Enteric campylobacter infection in gnotobiotic calves and lambs   总被引：1，自引：0，他引：1  

H R Terzolo  G H Lawson  K W Angus  D R Snodgrass 《Research in veterinary science》1987,43(1):72-77

Gnotobiotic calves and lambs were infected orally with Campylobacter jejuni, C coli or C hyointestinalis to assess pathogenicity. All animals were successfully colonised and excreted mucoid faeces but showed no other clinical signs. Campylobacters colonised the large intestine better than the small intestine, in which bacterial numbers decreased with time after infection. Campylobacters were found occasionally in the lumen of crypts in close proximity to epithelial cells and included in a mucus-like material. Lesions were mostly in the large intestine in calves whereas in lambs they were present in the ileum. In animals inoculated with C jejuni or C coli scattered crypt abscesses, focal inflammatory infiltrates in the lamina propria and goblet cell discharge were found. In lambs inoculated with C hyointestinalis only minor changes were found in the small intestine. Serum antibody response was either absent or present at a low level only from the 19th day after infection.  相似文献   

Spongy changes in the brains of sheep poisoned by excess dietary copper     

P C Doherty  R M Barlow  K W Angus 《Research in veterinary science》1969,10(3):303-304

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Bacteria-phage antagonistic coevolution in soil     

Gómez P  Buckling A 《Science (New York, N.Y.)》2011,332(6025):106-109

Bacteria and their viruses (phages) undergo rapid coevolution in test tubes, but the relevance to natural environments is unclear. By using a "mark-recapture" approach, we showed rapid coevolution of bacteria and phages in a soil community. Unlike coevolution in vitro, which is characterized by increases in infectivity and resistance through time (arms race dynamics), coevolution in soil resulted in hosts more resistant to their contemporary than past and future parasites (fluctuating selection dynamics). Fluctuating selection dynamics, which can potentially continue indefinitely, can be explained by fitness costs constraining the evolution of high levels of resistance in soil. These results suggest that rapid coevolution between bacteria and phage is likely to play a key role in structuring natural microbial communities.  相似文献   

Intermittent Escherichia coli O157:H7 colonisation at the terminal rectum mucosa of conventionally-reared lambs     

Best A  Clifford D  Crudgington B  Cooley WA  Nunez A  Carter B  Weyer U  Woodward MJ  La Ragione RM 《Veterinary research》2009,40(1):9-Feb;40(1):09

In cattle, the lymphoid rich regions of the rectal-anal mucosa at the terminal rectum are the preferred site for Escherichia coli O157:H7 colonisation. All cattle infected by rectal swab administration demonstrate long-term E. coli O157:H7 colonisation, whereas orally challenged cattle do not demonstrate long-term E. coli O157:H7 colonisation in all animals. Oral, but not rectal challenge of sheep with E. coli O157:H7 has been reported, but an exact site for colonisation in sheep is unknown. To determine if E. coli O157:H7 can effectively colonise the ovine terminal rectum, in vitro organ culture (IVOC) was initiated. Albeit sparsely, large, densely packed E. coli O157:H7 micro-colonies were observed on the mucosa of ovine and control bovine terminal rectum explants. After necropsy of orally inoculated lambs, bacterial enumeration of the proximal and distal gastrointestinal tract did suggest a preference for E. coli O157:H7 colonisation at the ovine terminal rectum, albeit for both lymphoid rich and non-lymphoid sites. As reported for cattle, rectal inoculation studies were then conducted to determine if all lambs would demonstrate persistent colonisation at the terminal rectum. After necropsy of E. coli O157:H7 rectally inoculated lambs, most animals were not colonised at gastrointestinal sites proximal to the rectum, however, large densely packed micro-colonies of E. coli O157:H7 were observed on the ovine terminal rectum mucosa. Nevertheless, at the end point of the study (day 14), only one lamb had E. coli O157:H7 micro-colonies associated with the terminal rectum mucosa. A comparison of E. coli O157:H7 shedding yielded a similar pattern of persistence between rectally and orally inoculated lambs. The inability of E. coli O157:H7 to effectively colonise the terminal rectum mucosa of all rectally inoculated sheep in the long term, suggests that E. coli O157:H7 may colonise this site, but less effectively than reported previously for cattle.  相似文献   

The risk of rinderpest re-introduction in post-eradication era     

Guillaume Fournié  Bryony Anne Jones  Wendy Beauvais  Juan Lubroth  Felix Njeumi  Angus Cameron  Dirk Udo Pfeiffer 《Preventive veterinary medicine》2014

In 2011, ten years after the last reported outbreak, the eradication of rinderpest was declared. However, as rinderpest virus stocks still exist, there remains a risk of rinderpest re-introduction.  相似文献   

FELLOWS OF THE AUSTRALIAN VETERINARY ASSOCIATION     

Angus Packham  Donald Thomas Oxer 《Australian veterinary journal》1969,45(9):428-429

