Risk for Ebola Virus Infection in Cote d'Ivoire.

To the Editor: In Tai National Park, Cote d'Ivoire, where a new strain of Ebola virus was isolated (1), the World Health Organization is conducting a project to identify the reservoir of the virus and evaluate the risk for its emergence in local populations. In March 1998, we conducted qualitative and quantitative surveys of the villagers' awareness of and risk for Ebola infection. In four villages close to Tai National Park (4 km to 10 km), we carried out structured interviews with 150 villagers and in-depth interviews with 17 villagers and three traditional healers.

Of the 150 villagers participating in the structured interviews, 18.0% had heard of Ebola (90.7% had heard of yellow fever). Of those aware of Ebola, 96.3% thought it life-threatening; 65.4% of them thought it preventable. When ill, 81.2% of the respondents generally relied on traditional healers or herbal medicine. During in-depth interviews traditional healers discussed their treatment practices. In one treatment, an incision is made on the skin and medicinal herbs are applied to the incision. Such traditional practices were implicated in the spread of Ebola virus in Gabon, where a traditional healer and his assistant (who were infected with Ebola virus) were suspected of spreading the virus to their patients through an unsterilized blade (1). The same practices would seem to pose a risk for virus transmission in Cote d'Ivoire.

Even though officially Tai National Park is protected from human activities to preserve its natural ecology, 84.0% of the 150 respondents to our survey often hunted or farmed in the park, 62.2% had encountered chimpanzees, and 53.3% had eaten chimpanzee meat. According to the in-depth interviews, chimpanzee meat is available at bush meat markets and is thought safe for eating, even though primates infected with Ebola virus have been linked with human cases (2,3).

Our survey results show that, even though no large-scale Ebola outbreaks have occurred in this area, villagers living near the park are at particularly high risk for infection because they are not aware of Ebola and do not know that their local customs and behavior may be putting them at risk. To prevent future Ebola epidemics in Africa, information, education, and communication (IEC) programs should be established (3). Moreover, further sociocultural studies on perceptions and behavior should be conducted in addition to exploring the nature of the virus and its cycle in the wild (2,4,5).

References

(1.) Georges A J, Leroy Em, Renault AA, et al. Ebola Hemorrhagic Fever Outbreaks in Bagon, 1994-1997. Epidemiologic and Health Control Issues. J Infect Dis 1999; 179 (Supp11):S65-75.

(2.) Le Guenno B, Formenty P, Wyers M, Gounon P, Walker F, Boesch C. Isolation and partial characterisation of a new strain of Ebola virus. Lancet 1995;345:1271-4.

(3.) Morris K. Facing up to tomorrow's epidemics. Lancet 1997;349:1301.

(4.) Georges-Courbot MC, Lu CY, Lansoud-Soukate J, Leroy E, Baize S. Isolation and partial molecular characterisation of a strain of Ebola virus during a recent epidemic of viral haemorrhagic fever in Gabon. Lancet 1997;349:181.

(5.) Tukei PM. Threat of Marburg and Ebola viral haemorrhagic fevers in Africa. East Afr Med J 1996;73:27-31.

Osamu Kunii,(*) Pierre Formenty,([dagger]) Jeanne Diarra-Nama([double dagger]) and Noel Nahounou([double dagger])

(*) International Medical Center of Japan, Tokyo, Japan; ([dagger]) WHO Tai Forest Project, Abidjan, Cote d'Ivoire; ([double dagger]) Ministre de la Sante Publique et des Affaires Sociales, Abidjan, Cote d'Ivoire