The outbreak of a terrible disease has begun to spread worldwide, and authorities are sounding the alarm. The World Health Organization said in a new report on Friday that drug-resistant gonorrhea is becoming much, much more common, turning what was once a treatable disease into a public health crisis. And now they’re worried we may not be able to stop its rapid spread with present treatments.

Gonorrhea, commonly known as “the clap,” is a common sexually transmitted disease that can pass from just about it any type of sex. The medical community had figured out how to treat it with a dose of antibiotics, but strains are evolving quickly to evade the antibiotics, the WHO says, meaning quick action is needed to stop the disease’s spread.

Penicillin was the original cure for gonorrhea, but the WHO reports that 97 percent of countries report that gonorrhea resists the common treatment ciprofloxacin, 81 percent resist azithromycin, and two-thirds resist even the last-resort drugs.

“The bacteria that cause gonorrhoea are particularly smart. Every time we use a new class of antibiotics to treat the infection, the bacteria evolve to resist them,” said Dr Teodora Wi, Medical Officer, Human Reproduction, at WHO. “These cases may just be the tip of the iceberg, since systems to diagnose and report untreatable infections are lacking in lower-income countries where gonorrhoea is actually more common.”