[1] Univ Texas Southwestern Med Ctr, Dept Pediat, Div Cardiol, Dallas, TX 75390 USA
[2] Univ Texas Southwestern Med Ctr, Dept Pathol, Dallas, TX USA
[3] Univ Washington, Dept Lab Med, Mol Virol Lab, Seattle, WA 98195 USA
[4] Univ Wurzburg, Dept Microbiol, Wurzburg, Germany