From her base in Gallup, New Mexico, Melissa Wyaco supervises about two dozen public health nurses who crisscross the sprawling Navajo Nation searching for patients who have tested positive for or been exposed to a disease once nearly eradicated in the U.S.: syphilis.

Infection rates in this region of the Southwest — the 27,000-square-mile reservation encompasses parts of Arizona, New Mexico, and Utah — are among the nation’s highest. And they’re far worse than anything Wyaco, who is from Zuni Pueblo (about 40 miles south of Gallup) and is the nurse consultant for the Navajo Area Indian Health Service, has seen in her 30-year nursing career.

Syphilis infections nationwide have climbed rapidly in recent years, reaching a 70-year high in 2022, according to the most recent data from the Centers for Disease Control and Prevention. That rise comes amid a shortage of penicillin, the most effective treatment. Simultaneously, congenital syphilis — syphilis passed from a pregnant person to a baby — has similarly spun out of control. Untreated, congenital syphilis can cause bone deformities, severe anemia, jaundice, meningitis, and even death. In 2022, the CDC recorded 231 stillbirths and 51 infant deaths caused by syphilis, out of 3,761 congenital syphilis cases reported that year.

And while infections have risen across the U.S., no demographic has been hit harder than Native Americans. The CDC data released in January shows that the rate of congenital syphilis among American Indians and Alaska Natives was triple the rate for African Americans and nearly 12 times the rate for white babies in 2022.

“This is a disease we thought we were going to eradicate not that long ago, because we have a treatment that works really well,” said Meghan Curry O’Connell, a member of the Cherokee Nation and chief public health officer at the Great Plains Tribal Leaders’ Health Board, who is based in South Dakota.

Instead, the rate of congenital syphilis infections among Native Americans (644.7 cases per 100,000 people in 2022) is now comparable to the rate for the entire U.S. population in 1941 (651.1) — before doctors began using penicillin to cure syphilis. (The rate fell to 6.6 nationally in 1983.)

O’Connell said that’s why the Great Plains Tribal Leaders’ Health Board and tribal leaders from North Dakota, South Dakota, Nebraska, and Iowa have asked federal Health and Human Services Secretary Xavier Becerra to declare a public health emergency in their states. A declaration would expand staffing, funding, and access to contact tracing data across their region.

“Syphilis is deadly to babies. It’s highly infectious, and it causes very severe outcomes,” O’Connell said. “We need to have people doing boots-on-the-ground work” right now.

In 2022, New Mexico reported the highest rate of congenital syphilis among states. Primary and secondary syphilis infections, which are not passed to infants, were highest in South Dakota, which had the second-highest rate of congenital syphilis in 2022. In 2021, the most recent year for which demographic data is available, South Dakota had the second-worst rate nationwide (after the District of Columbia) — and numbers were highest among the state’s large Native population.

In an October news release, the New Mexico Department of Health noted that the state had “reported a 660% increase in cases of congenital syphilis over the past five years.” A year earlier, in 2017, New Mexico reported only one case — but by 2020, that number had risen to 43, then to 76 in 2022.

Starting in 2020, the covid-19 pandemic made things worse. “Public health across the country got almost 95% diverted to doing covid care,” said Jonathan Iralu, the Indian Health Service chief clinical consultant for infectious diseases, who is based at the Gallup Indian Medical Center. “This was a really hard-hit area.”

At one point early in the pandemic, the Navajo Nation reported the highest covid rate in the U.S. Iralu suspects patients with syphilis symptoms may have avoided seeing a doctor for fear of catching covid. That said, he doesn’t think it’s fair to blame the pandemic for the high rates of syphilis, or the high rates of women passing infections to their babies during pregnancy, that continue four years later.

Native Americans are more likely to live in rural areas, far from hospital obstetric units, than any other racial or ethnic group. As a result, many do not receive prenatal care until later in pregnancy, if at all. That often means providers cannot test and treat patients for syphilis before delivery.

In New Mexico, 23% of patients did not receive prenatal care until the fifth month of pregnancy or later, or received fewer than half the appropriate number of visits for the infant’s gestational age in 2023 (the national average is less than 16%).

Inadequate prenatal care is especially risky for Native Americans, who have a greater chance than other ethnic groups of passing on a syphilis infection if they become pregnant. That’s because, among Native communities, syphilis infections are just as common in women as in men. In every other ethnic group, men are at least twice as likely to contract syphilis, largely because men who have sex with men are more susceptible to infection. O’Connell said it’s not clear why women in Native communities are disproportionately affected by syphilis.

“The Navajo Nation is a maternal health desert,” said Amanda Singer, a Diné (Navajo) doula and lactation counselor in Arizona who is also executive director of the Navajo Breastfeeding Coalition/Diné Doula Collective. On some parts of the reservation, patients have to drive more than 100 miles to reach obstetric services. “There’s a really high number of pregnant women who don’t get prenatal care throughout the whole pregnancy.”

She said that’s due not only to a lack of services but also to a mistrust of health care providers who don’t understand Native culture. Some also worry that providers might report patients who use illicit substances during their pregnancies to the police or child welfare. But it’s also because of a shrinking network of facilities: Two of the Navajo area’s labor and delivery wards have closed in the past decade. According to a recent report, more than half of U.S. rural hospitals no longer offer labor and delivery services.

Singer and the other doulas in her network believe New Mexico and Arizona could combat the syphilis epidemic by expanding access to prenatal care in rural Indigenous communities. Singer imagines a system in which midwives, doulas, and lactation counselors are able to travel to families and offer prenatal care “in their own home.”

O’Connell added that data-sharing arrangements between tribes and state, federal, and IHS offices vary widely across the country, but have posed an additional challenge to tackling the epidemic in some Native communities, including her own. Her Tribal Epidemiology Center is fighting to access South Dakota’s state data.

In the Navajo Nation and surrounding area, Iralu said, IHS infectious disease doctors meet with tribal officials every month, and he recommends that all IHS service areas have regular meetings of state, tribal, and IHS providers and public health nurses to ensure every pregnant person in those areas has been tested and treated.

IHS now recommends all patients be tested for syphilis yearly, and tests pregnant patients three times. It also expanded rapid and express testing and started offering DoxyPEP, an antibiotic that transgender women and men who have sex with men can take up to 72 hours after sex and that has been shown to reduce syphilis transmission by 87%. But perhaps the most significant change IHS has made is offering testing and treatment in the field.

Today, the public health nurses Wyaco supervises can test and treat patients for syphilis at home — something she couldn’t do when she was one of them just three years ago.

“Why not bring the penicillin to the patient instead of trying to drag the patient in to the penicillin?” said Iralu.

It’s not a tactic IHS uses for every patient, but it’s been effective in treating those who might pass an infection on to a partner or baby.

Iralu expects to see an expansion in street medicine in urban areas and van outreach in rural areas, in coming years, bringing more testing to communities — as well as an effort to put tests in patients’ hands through vending machines and the mail.

“This is a radical departure from our past,” he said. “But I think that’s the wave of the future.”

This article was produced by KFF Health News, a national newsroom that produces in-depth journalism about health issues and is one of the core operating programs at KFF — the independent source for health policy research, polling, and journalism.