Bovine tuberculosis in Europe from the perspective of an officially tuberculosis free country: trade, surveillance and diagnostics.

Switzerland has been officially free of bovine tuberculosis (OTF) since 1960. Since 1980 the control of bovine tuberculosis (bTB) has been reduced to passive abattoir surveillance. Isolated cases of bTB, partly due to reactivation of human Mycobacterium bovis infections with subsequent transmission to cattle, have been noticed in the last years.

Bovine tuberculosis: effect of the tuberculin skin test on in vitro interferon gamma responses.

Bovine tuberculosis (bTB) is a disease of zoonotic and economic importance. In many countries, control is based on test and slaughter policies and/or abattoir surveillance. For testing, cell mediated immune- (CMI-) based assays (i.

Bayesian receiver operating characteristic estimation of multiple tests for diagnosis of bovine tuberculosis in Chadian cattle.

Background: Bovine tuberculosis (BTB) today primarily affects developing countries. In Africa, the disease is present essentially on the whole continent; however, little accurate information on its distribution and prevalence is available. Also, attempts to evaluate diagnostic tests for BTB in naturally infected cattle are scarce and mostly complicated by the absence of knowledge of the true disease status of the tested animals.

Assessment of Mycobacterium tuberculosis OmpATb as a novel antigen for the diagnosis of bovine tuberculosis.

In the search for better tools to control bovine tuberculosis, the development of diagnostic tests with improved specificity and sensitivity has a high priority. We chose to search for novel immunodiagnostic reagents. In this study, Rv0899 (outer membrane protein A of Mycobacterium tuberculosis [OmpATb]) was evaluated as a stimulation antigen in a gamma interferon (IFN-gamma) release assay to diagnose bovine tuberculosis.

Optimization of a whole-blood gamma interferon assay for detection of Mycobacterium bovis-infected cattle.

Antigens of Mycobacterium bovis elicit a cell-mediated immune response upon intradermal injection in cattle. In vitro, such antigens stimulate the production of gamma interferon (IFN-gamma) by bovine T cells in whole-blood culture (IFN-gamma assay). We have analyzed various parameters of the in vitro IFN-gamma assay, ranging from blood sampling to execution of the IFN-gamma test, in view of potential simplifications of the assay.

Comparative assessment of fluorescence polarization and tuberculin skin testing for the diagnosis of bovine tuberculosis in Chadian cattle.

Effective surveillance of bovine tuberculosis (BTB) in developing countries where reliable data on disease prevalence is scarce or absent is a precondition for considering potential control options. We conducted a slaughterhouse survey to assess for the first time the burden of BTB in Southern Chad. Altogether, 954 slaughter animals were consecutively sampled and tested using the single intra-dermal comparative cervical tuberculin (SICCT) test, a recently developed fluorescence polarization assay (FPA) and routine abattoir meat inspection after slaughter.

The prion protein is neuroprotective against retinal degeneration in vivo.

A common feature of neurodegenerative disorders is acute or progressive loss of neurons due to apoptosis. The pathological isoform of the prion protein is associated with retinal apoptosis and the cellular isoform (PrPc) has been shown to mediate protection from apoptosis in cell culture and in neonatal retinal explants. Using a model of light-induced photoreceptor apoptosis, we show in vivo that the levels of PrPc expression in the retina inversely correlate with the susceptibility of photoreceptors to light damage.

Comparison of immunohistochemistry and two rapid tests for detection of abnormal prion protein in different brain regions of sheep with typical scrapie.

One of the "gold standard" techniques for postmortem confirmation of scrapie diagnosis in sheep and goats is immunohistochemical examination of brain tissue. Active surveillance for scrapie is mainly performed by rapid diagnostic tests on the basis of postmortem immunochemical detection of prion protein (PrP) in the obex tissue. The aim of this study was to determine the performance of 2 rapid tests, Prionics-Check LIA (a chemiluminescence sandwich enzyme-linked immunosorbent assay) and Prionics-Check Western blot for scrapie diagnosis when applied to brain areas other than the obex, in comparison with the recognized immunohistochemistry.

Immunodetection of disease-associated mutant PrP, which accelerates disease in GSS transgenic mice.

