In such a scenario you'd basically have to treat it like a zombie apocalypse. Shelter within the safety of armed groups or hidden bunkers stocked full of food. If the bunker is hidden and supplied well enough to last a year, one might be able to ride out the die off and evade the cannibals just long enough to poke their heads out when the supplies are low to see what is what. The remaining 10% of the population will either be road warrior mad maxesque villains or folks that were well prepared. Beware of those who have shaky hands, especially if they offer you food as kuru may be a sign that you do not want to accept any hospitality from that particular stranger.