Papers by Alexandre Caron
We test the extent to which fence damage or fence permeability (resulting from human and elephant... more We test the extent to which fence damage or fence permeability (resulting from human and elephant damage) influences patterns of cattle and buffalo movement at the periphery of Gonarezhou National Park, Zimbabwe. We used spoor data to detect and compare the frequency of cattle and buffalo movement across the fence boundary. Results show that spoor proportions for cattle were significantly higher on fence partially damaged by humans than buffalo spoor. Conversely, buffalo spoor proportions were significantly higher on sections with totally removed fence as a result of elephant damage. Results suggest that cattle and buffalo use different sections of the damaged fence. R esum e Nous testons dans quelle mesure les d eg^ ats caus es aux cl^ otures ou la perm eabilit e de celles-ci (r esultant de l'action des hommes ou des el ephants) influencent les sch emas des d eplacements du b etail et des buffles a la p eriph erie du Parc National de Gonarezhou, au Zimbabwe. Nous avons utilis e les donn ees sur les traces pour d etecter et comparer la fr equence des passages du b etail et des buffles a travers la cl^ oture marquant la limite. Les r esultats montrent que la proportion de traces de b etail etait significativement plus grande a travers les cl^ otures partiellement endommag ees par les hommes que celles de buffles. Inversement, la proportion de traces de buffles etait significativement plus grande dans les sections o u la cl^ oture avait et e compl ete-ment enlev ee suite aux actions des el ephants. Les r esultats sugg erent que b etail et buffles traversent diff erentes sections de la cl^ oture endommag ee.
Annals of the New York Academy of Sciences, 2006
The widespread of immunodeficiency with AIDS, the consequence of poverty on sanitary protection a... more The widespread of immunodeficiency with AIDS, the consequence of poverty on sanitary protection and information at both individual and state levels lead control of tuberculosis (TB) to be one of the priorities of World Health Organization programs. The impact of bovine tuberculosis (BTB) on humans is poorly documented. However, BTB remains a major problem for livestock in developing countries particularly in Africa and wildlife is responsible for the failure of TB eradication programs. In Africa, the consumption of raw milk and raw meat, and the development of bushmeat consumption as a cheap source of proteins, represent one of the principal routes for human contaminations with BTB. The exploration of these different pathways using tools as participatory epidemiology allows the risk analysis of the impact of BTB on human health in Africa. This analysis represents a management support and decision tool in the study and the control of zoonotic BTB.
Revue d'Anthropologie de la Connaissance
Implementing surveillance in domestic animal populations has always encompassed more than the sim... more Implementing surveillance in domestic animal populations has always encompassed more than the simple fact of controlling the way they perform. Indeed, multiple aspects are at stake, evolving in relation to the social, political and economic context. In the case of South Rhodesia (to become Zimbabwe), complex animal surveillance and monitoring systems contributed to the territorial structuring and security of the colonial state as well as its economic development. With the independence of the country, these systems provided the basis for the control of foot and mouth disease according to international regulations, and provided an opportunity to develop a production system dedicated to exportation. These systems relied mainly on a partitioning and a “geographic confinement” of the living (colonists/indigenous people; human/animal; domestic/wild; healthy/unhealthy). The organization of these surveillance systems has been deeply shaken by the land reform of the 2000s’ and its re-establishmentis called into question by the upsurge in the political arena of concepts such as biodiversity and “One Health” associated to an ambition of a pro-poor economic development. New surveillance systems emerge (i.e. Transfrontier Conservation Areas, and sanitary standards such as the commodity-based trade) aiming at better associating the control of flows with the control of boundaries, and testifying of continuities and discontinuities with categories inherited from the colonial era.
