Conclusions
While Lyme disease is a major public health concern and prevalence has
been increasing in the recent past, so has the incidence of many other
tickborne diseases (R. J. Eisen & Eisen, 2018; Rosenberg et al.,
2018). Understanding tick vectors, especially those like I.
scapularis which transmits multiple human pathogens, is important not
just in mitigating disease risk in humans, but to understanding these
complex ecological systems in a OneHealth context. This model disease
system has a complex taxonomic history and is intertwined with
vector-host-pathogen-environmental relationships that still are not
fully understood. The genetics of I. scapularis populations can
be correlated with disease prevalence but a direct phenotype-genotype
link had not yet been made. This study has built a foundation for
tracking the genetic background, and the shifts in them, that are
associated with higher disease transmission. Although the RAD loci
investigated here illuminate overall patterns and potential candidate
loci for further work, future whole genome resequencing studies ofI. scapularis individuals from populations across the geographic
range are needed to obtain a more complete picture of genomic
variability and characterization of candidate loci.
Identifying and monitoring genetic backgrounds associated with increased
occurrence of tickborne disease can provide a rapid snapshot tool for
assessing potential community risk. With this 3RAD approach, we
identified genomic regions that should be further studied to determine
how genetic diversity is related to behavioral differences among
Northern and Southern populations. By using our 3RAD approach, we can
examine consistent loci across the genome in many individual ticks,
which can be replicated in new I. scapularis populations to
continually add to this dataset. Having a database of trackable loci
associated with increased Lyme disease risk or prevalence could allow
public health officials to implement targeted, efficient, and thus
cost-effective, control strategies for distinct tick populations or
undertake public health awareness campaigns in at-risk communities
before they become an emerging hotspot for tickborne disease.