Features of Ciguatera Fish Poisoning Cases in Hong Kong 2004-2007

Ohjective To review the clinical features and laboratory investigations of ciguatera patients in Hong Kong between 2004 and 2007 in order to show the timely sampling of implicated fish from ciguatera victims and application of validated mouse bioassay for confirming suspected clinical cases of ciguatera. Methods Diagnosis of the ciguatera victims was based on history of coral fish consumption and clinical presentations stated in official guidelines for clinical diagnosis of ciguatera fish poisoning in Hong Kong. Food remnants of coral fish samples were collected swiftly from ciguatera victims between 2004 and 2007 for ciguatoxins （CTXs） analysis. Results Major clinical symptoms in ciguatera patients included gastrointestinal and neurological effects including limb numbness and diarrhoea, which developed at 0.5 to 15 hours after consumption of fish. In most cases, neurological symptoms were more common than gastrointestinal symptoms. A broad range of attack rate （10%-100%） was observed in each ciguatera outbreak. Validated mouse bioassay on ether extracts of the food remnant samples confirmed that all were CTXs-positive （〈0.5 - 4.3 MU/20 mg ether extract） and directly linked to the corresponding ciguatera cases. Conclusion Consistency between clinical and laboratory analysis for ciguatera poisoning illustrates the application of laboratory mouse bioassay in a timely fashion for confirming ciguatera poisoning cases and implementing effective public health measures. With further improvement in laboratory techniques, features of ciguatera fish poisoning cases can be better defined, Further studies are needed to determine the risk of each class of CTXs （Pacific-, Indian- and Caribbean-CTXs） in Hong Kong.

Quantitative Evaluation of Commercially Available Test Kit for Ciguatera in Fish

Reliability of the commercially available Cigua-Check? test kits to identify ciguateric fish was evaluated by assessing the uniformity of conclusions by multiple readers examining identical sticks. One hundred and eighty-eight samples of two types of reef fish were tested for ciguatera using Cigua-Check? test strips. Paired subsamples of all specimens were also analyzed via the more rigorous N2a neuroblastoma mouse bioassay that is specific for aberration of Na+-channel activity that is presumptive for ciguatera fish poisoning. In a double blind trial, four individuals visually examined identical Cigua-Check? strips to conclude whether the samples were positive or negative for ciguatera. Of the 121 samples that were shown to be positively ciguatoxic via bioassay, the four strip readers were in agreement in concluding positive ciguateric status in 9.9% of the samples;these four readers concluded these positive samples were negative for ciguatera in 26.2% of these bioassay-positive samples. Of the 67 samples that were shown in N2a bioassay to be negatively ciguatoxic, the four readers were in agreement in concluding a negative ciguateric status in 26.9% of the samples;these four strip readers concluded these same samples were positive for ciguatera in 14.9% of these negative samples. The low levels of uniform conclusions among readers examining identical test strips, and the low frequency of agreement with the correct ciguateric status as shown by separate N2a neuroblastoma analyses indicate severe short-comings in the reliability of these test kits to accurately reflect the ciguateric status of samples. The level of uncertainty associated with Cigua-Check? test kits indicate a continuing need for improvement of a simple, rapid, and reliable means to identify ciguateric fish.

Marine Fish Toxins in Thailand: Report of 6 Suspected Ciguatera Cases

Food poisoning or gastroenteritis is a common diagnosis for individuals who have nausea, vomiting and diarrhea after ingestion of fish. When also manifesting neurological symptoms, these are blamed on puffer fish poisoning, but ciguatera fish poisoning (CFP) can also manifest only with gastroenteritis, without neurological complications and remain undiagnosed. We report patients who fulfilled criteria of CFP suffering from severe GI disturbances, neurological manifestations, compromised cardiovascular status and autonomic dysfunction. All recovered within 1 - 3 days with supportive treatment. There were two small outbreaks: one in Bangkok in 2007 (2 patients) and another (2009) in Phuket (4 patients). All patients consumed the same unidentified fish portion and had severe GI symptoms. One had acute ventilatory failure requiring intubation whereas the remaining had neurological disturbances consisting of paresthesia, severe vertigo and ataxia. Absence of reflex tachycardia was noted in all patients who had severe volume depletion and shock. The most severe patient could be extubated within 24 hours and was discharged in 48 hours. All of the remaining recovered completely within 48 hours. Severe abdominal pain, nausea and vomiting and autonomic dysfunction in the form of bradycardia in the presence of hypotension were seen. Dramatic recovery within 48 hours occurred in all cases. None of the fish considered to have been responsible was available for testing. Physicians should be aware of CFP intoxication in the differential diagnosis of gastroenteritis-like syndromes after eating seafood.

