Genotypic and Epidemiological Trends of Acute Gastroenteritis Associated with Noroviruses in China from 2006 to 2016

Abstract

There are periodical norovirus-associated acute gastroenteritis outbreaks around the world. This study aimed to analyze the molecular and epidemiological features of norovirus infections in China during 2006–2016. We extracted epidemiological data from 132 norovirus outbreaks and the norovirus genotyping for 1291 sequences in China over the past ten years. A total of 132 norovirus outbreaks (8133 cases) were reported in China, where the east and south regions were most affected [47.7% (63/132)]. The highest number of outbreaks occurred in 2015. A seasonal pattern has been observed, with a peak from November to the following March. Most of the outbreaks occurred in middle and primary schools, accounting for 28.8% (38/132), and 28.0% (37/132) of outbreaks, respectively. The dominant age group was 10 to 19 years old, responsible for 75.7% (933/1232) of cases. Generally, the dominant genotypes was GII, for 81.9% (1058/1291) of sequences. G II.4 was the predominant genotype in China from 2004 to 2014. However, the GII.17 became more prevalent starting in 2014. Norovirus-associated acute gastroenteritis increased sharply in recent years caused by the emergence of GII.17, but epidemiological features have not changed during 2006–2016. Vigilant surveillance should be strengthened to promptly detect any variation.

Prevalence of noroviruses in children hospitalized for acute gastroenteritis in Hohhot, China, 2012-2017

“…GII.4/Sydney 2012 was first identified in Australia, France, and New Zealand, and subsequently isolated in the United States, Belgium, Denmark, Scotland, Japan, and China. Of note, after 2012, the GII.4/Sydney 2012 variant was the dominant epidemic strain in Hohhot and most other regions of China, both in sporadic NV cases and NV outbreaks [19,21]. Previous studies show GII.4 usually caused epidemics in adult populations, whereas GII.3 NV was prevalent in young children and infants [45,46].…”

“…Three major clusters (I-III) and five smaller genetic lineages (A-E) have been identified in the VP1 region of GII.3 NV [13,18]. Global surveillance data over the years indicated that the majority of outbreaks of NV were caused by GII.4, but the recent NV outbreak strains in Asia were GII.2 and GII.17 [1,19,20]. Furthermore, other genotypes were co-circulating, with different epidemiological patterns in different regions [1,17].…”

“…China is a vast country, and the prevalence of NV varies by region [1,19,21,22]. However, reports and knowledge of routine sporadic NV disease in northern China have been limited.…”

“…However, reports and knowledge of routine sporadic NV disease in northern China have been limited. Furthermore, in several recent years, rare NV genotypes (GII.2, GII.6, and GII.17) have caused prevalent outbreaks in China [19,20] and other parts of Asia [23,24]. Therefore, it is important to explore the NV strains in sporadic AGE cases, which may also aid in understanding the prevalence of human NV in the population.…”

Recalibration of the Grunow–Finke Assessment Tool to Improve Performance in Detecting Unnatural Epidemics

“…No other norovirus outbreaks were reported in Beijing during the same period ( specific population : 1 point). Schools are a common site for norovirus outbreaks in China (Qin et al., ), so we scored the criterion “ geographic distribution ” as 0 points. More than 80% of cases had vomiting, nausea, and stomach pain, which were the typical symptoms of norovirus infection, no matter if it was intentionally or unintentionally caused ( clinical manifestation : 1 point).…”