Twenty-Third Annual Meeting and Symposium of the
Desert Tortoise Council, April 3-5, 1998
Abstracts

This study investigated: I. Vertical transmission of Mycoplasma agassizii from mother desert tortoises (Gopherus agassizii) to their hatchlings through the eggs, II. Transfer of specific maternal antibodies, and III. Persistence of maternal antibodies in hatchlings over time. Plasma of 20 captive reared desert tortoise hatchlings from 4 clutches of 4 M. agassizii-seropositive females clinically sick with Upper Respiratory Tract Disease (URTD) and 19 hatchlings from 4 M. agassizii- seronegative clinically healthy females was sampled at 4, 8, 12, and 29 months and examined by ELISA for M. agassizii-specific antibodies. Yolk, egg shell membranes, and nasal lavages tested negative for M. agassizii by polymerase chain reaction (PCR). There was no indication of an active mycoplasma infection in yolks and hatchlings. Offspring of sick females had significantly higher specific antibody levels than offspring of healthy females. The difference between offspring of sick females and offsprings of healthy females was still significant in one year old hatchlings.

It was concluded that M. agassizii was not transmitted through the egg. Desert tortoise females transfer antibodies to their offspring. The transferred specific antibodies were still detectable after one year.

Based on the results of this study, it should be possible to artificially incubate eggs and raise healthy desert tortoises form females infected with M. agassizii to conserve genetic material and restock populations of this threatened species. Transferred specific antibodies can potentially interfere with sero-diagnostic tests, i.e. hatchlings with high antibody levels could potentially be misclassified as having been infected with M. agassizii.