Norovirus Outbreak Associated with Swimming in a Recreational Lake Not Influenced by External Human Fecal Sources in The Netherlands, August 2012.

Swimming in fecally contaminated recreational water may lead to gastrointestinal illness. A recreational water-associated outbreak of norovirus (NoV) infections affecting at least 100 people in The Netherlands occurred in August 2012. Questionnaire responses from patients indicated swimming in recreational lake Zeumeren as the most likely cause of illness. Most patients visited the lake during the weekend of 18⁻19 August, during which the weather was exceptionally warm (maximum temperatures 32⁻33 °C), and visitor numbers elevated. Patients, mostly children, became ill with gastroenteritis 1⁻6 days (median 2 days) after exposure. Four stool samples from patients were NoV GI positive. Subsurface sandy soil from one of the beaches where most patients swam was NoV GI positive; the water sample was negative. The epidemiological curve and the timeline of investigation based on reported symptoms demonstrate the difficulty in discovering the source in recreational water outbreaks. A NoV outbreak in a recreational lake that is not subjected to external fecal contamination sources shows the need for active communication about human shedding of viruses during and after diarrheal episodes and the advice to refrain from swimming, even a few weeks after the symptoms have resolved.

Regulatory developmental neurotoxicity testing: a model study focussing on conventional neuropathology endpoints and other perspectives.

Our aim was to investigate a model of the morphologic approach proposed in guidelines for developmental neurotoxicity testing (DNT). Hereto, a limited DNT study [EPA Health Effects Test Guidelines OPPTS 870.6300, 1996a. Developmental Neurotoxicity Study "Public Draft", United States Environmental Protection Agency; Prevention, Pesticides and Toxic Substances (7101); EPA 712-C-96-239, June 1996. ] was carried out with different doses of methylazoxy methanol acetate (MAM), known to affect brain morphology and neuron numbers in the developing brain. After gross examination, the brains of F1-animals were further dissected along neuro-anatomical landmarks to ensure homology between tissues of different individuals. The (relative) weight of the brain (parts) was determined. One brain half (alternating left/right to avoid lateralization) was further used for microscopic slide reading and measurement of brain layer width (linear morphometry); the other was set aside for stereologic investigation in a later phase of the study. In the offspring, a clear reduction in brain size (gross macroscopy) and weight (MAM high- and top-dose groups) was observed on postnatal days (PN) 22 and 62, but this reduction was hard to pinpoint in the microscope as the changes primarily appeared quantitative in nature, rather than qualitative. Linear measurements of brain layer width appeared very sensitive and efficient. This first step of a project is presented and the perspectives of a further stereologic investigation are discussed.