Outbreak of Human Monkeypox, Democratic Republic of Congo, 1996-1997
2001

Human Monkeypox Outbreak in the Democratic Republic of Congo

Sample size: 88 publication Evidence: moderate

Author Information

Author(s): Yvan J.F. Hutin, R. Joel Williams, Philippe Malfait, Richard Pebody, Vladamir N. Loparev, Susan L. Ropp, Mariangelli Rodriguez, Janice C Knight, Florimont K. Tshioko, Ali S Khan, Mark V. Szczeniowski, Joseph J. Esposito

Primary Institution: Centers for Disease Control and Prevention

Hypothesis

Is repeated animal reintroduction necessary to sustain monkeypox in the local human population?

Conclusion

The study suggests that repeated animal reintroduction of monkeypox virus is needed to sustain the disease in the local human population.

Supporting Evidence

  • 88 clinical cases were identified in 12 villages with an attack rate of 22 per 1,000.
  • 54% of retrospectively identified cases had antibodies against orthopoxvirus.
  • The case-fatality rate was 3.7% among the identified cases.
  • 73% of patients reported exposure to another case during the incubation period.
  • Seven active cases were confirmed by virus isolation.
  • Secondary attack rate within households was 8.3 per 100.
  • Antibodies were detected in 68% of patients by Western blotting.
  • Animal studies indicated that squirrels and Gambian rats may be reservoirs for the virus.

Takeaway

Monkeypox is a disease that can spread from animals to humans, and this study found that it needs animals to keep spreading among people.

Methodology

Epidemiologic and clinical studies were conducted in 12 villages, with case identification through dwelling-to-dwelling searches and serologic testing.

Potential Biases

Potential misclassification of cases and exposure sources due to reliance on retrospective data.

Limitations

Most cases were identified retrospectively without a case-control group, and the study was curtailed by civil unrest.

Participant Demographics

56.8% of case-patients were male, with a median age of 10 years.

Statistical Information

P-Value

0.02

Confidence Interval

95% CI 5.2% to 12.6%

Statistical Significance

p<0.05

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