Theiler's virus-induced demyelination represents an important animal model to study the chronic-progressive form of multiple sclerosis (MS). The aim of the present study was to identify specific genes and pathways in the deep cervical lymph node (cLN) and spleen of experimentally infected SJL-mice, using DNA microarrays. Analyses identified 387 genes in the deep cLN and only 6 genes in the spleen of infected animals. The lymph node presented 27.4% of genes with fold changes +/-1.5 at 14 days post infection (dpi) and a reduced transcription at later time points. K-means clustering analyses resulted in five clusters. Accordingly, functional annotation revealed that the B-cell immune response pathway was the most up-regulated cluster at the early phase. Additionally, an increase of CD68- and lysozyme-positive cells in the deep cLN was observed by immunohistochemistry. Polioencephalitis was most intense at 14 dpi, and the spinal cord demyelinating leukomyelitis started at 42 dpi. In summary, early gene expression is indicative of virus-trigged immune responses in the central nervous system (CNS)-draining lymph node. The decreased gene transcription in the deep cLN during the chronic phase and the low number of spleen genes supports the hypothesis of a compartmentalized inflammation within the CNS, as described in progressive MS.
IntroductionE. coli is a ubiquitous bacterium commonly used as a sentinel in antimicrobial resistance studies. Here, E. coli was isolated from three groups (sick calves, healthy calves and bedding material), to assess the presence of antimicrobial resistance, describe resistance profiles, and compare these resistances among groups.Material and methodsSamples were collected from calves and calving pens from 20 dairy farms. Using the disc diffusion method, E. coli isolates were screened for antimicrobial resistance against seven antimicrobials: Amoxicillin, Ceftiofur, Gentamicin, Enrofloxacin, Trimethoprim–sulfamethoxazole, Florfenicol and Oxytetracycline. Isolates resistant to all these seven antimicrobials were tested again against an extended 19 antimicrobial drug panel and for the presence of the most common E. coli pathogenicity genes through PCR.Results & discussionThree hundred forty-nine E. coli isolates were obtained; most isolates were resistant to a single antimicrobial, but 2.3% (8) were resistant to 16 to 19 of the antimicrobials tested. The group with the highest percentage of multiresistant isolates was the calves with diarrhea group. Younger calves provided samples with higher antimicrobial resistance levels.ConclusionsThere is a high rate of antimicrobial resistance in dairy farms calving pens. These bacteria could not only be a resistance gene reservoir, but also could have the potential to spread these determinants through horizontal gene transfer to other susceptible bacteria. Measures should be taken to protect colonization of younger calves, based on hygienic measures and proper management.
SUMMARYMycobacterium avium subsp. paratuberculosis (Map) is the etiological agent of paratuberculosis. In Chile, information about Map isolation from both domestic ruminant and wildlife species has been accumulating, but it has extended to other species. In Chile, deer farming activity has been focused in hunting and meat production. No paratuberculosis surveillance has been reported for these source herds. In the present study, chronic diarrhea and poor body condition in some animals belonging to a deer farm was informed. Four adult affected hinds were euthanized under suspicion of paratuberculosis. In all animals macroscopic and microscopic lesions consistent with paratuberculosis were observed. Map-positive culture results from faecal and tissue samples, complemented with positive-PCR-results from fixed tissues are informed. Evidence has been found on cattle and deer populations being connected since molecular characterization of the Map isolated from deer lack of variation between the cattle control strain. The latter could indicate that both species share the same bacteria, suggesting there is interspecies transmission. Complementary diagnostic methods were accurate to diagnose paratuberculosis and to differentiate the clinical deer case from other mycobacterial infection. The epidemiological findings suggest that the infection in the deer farm could be transmitted from a cattle herd, making this the first reported case of paratuberculosis in deer farm in Chile.Key words: deer, histopathology, paratuberculosis, PCR. RESUMENMycobacterium avium subsp. paratuberculosis (Map) es el agente etiológico de la patuberculosis. En Chile, antecedentes del aislamiento de Map tanto en rumiantes domésticos como en especies de vida silvestre se han ido acumulando a través del tiempo, sin embargo, esto tiene que estar afectando también a otras especies. En Chile, la crianza de ciervos se ha focalizado en dos objetivos: cotos de caza y producción de carnes exóticas, no existiendo un programa de vigilancia ni siendo reportada esta enfermedad en rebaños de este tipo. Este trabajo reporta la presencia de diarrea crónica y pobre condición corporal en algunos animales pertenecientes a una granja de ciervos donde se sospechó la presencia de paratuberculosis. Cuatro ciervos adultos fueron eutanaziados bajo esta sospecha. Todos los animales presentaron lesiones macro y microscópicas compatibles con paratuberculosis. Resultados positivos al cultivo bacteriológico a partir de heces y muestras de tejido, además de PCR a partir de tejido fijado evidencian la infección. De acuerdo a los resultados de caracterización molecular de las cepas aisladas de los ciervos que no muestran variación entre cepas control de bovino, se evidencia que ambas poblaciones estarían conectadas. Complementariamente, los métodos diagnósticos utilizados fueron muy precisos para diagnosticar paratuberculosis y para diferenciar casos clínicos en ciervos de otras micobacteriosis. Las características epidemiológicas descritas en este estudio sugieren que la infecció...
Paratuberculosis is a disease caused by Mycobacterium avium subsp. paratuberculosis (MAP) that affects domestic and wild ruminants. The most common gross lesions are emaciation and corrugation and thickening of the mucosa of the small intestine. Mesenteric lymph nodes might be enlarged. For the present study, 14 red deer and 9 fallow deer from game reserves or venison farms were analyzed. The lesions found correspond to those found by other authors in other geographic locations, except for some differences in histopathological examinations. Among these differences, stands out that intestinal lesions were concentrated mostly in the ileum and granulomas were shown to be more frequent in this section of the intestine than in the corresponding lymph node. Furthermore, in multibacillary lesions the inflammatory infiltrate in the lymph nodes was mainly composed of macrophages. These differences may be due to individual variations of the animals, the stage of disease or a different strain of the pathogen. This study allowed to obtain basic information about the disease and to describe patterns of lesions found in red deer and fallow deer with prediagnosis of clinical paratuberculosis which were not described in the literature before.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.