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Dynamics of host populations affected by the emerging fungal pathogen Batrachochytrium salamandrivorans

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ABSTRACT

Emerging infectious diseases cause extirpation of wildlife populations. We use an epidemiological model to explore the effects of a recently emerged disease caused by the salamander-killing chytrid fungus Batrachochytrium salamandrivorans (Bsal) on host populations, and to evaluate which mitigation measures are most likely to succeed. As individuals do not recover from Bsal, we used a model with the states susceptible, latent and infectious, and parametrized the model using data on host and pathogen taken from the literature and expert opinion. The model suggested that disease outbreaks can occur at very low host densities (one female per hectare). This density is far lower than host densities in the wild. Therefore, all naturally occurring populations are at risk. Bsal can lead to the local extirpation of the host population within a few months. Disease outbreaks are likely to fade out quickly. A spatial variant of the model showed that the pathogen could potentially spread rapidly. As disease mitigation during outbreaks is unlikely to be successful, control efforts should focus on preventing disease emergence and transmission between populations. Thus, this emerging wildlife disease is best controlled through prevention rather than subsequent actions.

No MeSH data available.


The effect of varying carrying capacity K on the minimal density reached by S (min (S), left y-axis) and time for S to reach min (S) (right y-axis).
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RSOS160801F1: The effect of varying carrying capacity K on the minimal density reached by S (min (S), left y-axis) and time for S to reach min (S) (right y-axis).

Mentions: In the case of a disease outbreak, for realistic values of K the trajectory connecting K at t0 to the equilibrium state reaches densities of almost zero adult females ha−1 (figure 1). The figure also shows the time needed for S to reach its minimal density, that is, the minimal density during the ‘population crash’; since we had to rely on the literature and expert opinion to parametrize our model, we gauged this approach to be more appropriate than using a threshold density. This minimum seems to be reached within two to three months.Figure 1.


Dynamics of host populations affected by the emerging fungal pathogen Batrachochytrium salamandrivorans
The effect of varying carrying capacity K on the minimal density reached by S (min (S), left y-axis) and time for S to reach min (S) (right y-axis).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5383822&req=5

RSOS160801F1: The effect of varying carrying capacity K on the minimal density reached by S (min (S), left y-axis) and time for S to reach min (S) (right y-axis).
Mentions: In the case of a disease outbreak, for realistic values of K the trajectory connecting K at t0 to the equilibrium state reaches densities of almost zero adult females ha−1 (figure 1). The figure also shows the time needed for S to reach its minimal density, that is, the minimal density during the ‘population crash’; since we had to rely on the literature and expert opinion to parametrize our model, we gauged this approach to be more appropriate than using a threshold density. This minimum seems to be reached within two to three months.Figure 1.

View Article: PubMed Central - PubMed

ABSTRACT

Emerging infectious diseases cause extirpation of wildlife populations. We use an epidemiological model to explore the effects of a recently emerged disease caused by the salamander-killing chytrid fungus Batrachochytrium salamandrivorans (Bsal) on host populations, and to evaluate which mitigation measures are most likely to succeed. As individuals do not recover from Bsal, we used a model with the states susceptible, latent and infectious, and parametrized the model using data on host and pathogen taken from the literature and expert opinion. The model suggested that disease outbreaks can occur at very low host densities (one female per hectare). This density is far lower than host densities in the wild. Therefore, all naturally occurring populations are at risk. Bsal can lead to the local extirpation of the host population within a few months. Disease outbreaks are likely to fade out quickly. A spatial variant of the model showed that the pathogen could potentially spread rapidly. As disease mitigation during outbreaks is unlikely to be successful, control efforts should focus on preventing disease emergence and transmission between populations. Thus, this emerging wildlife disease is best controlled through prevention rather than subsequent actions.

No MeSH data available.