Unwanted contacts

A number of strange name formats recently appeared in my WLM contacts list. an example being live:laris_barbosa (whom I do not know). Others of the same format also appeared of friends, some of whose normal email addresses are in my contacts list.

I cannot delete the live: type contacts, which don't appear when I access contacts to send an email. Clicking on the live: entry just shows the name. In the example above: Larissa Fernanda Barbosa.

Why are these useless unwanted entries in my list, and how do I remove them?

Thanks