[Problems of ante mortem diagnostics of prion diseases].

The review presents the state-of-the-art on the problem of diagnosis of prion diseases (PD) in humans and animals with a brief description of their etiology and pathogenesis. We pointed out that understanding the nature of the etio logical agent of PD determined their zoonotic potential and led to the development of highly specific immunological diagnostic methods aimed at identifying the infectious isoform of prion protein (PrPd) as the only marker of the disease. In this regard, we briefly summarize the results of studies, including our own, concerning the conversion of normal prion protein molecules (PrPc) to PrPd, the production of monoclonal antibodies and their application as immunodiagnostic reagents for the post-mortem detection of PrPd in various formats of immunoassay.

Therapeutic administration of enrofloxacin in mice does not select for fluoroquinolone resistance in Campylobacter jejuni.

Enrofloxacin is registered for therapeutic use in beef cattle to treat bovine respiratory disease in Canada. A murine model was used to experimentally examine the impact of therapeutic administration of enrofloxacin on fluoroquinolone resistance development in Campylobacter jejuni. Administration of enrofloxacin to mice via subcutaneous injection or per os routes resulted in equivalent levels of bioactive enrofloxacin within the intestine, but bioactivity was short-lived (<48 h after cessation).

Monomorphic genotypes within a generalist lineage of show signs of global dispersion.

The decreased costs of genome sequencing have increased the capability to apply whole-genome sequencing to epidemiological surveillance of zoonotic However, knowledge of the genetic diversity of this bacteria is vital for inferring relatedness between epidemiologically linked isolates and a necessary prerequisite for correct application of this methodology. To address this issue in we investigated the spatial and temporal signals in the genomes of a major clonal complex and generalist lineage, ST-45 CC, by analysing the population structure and genealogy as well as applying genome-wide association analysis of 340 isolates from across Europe collected over a wide time range. The occurrence and strength of the geographical signal varied between sublineages and followed the clonal frame when present, while no evidence of a temporal signal was found.

Whole-Genome Sequencing in Epidemiology of Campylobacter jejuni Infections.

This review describes the current state of knowledge regarding the application of whole-genome sequencing (WGS) in the epidemiology of , the leading cause of bacterial gastroenteritis worldwide. We describe how WGS has increased our understanding of the evolutionary and epidemiological dynamics of this pathogen and how WGS has the potential to improve surveillance and outbreak detection. We have identified hurdles to the full implementation of WGS in public health settings.

Biosafety in embryos and semen cryopreservation, storage, management and transport.

This chapter summarizes pertinent procedures, data and opinions on the potential hazards of disease transmission through liquid nitrogen (LN)-cryopreserved and banked germplasm and tissues for somatic cell nuclear transfer (SCNT) The importance of applying internationally adopted sanitary washing procedures to germplasm as a crucial step towards their successful microbial-free cryopreservation and storage is emphasised. Special attention is given to the survival of pathogens in LN, variety of vitrification methods, sterility of LN, risks associated with the use of straws and cryovials, and LN Dewars including dry shippers. It was experimentally demonstrated that cross-contamination between LN and embryos may occur, when infectious agents are present in LN and if embryos are not protected by use of a sealed container.

Effect of cryopreservation by slow cooling and vitrification on viral contamination of IVF embryos experimentally exposed to bovine viral diarrhea virus and bovine herpesvirus-1.

The objective was to determine the effect of cryopreservation by conventional slow controlled cooling (0.5 degrees C/min) and by vitrification on the presence of bovine viral diarrhea virus (BVDV) and bovine herpesvirus-1 (BHV-1) infectivity associated with frozen-thawed Day 7 bovine embryos. In this study, Day 7 embryos generated by in vitro fertilization (IVF) were exposed in vitro for 1.

Risk of contamination of germplasm during cryopreservation and cryobanking in IVF units.

Cryopreservation of sperm, embryos and, more recently, oocytes plays an important and increasing role in assisted reproduction, due to improvements of old, and introduction of new technologies. In parallel, concerns are increasing about the technical and biological safety of these procedures. However, published data regarding the confirmed or theoretical hazards of these procedures are sparse and sometimes contradictory.

Transmission of bovine viral diarrhea virus (BVDV) via in vitro-fertilized embryos to recipients, but not to their offspring.

