Molecular epidemiology of Mycobacterium bovis: usefulness in international trade

Tuberculosis (TB) represents a barrier for free trade of livestock between Mexico and the United States of America (US). In spite of efforts from Mexico to export TB-free animals, some of those found with TB lesions in slaughterhouses in the US are traced back to that country. Therefore, the purpose of this study was to determine, through molecular epidemiology, the most probable source of infection for cattle found with TB lesions in the US. Ninety M. bovis isolates, 50 from Mexico obtained from cattle in 8 different states, and 40 from the US from cattle, deer, elk and feral pigs from 7 different states were included in the study. All samples were analyzed in both laboratories, Mexico and the US, following the same protocol for molecular analysis by spoligotyping. Twenty-seven clusters, ranging from 1 to 18 genetically similar strains were found. Some clustering by country was observed, strains from cattle and deer in Michigan in the US fell into the same cluster, suggesting transmission between species. These results, combined with epidemiological information suggest that despite of the possibility that some animals with lesions in the US come from Mexico as false negatives, the US has its own source of infection, must probably in dairy cattle and wildlife. Genetic diversity of isolates from Mexico was larger than that in the US, which could be a consequence of the endemic status of the disease and the indiscriminate movement of animals between regions.     

Interface of epidemiology, pet population issues and policy

Progress has been made towards eliminating Rowan's "statistical black hole" regarding pet populations and their dynamics, although deficiencies remain. The challenge in the coming decade will be to continue the progress, and generate meaningful epidemiologic data. Veterinary epidemiologists will continue to play an important role in the generation, dissemination and translation of results from their studies into coherent, effective companion animal welfare policy.     

Pull-through technique for palmar digital neurectomy: forty-one horses (1998-2004)

Objectives— To report outcome of horses treated for navicular syndrome using a pull-through (PT) technique for palmar digital neurectomy (PDN).
Design— Retrospective study.
Animals— Horses (n=41) with navicular syndrome (NS).
Methods— Medical records (1998–2002) for horses that had NS and failed to respond to conservative management that had unilateral or bilateral forelimb, biaxial PDN were reviewed. Outcome for up to 6 years was obtained by telephone questionnaire or lameness examination. Survival analysis was used to assess time to recurrence of lameness.
Results— One year after PDN, 36 horses (88%) were free of lameness. Mean survival with no lameness after surgery was estimated at 4.14±0.33 years (median, 5 years).
Conclusions— PT–PDN technique resulted in soundness for 88% of horses for at least 1 year. PT–PDN was easily and quickly performed without specialized equipment, and had a low incidence of complications.
Clinical Relevance— The PT technique is an effective and viable alternative surgical method for PDN.     

Antibiotic intravenous regional perfusion for successful resolution of distal limb infections: two cases

Intravenous regional perfusion is a common technique for treating infections of the extremities in humans and horses. It has the advantage of achieving very high antibiotic concentrations in affected tissues. This technique was used to clinically resolve deep, mixed infections involving bones and joints in a swamp wallaby and a lesser kudu. Both infections were severe and considered life-threatening, because amputation was not feasible, systemic antibiotic treatment had failed, and both animals were in pain and had evidence of the systemic effects of the infections. In the wallaby, once daily treatments with imipenem for 5 days resulted in a return to normal function within 1 mo. In the kudu, four treatments using both ampicillin/sulbactam followed by enrofloxacin were performed every 2 days, followed by two treatments with ampicillin/sulbactam alone 2 wk later. Resolution of this case was achieved in less than 2 mo. The only adverse effect noted was phlebitis in the kudu, which resolved with conservative therapy. Healing was rapid in both cases and was apparent after two treatments. This report demonstrates the efficacy and flexibility of intravenous regional perfusion for the treatment of severe infections of the digits in nondomestic species.     

Adaptation and evaluation of a rapid test for the diagnosis of sheep scrapie in samples of rectal mucosa.

