Norovirus gastroenteritis outbreaks in military units: a systematic review

Abstract

IntroductionNorovirus gastroenteritis is one of the most frequent causes of personnel unavailability in military units, being associated with significant morbidity and degradation of their operational effectiveness. The disease is usually mild but can be severe and life-threatening in young and healthy soldiers, who are prone to dehydration due to intensive daily activity. Despite its impact, the full extent of the norovirus gastroenteritis burden in military forces remains unclear. This systematic review aims to evaluate the impact and ascertain clinical and epidemiological features of norovirus outbreaks that have occurred in the military forces.MethodsThe systematic review followed the Preferred Reporting Items for Systemic Reviews and Meta-Analysis (PRISMA) guidelines and used three databases: PubMed, Scopus, and LILACs. Papers published up to 1 September 2019 were included without restrictions if they reported one or more outbreaks in the military forces on active duty, either on national territories or deployed overseas.ResultsA total of 343 papers were retrieved from the literature search. After inclusion/exclusion criteria a total of 39 eligible papers were considered. From 1988 (first reported outbreak in the military) to 2018 more than 101 norovirus outbreaks have been reported in the military, accounting for at least 24 332 cases. Secondary transmission was emphasised as the main route of norovirus transmission in the military forces, with eating outside the military setting an important route for the primary cases.ConclusionsThe present review highlights that norovirus gastroenteritis has been a burden to military troops both in combat and on peacekeeping operations. Norovirus disease has been shown to exact a substantial toll on mission readiness and operational effectiveness. It is noteworthy that the impact of norovirus outbreaks among military units is underestimated because the literature review retrieved information from the armed forces from only nine countries.

Norovirus: Facts and Reflections from Past, Present, and Future

“…Given the progress made in its detection by sensitive molecular diagnostic techniques and the introduction of the rotavirus vaccine, NoV has emerged in recent years as a leading causative agent of AGE in most locations and age groups [24][25][26][27]. It is associated with nearly 20% of all acute diarrheal cases globally, and with an estimated 685 million episodes and 212,000 deaths annually [24,28,29].…”

Immune Imprinting Drives Human Norovirus Potential for Global Spread

“…Population immunity would then determine which variants would successfully emerge and become dominant. As the most frequent cause of viral acute gastroenteritis outbreaks in the 21st century, six GII.4 norovirus variants have predominated worldwide in the past 25 years ( 18 – 20 ), resulting in significant burdens on health care, education, and military units ( 21 – 23 ). The first GII.4 variant with worldwide distribution emerged in the mid-1990s, followed by subsequent variant replacements in 2002 (circulation 2002 to 2005), 2004 (2004 to 2008), 2006 (2006 to 2011), 2009 (2009 to 2012), and 2012 (2012 to at least 2022).…”