The objective was to assess the potential of Day-7, IVP zona pellucida-intact blastocysts to transmit bovine viral diarrhea virus (BVDV) to embryo recipients. Embryos were exposed (1h) to two non-cytopathic (NCP) biotypes, either NY-1 (type 1) or two concentrations of PA-131 (type 2), washed 10 times, and transferred into recipients (two embryos/recipient) free of BVDV and its antibody. Six (30.

Comparative genomic assessment of Multi-Locus Sequence Typing: rapid accumulation of genomic heterogeneity among clonal isolates of Campylobacter jejuni.

Background: Multi-Locus Sequence Typing (MLST) has emerged as a leading molecular typing method owing to its high ability to discriminate among bacterial isolates, the relative ease with which data acquisition and analysis can be standardized, and the high portability of the resulting sequence data. While MLST has been successfully applied to the study of the population structure for a number of different bacterial species, it has also provided compelling evidence for high rates of recombination in some species. We have analyzed a set of Campylobacter jejuni strains using MLST and Comparative Genomic Hybridization (CGH) on a full-genome microarray in order to determine whether recombination and high levels of genomic mosaicism adversely affect the inference of strain relationships based on the analysis of a restricted number of genetic loci.

A novel cell wall-anchored peptidoglycan hydrolase (autolysin), IspC, essential for Listeria monocytogenes virulence: genetic and proteomic analysis.

We have recently concluded that a Listeria monocytogenes 86 kDa immunogenic surface protein, IspC, is a cell wall-anchored peptidoglycan hydrolase (autolysin), capable of degrading the cell wall peptidoglycan of the bacterium itself. To determine if this enzyme has any biological functions and/or plays a role in virulence, we in-frame-deleted the ispC gene from the L. monocytogenes chromosome.

Competitive exclusion of Salmonella typhimurium in broilers fed with vermicompost and complex carbohydrates.

Vermicompost (VC) was produced by earthworms fed with fresh chicken faeces, and was earth-like in appearance and odour. In three experiments, VC was sprinkled on the first feed of newly-hatched broiler chicks. Treated and control groups were challenged on day 6 by the addition of seeder chicks that had been inoculated orally with Salmonella typhimurium.

InlA and InlC2 of Listeria monocytogenes serotype 4b are two internalin proteins eliciting humoral immune responses common to listerial infection of various host species.

The internalins InlA and InlC2 are encoded proteins from two strongly immunoreactive clones recently identified by differential immunoscreening of a Listeria monocytogenes serotype 4b genomic expression library during the search of the gene products of L. monocytogenes specifically induced in vivo during infection (Yu WL, Dan H, Lin M. J Med Microbiol 56:888-895, 2007).

DNA prime protein boost strategies protect cattle from bovine viral diarrhea virus type 2 challenge.

At present, infections with bovine viral diarrhea virus (BVDV) type 2 occur nearly as frequently as those with BVDV type 1, so development of vaccines that protect cattle from both type 1 and type 2 BVDV has become critical. In this study, we compared various DNA prime-protein boost vaccination strategies to protect cattle from challenge with BVDV-2 using the major protective antigen of BVDV, glycoprotein E2. Calves were immunized with a plasmid encoding either type 1 E2 (E2.

Evidence for virus closely related to avian myeloblastosis-associated virus type 1 in a commercial stock of chickens.

A two-round nested polymerase chain reaction assay detected Rous associated virus-1 (RAV-1), a prototype laboratory strain of avian leukosis virus of subgroup A (ALV-A). Surprisingly, the test failed to detect three field isolates of ALV-A but did detect virus in one commercial stock of chickens (stock F). The sequence analysis of a core of 290 nucleotides of the env gene gave evidence that the virus from stock F was closely related to avian myeloblastosis-associated virus type one (MAV-1).

Novel protein targets of the humoral immune response to Listeria monocytogenes infection in rabbits.

The role of the humoral immune response in protective immunity against listerial infection has been overlooked and is essentially unknown. This study aimed to discover the protein targets of Listeria monocytogenes that elicit an antibody response following infection in a rabbit model. A genomic expression library for L.

Disinfection procedures for controlling microorganisms in the semen and embryos of humans and farm animals.

Semen and embryos generated by assisted reproductive techniques (ARTs) may be contaminated with numerous microorganisms. Contamination may arise from systemic or local reproductive tract infections in donors or the inadvertent introduction of microorganisms during ARTs, and may lead to disease transmission. This review describes sanitary procedures which have been investigated to ascertain whether they are effective in rendering semen and embryos free of pathogenic microorganisms, including internationally adopted washing procedures, which can be supplemented by antibiotics and enzymatic treatments.

