Control measures to prevent the increase of paratuberculosis prevalence in dairy cattle herds: an individual-based modelling approach
Authored by Guillaume Camanes, Alain Joly, Christine Fourichon, Romdhane Racem Ben, Pauline Ezanno
Date Published: 2018
DOI: 10.1186/s13567-018-0557-3
Sponsors:
French National Research Agency (ANR)
Platforms:
C++
Model Documentation:
Other Narrative
Flow charts
Mathematical description
Model Code URLs:
Model code not found
Abstract
Paratuberculosis, a gastrointestinal disease caused by Mycobacterium
avium subsp. paratuberculosis (Map), can lead to severe economic losses
in dairy cattle farms. Current measures are aimed at controlling
prevalence in infected herds, but are not fully effective. Our objective
was to determine the most effective control measures to prevent an
increase in adult prevalence in infected herds. We developed a new
individual-based model coupling population and infection dynamics.
Animals are characterized by their age (6 groups) and health state (6
states). The model accounted for all transmission routes and two control
measures used in the field, namely reduced calf exposure to adult faeces
and test-and-cull. We defined three herd statuses (low, moderate, and
high) based on realistic prevalence ranges observed in French dairy
cattle herds. We showed that the most relevant control measures depend
on prevalence. Calf management and test-and-cull both were required to
maximize the probability of stabilizing herd status. A reduced calf
exposure was confirmed to be the most influential measure, followed by
test frequency and the proportion of infected animals that were detected
and culled. Culling of detected high shedders could be delayed for up to
3 months without impacting prevalence. Management of low prevalence
herds is a priority since the probability of status stabilization is
high after implementing prioritized measures. On the contrary, an
increase in prevalence was particularly difficult to prevent in moderate
prevalence herds, and was only feasible in high prevalence herds if the
level of control was high.
Tags
Dynamics
Infection
Risk
Diagnosis
compartmental model
transmission
Avium subsp paratuberculosis
Johnes-disease
Economic consequences
Control programs
Regional-scale