The most common and most likely answer to this crossword clue is the 4 letter word YAWS
I've seen this crossword clue in The Daily Telegraph
Y
A
W
S
Buddy explains!
The straight part
We know that "Disease" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case disease = yaws.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does YAWS mean?
YAWS noun- A contagious tropical disease, caused by the spirochete Treponema pertenue, characterized by yellowish or reddish tumors, which often resemble currants, strawberries, or raspberries.
- The rotation of an aircraft, ship, or missile about its vertical axis so as to cause the longitudinal axis of the aircraft, ship, or missile to deviate from the flight line or heading in its horizontal plane.
- The angle between the longitudinal axis of a projectile at any moment and the tangent to the trajectory in the corresponding point of flight of the projectile.
- A vessel's motion rotating about the vertical axis, so the bow yaws from side to side; a characteristic of unsteadiness.
- The extent of yawing, the rotation angle about the vertical axis
- To turn about the vertical axis while maintaining course.
- To swerve off course to port or starboard.
- To steer badly, zigzagging back and forth across the intended course of a boat; to go out of the line of course.
- To rise in blisters, breaking in white froth, as cane juice in the clarifiers in sugar works.
- A single tumor in the disease called yaws.