Short Title: Rinderpest eradication in wildlife and livestock systems. A. Caron et R.A. Kock. Abs... more Short Title: Rinderpest eradication in wildlife and livestock systems. A. Caron et R.A. Kock. Abstract: The majority of surviving large mammal wildlife is within or dependent on protected areas and/or shares dry arid wilderness areas and their resources with livestock. Local communities, often pastoralists, see the wildlife as a competitor, source of disease or protein. The loss of much of the wild herbivore in West and Central African pastoral zones provides evidence for this. Health management in these mixed systems depends on the production objectives and disease risks play an important role in animal movement patterns. Mixed wildlife and livestock systems in certain situations (dry semi-arid lands) can produce more economic benefits to local communities than wildlife, livestock or dryland agriculture alone. One major question is what is the opportunity cost and disease risk inherent in this mixed system in relation to local communities' perceptions and how much can tourism and wildlife use compensates individuals. Rinderpest eradication in wildlife and livestock systems. A. Caron et R.A. Kock.
The ecology of host species is crucial for understanding the mechanisms of pathogen transmission ... more The ecology of host species is crucial for understanding the mechanisms of pathogen transmission and spread in complex multi-host systems. In this article, we use detailed observations of the host community to develop and apply a new approach to mapping temporal variation in risk for avian influenza. Working in an extensive wetland system near Harare, Zimbabwe, we use the overlap in space and time of highly variable bird communities, combined with ecological risk factors, to assess the risk of Avian Influenza viruses (AIV) maintenance and transmission between bird populations. The estimated introduction and maintenance risks associated with waterfowl populations at a given time are then multiplied by the level of interactions with neighboring domestic production systems during the same period. This approach is used to develop hypotheses for the dynamics of the introduction and circulation of AIV strains in waterfowl populations and as a way of understanding the potential role of "bridge" species at the wild/ domestic interface. The novel approach presented here offers a potentially useful way to explore AIV risk, identify which wild bird species may be acting as reservoirs or vectors of pathogens at a local scale, and improve local surveillance. Ecology and Society 15(3): 25 http://www.ecologyandsociety.org/vol15/iss3/art25/ developed and computationally challenging (Bascompte and Melian 2005, Rabbat et al. 2008).
Based on wildlife and domestic herbivore waterhole use count data collected in the South Eastern ... more Based on wildlife and domestic herbivore waterhole use count data collected in the South Eastern Lowveld of Zimbabwe between 2008 and 2011, we tested whether there was any significant overlap by wild and domestic herbivores in the use of waterholes located; 1) inside a wildlife protected area, 2) at the boundary of the protected and agricultural areas and 3) in the agricultural areas. We also explored whether species diversity at these three land uses vary significantly. Our results showed overlap in place and time between wild and domestic herbivores especially in the use of waterholes located at the boundary of the protected areas and at one waterhole located in the agricultural areas. Results also indicated that overall, 95% of wild herbivores prefered using waterholes located inside the protected area.Results of this study further demonstrated that animal species diversity declines significantly along a gradient from protected areas to agricultural areas. Overall, results of this study imply that the current emerging disease interface between wildlife and livestock may not necessarily be due to direct physical interaction between disease reservoir hosts or even sharing of same waterholes at the same time but rather an indirect contact. These findings could provide an important avenue of investigating livestock and wildlife disease outbreaks at the domestic -wildlife interface which are disturbing current efforts to improve livestock production as well as biodiversity conservation in African savannas.
Bird counts were carried out at thirty-four study sites within a perimeter of 10 km from the shor... more Bird counts were carried out at thirty-four study sites within a perimeter of 10 km from the shorelines of the two lakes, while all bird captures were conducted on a few sites along the shorelines of the two lakes. Both counting (22 missions) and capturing (15 missions) produced records of 297 bird species.
