Wood Susanna A, Selwood Andrew I, Rueckert Andreas, Holland Patrick T, Milne Juliet R, Smith Kirsty F, Smits Bronwyn, Watts Laura F, Cary Craig S
Cawthron Institute, Private Bag 2, Nelson 7001, New Zealand.
Toxicon. 2007 Aug;50(2):292-301. doi: 10.1016/j.toxicon.2007.03.025. Epub 2007 Apr 13.
In November 2005, at least five dogs died rapidly after contact with water from the Hutt River (lower North Island, New Zealand). Necropsy performed 24h later on one of the dogs (a 20-month-old Labrador) revealed few findings of interest, except for copious amounts of froth in the respiratory tract down to the bifurcation of the trachea and large quantities of algal material in the dog's stomach. Low and relatively stable flows in the Hutt River during spring had resulted in the proliferation of benthic cyanobacteria that formed large black/brown mats along the river edge. Samples from the Labrador's stomach contents and cyanobacterial mats were analysed microscopically and screened using chemical and biochemical assays for cyanotoxins: anatoxin-a, homoanatoxin-a, cylindrospermopsins, saxitoxins and microcystins. Liquid chromatography-mass spectrometry (LC-MS) confirmed the presence of the neurotoxic cyanotoxins anatoxin-a and homoanatoxin-a and their degradation products, dihydro-anatoxin-a and dihydro-homoanatoxin-a. This is the first report of homoanatoxin-a and associated degradation product in New Zealand. Based on morphology, the causative species was identified as Phormidium sp. Subsequent phylogenetic analysis of 16S rRNA gene sequences demonstrated that the causative organism was most similar to Phormidium autumnale. Further investigations led to the detection of homoanatoxin-a and anatoxin-a in cyanobacterial mats from four other rivers in the Wellington region (lower North Island, New Zealand). Access restrictions were placed on over 60% of river catchments in the western Wellington region, severely affecting recreational users.
2005年11月，至少有5只狗在接触了来自新西兰北岛下部哈特河的水后迅速死亡。24小时后对其中一只狗（一只20个月大的拉布拉多犬）进行的尸检显示，除了气管分叉以下的呼吸道中有大量泡沫以及狗的胃中有大量藻类物质外，没有什么值得关注的发现。春季哈特河水流较低且相对稳定，导致底栖蓝藻大量繁殖，在河边形成了大片黑色/棕色的藻席。对拉布拉多犬胃内容物和蓝藻藻席样本进行了显微镜分析，并使用化学和生化检测方法对蓝藻毒素进行筛查：包括类毒素-a、高类毒素-a、柱孢藻毒素、石房蛤毒素和微囊藻毒素。液相色谱-质谱联用仪（LC-MS）证实了神经毒性蓝藻毒素类毒素-a和高类毒素-a及其降解产物二氢类毒素-a和二氢高类毒素-a的存在。这是新西兰首次报告高类毒素-a及其相关降解产物。根据形态学，致病物种被鉴定为席藻属。随后对16S rRNA基因序列进行的系统发育分析表明，致病生物与秋季席藻最为相似。进一步调查发现，在新西兰北岛下部惠灵顿地区的其他四条河流的蓝藻藻席中也检测到了高类毒素-a和类毒素-a。惠灵顿地区西部超过60%的河流集水区实施了进入限制，严重影响了休闲使用者。
