A nurse takes blood from a man who got a free HIV test on a bus in Tehran December 16, 2015. A team of medical experts travelled on a bus to different neighborhoods of Tehran, stationing there for some days to provide education and medical services on the HIV/AIDS disease. They also performed HIV tests on residents. REUTERS/Raheb Homavandi/TIMA ATTENTION EDITORS - THIS IMAGE WAS PROVIDED BY A THIRD PARTY. FOR EDITORIAL USE ONLY. - GF10000267560
FILE - A nurse takes blood from a man who got a free HIV test on a bus in Tehran, Iran, Dec. 16, 2015. The World Health Organization says that more than 1 million people are diagnosed every day with a sexually transmitted disease, which increases their ri

More than 1 million people across the world are diagnosed with sexually transmitted infections (STI) every day, the World Health Organization said.

In a study released Thursday, the U.N. health agency said 1 in every 25 people globally has at least one of four infections: chlamydia, gonorrhea, trichomoniasis and syphilis. Some people have more than one STI, also called sexually transmitted disease.

“These infections indicate people are taking risks with their health, with their sexuality and with their reproductive health,” said Dr. Melanie Taylor, lead author of the report.

The WHO said there were more than 376 million new cases of STIs among men and women aged 15 to 49 in 2016, the latest year for which data is available. The WHO report broke down the infection rates in 2016 to: 127 million new cases of chlamydia, 87 million of gonorrhea, 6 million of syphilis and 156 million of trichomoniasis.

STI’s are transmitted through unprotected vaginal, anal and oral sex. In some cases, the diseases are passed from mother to child during pregnancy. Syphilis can also be transmitted through contact with infected blood.

If left untreated, STIs can cause infertility, stillbirths, ectopic pregnancy and an increased risk of HIV. Syphilis alone causes more than 200,000 newborn deaths and stillbirths each year.

“This is a wake-up call for a concerted effort to ensure everyone, everywhere can access the services they need to prevent and treat these debilitating diseases,” WHO official Dr. Peter Salama said.