Epidemiology Of Childhood Viral Diarrhea

在世界范围内，胃肠道感染和腹泻疾病导致严重的发病率和死亡率，每年约有400万人死亡。大多数感染发生在生活在发展中国家的婴儿和儿童中。目前，最常见的病原体是轮状病毒。最近，肠道腺病毒、星状病毒、诺沃克病毒和其他杯状病毒在儿童腹泻疾病发病机制中的作用得到了进一步的澄清。分支机构调查人员正在评估这些病毒在埃及儿童群体中作为腹泻原因的作用，这些儿童接受了为期三年的监测。这些信息应有助于制定预防这些病毒感染的措施，包括开发和未来评估候选疫苗。结果显示，与星状病毒感染相关的腹泻与轮状病毒感染(每人每年0.19例)一样常见，两种病毒都被发现是致病的。轮状病毒腹泻和星状病毒腹泻的严重脱水发生率分别为24%和17%。除了婴儿期的母乳喂养外，没有发现其修改可能控制轮状病毒或星状病毒感染引起的腹泻疾病的潜在危险因素。这一观察，再加上之前的观察，即发达国家和发展中国家的儿童中与这些病毒有关的腹泻发生的频率相当，表明仅改善卫生和生活条件不太可能成为这一人群的充分预防措施。在监测的第一年发现的46株轮状病毒中，87%可分型，均为1型和2型。最常见的星状病毒血清型为HAstV-1，按频率顺序为HAstV-5、HAstV-8和HAstV-3、HAstV-6、HAstV-2。在确定星状病毒腹泻是否与后续疾病发病率降低相关时，有证据表明HAstV-1同型免疫而不是异型免疫提供了保护。由于38%的星状病毒腹泻发生在6个月以下的婴儿中，候选星状病毒疫苗必须在生命的早期就提供免疫力。

Worldwide, gastrointestinal infections and diarrheal diseases result in significant morbidity and mortality with approximately four million deaths each year. The majority of infections occur in infants and children living in developing nations. Currently, the most common etiologic agents are the rotaviruses. More recently, the role for enteric adenoviruses, astroviruses, Norwalk virus and other caliciviruses in the pathogenesis of childhood diarrheal diseases has received further clarification. Branch investigators are evaluating the role of these viruses as causes of diarrhea in a population-based cohort of Egyptian children who were monitored for a period of three years. This information should help in the development of preventive measures against infection by these viruses, including the development and future evaluation of candidate vaccines. Results showed diarrhea associated with astrovirus infection to be as common as rotavirus infection (0.19 episodes per person-year) and both viruses were found to be pathogenic. Severe dehydration was observed in 24% of the cases of rotavirus diarrhea and 17% of the cases of astrovirus diarrhea. Other than breastfeeding during infancy, no potential risk factors whose modification might control diarrheal disease due to rotavirus or astrovirus infection were identified. This observation, coupled with previous observations that diarrhea associated with these viruses occurs with comparable frequency among children in both developed and developing countries, suggest that improvements in hygiene and living conditions alone are unlikely to be sufficient preventive measures in this population. Of the 46 rotavirus strains identified during the first year of surveillance, 87% were typeable, and all were serotypes 1 and 2. The most frequent astrovirus serotype was HAstV-1 and in order of decreasing frequency HAstV-5, HAstV-8 and HAstV-3, HAstV-6, HAstV-2. In determining whether astrovirus diarrhea was associated with a reduced incidence of subsequent disease, there was evidence to suggest that HAstV-1 homotypic immunity, but not heterotypic immunity, conferred protection. Since 38% of the incidence of astrovirus diarrhea occured in infants less that 6 months of age, a candidate astrovirus vaccine would have to confer immunity very early in life.