Ticks (Acari: Ixodidae) and tickborne pathogens (Rickettsiales) associated with hosts at Zoo Miami

Incidence of tickborne diseases is increasing in the United States, with nearly half a million cases estimated to occur annually. The rising burden of tickborne disease in the United States underscores the need to investigate the presence and prevalence of tick species and associated pathogens. Southern Florida serves as an introductory point for non-native invasive reptiles, amphibians, and ectoparasites due to the region's international ports and tropical climate. At Zoo Miami, visitors are near exhibit animals and free-living invasive species, including cane toads and green iguanas. This study identified ticks removed from reptiles and amphibians at Zoo Miami and analyzed these ticks for bacteria in the order Rickettsiales. 309 ticks were collected over a 2-year period (October 2022 to November 2024; Amblyomma dissimile Koch, 1844 (266/309), Amblyomma rotundatum Koch, 1844 (41/309), and A. tuberculatum Marx, 1894 (2/309). Rickettsia spp. DNA (Rickettsiales: Rickettsiaceae) was identified in A. dissimile (4.14%) and A. rotundatum (4.88%), including a Rickettsia species similar to several strains of R. parkeri based on a portion of the ompA gene. Three ticks contained Anaplasmataceae DNA (Rickettsiales: Anaplasmataceae), including 1 Ehrlichia chaffeensis-positive A. rotundatum, and 1 A. dissimile containing E. canis-like DNA. This study represents the first report to jointly describe ticks and their rickettsial bacteria from Zoo Miami, including novel host records for A. dissimile and A. rotundatum. Paired with identification of an ehrlichial pathogen, these novel host associations highlight the importance of tick surveillance for pathogens of public health concern in zoos and other animal facilities in southern Florida.