The 7-year-old son of migrant workers was diagnosed with venereal disease after allegedly being sexually assaulted by his teacher in a primary school in Hubei province, local media reported.

The boy, from Shadun village in the province, was diagnosed with condyloma acuminatum, genital warts. The diagnosis also confirmed the presence of the papillomavirus in his body.

The boy's mother, surnamed Peng who used to work in Hangzhou, Zhejiang province, first called a Hangzhou radio station to seek help, saying that the boy had been sexually assaulted by a teacher in the school toilet.

The child was at home with grandparents while the parents worked in Hangzhou and then Guangzhou.

The mother only found out recently when the family were on holiday together.

Her son said that the teacher bought snacks for the boy after class every day and asked him to wait in the toilet, according to the mother.

Police have launched an investigation.