title: Estimating the potential impact of canine distemper virus on the Amur tiger population (Panthera tigris altaica) in Russia.
abstract: Lethal infections with canine distemper virus (CDV) have recently been diagnosed in Amur tigers (Panthera tigris altaica), but long-term implications for the population are unknown. This study evaluates the potential impact of CDV on a key tiger population in Sikhote-Alin Biosphere Zapovednik (SABZ), and assesses how CDV might influence the extinction potential of other tiger populations of varying sizes. An individual-based stochastic, SIRD (susceptible-infected-recovered/dead) model was used to simulate infection through predation of infected domestic dogs, and/or wild carnivores, and direct tiger-to-tiger transmission. CDV prevalence and effective contact based on published and observed data was used to define plausible low- and high-risk infection scenarios. CDV infection increased the 50-year extinction probability of tigers in SABZ by 6.3% to 55.8% compared to a control population, depending on risk scenario. The most significant factors influencing model outcome were virus prevalence in the reservoir population(s) and its effective contact rate with tigers. Adjustment of the mortality rate had a proportional impact, while inclusion of epizootic infection waves had negligible additional impact. Small populations were found to be disproportionately vulnerable to extinction through CDV infection. The 50-year extinction risk in populations consisting of 25 individuals was 1.65 times greater when CDV was present than that of control populations. The effects of density dependence do not protect an endangered population from the impacts of a multi-host pathogen, such as CDV, where they coexist with an abundant reservoir presenting a persistent threat. Awareness of CDV is a critical component of a successful tiger conservation management policy.
authors.affiliation: Wildlife Conservation Society, Bronx, New York, United States of America; Boyd Orr Centre for Population and Ecosystem Health, Institute of Biodiversity, Animal Health and Comparative Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom.
authors.forename: Martin
authors.initials: M
authors.lastname: Gilbert
authors.affiliation: Wildlife Conservation Society, Bronx, New York, United States of America.
authors.forename: Dale G
authors.initials: DG
authors.lastname: Miquelle
authors.affiliation: Panthera, New York, New York, United States of America.
authors.forename: John M
authors.initials: JM
authors.lastname: Goodrich
authors.affiliation: Boyd Orr Centre for Population and Ecosystem Health, Institute of Biodiversity, Animal Health and Comparative Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom.
authors.forename: Richard
authors.initials: R
authors.lastname: Reeve
authors.affiliation: Boyd Orr Centre for Population and Ecosystem Health, Institute of Biodiversity, Animal Health and Comparative Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom.
authors.forename: Sarah
authors.initials: S
authors.lastname: Cleaveland
authors.affiliation: Boyd Orr Centre for Population and Ecosystem Health, Institute of Biodiversity, Animal Health and Comparative Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom.
authors.forename: Louise
authors.initials: L
authors.lastname: Matthews
authors.affiliation: Wildlife Conservation Society, Bronx, New York, United States of America; Metabiota, San Francisco, California, United States of America.
authors.forename: Damien O
authors.initials: DO
authors.lastname: Joly
mesh_terms: D000818:Animals; D004197:Disease Reservoirs; D004216:Distemper / Q000453:epidemiology* / Q000635:transmission / Q000821:virology; D004217:Distemper Virus, Canine / Q000502:physiology*; D004285:Dogs; D056727:Endangered Species; D053476:Extinction, Biological; D005260:Female; D008098:Litter Size; D008954:Models, Biological; D012425:Russia (Pre-1917); D016019:Survival Analysis; D046010:Tigers