First detection of herpesvirus and prevalence of mycoplasma infection in free-ranging Hermann’s tortoises (Testudo hermanni), and in potential pet vectors
Résumé
Two types of pathogens cause highly contagious upper respiratory tract diseases (URTD) in
Chelonians: testudinid herpesviruses (TeHV) and a mycoplasma (Mycoplasma agassizii). In captivity,
these infections are frequent and can provoke outbreaks. Pet trade generates an international
ow of tortoises, often without sanitary checking; individuals intentionally or accidentally
released in the wild may spread pathogens. A better understanding of the transmission
of infectious agents from captivity to wild tortoises is needed. Many exotic individuals have
been introduced in populations of the endangered western Hermanns tortoise (Testudo hermanni
hermanni), notably spur-thighed tortoises (Testudo graeca). We assessed the presence
of TeHV and mycoplasma in native western Hermanns tortoises and in potential pet vectors
in south-eastern France. Using a large sample (N=572 tortoises), this study revealed, by PCR,
the worrying presence of herpesvirus in 7 free-ranging individuals (3 sub-populations). Additionally,
Mycoplasma agassizii was detected, by PCR, in 15 of the 18 populations sampled
with a frequency ranging from 3.4% (1 of 29 tortoises) to 25% (3 of 12 tortoises). Exotic spurthighed
tortoises showed a high frequency of mycoplasma infection in captivity (18.2%) and
in individuals (50%) found in native Hermanns tortoise sub-populations, suggesting that this
species could be a signicant vector. The paucity of information of TeHV on European tortoise
URTD in natural settings, especially in combination with mycoplasma, prompts further
studies. Indeed, sick tortoises remain concealed and may not be easily detected in the eld.
Our results indicate good health for most infected tortoises but they should be screened in
the eld as well as in captivity.