A group of 1,623 ovine fecal samples recovered from 65 geographically distinct mutton sheep and prime lamb properties across New South Wales, Australia, were screened for the presence of Shiga toxin-producing Escherichia coli (STEC) virulence factors (stx 1 , stx 2 , eaeA, and ehxA). A subset was cultured for STEC isolates containing associated virulence factors (eaeA and/or ehxA), which were isolated from 17 of 20 (85%) and 19 of 20 (95%) tested prime lamb and mutton sheep properties, respectively. STEC isolates containing stx 1 , stx 2 , and ehxA were most commonly isolated (19 of 40 flocks; 47.5%), and this profile was observed for 10 different serotypes. Among 90 STEC isolates studied, the most common serotypes were O91:H Although isolates belonging to serogroup O157 are regarded as the most clinically significant Shiga toxin-producing Escherichia coli (STEC) strains, the number of non-O157 serotypes recovered from episodes of hemorrhagic colitis and hemolyticuremic syndrome (HUS) continues to increase. Currently over 160 serotypes of E. coli have been isolated from human sources (5,6,13,14,25). Ruminants, in particular (6,7,16,24), but also other domestic animals, including pigs, poultry, cats, and dogs (1,6,8), are natural reservoirs of STEC. Although more than 200 different STEC serotypes have been isolated from cattle (reference 13 and references therein), few studies have extensively examined the presence of STEC in sheep. Existing studies have been performed on comparatively small numbers of sheep or have focused intensively on a single flock or only examined the presence of O157 serotypes (3,12,16,17). Kudva et al. (17) investigated the presence of E. coli O157:H7 in a single flock over a 16-month period and described the presence of non-O157 STEC isolates of serotypes O128:NM, O5:NM, O6:H49, O88:NM, and O91:NM, with various combinations of the virulence-associated genes stx 1 , stx 2 , and eaeA. In Australia, one of the largest sheep-producing countries in the world, recent studies focusing primarily on the southeastern parts of Queensland have suggested that the prevalence of stx in fecal cultures ranges from 69 to 88% (12,22).In this study, we investigated the presence of STEC in fecal enrichment broths derived from 65 geographically diverse flocks of slaughter-age sheep (mutton sheep and prime lambs) in New South Wales, Australia, using a multiplex PCR which detects stx 1 , stx 2 , eaeA, and ehxA (11) and vancomycin-cefixime-cefsulodin blood agar (BVCCA) (18). Mutton sheep and prime lambs represent two different genetic lines of meatproducing animal and comprise sheep of different slaughter ages and production systems, parameters which have been reported to influence STEC colonization in ruminant species (26). Our aim was to isolate STEC strains that contained at least one other virulence factor (eaeA and/or ehxA). These STEC isolates were serotyped and examined for the ability to express Shiga toxins using Vero cell cultures. Commercial properties from 29 prime lamb and 36 mutton sheep flocks we...
The identification of geographic areas where the densities of animals are highest across their annual cycles is a crucial step in conservation planning. In marine environments, however, it can be particularly difficult to map the distribution of species, and the methods used are usually biased towards adults, neglecting the distribution of other life‐history stages even though they can represent a substantial proportion of the total population. Here we develop a methodological framework for estimating population‐level density distributions of seabirds, integrating tracking data across the main life‐history stages (adult breeders and non‐breeders, juveniles and immatures). We incorporate demographic information (adult and juvenile/immature survival, breeding frequency and success, age at first breeding) and phenological data (average timing of breeding and migration) to weight distribution maps according to the proportion of the population represented by each life‐history stage. We demonstrate the utility of this framework by applying it to 22 species of albatrosses and petrels that are of conservation concern due to interactions with fisheries. Because juveniles, immatures and non‐breeding adults account for 47%–81% of all individuals of the populations analysed, ignoring the distributions of birds in these stages leads to biased estimates of overlap with threats, and may misdirect management and conservation efforts. Population‐level distribution maps using only adult distributions underestimated exposure to longline fishing effort by 18%–42%, compared with overlap scores based on data from all life‐history stages. Synthesis and applications. Our framework synthesizes and improves on previous approaches to estimate seabird densities at sea, is applicable for data‐poor situations, and provides a standard and repeatable method that can be easily updated as new tracking and demographic data become available. We provide scripts in the R language and a Shiny app to facilitate future applications of our approach. We recommend that where sufficient tracking data are available, this framework be used to assess overlap of seabirds with at‐sea threats such as overharvesting, fisheries bycatch, shipping, offshore industry and pollutants. Based on such an analysis, conservation interventions could be directed towards areas where they have the greatest impact on populations.
The virulence properties and serotypes of complex Shiga toxin-producing Escherichia coli (cSTEC) were determined in two studies of healthy cattle in eastern Australia. In the first, a snapshot study, 84 cSTEC isolates were recovered from 37 of 1,692 (2.2%) fecal samples collected from slaughter-age cattle from 72 commercial properties. The second, a longitudinal study of three feedlots and five pasture beef properties, resulted in the recovery of 118 cSTEC isolates from 104 animals. Of the 70 serotypes identified, 38 had not previously been reported.
Three species of biennial breeding southern hemisphere albatrosses -Diomedea sanfordi from the Chatham Islands, D. antipodensis from Antipodes Island and D. exulans from South Georgia -were tracked using CLS-Argos satellite system during the 1990s. Harness attachment and duty cycling of transmitters enabled long-term deployments covering both the breeding and nonbreeding ranges. The feeding ranges for breeding birds of each species were different. D. sanfordi foraged over continental shelves to the shelf edge, whereas D. antipodensis and D. exulans ranged widely over deep water to the shelf edge. Mapping of satellite-determined locations for D. sanfordi and D. antipodensis showed that the demarcation was between the 1000 and 2000 m undersea contour. Non-breeding D. sanfordi wintered over the Patagonian shelf or over the Chilean shelf. There they were virtually confined to seas over the continental shelves of <200 m depth, occasionally out to <1000 m depth. Breeding D. exulans from South Georgia feeding chicks over the same period foraged pelagically and along steep continental slopes up to depths >1000 m, and on less steep slopes to 200 m depth. These data provide the best evidence yet of habitat preference and segregation consistent across breeding and non-breeding seasons for closely related seabirds.
An outbreak of Murray Valley encephalitis (MVE) occurred in New South Wales during the first five months of 1974. Specimens from 52 horses with nervous disease collected January to May 1974 were examined histopathological or virologically. Although MVE virus was not isolated, 13 horses had serological evidence of recent infection with MVE virus. Another 4 horses had evidence of recent infection with Ross River virus. Two animals had histological evidence of viral infection of the central nervous system. Attempts to experimentally infect 2 horses with a low dose of MVE virus were not successful by intravenous, intramuscular and subcutaneous routes.
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