SUMMARY In a prospective one year study, comprising children with acute gastroenteritis admitted to hospital or treated as outpatients, the clinical and laboratory features of rotavirus diarrhoea (168 cases) were compared with those of enteric adenovirus (32 cases), bacterial (42), mixed (16), and non-specific (135) infections. The rotavirus disease was remarkably consistent, with a sudden onset of vomiting, a high frequency of fever and dehydration, and a mean duration of diarrhoea of 5-9 days. Outpatients excreting rotavirus had a similar but milder illness, mainly on account of less pronounced vomiting. The predominant symptom of enteric adenoviruses was long lasting diarrhoea (mean 10-8 days). Abdominal pain, bloody stools, prolonged diarrhoea (mean 14*1 days), leucocytosis, and a raised erythrocyte sedimentation rate strongly suggested a bacterial aetiology. Mixed infections caused longer lasting diarrhoea (mean 8-0 days) than rotavirus alone, but the severity of the illness was not increased. The clinical features of infection with unidentified pathogens most resembled those of bacterial infections. Respiratory symptoms were not significantly associated with any particular pathogen. Hypernatraemia and complications were uncommon.This study showed that the clinical features of gastroenteritis with rotavirus, enteric adenoviruses, and bacteria each exhibited patterns that could guide the experienced clinician to a presumptive diagnosis.

The physical nature of small air ions is well established and it is recognized that they can produce a variety of biological effects. However, in only a few instances have any underlying biochemical changes been detected. Theoretically, one can consider the hydrated superoxide radical anion (O2) (H2O)n with n congruent to 4-8 as a likely candidate for a biologically active species of negative air ion. The chemical and biological reactivity of superoxide is high and includes a leading role in bacterial killing caused by radiation, in which superoxide dismutase (SOD), an enzyme that catalyses the reaction: O2 + O2 +2H leads to H2O2 +O2 protected markedly. Other studies have also demonstrated the bactericidal effect of O2 (refs 9-11). Inasmuch as the bactericidal action of small negative air ions has been repeatedly confirmed, we decided to test for the involvement of O2 in this phenomenon by evaluating the protective effect of SOD. Our results show strong O2 involvement in negative air ion bacterial kill.