Seasonal Variations in Norovirus Outbreaks Among Passengers and Crew members on Cruise Ships in Europe: A narrative review

Abstract

Background: Norovirus, a Ribonucleic acid (RNA) virus of the family Caliciviridae, is a human enteric pathogen that is recognized as the leading cause of acute gastroenteritis in children and adults. Worldwide norovirus- Acute gastroenteritis (AGE) outbreaks can occur in a variety of settings, including cruise ships. Seasonal variations may have impacts in outbreaks patterns and outcomes. Commonly, outbreaks of norovirus can occur in restaurants, at tourist destinations and especially aboard cruise ships. Climate change has been shown to influence the incidence and spread of norovirus infections. Understanding norovirus outbreak impact factors is important in preventing major disease and complication, and maintaining the tourism industry among major cruise ships. This study aims to investigate how seasonal variations impact on the spread of infection caused by norovirus outbreaks among passengers and crew on cruise ships in Europe. Methods: A comprehensive literature review was performed to identify relevant literature to explain how seasonal variations impact the spread of norovirus aboard cruise ships in Europe. The target population for this study was passengers and crew aboard luxury cruise liners in Europe. The inclusion criteria for articles included studies published between 01 January 2006 and 31 December 2017 that addressed norovirus outbreaks and the target population. A total of ten (10) articles were reviewed by one author, and five articles were selected for final review and appraisal process. Results: Overall, a total of 112 norovirus outbreaks on 73 vessels had been reported in the studies between January 2006 and December 2013, for a total of 2,848 days at risk. There were a total of 880586 passengers and crew aboard the vessels during this period of time. Norovirus outbreaks showed a peak in summer months. Among the 5 studies analyzed, 4 norovirus outbreaks occurred in seasonal (October-April) and 41 outbreaks occurred in off seasonal months (May-September). Conclusions: This study confirms the importance of identifying the seasonal data norovirus outbreaks on cruise ships in Europe and, at the same time, confirms and compiles the data on a large number of norovirus outbreaks in Europe on passenger’ cruise ships. At present, more data and published studies are needed to confirm an increase in norovirus outbreaks on cruise ships due to seasonal variation and climate. Key words: Cruise ships, gastroenteritis, viral pathogens, outbreak, epidemiology diseases in EU