Ecological risk assessment of endocrine disruptors.

The European Centre for Ecotoxicology and Toxicology of Chemicals proposes a tiered approach for the ecological risk assessment of endocrine disruptors, integrating exposure and hazard (effects) characterization. Exposure assessment for endocrine disruptors should direct specific tests for wildlife species, placing hazard data into a risk assessment context. Supplementing the suite of mammalian screens now under Organization for Economic Cooperation and Development (OECD) validation, high priority should be given to developing a fish screening assay for detecting endocrine activity in oviparous species. Taking into account both exposure characterization and alerts from endocrine screening, higher tier tests are also a priority for defining adverse effects. We propose that in vivo mammalian and fish assays provide a comprehensive screening battery for diverse hormonal functions (including androgen, estrogen, and thyroid hormone), whereas Amphibia should be considered at higher tiers if there are exposure concerns. Higher tier endocrine-disruptor testing should include fish development and fish reproduction tests, whereas a full life-cycle test could be subsequently used to refine aquatic risk assessments when necessary. For avian risk assessment, the new OECD Japanese quail reproduction test guideline provides a valuable basis for developing a test to detecting endocrine-mediated reproductive effects; this species could be used, where necessary, for an avian life-cycle test. For aquatic and terrestrial invertebrates, data from existing developmental and reproductive tests remain of high value for ecological risk assessment. High priority should be given to research into comparative endocrine physiology of invertebrates to support data extrapolation to this diverse fauna.

Epizootic podoknemidokoptiasis in American robins.

Epizootics of scaly leg disease caused by infection with the submacroscopic mite Knemidokoptes jamaicensis (Acari: Knemidokoptidae) in migratory American robins (Turdus migratorius) from a residential area of Tulsa (Oklahoma, USA) are documented during the winters (December through February) of 1993-94 and 1994-95. Estimates of 60 to > 80% of the birds in several different flights arriving in the area had lesions consistent with knemidokoptic mange. Epizootic occurrence of K. jamaicensis also is confirmed incidentally in American robins from Georgia (USA) in 1995 and 1998 and in Florida (USA) in 1991. These are the first confirmed epizootics of scaly leg attributed to infections with mites specifically identified as K. jamaicensis in North America. Severity of observed lesions in American robins ranged from scaly hyperkeratosis of the feet and legs to extensive proliferative lesions with loss of digits or the entire foot in some birds. Histologically, there was severe diffuse hyperkeratosis of the epidermis which contained numerous mites and multifocal aggregates of degranulating to degenerating eosinophilic heterophils; there was mild to severe superficial dermatitis with aggregates of eosinophilic heterophils and some mononuclear cells. Based on limited data from affected captive birds in Florida, we questioned the efficacy of ivermectin as an effective acaricide for knemidokoptiasis and propose that conditions associated with captivity may exacerbate transmission of this mite among caged birds. While knemidokoptic mange apparently can result in substantial host morbidity and possibly mortality, the ultimate impact of these epizootics on American robin populations presently is unknown.