Stephan Talty's 'The illustrious dead':
When Napoleon invaded Russia in 1812, typhus ravaged his army, killing
hundreds of thousands and ensuring his defeat, according to this
breathless combination of military and medical history. After
summarizing the havoc this disease wreaked on earlier armies and
sketching Napoleon's career, the book describes his invasion of Russia
with more than 600,000 men. Almost immediately typhus struck. Infected
lice excrete the microbe in their feces, and victims acquire the disease
by scratching the itchy bite. Talty describes
the effects in graphic detail: severe headache, high fever, delirium,
generalized pain and a spotty rash. Death may take weeks, and fatalities
approached 100% among NapoleonÖs increasingly debilitated, filthy,
half-starved soldiers. Talty makes a good case that it was typhus, not
General Winter, that crushed Napoleon. Readers should look elsewhere for
authoritative histories of NapoleonÖs wars and of infectious diseases,
but Talty delivers a breezy, popular account of a gruesome campaign,
emphasizing the equally gruesome epidemic that accompanied it. (Publisher's Weekly review).
I haven't read this one but I think I'll add it to my reading list.
for something a little more immediately accessible you can read Insects,disease, and military history: the Napoleonic campaigns and historical perception. The version online is adapted from a paper of the same name in the American Entomologist. (1995) 41:147-160.