Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas.
Department of Medicine.
Curr Opin Infect Dis. 2019 Aug;32(4):348-355. doi: 10.1097/QCO.0000000000000557.
The majority of norovirus outbreaks in the United States occur in healthcare facilities. With the growing population of immunocompromised hosts who are in frequent contact with healthcare facilities, norovirus is not only a threat to hospitals and nursing homes but also to these individuals. This review summarizes the impact of norovirus infection on healthcare facilities and immunocompromised hosts.
The natural history of norovirus infection in immunocompromised individuals remains poorly understood. Although host immune responses play a critical role in reducing duration of viral shedding and viral load in norovirus-infected individuals, why some immunocompromised patients spontaneously recover while others develop a chronic and protracted course of illness remains unclear. Norovirus outbreaks occur in healthcare facilities because the virus is highly contagious, resistant to disinfection and efficiently transmitted. The use of real-time metagenomic next-generation sequencing and phylogenetic analyses has provided valuable information on transmission patterns in complex hospital-associated norovirus outbreaks. The development of human intestinal enteroid cultures enables the determination of effectiveness of disinfectants against human noroviruses, circumventing the validity questions with surrogate virus models due to differences in susceptibility to inactivation and disinfectants.
Metagenomics next-generation sequencing can enhance our understanding of norovirus transmission and lead to more timely mitigation strategies to curb norovirus outbreaks in healthcare facilities. With new in-vitro cultivation methods for human noroviruses, candidate vaccines and effective antivirals could be available in the near future.
美国大多数诺如病毒暴发发生在医疗机构中。随着经常接触医疗机构的免疫功能低下宿主人群的不断增加，诺如病毒不仅对医院和疗养院构成威胁，也对这些个体构成威胁。本文综述了诺如病毒感染对医疗机构和免疫功能低下宿主的影响。
免疫功能低下个体中诺如病毒感染的自然史仍知之甚少。尽管宿主免疫反应在减少诺如病毒感染个体的病毒脱落和病毒载量方面起着至关重要的作用，但为什么有些免疫功能低下的患者会自行康复，而有些患者则会出现慢性和迁延性疾病，目前仍不清楚。诺如病毒在医疗机构中暴发是因为该病毒具有高度传染性、对消毒有抵抗力并且能够有效传播。实时宏基因组下一代测序和系统发育分析的应用为复杂医院相关诺如病毒暴发的传播模式提供了有价值的信息。人类肠道类器官培养的发展使我们能够确定消毒剂对人类诺如病毒的有效性，避免了由于对失活和消毒剂的敏感性差异导致替代病毒模型的有效性问题。
宏基因组下一代测序可以增进我们对诺如病毒传播的理解，并促使我们制定更及时的缓解策略，以遏制医疗机构中的诺如病毒暴发。随着针对人类诺如病毒的新的体外培养方法的出现，候选疫苗和有效的抗病毒药物可能在不久的将来问世。
