First record of Isospora amphiboluri in the thorny devil, Moloch horridus

Abstract

Poor long-term survival (Mean = 2.16 y; 95% CI 1.68–2.65) was identified in a captive population of thorny devils (Moloch horridus) held at the Alice Springs Desert Park in the Northern Territory, Australia, over a period of 27 years. There was no significant difference in survival time (after acquisition) of wild-caught individuals compared captive born animals, or males compared to females. Limited information was available regarding the cause(s) of death for animals found dead or euthanased. Health of the live population at the time of the study (n = 14) was assessed by clinical history review, physical examination, and faecal examination. Large numbers of coccidian oocysts measuring 20–24 μm in diameter were identified upon faecal examination. Molecular investigation of genomic DNA from these samples identified Isospora amphiboluri based on the sequences of partial regions of the mitochondrial cytochrome c oxidase subunit 1 gene (cox1) and the nuclear small subunit of ribosomal RNA gene (SSU). Isospora amphiboluri was originally described from the bearded dragon (Pogona barbata) and has since been recorded in the inland bearded dragon (Pogona vitticeps) and the central netted dragon (Ctenophorus nuchalis). The present case expands the host range for I. amphiboluri. Histological examination of tissues was not available, and therefore the potential role of I. amphiboluri in morbidity and mortality of M. horridus is not clear. Further research is required to understand if colonization with I. amphiboluri is pathogenic in this species.