Absence of evidence is not evidence of absence: Feral pigs as vectors of soil-borne pathogens

Cheryl Krull, Nick Waipara, David CHOQUENOT, Bruce Burns, Andrew Gormley, Margaret Stanley

    Research output: Contribution to journalArticle

    15 Citations (Scopus)

    Abstract

    Invasive soil-borne pathogens are a major threat to forest ecosystems worldwide.The newly discovered soil pathogen, Phytophthora ‘taxon Agathis’ (PTA), is a serious threat to endemic kauri (Agathis australis: Araucariaceae) in New Zealand. This study examined the potential for feral pigs to act as vectors of PTA.We investigated whether snouts and trotters of feral pigs carry soil contaminated with PTA, and using these results determined the probability that feral pigs act as a vector.We screened the soil on trotters and snouts from 457 pigs for PTA using various baiting techniques and molecular testing. This study detected 19 species of plant pathogens in the soil on pig trotters and snouts, including a different Phytophthora species (Phytophthora cinnamomi). However, no PTA was isolated from the samples. A positive control experiment showed a test sensitivity of 0–3% for the baiting methods and the data obtained were used in a Bayesian probability modelling approach.This showed a posterior probability of 35–90% (dependent on test sensitivity scores and design prevalence) that pigs do vector PTA and estimated that a sample size of over 1000 trotters would be required to prove a negative result.We conclude that feral pigs cannot be ruled out as a vector of soil-based plant pathogens and that there is still a high probability that feral pigs do vector PTA, despite our negative results.We also highlight the need to develop a more sensitive test for PTA in small soil samples associated with pigs due to unreliable detection rates using the current method.
    Original languageEnglish
    Pages (from-to)534-542
    Number of pages9
    JournalAustral Ecology
    Volume38
    DOIs
    Publication statusPublished - 2013

    Fingerprint

    Agathis (Araucariaceae)
    Phytophthora
    pig
    pathogen
    swine
    pathogens
    soil
    Agathis australis
    baiting
    plant pathogens
    testing
    Araucariaceae
    Phytophthora cinnamomi
    polluted soils
    forest ecosystems
    forest ecosystem
    soil sampling
    methodology
    sampling

    Cite this

    Krull, Cheryl ; Waipara, Nick ; CHOQUENOT, David ; Burns, Bruce ; Gormley, Andrew ; Stanley, Margaret. / Absence of evidence is not evidence of absence: Feral pigs as vectors of soil-borne pathogens. In: Austral Ecology. 2013 ; Vol. 38. pp. 534-542.
    @article{7e86ab84c0f44ce8a66e66e435d63edf,
    title = "Absence of evidence is not evidence of absence: Feral pigs as vectors of soil-borne pathogens",
    abstract = "Invasive soil-borne pathogens are a major threat to forest ecosystems worldwide.The newly discovered soil pathogen, Phytophthora ‘taxon Agathis’ (PTA), is a serious threat to endemic kauri (Agathis australis: Araucariaceae) in New Zealand. This study examined the potential for feral pigs to act as vectors of PTA.We investigated whether snouts and trotters of feral pigs carry soil contaminated with PTA, and using these results determined the probability that feral pigs act as a vector.We screened the soil on trotters and snouts from 457 pigs for PTA using various baiting techniques and molecular testing. This study detected 19 species of plant pathogens in the soil on pig trotters and snouts, including a different Phytophthora species (Phytophthora cinnamomi). However, no PTA was isolated from the samples. A positive control experiment showed a test sensitivity of 0–3{\%} for the baiting methods and the data obtained were used in a Bayesian probability modelling approach.This showed a posterior probability of 35–90{\%} (dependent on test sensitivity scores and design prevalence) that pigs do vector PTA and estimated that a sample size of over 1000 trotters would be required to prove a negative result.We conclude that feral pigs cannot be ruled out as a vector of soil-based plant pathogens and that there is still a high probability that feral pigs do vector PTA, despite our negative results.We also highlight the need to develop a more sensitive test for PTA in small soil samples associated with pigs due to unreliable detection rates using the current method.",
    keywords = "Bayesian, invasive species, Phytophthora, PTA, vector.",
    author = "Cheryl Krull and Nick Waipara and David CHOQUENOT and Bruce Burns and Andrew Gormley and Margaret Stanley",
    year = "2013",
    doi = "10.1111/j.1442-9993.2012.02444.x",
    language = "English",
    volume = "38",
    pages = "534--542",
    journal = "Austral Ecology",
    issn = "1442-9985",
    publisher = "Wiley-Blackwell",

