Types of Disasters and Their Consequences

American Public Health Association 

In This Article


The spread of infectious disease depends upon pre-existing levels of the disease, ecological changes resulting from disaster, population displacement, changes in density of population, disruption of public utilities, interruption of basic public health services, and compromises to sanitation and hygiene. The risk that epidemics of infectious disease will occur is proportional to the population density and displacement. A true epidemic can occur in susceptible populations in the presence or impending introduction of a disease agent compounded by the presence of a mechanism that facilitates large-scale transmission (e.g., contaminated water supply or vector population).

Quick response is essential because epidemics, which result in human and economic losses and political difficulties, often arise rapidly. An epidemic or threatened epidemic can become an emergency when the following characteristics of the events are present. Not all of these characteristics need be present and must be assessed with regard to relative importance locally:

  • risk of introduction to and spread of the disease in the population;

  • large number of cases may reasonably be expected to occur;

  • disease involved is of such severity as to lead to serious disability or death;

  • risk of social or economic disruption resulting from the presence of the disease;

  • authorities are unable to cope adequately with the situation due to insufficient technical or professional personnel, organizational experience, and necessary supplies or equipment (e.g., drugs, vaccines, laboratory diagnostic materials, vector-control materials);

  • risk of international transmission.

The categorization of "emergency" differs from country to country, depending on two local factors: whether the disease is endemic and a means of transmitting the agent exists. Table 7 describes epidemic emergencies for particular diseases listed in endemic and nonendemic areas.

Click here to view Table 8 .

  • Control or to prevent epidemic situations.

  • Conduct surveillance to identify when an epidemic is likely to occur.

  • Ensure that items requiring refrigeration, such as vaccines, are kept refrigerated throughout the chain of distribution.

  • Monitor the maintenance of immunization programs against childhood infectious disease (e.g., measles, mumps, polio).


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