The absence of infectivity-associated, protease-resistant prion protein (PrP(Sc)) in the brains of spontaneously sick transgenic (Tg) mice overexpressing PrP linked to Gerstmann-Sträussler Scheinker syndrome, and the failure of gene-targeted mice expressing such PrP to develop disease spontaneously, challenged the concept that mutant PrP expression led to spontaneous prion production. Here, we demonstrate that disease in overexpressor Tg mice is associated with accumulation of protease-sensitive aggregates of mutant PrP that can be immunoprecipitated by the PrP(Sc)-specific monoclonal antibody designated 15B3. Whereas Tg mice expressing multiple transgenes exhibited accelerated disease when inoculated with disease-associated mutant PrP, Tg mice expressing mutant PrP at low levels failed to develop disease either spontaneously or following inoculation.

Aggravation of ischemic brain injury by prion protein deficiency: role of ERK-1/-2 and STAT-1.

The cellular isoform of prion protein, PrPc, may confer neuroprotection in the brain, according to recent studies. To elucidate the role of PrPc in stroke pathology, we subjected PrPc-knockout (Prnp(0/0)), wild-type and PrPc-transgenic (tga20) mice to 30 min of intraluminal middle cerebral artery occlusion, followed by 3, 24 or 72 h reperfusion, and examined how PrPc levels influence brain injury and cell signaling. In immunohistochemical experiments and Western blots, we show that PrPc expression is absent in the brains of Prnp(0/0) mice, detectable in wild-type controls and approximately 4.

Diagnosis of prion diseases.

Prion diseases are usually diagnosed clinically and confirmed by post-mortem histopathological examination of brain tissue. The only reliable molecular marker for prion diseases is PrP(Sc), the pathological conformer of the prion protein that accumulates in the central nervous system and, to a lesser extent, in lymphoreticular tissues. For BSE, several commercial diagnostic kits based on the post-mortem immunochemical detection of PrP(Sc) in brain tissue are now available.

PrP(CWD) lymphoid cell targets in early and advanced chronic wasting disease of mule deer.

Up to 15% of free-ranging mule deer in northeastern Colorado and southeastern Wyoming, USA, are afflicted with a prion disease, or transmissible spongiform encephalopathy (TSE), known as chronic wasting disease (CWD). CWD is similar to a subset of TSEs including scrapie and variant Creutzfeldt-Jakob disease in which the abnormal prion protein isoform, PrP(CWD), accumulates in lymphoid tissue. Experimental scrapie studies have indicated that this early lymphoid phase is an important constituent of prion replication interposed between mucosal entry and central nervous system accumulation.

Prion protein interaction with glycosaminoglycan occurs with the formation of oligomeric complexes stabilized by Cu(II) bridges.

Several lines of evidence have shown glycosaminoglycans (GAGs) to be physiological ligands of the prion protein (PrP), but the molecular and regulatory aspects of the interaction remain unknown. Using full-length recombinant prion protein and low molecular mass heparin and heparan sulfate as glycosaminoglycans, we have found that the interaction occurs with the formation of oligomeric complexes. Within the protein-glycosaminoglycan complexes, PrP exhibited an enhanced fluorescence emission and a reduced solvent exposure.

Validation of a luminescence immunoassay for the detection of PrP(Sc) in brain homogenate.

A luminescence immunoassay (LIA) was developed for the diagnosis of bovine spongiform encephalopathy (BSE) in brain tissue using two different monoclonal antibodies for capture and detection of the protease-resistant fragment of the pathological prion protein (PrP27-30). PrP27-30 currently represents the most reliable marker for the infectious particle (denominated prion) causing transmissible spongiform encephalopathies (TSEs). Internal and official validation studies of this assay are described using brain homogenates from ascertained BSE positive and negative cows.

PrP(CWD) in the myenteric plexus, vagosympathetic trunk and endocrine glands of deer with chronic wasting disease.

Accumulated evidence in experimental and natural prion disease systems supports a neural route of infectious prion spread from peripheral sites of entry to the central nervous system. However, little is known about prion trafficking routes in cervids with a naturally occurring prion disease known as chronic wasting disease (CWD). In the brain, the pathogenic isoform of the prion protein (PrP(CWD)) accumulates initially in the dorsal motor nucleus of the vagus nerve.