Assessment of the Risk of Ebola Virus Transmission from Bodily Fluids and Fomites

1. J Infect Dis. (2007) 196 (Supplement 2): S142-S147. doi: 10.1086/520545

Abstract

Although Ebola virus (EBOV) is transmitted by unprotected physical contact with infected persons, few data exist on which specific bodily fluids are infected or on the risk of fomite transmission. Therefore, we tested various clinical specimens from 26 laboratory-confirmed cases of Ebola hemorrhagic fever, as well as environmental specimens collected from an isolation ward, for the presence of EBOV. Virus was detected by culture and/or reverse-transcription polymerase chain reaction in 16 of 54 clinical specimens (including saliva, stool, semen, breast milk, tears, nasal blood, and a skin swab) and in 2 of 33 environmental specimens.We conclude that EBOV is shed in a wide variety of bodily fluids during the acute period of illness but that the risk of transmission from fomites in an isolation ward and from convalescent patients is low when currently recommended infection control guidelines for the viral hemorrhagic fevers are followed.

Ebola virus (EBOV; family Filoviridae, genus Ebolavirus, type species Zaire ebolavirus) circulates in sub-Saharan Africa, where it occasionally causes large outbreaks of severe hemorrhagic fever with high case fatality rates [1]. The natural reservoir remains unknown, although bats are suspected [2]. Because no effective vaccine or specific antiviral therapy is available for Ebola hemorrhagic fever (EHF), the primary control strategy relies on aggressive contact tracing and isolation of patients with suspected cases in specialized isolation wards [3].

Large outbreaks of EHF are usually driven by personto-person transmission, with caregivers both at home and in hospitals being at particular risk [4]. Although direct contact with bodily fluids is considered to be the major risk factor [5–7], other than confirmation of EBOV in blood during acute illness, few data exist on which specific bodily fluids pose a risk and at what stages of infection. Furthermore, although extreme caution is recommended to prevent environmental contamination and exposure in isolation wards and detailed safety guidelines and protocols for decontamination have been developed [3], the role of fomites in the transmission of EBOV has not been explored. To better understand the precise modes of transmission, we sampled various clinical specimens from patients as well as from environmental surfaces in an isolation ward for EHF and analyzed them for the presence of EBOV.

http://jid.oxfordjournals.org/content/196/Supplement_2/S142.full

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