disappearance and on straw and total neutral detergent fiber (aNDF) disappearance, with greater disappearances observed with mixed inoculum. There were no effect of source or proportion of inoculum on ADF disappearance (P > 0.05). Increasing bison inoculum linearly increased (P < 0.05) concentrate aNDF disappearance, total and concentrate N disappearance as well as total daily VFA and acetate production. A positive quadratic response (P < 0.05) was observed for daily NH3-N, propionate, butyrate, valerate, isovalerate and isobutyrate production, as well as the acetate:propionate ratio. Increasing the proportion of bison inoculum linearly increased (P < 0.05) total protozoa numbers. No effects were observed on pH, total gas and methane production, microbial N synthesis, or copies of 16S rRNA associated with total bacteria, Selenomonas ruminantium or Prevotella bryantii. Increasing bison inoculum had a quadratic effect (P < 0.05) on Fibrobacter succinogenes, and tended to linearly (P < 0.10) increase Ruminococcus flavefaciens and decrease (P < 0.05) Ruminococcus albus copy numbers. In conclusion, bison inoculum increased the degradation of feed protein and fiber. A mixture of cattle and bison rumen inoculum acted synergistically, increasing the DM and aNDF disappearance of barley straw.

Histology, histochemistry and fine structure of the Harderian gland, lacrimal gland and superficial gland of the third eyelid of the European bison, Bison bonasus bonasus (Artiodactyla: Bovidae)

The macroscopic anatomy and the microscopic and ultrastructural features of the Harderian gland (HG), lacrimal gland (LG) and superficial gland of the third eyelid (SGTE) of the adult European bison are described. In addition, morphometric studies were conducted and were followed by statistical analysis of the results. Tissue sections were stained with hematoxylin and eosin, methyl green-pyronin Y, periodic acid-Schiff, Alcian blue pH 2.5, aldehyde fuchsin and Hale's dialysed iron. Analysis of the staining showed that the HG has a multilobular tubuloalveolar structure with mixed secretion. The LG and the SGTE have a multilobar tubuloacinar structure with serous secretion in the LG and mucoserous in the SGTE. The TEM study demonstrates that the secretory cells of the HG, LG and SGTE have similar ultrastructural appearance, with two types of secretory vesicles in the cytoplasm of all studied glands. The histochemical staining methods and the TEM study revealed the secretory activity in the HG, LG and SGTE ducts. The structural studies can be important for establishing relations between morphological structure and functions of these glands. It can have clinical implications especially when taking into consideration the protective mechanisms of the eye.(AU)

Histology, histochemistry and fine structure of the Harderian gland, lacrimal gland and superficial gland of the third eyelid of the European bison, Bison bonasus bonasus (Artiodactyla: Bovidae)

The macroscopic anatomy and the microscopic and ultrastructural features of the Harderian gland (HG), lacrimal gland (LG) and superficial gland of the third eyelid (SGTE) of the adult European bison are described. In addition, morphometric studies were conducted and were followed by statistical analysis of the results. Tissue sections were stained with hematoxylin and eosin, methyl green-pyronin Y, periodic acid-Schiff, Alcian blue pH 2.5, aldehyde fuchsin and Hale's dialysed iron. Analysis of the staining showed that the HG has a multilobular tubuloalveolar structure with mixed secretion. The LG and the SGTE have a multilobar tubuloacinar structure with serous secretion in the LG and mucoserous in the SGTE. The TEM study demonstrates that the secretory cells of the HG, LG and SGTE have similar ultrastructural appearance, with two types of secretory vesicles in the cytoplasm of all studied glands. The histochemical staining methods and the TEM study revealed the secretory activity in the HG, LG and SGTE ducts. The structural studies can be important for establishing relations between morphological structure and functions of these glands. It can have clinical implications especially when taking into consideration the protective mechanisms of the eye.

First confirmed diagnosis of sheep-associated malignant catarrhal fever in bison in Argentina

In Argentina, cases of malignant catarrhal fever (MCF) are suspected to have occurred according to macro and microscopic lesions. However, none has been corroborated by molecular tests. We describe here the first laboratory confirmed case of MCF in Argentina occurring in American bison confined in the Buenos Aires Zoo.

First confirmed diagnosis of Sheep-associated Malignant Catarrhal Fever in Bison in Argentina

In Argentina, cases of malignant catarrhal fever (MCF) are suspected to have occurred according to macro and microscopic lesions. However, none has been corroborated by molecular tests. We describe here the first laboratory confirmed case of MCF in Argentina occurring in American bison confined in the Buenos Aires Zoo.(AU)