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Background Avian influenza viruses (AIV) have been detected in wild birds in West Africa during the northern winter, but no information is available on a potential year-round circulation of AIV in West Africa. Such year-round circulation would allow reassortment opportunities between strains circulating in Afrotropical birds and strains imported by migratory birds wintering in West Africa. Objective and Method A 2-year longitudinal survey was conducted in the largest continental wetland of West Africa, the Inner Niger Delta in Mali, to determine the year-round circulation of AIV in wild birds. Results and Conclusions Avian influenza virus RNA was detected during all periods of the year. Very low prevalence was detected during the absence of the migratory wild birds. However, a year-round circulation of AIV seems possible in West Africa, as shown in other African regions. West Africa may hence be another potential site of reassortment between AIV strains originating from both Afro-tropical and Eurasian regions. (Resume d'auteur)

The inland delta of the Niger, a vast floodplain, is the only refuge of Black Crowned Cranes in Mali. This study, centred on the regions of Mopti, Tenenkou and Youwarou, aimed to: (1) census the number of cranes in the delta and in captivity in the towns of Mopti and Bamako; (2) examine exploitation at different levels (local and national) to estimate the number of birds captured and traded, and the sums of money involved; and (3) to set up a plan for the conservation of the species. From April to August 2001 a survey was conducted amongst the hunters, buyers, sellers and those holding cranes in the towns of Mopti and Bamako. In these towns 55 people, most of whom had kept and raised cranes for more than 15 years, had 129 Black Crowned Cranes in captivity. Dealing in cranes is an activity restricted to men (farmers, aviculturalists, fishermen and traders). Over the period 1998–2000, 165 birds were bought and sold, while 70 had been exported to other countries. The average purchase price from a hunter was €24. In the delta the selling price was on average 36 278FCFA (francs of the African Financial Community) (€55), whereas in the towns the price was 104 778FCFA (€159) over the same time period. All trophies from the hunt were also sold. Clearly, the survival of this species is threatened both by habitat destruction and by hunting. Under captive conditions the birds do not breed and continued captures could lead to the extinction of cranes in Mali. A plan for the protection of the species has been drawn up and financial support is now being sought. Le Delta Intérieur du Niger (DIN), vaste plaine d'inondation est le seul sanctuaire des Grues couronnées au Mali. C'est dans cette zone de refuge, que l'étude sur «le statut de la Grue couronnée et surexploitation au Mali» a été menée, principalement dans les cercles de Mopti, Tenenkou et Youwarou. Le District de Bamako (capitale du Mali), considérée comme la plaque tournante de toutes les transactions commerciales (achat, vente, et exportation) a été aussi enquêtée. L'étude avait les objectifs suivants: Inventorier les effectifs de Grue couronnée dans le DIN et en captivité dans les villes de Mopti et Bamako en vue de déterminer son statut de protection;Etudier la filière d'exploitation à différentes échelles (local et national) en vue d'une estimation des effectifs capturés, achetés et vendus et des revenus monétaires obtenus;Proposer un plan d'action et sa mise en oeuvre en faveur de la Grue couronnée. Pendant la période d'Avril–Août 2001, une enquête a été menée dans les cercles ci-dessus cités auprès des chasseurs, acheteurs et vendeurs. La même enquête a été menée dans les villes de Mopti et Bamako auprès des éleveurs à domicile et des commerçants. Dans les villes de Mopti et Bamako, 55 éleveurs détiennent en captivité 129 Grues couronnées et se sont les hommes qui élèvent ses oiseaux dans leur basse-cour. La plupart d'entre eux ont plus d'une quinzaine d'années dans cet élevage. La commercialisation de la Grue couronnée est une activité pratiquée seulement par les hommes (agriculteurs, éleveurs, pêcheurs, commerçants). 165 individus vivants ont faits de transactions commerciales (achat/vente) pendant la période 1998-2000 et 70 individus ont été enregistrés à l'exploitation vers les pays Africains, Arabes et Européens. Le prix moyen à l'achat est €24/individu entre les mains des chasseurs. Les prix moyens à la vente sont respectivement de 36278FCFA (€55)/individu, sur le DIN (période 1998–2000), Mopti, Tenenkou et Youwarou contre 104 778FCFA (€159) en villes, communes II, III et IV, pour la même période. Toutes les trophées de l'oiseau sont aussi vendues. Il est apparu les contraintes suivantes à la survie de cette espèce: la disparition et la dégradation de son habitat et la chasse. Dans les conditions actuelles de captivité l'oiseau ne se reproduit pas et la conséquence pourrait être son extinction au Mali. Wetlands International, la DRCN/Mopti et d'autres ONGs ont élaborés un plan d'action en faveur de la protection de l'espèce dont la mise en oeuvre est présentement l'objet de recherche des financements. Ostrich 2007, 78(2): 195–203

International audience; Heterogeneity in the transmission rates of pathogens across hosts or environments may produce disease hotspots, which are defined as specific sites, times or species associations in which the infection rate is consistently elevated. Hotspots for avian influenza virus (AIV) in wild birds are largely unstudied and poorly understood. A striking feature is the existence of a unique but consistent AIV hotspot in shorebirds (Charadriiformes) associated with a single species at a specific location and time (ruddy turnstone Arenaria interpres at Delaware Bay, USA, in May). This unique case, though a valuable reference, limits our capacity to explore and understand the general properties of AIV hotspots in shorebirds. Unfortunately, relatively few shorebirds have been sampled outside Delaware Bay and they belong to only a few shorebird families; there also has been a lack of consistent oropharyngeal sampling as a complement to cloacal sampling. In this study we looked for AIV hotspots associated with other shorebird species and/or with some of the larger congregation sites of shorebirds in the old world. We assembled and analysed a regionally extensive dataset of AIV prevalence from 69 shorebird species sampled in 25 countries across Africa and Western Eurasia. Despite this diverse and extensive coverage we did not detect any new shorebird AIV hotspots. Neither large shorebird congregation sites nor the ruddy turnstone were consistently associated with AIV hotspots. We did, however, find a low but widespread circulation of AIV in shorebirds that contrast with the absence of AIV previously reported in shorebirds in Europe. A very high AIV antibody prevalence coupled to a low infection rate was found in both first-year and adult birds of two migratory sandpiper species, suggesting the potential existence of an AIV hotspot along their migratory flyway that is yet to be discovered.

