Detection and Identification of Mycoplasmopsis agassizii in Captive Tortoises with Different Clinical Signs in Italy

Simple Summary Some species of turtle and tortoise are vulnerable or declared threatened and pathogens such as Mycoplasmopsis agassizii can cause severe declines in their populations. Diagnosis and control of transmissible disease is the key for limiting the spread of pathogens in collection of animals. Sequencing and sharing sequences of mycoplasmas obtained from reptiles is important to improve diagnostic tests and to monitor the species affinity and the cross-species transmission potential of mycoplasmas. This study stresses the important role of practitioners in proper collection and sharing of data for appropriate analysis. The results obtained show that M. agasizii is detectable in different specimens and how is important to collect the proper sample to avoid false negative results. Not only animals with upper respiratory diseases should be considered as potentially infected, because M. agassizii sequences were found also in asymptomatic animals and in tortoises with stomatitis without respiratory signs. Coinfection with or infection due to other pathogens should be also considered. Mycoplasmopsis agassizii causes the Upper Respiratory Tract Disease (URTD) in tortoises. The severity of the disease usually ranges from mild to severe respiratory signs. Animals can recover, die, or become asymptomatic carriers and are source of infection for other tortoises. This study describes (i) the clinical history and the results obtained in ten years of diagnostic PCR activity for detecting M. agassizii in different species of captive tortoises in Italy, and (ii) the phylogenetic analysis of the 16S rRNA gene sequences of M. agassizii. A total of 26.0% out of 169 samples resulted positive by PCR and 32 out of 75 (42.7%) animals with symptoms were positive. Sequences ob-tained from the PCR products were conserved, differed from the sequence of the M. agassizii type strain PS6, and were identical to many M. agassizii sequences deposited in databases. In particular, the sequences were identical or very similar to sequences obtained previously from tortoises in It-aly. Since samples collected from different anatomical sites resulted positive, it is suggested that pools of conjunctival, nasal and oral swabs are tested for diagnostic purpose in both symptomatic and asymptomatic animals.

Automated summary

Some species of turtles and tortoises are threatened by pathogens such as Mycoplasmopsis agassizii, which can lead to population declines. Proper diagnosis and control of transmissible diseases are crucial for limiting the spread of pathogens in animal collections. This study highlights the importance of practitioners in collecting and sharing data for analysis and emphasizes the need to collect appropriate samples to avoid false negative results. It also suggests that other pathogens should be considered in coinfection or infection cases.