    }

    Krull, C, Waipara, N, CHOQUENOT, D, Burns, B, Gormley, A & Stanley, M 2013, 'Absence of evidence is not evidence of absence: Feral pigs as vectors of soil-borne pathogens', Austral Ecology, vol. 38, pp. 534-542. https://doi.org/10.1111/j.1442-9993.2012.02444.x

    Absence of evidence is not evidence of absence: Feral pigs as vectors of soil-borne pathogens. / Krull, Cheryl; Waipara, Nick; CHOQUENOT, David; Burns, Bruce; Gormley, Andrew; Stanley, Margaret.

    In: Austral Ecology, Vol. 38, 2013, p. 534-542.

    Research output: Contribution to journalArticle

    TY - JOUR

    T1 - Absence of evidence is not evidence of absence: Feral pigs as vectors of soil-borne pathogens

    AU - Krull, Cheryl

    AU - Waipara, Nick

    AU - CHOQUENOT, David

    AU - Burns, Bruce

    AU - Gormley, Andrew

    AU - Stanley, Margaret

    PY - 2013

    Y1 - 2013

    N2 - Invasive soil-borne pathogens are a major threat to forest ecosystems worldwide.The newly discovered soil pathogen, Phytophthora ‘taxon Agathis’ (PTA), is a serious threat to endemic kauri (Agathis australis: Araucariaceae) in New Zealand. This study examined the potential for feral pigs to act as vectors of PTA.We investigated whether snouts and trotters of feral pigs carry soil contaminated with PTA, and using these results determined the probability that feral pigs act as a vector.We screened the soil on trotters and snouts from 457 pigs for PTA using various baiting techniques and molecular testing. This study detected 19 species of plant pathogens in the soil on pig trotters and snouts, including a different Phytophthora species (Phytophthora cinnamomi). However, no PTA was isolated from the samples. A positive control experiment showed a test sensitivity of 0–3% for the baiting methods and the data obtained were used in a Bayesian probability modelling approach.This showed a posterior probability of 35–90% (dependent on test sensitivity scores and design prevalence) that pigs do vector PTA and estimated that a sample size of over 1000 trotters would be required to prove a negative result.We conclude that feral pigs cannot be ruled out as a vector of soil-based plant pathogens and that there is still a high probability that feral pigs do vector PTA, despite our negative results.We also highlight the need to develop a more sensitive test for PTA in small soil samples associated with pigs due to unreliable detection rates using the current method.

    AB - Invasive soil-borne pathogens are a major threat to forest ecosystems worldwide.The newly discovered soil pathogen, Phytophthora ‘taxon Agathis’ (PTA), is a serious threat to endemic kauri (Agathis australis: Araucariaceae) in New Zealand. This study examined the potential for feral pigs to act as vectors of PTA.We investigated whether snouts and trotters of feral pigs carry soil contaminated with PTA, and using these results determined the probability that feral pigs act as a vector.We screened the soil on trotters and snouts from 457 pigs for PTA using various baiting techniques and molecular testing. This study detected 19 species of plant pathogens in the soil on pig trotters and snouts, including a different Phytophthora species (Phytophthora cinnamomi). However, no PTA was isolated from the samples. A positive control experiment showed a test sensitivity of 0–3% for the baiting methods and the data obtained were used in a Bayesian probability modelling approach.This showed a posterior probability of 35–90% (dependent on test sensitivity scores and design prevalence) that pigs do vector PTA and estimated that a sample size of over 1000 trotters would be required to prove a negative result.We conclude that feral pigs cannot be ruled out as a vector of soil-based plant pathogens and that there is still a high probability that feral pigs do vector PTA, despite our negative results.We also highlight the need to develop a more sensitive test for PTA in small soil samples associated with pigs due to unreliable detection rates using the current method.

    KW - Bayesian

    KW - invasive species

    KW - Phytophthora

    KW - PTA

    KW - vector.

    U2 - 10.1111/j.1442-9993.2012.02444.x

    DO - 10.1111/j.1442-9993.2012.02444.x

    M3 - Article

    VL - 38

    SP - 534

    EP - 542

    JO - Austral Ecology

    JF - Austral Ecology

    SN - 1442-9985

    ER -