Spatially limited pathogen pollution in an invasive tick and host system.

Expansion of global commerce has facilitated pathogen pollution via the transportation and translocation of invasive species and their associated parasites and pathogens. In Florida, imported cane toads (Rhinella horribilis) were accidentally and intentionally released on multiple occasions. Early populations were found to be infested with the invasive tick, Amblyomma rotundatum, yet it is unknown if these ticks dispersed with their hosts as cane toads spread throughout much of the state. The objectives of our investigation were to (1) determine if there are fewer tick infestations on toads at the periphery than at the core of their distribution as predicted by founder effect events, and (2) identify if ticks were infected with exotic pathogens. We captured toads from 10 populations across Florida. We collected ticks, vent tissue, and tick attachment site tissue from each toad, then tested samples for bacteria in the genus, Rickettsia. We found that 3/10 populations had toads that were infested with A. rotundatum, and infested individuals were in the earliest introduced populations at the core of their distribution. Pathogen testing confirmed Rickettisa bellii in ticks, but not in toad tissues. Haplotype networks could not clearly distinguish if R. bellii in Florida was more closely related to North or South American strains, but host-tick associations suggest that the pathogen was exotic to Florida. Our investigation demonstrated that an invasive species facilitated the introduction of parasites and pathogens into Florida, yet the invasive tick species encountered limitations to dispersal on this host species. Supplementary Information: The online version contains supplementary material available at 10.1007/s10530-024-03291-9.

The East Indies reptile tick Amblyomma helvolum Koch, 1844 (Acari: Ixodidae), taxonomy, biology and new host records, including the first record of human infestation.

Amblyomma helvolum is a widespread, generalist ectoparasite of reptiles in the oriental region, and has the potential to become highly invasive should it be inadvertently introduced outside its native range through the exotic pet trade. All life stages of A. helvolum are re-characterised morphologically and the first examples of nanism (dwarfism) and gynandromorphy (male and female tissue in one animal) for the species are described. Eighteen new hosts records are presented for A. helvolum, including the first case of human infestation. The taxonomy, distribution, ecology, phenology, disease associations, and invasion biology of the species are also discussed.