Unravelling the ecological structure of emerging plant pathogens persisting in multi-host systems is challenging. In such systems, observations are often heterogeneous with respect to time, space and ...host species, and may lead to biases of perception. The biased perception of pathogen ecology may be exacerbated by hidden fractions of the whole host population, which may act as infection reservoirs.
We designed a mechanistic-statistical approach to help understand the ecology of emerging pathogens by filtering out some biases of perception. This approach, based on SIR (Susceptible–Infected–Removed) models and a Bayesian framework, disentangles epidemiological and observational processes underlying temporal counting data.
We applied our approach to French surveillance data on Xylella fastidiosa, a multi-host pathogenic bacterium recently discovered in Corsica, France. A model selection led to two diverging scenarios: one scenario without a hidden compartment and an introduction around 2001, and the other with a hidden compartment and an introduction around 1985.
Thus, Xylella fastidiosa was probably introduced into Corsica much earlier than its discovery, and its control could be arduous under the hidden compartment scenario. From a methodological perspective, our approach provides insights into the dynamics of emerging plant pathogens and, in particular, the potential existence of infection reservoirs.
Identifying and tracking equines are key activities in equine health prevention. France is one of the few European countries with an operational centralized database that records information on ...equines, owners, and keepers but not on the location and keeping conditions of equines. The objective of our study was to collect information on keeping habits of equines and the relative location of a wide range of equines, owners, and keepers and discuss their implication for surveillance and control of outbreak improvement. A national email survey was conducted among the 1.9% of people registered as owners and 8.2% of people registered as keepers in the French national equine identification database having given their agreement to be contacted by email. It led to the collection of information from 728 owners, 121 keepers, and 2,669 owner–keepers. Most of them housed their equines in a single
commune
(smallest geographic administrative unit in France) at their home as private individuals. The distance between the
communes
of residence and of holding was, in most cases (including 79% of owners in the owner survey, 89.5% of the keepers in the keeper survey, and about 94% of the owner–keepers in both surveys), less than 30 km. More than half of the keepers kept a maximum of five equines and the majority with two different uses/destinations together, mostly leisure-retirement, leisure-breeding, leisure-sport, and sport-breeding. The main limitation of the study was that a relatively limited number of people (
n
= 3518) were reachable due to the low availability of an email address and contact agreement. Nonetheless, the findings provide an overview of how equines are kept by non-professional owners and keepers and complements information usually collected by the French riding institute. Additionally, information collected is very helpful to determine a realistic estimate of the spatial distribution of equines in France. This information is very important for the equine sector, for demographic knowledge and also improvement of surveillance plans and control measures and for the management and monitoring of health events to limit the spread of diseases.
Accurate demographic knowledge of the equine population is needed to assess and model equine health events. France is one of the few European countries with an operational centralized database (SIRE) ...recording individual data on all declared equines living in France and on their owners and keepers. Our study aimed to assess SIRE database quality concerning the updating of information by equine owners and keepers with a view to its improvement and use in surveillance and research. Two online surveys were conducted with the participation of 6244 registered keepers and 13,869 owners. Results showed some inconsistencies between SIRE records and survey responses. The inconsistency rate for equines whose castration and death were not registered in the database was 28.7% and 5.9% respectively. Concerning owners, 11% of respondents did not own the reference equine selected considered by the survey, 33% had changed address without updating it in the SIRE. Concerning premises hosting equines, the keeper survey's inconsistency rate was 7.3%, of which 57 respondents had closed and 32 had opened premises without reporting it. Comparatively, the owner survey's inconsistency rate was 40.7% including respondents who owned and hosted an equine without reporting these equine premises, and owners who did not keep any equines on their premises. In conclusion, the SIRE database proved to be a valuable and reliable source for epidemiological research as long as some bias is taken into account. On the contrary, its use in surveillance is currently limited due some shortcomings in updating and/or reporting by owners and keepers.
•The SIRE database is a valuable source for epidemiological studies.•Some biases must be taken into account during epidemiological modeling.•Better reporting of equine deaths should be strongly encouraged.•Regular updating of contact details by keepers would be a major improvement.
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