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1.
Mycobacterium bovis infection of cats is exceedingly rare in regions where bovine tuberculosis is not endemic. We describe the diagnosis and clinical management of pulmonary M. bovis infection in 2 indoor-housed cats and their association with at least 1 M. bovis–infected human in Texas, USA, in September 2012.  相似文献   
2.
Three serologic methods for antibody detection in elephant tuberculosis (TB), the multiantigen print immunoassay (MAPIA), ElephantTB STAT-PAK kit, and DPP VetTB test, were evaluated using serial serum samples from 14 captive elephants infected with Mycobacterium tuberculosis in 5 countries. In all cases, serological testing was performed prior to the diagnosis of TB by mycobacterial culture of trunk wash or tissue samples collected at necropsy. All elephants produced antibody responses to M. tuberculosis antigens, with 13/14 recognizing ESAT-6 and/or CFP10 proteins. The findings supported the high serodiagnostic test accuracy in detecting infections months to years before M. tuberculosis could be isolated from elephants. The MAPIA and/or DPP VetTB assay demonstrated the potential for monitoring antimycobacterial therapy and predicting TB relapse in treated elephants when continuously used in the posttreatment period. History of exposure to TB and past treatment information should be taken into consideration for proper interpretation of the antibody test results. Data suggest that the more frequent trunk wash culture testing of seropositive elephants may enhance the efficiency of the TB diagnostic algorithm, leading to earlier treatment with improved outcomes.  相似文献   
3.
Bovine brucellosis has been nearly eliminated from livestock in the United States. Bison and elk in the Greater Yellowstone Area remain reservoirs for the disease. During 1990–2002, no known cases occurred in Greater Yellowstone Area livestock. Since then, 17 transmission events from wildlife to livestock have been investigated.  相似文献   
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Campylobacter infection is one of the major causes of ovine abortions worldwide. Historically, Campylobacter fetus subsp. fetus was the major cause of Campylobacter-associated abortion in sheep; however, Campylobacter jejuni is increasingly associated with sheep abortions. We examined the species distribution, genotypes, and antimicrobial susceptibilities of abortion-associated Campylobacter isolates obtained from multiple lambing seasons on different farms in Iowa, Idaho, South Dakota, and California. We found that C. jejuni has replaced C. fetus as the predominant Campylobacter species causing sheep abortion in the United States. Most strikingly, the vast majority (66 of 71) of the C. jejuni isolates associated with sheep abortion belong to a single genetic clone, as determined by pulsed-field gel electrophoresis, multilocus sequence typing, and cmp gene (encoding the major outer membrane protein) sequence typing. The in vitro antimicrobial susceptibilities of these isolates to the antibiotics that are routinely used in food animal production were determined using the agar dilution test. All of the 74 isolates were susceptible to tilmicosin, florfenicol, tulathromycin, and enrofloxacin, and 97% were sensitive to tylosin. However, all were resistant to tetracyclines, the only antibiotics currently approved in the United States for the treatment of Campylobacter abortion in sheep. This finding suggests that feeding tetracycline for the prevention of Campylobacter abortions is ineffective and that other antibiotics should be used for the treatment of sheep abortions in the United States. Together, these results indicate that a single tetracycline-resistant C. jejuni clone has emerged as the major cause of Campylobacter-associated sheep abortion in the United States.  相似文献   
5.
A protocol was optimized for the isolation of Mycobacterium avium subsp. paratuberculosis (MAP) from milk and colostrum, with parameters including chemical decontamination, antibiotics, and different culture media. This study demonstrates that the efficiency of MAP recovery from milk is highly dependent upon the culturing protocol, and such protocols should be optimized to ensure that low concentrations of MAP in milk can be detected.  相似文献   
6.
Mycobacterium avium subsp. paratuberculosis is shed into the milk and feces of cows with advanced Johne''s disease, allowing the transmission of M. avium subsp. paratuberculosis between animals. The objective of this study was to formulate an optimized protocol for the isolation of M. avium subsp. paratuberculosis in milk. The parameters investigated included chemical decontamination with N-acetyl-l-cysteine–sodium hydroxide (NALC-NaOH), alone and in combination with antibiotics (vancomycin, amphotericin B, and nalidixic acid), and the efficacy of solid (Herrold''s egg yolk medium [HEY]) and liquid (Bactec 12B and para-JEM) culture media. For each experiment, raw milk samples from a known noninfected cow were inoculated with 102 to 108 CFU/ml of live M. avium subsp. paratuberculosis organisms. The results indicate that an increased length of exposure to NALC-NaOH from 5 to 30 min and an increased concentration of NaOH from 0.5 to 2.0% did not affect the viability of M. avium subsp. paratuberculosis. Additional treatment of milk samples with the antibiotics following NALC-NaOH treatment decreased the recovery of viable M. avium subsp. paratuberculosis cells more than treatment with NALC-NaOH alone. The Bactec 12B medium was the superior medium of the three evaluated for the isolation of M. avium subsp. paratuberculosis from milk, as it achieved the lowest threshold of detection. The optimal conditions for NALC-NaOH decontamination were determined to be exposure to 1.50% NaOH for 15 min followed by culture in Bactec 12B medium. This study demonstrates that chemical decontamination with NALC-NaOH resulted in a greater recovery of viable M. avium subsp. paratuberculosis cells from milk than from samples treated with hexadecylpyridinium chloride (HPC). Therefore, it is important to optimize milk decontamination protocols to ensure that low concentrations of M. avium subsp. paratuberculosis can be detected.  相似文献   
7.
