The certainty of uncertainty: potential sources of bias and imprecision in disease ecology studies
File(s)fvets-05-00090.pdf (1.72 MB)
Published version
Author(s)
Lachish, Shelly
Murray, KA
Type
Journal Article
Abstract
Wildlife diseases have important implications for wildlife and human health, the preservation of biodiversity and the resilience of
ecosystems. However, understanding disease dynamics and the impacts of pathogens in wild populations is challenging because
these complex systems can rarely, if ever, be observed without error. Uncertainty in disease ecology studies is commonly defined
in terms of either heterogeneity in detectability (due to variation in the probability of encountering, capturing, or detecting
individuals in their natural habitat) or uncertainty in disease state assignment (due to misclassification errors or incomplete
information). In reality, however, uncertainty in disease ecology studies extends beyond these components of observation error
and can arise from multiple varied processes, each of which can lead to bias and a lack of precision in parameter estimates. Here,
we present an inventory of the sources of potential uncertainty in studies that attempt to quantify disease-relevant parameters
from wild populations (e.g. prevalence, incidence, transmission rates, force of infection, risk of infection, persistence times, and
disease-induced impacts). We show that uncertainty can arise via processes pertaining to aspects of the disease system, the study
design, the methods used to study the system, and the state of knowledge of the system, and that uncertainties generated via one
process can propagate through to others because of interactions between the numerous biological, methodological and
environmental factors at play. We show that many of these sources of uncertainty may not be immediately apparent to
researchers (for example, unidentified crypticity among vectors, hosts or pathogens, a mismatch between the temporal scale of
sampling and disease dynamics, demographic or social misclassification), and thus have received comparatively little consideration
in the literature to date. Finally, we discuss the type of bias or imprecision introduced by these varied sources of uncertainty and
briefly present appropriate sampling and analytical methods to account for, or minimise, their influence on estimates of disease-
relevant parameters. This review should assist researchers and practitioners to navigate the pitfalls of uncertainty in wildlife
disease ecology studies.
ecosystems. However, understanding disease dynamics and the impacts of pathogens in wild populations is challenging because
these complex systems can rarely, if ever, be observed without error. Uncertainty in disease ecology studies is commonly defined
in terms of either heterogeneity in detectability (due to variation in the probability of encountering, capturing, or detecting
individuals in their natural habitat) or uncertainty in disease state assignment (due to misclassification errors or incomplete
information). In reality, however, uncertainty in disease ecology studies extends beyond these components of observation error
and can arise from multiple varied processes, each of which can lead to bias and a lack of precision in parameter estimates. Here,
we present an inventory of the sources of potential uncertainty in studies that attempt to quantify disease-relevant parameters
from wild populations (e.g. prevalence, incidence, transmission rates, force of infection, risk of infection, persistence times, and
disease-induced impacts). We show that uncertainty can arise via processes pertaining to aspects of the disease system, the study
design, the methods used to study the system, and the state of knowledge of the system, and that uncertainties generated via one
process can propagate through to others because of interactions between the numerous biological, methodological and
environmental factors at play. We show that many of these sources of uncertainty may not be immediately apparent to
researchers (for example, unidentified crypticity among vectors, hosts or pathogens, a mismatch between the temporal scale of
sampling and disease dynamics, demographic or social misclassification), and thus have received comparatively little consideration
in the literature to date. Finally, we discuss the type of bias or imprecision introduced by these varied sources of uncertainty and
briefly present appropriate sampling and analytical methods to account for, or minimise, their influence on estimates of disease-
relevant parameters. This review should assist researchers and practitioners to navigate the pitfalls of uncertainty in wildlife
disease ecology studies.
Date Issued
2018-05-22
Date Acceptance
2018-04-12
Citation
Frontiers in Veterinary Science, 2018, 5
ISSN
2297-1769
Publisher
Frontiers Media
Journal / Book Title
Frontiers in Veterinary Science
Volume
5
Copyright Statement
© 2018 Lachish and Murray. This is an open-access article distributed under
the terms of the Creative Commons Attribution License (CC BY). The use, distribution
or reproduction in other forums is permitted, provided the original author(s) and the
copyright owner are credited and that the original publication in this journal is cited,
in accordance with accepted academic practice. No use, distribution or reproduction is
permitted which does not comply with these terms.
the terms of the Creative Commons Attribution License (CC BY). The use, distribution
or reproduction in other forums is permitted, provided the original author(s) and the
copyright owner are credited and that the original publication in this journal is cited,
in accordance with accepted academic practice. No use, distribution or reproduction is
permitted which does not comply with these terms.
Sponsor
Medical Research Council (MRC)
Grant Number
MR/R015600/1
Subjects
Science & Technology
Life Sciences & Biomedicine
Veterinary Sciences
imperfect detection
state misclassification
sensitivity
specificity
wildlife disease
host-pathogen
prevalence
disease impacts
WEST-NILE-VIRUS
WILD BIRD POPULATION
DETECTION PROBABILITY
INFECTIOUS-DISEASES
IMPERFECT DETECTION
AMPHIBIAN PATHOGEN
ENDEMIC MALARIA
SOCIAL NETWORKS
PREVALENCE
PARASITE
Publication Status
Published
Article Number
ARTN 90