Newcastle disease (ND) is one of the most important and widespread avian pests. In Africa, backya... more Newcastle disease (ND) is one of the most important and widespread avian pests. In Africa, backyard poultry production systems are an important source of protein and cash for poor rural livelihoods. ND mortality in these production systems is important and seriously disrupts benefits derived from it. This study undertook an African continental approach of ND epidemiology in backyard poultry. After a systematic literature review of studies published from 1980 to 2009, a meta-analysis of spatio-temporal patterns of serological prevalence and outbreak occurrence was performed. Average ND serological prevalence was estimated at 0 . 67 [95 % confidence interval (CI) 0 . 58-0 . 75] in regions characterized by humid ecosystems, high human and poultry densities and low altitudes; 0 . 36 (95 % CI 0 . 30-0 . 41) in dry ecosystems at intermediate altitude where human and poultry densities are low and 0 . 27 (95 % CI 0 . 19-0 . 38) in mountain ecosystems where human and poultry densities are intermediate. In terms of seasonality, ND outbreaks occur mostly during the dry seasons in Africa, when environmental conditions are likely to be harshest for backyard poultry. In addition, a phylogeographical analysis revealed the regionalization of ND virus strains, their potential to evolve towards a higher pathogenicity from the local viral pool and suggests a risk for vaccine strains to provide new wild strains. These results present for the first time a continent-wide approach to ND epidemiology in Africa. More emphasis is needed for ND management and control in rural African poultry production systems.
Acta Tropica, 2014
The sharing of habitat by wild and domestic animals may result in pathogen transmission, notably ... more The sharing of habitat by wild and domestic animals may result in pathogen transmission, notably via ectoparasite vectors such as ticks. Interfaces between protected and communal lands constitute sharp transitions between areas occupied by host communities that are extremely contrasted in terms of composition, diversity and density. Empirical characterizations of tick communities and of their vertebrate hosts are strongly relevant for understanding the mechanisms leading to disease transmission between wild and domestic animals. In the present study we aimed at depicting the pattern of spatial variation in the density of immature ticks at such an interface located in Zimbabwe. At the end of the 2011 rainy season, we applied a hierarchical repeated protocol to collect ticks. We used the drag-sampling method in the vegetation surrounding water pans used by ungulates in 3 distinct landscape compartments (i.e. national park, mixed compartment and communal lands) characterized by a differential use by wild and domestic hosts. We combined generalized linear mixed models with site occupancy models to (1) assess tick aggregation levels at different spatial scales, (2) identify and disentangle factors which influence the density and probability of tick detection, and (3) compare robust estimations of tick densities among the landscape compartments. Ticks belonging to the Amblyomma and Riphicephalus genuses were found to be the most abundant. At small scale, ticks were more often detected in the afternoon and were more abundant close to water pans for Amblyomma and Riphicephalus genuses. Riphicephalus spp. density was also higher in grassland and bushland vegetation types as compared to woodland vegetation type. At large scale, for the three detected genuses, density was much higher near water pans located in the communal lands as compared to the national park and mixed compartment. Given that host community's diversity is much lower in the communal areas than in the two other landscape compartments, these results are compatible with a dilution effect but not sufficient to demonstrate this effect without additional studies. Up to date, it is the first utilization of these rigorous sampling and statistical modelling methodologies to estimate tick density in African ecosystem simultaneously at large and small scales.
Preventive Veterinary Medicine, 2014
Wild terrestrial birds can act as potential local spreaders or bridge hosts for avian influenza v... more Wild terrestrial birds can act as potential local spreaders or bridge hosts for avian influenza viruses (AIVs) between waterfowl (the maintenance hosts of AIVs) and domestic avian populations in which AIVs may cause disease. Few studies have investigated this hypothesis, although it is an important knowledge gap in our understanding of AIV spread within socioecosystems. We designed a simple and reproducible approach in an agro-ecosystem in Zimbabwe based on: (1) bird counts at key target sites (i.e., wetlands, villages, intensive poultry production buildings and ostrich farms) to identify which wild birds species cooccur in these different sites and seasons when the risk of AIV transmission through these potential bridge hosts is maximal and (2) targeted sampling and testing for AIV infection in the identified potential bridge hosts. We found that 12 wild bird species represented the vast majority (79%) of co-occurrences in the different sites, whereas 230 bird species were recorded in this ecosystem. Specifically, three species -barn swallow, Hirundo rustica, redbilled quelea, Quelea quelea and cattle egret, Bubulcus ibis -represented the main potential bridge host species (65% of co-occurrences). In two out of these three species (i.e., barn swallow and red-billed quelea), we detected AIV infections, confirming that they can play a bridge function between waterfowl and domestic species in the ecosystem. Our approach can be easily implemented in other ecosystems to identify potential bridge hosts, and our results have implications in terms of surveillance, risk management and control of AIV spread in socio-ecosystems.
