From the end of 1994 to the beginning of 1995, 49 patients with hemorrhagic symptoms were hospitalized in the Makokou General Hospital in northeastern Gabon. Yellow fever (YF) virus was first diagnosed in serum by use of polymerase chain reaction followed by blotting, and a vaccination campaign was immediately instituted. The epidemic, known as the fall 1994 epidemic, ended 6 weeks later. However, some aspects of this epidemic were atypical of YF infection, so a retrospective check for other etiologic agents was undertaken. Ebola (EBO) virus was found to be present concomitantly with YF virus in the epidemic. Two other epidemics (spring and fall 1996) occurred in the same province. GP and L genes of EBO virus isolates from all three epidemics were partially sequenced, which showed a difference of õ0.1% in the base pairs. Sequencing also showed that all isolates were very similar to subtype Zaire EBO virus isolates from the Democratic Republic of the Congo.

Of the 107 million COVID-19 cases worldwide, less than 2 million have been reported in African countries. The aim of this study was to evaluate the seroprevalence of SARS-CoV-2 infection in Ivory Coast mine workers.

BackgroundEight months after the detection of the first COVID-19 case in Africa, 1,262,476 cases have been reported in African countries compared to 72 million worldwide. The real burden of SARS-CoV-2 infection in West Africa is not clearly defined. The aim of the study was to evaluate the seroprevalence of SARS-CoV-2 in half of the 3,380 workers of several mining companies operating in two mines in the Ivory Coast and having its headquarters in the economic capital Abidjan.MethodsFrom 15th July to 13th October 2020, a voluntary serological test campaign was performed in the 3 sites where the companies operate: two mines, and the headquarters in Abidjan.We performed a COVID-PRESTO rapid test for the detection of IgG and IgM on capillary blood. A multivariate analysis was performed to identify independent sociodemographic characteristics associated with a higher SARS-CoV-2 seroprevalence rate.ResultsA total of 1,687 subjects were tested. 91% were male (n= 1,536) and mean age was 37 years old. The overall crude seroprevalence rate was 25.1% (n=422), but differing significantly between different sites, rising from 13.6% (11.2%-16.1%) in mine A to 34.4% (31.1%-37.7%) in mine B and 34.7% (26.2%-43.2%) in Abidjan. Non-resident workers in mines had a significantly lower prevalence rate than those living full-time in mines. Seroprevalence was 26.5% in natives of the Ivory Coast, while people coming from countries other than Africa were less likely to be SARS-CoV-2 seropositive. Among the 422 positive subjects, 74 reported mild symptoms in the three previous months and one was hospitalized for a severe COVID-19 infection.ConclusionThe prevalence of SARS-CoV-2 infection among mine workers in Ivory Coast is high. The low morbidity observed has probably led to an underestimation of the burden of this infection in West Africa. The high prevalence reported in subjects living in Abidjan, who have not any close contact with mine workers, may be indicative of the real seroprevalence in the Ivory Coast capital.

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