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Development of immunity to incoming radiolabelled larvae in lambs continuously infected with Ostertagia circumcincta   总被引：2，自引：0，他引：2  

D S Seaton  F Jackson  W D Smith  K W Angus 《Research in veterinary science》1989,46(2):241-246

Infective larvae of Ostertagia circumcincta were radiolabelled with 75selenium by a method which did not affect their viability. Three groups of five-month-old lambs were infected daily with 1000 unlabelled infective larvae for four, eight and 12 weeks, respectively. After each period one of these groups and a group of worm-free controls were challenged with three consecutive daily doses of 1000 radiolabelled third stage larvae. The lambs were killed 13 days after the first dose of challenge larvae and their worm burdens examined. The first indication of immunity was retardation of developing worms observed at four weeks. Resistance to the establishment of incoming worms developed between four and eight weeks and a brief period of population turnover probably took place at this time. Simultaneously a greater inhibition of worm development occurred resulting in an increase in the number of parasites recovered as early fourth stage larvae. By 12 weeks the animals were almost completely immune to incoming worms. The development of resistance to incoming worms correlated with a rise in serum antibody titre and an increase in the number of intraepithelial globule leucocytes in the gastric mucosa.  相似文献   

Kinetics of in vitro bovine lymphocyte immunostimulation with a Brucella abortus antigen.     

J M Kaneene  D W Johnson  R K Anderson  R D Angus  D E Pietz  C C Muscoplat 《American journal of veterinary research》1978,39(2):235-239

A Brucella abortus-soluble antigen was investigated, using in vitro assay of lymphocyte immunostimulation, to determine which concentration of this antigen and which period of incubation of the lymphocyte cultures would induce maximum specific lymphocyte immunostimulation as an additional method for further study of B abortus infection in cattle. Soluble antigen was prepared from autoclaved cells of B abortus strain 1119-3. Peripheral blood lymphocytes were obtained from cattle infected with B abortus and from healthy control cattle not infected with B abortus. The lymphocytes were prepared by the Ficoll-Hypaque density gradient technique, suspended in RPMI 1640 medium (1.5 X 10(6)/ml), cultured with several dilutions of soluble antigen, and incubated. Prior to termination of incubation, cultures were labeled with 1 muCi of [3H]thymidine and, after harvesting, assayed for [3H]thymidine incorporation in DNA by a liquid scintillation spectrometer. Maximum specific immunostimulation of lymphocytes from B abortus-infected cattle was induced in this assay system with 6 days' incubation and 22 microgram of protein/ml/1.5 X 10(6) lymphocytes, using protein content to express concentration of soluble antigen in this system.  相似文献   

Otic cytology in health and disease.   总被引：1，自引：0，他引：1  

John C Angus 《Veterinary Clinics of North America: Small Animal Practice》2004,34(2):411-424

Accurate characterization of the primary cause and perpetuating factors is essential for successful management of ear disease in dogs and cats. Cytology is a simple, rapid, and practical diagnostic test that should be performed routinely on any and all patients presented for clinical signs consistent with otitis externa. In combination with clinical signs, otoscopic evaluation, and diagnostic testing of primary disease, serial cytology enhances the ability of veterinarians to diagnose secondary infections, monitor progression of disease, evaluate response to therapy, and make appropriate management decisions. Cytologic specimens should be evaluated for the presence, numbers, and characteristics of three key features: yeast, bacteria, and leukocytes. More than five yeast organisms or more than 25 bacteria per high-powered field is suggestive of significant microbial activity warranting therapeutic intervention. The presence of leukocytes, particularly with phagocytized bacteria, indicates "true infection" rather than overgrowth; if suppurative discharge is present, systemic therapy is needed. Cytology combined with culture and susceptibility is the best method for identification of bacterial overgrowth and infection; however, if only one test can be performed, always choose cytology. Culture results assist in the selection of appropriate antibiotic therapy, but cytology determines whether systemic antibiotics are indicated, which organisms are most significant, and when therapy can be discontinued.  相似文献   

A practical approach to calculate sample size for herd prevalence surveys   总被引：1，自引：0，他引：1  

Humphry RW  Cameron A  Gunn GJ 《Preventive veterinary medicine》2004,65(3-4):173-188

When designing a herd-level prevalence study that will use an imperfect diagnostic test, it is necessary to consider the test sensitivity and specificity. A new approach was developed to take into account the imperfections of the test. We present an adapted formula that, when combined with an existing piece of software, allows improved planning. Bovine paratuberculosis is included as an example infection because it originally stimulated the work. Examples are provided of the trade-off between the benefit (low number of herds) and the disadvantage (large number of animals per herd and exclusion of small herds) that are associated with achieving high herd-level sensitivity and specificity. We demonstrate the bias in the estimate of prevalence and the underestimate of the confidence range that would arise if we did not account for test sensitivity and specificity.  相似文献