Evaluating the Effects of Viruses on Eastern Indigo Snakes (Drymarchon couperi) with Gastric Cryptosporidiosis

Abstract

A breeding colony of wild-origin eastern indigo snakes (EISs, Drymarchon couperi) that is part of a reintroduction program has been impacted by gastric cryptosporidiosis. Gastric cryptosporidiosis is an insidious disease of squamates caused by an apicomplexan protozoan, Cryptosporidium serpentis. Viral coinfections have been implicated as possible immunosuppressant agents that allow for disease progression and both adenovirus and reovirus have been implicated in allowing for the progression of gastric cryptosporidiosis during coinfection in other snake species. Molecular (PCR) screening for adenoviruses and reoviruses was performed for both C. serpentis-positive and C. serpentis-negative EIS within the breeding colony. No reoviruses were detected in the collection. Adenoviruses were present in 11/68 (16.2%) EISs evaluated, and there was no significant difference between C. serpentis-positive and C. serpentis-negative EISs (p = 0.196). There was no significant difference in adenovirus status between C. serpentis-positive EISs' lifespan (p = 0.191) or survival rates (p = 0.823). These findings suggest that the presence of the adenoviruses found in this study does not contribute to the formation or progression of gastric cryptosporidiosis in EISs.

Keywords: Cryptosporidium serpentis; Drymarchon couperi; adenovirus; coinfection; cryptosporidiosis; reovirus.

Figure 1

Bayesian analysis cladogram depicting the relationship of adenoviruses detected in eastern indigo snakes (EISs) to other animal hosts. Adenoviral sequences found in EISs are underlined; other adenoviral sequences first reported in this manuscript are also highlighted (^#). Cladogram branches of viruses detected in toxicoferan hosts are shown in red. Probability values are shown at branch points.