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Last year, an outbreak of what appeared to be a new form of the hemorrhagic fever Ebola surfaced in western Uganda. I blogged about this apparent new strain frequently.

Now, in the journal PLoS pathogens, the existence of a new form of Ebola is confirmed. Its name: Bundibugyo ebolavirus. From the proMED email:

The new virus is genetically distinct from all other known Ebola virus species, differing by more than 30 percent at the genetic level. More traditional ELISA (enzyme-linked immunosorbent assay)-based assays detected the new virus; however, the unique nature of this virus created initial challenges for traditional Ebola virus molecular diagnostic assays and genome sequencing approaches.

To determine the genetic signature of this new Ebola virus species, scientists used a recently developed random-primed pyrosequencing approach, quickly determining the genetic sequence of over 70 percent of the virus genome.

Knowledge of this sequence then allowed for the rapid development of a sensitive molecular detection assay, which was deployed to the field as part of the outbreak response. This draft sequence also allowed for easy completion of the whole genome sequence using a traditional primer walking approach and prompt confirmation that this virus represented a new Ebola virus species. Current worldwide efforts to design effective diagnostics, antivirals, and vaccines will need to take into account the distinct nature of this new member of the Ebola virus genus.

So we officially have a new strain of Ebola, some 30% different from previous strains.  I do not know if 30% is par for the course or way different, but it does mean that the Ebola virus continues to evolve while maintaining its ability to kill over 50% of the people it infects.