A patient in a Missouri hospital undergoing treatment for influenza yielded an H5 virus as confirmed by the Centers for Disease Control and Prevention.  There was no apparent known contact with food animals or poultry prior to onset of symptoms.  There was no evidence of human-to-human transmission to contacts. The patient made an uneventful recovery.

This sporadic case was identified following routine hospital assay that identified influenza A but was negative for seasonal influenza virus subtypes. This apparent inconsistency resulted in  submission of the virus to the CDC.

The case raises a number of questions focussing on the source of the infection (pet cats or birds? consumption of raw milk? occupational exposure? or factors as yet identified?) It would be important to determine whether the virus isolated from the patient was homologous with the mammalian adapted H5N1 B3.13 in dairy cows and rodents. H5 influenza resulting in hospitalization requires expedient and thorough epidemiologic investigation by a CDC team. Transparency with prompt reporting of relevent information.  Epidemics start with a few cases and are easier to contain at an early stage in an outbreak.