Doubts hang over source of bird flu spread.
Butler
Declan
D
D000349:Africa / Q000453:epidemiology; D025041:Animal Migration; D000818:Animals; D000835:Animals, Wild / Q000502:physiology / Q000821:virology; D001717:Birds / Q000502:physiology / Q000821:virology; D002353:Carrier State / Q000635:transmission / Q000662:veterinary / Q000821:virology; D004197:Disease Reservoirs / Q000662:veterinary* / Q000821:virology*; D005060:Europe / Q000453:epidemiology; D006801:Humans; D053124:Influenza A Virus, H5N1 Subtype / Q000302:isolation & purification*; D005585:Influenza in Birds / Q000453:epidemiology* / Q000635:transmission / Q000821:virology*; D011200:Poultry / Q000502:physiology / Q000821:virology