3,000 Thai teenagers suffer from sexually transmitted diseases annually, a three-fold increase in five years, and gonorrhea and venereal ulcers are the most common infections, the health ministry reported on Thursday.Dr Manit Theeratantikanont, director-general of the Disease Control Department, said STDs were spreading among Thai teenagers at an appalling rate.The incidence of infection had risen three-fold in the past five years, from 1,000 patients to 3,000 a year.The most common diseases were gonorrhea and chancroids, followed by venereal warts and HIV/Aids.More young men suffer from such diseases than females, he said.The concern is that more youngsters in the 14-15 age group are getting STDs, he said.Young people are starting to have sex as young as...