Hostname: page-component-8448b6f56d-dnltx Total loading time: 0 Render date: 2024-04-23T19:37:55.551Z Has data issue: false hasContentIssue false

A cost analysis of alternative culling strategies for the eradication of classical swine fever in wildlife

Published online by Cambridge University Press:  04 October 2007

LUCA BOLZONI
Affiliation:
Dipartimento di Scienze Ambientali, Università degli Studi di Parma, Viale Usberti 11/A, 43100 Parma, Italy. Tel: (+39) 0521-905 619. Fax: (+39) 0521-905 402. Email: luca.bolzoni@nemo.unipr.it
GIULIO A. DE LEO
Affiliation:
Dipartimento di Scienze Ambientali, Università degli Studi di Parma, Viale Usberti 11/A, 43100 Parma, Italy. Email: giulio.deleo@unipr.it

Abstract

In the epidemiological literature, the eradication of a wildlife disease through culling is usually described in terms of a constant hunting rate to simulate the selective removal of animals from the population. By using simple SI (susceptible–infected) models, it is easy to prove that, if the hunting rate is high enough, the population eventually drops below a critical threshold level under which the pathogen is deemed to be extinct. However, hunting costs as well as the monetary benefits of disease control are almost systematically neglected. Moreover, the hunting rate is usually assumed to be constant over time, while in reality health authorities can implement more flexible culling policies. In this work we examine a class of more realistic time-variant culling strategies in a cost–benefit framework. Culling strategies differ in the way decisions are made about when and how much to cull; that is, whether hunting occurs when disease prevalence, host population density, or the number of carcasses exceeds (or is below) a given threshold. For each culling strategy, the optimal value of the control parameters and the hunting rate are those that minimize the sum of the culling costs and the sanitary costs associated with infection over a specific period of time. Classical swine fever (CSF) in wild boar populations has been taken as a reference example because of its potential economic impact on industrialized and developing countries.

We show that the optimal time-flexible culling strategy is invariably more efficient than the best traditional strategy in which the hunting rate is held constant through time. We also show that the type of hunting strategy that is selected as optimal depends on the shape of the cost functions.

Type
Research Article
Copyright
2007 Cambridge University Press

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

Footnotes

The authors are very grateful to Anastasios Xepapadeas for the initial idea that led to this project, to Leslie Real for constructive discussions about disease control in wildlife, and to Scott Duke-Sylvester, Giulia Fiorese, Simone Vincenzi, Daniele Bevacqua and Andrea Piotti for their suggestions and remarks that improved the manuscript. This work was partially supported by the interlink project ‘Conseguenze e impatti dei cambiamenti climatici globali sulla gestione e conservazione delle risorse naturali’ (prot. II04CE49G8) of the Italian Ministry of University and Research.