Data from: Tick-borne disease risk in a forest food web

Changes to the community ecology of hosts for zoonotic pathogens,
particularly rodents, are likely to influence the emergence and prevalence
of zoonotic diseases worldwide. However, the complex interactions between
abiotic factors, pathogens, vectors, hosts, and both food resources and
predators of hosts are difficult to disentangle. Here we (1) use 19 years
of data from six large field plots in southeastern New York to compare the
effects of hypothesized drivers of interannual variation in Lyme disease
risk, including the abundance of acorns, rodents, and deer, as well as a
series of climate variables; and (2) employ landscape epidemiology to
explore how variation in predator community structure and forest cover
influences spatial variation in the infection prevalence of ticks for the
Lyme disease bacterium, Borrelia burgdorferi, and two other important
tick-borne pathogens, Anaplasma phagocytophilum and Babesia microti.
Acorn-driven increases in the abundance of mice were correlated with a
lagged increase in the abundance of questing nymph-stage Ixodes scapularis
ticks infected with Lyme disease bacteria. Abundance of white-tailed deer
two years prior also correlated with increased density of infected nymphal
ticks, although the effect was weak. Density of rodents in the current
year was a strong negative predictor of nymph density, apparently because
high current abundance of these hosts can remove nymphs from the
host-seeking population. Warm, dry spring or winter weather was associated
with reduced density of infected nymphs. At the landscape scale, the
presence of functionally diverse predator communities or of bobcats, the
only obligate carnivore, was associated with reduced infection prevalence
of I. scapularis nymphs with all three zoonotic pathogens. In the case of
Lyme disease, infection prevalence increased where coyotes were present
but smaller predators were displaced or otherwise absent. For all
pathogens, infection prevalence was lowest when forest cover within a 1km
radius was high. Taken together, our results suggest that a food web
perspective including bottom-up and top-down forcing is needed to
understand drivers of tick-borne disease risk, a result that may also
apply to other rodent-borne zoonoses. Prevention of exposure based on
ecological indicators of heightened risk should help protect public
health.