Sentence:  Conditions were horrendous aboard most British naval vessels at the time. Scurvy and other <WSD>diseases</WSD> ran rampant, killing more seamen each year than all other causes combined, including combat. 
Meaning of the word marked with <WSD> tags:  An abnormal condition of a human, animal or plant that causes discomfort or dysfunction; distinct from injury insofar as the latter is usually instantaneously acquired.