The effectiveness of animal health surveillance systems depends on their capacity to gather sanit... more The effectiveness of animal health surveillance systems depends on their capacity to gather sanitary information from the animal production sector. In order to assess this capacity we analyzed the flow of sanitary information regarding Highly Pathogenic Avian Influenza (HPAI) suspicions in poultry in Vietnam. Participatory methods were applied to assess the type of actors and likelihood of information sharing between actors in case of HPAI suspicion in poultry. While the reporting of HPAI suspicions is mandatory, private actors had more access to information than public actors. Actors of the upstream sector (medicine and feed sellers) played a key role in the diffusion of information. The central role of these actors and the influence of the information flow on the adoption by poultry production stakeholders of behaviors limiting (e.g. prevention measures) or promoting disease transmission (e.g. increased animal movements) should be accounted for in the design of surveillance and co...
ABSTRACT Summary1. Inference about demographic parameters of animal and plant natural populations... more ABSTRACT Summary1. Inference about demographic parameters of animal and plant natural populations is important to evaluate the consequences of global changes on populations. Investigating the factors driving their variation over space and time allows evaluating the relative importance of biotic and abiotic variables in shaping the dynamics of a population. Although numerous studies have identified the factors possibly affecting population dynamics, they have barely formally determined the routes by which these different factors are related to demographic parameters.2. We focus on mark–recapture (MR) models that provide unbiased estimators of demographic parameters, while explicitly coping with imperfect detection inherent to wild populations. MR models allow estimating the effect of covariates on demographic parameters and testing their significance in a regression-like framework. However, these models can only detect correlations and do not inform on causal pathways (e.g. direct vs. indirect effects) in the relationships between demographic parameters and the factors possibly explaining their variability.3. We develop an integrated model to perform path analysis (PA) of MR data, to examine causal relationships among several (including demographic) variables. This approach is implemented in a Bayesian framework using Markov chain Monte Carlo.4. To motivate our developments, we analyse 17 years of mark–recapture data from Atlantic puffins (Fratercula arctica), to investigate the mechanisms through which environmental conditions have an impact on puffins’ adult survival. Using our PA-based MR modelling approach, we found that local climatic conditions had an indirect and lagged impact on puffin survival through their influence on local abundance of herring. Besides, we found no evidence for any lagged effect through an alternative unknown pathway (e.g. abundance of another resource).5. Our method allows elucidating pathways through which environmental, trophic or density-dependent factors influence demographic parameters, while accounting for detectability <1. This is a critical step to understand the interactions of a species with its environment and to predict the impacts of global change on its viability.
A cross-sectional study was conducted to estimate the seroprevalence of lumpy skin disease (LSD) ... more A cross-sectional study was conducted to estimate the seroprevalence of lumpy skin disease (LSD) in the different agro-climatic zones prevailing in Ethiopia. A total of 2368 serum samples were collected from 42 kebeles located in 15 districts and tested using indirect fluorescent antibody test (IFAT) and virus neutralization test (VNT). The herd and animal true LSD serological prevalence were estimated in each agro-climate zone using a Bayesian model. The intra-cluster correlation coefficient (ICC) was evaluated using a random-effect model. According to the serological prevalence estimations, LSD affected differently the three agro-climatic zones considered. Herd level seroprevalence was higher in the midland agro-climate zone 64% (95% CI: 53-74) as compared to the highland 26% (95% CI: 17-36) and the lowland 50% (95% CI: 40-60) agro-climates. Animal level seroprevalence in infected herds was also higher in the midland agro-climate zone 31% (95% CI: 24-40) than in the highland and lowland zones (24% (95% CI: 18-31) and 23% (95% CI: 18-29), respectively). Higher ICC value in the highland agro-climate zone implies that increased sample sizes should be particularly required for this zone in future studies to estimate LSD prevalence or incidence with a desired precision level. This seroprevalence study also suggests that the prevalence of LSD infection in Ethiopia is higher than what has been previously reported. In the light of these updated estimations, we discuss options to trigger appropriate control measures in the future.
