Epidemiology Of Childhood Viral Diarrhea

在世界范围内，胃肠道感染和消化道疾病导致显著的发病率和死亡率，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、诺瓦克病毒和其他杯状病毒在儿童腹泻病发病机制中的作用得到了进一步的阐明。分支研究人员正在评估这些病毒作为腹泻原因的作用，这些病毒在一个以人群为基础的埃及儿童队列中进行了为期三年的监测。这些信息应有助于制定预防这些病毒感染的措施，包括候选疫苗的开发和未来评估。结果显示，与星状病毒感染相关的腹泻与轮状病毒感染一样常见（每人每年0.19次），并且发现两种病毒都是致病性的。在24%的轮状病毒腹泻病例和17%的星状病毒腹泻病例中观察到严重脱水。除婴儿期母乳喂养外，未发现任何潜在的危险因素，其改变可能控制轮状病毒或星状病毒感染引起的腹泻。这一观察结果，再加上以前的观察结果，即与这些病毒相关的腹泻在发达国家和发展中国家的儿童中发生的频率相当，表明仅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。在第一年监测期间发现的46种轮状病毒株中，87%可分型，且均为血清型1和2。最常见的星状病毒血清型是HAstV-1，并且按照频率降序为HAstV-5、HAstV-8和HAstV-3、HAstV-6、HAstV-2。在确定星状病毒腹泻是否与随后疾病的发病率降低相关时，有证据表明HAstV-1同型免疫而非异型免疫赋予保护作用。由于38%的星状病毒腹泻发生在6个月以下的婴儿中，因此候选星状病毒疫苗必须在生命早期赋予免疫力。

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.