In a report of an outbreak of highly pathogenic avian influenza in Kagoshima Prefecture, the Ministry of Agriculture stated, “Dust carrying the bird flu virus likely entered into the facilities through ventilators.”  In addition, in this case there were obvious defects in biosecurity with building contractors entering the farm without following appropriate decontamination and use of farm-supplied footwear and outer clothing.

There is a growing sentiment among poultry health professionals in the U.S. that the virus can be transmitted on dust entrained in wind entering the air inlets of houses subject to negative ventilation.  There is adequate scientific evidence to support this hypothesis.  If valid, even the most stringent biosecurity will not protect large complexes. Given the regional and seasonal endemic status of highly pathogenic avian influenza, vaccination would appear to be a necessary adjunct to biosecurity for egg-production complexes in high-risk areas. If a decision on limited regional vaccination is made then pullets reared in these areas should be vaccinated in advance of the Spring 2025 seasonal outbreaks.