People like to make jokes about gonorrhea.

Maybe it's because this sexually transmitted disease is known as "the clap" (perhaps a reference to the French term "clapier," meaning brothel, or to an early treatment — clapping a heavy object on the man's sexual organ to get discharge to come out).

As the old (and not very funny) joke goes, "If you spread it around, is it called applause?"

But a new study illustrates why this sexually transmitted disease is no laughing matter. Neisseria gonorrhoeae, the bacterium that causes gonorrhea, is developing resistance to the antibiotics that have successfully treated it for decades.

A global group of experts on sexually transmitted diseases published an article in the scientific journal PLOS Medicine outlining the challenges of drug-resistant gonorrhea. They surveyed 77 countries that participate in a global gonorrhea tracking program and found that more than 90 percent report some kind of antibiotic-resistant gonorrhea.

That's bad news for patients. Because while gonorrhea doesn't have the death toll that untreated HIV does — annual deaths from gonorrhea are about 2,300 — it still causes incalculable suffering. About 78 million adults contracted the disease in 2012, according to the World Health Organization. Symptoms include painful urination, itching and a puslike discharge from the penis, vagina or anus, or a sore throat (in throat infections).

Infected people can unwittingly pass it on because not everyone shows symptoms. For women — most of whom never develop symptoms — complications can include infertility and chronic pelvic pain. If pregnant, women with gonorrhea can have premature births or pass the disease to their newborns, who can develop lifelong complications from infection.

Epidemiological studies have shown that gonorrhea and chlamydia infections can also make it easier to become infected with HIV. Researchers don't entirely understand this connection, but they believe the body's immune response to gonorrhea allows HIV to hijack T-cells recruited to fight gonorrhea. Plus, STDs tend to weaken the integrity of genital mucosal linings, an important physical barrier to infections.

"This has been a real hard issue for people to take seriously," said Manica Balasegaram, head of the Global Antibiotic Research and Development Partnership, a joint initiative of WHO and the Drugs for Neglected Diseases Initiative. "It's not seen as a killer disease, but it's a big public health threat."

Unprotected oral sex is one of the main reasons for antibiotic resistance in gonorrhea. Throat infections after oral sex are often mistaken for strep throat or another infection by doctors, who prescribe antibiotics. When gonorrhea in patients' throats is exposed to those drugs, the bacteria develop resistance to them. A person with drug-resistant gonorrhea in the throat can transmit it when performing oral sex on a partner.

Addressing the antibiotic resistance, Thomas Hiltke, a program officer at the National Institute of Allergies and Infectious Diseases Sexually Transmitted Infections Branch, says, "It's at a critical stage. We're at our last class of antibiotics."

Over the past decade, gonorrhea has gradually developed resistance to several antibiotics. In most countries, there is only one class of antibiotics, cephalosporins, that reliably treat all gonorrhea infections. In other parts of the world, the situation is even worse. In Japan, Spain and France, for example, strains of gonorrhea resistant to ceftriaxone — considered the last line of defense against the disease — are cropping up. Doctors have responded by prescribing higher doses or combining antibiotics.

To keep existing drug weapons from being rendered useless, GARDP has allocated $50 million for research and development over the next few years.

A new kind of antibiotic, called zoliflodacin, developed by the private company Entasis, has been shown to be safe and effective in preliminary clinical trials completed in late 2016. The clinical trials were coordinated and funded in part by the U.S. National Institute of Allergies and Infectious Diseases. Larger clinical trials will start in the U.S., South Africa and Thailand in late 2018. The goal is for private-public partnerships that allow private companies to market the drug in richer countries and public health agencies and nonprofits to distribute it in poorer countries that might not be able to afford it.

One way to fight resistant gonorrhea would be to develop fast and cheap lab tests that doctors could use to diagnose antibiotic resistance. If a lab test told doctors within a few hours or less which antibiotics would work on a person's gonorrhea, they could tailor the drug regimen, saving the most powerful antibiotics for the most resistant cases.

Jeffrey Klausner, an epidemiologist at UCLA, is working on a DNA test that will provide those answers.

"It's reasonable to be hopeful," says Klausner. He notes that there have been promising developments for rapid, cheap and portable laboratory tests for infectious diseases in developing countries, including one for HIV.

But testing isn't the solution, he warns. Classic public health strategies like educating people about STD basics — how they spread and using condoms to prevent them — remain important, he says: "A technical approach won't succeed without a strong, well-funded foundation for gonorrhea prevention."

Rina Shaikh-Lesko is a science journalist who writes about medicine, global health and the life sciences. She can be reached@rinawrites

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