Background and Aim: Paramphistomiasis is common in tropical countries such as Indonesia and affects livestock and various endemic wild animals such as Sumatran elephants. However, the specific species of paramphistomoid worm that causes paramphistomiasis are rarely reported. The study aims at identifying paramphistomoid worm that infects Sumatran elephants.

Materials and Methods: Flukes were collected from the feces of five semi-captive Sumatran elephants that lived at Tegal Yoso Elephant Response Unit in Way Kambas National Park, in 2018, after treatment of oxyclozanide 1 g at the dose of approximately 5-8 mg/kg of body weight. Eight paramphistomoid worms were flattened and stained in Semichon's carmine for morphological identification, and five other worms were used for molecular identification at second internal transcribed spacer (ITS-2) of ribosomal deoxyribonucleic acid sequence.

Results: Forty-five flukes were collected from five Sumatran elephants in Lampung, Indonesia. Eight paramphistomoid worms were morphologically identified as Pfenderius heterocaeca> and five isolates did not show any variation in ITS-2. Phylogenetic analysis showed that there was a close genetic relationship between our sample and Chiorchis fabaceus that had a family similar to the samples.

Conclusion: Based on the morphological and molecular characteristics, the paramphistomoids found in Sumatran elephant on Way Kambas National Park are P. heterocaeca.

Keywords: internal transcribed spacer-2, paramphistomiasis, Pfenderius spp., Sumatran elephant.