Green’s Dictionary of Slang

(US) yellow fever.

1862		N.O. Dly Crescent (LA) 16 Apr. 1/4: Talking about Bronze John, yellow fever and vomito, we are reminded of the latest intelligence from Havana [...] twenty-seven cases of yellow fever or vomito.
1869		‘South-Western Sl.’ in Overland Monthly (CA) Aug. 130: As for diseases, ‘Bronze John’ is pretty well known for yellow fever.
1878		Bossier Banner (Bellevue, LA) 5 Dec. 4/1: A King is Bronze John and his steed is Death — / [...] / Bronze John of the saffron plume.
1888		Dly Times (Richmond, VA) 11 Sept. 1/3: ‘Bronze John’ [...] Two deaths from yellow fever were reported .
1905		Lafayette Advertiser (LA) 6 Sept. 4/5: What will Gulfport be without these distinguished citizens to defeat [...] Bronze John [...] The ‘bold soldier boys’ [...] will not go to Gulfport [...] to repel and baffle the invasion of yellow fever.