Human Ebola Outbreak Resulting from Direct Exposure to Fruit Bats in Luebo, Democratic Republic of Congo, 2007

Abstract

Twelve years after the Kikwit Ebola outbreak in 1995, Ebola virus reemerged in the Occidental Kasaï province of the Democratic Republic of Congo (DRC) between May and November 2007, affecting more than 260 humans and causing 186 deaths. During this latter outbreak we conducted several epidemiological investigations to identify the underlying ecological conditions and animal sources. Qualitative social and environmental data were collected through interviews with villagers and by direct observation. The local populations reported no unusual morbidity or mortality among wild or domestic animals, but they described a massive annual fruit bat migration toward the southeast, up the Lulua River. Migrating bats settled in the outbreak area for several weeks, between April and May, nestling in the numerous fruit trees in Ndongo and Koumelele islands as well as in palm trees of a largely abandoned plantation. They were massively hunted by villagers, for whom they represented a major source of protein. By tracing back the initial human-human transmission events, we were able to show that, in May, the putative first human victim bought freshly killed bats from hunters to eat. We were able to reconstruct the likely initial human-human transmission events that preceded the outbreak. This study provides the most likely sequence of events linking a human Ebola outbreak to exposure to fruit bats, a putative virus reservoir. These findings support the suspected role of bats in the natural cycle of Ebola virus and indicate that the massive seasonal fruit bat migrations should be taken into account in operational Ebola risk maps and seasonal alerts in the DRC.

Modeling of Wildlife-Associated Zoonoses: Applications and Caveats

“…complex, and both the behavior of individuals and multiple coupling points of transmission between species influence pathogen dynamics. Pathogen transmission to the human host appears to result from direct contact with infected wildlife species through the handling and eating of bush meat (duiker, primates, and bats; Leroy et al 2009), a culturallylimiting behavior, or ingestion of fruit contaminated with Ebola-infected bat saliva (Leroy et al 2009). Although the host spectrum and reservoir of infection have not been determined conclusively, three bat species are considered putative virus reservoirs (Leroy et al 2005).…”

Molecular Evolution of Viruses of the Family Filoviridae Based on 97 Whole-Genome Sequences

“…During person-to-person transmission, there appears to be little molecular evolution of the virus (3,16). Initial introduction into the human population is often thought to result from contact with infected carcasses of nonhuman primates or other mammals or direct contact with an infected reservoir host (17)(18)(19)(20)(21). Despite numerous attempts to identify the natural reservoir(s) of the filoviruses over the past Ն30 years, only recently have bats been implicated as possible reservoirs for the ebolaviruses and marburgviruses (20)(21)(22)(23)(24).…”

Lignes directrices pour de meilleures pratiques en matière de suivi de la santé et de contrôle des maladies des populations de grands singes

“…La voie d'infection des grands singes n'est pas confirmée mais on suspecte le contact direct ou indirect avec une espèce réservoir, sans doute des chauve-souris frugivores, et/ou le contact avec une carcasse animale infectée (Leroy et al 2004(Leroy et al , 2009) ou le contact direct avec d'autres grands singes infectés (Caillaud et al 2006). Au sudouest de l'Ouganda, il est avéré que des chauve-souris frugivores se trouvant à quelques kilomètres de l'habitat des gorilles sont un réservoir du virus de Marburg, un virus très proche (Towner et al 2009 (Formenty et al 1999).…”