Comment on“Quantitative Evaluation of Commercially Available Test Kit for Ciguatera in Fish”

This letter is in regards to the paper, “Quantitative evaluation of commercially available test kit for ciguatera in fish” [1]. We were compelled to respond because the entire premise of this paper is flawed, thus invalidating its stated conclusions. The data presented in the paper is derived from the opinions of four independent readers who evaluated identical Cigua-Check? test sticks to screen fish samples for ciguatoxin (CTX), the results of which were then compared with corresponding samples tested in a non-specific bioassay with questionable statistics (see Table 1 [1]). In addition to several factual errors presented in the paper, we have identified several issues with this study, such as insufficient detail and questionable data analyses, that make its interpretations unreliable.

中国南部沿海近岸西加鱼毒素研究

为了查清我国南部沿海珊瑚礁鱼类体内的西加鱼毒素状况,首次在海南三亚、琼海、广西涠洲岛、珠海担杆列岛、广东徐闻县灯楼角和福建东山岛收集渔民从附近珊瑚礁海域捕捞的野生鱼类,采用酶联免疫法、小白鼠生物法和高效液相色谱质谱联用法进行毒素测定.结果表明,6个调查海区均检测出染毒鱼类,总阳性检出率达50%,其中福建东山岛（77.8%）〉广东徐闻县灯楼角（66.7%）〉广东珠海担杆列岛（55.6%）〉广西涠洲岛（37.5%）〉海南三亚（37.5%）〉海南琼海（16.7%）,与海域环境质量可能存在一定的关联.鱼组织毒素含量为0~169ngP-CTX-1/kg肉,8个样品（占总样17.4%）超过100ng P-CTX-1/kg肉,达到可致人中毒水平.染毒鱼种类繁多,主要包括蝴蝶鱼科（Chaetodontidae）、鹦嘴鱼科（Scaridae）、鳂科（Holocentridae）、笛鲷科（Lutjanidae）和鮨科（Serranidae）.酶联免疫法与小鼠生物法对鱼毒定性检测结果基本一致,但仅在福建东山岛2个鱼样中检测到P-CTX-1成分.染毒鱼类的毒素含量和鱼体重/体长没有相关性,也与其食性无关.

赤潮毒素研究进展

近年来,赤潮是全球最严重的海洋生态灾害之一,在我国也尤为突出。本文就赤潮毒素麻痹性贝毒、腹泻性贝毒、记忆缺失性贝毒、神经性贝毒,以及西加鱼毒的分布特征、产毒藻类、化学组分与结构、毒素转化、致毒机理、食用标准、检测方法等国内外研究进展,进行系统的论述,为我国的赤潮监测和灾害防治提供参考。

中国珊瑚礁毒鱼类的研究

本文较全面地叙述珊瑚礁毒鱼中毒的定义 ,珊瑚礁鱼毒素的毒源、毒理作用 ,中毒症状、治疗及预防 ,毒鱼种类。经 2 0多年来的调查研究 ,在中国的台湾、西沙群岛、海南岛南部共发现 45种珊瑚礁鱼类为有毒种。

雪卡毒素产毒藻(岗比亚藻)研究进展

雪卡毒素是一类富集于海洋珊瑚礁鱼体内的聚醚类化合物,由底栖小型甲藻岗比亚藻产生,经海洋食物链传递代谢为雪卡毒素并使鱼类染毒。雪卡毒素毒性强,是已知的危害性较严重的海洋生物毒素之一。然而,长期以来该毒素产毒藻(岗比亚藻)在分类学领域存在诸多争议。本文由此对国际上现有研究结果进行系统整理与归纳,内容包括岗比亚藻的分类与分布、生理生态学、毒理学,并提出研究展望。本文重点阐述了岗比亚藻的地理区域扩张事实、与大型附着基质藻的关系、环境因子对其生长和产毒的影响、种内和种间的产毒特征差异等。在此基础上,结合我国在该领域的研究现状,提出建议和展望。

小鼠生物检测法测定热带性珊瑚礁鱼毒性的研究

目的：研究小鼠生物检测法测定热带性珊瑚礁鱼毒性的检测方法，以预防雪卡毒素引起的食物中毒。方法：鱼肉组织在70℃蒸煮后经丙酮、乙醚、甲醇、正已烷等有机溶剂提取净化得到脂溶性毒素粗提液，对18～22g雄性小白鼠进行腹腔注射，观察24h，采用公式log（MU）=2．3log（1＋1／T）计算毒性大小。结果：有毒检体使小鼠产生行动迟缓、腹泻、呼吸困难、甚至死亡等症状。在采集的7份样品中，检出1份中毒样品毒性为0．11MU／g。其余均未检出毒性。结论：小鼠生物检测法是目前检测珊瑚礁鱼中雪卡毒素的一种有效、简便、经济、实用的方法，适用于珊瑚礁鱼毒性大小的研究和可疑样品的快速初筛。

