Risk Assessment in Shellfish-Borne Outbreaks of Hepatitis A
Risk Assessment in Shellfish-Borne Outbreaks of Hepatitis A
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DOI：
10.1128/aem.01177-09
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发表时间：
2009-12-01
影响因子：
4.4
通讯作者：
Bosch, Albert
中科院分区：
文献类型：
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作者：
Pinto, Rosa M.;Costafreda, M. Isabel;Bosch, Albert
在本工作中，我们旨在确定涉及两次肝炎暴发的进口冷冻凤尾蛤的甲型肝炎病毒（HAV）数量及其对人类健康的风险之间的关系。由于HAV的不可培养性，采用标准化的TaqMan实时逆转录pcr控制病毒/核酸提取和酶效率来计算导致肝炎病例的蛤的暴露剂量。然后根据埃可病毒12的剂量-反应模型，采用HAV数字来计算感染的风险。食用稍微煮熟的蛤蜊后估计的感染风险与实际发病率相符。我们的数据显示，对双壳类样品的前瞻性监测可能无法防止疫情的发生，因为在与病例直接相关的44%的样品中检测到甲肝病毒，但在从进口商随机收集的属于同一批次的样品中未检测到甲肝病毒。然而，在收获区观察到甲型肝炎病例的流行与蛤中甲肝病毒阳性分离之间存在相关性，这表明需要识别和预防危害，而不是依靠成品的随机抽样来确保安全。然而，当有证据表明，在排放到贝类养殖床的潜在污染源中，病毒污染已超过临界限度时，应对贝类进行定量病毒学分析，以解决质量保证和质量控制要求。这项工作提供了暴发中贝类甲肝病毒准确水平的第一个证据，可用于风险评估目的。
In the present work, we aimed at determining the relationship between the hepatitis A virus (HAV) numbers in imported frozen coquina clams involved in two hepatitis outbreaks, as well as the risk for human health. Due to HAV unculturability, a standardized TaqMan real-time reverse transcription-PCR controlling the virus/nucleic acid extraction and enzyme efficiencies was employed to figure the exposure dose for clams responsible for hepatitis cases. HAV numbers were then employed to figure the risk of infection based on a dose-response model for echovirus 12. The estimated risk of infection after consumption of lightly cooked clams matched actual attack rates. Our data show that prospective monitoring of bivalve samples may fail to prevent the occurrence of outbreaks, since HAV was detected in 44% of samples directly associated with cases but was undetectable in samples that were randomly collected from the importers and belonged to the same batches. A correlation was nevertheless observed between the prevalence of hepatitis A cases in the harvesting areas and positive HAV isolation in clams, which points to the need to identify and prevent hazards rather than relying on random sampling of finished products to ensure safety. However, when evidence shows that a critical limit of viral contamination has been exceeded in the potential sources of contamination discharging into the shellfish-growing beds, quantitative virological analysis addressing quality assurance and quality control requirements should be performed with the bivalves. This work provides the first evidence of accurate HAV levels in shellfish involved in outbreaks that could be of use for risk assessment purposes.