That is no longer thought to be true. Instead, it may be that cuticular hydrocarbons on the potential new host signal the age of the bee to the mite. The tracheal tubes can become very cluttered and eventually blocked. However, it is not clear that this blockage is what kills the bees. The flow of oxygen does not appear to be inhibited.
Infested bees live and work normally, though their lives are shortened.
The precise cause of death remains uncertain. The mite population is cyclical. There is a fall build up, a winter peak, and a summer crash. This is opposite to the normal honey bee population cycle in which there is a spring buildup, a summer peak, and a winter decline. A good queen bee will outproduce the mites in the spring and summer, getting ahead of them and easing the mite problem for the colony.