An Outbreak of Spotted Fever Rickettsiosis in U.S. Army Troops Deployed to Botswana
1996

Outbreak of Spotted Fever Rickettsiosis in U.S. Army Troops in Botswana

Sample size: 169 publication Evidence: moderate

Author Information

Author(s): Bonnie L. Smoak, M.D., Ph.D., J. Bruce McClain, M.D., John F. Brundage, M.D., Laurel Broadhurst, M.D., Daryl J. Kelly, Ph.D., Gregory A. Dasch, Ph.D., Richard N. Miller, M.D.

Primary Institution: Walter Reed Army Institute of Research

Hypothesis

What is the impact of a brief training exercise in Botswana on the health of U.S. soldiers regarding rickettsial disease?

Conclusion

The study documented a significant outbreak of spotted fever rickettsiosis among U.S. soldiers during a training exercise in Botswana.

Supporting Evidence

  • Approximately 30% of soldiers sought medical attention after returning from Botswana.
  • The overall attack rate was 23% among the deployed soldiers.
  • 67% of seroconverted case-patients were symptomatic.
  • Case-patients reported classic symptoms of rickettsial diseases.
  • An incubation period of up to 6 days was estimated.
  • Case-patients were more likely to report tick bites than non-case-patients.
  • Most soldiers did not use insect repellent during the exercise.
  • All case-patients responded rapidly to antibiotic treatment.

Takeaway

When soldiers went to Botswana for training, many got sick from a bug bite that caused a fever and other symptoms.

Methodology

The study involved a questionnaire, physical examinations, and serological testing of soldiers who participated in a training exercise.

Potential Biases

Potential bias in self-reported symptoms and exposure to vectors.

Limitations

The study did not isolate rickettsiae from ticks or human specimens, and the sample size for some analyses was small.

Participant Demographics

Most soldiers were non-Hispanic white, with a median age of 23.5 years.

Statistical Information

P-Value

p < 0.0001

Confidence Interval

95% C.I.: 77, 239

Statistical Significance

p < 0.0001

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