NEJM：诺瓦克病毒成美国未满5岁儿童急性胃肠炎主因

　　美国疾病预防控制中心（CDC）病毒性疾病部的Daniel C. Payne博士等对在美国医疗机构就诊的未满5岁儿童急性胃肠炎发病情况进行调查后发现，诺瓦克病毒为发病主要因。另一方面，因轮状病毒就诊的患者减少。详情近期发表于《新英格兰医学杂志》。

　　流行病学家Payne博士等2009和2010年的调查显示，因诺瓦克病毒就诊的乳儿和幼儿每年约为100万人，随之而来的是每年数亿美元医疗费。

　　诺瓦克病毒感染力强，美国每年有2100万人因诺瓦克病毒感染而罹患急性胃肠炎，其中约800万人死亡。乳幼儿和高龄者容易感染和加重。诺瓦克病毒主要感染那些与感染者亲密接触的看护者。

Norovirus and Medically Attended Gastroenteritis in U.S. Children
Background
Cases of rotavirus-associated acute gastroenteritis have declined since the introduction of rotavirus vaccines, but the burden of norovirus-associated acute gastroenteritis in children remains to be assessed.
Methods
We conducted active surveillance for laboratory-confirmed cases of norovirus among children younger than 5 years of age with acute gastroenteritis in hospitals, emergency departments, and outpatient clinical settings. The children resided in one of three U.S. counties during the years 2009 and 2010. Fecal specimens were tested for norovirus and rotavirus. We calculated population-based rates of norovirus-associated acute gastroenteritis and reviewed billing records to determine medical costs; these data were extrapolated to the U.S. population of children younger than 5 years of age.
Results
Norovirus was detected in 21% of young children (278 of 1295) seeking medical attention for acute gastroenteritis in 2009 and 2010, with norovirus detected in 22% (165 of 742) in 2009 and 20% (113 of 553) in 2010 (P=0.43). The virus was also detected in 4% of healthy controls (19 of 493) in 2009. Rotavirus was identified in 12% of children with acute gastroenteritis (152 of 1295) in 2009 and 2010. The respective rates of hospitalization, emergency department visits, and outpatient visits for the norovirus were 8.6, 146.7, and 367.7 per 10,000 children younger than 5 years of age in 2009 and 5.8, 134.3, and 260.1 per 10,000 in 2010, with an estimated cost per episode of $3,918, $435, and $151, respectively, in 2009. Nationally, we estimate that the average numbers of annual hospitalizations, emergency department visits, and outpatient visits due to norovirus infection in 2009 and 2010 among U.S. children in this age group exceeded 14,000, 281,000, and 627,000, respectively, with more than $273 million in treatment costs each year.
Conclusions
Since the introduction of rotavirus vaccines, norovirus has become the leading cause of medically attended acute gastroenteritis in U.S. children and is associated with nearly 1 million health care visits annually. (Funded by the Centers for Disease Control and Prevention.)