Green’s Dictionary of Slang

influenza, a cough, thus v. tissick to cough.

1714		Stamford Mercury 9 Sept. 2/3: Bills of Moratalitry from August 24. to August 31. [...] Teeth — 21. Thrush — 1. Tissick — 2.
c.1785		‘Darby O’Gallagher’ in A. Carpenter Verse in Eng. in 18C Ireland (1998) 400: His excellent musick is good for the tisick, / It works the fair maids like a dose of jallip.
1839		Suffolk Chron. 5 Oct. 3/2: When near the Barracks, he ‘tissicked’ and spat blood.
1859		Chelmsford Chron. 29 Apr. 3/7: [B]eing able to get through the third part of a pipe of tobacco without any uneasiness except a sort of ‘tissicking’.
1876		Fifeshire Jrnl 19 Oct. 3/1: ‘[M]achine,’ the old slang term for conveyance, the modern one being ‘trap’; ‘tissick’ for ‘asthma’ [etc].
1898		Penrith Obs. 31 May 6/6: TISSICK—An epidemic. It's neea cauld, Ah’s sure it’s a tissick ’at's gain about. Like iv’rything else, noo, they've gitten a foreign niam fler ’t—Russian influenza.
1943		(con. 1870s) G.A. Little Malachi Horan Remembers 78: Old Dr. Pentland, of Kells, who, seventy years ago, was in the habit of reciting [...] Whiskey cures the gout, / The colic and the tissic. / There’s not the slightest doubt, / It’s the very best of physic.
1953		Randolph & Wilson Down in the Holler 293: tissick: n. A cold, an infection of the throat or lungs.