Koalas ‘providing insight into STDs’

Australia’s iconic koalas are providing new insights into how sexually transmitted diseases affect fertility in men.


University of Queensland Associate Professor Stephen Johnston says while infections are typically associated with female infertility, new Australian research shows chlamydia interferes with normal embryonic development, damaging male sperm DNA.

“While there has been a lot of work investigating chlamydia in female koalas, studies on the incidence, detection and severity of the organism in male koalas has previously been very limited,” Dr Johnston told AAP.

“We need to understand the incidence of the disease in the wild koala populations, as we think the role of chlamydia in male reproductive disease may have been underestimated.”

Professor Ken Beagley, from QUT Institute of Health and Biomedical Innovation, said there is a poor understanding of how infection affects fertility in men.

“Damage to sperm DNA has certainly been demonstrated in males with chlamydia infections, and a history of chlamydia infections is associated with reduced fertility,” Prof Beagley said.

Chlamydia, a commonly sexually transmitted disease in humans, is a major cause of poor health and death in koalas in South East Queensland and Northern NSW.

Dr Johnston said studying the effects of infection on male fertility was crucial to protecting the native marsupial.

“We have recently found many male koalas are positive for chlamydia, and chlamydia can be isolated from many parts of the male reproductive tract including the testis where sperm is produced,” he said.

“Based on our findings in the koala, we are attempting to develop methods whereby we can either treat the whole animal or the semen sample before natural mating.”