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PubMed2005

Genetic diversity of Listeria monocytogenes strains from a high-prevalence dairy farm.

Listeria monocytogenes is a significant food-borne human and veterinary pathogen. Contaminated silage commonly leads to disease in livestock, but the pervasive nature of the bacterium can make it difficult to identify the source of infection. An investigation of bovine listeriosis that occurred on a Pacific Northwest dairy farm ("farm A") revealed that the clinical strain was closely related to fecal strains from asymptomatic cows, and that farm environment was heavily contaminated with a diversity of L. monocytogenes strains. In addition, the farm A clinical strain was closely related to clinical and environmental strains obtained 1 year prior from a second Northwest dairy farm ("farm B"). To investigate the source(s) of contamination on farm A, environmental samples were collected from farm A at two time points. Pulsed-field gel electrophoresis characterization of 538 isolates obtained from that farm identified 57 different AscI pulsovars. Fecal isolates obtained from individual cows were the most genetically diverse, with up to 94% of fecal samples containing more than one pulsovar. The maximum numbers of pulsovars and serotypes isolated from a fecal sample of one cow were 6 and 4, respectively. Serotype 1/2a was isolated most frequently at both time points. Microarray genotyping of bovine listeriosis, fecal, and silage strains from both farms identified four probes that differentiated listeriosis strains from environmental strains; however, no probe was common to both bovine listeriosis strains.

Animals↗
PubMed1999

Clinical Microbiology Reviews: genesis of a journal.

In 1986 planning for a new ASM review journal, Clinical Microbiology Reviews (CMR), began. CMR would publish articles primarily of interest to persons concerned with pathogenesis, laboratory diagnosis, epidemiology, and control of human and veterinary pathogens. The first issue was published in January 1988, with quarterly publication since then. The journal quickly became successful in terms of subscribers and impact on the field, earning a strong national and international reputation. The achievements of CMR are owed to many persons, including the editorial board, the production team, and especially the contributing authors.

Humans↗
PubMed1983

Detection of antigenically distinct rotaviruses from infants.

Antigenically distinct rotaviruses, i.e., viruses morphologically identical to conventional rotaviruses by electron microscopy, yet lacking the common group antigen(s) detected by an enzyme-linked immunosorbent assay, were found in 2 of 51 fecal samples from Bulgarian infants with rotavirus gastroenteritis. These antigenically distinct viruses contained 11 segments of double-stranded RNA, but they demonstrated a unique RNA migration profile after electrophoresis of the genome RNA in polyacrylamide gels. This report confirms the presence of a new group of rotaviruses in humans. The significance of these viruses is currently unknown, and specific diagnostic tests must be developed for epidemiological studies to determine their role as human and veterinary pathogens and to evaluate their impact on proposed vaccine development programs.

Antigens, Viral↗
PubMed1999

Immunological characterization of a protective antigen of Erysipelothrix rhusiopathiae: identification of the region responsible for protective immunity.

The gene encoding a protective protein antigen of the gram-positive bacterium Erysipelothrix rhusiopathiae, an important veterinary pathogen responsible for erysipelas in swine and a variety of diseases in animals, was cloned and sequenced. The gene encodes a polypeptide of 597 amino acids plus a putative signal sequence of 29 amino acids, resulting in a mature protein with a molecular mass of 69,017 Da. Sequence analysis of the gene product revealed a C-terminal region composed of nine tandem repeats of 20 amino acids and a total sequence that is nearly identical to that of the 64-kDa cell surface protein (SpaA) of the bacterium. Because of this similarity, the protein was designated SpaA.1. In this study, we examined whether the SpaA.1 protein could induce protective antibodies and whether we could identify the region involved in protective immunity. Both the mature SpaA.1 protein and its C-terminal repeat region, but not the N-terminal segment, were expressed in Escherichia coli and purified as a histidine-tagged fusion recombinant protein. Rabbit antiserum raised against the mature SpaA.1 protein passively protected mice from lethal challenge with a virulent homologous strain, Fujisawa-SmR, suggesting that protection is mediated by humoral antibodies. To determine which domain of the SpaA.1 protein is responsible for the observed protection, mice were actively immunized with either the mature SpaA. 1 protein or the C-terminal repeat region and then challenged with Fujisawa-SmR. The result showed that mice immunized with the mature SpaA.1 protein, but not the C-terminal repeat region, were protected, suggesting that the protection-eliciting epitope(s) is located within the N-terminal two-thirds of the SpaA.1 molecule. This was confirmed by passive immunization experiments in which the protective activity of rabbit antiserum, raised against mature SpaA. 1 protein, was not abolished by absorption with the purified recombinant C-terminal repeat region. In addition, antibodies specific for the C-terminal repeat region were unable to protect mice from lethal challenge. These results show that the N-terminal two-thirds of the SpaA.1 molecule may constitute a good vaccine candidate against erysipelas.

