That's 1 person left for every 10,000.

I live in an urban centre with approximately 6 million people within a 100km radius (Toronto).

That means that only 600 people will be left in a region approximately 15,000 square kilometres in size - simplifying by assuming that Lake Ontario to the south means the bottom half of the 100 km radius circle is water, but good enough for this analysis.

That's 25 square kilometres per person.

I'm going to assume also that the virus killed everyone in such a way that local grocery stores, etc are exhausted - meaning the virus didn't infect everyone (long incubation time) and then suddenly kill everyone in hours or something. Also, there's no grid power but gasoline and cars are still fairly abundant, enough for the few survivors to scavenge.

Hospitals and civic centres are probably clogged with millions of dead as the health care system becomes overwhelmed. Sports stadiums would be filled with dead too, as the government tries to do everything it can to treat people.

Because of this, Toronto proper - where the highest densities of people are - would be unlivable. The survivors would be densest here, so they'd more easily be able to band together - and in general, I think that's what would happen - the survivors would work together or they'd die pretty quickly. And because, Canada, and not The Walking

These survivors in the densest population centres would need to leave the dense areas as soon as possible. 99.99% kill rates would overwhelm the ability of the government to dispose of bodies. The population dense areas would soon be full of rotting bodies and disease.

The first thing that people will consider is the need for water. That will lead them to one of the three major North south watersheds that cut across the Toronto area, and then probably south to the lake. These will be natural places to congregate, with more wide open spaces but lots of potential for shelter due to the natural surroundings.

If it's the dead of winter these 3 groups would most likely stay isolated and wait it out - there's 30+ kilometres between each group so it's unlikely they'd be able to remotely contacted other.

Once the ice thaws, someone will be smart enough to realize there will be other survivors who congregate around the watersheds. That would lead to exploration and contact via canoe or boat, etc. Hopefully all the survivors would band together in one or two major camps to reach critical mass to maintain a viable community.

By this point organized groups of survivors would be able to better scavenge the city for technology and what consumables are available. Small scale farming would start in the watershed valleys.

Scavenged technology will inevitably include ham radios and that will allow the local survivors to reach out to the more distant remains of humanity.