Binding of bovine prion protein to heparin: a fluorescence polarization study.

Glycosaminoglycans (GAGs) are believed to be associated with prion disease pathology and also with metabolism of the prion protein. Fluorescence polarization assay (FPA) of binding between bovine recombinant prion protein (brecPrP) and heparin labelled with AlexaFluor488 was used in model experiments to study glycosaminoglycan-prion protein interaction. Heparin binding to brecPrP was a rapid reversible event which occurred under defined conditions.

A novel surface autolysin of Listeria monocytogenes serotype 4b, IspC, contains a 23-residue N-terminal signal peptide being processed in E. coli.

The 86-kDa protein IspC of 774 amino acids in Listeria monocytogenes serotype 4b has been recently identified as the target of humoral immune response to listerial infection and as a novel surface autolysin. A signal peptide is predicted at the N-terminal end of IspC, but no biochemical data has been shown to confirm the presence of the cleavage site of a signal peptidase. To address this and prepare sufficient amount of the protein for biochemical and structural characterization, we present a strategy for efficient expression and purification of IspC and analyze the purified protein by N-terminal sequencing and mass spectrometry.

Evidence for degradation of abnormal prion protein in tissues from sheep with scrapie during composting.

This study investigated whether the abnormal prion protein (PrP(Sc)) in tissues from sheep with scrapie would be destroyed by composting. Tissues from sheep naturally infected with scrapie were placed within fiberglass mesh bags and buried in compost piles for 108 d in experiment 1 or 148 d in experiment 2. The temperature in the compost piles rose quickly; it was above 60 degrees C for about 2 wk and then slowly declined to the ambient temperature.

Identification of IspC, an 86-kilodalton protein target of humoral immune response to infection with Listeria monocytogenes serotype 4b, as a novel surface autolysin.

We identified and biochemically characterized a novel surface-localized autolysin from Listeria monocytogenes serotype 4b, an 86-kDa protein consisting of 774 amino acids and known from our previous studies as the target (designated IspC) of the humoral immune response to listerial infection. Recombinant IspC, expressed in Escherichia coli, was purified and used to raise specific rabbit polyclonal antibodies for protein characterization. The native IspC was detected in all growth phases at a relatively stable low level during a 22-h in vitro culture, although its gene was transiently transcribed only in the early exponential growth phase.

Estimated direct economic costs associated with tick-borne diseases on cattle in Tanzania.

Tick-borne diseases, namely, anaplasmosis, babesiosis, cowdriosis and theileriosis, constrain cattle production and improvement in Tanzania, leading to considerable economic losses. A simple spreadsheet model was used to estimate the economic losses resulting from production losses, treatment and control costs associated with tick-borne diseases (TBD) in Tanzania. Model parameters included the national cattle population, reported TBD morbidity, fatality risk, and chemotherapy and control measures used.

Treatment of plague: promising alternatives to antibiotics.

Plague still poses a significant threat to human health, and interest has been renewed recently in the possible use of Yersinia pestis as a biological weapon by terrorists. The septicaemic and pneumonic forms are always lethal if untreated. Attempts to treat this deadly disease date back to the era of global pandemics, when various methods were explored.

Evaluation of the hygienic quality and associated public health hazards of raw milk marketed by smallholder dairy producers in the Dar es Salaam region, Tanzania.

A cross-sectional study was conducted to determine three parameters of the quality of the raw milk marketed by milk selling points (MSPs) in Dar es Salaam region. Total bacterial count (TBC) was used as an indicator of the microbial quality of the milk; antimicrobial residues were determined; and the California mastitis test (CMT) was used to screen for milk somatic cells as an indication of the mastitis level in the cows that provided the milk. Moreover, a water sample at each MSP was taken for bacteriological culturing.

A microsphere immunoassay for detection of antibodies to avian influenza virus.

A microsphere immunoassay (MIA) was developed for the detection of serum antibodies to avian influenza virus. A recombinant influenza A nucleoprotein expressed in baculovirus was conjugated to microspheres and incubated with antibodies. High median fluorescent intensities (MFIs) were obtained with a monoclonal antibody and positive chicken sera.