In recent publications, it was shown that disease-associated prion protein (PrP(d)) accumulates in the lymphoid tissue of the rectal mucosa of a high proportion of scrapie-infected sheep at clinical and preclinical stages, regardless of several host factors; PrP(d) can also be detected in biopsy specimens of rectal mucosa, with an increased probability proportional to age or incubation period and with an efficiency almost identical to that of tonsil biopsies. Rectal biopsies have the advantages of providing higher numbers of lymphoid follicles and of being simpler to perform, which makes them suitable for scrapie screening in the field. In biopsy samples, PrP(d) could be demonstrated by immunohistochemical (IHC) and Western immunoblotting methods, and the purpose of the present study was to optimize and evaluate a "rapid test" for the diagnosis of scrapie in rectal biopsy samples. The HerdChek CWD (chronic wasting disease) antigen EIA (enzyme immunoassay) test was chosen and, once optimized, provided specificity and sensitivity figures of 99.2% and 93.5%, respectively, compared with IHC results in the same samples obtained at a postmortem. The sensitivity of the assay increased from 82.1%, when a single rectal mucosa sample was tested to 99.4% for those sheep in which 3 or more samples were analyzed. Similarly, sensitivity values of the HerdChek CWD antigen EIA test on biopsy samples increased from 95% to 100% for sheep subjected to 1 or 2 sequential biopsies 4 months apart, respectively. Thus, a preclinical diagnosis of scrapie in live sheep can be achieved by a combination of a simple sampling procedure, which can be repeated several times with no detrimental effect for the animals, and a rapid and efficient laboratory method.     

Tumorous crown gall response to iron‐deficiency stress in Fe‐efficient T3238fer and Fe‐inefficeent T3238fer tomatoes

Abstract

Although sunflower (Helianthus annus L.) is an Fe efficient plant, tumorous crown gall tissue development and tissue ability to reduce Fe³⁺ to Fe²⁺ were both diminished by Fe‐deficiency stress. Crown gall also develops readily on Fe‐efficient and Fe‐inefficient tomato cultivars (Lycopersicon esculentum Mill.). The objective of this study was to determine if the effect of a limited Fe supply on the growth, nutrition and reduction of Fe³⁺ to Fe²⁺ by tumorous crown gall would differ between Fe‐efficient T3238FER and Fe‐inefficient T3238fer tomato. Healthy green 25‐day‐old plants were either stem‐inoculated with Agrobacterium tumefaciens to induce tumorous crown gall tissue development or were left uninoculated for comparison. Plants were grown in modified Hoagland nutrient solutions containing 0.0, 0.15, 0.6 and 2.0 mg Fe L^?1. Yield of tumorous crown gall tissue was not diminished by low solution Fe in T3238FER, but was in T3238fer. This was attributed to inability of the T3238fer tomato to make Fe available to itself. Tumor tissue from both cultivars contained more Fe, Cu and P than normal stem tissues, which confirms a modified metabolism in these tissues previously observed in sunflower. An abundant supply of Fe enhances the development and growth of the tumorous crown gall tissue, but a deficient supply of Fe retards its growth.     

Evidence of depleted uranium‐induced hormesis and differential plant response in three grasses

General plant response to depleted uranium (DU) was tested using three widespread range‐grass species, Aristida purpurea Nutt. (purple threeawn), Buchloe dactyloides (Nutt.) Engelm. (buffalograss), and Schizachyrium scoparium (Michx.) Nash (little bluestem). Aboveground, belowground, and total biomass measures of these grasses were analyzed over the five different DU soil concentrations of 0, 50, 500, 5,000, and 25,000 mg kg^‐1. Differential plant response to DU was observed between the three grasses, wiith A. purpurea and B. dactyloides exhibiting a threshold‐type response in which no changes in biomass occurred until the highest treatment level of 25,000 mg kg^‐1 was reached. Schizachyrium scoparium, however, demonstrated a large degree of growth stimulation, or hormesis, at the 50 and 500 mg kg^‐1 DU concentrations. Several possible mechanisms of this hormetic response are offered.     

Identifying the Research Information Needs of the Racing and Breeding Industries in New Zealand: Results of an Online Survey

The aim of this study was to identify the research-based educational needs and preferred dissemination methods for the Thoroughbred and Standardbred racing and breeding industries in New Zealand. An online survey was used to collect data from members of the Thoroughbred and Standardbred industries who were registered with racing and breeding industry governing bodies. A link to the survey was sent to all members with an e-mail address listed in their contact information. The survey was available online for 1 month (May 1-31, 2012). A total of 602 usable survey responses were included in the analysis. Approximately half the population was from the Thoroughbred sector (53%) of the industry, with most respondents being breeders (45%). Respondents were most interested in research-based information on feeding and nutrition, injuries and lameness, health and exercise, and training. Veterinarians, websites, friends or other horse owners, and printed magazines were used most often for obtaining information on equine research; these sources were also rated as most preferred. Social media and other online sources (videos and forums) were rarely used. The survey identified topics of interest to the members of the racing and breeding industries in New Zealand and highlighted preferred sources that could be used to disseminate information. Survey results also highlighted opportunities to better use and adapt current industry sources of information to ensure that the educational needs are being met for this sector of the equine industry in New Zealand.