Landscape Genetics: A Toolbox for Studying Vector-Borne Diseases

Abstract

Landscape genetics aims to quantify the effect of landscape on gene flow. Broadly, the approach involves measuring genetic variation, quantifying landscape heterogeneity, and statistically testing the link between both genetic variation and landscape heterogeneity. This approach has been widely used by conservation biologists, for example to identify barriers restricting movement in threatened populations. More recently, landscape genetics has been used to study the epidemiology of infectious diseases, such as chronic wasting disease, raccoon rabies, and malaria. This method can be useful in identifying potential hotspot areas of disease movement for targeted public health interventions and containment of disease and drug resistance. However, vector-borne disease epidemiology is particularly complex, as it is affected by the movement of both the vector and human or vertebrate host. This feature could potentially inhibit the ability to detect the effect of landscape on gene flow, since the ecology of vectors and hosts are likely different and potentially conflicting. Here, we provide a summary of the latest innovations in the field of landscape genetics with a focus on those that could help increase the power to detect landscape effects in vector-borne human disease studies. We also provide a recommended framework for studying vector-borne diseases using a landscape genetics approach. Landscape genetics has the potential to be a powerful tool for the field of vector-borne disease epidemiology but has so far been underutilized. The provided synthesis of tools and considerations for conducting a landscape genetics study of a vector-borne disease aim to bridge the gap between the two disciplines.

Comparative landscape genetics reveals differential effects of environment on host and pathogen genetic structure in Tasmanian devils (Sarcophilus harrisii) and their transmissible tumour

“…Examples include sarcoptic mange, which infects various mammal species and can be transmitted environmentally (Martin, Ricardo, et al, 2019;Niedringhaus, Brown, Sweeley, & Yabsley, 2019), or pathogens requiring arthropod vectors, such as Plasmodium spp. (malaria; Lo et al, 2017), whereby disease spread relies on multiple species and is strongly mediated by the environment (Hemming-Schroeder et al, 2018;Schwabl et al, 2017).…”

“…Further, there is often uncertainty as to whether observed contacts and movements reflect actual pathogen transmission and spread (Craft, 2015). In contrast, the spatial distribution of genetic variation contains signatures of past dispersal (in the case of the host) or spread (in the case of the pathogen) and often can be linked with environmental or ecological factors at fine spatial scales (Archie, Luikart, & Ezenwa, 2009;Biek & Real, 2010;Blanchong, Robinson, Samuel, & Foster, 2016;Hemming-Schroeder, Lo, Salazar, Puente, & Yan, 2018;Kozakiewicz et al, 2018). Knowledge of these relationships is critical to predicting the spread of wildlife diseases and can inform management strategies aimed at mitigating their impact.…”

“…Cleary, Waits, & Finegan, 2017;Goldberg & Waits, 2010;Petren, Grant, Grant, & Keller, 2005;Trumbo, Spear, Baumsteiger, & Storfer, 2013;Zancolli, Rödel, Steffan-Dewenter, & Storfer, 2014). Even fewer multispecies studies have employed landscape genetics methods to study the dynamics of infectious diseases in wildlife systems (Biek & Real, 2010;Hemming-Schroeder et al, 2018;Kozakiewicz et al, 2018). Such comparative landscape genetics frameworks can provide valuable insights into how host-pathogen interactions shape patterns of disease transmission and spread across heterogeneous landscapes (Leo, Gonzalez, Millien, & Cristescu, 2016;Schwabl et al, 2017;Talbot et al, 2017).…”

Landscape Genetics: From Classic Molecular Markers to Genomics

“…Landscape genetics also has been employed in epidemiological studies of human diseases. Statistical methods can be used in the identification of hotspot areas of disease movement [40]. This will have important implications in designing strategies for spread containment.…”

“…This will have important implications in designing strategies for spread containment. One challenge, however, has been the application of landscape genetics methods in vector-borne diseases, which was reviewed by Hemming-Schroeder [40]. A few studies have been dedicated to such goal with human diseases.…”