Evaluating potential effects of climate change on off-host tick ecology in Panama

Introduction: In tropical regions, global climate change promotes longer dry seasons and shorter wet seasons, with increasing importance to vector-borne disease transmission. The consequences of climate change for tick distributions in Central America have received scant attention, despite the presence of several important tick-borne diseases. This study evaluates potential impacts of climate change on survival, abundance, and diversity of nymph and adult ticks in Panama.

Methods: Field efforts were conducted at three sites along a natural precipitation gradient across Panama. This gradient was used as a proxy for climate change, with conditions at the driest site representing the predicted result of climate change for the wetter regions and the moderate precipitation site acting as a transition state. In addition to conducting weekly abundance surveys at these sites, I established survival enclosures containing nymph and adult ticks at these sites and monitored their survival weekly.

Results/Discussion: Results indicate that adult and nymph tick survival is lowest at the dry site while abundance is highest at the moderate precipitation site. Survival is similar at both the high and moderate precipitation sites.  The primary predicted result of climate change in the neotropics is an increase in dry conditions. This prediction suggests that one short-term impact of climate change in Panama may be an increase in tick abundance and survival as the high precipitation site transitions to moderate precipitation. This has powerful implications for public health efforts in assessing current disease risk and predicting how disease dynamics may shift due to climate change.