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The American journal of tropical medicine and hygiene1993; 49(6); 677-685; doi: 10.4269/ajtmh.1993.49.677

Eastern equine encephalitis (EEE): a description of the 1989 outbreak, recent epidemiologic trends, and the association of rainfall with EEE occurrence.

Abstract: An Eastern equine encephalitis (EEE) outbreak in 1989 led to nine human and 196 equine cases, chiefly in coastal Atlantic and Gulf Coast counties. In the past two decades, EEE age-specific incidence and mortality rates have declined compared with earlier years. Analysis of rainfall patterns in areas where human EEE cases occurred between 1983 and 1989 revealed an association between occurrence of human cases and excess rainfall. The association was stronger with data from local weather stations than from statewide rainfall averages and the predictive models were best when applied to northern states. The sensitivity and specificity of these measures varied, depending on the model used, but the positive predictive value was no better than 50%, regardless of the rainfall model applied.
Publication Date: 1993-12-01 PubMed ID: 8279635DOI: 10.4269/ajtmh.1993.49.677Google Scholar: Lookup
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Summary

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This research paper discusses an outbreak of Eastern equine encephalitis in 1989, recent trends in the occurrence of the disease, and the potential link between rainfall and the occurrence of the disease. The study also explores the effectiveness of various predictive models in determining disease occurrence based on rainfall data.

Eastern equine encephalitis outbreak in 1989

The research began by discussing an outbreak of Eastern equine encephalitis, a mosquito-transmitted disease that affects both humans and horses. This outbreak, which occurred in 1989, resulted in nine human cases and 196 equine cases. It was predominantly concentrated in coastal Atlantic and Gulf Coast counties.

Epidemiologic trends in recent years

The study then delves into epidemiologic trends over the past two decades. Eastern equine encephalitis incidence and mortality rates have shown a decline compared with previous years. In other words, the study indicates that the number of new cases as well as the number of deaths due to EEE have decreased in more recent years.

Connection between rainfall and the occurrence of EEE

The researchers also analyzed rainfall patterns in areas where human EEE cases had been reported between 1983 and 1989. They identified a correlation between the occurrence of human cases and higher-than-average rainfall. This relationship seemed to be stronger when data was considered from local weather stations as opposed to statewide averages.

Effectiveness of predictive models

The authors evaluated various predictive models, all of which attempted to anticipate the occurrence of EEE based on rainfall data. The most accurate models were those tailored to northern states. However, the accuracy (or sensitivity) and specificity of these models varied. Regardless of model type, none provided a positive predictive value, a measure of how likely a positive result will correctly identify a case of the disease, of more than 50%. This means that the predictive models performed no better than chance at correctly predicting EEE occurrence based on rainfall data.

Cite This Article

APA
Letson GW, Bailey RE, Pearson J, Tsai TF. (1993). Eastern equine encephalitis (EEE): a description of the 1989 outbreak, recent epidemiologic trends, and the association of rainfall with EEE occurrence. Am J Trop Med Hyg, 49(6), 677-685. https://doi.org/10.4269/ajtmh.1993.49.677

Publication

ISSN: 0002-9637
NlmUniqueID: 0370507
Country: United States
Language: English
Volume: 49
Issue: 6
Pages: 677-685

Researcher Affiliations

Letson, G W
  • Division of Vector-Borne Infectious Diseases, Centers for Disease Control and Prevention, Fort Collins, Colorado.
Bailey, R E
    Pearson, J
      Tsai, T F

        MeSH Terms

        • Adolescent
        • Adult
        • Age Factors
        • Aged
        • Animals
        • Child
        • Disease Outbreaks / veterinary
        • Encephalomyelitis, Equine / complications
        • Encephalomyelitis, Equine / epidemiology
        • Encephalomyelitis, Equine / veterinary
        • Female
        • Horse Diseases / epidemiology
        • Horses
        • Humans
        • Incidence
        • Infant
        • Male
        • Mid-Atlantic Region / epidemiology
        • Middle Aged
        • Predictive Value of Tests
        • Rain
        • Southeastern United States / epidemiology

        Citations

        This article has been cited 14 times.
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