Which of the following statements about Yaws is not TRUE?

Yaws is a non veneral disease and has three modes of transmission: Direct contact - with the secretions from the infectious lesions Fomites - indirectly through the fomites and also eahen floor Vector - through flies and insects that feed on the lesions Sexual transmission, trans-placental and congenital transmission has not been established. Ref: Park Textbook of Preventive and Social Medicine, 19th Edition, Pages 283-284; Textbook of Microbiology By Ananthanarayan and Panicker, 7th Edition, Page 385