苏眉鱼中毒的急救护理

目的提高对苏眉鱼类中毒的认识,避免和防范大规模中毒事件的发生。方法分析34例苏眉鱼中毒患者的临床资料,总结临床急诊抢救护理经验,并追踪调查半年内患者的情况。结果苏眉鱼中毒多在2～10小时发病,以急性胃肠炎表现为主,多伴有较长时间温度感觉倒错,部分患者遗留有不同程度的神经系统症状及性欲减退。34例中毒患者18例治愈,16例好转。结论苏眉鱼中毒是一种严重的中毒,医务人员和卫生行政部门应高度重视。

一种基于RFLP分析的冈比亚藻检测方法的建立

雪卡毒素作为一种脂溶性藻毒素近年来日益引起人们的重视,冈比亚藻(Gambierdiscus spp.)是雪卡毒素的主要产生藻.不同的冈比亚藻具有不同的生长特性和产毒性能,且存在地域差异性,因而对冈比亚藻的监测存在较大挑战.建立一种快速简单地鉴定冈比亚藻及其种群结构的方法,是基础科研和社会公众关心的共性问题.为此,以加勒比海的10种冈比亚藻为受试生物,应用限制性片段长度多态性(restriction fragment length polymorphism,RFLP)分析技术,通过生物软件分析发现受试藻的限制性内切酶Aci I具有良好的特异性和灵敏性,可有效区分目前已鉴定的10种冈比亚藻.验证实验中,通过与分离自野外环境的多株冈比亚藻进行酶切电泳和DNA测序,证实了Aci I的有效性和可靠性.结果表明,该Aci I分子具有检测自然环境中冈比亚藻属性和追踪其种群结构变化的潜力,对雪卡毒素的预判与风险评估具有重要的借鉴意义.

2004～2006年深圳市雪卡毒素食物中毒事件分析

目的:了解引起雪卡毒素中毒发生的原因、临床表现、流行病学特征,以更好地预防雪卡毒素中毒事件的发生。方法:统计分析2004～2006年度食物中毒调查报告及深圳市预防疾病控制中心的食物中毒资料。结果:2004～2006年共发生由进食苏眉、东升斑引发的雪卡毒素中毒共7事件,中毒人数96人,无死亡病例,占全市食物中毒总数的8.9%。结论:加强深海鱼类的管理,认识深海珊瑚鱼含有“雪卡”毒素的毒性,建立预防措施。

雪卡毒素及其产毒底栖甲藻的研究现状与展望

雪卡毒素(Ciguatoxins,CTXs)是一种高度氧化的环状聚醚梯类毒素,主要由冈比亚藻(Gambierdiscus)和福氏藻(Fukuyoa)两个属的底栖甲藻的一些产毒种类的株系产生。毒素通过海洋食物链在珊瑚礁鱼类中进行生物转化和积累,可引起常见的非细菌性海产中毒——雪卡毒素中毒(Ciguatera Poisoning,CP),食用被CTXs污染的鱼类会引起消费者产生胃肠道、心血管、神经方面的症状甚至导致死亡,但目前雪卡毒素中毒在全球引发的关注度与重视度不足。然而受全球气候变化和人类活动的影响,底栖甲藻在全球扩张趋势明显,特别是在亚洲地区,雪卡毒素中毒事件频繁爆发,雪卡毒素中毒对人类健康和生态系统健康构成了重大威胁。本文重点综述了产雪卡毒素底栖甲藻的种类多样性、化学多样性、生理生态学研究、以及毒素的生物合成机制与生物转化和累积方面的研究,并探讨了亚洲地区作为雪卡毒素潜在的爆发地点未来值得研究的领域以更好地保障亚洲海域的生态安全及居民健康。

一起雪卡毒素中毒事件中裸胸鳝毒性的研究

目的研究厦门一起引发食物中毒的裸胸鳝毒性及种类,以预防雪卡毒素中毒。方法对中毒事件进行流行病学调查,采集裸胸鳝样品共5份,采用小鼠生物法、雪卡毒素免疫膜检测试剂盒检测毒性大小,高效液相色谱-串联质谱法测定太平洋雪卡毒素(P-CTX-1),同时提取中毒鱼肉组织中的mtDNA,PCR技术扩增细胞色素b(Ctyb)后测序鉴定中毒鱼种。结果小鼠生物法试验检测5份样品,鱼肉毒性为无毒性(ND)～0.052 MU/g,内脏毒性为ND～0.23 MU/g;高效液相色谱-串联质谱法未检出P-CTX-1。5种鱼种经鉴定均为裸胸鳝属(Gymnothorax),其中中毒鱼种经基因测序为波纹裸胸鳝(Gymnothorax undulates)。结论引发该起食物中毒的是一种含有雪卡毒素的波纹裸胸鳝。