# Detection of Viable Nannizziopsis guarroi in Housing Environments Prior to Dermatological Lesion Development in Bearded Dragons (Pogona vitticeps)

## TL;DR

This study shows that the fungus Nannizziopsis guarroi can be found in bearded dragon enclosures before visible skin infections appear, suggesting the environment plays a role in spreading the disease.

## Contribution

The study demonstrates for the first time that viable Nannizziopsis guarroi can be detected in housing environments before clinical signs of infection appear in bearded dragons.

## Key findings

- Viable Nannizziopsis guarroi was detected in 66.67% of enclosures before clinical lesions appeared in bearded dragons.
- The fungus was present in the environment 7–28 days prior to the development of visible dermatomycosis symptoms.
- Environmental seeding of the fungus may occur before clinical signs of infection are observed.

## Abstract

Bearded dragons are a common companion animal and are often infected by Nannizziopsis guarroi, a leading cause of dermatomycosis. In an experimental infection study, viable (culturable) N. guarroi were detected in the environment prior to the development of clinical signs of infection in most bearded dragons. These findings suggest that environment may play a role in disease transmission. Biosecurity measures should be used when handling bearded dragons to limit the spread of this fungus, even if the animal appears to be healthy.

Nannizziopsis guarroi causes dermatomycosis in lizards and snakes. Little is known about the environment’s role in transmission of the fungus. The environments of bearded dragons experimentally inoculated with N. guarroi were cultured weekly to assess the presence of viable N. guarroi. Four of six (4/6, 66.67%) enclosures demonstrated an environmental presence of N. guarroi prior to the observation of clinical lesions in the bearded dragon housed there. The environments were positive for N. guarroi growth 7–28 days prior to lesion development. The environment should be considered as a potential site of infection for naïve reptile hosts and environmental seeding may occur prior to the development of clinical nannizziomycosis in exposed lizards.