[1] ALL INDIA INST MED SCI, DEPT PEDIAT, DIV GASTROENTEROL & ENTERIC INFECT, NEW DELHI 110016, INDIA
[2] NATL BACTERIOL LAB, DEPT VIROL, S-10521 STOCKHOLM, SWEDEN
[3] KAROLINSKA INST, ST GORANS CHILDRENS HOSP, DEPT PEDIAT, S-11281 STOCKHOLM, SWEDEN
[4] UNIV DELHI, UP CHEST INST, DEPT RESP VIROL, DELHI 110007, INDIA