Epidemiology Of Childhood Viral Diarrhea

在世界范围内，胃肠道感染和腹泻疾病导致大量发病率和死亡率，每年约有400万人死亡。大多数感染发生在发展中国家的婴儿和儿童中。目前，最常见的病原是轮状病毒。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。分支调查人员正在对以人群为基础的埃及儿童队列进行为期三年的监测，评估这些病毒作为腹泻病因的作用。这些信息应有助于制定预防这些病毒感染的措施，包括开发和今后评价候选疫苗。结果表明，星状病毒感染与轮状病毒感染相关的腹泻同样常见（每人年0.19次），两种病毒均为致病性。24%的轮状病毒腹泻病例和17%的星状病毒腹泻病例出现严重脱水。除婴儿期母乳喂养外，没有发现可能控制轮状病毒或星状病毒感染引起的腹泻病的潜在危险因素。这一观察结果，再加上先前的观察结果，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种轮状病毒毒株中，87%可分型，均为血清1型和血清2型。最常见的星状病毒血清型为HAstV-1，其次为HAstV-5、HAstV-8、HAstV-3、HAstV-6、HAstV-2。在确定星状病毒腹泻是否与随后疾病的发生率降低相关时，有证据表明，HAstV-1同型免疫而非异型免疫具有保护作用。由于38%的星状病毒腹泻发生率发生在6个月以下的婴儿中，因此星状病毒候选疫苗必须在生命早期就赋予免疫。

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.