Please cite this paper as: Cappelle et al. (2012) Circulation of avian influenza viruses in wild birds in Inner Niger Delta, Mali. Influenza and Other Respiratory Viruses 6(4), 240–244. Background Avian influenza viruses (AIV) have been detected in wild birds in West Africa during the northern winter, but no information is available on a potential year‐round circulation of AIV in West Africa. Such year‐round circulation would allow reassortment opportunities between strains circulating in Afro‐tropical birds and strains imported by migratory birds wintering in West Africa. Objective and Method A 2‐year longitudinal survey was conducted in the largest continental wetland of West Africa, the Inner Niger Delta in Mali, to determine the year‐round circulation of AIV in wild birds. Results and Conclusions Avian influenza virus RNA was detected during all periods of the year. Very low prevalence was detected during the absence of the migratory wild birds. However, a year‐round circulation of AIV seems possible in West Africa, as shown in other African regions. West Africa may hence be another potential site of reassortment between AIV strains originating from both Afro‐tropical and Eurasian regions.

Despite considerable effort for surveillance of wild birds for avian influenza viruses (AIVs), empirical investigations of ecological drivers of AIV prevalence in wild birds are still scarce. Here we used a continental-scale dataset, collected in tropical wetlands of 15 African countries, to test the relative roles of a range of ecological factors on patterns of AIV prevalence in wildfowl. Seasonal and geographical variations in prevalence were positively related to the local density of the wildfowl community and to the wintering period of Eurasian migratory birds in Africa. The predominant influence of wildfowl density with no influence of climatic conditions suggests, in contrast to temperate regions, a predominant role for inter-individual transmission rather than transmission via long-lived virus persisting in the environment. Higher prevalences were found in Anas species than in non- Anas species even when we account for differences in their foraging behaviour (primarily dabbling or not) or their geographical origin (Eurasian or Afro-tropical), suggesting the existence of intrinsic differences between wildfowl taxonomic groups in receptivity to infection. Birds were found infected as often in oropharyngeal as in cloacal samples, but rarely for both types of sample concurrently, indicating that both respiratory and digestive tracts may be important for AIV replication.

Predicting areas of disease emergence when no epidemiological data is available is essential for the implementation of efficient surveillance programs. The Inner Niger Delta (IND) in Mali is a major African wetland where >1 million Palearctic and African waterbirds congregate. Waterbirds are the main reservoir of Avian Influenza Viruses (AIV). Our objective was to model their spatial distribution in order to predict where these viruses would be more likely to circulate. We developed a generalized linear model (GLM) and a boosted regression trees (BRT) model based on total aerial bird counts taken in winter over 6 years. We used remotely sensed environmental variables with a high temporal resolution (10 days) to predict the spatial distribution of four waterbird groups. The predicted waterbird abundances were weighted with an epidemiological indicator based on the prevalence of low pathogenic AIV reported in the literature. The BRT model had the best predictive power and allowed prediction of the high variability of waterbird distribution. Years with low flood levels showed areas with a higher risk of circulation and had better spatial distribution predictions. Each year, the model identified a few areas with a higher risk of AIV circulation. This model can be applied every 10 days to evaluate the risk of AIV emergence in wild waterbirds. By taking into account the IND's ecological variability, it allows better targeting of areas considered for surveillance. This could enhance the control of emerging diseases at a local and regional scale, especially when resources available for surveillance programs are scarce.

Background: Characterizing the interface between wild and domestic animal populations is increasingly recognized as essential in the context of emerging infectious diseases (EIDs) that are transmitted by wildlife. More specifically, the spatial and temporal distribution of contact rates between wild and domestic hosts is a key parameter for modeling EIDs transmission dynamics. We integrated satellite telemetry, remote sensing and ground-based surveys to evaluate the spatio-temporal dynamics of indirect contacts between wild and domestic birds to estimate the risk that avian pathogens such as avian influenza and Newcastle viruses will be transmitted between wildlife to poultry. We monitored comb ducks (Sarkidiornis melanotos melanotos) with satellite transmitters for seven months in an extensive Afro-tropical wetland (the Inner Niger Delta) in Mali and characterise the spatial distribution of backyard poultry in villages. We modelled the spatial distribution of wild ducks using 250-meter spatial resolution and 8-days temporal resolution remotely-sensed environmental indicators based on a Maxent niche modelling method.Results: Our results show a strong seasonal variation in potential contact rate between wild ducks and poultry. We found that the exposure of poultry to wild birds was greatest at the end of the dry season and the beginning of the rainy season, when comb ducks disperse from natural water bodies to irrigated areas near villages.Conclusions: Our study provides at a local scale a quantitative evidence of the seasonal variability of contact rate between wild and domestic bird populations. It illustrates a GIS-based methodology for estimating epidemiological contact rates at the wildlife and livestock interface integrating high-resolution satellite telemetry and remote sensing data. © 2011 Cappelle et al; licensee BioMed Central Ltd., SCOPUS: ar.j, info:eu-repo/semantics/published