[1] DALHOUSIE UNIV,DEPT MICROBIOL,HALIFAX B3H 4H2,NS,CANADA
[2] DALHOUSIE UNIV,DEPT COMMUNITY HLTH & EPIDEMIOL,HALIFAX B3H 4H2,NS,CANADA
[3] DALHOUSIE UNIV,DEPT PEDIAT,HALIFAX B3H 4H2,NS,CANADA
[4] IZAAK WALTON KILLAM HOSP CHILDREN,HALIFAX B3J 3G9,NS,CANADA
[5] DALHOUSIE UNIV,DEPT MED,HALIFAX B3H 4H2,NS,CANADA