Chlamydia endangering men’s fertility
CHLAMYDIA, the sexually transmitted infection spreading rapidly among the young, may attack the fertility of men as well as women. New research suggests that far from confining its damaging effects to women, as previously thought, the bacterial infection can damage the DNA of men’s sperm — greatly reducing their chances of fathering a child as a result.
The findings, presented at a conference in Washington this week by Spanish and Mexican researchers, have been greeted with concern by reproductive health experts in Australia, where rates of the largely symptomless infection are soaring among the under-30s. Only last week a new report showed 47,030 notified cases of chlamydia in 2006, a nearly 14 per cent increase on the previous year and a near-doubling on the 24,437 cases reported in 2002.
Women make up the bulk of cases — 27,940 of last year’s 47,030, according to last week’s annual surveillance report issued by the National Centre in HIV Epidemiology and Clinical Research.
However, even these rising rates are thought to be a considerable underestimate, because the lack of symptoms means chlamydia is rarely taken as seriously as other more obvious sexually transmitted infections, and many cases are never picked up.
In women chlamydia can travel to the fallopian tubes, causing a chronic, low-grade inflammation that eventually causes scar tissue to form, blocking the tube irreversibly and preventing eggs from travelling to the uterus. Although the percentage of cases in which this happens is believed to be small, the fact that many tens of thousands of women are infected means the cases of infertility will also be considerable.
In the latest study, researchers led by Jose Luis Fernandez of the Juan Canalejo University Hospital in La Coruna, Mexico, examined sperm taken from 193 men seeking fertility treatment with their partners.
Of these, 143 were found to be infected with both chlamydia and mycoplasma, another common sexually transmitted bacterium, while 50 were uninfected. In the infected group, 35 per cent of the men had sperm with DNA damage, a proportion 3.2 times higher than in the healthy controls.
In the infected group, both partners were then treated with antibiotics. During the early stages of treatment just 12.5 per cent of the couples conceived but, when therapy was complete, 85.7 per cent had achieved a pregnancy.
Fernandez cautioned that his study involved only ‘‘ a small number of couples, so the results are only preliminary’’.
Basil Donovan, professor of sexual health at the National Centre in HIV Epidemiology and Clinical Research, at the University of NSW, says if confirmed by other studies the findings would ‘‘ be very exciting — it would change the whole ball game’’.
‘‘ At the moment in chlamydia control, men are the big blind spot.’’
But if the results are repeated in further studies, he says the ‘‘ whole world should start thinking about screening men’’ for chlamydia infection. Currently this only tends to happen if a couple presents to an IVF clinic seeking help to have a baby.
Associate professor Sarah Robertson, an NHMRC senior research fellow at the Research Centre for Reproductive Health at the University of Adelaide, says the findings are consistent with an emerging evidence that shows sexually transmitted infections generally can damage fertility in men.
Allan Pacey, senior lecturer in andrology at the University of Sheffield and secretary of the British Fertility Society, says that the emerging understanding of how chlamydia affects male fertility should change the way that society approaches the condition.
‘‘ The message is that we might think of chlamydia as a disease that damages female fertility, but we need to think again,’’ he said. ‘‘ It does damage female fertility, but it appears to damage male fertility, too.
‘‘ Previously, it was thought that the most worrying thing about chlamydia infections in men was as a conduit for the infection of women. The thing that drives most men to sexual health clinics is symptoms, and chlamydia is often symptom-free.
‘‘ Chlamydia is getting out of control. We have got to encourage men as well as women to go for screening.’’ Additional reporting: The Times