Study of infectious intestinal disease in England: rates in the community,presenting to general practice, and reported to national surveillance

Objective To establish the incidence and aetiology of infectious intestinal disease in the community and presenting to general practitioners. Comparis on with incidence and aetiology of cases reaching national laboratory based surveillance. Design Population based community cohort incidence study; general practice based incidence studies, and case linkage to national laboratory surveillan ce. Setting 70 general practices throughout England. Participants 459975 patients served by the practices. Community surveillanc e of 9776 randomly selected patients. Main outcome measures Incidence of infectious intestinal disease in communi ty and reported to general practice. Results 781 cases were identified in the community cohort, giving an incide nce of 19.4/100 person years (95% confidence interval 18.1 to 20.8). 8770 c ases presented to general practice (3/3/100 person years (2.94 to 3.75)). O ne case was reported to national surveillance for every 1.4 laboratory iden tifications, 6.2 stools sent for laboratory investigation, 23 cases present ing to general practice, and 136 community cases. The ratio of cases in the community to cases reaching national surveillance was lower for bacterial pathogens (salmonella 3.2:1, campylobacter 7.6:1) than for viruses (rotavir us 35:1, small round structured viruses 1562:1). There were many cases for which no organism was identified. Conclusions Infectious intestinal disease occurs in 1 in 5 people each year , of whom 1 in 6 presents to a general practitioner. The proportion of case s not recorded by national laboratory surveillance is large and varies wide ly by microorganism. Ways of supplementing die national laboratory surveill ance system for infectious intestinal diseases should be considered.