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Periodicity in the Annual Incidence of Reported Cases of Yellow Fever during the past Fifty Years
Summary
- 1. An analysis has been made of the periodicity of severe epidemics of yellow fever in Africa and South America during the past 50 years.
- 2. Successive peaks of unusual prevalence of reported cases of that disease have recurred after intervals of from two to 13 years. No consistent pattern has been discernable although the most frequent interval was six years.
- 3. The periodicity of large numbers of fatalities, as revealed by the viscerotome service, has likewise been irregular and has shown a median value of six and a half years.