Monitoring infection load of oxyurid (nematoda) and Isospora (coccidia) in captive inland bearded dragons (Pogona vitticeps)

Abstract

Endoparasites, such as helminths and protozoans, have been associated with mortality and gastrointestinal disease in reptiles, with particularly high prevalence observed in pet reptiles. We conducted an observational study on six juvenile captive inland bearded dragons (Pogona vitticeps), to monitor the presence and estimate the abundance of intestinal endoparasite via faecal samples (egg counts using modified McMaster) over three months. We detected two types of endoparasites, coccidia Isospora sp. and oxyurid Phyrngodon sp. Oxyurid nematode ova shed almost 2.5 times higher egg count per gram of faeces in the afternoon compared to the morning, but the estimated egg counts did not significantly vary from August to October 2023. In contrast, for Isospora, there was no difference in oocyst counts between the two times of day sampled, but the shedding of Isospora oocyst increased over the three months. Often Isospora sp. are recorded to be highly pathogenic and can cause mortality in juvenile reptiles, whereas oxyurid are regarded as beneficial to their host unless they are found in high burdens. In this study, we did not find any significant association between the estimated quantity of egg/oocyst and the body condition of the dragons during the three months. Further studies are required to investigate pathogenicity or benefit of oxyurid to their hosts at different development stages. Finally, the storage period between collection and egg/oocyst quantification varied in this study, which may affect the estimated count of the eggs or oocysts. However, we did not find any apparent influence on time when faecal samples were processed to the number of eggs/oocysts that we counted.