Intranuclear Coccidiosis in Tortoises (TINC) in Europe: A Retrospective Study 2022-2024

Abstract Testudine intranuclear coccidiosis (TINC) infects a wide range of chelonian species and can cause systemic disease and death. Samples submitted for TINC detection by PCR to a commercial diagnostic laboratory in Germany between 2022 and 2024 were retrospectively evaluated. Of 325 samples tested, 47 (14.46%) were positive for TINC, including 40 Testudinidae (of 269 tested, 14.87%) and seven of unknown species (of 34, 20.59%), while none of the samples submitted from other families (n = 22) tested positive. The highest detection rates were found in Burmese star tortoises ( Geochelone platynota ; 7/15, 46.7% positive), Hermann’s tortoises ( Testudo hermanni ; 3/13, 23.1%), and radiated tortoises ( Astrochelys radiate ; 8/36, 22.2%). Positive samples were submitted from Austria, Belgium, Czech Republic, Germany, Hungary, Italy, Netherlands, Spain, and the United Kingdom. Co-infection with TINC and mycoplasma was detected in 15 animals (n = 207 tested for both), co-infection with a herpesvirus and TINC was detected in three (n = 188), and co-infection with a torchivirus and TINC was detected in two (n = 123) animals. The TINC detection rate was significantly higher than that previously reported in Europe for 2014-2015 (47/325, 14.5% compared to 27/1,010, 2.7%; P < 0.001). TINC is detected regularly in diagnostic samples from tortoises in managed care in Europe and should be considered as a differential diagnosis for non-specific disease and for quarantine examinations in these animals.