Inter-Continental Patterns of HIV-1 Control: HLA and the Quest for a T Cell Vaccine

toxins A and B and possibly binary toxins. Improvements in molecular epidemiological techniques are increasingly enhancing our understanding of C. difficile. The epidemiology of C. difficile is not entirely delineated, but it is clear that the organism can be carried asymptomatically in addition to causing disease. Studies from the 1980s and 1990s have suggested that asymptomatic carriage of C. difficile is common in infants, although research into the organism as a pathogen in the paediatric population at that time was inconclusive. More recent work from North America has, however, again focused on the apparent increase in CDAD amongst children, and a prevalence of up to 20% of the hypervirulent BI/NAP1/027 strain in paediatric patients with diarrhoea who are positive for C. difficile has been reported. This strain has been responsible for epidemic outbreaks in adults over the last six years and is associated with more severe disease most likely due to increased toxin production mediated via deletions in the tcdC toxin regulator gene. This study was designed as a pilot to assess methodology for detailed molecular epidemiological investigations of C. difficile in children.