Persistence of maternal antibodies against Mycoplasma agassizii in desert tortoise hatchlings

Objective-To investigate Mycoplasma agassizii-specific maternal antibodies in desert tortoise (Gopherus agassizii) hatchlings. Sample Population-Plasma from 43 captive-reared desert tortoise hatchlings. Procedure-ELISA for M agassizii-specific antibodies was performed. Four hat chlings from 4 clutches of 3 M agassizii-seropositive females with chronic upper respiratory tract disease (URTD) were tested on the day of hatching ( set 1), and 20 hatchlings from 4 clutches of 4 M agassizii-seropositive fem ales with URTD and 19 hatchlings from 4 M agassizii-seronegative healthy fe males were tested at 4, 8, 12, and 29 months old (set 2), Immunoblot analys is was performed to determine immunoglobulin classes in yolk and plasma of hatchlings. To determine infection status of hatchlings, yolk, egg shell me mbranes (set 1), and nasal lavage fluid (sets 1 and 2) were examined for M agassizii by use of polymerase chain reaction. Results-Yolk and hatchling plasma had significantly lower amounts of specif ic antibodies than did plasma from adult females. The IgG and IgM antibodie s were transferred, but M agassizii-specific antibodies were of the IgG cla ss. Hatchlings were not infected with mycoplasmas. Offspring of sick female s had significantly higher specific antibody titers than did offspring of h ealthy females. Titers were still significant ly different in 1-year-old ha tchlings. Conclusions-Desert tortoise females transfer specific IgG and IgM antibodie s to their offspring that are still detectable after 1 year, Clinical Relevance-Infection with M agassizii may be misdiagnosed in hatchl ings with persistent maternal antibodies. Passively acquired antibodies may have a role in pathogenesis of mycoplasma-induced respiratory tract diseas e and other diseases.