Animals↗
PubMed2004

Tritrichomonas foetus induces apoptotic cell death in bovine vaginal epithelial cells.

Tritrichomonas foetus is a serious veterinary pathogen, causing bovine trichomoniasis, a sexually transmitted disease leading to infertility and abortion. T. foetus infects the mucosal surfaces of the reproductive tract. Infection with T. foetus leads to apoptotic cell death of bovine vaginal epithelial cells (BVECs) in culture. An affinity-purified cysteine protease (CP) fraction yielding on sodium dodecyl sulfate-polyacrylamide gel electrophoresis a single band with an apparent molecular mass of 30 kDa (CP30) also induces BVEC apoptosis. Treatment of CP30 with the protease inhibitors TLCK (Nalpha-p-tosyl-l-lysine chloromethyl ketone) and E-64 [l-trans-epoxysuccinyl-leucylamide-(4-guanido)-butane] greatly reduces induction of BVEC apoptosis. Matrix-assisted laser desorption ionization-time-of-flight MALDI-TOF mass spectrometry analysis of CP30 reveals a single peak with a molecular mass of 23.7 kDa. Mass spectral peptide sequence analysis of proteolytically digested CP30 reveals homologies to a previously reported cDNA clone, CP8 (D. J. Mallinson, J. Livingstone, K. M. Appleton, S. J. Lees, G. H. Coombs, and M. J. North, Microbiology 141:3077-3085, 1995). Induction of apoptosis is highly species specific, since the related human parasite Trichomonas vaginalis and associated purified CPs did not induce BVEC death. Fluorescence microscopy along with the Cell Death Detection ELISA(PLUS) assay and flow cytometry analyses were used to detect apoptotic nuclear condensation, DNA fragmentation, and changes in plasma membrane asymmetry in host cells undergoing apoptosis in response to T. foetus infection or incubation with CP30. Additionally, the activation of caspase-3 and inhibition of cell death by caspase inhibitors indicates that caspases are involved in BVEC apoptosis. These results imply that apoptosis is involved in the pathogenesis of T. foetus infection in vivo, which may have important implications for therapeutic interference with host cell death that could alter the course of the pathology in vivo.

Animals↗
PubMed1995

Serologic cross-reactions among Ehrlichia equi, Ehrlichia phagocytophila, and human granulocytic Ehrlichia.

Homology in the 16S rDNAs shows that the agent of human granulocytic ehrlichiosis (HGE) is closely related to the veterinary pathogens Erlichia equi and Erlichia phagocytophila. After HGE, patients develop antibodies reactive with E. equi and E. phagocytophila; thus, we hypothesized that these species are closely related and share significant antigenicity. Antisera from humans, horses, dogs, and cattle were tested by indirect fluorescent-antibody assay (IFA) for antibodies reactive with E. equi and other ehrlichiae and tested by immunoblot to identify the specific reactions with E. equi. All convalescent-phase sera from human patients with HGE and from animals infected or immunized with E. equi or E. phagocytophila had antibodies reactive with E. equi by IFA; no reactions with Ehrlichia chaffeensis occurred with these sera, and only one horse naturally infected with E. equi had a serologic reaction against Ehrlichia sennetsu. Human and animal sera obtained after infection or immunization with other Ehrlichia, Rickettsia, and Bartonella species did not react with E. equi by IFA. E. equi immunoblots revealed as many as 19 bands with equine anti-E. equi serum. All HGE agent, E. equi, and E. phagocytophila antisera tested reacted with a 44-kDa antigen of E. equi, while other anti-Ehrlichia spp. sera reacted with this antigen rarely or not at all. HGE agent, E. equi, and E. phagocytophila antisera but not other sera also reacted occasionally with 25-, 42-, and 100-kDa antigens. Most sera reacted with antigens between approximately 56 and 75 kDa, probably heat shock proteins. The HGE agent, E. equi, and E. phagocytophila share significant antigenicity by IFA and immunoblot. Coupled with the nearly identical nucleotide sequences of 16S rRNA genes, these data indicate that E. equi, E. phagocytophila, and the human granulocytic ehrlichia are closely related or identical species.

