Recent research has shown that invasive animals can pose a significant threat to wildlife and human health. Two reasons for this are that invaders can introduce novel parasites from their home ranges and because they can alter disease dynamics by serving as additional hosts. While these phenomena have been well documented worldwide, there are still many regions where we lack information on how invasions are altering parasite dynamics. In this study, I examined the impacts of animal invasions on parasite communities in the southeastern United States (Alabama, Florida, Georgia, Kentucky, Mississippi, North Carolina, South Carolina, and Tennessee). To assess the impacts of invaders, I downloaded records of chordate invaders from these states using data from the Invasive Species Specialist Group (n=70 species; 219 total records). With these invader records, I then searched the Host-Parasite Database (which has more than 250,000 host-helminth records) to determine what helminth species have been documented for these 70 hosts in their invaded range. Using these two sources, I then examined all combined records to determine how often hosts introduced new diseases, picked up diseases from invaded communities, and were carriers for zoonotic parasites that could influence human health.
Results/Conclusions
With these two search parameters, I found parasite records for 8 of the 70 animals (4 birds, 2 fish, and 2 mammals) in their invaded ranges, which suggests that we currently have limited amounts of data on how invasive species are altering parasite dynamics in the southeastern US. Interestingly, I also found no records of introductions of helminth parasites by the invaders, which may indicate that invaders may not introduce parasites as commonly has been suggested (at least in the case of helminths). Finally, I also determined that 4 of the 8 species were hosts to zoonotic helminths in their invaded range. This finding could indicate that invasive species could alter dynamics of parasites that could impact human health and could increase the likelihood of spillover by serving as additional hosts. Collectively, these findings indicate that invasive species can alter disease dynamics in native communities, but that we are severely lacking data to accurately assess their overall impact.