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close this bookEpidemiologic Surveillance after Natural Disaster (PAHO - OPS; 1982; 105 pages) [FR] [ES]
close this folderPart 1 : Epidemiologic surveillance and disease control after natural disaster
close this folderChapter 2 : Postdisaster potential of communicable disease epidemics
View the documentExposure of susceptibles to endemic communicable disease
View the documentIncreases in levels of endemic communicable disease in local populations
View the documentSpecial problems with communicable disease in encamped populations
View the documentCommunicable diseases after disasters

Increases in levels of endemic communicable disease in local populations

It must be appreciated that reports of communicable diseases should be expected to increase during medical relief periods in communities with high levels of contagious diseases. If medical services were not in existence before a disaster, instituting them afterwards will certainly increase the apparent levels of disease. Even when primary health services do exist before disaster, regular disease reporting is usually very incomplete. After a disaster, reports increase because the number of reporting units is augmented. The total population served may also be swollen by movement into the area. Clinicians used to practicing under other local conditions may be confronted with clinical syndromes with which they are unfamiliar, and try to make etiologic diagnoses without diagnostic laboratory support.

During an epidemic—defined as an unexpected number of cases of a communicable disease—it is extremely important to determine whether increases in disease are real or are only apparent. Except in encamped refugees, the precise figure of the total population at risk is rarely available for the calculation of reported case rates, which is the number of reported cases divided by total population at risk. Thus, it may be necessary to perform a rapid survey in the community to reach an approximation of how common a communicable disease is in the general population. Trends can be monitored by examining retrospective and prospective clinic reports of patients seen with the condition. However, even when evaluation is performed, it may be difficult to decide whether an increase in rates is significant enough to warrant taking emergency control measures or requesting additional medical supplies or staff.

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