Animals↗
PubMed1997

Prevalence of granulocytic Ehrlichia infection among white-tailed deer in Wisconsin.

Human granulocytic ehrlichiosis (HGE) is caused by an agent that is nearly indistinguishable from the veterinary pathogens Ehrlichia equi and Ehrlichia phagocytophila. The deer tick, Ixodes scapularis, is a vector of the HGE agent, and the white-tailed deer is the primary host for adult Ixodes ticks. We assessed the distribution of granulocytic Ehrlichia infection among deer living within (Wisconsin) and outside (western and southern Iowa) the geographic range of L. scapularis. Whole-blood samples were tested for HGE 16S ribosomal DNA (rDNA) by PCR, and E. equi antibody was detected by indirect immunofluorescence assay (IFA). Antibody titers of > or = 1:64 were defined as positive, and all positive samples were retested with a second lot of substrate antigen. E. equi antibody was present in 14 (8%) of 187 Wisconsin deer and 0 of 60 Iowa specimens (rate ratio undefined; P = 0.025). An additional 30 serum samples from Wisconsin deer were excluded because IFA results were discrepant between substrate lots. The reciprocal antibody titers ranged from 64 to 512 (geometric mean, 141) for positive samples. PCR results were positive for 27 (15%) of 181 Wisconsin deer. The prevalence of infection in northwestern Wisconsin deer was not significantly different from that in central Wisconsin deer, as determined by IFA and PCR. In two samples that were sequenced, the 16S rDNA was nearly identical to that of the granulocytic Ehrlichia species but distinct from that of Anaplasma marginale. The DNA sequences of the samples differed from the published sequences for E. equi, E. phagocytophila, and the HGE agent by 1 or 2 nucleotides (> or = 99.1% homology) at phylogenetically informative sites. Granulocytic Ehrlichia organisms in deer are widely distributed within the geographic range of L. scapularis in Wisconsin. Deer may serve as useful sentinels for areas where HGE transmission to humans may occur.

Animals↗
PubMed2004

Molecular epidemiological analysis of Mycoplasma bovis isolates from the United Kingdom shows two genetically distinct clusters.

Mycoplasma bovis is an important veterinary pathogen causing pneumonia, arthritis, and mastitis in infected cattle. We investigated the genetic diversity of 53 isolates collected in the United Kingdom between 1996 and 2002 with pulsed-field gel electrophoresis (PFGE), amplified fragment length polymorphism (AFLP), and random amplified polymorphic DNA (RAPD) analysis. In addition, the influence of variable surface protein (Vsp) profiles on the profiles generated with molecular typing techniques was studied. Both AFLP and RAPD separated the isolates into two distinct groups, but PFGE showed less congruence with the other techniques. There was no clear relationship between the geographic origin or year of isolation of the isolates and the profiles produced. No correlation between Vsp profiles and any of the molecular typing techniques was observed. We propose that RAPD and AFLP provide valuable tools for molecular typing of M. bovis.

Animals↗
PubMed2025

Probing orthobunyavirus reassortment using Bunyamwera and Batai viruses as models.

Reassortment is a critical evolutionary mechanism for segmented viruses, enabling the exchange of intact genome segments during co-infection and driving orthobunyavirus evolution; however, the molecular mechanisms underpinning this process remain unclear. With over 100 orthobunyavirus species, many of which are significant human and veterinary pathogens, understanding how reassortment influences transmissibility and virulence is essential for preempting the emergence of novel pathogens. Here, we use Bunyamwera virus (BUNV) and Batai virus (BATV) as models to explore orthobunyavirus reassortment through reverse genetics. We established the first reverse genetics system for BATV, generated reassortants, and employed minigenome assays to assess replication machinery compatibility. Additionally, we developed a novel hybridization chain reaction assay for high-resolution visualization of viral RNA segments. Our findings revealed that all six reassortants between BUNV and BATV are viable, exhibiting notable phenotypic differences in interferon-deficient (IFNAR-/-) mice. This work introduces essential tools and new insights into orthobunyavirus reassortment and pathogenesis, laying the groundwork for understanding this critical evolutionary process.

Animals↗
PubMed2006

Identification of diagnostic proteins in Mycobacterium avium subspecies paratuberculosis by a whole genome analysis approach.

