A Singapore Medical Journal article, written by 10 local doctors in 1969, said Koro is "a disease characterised by the sudden delusion of penis retracting, accompanied by intense panic".
Koro first gained public attention on Oct 29, 1967, after a newspaper report that some people developed Koro from eating pork from pigs inoculated with anti-swine-fever vaccine.
Rumours spread that eating such pork would cause the disease - and death. At the height of the outbreak, 97 men with Koro went to the emergency unit of the Singapore General Hospital in one day. The article said the spike in the number of cases, the rapidity of "spread" and the concentration of cases pointed to an "epidemic" in the real sense. In November 1967, public announcements were made by the Singapore Medical Association and the Health Ministry, stating that Koro was a result of fear and not a physical disease with fatalities.