Gastrointestinal apicomplexan parasites of captive reptiles: diversity, causes, consequences.

BACKGROUND: Captive reptiles frequently suffer from gastrointestinal parasites, which stem from their breeding conditions such as limited space and frequent contact with faeces, high numbers of individuals in inadequate conditions, stress, but also from extensive exports and imports in recent years. In particular, parasites with single-host life cycles are common as they can easily complete their development. This study focused on extensive sampling across a variety of captive reptiles groups including lizards (agamas, chameleons, geckos, iguanas, monitors, skinks), snakes, tortoises, and also crocodiles, originating from various resources (pet trades, private breeders, and zoos). RESULTS: Examination of faecal samples revealed that 17.9% (55/308) of captive reptiles were infected with coccidia, namely Eimeria (7.1%), Choleoeimeria (5.5%), Isospora (3.9%), and Caryospora (0.3%), and that 3.2% (10/308) were infected with Cryptosporidium. These apicomplexans, which have monoxenous life cycles, may easily be maintained in breedings, and commonly transmitted to the breedings of new owners via trades and expos. While Choleoeimeria spp. were most prevalent in snake hosts, Isospora amphiboluri was recorded as the most common parasite of bearded dragons; however, its host specificity was shown to be relatively low, as it was also able to infect veiled chameleons. In addition, other representatives of coccidia, as well as pseudoparasites from prey items, were also recorded. Although the treatment of coccidiosis in reptiles remains debatable, our findings revealed that it was more effective to treat infected animals with anticoccidials than to leave them untreated. CONCLUSIONS: This is a comprehensive study on a variety of genera of gastrointestinal apicomplexan protists in captive reptiles that considers not only their detection and identification based on a robust combination of morphological and molecular data, but also their host specificity, evolutionary relationships, clinical status, and possible pseudoinfections with parasites of prey items that cannot be proven without the use of molecular methods. The study highlights the frequent occurrence and importance of gastrointestinal parasites in the health of captive reptiles, the need for their examination and consideration, and the application of proper management strategies.