Mycobacterium avium subspecies paratuberculosis (M. paratuberculosis) is an economically significant veterinary pathogen that causes Johne's disease in cattle and sheep. There is a critical need for improved diagnostic tests to detect M. paratuberculosis infection in these animals. As with many other animal diseases, efforts need to be concentrated on the development of simple, rapid, noninvasive tests that can be performed by veterinarians or animal producers without expensive laboratory equipment. With the genome sequence of M. paratuberculosis now complete, we have taken a different strategy to identify novel proteins that are present uniquely in M. paratuberculosis and are antigenic in the context of infected cattle. Through a whole genome comparison of M. paratuberculosis with other sequenced mycobacterial genomes, we identified a collection of more than 90 genes that are present uniquely in M. paratuberculosis. This list has been further trimmed to 39 after amplification using polymerase chain reaction of unique genes using the genomic deoxyribonucleic acid template from several mycobacterial species and isolates. A selection of the remaining genes has been cloned and expressed in Escherichia coli and purified by affinity chromatography. Successfully purified proteins were analyzed using sera from rabbits immunized with M. paratuberculosis. Furthermore, to identify antigens in the context of disease, sera from cattle with Johne's disease as well as healthy control cattle are used in immunoassays. Using this methodology, we identified the first protein antigens specific to M. paratuberculosis.

Animals↗
PubMed2003

Geographic information systems and spatial analysis of adult Ixodes scapularis (Acari: Ixodidae) in the Middle Atlantic region of the U.S.A.

In the Middle Atlantic region of the U.S.A., the vector of Lyme disease, human granulocytic ehrlichiosis, babesiosis, and other human and veterinary pathogens is the black-legged tick, Ixodes scapularis Say. In 1997 and 1998, 663 adult I. scapularis ticks were collected from 320 transects spanning 66,400 km2 in five states of the Middle Atlantic region. Tick abundance patterns were clustered, with relatively high numbers along the coastal plain of the Chesapeake Bay, decreasing to the west and south. There were significant associations between tick abundance and land cover, distance to water, distance to forest edge, elevation, and soil type.

Animals↗
PubMedDate not supplied

A reverse transcriptase-polymerase chain reaction assay for detecting Highlands J virus.

Highlands J (HJ) virus is an arbovirus frequently recovered at high rates in mosquitoes collected in the eastern United States. HJ virus is primarily a veterinary pathogen causing disease in domestic birds including turkeys, chickens, and partridges. It has an enzootic cycle similar to eastern equine encephalitis (EEE) virus and is often used as an indicator species in EEE surveillance programs. Current immunologic techniques to identify HJ virus are often inefficient and can involve cross-reactivity of antibodies. Therefore, we developed a molecular-based assay by a reverse transcriptase (RT)-polymerase chain reaction (PCR) technique. Primers were constructed from conserved sequences of the E1 coding region from 19 strains of HJ virus. PCR amplifications from serial dilutions of HJ virus-infected Vero cell culture supernatants indicated that this assay could detect viral RNA at concentrations of 10 plaque-forming units per reaction. Extracted RNAs from western equine encephalitis, EEE, LaCrosse, and Jamestown Canyon viruses were not detected with this assay. RNA extracted directly from the brain tissue of a dead house sparrow and from a pool of Culiseta mosquitoes yielded a PCR product of the expected size. The RT-PCR technique developed was both sensitive and specific for detecting HJ virus from infected cell culture supernatants, bird brain tissues, and mosquitoes. This new assay will permit rapid and accurate diagnosis of HJ virus, both enhancing surveillance activities for EEE transmission risk and monitoring infections in domestic poultry and wild birds.

Alphavirus↗
PubMed1991

Ehrlichiosis.

Ehrlichiae are tick-borne rickettsial organisms that are well known as veterinary pathogens. However, since 1986, over 100 cases of human infection by Ehrlichia canis or a closely related species have been identified primarily in the southeastern and south central United States. Human ehrlichiosis is characterized by high fever, rigors, headache, myalgia, anorexia, and, sometimes, gastrointestinal complaints. Rash occurs in a minority of cases. Commonly observed laboratory abnormalities include leukopenia, thrombocytopenia, anemia, and elevated hepatic aminotransferase levels. The illness is tick-borne and tetracycline or tetracycline analogs appear to be effective in treating the illness.

Animals↗
PubMed2001

Transmission of opportunistic pathogens in a veterinary teaching hospital.

