First record of Spirometra erinaceieuropaei spargana infection in amphibians of South Asia: a causative agent of surficial abnormalities

Background: Sparganosis is a zoonotic disease caused by Plerocercoid larvae (spargana) of the genus Spirometra. We aimed to provide molecular evidence for the infection of amphibians with Spirometra sp. in the inside and outside of Horton Plains National Park (HPNP), Sri Lanka. Methods: The prevalence of sparganum infection in wild frogs (Truga eques and Minverya agricola) was investigated in the inside and outside of HPNP from June 2019 to April 2021. A total of 1,434 Amphibians samples were surveyed to examine the spargana infection from the study site. To identify the species identity of the collected spargana, a portion of the mitochondrial cytochrome c oxidase subunit 1 (cox1) gene and nuclear 18S rRNA gene were amplified, sequenced, and analyzed. Results: A total of 539 infected amphibians (T. eques and M. agricola) samples were examined to survey from the study area. Spargana were detected in all dissected specimens belonging to the species Spirometra erinaceieuropaei that were genetically confirmed using the evolutionary conserved nuclear 18S rRNA gene and then compared to the GenBank deposit, indicating that S. erinaceieuropaei is the primary causal agent of sparganosis both inside and outside the HPNP. Conclusion: Our finding is the first genetically confirmed record of S. erinaceieuro-paei in amphibians in South Asia. However, further studies are needed to investigate the prevalence of sparagna infection in amphibians all over the island.