Absence of norovirus contamination in shellfish harvested and commercialized in the Northeast coast of Brazil

Norovirus (NoV) is the main cause of gastroenteritis outbreaks worldwide. Although NoV spreads mainly from person to person, it is estimated that a large proportion of NoV outbreaks are caused by foodborne transmission. Bivalve mollusks are one of the most important foods involved in NoV transmission to humans. Little is known about NoV prevalence in shellfish harvested and commercialized in Brazil. The aim of this study was to map, for the first time, the distribution of NoV contamination in oysters and mussels harvested and commercialized in the coast of Pernambuco state, northeast Brazil. A total of 380 mollusks (260 oysters and 120 mussels) were collected between February and August 2017 either directly from harvesting areas or obtained from beach vendors at 17 sites in Pernambuco. Samples were processed and tested for NoV contamination using a SYBR Green real-time PCR assay. All samples were negative for NoV GI or GII contamination, suggesting a low risk of NoV contamination from this food source during the study period. Additional surveys in different areas of the Brazilian coast are warranted to monitor the risk of NoV infection upon seafood consumption.

诺如病毒（Norovirus, NoV）是全球范围内引发胃肠炎暴发的首要致病原。尽管诺如病毒主要通过人际接触传播，但据估算，较大比例的诺如病毒暴发事件由食源性传播引发。双壳类软体动物是介导人类感染诺如病毒的关键食物载体之一。目前学界对巴西境内捕捞及商业化销售的贝类中诺如病毒的流行态势仍知之甚少。本研究首次针对巴西东北部伯南布哥州沿岸地区捕捞并商业化销售的牡蛎与贻贝中的诺如病毒污染分布情况开展调研。研究于2017年2月至8月期间，在伯南布哥州的17个采样点，直接从捕捞作业区或海滩摊贩处采集了共计380份软体动物样本（其中260份为牡蛎，120份为贻贝）。采用SYBR Green实时荧光定量聚合酶链反应（real-time PCR）检测法对样本进行诺如病毒污染检测后发现，所有样本的诺如病毒GI型与GII型检测结果均为阴性，表明本研究周期内，该类海产品引发诺如病毒感染的风险较低。建议在巴西沿海不同区域开展后续监测调研，以持续评估食用海产品导致诺如病毒感染的潜在风险。