mal cativo

Etymology
Attested since the 18th century. From, "[the] little sickness"

Noun

 * 1)  an unidentified sickness (18th-19th centuries)
 * 2)  a nervous sickness, thought to be caused by evil eye or other malediction
 * 3)  ataxia
 * 4)  syphilis
 * 1)  syphilis

Usage notes
It is always preceded by the definite article (or any of its alternative forms) so as to differentiate it from, "a little sickness".