“What do you give a dog with a fever?”/“Mustard—it’s the best thing for a hot dog!”

A “hot” dog riddle is:
 
Q: What do you give a dog with a fever? 
A: Mustard. It’s the best thing for a hot dog!
 
The joke has been cited in print since at least 1978.
 
       
25 February 1978, Battle Creek (MI) Enquirer and News, “Mini Jokes,” The Mini Page, pg. 3, col. 1:
Nurse: I think my dog has a fever.
Doctor: You better get me some mustard.
Nurse: Why?
Doctor: Because I always put mustard on a hot dog.
—Serene Swift, Battle Creek
     
Google Books
1981, Boys’ Life, “Think & Grin,” pg. ?:
Moe: I think my dog has a fever.
Joe: Go get the mustard.
Moe: Mustard? Why?
Joe: Because it’s the best thing for a hot dog.—Kevin Earl, Delta, Colo.
 
Google Books
Lu & Clancy’s Secret Codes
By Adrienne Mason and Pat Cupples
Toronto, ON: Kids Can Press
1999
Pg. 40:
Joke: What should you give a dog with a fever?
Mustard. It’s the best thing for a hot dog.
   
Google Books
Over 1500 Fantastic Jokes
By Guy Campbell and Paul Moran
London, UK: Dean
2002
Pg. 76:
What do you give a dog with a fever?
Mustard, it’s the best thing for a hot dog!
   
Google Groups: alt.humor.puns
Weakly Jest For Kids 03-02-04
Stan Kegel
3/2/04
(...)
What do you give a dog with a fever? 
Mustard. It’s the best thing for a hot dog!  (Jane, 8)
 
Twitter
Oly Grocery Outlet
@OlympiaGO
Bad Joke of the Day:  What do you give a dog wth a fever?  Mustard - it’s the best thing for a hot dog!
9:05 AM - 24 Aug 2009
 
Google Books
Funny Animal Jokes For Kids
By Peter Crumpton
PeteyRF Creative
2015
Pg. ?:
What do you give a dog with a fever?
Mustard, it’s the best thing for a hot dog!
 
Google Books
Happy Smile:
Jokes for Kids
By Adam Smith
Lulu Press (Lulu.com)
2017
Pg. ?:
Q: What do you give a dog with a fever?
A: Mustard, it’s the best thing for a hot dog!