Acinetobacter baumannii, Enterococcus faecalis, Enterococcus faecium, and Staphylococcus intermedius isolates from infected surgical wounds and other types of infections in a veterinary teaching hospital were typed by pulsed field gel electrophoresis. A first cluster of infections with a multiresistant A. baumannii strain was observed in dogs and cats in 1998-1999. This strain disappeared after cleaning and disinfection of the companion animals intensive care unit. It was followed in 2000 by a second multiresistant strain, which caused another cluster of infections and was also transmitted to a patient in the nearby horse clinic. Transmission of a multiresistant E. faecium strain between two cats with surgical wound infections was also observed during the same period. No multiresistant S. intermedius strain was observed during this time and transmission of this organism between patients did not seem to occur. The present study demonstrates the potential for hospital nosocomial resistance problems in veterinary medicine similar to those encountered in human medicine. The results suggest that the epidemiology of nosocomial infections with A. baumannii and E. faecium may differ from that of S. intermedius infections and that preventive measures may have to be adapted to the problem organism.

Acinetobacter↗
PubMed2006

Relevant oncogenic viruses in veterinary medicine: original pathogens and animal models for human disease.

Oncogenic viruses are important pathogens in farm and companion animals. These original pathogens are classified in various virus families, such as Retroviridae, Papillomaviridae, and Herpesviridae. Besides a role as pathogens for its original host, animal viruses serve as valuable models for viruses affecting humans, such as hepatitis B virus, and issues of immunity, therapy, but also basic pathophysiological mechanisms, can often only be addressed in those animal systems.

Animals↗
PubMedDate not supplied

[Phenotypic and genotypic methods for epidemiological typing of veterinary important bacterial pathogens of the genera Staphylococcus, Salmonella, and Pasteurella].

Molecular typing methods are capable of providing detailed strain characteristics which are commonly far beyond the capacities of phenotypic typing methods. Such molecular-based characteristics have proved to be very helpful in epidemiological studies of bacterial pathogens. The primary criteria that all typing methods should fulfill include (1) the typeability of the strains in question, (2) the reproducibility of the results, and (3) a high discriminatory power. In general, molecular typing methods can be differentiated with regard to their use in methods that can be applied to virtually all bacteria (e.g. plasmid profiling, ribotyping, macrorestriction analysis) and methods which can only be used for typing of certain bacterial genera or species (e.g. IS200 typing of certain Salmonella enterica subsp. enterica serovars, or coa-PCR of coagulase-positive staphylococci). In the present review, various phenotypic and molecular methods for the epidemiological typing of bacteria of the genera Staphylococcus, Salmonella, and Pasteurella are described and their advantages/disadvantages--also with regard to the fulfillment of the above-mentioned primary criteria--are critically assessed.

Animals↗
PubMedDate not supplied

[Methicillin-resistant Staphylococcus aureus (MRSA) in veterinary medicine: a "new emerging pathogen"?].

The problem of nosocomial infections is of increasing importance in veterinary medicine. As an example, this review summarizes current knowledge regarding methicillin-resistant Staphylococcus aureus (MRSA) as a typical example, as these pathogens are the most important agents of nosocomial infections in human medicine worldwide and are being increasingly reported in veterinary medicine. MRSA are classified by their ability to be resistant against oxacillin/methicillin, this feature being confered by mecA, a gene which was acquired by horizontal gene transfer of the staphylococcal gene cassette (SCCmec). It is this genetic information that enables MRSA to be resistant against all penicillins, cehalosporins and carbapenems. In addition, MRSA are often resistant against a variety of other antiinfectives, i.e. aminoglycosides, macrolides, lincosamide, streptomycins, tetracyclin, chloramphenicol, but also against fluorquinolones and rifampicin. Presumably, these highly adapted strains are particularly able to acquire resistance genes located on plasmids or transposons. They are also able to develop point mutations, further leading to resistant phenotypes. If these pathogens are leading to infectious diseases, veterinarians may be confronted with a worst-case scenario, being left without any antiinfective therapeutic. As Staphylococcus aureus is highly tenacid, professional hygiene management is of utmost importance. The increasing number of published sporadic MRSA infections, MRSA-infectious diseases as well as MRSA outbreaks in veterinary medicine justifies their recognition as a "New Emerging Pathogen". So far, horses and dogs are mostly affected by MRSA. Although transmission between humans and animals has been reported occasionally, the sources, routes of transmission or the epidemiological relevance of MRSA infections in animals are far from being understood. Therefore, epidemiological investigations utilizing molecular typing tools are mandatory. Typing tools like multilocus-sequence-typing (MLST), pulsefield-gelelectrophoresis (PFGE), sequence analysis of the gene encoding protein A (spa-typing) as well as SCCmec-typing are all at hand.

Animals↗