Risk factors for intussusception in infants in Vietnam and Australia: Adenovirus implicated, but not rotavirus

Objective This study aimed to investigate risk factors for the development of intussuseeption in infants in a developing country with a suspected high incidence and in a developed country with a low incidence. Study design A prospective case-control study of infants < 2 years of age with idiopathic intussusception confirmed by air enema or surgery was conducted at the National Hospital of Paediatrics (NHP), Vietnam (n = 533) and the Royal Children's Hospital (RCH), Australia (n = 51). Diagnosis was validated in a subset (84% NHP; 67% RCH) by an independent blinded radiologist. Risk factor assessment was performed using a standardized questionnaire. Stool specimens were assayed for bacterial, viral, and parasitic agents. Results The incidence of intussusception in Vietnam was 302/100,000 in infants < 1 year of age (95% CI: 258-352), substantially higher than in Australia (71/100,000). A strong association with adenovirus infection was observed at both sites (cases positive at NHP: 34%, OR 8.2; cases positive at RCH: 40%, OR 44). No association was identified between intussusception and rotavirus, other enteric pathogens, oral polio vaccine, feeding practices, or living conditions. Conclusions The incidence of intussuseeption in infants was markedly higher in Vietnam than in Australia. A strong association between adenovirus infection and intussusception was identified at both sites suggesting that adenovirus may play a role in the etiology of intussuseeption.