Limits...
A novel epidemiological model to better understand and predict the observed seasonal spread of Pestivirus in Pyrenean chamois populations.

Beaunée G, Gilot-Fromont E, Garel M, Ezanno P - Vet. Res. (2015)

Bottom Line: Our model adequately represents the system dynamics, observations and model predictions showing similar seasonal patterns.We show that the virus has a significant impact on population dynamics, and that persistently infected animals play a major role in the epidemic dynamics.Modeling the seasonal dynamics allowed us to obtain realistic prediction and to identify key parameters of transmission.

View Article: PubMed Central - PubMed

Affiliation: INRA, Oniris, LUNAM Université, UMR1300 BioEpAR, CS40706, F-44307 Nantes, France. gael.beaunee@gmail.com.

ABSTRACT
Seasonal variations in individual contacts give rise to a complex interplay between host demography and pathogen transmission. This is particularly true for wild populations, which highly depend on their natural habitat. These seasonal cycles induce variations in pathogen transmission. The seasonality of these biological processes should therefore be considered to better represent and predict pathogen spread. In this study, we sought to better understand how the seasonality of both the demography and social contacts of a mountain ungulate population impacts the spread of a pestivirus within, and the dynamics of, this population. We propose a mathematical model to represent this complex biological system. The pestivirus can be transmitted both horizontally through direct contact and vertically in utero. Vertical transmission leads to abortion or to the birth of persistently infected animals with a short life expectancy. Horizontal transmission involves a complex dynamics because of seasonal variations in contact among sexes and age classes. We performed a sensitivity analysis that identified transmission rates and disease-related mortality as key parameters. We then used data from a long-term demographic and epidemiological survey of the studied population to estimate these mostly unknown epidemiological parameters. Our model adequately represents the system dynamics, observations and model predictions showing similar seasonal patterns. We show that the virus has a significant impact on population dynamics, and that persistently infected animals play a major role in the epidemic dynamics. Modeling the seasonal dynamics allowed us to obtain realistic prediction and to identify key parameters of transmission.

No MeSH data available.


Related in: MedlinePlus

Predicted seasonal pattern of seroprevalence and viroprevalence. Plain line: seroprevalence; dashed line: viroprevalence.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
getmorefigures.php?uid=PMC4513621&req=5

Fig6: Predicted seasonal pattern of seroprevalence and viroprevalence. Plain line: seroprevalence; dashed line: viroprevalence.

Mentions: The headcount over time predicted by the model was in good agreement with observed data, the decrease in population size after virus introduction being reproduced by the model. The seasonal pattern for seroprevalence was still present (Figure 6). When we observed seasonal variations more closely over the course of one year, after the birthing period there was a decrease in seroprevalence for about three months followed by an increase until the next period of births. The values and dynamics obtained, while a little higher, were nearer to the observations than those of the preliminary simulations. There was a sharp rise in seroprevalence followed by a decline and stabilization that correspond to the inter-annual variations observed however with lower amplitude.Figure 6


A novel epidemiological model to better understand and predict the observed seasonal spread of Pestivirus in Pyrenean chamois populations.

Beaunée G, Gilot-Fromont E, Garel M, Ezanno P - Vet. Res. (2015)

Predicted seasonal pattern of seroprevalence and viroprevalence. Plain line: seroprevalence; dashed line: viroprevalence.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4513621&req=5

Fig6: Predicted seasonal pattern of seroprevalence and viroprevalence. Plain line: seroprevalence; dashed line: viroprevalence.
Mentions: The headcount over time predicted by the model was in good agreement with observed data, the decrease in population size after virus introduction being reproduced by the model. The seasonal pattern for seroprevalence was still present (Figure 6). When we observed seasonal variations more closely over the course of one year, after the birthing period there was a decrease in seroprevalence for about three months followed by an increase until the next period of births. The values and dynamics obtained, while a little higher, were nearer to the observations than those of the preliminary simulations. There was a sharp rise in seroprevalence followed by a decline and stabilization that correspond to the inter-annual variations observed however with lower amplitude.Figure 6

Bottom Line: Our model adequately represents the system dynamics, observations and model predictions showing similar seasonal patterns.We show that the virus has a significant impact on population dynamics, and that persistently infected animals play a major role in the epidemic dynamics.Modeling the seasonal dynamics allowed us to obtain realistic prediction and to identify key parameters of transmission.

View Article: PubMed Central - PubMed

Affiliation: INRA, Oniris, LUNAM Université, UMR1300 BioEpAR, CS40706, F-44307 Nantes, France. gael.beaunee@gmail.com.

ABSTRACT
Seasonal variations in individual contacts give rise to a complex interplay between host demography and pathogen transmission. This is particularly true for wild populations, which highly depend on their natural habitat. These seasonal cycles induce variations in pathogen transmission. The seasonality of these biological processes should therefore be considered to better represent and predict pathogen spread. In this study, we sought to better understand how the seasonality of both the demography and social contacts of a mountain ungulate population impacts the spread of a pestivirus within, and the dynamics of, this population. We propose a mathematical model to represent this complex biological system. The pestivirus can be transmitted both horizontally through direct contact and vertically in utero. Vertical transmission leads to abortion or to the birth of persistently infected animals with a short life expectancy. Horizontal transmission involves a complex dynamics because of seasonal variations in contact among sexes and age classes. We performed a sensitivity analysis that identified transmission rates and disease-related mortality as key parameters. We then used data from a long-term demographic and epidemiological survey of the studied population to estimate these mostly unknown epidemiological parameters. Our model adequately represents the system dynamics, observations and model predictions showing similar seasonal patterns. We show that the virus has a significant impact on population dynamics, and that persistently infected animals play a major role in the epidemic dynamics. Modeling the seasonal dynamics allowed us to obtain realistic prediction and to identify key parameters of transmission.

No MeSH data available.


Related in: MedlinePlus