In their desperation to control the spread of the virus, some governments opted to use nuclear weaponry on heavily infected areas of their own countries. Nuclear countries also received requests from their non-nuclear neighbors to target areas within their countries as well. All their efforts were futile. The virus and the infected continued to spread.
On the North American continent Canada's military and main government was overrun quicker than anyone would have believed possible. In desperation, the citizens who were unable to be evacuated requested the nuclear bombing of Toronto, Montreal, Portland, Halifax, Saint John, and Kingston from their American neighbors. With great regret, America answered their pleas and nuked the cities. Despite the sacrifice, it did little to nothing to help them.
In it's own country, America tactically nuked Philadelphi and Harrisburg PA, Houston TX, Phoenix AZ, Seattle WA, Atlanta GA, Jacksonville and Orlando Fla, San Francisco and San Diego CA were all nuked.
In Mexico the US military nuked Mexico City, Tijuana, Chichuahua, and Zapopan, at the request of the Mexican government. As with Canada, it was a futile attempt.
Despite the devastation caused by the nukes, the infection continued to spread. Around the world, countless people died by fire and radiation, and still the number of infected grew.
Now, where people once found cities, they often find radioactive wastelands. Places better skirted around, rather than passed through. If they must be passed through, it's best to do it quickly, and have a radiation detector to help avoid the most heavily contaminated areas.
Between the radiation levels in some areas, acid rain clouds, and the infected, some wonder how anyone has managed to survive so far, or if humankind will ultimately fall to this new hostile world he must now call home.