http://academic.oup.com/milmed/article-pdf/146/1/60/24125826/milmed-146-1-60.pdf

Biochemical Tests for Identification of Medical Bacteria

Parasites of North American Freshwater Fishes

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/pdf/the-consequences-of-feminization-in-breeding-groups-of-wild-1n65pr4ozz.pdf

The Consequences of Feminization in Breeding Groups of Wild Fish

Intersex and reproductive impairment of wild fish exposed to multiple municipal wastewater discharges

any of the myriad problems in the u.s. mortgage market could have been contained, but together they caused a crisis that spread across the globe T HE causes of the crisis in subprime mortgages have become clear. They started with poor underwriting practices, which became legion. But damage was propagated at each stage of the complicated process in which a risky home loan was originated, then became an asset-backed security that then formed part of a collateralized debt obligation (CDO) that was rated and sold to investors. What is not so clear, though, is how these losses could spread to other parts of the global financial system. Like an epidemic in which an invisible virus infects many people and communities, the financial crisis spread when losses to intermediaries in one nontransparent market raised concerns about liquidity and solvency elsewhere. Just as diseases are passed on by close human contact, pests, and contaminated food, so this financial crisis has been transmitted through connected markets and institutions while leaving others largely untouched. We examine the origins of the subprime crisis and the various places, some of them surprising, where the effects of the crisis have been found—such as markets in which banks make loans to one another, short-term commercial paper, and even municipal bonds.

An outbreak; of what?

Intersex, or the presence of characteristics of both sexes, in fishes that are normally gonochoristic has been used as an indicator of exposure to estrogenic compounds. In 2003, during health assessments conducted in response to kills and a high prevalence of skin lesions observed in smallmouth bass Micropterus dolomieu in the South Branch of the Potomac River, the presence of immature oocytes within testes was noted. To evaluate this condition, a severity index (0-4) was developed based on the distribution of oocytes within the testes. Using gonad samples collected from 2003 to 2005, the number of histologic sections needed to accurately detect the condition in mature smallmouth bass was statistically evaluated. The reliability of detection depended on the severity index and the number of sections examined. Examining five transverse sections taken along the length of the gonad resulted in a greater than 90% probability of detecting testicular oocytes when the severity index exceeded 0.5. Using the severity index we compared smallmouth bass collected at selected sites within the South Branch during three seasons in 2004. Seasonal differences in severity and prevalence were observed. The highest prevalence and severity were consistently noted during the prespawn-spawning season, when compared with the postspawn season. In 2005, smallmouth bass were collected at selected out-of-basin sites in West Virginia where fish kills and external skin lesions have not been reported, as well as at sites in the Shenandoah River, Virginia (part of the Potomac drainage), where kills and lesions occurred in 2004-2005. The prevalence of testicular oocytes is discussed in terms of human population and agricultural intensity.

/pdf/intersex-testicular-oocytes-in-smallmouth-bass-from-the-1gtpxtexjn.pdf

Intersex (Testicular Oocytes) in Smallmouth Bass from the Potomac River and Selected Nearby Drainages

Skin lesions and spring mortality events of smallmouth bass Micropterus dolomieu and selected other species were first noted in the South Branch of the Potomac River in 2002. Since that year morbidity and mortality have also been observed in the Shenandoah and Monocacy rivers. Despite much research, no single pathogen, parasite, or chemical cause for the lesions and mortality has been identified. Numerous parasites, most commonly trematode metacercariae and myxozoans; the bacterial pathogens Aeromonas hydrophila, Aeromonas salmonicida, and Flavobacterium columnare; and largemouth bass virus have all been observed. None have been consistently isolated or observed at all sites, however, nor has any consistent microscopic pathology of the lesions been observed. A variety of histological changes associated with exposure to environmental contaminants or stressors, including intersex (testicular oocytes), high numbers of macrophage aggregates, oxidative damage, gill lesions, and epidermal papillomas, were observed. The findings indicate that selected sensitive species may be stressed by multiple factors and constantly close to the threshold between a sustainable (healthy) and nonsustainable (unhealthy) condition. Fish health is often used as an indicator of aquatic ecosystem health, and these findings raise concerns about environmental degradation within the Potomac River drainage. Unfortunately, while much information has been gained from the studies conducted to date, due to the multiple state jurisdictions involved, competing interests, and other issues, there has been no coordinated approach to identifying and mitigating the stressors. This synthesis emphasizes the need for multiyear, interdisciplinary, integrative research to identify the underlying stressors and possible management actions to enhance ecosystem health.

J. D. Hedrick

Papers

Intersex (Testicular Oocytes) in Smallmouth Bass from the Potomac River and Selected Nearby Drainages

Mortality of Centrarchid Fishes in the Potomac Drainage: Survey Results and Overview of Potential Contributing Factors