[1] Univ Otago, Dept Pathol, Christchurch, New Zealand
[2] Canterbury Hlth Labs, Microbiol Unit, Christchurch, New Zealand
[3] Johns Hopkins Bloomberg Sch Publ Hlth, Dept Int Hlth, Baltimore, MD USA
[4] KEMRI Wellcome Trust Res Programme, Kilifi, Kenya
[5] Univ Oxford, Nuffield Dept Clin Med, Oxford, England
[6] Johns Hopkins Sch Med, Div Infect Dis, Dept Pediat, Baltimore, MD USA