Highly pathogenic avian influenza virus A/H5N1 was first officially reported in Africa in early 2006. Since the first outbreak in Nigeria, this virus spread rapidly to other African countries. From its emergence to early 2008, 11 African countries experienced A/H5N1 outbreaks in poultry and human cases were also reported in three of these countries. At present, little is known of the epidemiology and molecular evolution of A/H5N1 viruses in Africa. We have generated 494 full gene sequences from 67 African isolates and applied molecular analysis tools to a total of 1,152 A/H5N1 sequences obtained from viruses isolated in Africa, Europe and the Middle East between 2006 and early 2008. Detailed phylogenetic analyses of the 8 gene viral segments confirmed that 3 distinct sublineages were introduced, which have persisted and spread across the continent over this 2-year period. Additionally, our molecular epidemiological studies highlighted the association between genetic clustering and area of origin in a majority of cases. Molecular signatures unique to strains isolated in selected areas also gave us a clearer picture of the spread of A/H5N1 viruses across the continent. Mutations described as typical of human influenza viruses in the genes coding for internal proteins or associated with host adaptation and increased resistance to antiviral drugs have also been detected in the genes coding for transmembrane proteins. These findings raise concern for the possible human health risk presented by viruses with these genetic properties and highlight the need for increased efforts to monitor the evolution of A/H5N1 viruses across the African continent. They further stress how imperative it is to implement sustainable control strategies to improve animal and public health at a global level.

A recombinant capripoxvirus vaccine containing a cDNA of the peste-des-petits-ruminants virus (PPRV) fusion protein gene was constructed. A quick and efficient method was used to select a highly purified recombinant virus clone. A trial showed that a dose of this recombinant as low as 0

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Dans le cadre de la campagne panafricaine de lutte contre la peste bovine, une enquête sérologique portant sur 5720 sérums a été menée dans la province de l'Adamaoua au Cameroun. La couverture immunitaire générale varie de 60 à 73 % dans les quatre départements visités. Il est conseillé de vacciner les animaux dès l'âge de 6 mois, de renouveler le matériel de vaccination, de remettre en état les parcs de contention et d'utiliser le sulfate de magnésium ou, à la rigueur, le sérum physiologique pour la reconstitution du vaccin lyophilisé.

Le Laboratoire national vétérinaire (LANAVET) de Garoua (Cameroun) exécute le volet séro-surveillance dans le cadre de la Campagne panafricaine de lutte contre la peste bovine (PARC) depuis 1989. En 1993, l'enquête a porté sur 8 517 sérums prélevés dans 286 troupeaux bovins âgés de 0 à 3 ans. La prévalence observée a été de 54 %. Deux mille dix sérums issus de 68 troupeaux à faible taux d'anticorps bovipestiques ont été testés par la technique ELISA de compétition, adaptée à la peste des petits ruminants (PPR). Seuls, 91 des sérums (4,5 %) ont présenté des anticorps anti-virus de la PPR, ce qui n'augmente pas de manière significative le niveau de protection du cheptel vis-à-vis de la peste bovine. D'autre part, la faiblesse de l'immunité post-vaccinale contre la peste bovine n'est vraisemblablement pas due à l'infection des bovins par le virus de la PPR.