Epidemiology and Infection, 2014
Newcastle disease (ND) is one of the most important and widespread avian pests. In Africa, backya... more Newcastle disease (ND) is one of the most important and widespread avian pests. In Africa, backyard poultry production systems are an important source of protein and cash for poor rural livelihoods. ND mortality in these production systems is important and seriously disrupts benefits derived from it. This study undertook an African continental approach of ND epidemiology in backyard poultry. After a systematic literature review of studies published from 1980 to 2009, a meta-analysis of spatio-temporal patterns of serological prevalence and outbreak occurrence was performed. Average ND serological prevalence was estimated at 0 . 67 [95 % confidence interval (CI) 0 . 58-0 . 75] in regions characterized by humid ecosystems, high human and poultry densities and low altitudes; 0 . 36 (95 % CI 0 . 30-0 . 41) in dry ecosystems at intermediate altitude where human and poultry densities are low and 0 . 27 (95 % CI 0 . 19-0 . 38) in mountain ecosystems where human and poultry densities are intermediate. In terms of seasonality, ND outbreaks occur mostly during the dry seasons in Africa, when environmental conditions are likely to be harshest for backyard poultry. In addition, a phylogeographical analysis revealed the regionalization of ND virus strains, their potential to evolve towards a higher pathogenicity from the local viral pool and suggests a risk for vaccine strains to provide new wild strains. These results present for the first time a continent-wide approach to ND epidemiology in Africa. More emphasis is needed for ND management and control in rural African poultry production systems.
New Frontiers of Molecular Epidemiology of Infectious Diseases, 2012
Emerging infectious diseases' hotspots have been identified as multi-host and multi-pathogen syst... more Emerging infectious diseases' hotspots have been identified as multi-host and multi-pathogen systems often characterized in tropical ecosystems by an extensive wildlife/domestic/human interface. The pathogen communities shared by the wild and domestic populations at this interface reflect the historical epidemiological interactions between them. In a research framework using recent community ecology, evolutionary biology and molecular biology advances, this information can be used to identify potential pathways for future pathogen spill-over initiating the emergence process. In other words, an understanding of the mechanisms of pathogen transmission in a specific ecosystem can provide an interaction network between host populations defined by nodes and edges and characterized by the frequency, intensity and direction of the interactions with a direct input for targeted disease surveillance.
Onderstepoort Journal of Veterinary Research, 2012
Brucellosis is an endemic disease in Zimbabwe caused by the genus Brucella. Brucella seroprevalen... more Brucellosis is an endemic disease in Zimbabwe caused by the genus Brucella. Brucella seroprevalence was recently reported to be high in the wildlife-livestock interface in the Chiredzi district and the neighbouring Gonarezhou National Park (GNP) in Zimbabwe, and higher amongst communal cattle with an abortion history and access to grazing in GNP than amongst communal cattle with no abortion history or access to grazing in GNP. The aim of this study was to investigate Brucella species in brucellosis seropositive cattle in the Chiredzi district with access to GNP using isolation and identification. Isolation of Brucella species from whole blood (n = 18) and milk samples (n = 10) from seropositive animals with an abortion history was based on the rose Bengal test (RBT) and enzyme-linked immunoassays (enzymelinked immunosorbent assay [ELISA]; indirect ELISA and complement ELISA), using microbiology and polymerase chain reaction (PCR) methods. Brucella abortus was cultured and identified from blood and milk collected from seropositive cows in both communal areas. The Brucella-specific 16-23S intergenic spacer (ITS) PCR and multiplex AMOS-PCR assays verified the identification of the cultures. Our results confirmed that B. abortus is present in cattle on communal farms in the Chiredzi district in Zimbabwe and might cause cattle abortions. The need for implementing control measures and raising public awareness on zoonotic transmission of brucellosis are recommended.
PLoS ONE, 2012
Heterogeneity in the transmission rates of pathogens across hosts or environments may produce dis... more 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.
BMC Evolutionary Biology, 2014
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Papers by Alexandre Caron