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Re-emergence of ebola haemorrhagic fever in Gabon

2002; Elsevier BV; Volume: 359; Issue: 9307 Linguagem: Inglês

10.1016/s0140-6736(02)07796-6

1474-547X

Eric M. Leroy, Sandrine Souquière, Pierre Rouquet, D Drevet,

Hepatitis B Virus Studies

On Nov 16, 2001, a woman arrived at the Mékambo Hospital from Medemba village, about 30 km south of Mékambo, Gabon. She was admitted with symptoms of high fever, asthenia, arthralgia, diarrhoea, and vomiting, and died 4 days later. Just before she died, evidence of blood was noted in her faeces and mouth. This woman was the fifth person in Medemba, all in the same family, to have such symptoms in less than 2 weeks. The other deceased family members had remained in the village. The first died on Oct 28. On Nov 26, a sixth member of the same family was admitted to Mékambo Hospital with the same symptoms. He died on Dec 1. On Nov 27, a nurse from the hospital, who had taken care of the woman, became ill and died in Makokou General Hospital on Dec 4, after developing similar symptoms. The symptoms and the within-family transmission of the disease suggested ebola haemorrhagic fever. Dead great apes (about 20 gorillas and four chimpanzees) have also been found by hunters near Medemba and neighbouring villages. On Dec 7, sera from the last two cases who died were sent to the Centre International de Recherches Médicales de Franceville (CIRMF) for testing by ebola antigen virus capture ELISA assay and IgG ELISA assay. Reverse transcriptase PCR to detect ebola viral RNA was also done on 200 μL of each serum sample.1Leroy EM Baize S Lu C-Y et al.Diagnosis of Ebola haemorrhagic fever by RT-PCR in an epidemic setting.J Med Virol. 2000; 60: 463-467Crossref PubMed Scopus (116) Google Scholar The two sera had high titres (>256) of virus antigen and contained ebola virus RNA. These results confirm ebola virus infection. No IgG to ebola viral antigens was detected, but this finding is consistent with previous results, showing that fatal cases of ebola infection do not develop specific IgG.2Baize S Leroy EM Georges-Courbot M-C et al.Defective humoral responses and extensive intravascular apoptosis are associated with fatal outcome in Ebola virus-infected patients.Nat Med. 1999; 5: 1-5Crossref PubMed Scopus (479) Google Scholar The outbreak of ebola haemorrhagic fever was officially declared on Dec 8, 2001. To characterise this new strain, we extracted viral RNA from the two sera. The first strands of cDNA from the L-gene were synthesised and amplified by a DNA thermal cycler 9700.1Leroy EM Baize S Lu C-Y et al.Diagnosis of Ebola haemorrhagic fever by RT-PCR in an epidemic setting.J Med Virol. 2000; 60: 463-467Crossref PubMed Scopus (116) Google Scholar Analysis of the sequenced PCR products (420 bp) showed only four synonymous substitutions compared with Mayinga-76 (DR Congo, 1976), Kikwit-95 (DR Congo, 1995), and Gabon-94 sequences. This strain is, therefore, new (Mekambo-01) and belongs to the Zaire subtype. The genetic diversity of this 420 bp sequence between Mekambo-01 and Gabon-94 strains is 0·95%. Molecular characterisation of the glycoprotein and the nucleoprotein genes is in progress at CIRMF. On Dec 20, 2001, the outbreak was still continuing, and national (Gabonese public health authorities and army medical services, and CIRMF) and international (WHO, Médecins Sans Frontières, and Institut Pasteur-Mérieux de Lyon) teams are trying to contain it. This is the fourth outbreak of ebola in Gabon in 6 years, the last one ending in May, 19973Georges AJ Leroy EM Renaut AA et al.Ebola hemorrhagic fever outbreaks in Gabon, 1994–1997: epidemiologic and health control issues.J Infect Dis. 1999; 179: S65-S75Crossref PubMed Scopus (242) Google Scholar, and for the fourth time, the outbreak happened in the same area of Gabon (Ogooué-Ivindo province). The virus, therefore, circulates at a high concentration in this area. The reservoir for the ebola virus is still unknown and this situation reinforces the need to search for it in this densely contaminated area.