Resident expert
Samuel
Crowell comments on the above:

THE DOCUMENTARY sources you have cited here are very important, because up until now the only place I have seen this claim was in Jan Karski’s Story of a Secret State,
1944, which contains the following passage on page 258
[Karski is discussing a Pole named Jan, who specializes in revenge]:

“To spread contagious diseases was Jan’s
favorite activity. He carried on his person an
astonishing collection of every type of lethal agent. He
had an attractive, specially constructed little box in
which were housed lice that bore microbes,
typhoid-bearing germs and others. I was so repelled by
this notion that I forebore to gather more specific
information. His methods, however, were well-known among
us.

He would frequent bars, enter into conversation with
German soldiers, and drink with them. Drinking was one of
Jan’s pleasures but he never let it interfere with his main objective. At the proper moment he would drop a louse bearing typhoid germs behind the collar of his German friend
[sic! He means “typhus” — the terms are frequently confused -SC]. He would drop germs into drinks. He, too, would introduce them to girls who had venereal diseases.”

I am sure that you would agree that the above, without documentary support, sounds a little outlandish.