https://chroniclingamerica.loc.gov/lccn/sn92053240/1918-04-11/ed-1/seq-4/#date1=1918&sort=date&date2=1918&words=influenza&language=&sequence=0&lccn=&index=8&state=&rows=20&ortext=&proxtext=influenza&year=&phrasetext=&andtext=&proxValue=&dateFilterType=yearRange&page=13

The germ spreader is the enemy within. The evil lurks wherever there are people, and spew from the lungs of sufferers "belching disease as a German battery belches shells." This is an unnecessary peril and the Army Medical Corps is certain that the respiratory diseases (influenza, tuberculosis, meningitis, pneumonia) can be contained, and the war on spitting won.

Source: "Germ Spreader," Free-Trader Journal, Ottawa, Illinois, April 11, 1918.