I was thinking about the health warnings being given at the time about the “Black Syph” (so named because your genitals turned that color before rotting off). There were also rumors circulated about service men with incurable STD infections being confined to permanent residence clinics in the Philippines essentially to die.
Considering the source regions for this STD, maybe the warnings and the rumors had some truth in them.
I spent some time looking for info on VD island. Could never find any proof of it. There are many legends around the war and I suspect this was a creation of NCO’s trying to scare the men into not having sex with hookers. If there was Black syph there would be scholarly papers on the disease. Of course if every man that contracted it died well then, dead men tell no tales.
http://www2.iath.virginia.edu/sixties/HTML_docs/Texts/Scholarly/Baky_White_Cong_01.html