A nice roundup of the current ebolavirus outbreak in Western Africa in New Scientist.
Debora MacKenzie also raises an interesting question about whether an ebolavirus outbreak in an urban environment would give the virus a chance to mutate and become more contagious. Whilst an increased number of susceptible people would provide the virus with the ‘resources’ to mutate (i.e. more infections > more mutations > evolutionary selection for advantageous mutations), the comparison with avian influenza is a stretch. Avian Flu is a strain of a readily contagious, airbourne virus. Ebola transmission occurs through contact with infected body fluids; close physical contact is a requirement.
HIV, which is also mentioned in the article, provides a nice counter-point: it also spreads through contact with infected body fluids, but is of course now endemic in a number of countries. The difference to Ebola? Initial HIV symptoms are far more insidious and Flu-like. People spread the virus because they don’t know they have it. Ebola is a different story altogether. Haemorrhagic fevers are overtly scary diseases that hit around a week after infection. The ability for health enforcement to intervene in such an outbreak is very high because you can readily find out who is infected and separate them from susceptible, uninfected people.
So yes, the virus could evolve to more contagious in an urban environment, but the inefficient route of transmission the virus relies upon means that this would likely be a very slow process.