Global prevalence of norovirus gastroenteritis after emergence of the GII.4 Sydney 2012 variant: a systematic review and meta-analysis.

Introduction: Norovirus is widely recognized as a leading cause of both sporadic cases and outbreaks of acute gastroenteritis (AGE) across all age groups. The GII.4 Sydney 2012 variant has consistently prevailed since 2012, distinguishing itself from other variants that typically circulate for a period of 2-4 years. Objective: This review aims to systematically summarize the prevalence of norovirus gastroenteritis following emergence of the GII.4 Sydney 2012 variant. Methods: Data were collected from PubMed, Embase, Web of Science, and Cochrane databases spanning the period between January 2012 and August 2022. A meta-analysis was conducted to investigate the global prevalence and distribution patterns of norovirus gastroenteritis from 2012 to 2022. Results: The global pooled prevalence of norovirus gastroenteritis was determined to be 19.04% (16.66-21.42%) based on a comprehensive analysis of 70 studies, which included a total of 85,798 sporadic cases with acute gastroenteritis and identified 15,089 positive cases for norovirus. The prevalence rate is higher in winter than other seasons, and there are great differences among countries and age groups. The pooled attack rate of norovirus infection is estimated to be 36.89% (95% CI, 36.24-37.55%), based on a sample of 6,992 individuals who tested positive for norovirus out of a total population of 17,958 individuals exposed during outbreak events. Conclusion: The global prevalence of norovirus gastroenteritis is always high, necessitating an increased emphasis on prevention and control strategies with vaccine development for this infectious disease, particularly among the children under 5 years old and the geriatric population (individuals over 60 years old).

Epidemiological characteristics of Kala-azar disease in China, during 2005-2015 / 中华流行病学杂志

Objective To explore the epidemiological characteristics of Kala-azar disease in China from 2005 to 2015,to provide evidence for the development of related control and measurement strategies.Methods Data was obtained from Disease Reporting Information System of China CDC,to compare factors on type,distribution,peak season and the age of onset of the cases.Results Epidemic of Kala-azar had been persistent in China.Number of the reported cases declined in Sichuan and Gansu provinces but two outbreaks had occurred in Xinjiang Uygur autonomous region.The epidemic was confined in few areas.The reported cases were mainly from Xinjiang,Gansu and Sichuan,with the total cases in these three provinces accounted for 95.29％ of all the cases seen in the country.The main peak season was from October to November,followed by April.There were significant differences seen in the age distributions of canine Kala-azar,anthroponotic Kala-azar and wildlife-oriented Kala-azar (P＜0.05) cases.Majority of the cases involved under 3-year-olds,with peak age in under 1-year-olds for wildlife-oriented Kala-azar.For anthroponotic and canine Kala-azar cases,most of them were seen among the under 10 years old,with the peak among the 5-year-olds.Conclusions In recent years,Kala-azar had been seen endemic and persistent,in the mid-west regions of China,but with different epidemiological characteristics.Further study on Kala-azar should be carried on to include appropriate measurements and strategies,according to the features of the disease,in the mid-western areas of China.

Epidemiological characteristics of Kala-azar disease in China, during 2005-2015 / 中华流行病学杂志

Objective To explore the epidemiological characteristics of Kala-azar disease in China from 2005 to 2015,to provide evidence for the development of related control and measurement strategies.Methods Data was obtained from Disease Reporting Information System of China CDC,to compare factors on type,distribution,peak season and the age of onset of the cases.Results Epidemic of Kala-azar had been persistent in China.Number of the reported cases declined in Sichuan and Gansu provinces but two outbreaks had occurred in Xinjiang Uygur autonomous region.The epidemic was confined in few areas.The reported cases were mainly from Xinjiang,Gansu and Sichuan,with the total cases in these three provinces accounted for 95.29％ of all the cases seen in the country.The main peak season was from October to November,followed by April.There were significant differences seen in the age distributions of canine Kala-azar,anthroponotic Kala-azar and wildlife-oriented Kala-azar (P＜0.05) cases.Majority of the cases involved under 3-year-olds,with peak age in under 1-year-olds for wildlife-oriented Kala-azar.For anthroponotic and canine Kala-azar cases,most of them were seen among the under 10 years old,with the peak among the 5-year-olds.Conclusions In recent years,Kala-azar had been seen endemic and persistent,in the mid-west regions of China,but with different epidemiological characteristics.Further study on Kala-azar should be carried on to include appropriate measurements and strategies,according to the features of the disease,in the mid-western areas of China.