what does anne mean when she say ,invasion fever is mounting daily

"Invasion fever is mounting daily throughout the country"

This quote can be found in Anne's diary entry from February 1944. It was at this time, the family (and other occupants of the annex) were made aware that the Allied troops were were readying themselves to invade and liberate Europe. Unfortunately, the allies didn't arrive in Holland until March of 1945 (the They invaded Normandy in June 1994). The "fever" was the anticipation of their arrival.