The effectiveness of animal health surveillance systems depends on their capacity to gather sanit... more The effectiveness of animal health surveillance systems depends on their capacity to gather sanitary information from the animal production sector. In order to assess this capacity we analyzed the flow of sanitary information regarding Highly Pathogenic Avian Influenza (HPAI) suspicions in poultry in Vietnam. Participatory methods were applied to assess the type of actors and likelihood of information sharing between actors in case of HPAI suspicion in poultry. While the reporting of HPAI suspicions is mandatory, private actors had more access to information than public actors. Actors of the upstream sector (medicine and feed sellers) played a key role in the diffusion of information. The central role of these actors and the influence of the information flow on the adoption by poultry production stakeholders of behaviors limiting (e.g. prevention measures) or promoting disease transmission (e.g. increased animal movements) should be accounted for in the design of surveillance and co...
ABSTRACT Summary1. Inference about demographic parameters of animal and plant natural populations... more ABSTRACT Summary1. Inference about demographic parameters of animal and plant natural populations is important to evaluate the consequences of global changes on populations. Investigating the factors driving their variation over space and time allows evaluating the relative importance of biotic and abiotic variables in shaping the dynamics of a population. Although numerous studies have identified the factors possibly affecting population dynamics, they have barely formally determined the routes by which these different factors are related to demographic parameters.2. We focus on mark–recapture (MR) models that provide unbiased estimators of demographic parameters, while explicitly coping with imperfect detection inherent to wild populations. MR models allow estimating the effect of covariates on demographic parameters and testing their significance in a regression-like framework. However, these models can only detect correlations and do not inform on causal pathways (e.g. direct vs. indirect effects) in the relationships between demographic parameters and the factors possibly explaining their variability.3. We develop an integrated model to perform path analysis (PA) of MR data, to examine causal relationships among several (including demographic) variables. This approach is implemented in a Bayesian framework using Markov chain Monte Carlo.4. To motivate our developments, we analyse 17 years of mark–recapture data from Atlantic puffins (Fratercula arctica), to investigate the mechanisms through which environmental conditions have an impact on puffins’ adult survival. Using our PA-based MR modelling approach, we found that local climatic conditions had an indirect and lagged impact on puffin survival through their influence on local abundance of herring. Besides, we found no evidence for any lagged effect through an alternative unknown pathway (e.g. abundance of another resource).5. Our method allows elucidating pathways through which environmental, trophic or density-dependent factors influence demographic parameters, while accounting for detectability <1. This is a critical step to understand the interactions of a species with its environment and to predict the impacts of global change on its viability.
A cross-sectional study was conducted to estimate the seroprevalence of lumpy skin disease (LSD) ... more A cross-sectional study was conducted to estimate the seroprevalence of lumpy skin disease (LSD) in the different agro-climatic zones prevailing in Ethiopia. A total of 2368 serum samples were collected from 42 kebeles located in 15 districts and tested using indirect fluorescent antibody test (IFAT) and virus neutralization test (VNT). The herd and animal true LSD serological prevalence were estimated in each agro-climate zone using a Bayesian model. The intra-cluster correlation coefficient (ICC) was evaluated using a random-effect model. According to the serological prevalence estimations, LSD affected differently the three agro-climatic zones considered. Herd level seroprevalence was higher in the midland agro-climate zone 64% (95% CI: 53-74) as compared to the highland 26% (95% CI: 17-36) and the lowland 50% (95% CI: 40-60) agro-climates. Animal level seroprevalence in infected herds was also higher in the midland agro-climate zone 31% (95% CI: 24-40) than in the highland and lowland zones (24% (95% CI: 18-31) and 23% (95% CI: 18-29), respectively). Higher ICC value in the highland agro-climate zone implies that increased sample sizes should be particularly required for this zone in future studies to estimate LSD prevalence or incidence with a desired precision level. This seroprevalence study also suggests that the prevalence of LSD infection in Ethiopia is higher than what has been previously reported. In the light of these updated estimations, we discuss options to trigger appropriate control measures in the future.
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