Is there any evidence that a virus can modify human evolution
The simplest example, that I can recall are the flu pandemics. The 1918 pandemic is the first to be described because of its severity, but quite possibly not the first in human history (see for example the Black Death - Yersinia pestis is a bacterium, but in the 15th century in just a few years it covered almost all of Europe, sometimes killing up to 40% of population in a given area).

Influenza pandemics appeared quite regularly during the 20th century, usually every 20 years and killed suspiciously many people compared to yearly influenza strains. Additionally, a person who survived one pandemic, was unaffected or only mildly affected by the next pandemic. 

All this suggests, that the pandemics "clear" the population from susceptible individuals, and regularity of pandemics (notice, that 20 years is more or less the time of one human generation!) assures that the new generations also go through this kind of selection. The surviving individuals are more resistant to all strains of influenza then those, who never suffered from a pandemic. Maybe the influenza didn't mutate our DNA, but it could be a major force of natural selection.

And one more note: did you notice the great noise in media every time a new potentially pandemic strain is discovered? Actually, it's not just hyperboly of the danger. Last pandemic was in the '70s, so it's high time for a new one. And, since the last one was  almost 40 years ago, the new one (when it happens) will probably be very severe.