Morbidity and mortality associated with a new mycoplasma species from captive American alligators (Alligator mississippiensis)

Nine of 74 American alligators (Alligator mississippiensis) from a captive Florida herd of 3-4-m-long. 200-350-kg. adult males greater than 30 yr of a ge died within a 10-day period during 1995. Nonspecific clinical signs incl uded anorexia, lethargy, muscle weakness, paraparesis. bilateral white ocul ar discharge. and various degrees of periocular. facial. cervical, and limb edema. Pneumonia. pericarditis, and arthritis were found on postmortem eva luation of the spontaneously dead and euthanatized alligators. Rapidly grow ing mycoplasmas were identified by culture, and mycoplasma nucleotide seque nces were identified by polymerase chain reaction testing of fresh lung and synovial fluid from an affected alligator. Culture of banked frozen lung f rom necropsy specimens and fresh lung and fresh synovial fluid from newly a ffected alligators confirmed the presence of a new mycoplasma species in se ven of eight individuals. Oxytetracycline was administered, but related dea ths continued for 6 mo until only 14 of the initial alligators remained. An enzyme-linked immunosorbent assay to detect antibody was developed, and th e organism was transmitted experimentally to naive juvenile alligators. alt hough the sourer of the organism. Mycoplasma sp. (ATCC 700619). has not bee n identified. The alligator isolate is a novel species in the mycoplasma fa mily because its nucleotide sequence does not match those of over 75 charac terized mycoplasma species. Such factors as population density. animal age, and mycoplasmal virulence likely contributed to the course of disease.