The objective of this study was to observe early markers of cell-mediated immunity in naïve calves infected with Mycobacterium avium subsp. paratuberculosis and how expression of these markers evolved over the 12-month period of infection. Groups for experimental infection included control (noninfected), oral (infected orally with M. avium subsp. paratuberculosis strain K-10), oral/DXM (pretreatment with dexamethasone before oral inoculation), intraperitoneal (i.p.) inoculation, and oral/M (oral inoculation with mucosal scrapings from a cow with clinical disease) groups. One of the earliest markers to emerge was antigen-specific gamma interferon (IFN-γ). Only i.p. inoculated calves had detectable antigen-specific IFN-γ responses at 7 days, with responses of the other infection groups becoming detectable at 90 and 120 days. All infection groups maintained robust IFN-γ responses for the remainder of the study. At 1 month, calves in the oral and oral/M groups had higher antigen-stimulated interleukin-10 (IL-10) levels than calves in the other treatment groups, but IL-10 secretion declined by 12 months for all calves. T-cell activation markers such as CD25, CD26, CD45RO, and CD5 were significantly upregulated in infected calves compared to noninfected controls. Oral inoculation of calves resulted in significantly increased antigen-specific lymphocyte proliferation at 9 and 12 months, as well as inducible nitric oxide synthase (iNOS) secretion at 6 and 12 months. These results demonstrate that infection of naïve calves with M. avium subsp. paratuberculosis invoked early immunologic responses characterized by robust antigen-specific IFN-γ responses and induction of CD25 and CD45RO expression on T-cell subsets. These were followed by antigen-specific lymphocyte proliferation, iNOS secretion, and expression of CD26 and CD5bright markers in the latter part of the 12-month study.Deciphering host immune responses upon exposure to Mycobacterium avium subsp. paratuberculosis, differentiating the responses due to exposure from true infection, and then further characterizing responses at different stages of infection have been daunting and complex tasks that remain elusive. Early measures of host immune responses to infection with mycobacteria, including M. avium subsp. paratuberculosis, have been dominated by a strong bias toward Th1-mediated gamma interferon (IFN-γ) production. Higher levels of antigen-specific IFN-γ secreted by peripheral blood mononuclear cells (PBMCs) have been reported for animals in the early stages of M. avium subsp. paratuberculosis infection, whether it be natural or experimental infection (11, 18, 22, 24). Since IFN-γ is a key effector cytokine involved in the activation of T cells and macrophages, maturation of dendritic cells, upregulation of major histocompatibility complex (MHC) class I and II molecules, and production of reactive oxygen and nitrogen species by macrophages, it is purported to be not only an immune response variable but also a correlate of immune protection (7, 16). However, it is unlikely that the paradigm of host immune responses in the early stages of infection and subsequent resistance to infection is quite so simplistic. Rather, a complex coordination of immune responses is more probable, with these responses shifting as the host transitions through the different stages of infection and disease (subclinical to clinical).Animal infection models are useful because they can provide a more insightful examination of responses of the naïve host to a singular pathogen. Two recent reviews summarized the efficacy of animal models for paratuberculosis in a wide range of species, including cattle, sheep, goats, deer and other wildlife, and rodents such as mice, rats, and rabbits (2, 8). The majority of experimental models for ruminants have utilized oral inoculation of live Mycobacterium avium subsp. paratuberculosis in order to establish infection, thereby mimicking the fecal-oral route of transmission generally observed in the field. Many of these studies utilized laboratory-adapted strains of M. avium subsp. paratuberculosis in the inocula, while a few studies demonstrated more effective results with clinical isolates of M. avium subsp. paratuberculosis (21, 23). Establishing a reproducible and effective challenge model for cattle, with well-defined host immune responses, is key to the interpretation of future work evaluating vaccines or therapeutics.In the present study, we compared the effectiveness of oral suspensions of a clinical isolate of M. avium subsp. paratuberculosis and a low-passage laboratory strain. We further sought to evaluate the potential of dexamethasone (DXM) administration as an immunosuppressant to enhance infectivity in calves. Lastly, we adapted an intraperitoneal (i.p.) challenge model to neonatal calves and compared it to traditional oral inoculation methods. Although oral inoculation is the most favored mode of infection for M. avium subsp. paratuberculosis challenge models in ruminants, intraperitoneal inoculation has been used successfully in murine models (10). In addition, recent studies that involved surgical intervention to introduce M. avium subsp. paratuberculosis directly into the ileum resulted in colonization of tissues both locally and systemically (1, 25). We desired to mimic this effect without surgery by inoculating M. avium subsp. paratuberculosis directly into the peritoneal cavity. In the present study, measurements of the host cell-mediated immune responses to M. avium subsp. paratuberculosis infection were performed to ascertain the nature and vigor of responses shortly after exposure and over a protracted infection period. The upregulation of these early response variables was correlated with the degree of infectivity in the calves, as determined by the number of positive tissue sites.  相似文献   
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Brucella suis infection was diagnosed in a man from Tonga, Polynesia, who had butchered swine in Oregon, USA. Although the US commercial swine herd is designated brucellosis-free, exposure history suggested infection from commercial pigs. We used whole-genome sequencing to determine that the man was infected in Tonga, averting a field investigation.  相似文献   
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