Emerging Infectious Diseases (Nov 2003)

Ebola Hemorrhagic Fever Transmission and Risk Factors of Contacts, Uganda

  • Paolo Francesconi,
  • Zabulon Yoti,
  • Silvia Declich,
  • Paul Awil Onek,
  • Massimo Fabiani,
  • Joseph Olango,
  • Roberta Andraghetti,
  • Pierre E. Rollin,
  • Cyprian Opira,
  • Donato Greco,
  • Stefania Salmaso

DOI
https://doi.org/10.3201/eid0911.030339
Journal volume & issue
Vol. 9, no. 11
pp. 1430 – 1437

Abstract

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From August 2000 through January 2001, a large epidemic of Ebola hemorrhagic fever occurred in Uganda, with 425 cases and 224 deaths. Starting from three laboratory-confirmed cases, we traced the chains of transmission for three generations, until we reached the primary case-patients (i.e., persons with an unidentified source of infection). We then prospectively identified the other contacts in whom the disease had developed. To identify the risk factors associated with transmission, we interviewed both healthy and ill contacts (or their proxies) who had been reported by the case-patients (or their proxies) and who met the criteria set for contact tracing during surveillance. The patterns of exposure of 24 case-patients and 65 healthy contacts were defined, and crude and adjusted prevalence proportion ratios (PPR) were estimated for different types of exposure. Contact with the patient’s body fluids (PPR = 4.61%, 95% confidence interval 1.73 to 12.29) was the strongest risk factor, although transmission through fomites also seems possible.

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