Physics · Dynamics
VirginSoilEpidemic
A disease reaching a population with no prior exposure kills a larger share of it, adults included, than where the disease is endemic
Definition
Mechanism
Where a disease is endemic, most adults have survived it and carry acquired immunity, so it strikes mainly the young. When it first reaches a population that has never been exposed, members of all ages fall ill at once, so the care, food-getting and defence that the healthy provide fail as well, and deaths from neglect and hunger add to those from the disease. Several new diseases arriving within a generation compound the losses, and violence, hunger or displacement at the same time raise mortality further and slow recovery. A disease new to every population, and excess deaths explained by inherited susceptibility rather than by the absence of prior exposure, are not instances.
Invariants
- The population has had no prior exposure to the disease, so its adults carry no acquired immunity to it.
- The share of the population the disease kills exceeds that in populations where it is endemic.
- Members of all ages fall ill in the same outbreak.
Risks
Failure modes
Germs absolve
a population's collapse is credited to disease alone, hiding the war, enslavement, hunger and displacement that raised mortality and prevented recovery.
Innate weakness assumed
excess deaths are attributed to inherited susceptibility rather than to the absence of prior exposure and to social disruption.
One disease blamed
losses from several successive diseases are credited to one.
Relationships
Root pattern: builds on nothing in this library.
Nothing in this library builds on this pattern yet.