Primary irritant and delayed-contact hypersensitivity reactions to the freshwater cyanobacterium Cylindrospermopsis raciborskii and its associated toxin cylindrospermopsin

BACKGROUND: Freshwater cyanobacteria are common inhabitants of recreational waterbodies throughout the world; some cyanobacteria can dominate the phytoplankton and form blooms, many of which are toxic. Numerous reports in the literature describe pruritic skin rashes after recreational or occupational exposure to cyanobacteria, but there has been little research conducted on the cutaneous effects of cyanobacteria. Using the mouse ear swelling test (MEST), we sought to determine whether three toxin-producing cyanobacteria isolates and the purified cyanotoxin cylindrospermopsin produced delayed-contact hypersensitivity reactions. METHODS: Between 8 and 10 female Balb/c mice in each experiment had test material applied to depilated abdominal skin during the induction phase and 10 or 11 control mice had vehicle only applied to abdominal skin. For challenge (day 10) and rechallenge (day 17), test material was applied to a randomly-allocated test ear; vehicle was applied to the other ear as a control. Ear thickness in anaesthetised mice was measured with a micrometer gauge at 24 and 48 hours after challenge and rechallenge. Ear swelling greater than 20% in one or more test mice is considered a positive response. Histopathology examination of ear tissues was conducted by independent examiners. RESULTS: Purified cylindrospermopsin (2 of 9 test mice vs. 0 of 5 control mice; p = 0.51) and the cylindrospermopsin-producing cyanobacterium C. raciborskii (8 of 10 test mice vs. 0 of 10 control mice; p = 0.001) were both shown to produce hypersensitivity reactions. Irritant reactions were seen on abdominal skin at induction. Two other toxic cyanobacteria (Microcystis aeruginosa and Anabaena circinalis) did not generate any responses using this model. Histopathology examinations to determine positive and negative reactions in ear tissues showed excellent agreement beyond chance between both examiners (κ = 0.83). CONCLUSION: The irritant properties and cutaneous sensitising potential of cylindrospermopsin indicate that these toxicological endpoints should be considered by public health advisors and reservoir managers when setting guidelines for recreational exposure to cyanobacteria

Contribution to the Methodology for the Development of Acute Exposure Threshold Levels in Case of Accidental Chemical Release

The ACUTEX project was a three-year research activity funded within the EU 5th Framework Programme for Research and Technology Development. Its objective was to develop the methodology, the software tools and a Technical Guidance Document (TGD) for establishing European Acute Exposure Threshold Levels (AETLs) in case of accidental chemical release. The methodology to derive AETLs is intended to speed-up the harmonised implementation of the Council Directive 96/82/EC known as the SEVESO II Directive on the control of major-accident hazards involving dangerous substances. In developing the methodology, the different national practices in industrial accident risk assessment, for both emergency and land-use planning, have been taken into account. The intention is that the new methodology would become a recommended and harmonised tool used by experts on the safety of production installations and be endorsed by risk decision-makers in the whole EU. [...