Haemorrhagic fever virus activity in equatorial Africa: distribution and prevalence of filovirus reactive antibody in the Central African Republic

Abstract

Seroepidemiological surveys were conducted to determine the frequency and distribution of haemorrhagic fever virus (HFV) activity in the Central African Republic. Human serum specimens (4295) were collected from 5 ecologically distinct zones. Serological evidence of HFV activity was found in all the zones. The filovirus antibody prevalence (24.4%, 1051/4295) was greater than the combined prevalence for Lassa virus, Rift Valley fever virus and Crimean-Congo HFV antibody (1.1%, 45/4295; P < 0.01). Evidence of filovirus activity was found in all zones: 21.3% (914/4295) of the population were seropositive for Ebola virus antibody while only 3.2% (137/4295) were seroreactive with Marburg viral antigens. Age and sex were important host-related factors influencing filovirus activity, particularly in dry grassland and moist forest communities. These communities shared many factors, but differences, such as agricultural practices and ethnic backgrounds, may also affect the risk of infection. Filovirus infections appear to occur without apparent disease. Continued investigations are needed to evaluate the true pathogenicity of the African filoviruses and the likelihood that unidentified serologically cross-reacting and non-pathogenic members of the filovirus family are active in equatorial Africa.

Leptospirosis and Ebola virus infection in five gold-panning villages in northeastern Gabon.

“…7 Previous findings have also shown a relationship between serologic status and ethnic group. 9,26 In our survey, serologic status was independent of sex, age, and ethnic group. The epidemic context, with its high incidence of disease, has been able to even out differences observed elsewhere in the absence of any clinical symptoms.…”

“…12 The seroprevalence of the Ebola virus in the gold-panning villages along the Nouna River is similar to previous findings reported elsewhere in tropical forest areas of Central Africa without periods of acute epidemics. 9,10,26 However, under similar epidemiologic conditions, Gonzales and others in 1989 reported an Ebola virus fever seroprevalence two times higher in the capital of the same province, 150 km from the Nouna area. 7 In this last survey, an indirect immunofluorescent assay was used with reference strains from Zaïre and Sudan, which may be less specific than the ELISA used in this study.…”

“…The Ebola virus is endemic to central Africa, [6][7][8][9][10][11] occurring in isolated epidemics throughout the region, [12][13][14] specifically on three occasions between 1994 and 1996 in Gabon. 15,16 Several strains of the virus have been characterized, some of which may cause a clinically atypical disease in an as yet unknown proportion of cases.…”

How severe and prevalent are Ebola and Marburg viruses? A systematic review and meta-analysis of the case fatality rates and seroprevalence

“…After full evaluation of retrieved publications, 72 articles were included in this study. Of those included in the study, 23 reported outbreaks of EVD (Table 1) [3, 8, 27–41, 7, 42, 43], 12 reported outbreaks of MVD (Table 2) [10, 11, 42, 44–51], 26 reported sero-prevalence of Ebola virus (Table 3) [8, 12–14, 28, 31, 52–54, 29, 55–70] and 11 reported sero-prevalence of Marburg virus (Table 4) [14, 15, 57, 61–64, 67, 71–73]. Most of the sero-prevalence studies reported both Marburg and Ebola viruses.…”

Policy Debate | International Responses to Global Epidemics: Ebola and Beyond

“…102 The papers published in The Lancet originally purporting the presence of Ebola in humans in Zaire (Bowen et al, 1977;Johnson et al, 1977;Pattyn et al, 1977) and later in the Central African Republic (Johnson et al, 1993) have attracted criticism regarding the handling of specimens, insufficiency of sample sizes, and poor quality of the electromicroscopy.…”