52 research outputs found
Dispersal of Adult Black Marlin (Istiompax indica) from a Great Barrier Reef Spawning Aggregation
The black marlin (Istiompax indica) is one of the largest bony fishes in the world with females capable of reaching a mass of over 700 kg. This highly migratory predator occurs in the tropical regions of the Pacific and Indian Oceans, and is the target of regional recreational and commercial fisheries. Through the sampling of ichthyoplankton and ovaries we provide evidence that the relatively high seasonal abundance of black marlin off the Great Barrier Reef is, in fact, a spawning aggregation. Furthermore, through the tracking of individual black marlin via satellite popup tags, we document the dispersal of adult black marlin away from the spawning aggregation, thereby identifying the catchment area for this spawning stock. Although tag shedding is an issue when studying billfish, we tentatively identify the catchment area for this stock of black marlin to extend throughout the Coral Sea, including the waters of Papua New Guinea, the Solomon Islands, Micronesia, New Caledonia, Kiribati, Vanuatu, Fiji, Tuvalu and Nauru
Immigration and Internal Migration 'Flight' from US Metropolitan Areas: Toward a New Demographic Balkanisation
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/68704/2/10.1080_00420989550012861.pd
Characterising the Mucosal and Systemic Immune Responses to Experimental Human Hookworm Infection
The mucosal cytokine response of healthy humans to parasitic helminths has never been reported. We investigated the systemic and mucosal cytokine responses to hookworm infection in experimentally infected, previously hookworm naive individuals from non-endemic areas. We collected both peripheral blood and duodenal biopsies to assess the systemic immune response, as well as the response at the site of adult worm establishment. Our results show that experimental hookworm infection leads to a strong systemic and mucosal Th2 (IL-4, IL-5, IL-9 and IL-13) and regulatory (IL-10 and TGF-Ξ²) response, with some evidence of a Th1 (IFN-Ξ³ and IL-2) response. Despite upregulation after patency of both IL-15 and ALDH1A2, a known Th17-inducing combination in inflammatory diseases, we saw no evidence of a Th17 (IL-17) response. Moreover, we observed strong suppression of mucosal IL-23 and upregulation of IL-22 during established hookworm infection, suggesting a potential mechanism by which Th17 responses are suppressed, and highlighting the potential that hookworms and their secreted proteins offer as therapeutics for human inflammatory diseases
Community Management of Endemic Scabies in Remote Aboriginal Communities of Northern Australia: Low Treatment Uptake and High Ongoing Acquisition
Like many impoverished areas around the world, Aboriginal communities in Australia experience an unacceptably high burden of scabies, skin infections, and secondary complications. Young children are most at risk. Our study investigated scabies in a remote setting with very high rates of skin disease, a high level of household overcrowding, and limited infrastructure for sanitation and preventive health measures. We assessed uptake of scabies treatment and scabies acquisition following provision of treatment by a community-based skin program. In a household where scabies was present, we found that treatment with topical permethrin cream of all close contacts can significantly reduce a susceptible individual's risk of infection. Our findings also demonstrate the challenges of achieving a high level of treatment participation, with limited permethrin use observed among household contacts. This suggests an urgent need for a more practical treatment option. International efforts to reduce childhood morbidity and mortality have demonstrated the efficacy of numerous child health interventions but have also highlighted the deficits in their delivery and implementation. Experiences like this, where the effectiveness of a coordinated local program delivering an efficacious intervention is hampered by poor treatment uptake and ongoing transmission, are an important and timely message for researchers, program managers, and policy-makers
Effect of Hookworm Infection on Wheat Challenge in Celiac Disease β A Randomised Double-Blinded Placebo Controlled Trial
Background and Aims: The association between hygiene and prevalence of autoimmune disease has been attributed in part to enteric helminth infection. A pilot study of experimental infection with the hookworm Necator americanus was undertaken among a group of otherwise healthy people with celiac disease to test the potential of the helminth to suppress the immunopathology induced by gluten
Microarray-Based Analysis of Differential Gene Expression between Infective and Noninfective Larvae of Strongyloides stercoralis
Strongyloides stercoralis is a soil-transmitted helminth that
affects an estimated 30β100 million people worldwide. Chronically infected
persons who are exposed to corticosteroids can develop disseminated disease, which
carries a high mortality (87β100%) if untreated. Despite this, little is
known about the fundamental biology of this parasite, including the features that
enable infection. We developed the first DNA microarray for this parasite and used it
to compare infective third-stage larvae (L3i) with non-infective first stage larvae
(L1). Using this method, we identified 935 differentially expressed genes. Functional
characterization of these genes revealed L3i biased expression of heat shock proteins
and genes with products that have previously been shown to be immunoreactive in
infected humans. Genes putatively involved in transcription were found to have L1
biased expression. Potential chemotherapeutic and vaccine targets such as
far-1, ucr 2.1 and hsp-90 were
identified for further study
Habitat partitioning and vulnerability of sharks in the Great Barrier Reef Marine Park
Sharks present a critical conservation challenge, but little is known about their spatial distribution and vulnerability, particularly in complex seascapes such as Australia's Great Barrier Reef Marine Park (GBRMP). We review (1) the distribution of shark species among the primary habitats of the GBRMP (coral reefs, inshore/shelf, pelagic and deep-water habitats) (2) the relative exploitation of each species by fisheries, and (3) how current catch rates interact with their vulnerability and trophic index. Excluding rays and chimaeras, we identify a total of 82 shark species in the GBRMP. We find that shark research in the GBRMP has yielded little quantitative information on most species. Reef sharks are largely site-fidelic, but can move large distances and some regularly use non-reef habitats. Inshore and shelf sharks use coastal habitats either exclusively or during specific times in their life cycle (e.g. as nurseries). Virtually nothing is known about the distribution and habitat use of the GBRMP's pelagic and deep-water sharks. At least 46 species (53.5 %) are caught in one or more fisheries, but stock assessments are lacking for most. At least 17 of the sharks caught are considered highly vulnerable to exploitation. We argue that users of shark resources should be responsible for demonstrating that a fishery is sustainable before exploitation is allowed to commence or continue. This fundamental change in management principle will safeguard against stock collapses that have characterised many shark fisheries
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