That sounds reminiscent to what happened during the Black Death.
Unfortunately, it doesn't sound like it worked particularly well, considering the Plague still took a sizeable percentage of the human population at the time.
Villages that quarantined themselves during the Plague were left completely to their own devices. Back then, you couldn't even try to communicate with other villages without risking the messenger's life.
Today, outsiders can airlift food, clean water, and medical supplies to any isolated village that asks for help. So let's stop wasting resources on people who don't want to be helped, and focus on people who actually are desperate for help.
You do realize _how_ isolated these villages are right? Like the only stranger they see in a month is an itinerant trader? How exactly are they supposed to safely get word out to the "civilized" world? That is assuming that they have already heard that there is a disease going around and what the proper precautions are...
Mechanism and agents of infection weren't understood at the time of the Black Death. We know what causes Ebola, and how it is transmitted. We know how to selectively allow what we need for survival (water, food, other commodities) to transit between infected and noninfected zones.
No, not every individual knows or understands this, particularly in primitive areas. But the global system as a whole does.
As for the Black Death, there are instances of specific villages or households (or castle-holds) who sealed themselves off and had sufficient stores to see themselves through the plague.
Today, outsiders can airlift food, clean water, and medical supplies to any isolated village that asks for help. So let's stop wasting resources on people who don't want to be helped, and focus on people who actually are desperate for help.