New species of Ebola virus discovered
Scientists have reported the discovery of a new species of Ebola virus, provisionally named Bundibugyo ebolavirus. This virus was responsible for a hemorrhagic fever outbreak in western Uganda in 2007. Ebola virus infection in humans causes severe disease for which there is presently no vaccine or other treatment. Case fatalities range historically between 53 and 90%. Therefore, research efforts into the Ebola virus genus and potential diagnostics are ongoing, with the discovery of Bundibugyo ebolavirus representing one of the latest pieces added to this puzzle. The new virus is genetically distinct from all other known Ebola virus species, differing by more than 30% at the genetic level. More traditional ELISA-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% 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.
Newly Discovered Ebola Virus Associated with Hemorrhagic Fever Outbreak in Uganda. 2008 PLoS Pathog 4(11): e1000212
Over the past 30 years, Zaire and Sudan ebolaviruses have been responsible for large hemorrhagic fever (HF) outbreaks with case fatalities ranging from 53% to 90%, while a third species, Cote d’Ivoire ebolavirus, caused a single non-fatal HF case. In November 2007, HF cases were reported in Bundibugyo District, Western Uganda. Laboratory investigation of the initial 29 suspect-case blood specimens by classic methods (antigen capture, IgM and IgG ELISA) and a recently developed random primed pyrosequencing approach quickly identified this to be an Ebola HF outbreak associated with a newly discovered ebolavirus species (Bundibugyo ebolavirus) distantly related to the Cote d’Ivoire ebolavirus found in western Africa. Due to the sequence divergence of this new virus relative to all previously recognized ebolaviruses, these findings have important implications for design of future diagnostic assays to monitor Ebola HF disease in humans and animals, and ongoing efforts to develop effective antivirals and vaccines.
Related:
- Congo confirms Ebola outbreak
- Marburg haemorrhagic fever in Uganda
- Deadly Marburg virus linked to fruit bat
Tags: Biology, Emerging disease, Health, Medicine, Microbiology, Science, Virology
Great. And my friends call me paranoid for being afraid of smallpox.
I think it’s time for the Special Pathogens Branch to screen other samples of other historically unexplained HF cases within the geographical region for Bundibugyo ebolavirus RNA’s. It’s extremely interesting that there is Ig cross-reactivity to other Ebola Virus strains that differ by up to 30%. I expect that the NS proteins of other Ebola virus strains (specifically Ivory Coast)will be able to trans complement cDNA clones of Bundibugyo ebolavirus with fatal mutations in the L gene and other NS genes. If this is truly the emergence of a new strain it would argue that the natural host (possibly a bat species) is under selective pressure leading to the development of a new strain. Determination of the selective pressure is vital to predicting new outbreaks.
You may like this…made using the Despair.com web site.
http://rybicki.wordpress.com/2008/11/25/despair/
Nice one Ed :-)