Newcastle Disease Virus in Madagascar: Identification of an Original Genotype Possibly Deriving from a Died Out Ancestor of Genotype IV

In Madagascar, Newcastle disease (ND) has become enzootic after the first documented epizootics in 1946, with recurrent annual outbreaks causing mortality up to 40%. Four ND viruses recently isolated in Madagascar were genotypically and pathotypically characterised. By phylogenetic inference based on the F and HN genes, and also full-genome sequence analyses, the NDV Malagasy isolates form a cluster distant enough to constitute a new genotype hereby proposed as genotype XI. This new genotype is presumably deriving from an ancestor close to genotype IV introduced in the island probably more than 50 years ago. Our data show also that all the previously described neutralising epitopes are conserved between Malagasy and vaccine strains. However, the potential implication in vaccination failures of specific amino acid substitutions predominantly found on surface-exposed epitopes of F and HN proteins is discussed

Landscape attributes driving avian influenza virus circulation in the Lake Alaotra region of Madagascar

While the spatial pattern of the highly pathogenic avian influenza H5N1 virus has been studied throughout Southeast Asia, little is known on the spatial risk factors for avian influenza in Africa. In the present paper, we combined serological data from poultry and remotely sensed environmental factors in the Lake Alaotra region of Madagascar to explore for any association between avian influenza and landscape variables. Serological data from cross-sectional surveys carried out on poultry in 2008 and 2009 were examined together with a Landsat 7 satellite image analysed using supervised classification. The dominant landscape features in a 1-km buffer around farmhouses and distance to the closest water body were extracted. A total of 1,038 individual bird blood samples emanating from 241 flocks were analysed, and the association between avian influenza seroprevalence and these landcape variables was quantified using logistic regression models. No evidence of the presence of H5 or H7 avian influenza subtypes was found, suggesting that only low pathogenic avian influenza (LPAI) circulated. Three predominant land cover classes were identified around the poultry farms: grassland savannah, rice paddy fields and wetlands. A significant negative relationship was found between LPAI seroprevalence and distance to the closest body of water. We also found that LPAI seroprevalence was higher in farms characterised by predominant wetlands or rice landscapes than in those surrounded by dry savannah. Results from this study suggest that if highly pathogenic avian influenza H5N1 virus were introduced in Madagascar, the environmental conditions that prevail in Lake Alaotra region may allow the virus to spread and persis

Le réseau régional AnimalRisk : de la surveillance à la recherche dans l'Océan Indien

National audienceThe Animal Risk regional network: surveillance and research in the Indian Ocean. To meet the challenges of emerging diseases in the Indian Ocean region, in 2009 animal health stakeholders set up the Animal Risk-OI network, designed to provide technicaland scientific support to surveillance systems and to suggest ways of improving health risk control in the area. The network is supported by OIE referring bodies for the Indian Ocean—veterinary services and animal health research organizations. Animal Risk-OI is not intended to replace current monitoring systems but to help consider arising issues through bimonthly webconferences, annual meetings and quarterly newsletters, and to provide information for research aiming to clarify theepidemiology of certain diseases and recommend suitable control measures. This paper presents the preliminary findings following the monitoring and investigation of diseases considered by network partners to be of top priority. Apart from pursuing synergy between surveillance and research activities, the network aims to bridge the gap between animal and human health to instigate ajoint, standardized approach to the assessment and control of health risks in the Indian Ocean region.Pour répondre aux défis lancés par les maladies émergentes dans l’Océan Indien, les acteurs de la santé animale ont mis en place depuis début 2009 le réseau AnimalRisk-OI. Ce réseau a pour objectif d’apporter un soutien technique et scientifique aux systèmes de surveillance et de proposer des réponses pour une meilleure gestion des risques sanitaires dans la zone. Les partenaires sont les référents de l’OIE dans l’Océan Indien, à savoir les services vétérinaires ainsi que les structures de recherché impliquées en santé animale. Le réseau AnimalRisk-OI n’a pas pour vocation de se substituer aux systèmes de surveillance existants, mais il est chargé d’animer une réflexion autour des problématiques observées par des téléweb conférences bimensuelles, des réunions annuelles et des bulletins d’information trimestriels et de nourrir des actions de recherche qui visent à mieux comprendre l’épidémiologie de certaines maladies et donc de proposer des mesures de gestion adéquates pour mieux les maîtriser. Les premiers résultats de la surveillance et des investigations sur certaines maladies considérées prioritaires par les partenaires sont présentés ici. Les orientations envisagées, outre la poursuite de la synergie entre les actions de surveillance et de recherche, sont un rapprochement avec la santé humaine pour permettre une approche commune et harmonisée de l’appréciation et de la gestion des risques sanitaires dans l’Océan Indien