First Report of Co-invasion by the Reptile Nematode Ozolaimus megatyphlon (Nematoda: Pharyngodonidae) with Invasive Green Iguanas (Iguana iguana) in the Asia–Pacific



Co-invasion of naïve ecosystems by non-native parasites is a serious threat to global biodiversity, though such events are difficult to detect early in the invasion process. Green iguanas (Iguana iguana) are an emerging invasive species and have colonised several countries in the Asia–Pacific. A survey was undertaken to determine whether parasites of the green iguana had co-invaded naïve ecosystems with their introduced host.


Over a 10-month period, wild green iguanas were trapped and euthanised in Singapore. All animals were necropsied and sampled for parasites. Parasites were then identified morphologically and subsequently characterised molecularly at the cytochrome c oxidase I (COI) locus.


The reptile nematode Ozolaimus megatyphlon was found in 38% of the sampled green iguanas, with burdens of 100 + worms in all infected animals. This represents the first recorded co-invasion of this species with wild green iguanas in the Asia–Pacific. Based on the molecular characterisation of the cytochrome c oxidase I (COI) locus, the first DNA barcode is provided for O. megatyphlon.


For the first time, the reptile nematode Ozolaimus megatyphlon is shown to be invasive and to have colonised the Asia–Pacific region with its introduced host, the green iguana. The DNA barcode provided here will facilitate future monitoring programmes as O. megatyphlon invades new habitats and countries.

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The authors also thank the two anonymous reviewers for valuable comments which greatly enhanced this manuscript.

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Correspondence to Mackenzie L. Kwak.

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All applicable international, national and/or institutional guidelines for the care and use of animals were followed. All animals in this study were wild-caught invasive pest species euthanised in accordance with the guidelines set out in the animal welfare and ethics policy of Wildlife Reserves Singapore.

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Kwak, M.L., Lee, L., Okumura, C. et al. First Report of Co-invasion by the Reptile Nematode Ozolaimus megatyphlon (Nematoda: Pharyngodonidae) with Invasive Green Iguanas (Iguana iguana) in the Asia–Pacific. Acta Parasit. 65, 264–270 (2020).

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  • Invasive parasite
  • Invasive species
  • Pet trade
  • Exotic pets
  • Pinworm
  • Singapore