Prolonged environmental persistence requires efficient disinfection procedures to control Devriesea agamarum-associated disease in lizards

Abstract

Devriesea agamarum infection causes chronic proliferative dermatitis, especially in desert dwelling lizards. The present study was concerned with evaluating persistency of D. agamarum in the environment and the evaluation of the efficacy of various disinfection procedures. First, the survival of D. agamarum was assessed both in dermal crusts obtained from clinically and naturally infected lizards, and during periods of prolonged nutrient starvation on dry surface, in moist sand and in distilled water. Secondly, a modified European Suspension Test was performed to determine the efficacy of eight procedures for the disinfection of equipment, environmental surfaces and the topical treatment of D. agamarum-associated dermal lesions. The bacterium proved to persist and remain viable for up to 57 days in dermal crusts and for more than 5months in moist sand and distilled water. In contrast, survival on dry surfaces was limited. The results of the described dilution-neutralization method demonstrated that most of the tested disinfection procedures were sufficient in achieving a 5-decimal logarithmic reduction in the number of D. agamarum colony-forming units. The use of relatively low concentrations of hydrogen peroxide and a boric and peracetic acid solution on the other hand resulted in insufficient reduction in viable counts. Devriesea agamarum can persist for long periods of time in the environment, especially under moist conditions, making the use of suitable disinfection procedures necessary. This study demonstrates the need for a dry environment for most desert lizards and the use of effective disinfection procedures next to antimicrobial treatment to eliminate D. agamarum-associated disease from captive saurian collections.