By Maggie Fox, NBC News A virus that killed two teenagers in Congo in 2009 is a completely new type, related to rabies but causing the bleeding and rapid death that makes Ebola infection so terrifying, scientists reported on Thursday. They’re searching for the source of the virus, which may be transmitted by insects or bats. The new virus is being named Bas-Congo virus, for the area where it was found. Researchers are finding more and more of these new viruses, in part because new tests make it possible, but also in the hope of better understanding them so they can prevent pandemics of deadly disease. The virus infected a…