[1] Univ Alabama, Dept Pediat, Birmingham, AL 35238 USA
[2] All India Inst Med Sci, Dept Microbiol, New Delhi, India
[3] All India Inst Med Sci, Comprehens Rural Hlth Serv Project, Ctr Community Med, New Delhi, India
[4] Univ Alabama, Dept Epidemiol, Birmingham, AL 35238 USA
[5] Univ Alabama, Dept Maternal & Child Hlth, Birmingham, AL 35238 USA
[6] Univ Alabama, Dept Microbiol, Birmingham, AL 35238 USA