Oral sex is producing dangerous gonorrhea and a decline in condom use is helping it to spread, the World Health Organization says.

It is warning that if you contract gonorrhea, it is now much harder to treat and in some cases impossible.

The sexually transmitted infection is rapidly developing resistance to antibiotics.

Experts said the situation was “fairly grim” with few new drugs on the horizon.

Around 78 million people pick up the STI each year and it can cause infertility.

The World Health Organization analyzed data from 77 countries and it showed gonorrhea’s resistance to antibiotics was widespread.

Dr Teodora Wi, from the WHO, said there had even been three cases – in Japan, France and Spain – where the infection was completely untreatable.

She said: “Gonorrhea is a very smart bug, every time you introduce a new class of antibiotics to treat gonorrhea, the bug becomes resistant.”

Worryingly, the vast majority of gonorrhea infections are in poor countries where resistance is harder to detect.

“These cases may just be the tip of the iceberg,” she added.

Oral sex

Gonorrhea can infect the genitals, rectum and throat, but it is the latter that is most concerning health officials.

Dr Wi said antibiotics could lead to bacteria in the back of the throat, including relatives of gonorrhea, developing resistance.

She said: “When you use antibiotics to treat infections like a normal sore throat, this mixes with the Neisseria species in your throat and this results in resistance.”

Thrusting gonorrhea bacteria into this environment through oral sex can lead to super-gonorrhea.

“In the US, resistance [to an antibiotic] came from men having sex with men because of pharyngeal infection,” she added.

A decline in condom use, which had soared because of fears of HIV/Aids, is thought to help the infection spread.

The infection is spread by unprotected vaginal, oral and anal sex.

Of those infected, about one in 10 heterosexual men and more than three-quarters of women, and gay men, have no easily recognizable symptoms.

But symptoms can include a thick green or yellow discharge from sexual organs, pain when urinating and bleeding between periods.

Untreated infection can lead to infertility, pelvic inflammatory disease and can be passed on to a child during pregnancy. BBC