[5] C. pecorum strains are serologically and pathogenically diverse.

[6] In the koalas, C. pecorum causes infections in the reproductive systems and urinary tract, as well as pneumonia, infertility, and death.

[7] It is considered one of the most important infectious diseases that currently plagues koalas.

[8][9][10] C. pecorum is the most common chlamydial species to infect koalas and is the most pathogenic.

[11] In other animals, C. pecorum has been associated with abortion, conjunctivitis, encephalomyelitis, enteritis, arthritis, and polyarthritis.