Quali-quantitative evaluation of ileal peyer's patches innervation in scrapie-free or scrapie-affected sarda breed ovines

Although Peyer's patches (PPs) and the enteric nervous system (ENS) play a key role in early sheep scrapie pathogenesis, little is known on the kinetics of ENS plexuses colonization. This study was aimed at quali-quantitatively evaluating ileal PP innervation in 29 Sarda breed ovines (12 scrapie-free, 2 months-old lambs, 4 ARQ/ARQ, 4 ARR/ARQ and 4 ARR/ARR, respectively; 12 scrapie-free, 2-4 years-old sheep, 3 ARQ/ARQ, 7 ARR/ARQ and 2 ARR/ARR, respectively; 5 ARQ/ARQ scrapie-affected sheep)

Cellular Prion Protein Expression in the Brain Tissue from Brucella ceti-Infected Striped Dolphins (Stenella coeruleoalba)

Brucella ceti, a zoonotic pathogen of major concern to cetacean health and conservation, is responsible for severe meningo-encephalitic/myelitic lesions in striped dolphins (Stenella coeruleoalba), often leading to their stranding and death. This study investigated, for the first time, the cellular prion protein (PrPc) expression in the brain tissue from B. ceti-infected, neurobrucellosis-affected striped dolphins. Seven B. ceti-infected, neurobrucellosis-affected striped dolphins, found stranded along the Italian coastline (6) and in the Canary Islands (1), were investigated, along with five B. ceti-uninfected striped dolphins from the coast of Italy, carrying no brain lesions, which served as negative controls. Western Blot (WB) and immunohistochemistry (IHC) with an anti-PrP murine monoclonal antibody were carried out on the brain parenchyma of these dolphins. While PrPc IHC yielded inconclusive results, a clear-cut PrPc expression of different intensity was found by means of WB analyses in the brain tissue of all the seven herein investigated, B. ceti-infected and neurobrucellosis-affected cetacean specimens, with two dolphins stranded along the Italian coastline and one dolphin beached in Canary Islands also exhibiting a statistically significant increase in cerebral PrPc expression as compared to the five Brucella spp.-negative control specimens. The significantly increased PrPc expression found in three out of seven B. ceti-infected, neurobrucellosis-affected striped dolphins does not allow us to draw any firm conclusion(s) about the putative role of PrPc as a host cell receptor for B. ceti. Should this be the case, an upregulation of PrPc mRNA in the brain tissue of neurobrucellosis-affected striped dolphins could be hypothesized during the different stages of B. ceti infection, as previously shown in murine bone marrow cells challenged with Escherichia coli. Noteworthy, the inflammatory infiltrates seen in the brain and in the cervico-thoracic spinal cord segments from the herein investigated, B. ceti-infected and neurobrucellosis-affected striped dolphins were densely populated by macrophage/histiocyte cells, often harboring Brucella spp. antigen in their cytoplasm, similarly to what was reported in macrophages from mice experimentally challenged with B. abortus. Notwithstanding the above, much more work is needed in order to properly assess the role of PrPc, if any, as a host cell receptor for B. ceti in striped dolphins

Immunohistochemical investigations on Brucella ceti-infected, neurobrucellosis-affected striped dolphins (Stenella coeruleoalba)

Bacteria of the genus Brucella cause brucellosis, an infectious disease common to humans as well as to terrestrial and aquatic mammals. Since 1994 several cases of Brucella spp. infection have been reported in marine mammals worldwide. Indeed, since human brucellosis ranks as one of the most common bacterial zoonotic infections on a global scale, it is necessary to increase our knowledge about it also in the marine environment. Brucella ceti, which is phenotypically similar to other smooth brucellae as B. abortus and B. melitensis, shares with the latter two the same surface antigens that are routinely used for the serological diagnosis of Brucella spp. infection. Marine mammal Brucella spp. infections are characterized by a pathogenicity similar to their terrestrial counterparts, with the occurrence of abortion, stillbirth and orchitis and an involvement of the host’s central nervous system (CNS), similarly to what happens in mankind. While sero-epidemiological data suggest that Brucella spp. infection is widespread globally, detecting Brucella spp.-associated antigens by immunohistochemistry (IHC) in tissues from infected animals is often troublesome. The present study was aimed at investigating, by means of IHC based upon the utilization of an anti-Brucella LPS monoclonal antibody (MAb), the CNS immunoreactivity (IR) shown by B. ceti-infected, neurobrucellosis-affected striped dolphins