1. <i>Any</i> interracial sexual relationship. A black man who likes white women is also said to have "jungle fever". Some people associate the "jungle" with liking black people, but that is not the best use of the term. The Fever is generally seen as affecting both parties.
Mostly refers to interracial attraction because of stereotypes or curiosity. In Spike Lee's film (the origin of the term's popularity) both characters are referred to as suffering the 'disease' and are criticized by members of their race for the relationship.
See Stevie Wonder's Song:
<i>I've</i> Got jungle fever
She's got jungle fever
<i>We've</i> got jungle fever