x1 is infected/contaminated by something which was infected/contaminated by something which was infected/contaminated by ... which was infected/contaminated by x2, regarding/pertaining to contagion x3 and via means of transmission x4, through intermediary nodes x5 (ce'o list).
This word is a brapagjvo of "selprejumydu'a" and ".utka"; each sumti slot should be interpreted as in those words - for example, "contagion" is used broadly, as in the definition of "prejumydu'a". If we temporarily constrain x3 to a biological disease, then in one sense of the word, x2 (an upstream, although perhaps not ultimate, source) is an epidemiological/'viral' vector of contagion x3; in another sense of the word, x5 (the transmission pathway) is so. See also: "prejumydu'a'y'utka". Technically, because "prejumydu'a" is not a binary predicate, it maybe should be avoided as a modifier of ".utka".