The social networking site Facebook is being used by authorities in Wales to try and contact 650 people who attended a dance camp after two girls fell ill as a result of contracting the bacterium E.coli. Because E.coli can be acquired from a wide range of sources, environmental health officials are keen to establish the source of the outbreak and investigate whether there have been other cases. In addition to more traditional methods such as letters, e-mails and the phone, a spokeswoman said officials had turned to Facebook because the dance camp had its own group on the website. Neither of the girls is believed to be in a critical condition.