The first three cases of 'super gonorrhea' were recorded earlier this year.

Super gonorrhea doesn't respond to the antibiotics normally used to treat the disease.

Other antibiotic-resistant superbugs are spreading around the world.

A strain of antibiotic-resistant gonorrhea has arrived — the first three cases were recorded between February and April of this year.

Two Australian men and one British man contracted the sexually transmitted infection in Southeast Asia, likely after engaging in unprotected sex, according to the European Center for Disease Control (ECDC). The 'super gonorrhea' strain, a bug called Neisseria gonorrhoeae, is highly difficult to treat given its resistance to the antibiotics that are often used to treat the infection.

Gonorrhea is a bacterial infection that's the second most commonly diagnosed STI in the world. Symptoms include painful urination and abnormal discharge in both women and men, as well as painful or swollen testicles in men and lower abdomen pain and irregular menstruation in women. Some people, however, may carry gonorrhea without showing any symptoms.

There was a total of 468,514 gonorrhea cases in the US alone in 2016, according to the Center for Disease Control.

Gonorrhea is normally treated with one of two commonly used antibiotics: azithromycin or ceftriaxone. Getting treatment for the infection is one of the best ways to prevent the spread of the disease, according to the ECDC. Leaving it untreated, however, can lead to serious complications like pelvic inflammatory disease, infertility, and increased risk of HIV transmission (not to mention the possibility of spreading it to other people).

Mosquitoes containing treatment-resistant antibiotics are on the rise. Thomson Reuters

The infected British man is now undergoing treatment with an experimental drug called ertapenem that's usually used to treat infections after colon and rectal surgery. He reportedly has a girlfriend back home in the UK, but his partner hasn't tested positive for the disease, reports National Geographic.

The super gonorrhea is one of many diseases that's becoming increasingly able to resist traditional antibiotics. In some parts of Southeast Asia, mosquitoes carry a strain of malaria that's becoming more resistant to treatment. And in some cases, superbugs — like MRSA, a type of staph infection — are untreatable, leaving doctors with few options for patients.

Superbugs can also spread their genes to other bacteria as they evolve, according to the CDC. According to some studies, antibiotic-resistant bugs could lead to 10 million deaths by 2050 if doctors and policymakers cannot figure out a way to address the problem.

Fears over drug-resistant infections have led to stricter regulations on feeding antibiotics to livestock and have spurred pharmaceutical companies and doctors to research novel approaches to treatment, though far more work is needed.