Try reinstalling pip and then reinstalling virtualenvwrapper (I had to go through these steps after upgrading to Mavericks):
$ sudo easy_install pip
$ sudo pip install --upgrade virtualenvwrapper
Try reinstalling pip and then reinstalling virtualenvwrapper (I had to go through these steps after upgrading to Mavericks):
$ sudo easy_install pip
$ sudo pip install --upgrade virtualenvwrapper