This past week authorities in the Czech Republic confronted an outbreak of HPAI in a complex housing 750,000 hens.  The report notes that in the initial control phase 220,000 birds were depleted.  The report posted on the ProMED website noted that “Checks revealed the infection only in one of the houses, so the majority of the flock could be spared.”  This statement is totally at variance with experience that HPAI infection on any complex is an all-all-none situation. In the event the entire complex was subsequently depopulated with evidence of infection in all houses.

Inter-flock transmission through a single complex is inevitable based on movement of personnel and possible aerogenous transmission of virus on entrained dander and dust.  Experience among numerous outbreaks in the U. S. has demonstrated delays measured in days before the inevitable increase in mortality is evident.