Environmental health in emergencies

Disease outbreaks of unknown etiology

Laboratory technician

Occasionally, an outbreak or cluster of disease is seen in a population for which the cause is unclear. These outbreaks may be due to a new or modified pathogen, a natural toxin, an initially undetected release of a chemical, or over-exposure to ionizing radiation from an unknown source. Careful history taking and epidemiological study may point to one or more possible causes that can then provide a focus for further, more specialized investigation.

Nodding disease, observed in Southern Sudan, is an example of a disease for which the etiological agent remains a mystery.

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