America’s syphilis epidemic has exploded over the past decade – and doctors now fear the sexually transmitted infection may also be fueling a hidden surge in heart attacks and strokes.
A major new study has found adults diagnosed with syphilis face sharply higher risks of serious cardiovascular problems, which also included dangerous damage to the body’s main artery, the aorta.
Researchers found the risk of death was nearly six times higher among patients with the infection overall.
The warning comes as syphilis cases in the US have ballooned to around 200,000 nationwide – an increase of roughly 80 percent since 2018.
Scientists from Tulane University in New Orleans analyzed medical records from three hospitals covering the years 2011 to 2025.
They identified 1,469 adults diagnosed with syphilis and compared them with more than 7,300 similar patients who had never had the infection.
Both groups had similar ages, rates of diabetes and high blood pressure, and anyone with existing heart disease was excluded from the analysis.
Researchers then tracked patients for an average of six and a half years.
The results alarmed researchers.
Heart attacks occurred in 6.9 percent of syphilis patients compared with 4.2 percent of those without the infection.
Strokes affected 10.3 percent of syphilis patients – compared to just 1.3 percent of controls.
The study also found syphilis patients had a 33 percent higher risk of acute myocardial infarction – the medical term for a heart attack – and a 53 percent higher risk of ischemic stroke, caused by a blocked blood vessel in the brain.
Dangerous swelling or tearing of the aorta – the major blood vessel carrying oxygen-rich blood from the heart to the rest of the body – was also more common among infected patients.
The most severe outcomes were seen in patients with tertiary syphilis, the late-stage form of the disease that can emerge years after the initial infection.
These patients faced a nearly sevenfold higher risk of death and more than five times the risk of aortic complications.
Researchers believe the corkscrew-shaped bacterium that causes syphilis may gradually inflame and damage blood vessels over time, often without obvious symptoms, eventually triggering serious cardiovascular disease.
A new Tulane University study found that syphilis patients had a 33 percent higher risk of acute myocardial infarction, commonly known as a heart attack, compared to similar patients without the infection
Importantly, the study found patients treated during the earlier stages of infection did not appear to face the same increased heart risks – suggesting there may be a critical window before permanent vascular damage develops.
Syphilis has long been considered a disease of the past, associated with the pre-antibiotic era.
The US surge has been driven by declining condom use, drug addiction, cuts to public health funding and reduced access to sexual health services.
Federal data shows the outbreak is hitting some parts of the country far harder than others.
South Dakota recorded the nation’s highest rate of primary and secondary syphilis in 2023, the most recent year on record, with 73.4 cases per 100,000 people.
Washington DC followed at 39.9 cases per 100,000, while New Mexico recorded 36.6 and Mississippi 30.1.
Several Southern states are also reporting alarmingly high infection rates, including Arkansas, Alabama and Louisiana.
Public health experts say multiple factors are driving the surge across the South and Great Plains.
The same Tulane study found that syphilis patients faced a 53 percent higher risk of ischemic stroke, the most common type of stroke, caused by a blocked blood vessel in the brain, compared to matched controls without the infection
Rural healthcare shortages mean many Americans live hours from STD clinics, while small-town hospital closures have further reduced access to testing and treatment.
The methamphetamine and opioid crises are also believed to be accelerating transmission, with drug use linked to riskier sexual behavior and lower rates of healthcare engagement.
Native American communities, which also have a historical mistrust of government health services, have been especially badly affected.
Meanwhile, experts warn stigma surrounding sexually transmitted diseases continues to discourage many people from seeking testing or discussing symptoms openly.
Syphilis is caused by the bacterium Treponema pallidum and is typically spread through sexual contact.
Early symptoms can include painless sores, rashes and swollen glands, though many people may not notice symptoms at all.
If left untreated, the infection can eventually spread throughout the body and attack the brain, nerves, eyes and cardiovascular system.
Doctors say the new findings underline the importance of early testing and rapid treatment with antibiotics before the disease progresses silently into its more dangerous stages.
