STD Awareness: The Curious Case of Chancroid

Haemophilus ducreyi arrange themselves in parallel rows, which researchers have called “railroad tracks,” “schools of fish,” and “fingerprints.” Image: Mike Miller, CDC

Earlier this year, I asked a room full of scientists and medical professionals to raise their hands if they’d ever heard of chancroid. Everyone sat there, motionless, confused by the odd syllables I had uttered — shan kroyd. If you’ve never heard of chancroid, you’re not alone.

Chancroid is a sexually transmitted disease (STD) brought to you by Haemophilus ducreyi, a type of bacteria that can pass through microscopic tears in the skin during sexual contact. When one partner is infected, there is a 1 in 3 chance the other will become infected. An infection can cause painful sores and swollen lymph nodes, most often in the genital region. About half of people with chancroid infections will experience “buboes,” or swollen lymph glands that might rupture. Before it could be cured with antibiotics, a persistent infection could cause permanent skin damage.


Humanity can make chancroid the first STD to go extinct.


One reason you probably haven’t heard of chancroid is that, in the developed world at least, it has mostly disappeared. In fact, researchers believe chancroid can be completely wiped off the planet — which would make it the first STD ever to be forced into extinction. How amazing would that be?

Chancroid has been hopping from loin to loin since at least the days of the ancient Greeks, and was common until the 20th century, when rates began to decline. Thanks to antibiotics, U.S. chancroid rates decreased 80-fold between 1947 and 1997, all but vanishing by the late 1950s. It was virtually unheard of until there was another spike in the 1980s, correlating with the crack epidemic. But, since 1987, cases have been steadily declining. Continue reading

STD Awareness: Prevention vs. Punishment

Before antibiotics, syphilis could kill and gonorrhea was responsible for most cases of infertility. Both diseases could spread from husband to wife to baby, potentially destroying families. So you’d think medical breakthroughs in prevention and cures would be welcomed with open arms.

The actual history, like the humans who create it, is much more complicated.


Compassion, rather than fear and guilt, should guide medical practice.


During World War I, sexually transmitted diseases were a huge problem — second only to the 1918 flu pandemic in the number of sick days they caused (7 million, if you’re counting). The Roaring Twenties saw a sexual revolution, and by World War II, the military was once more fretting about losing manpower to debilitating infections that drew men away from the front lines and into the sick bays.

The armed forces did what it could to suppress prostitution and distract soldiers with recreational activities. But the human sex drive could not be contained: The vast majority of U.S. soldiers were having sex — even an estimated half of married soldiers were not faithful to their wives during WWII. Victory depended on soldiers’ health, so during both WWI and WWII, the military provided its sexually active soldiers with “prophylaxis,” medical treatments that could reduce risk for venereal disease — or VD, as sexually transmitted diseases were called back then.

Anyone who thinks condoms are a hassle or “don’t feel good” should read medical historian Allan M. Brandt’s description of a WWI-era prophylactic station, which soldiers were instructed to visit after sexual contact: Continue reading

STD Awareness: Is There a Vaccine for Syphilis?

Before antibiotics, syphilis was the most feared sexually transmitted disease (STD) out there. It was easy to get, quack cures were ineffective and often unpleasant, and it could lead to blindness, disfigurement, dementia, and even death. Syphilis rates were highest during World War II, and plummeted when penicillin became widely available later in the 1940s. By 2000, syphilis rates hit an all-time low, and many scientists thought the United States was at the dawn of the complete elimination of syphilis.

What a difference an antibiotic makes. Image: CDC

Unfortunately, it soon became apparent that syphilis wasn’t ready to go out without a fight. Since 2000, syphilis rates have nearly quadrupled, climbing from 2.1 to 7.5 per 100,000 people by 2015 — the highest they have been since 1994. If you look at the above graph, you might think syphilis rates have been pretty stable over the past 20 years — but if you zoom in, the fact that we’re in the midst of an epidemic becomes more clear.

After hitting an all-time low in 2000, syphilis rates have been increasing nearly every year since.

The epidemic is disproportionately affecting men who have sex with men (MSM), with Arizona seeing a higher-than-average syphilis rate in this group. Additionally, syphilis rates are climbing among women, who have seen a 27 percent bump between 2014 and 2015. And, since women can carry both syphilis and pregnancies, a rise in syphilis in this population also means a rise congenital syphilis (the transmission of syphilis from mother to fetus), which causes miscarriages, stillbirths, preterm births, neonatal death, and birth defects. Ocular syphilis — that is, syphilis infections that spread to the eyes and can lead to blindness — is also on the rise.

Men, women, babies — no one is immune to the grasp of syphilis. Continue reading

STD Awareness: What Does “Congenital Syphilis” Mean?

Treponema pallidum, the bacteria that causes syphilis

Treponema pallidum, the bacteria that causes syphilis

Congenital syphilis, for centuries a leading cause of infant mortality, is often thought of as an antique affliction, relegated to history books — but it is on the rise again. Between 2012 and 2014, there was a spike in congenital syphilis rates, which increased by 38 percent and are now the highest they’ve been in the United States since 2001. As of 2014, the last year for which we have data, more babies were born with syphilis than with HIV.

The word “congenital” simply means that the baby was born with syphilis after being infected in the womb. When an expecting mother has syphilis, the bacteria that cause the disease can cross the placenta to infect the fetus — and will do so 70 percent of the time. As many as 40 percent of babies infected with syphilis during pregnancy will be stillborn or will die soon after birth. It can also cause rashes, bone deformities, severe anemia, jaundice, blindness, and deafness. Congenital syphilis is especially tragic because it’s almost completely preventable, especially when expecting mothers have access to adequate prenatal care and antibiotics. Penicillin is 98 percent effective in preventing congenital syphilis when it is administered at the appropriate time and at the correct dosage.


More babies are being born with syphilis — but this trend can be reversed with wider access to prenatal care.


Incidence of congenital syphilis is growing across all regions of the country, but rates are highest in the South, followed by the West. Rates have also been increasing across ethnic groups, but, compared to white mothers, congenital syphilis rates are more than 10 times higher among African-American mothers and more than 3 times higher among Latina mothers, illustrating the need to increase access to prenatal care for all expecting mothers — and to ensure that this prenatal care is adequate.

Anyone receiving prenatal care should be screened for syphilis at their first visit, and some pregnant people — including those at increased risk or in areas where congenital syphilis rates are high — should be screened a second time at the beginning of the third trimester and again at delivery. Continue reading

STD Awareness: Which STDs Are Resistant to Antibiotics?

You’ve probably heard of MRSA, which is pronounced “mersa” and stands for methicillin-resistant Staphylococcus aureus — a strain of bacteria that is resistant to methicillin, as well as pretty much every other antibiotic out there. MRSA is an example of evolution by natural selection — what didn’t kill its ancestors made them stronger, spawning a drug-resistant strain.


There are drug-resistant strains of gonorrhea, trichomoniasis, and syphilis.


Evolution is the force behind life’s diversity. Normally, diversity is a good thing — but when it comes to microbes that cause diseases like gonorrhea, trichomoniasis, and syphilis, these organisms’ ability to evolve new defenses against our antimicrobial drugs isn’t good for us.

STDs have plagued us for millennia, but it wasn’t until the 20th century that we finally developed antibiotics, which gave us a powerful tool against many of our most formidable sexually transmitted foes. Suddenly, scourges like gonorrhea and syphilis could be quickly and easily treated with a dose of penicillin.

Problem solved, right? Nope. Enter evolution by natural selection. Continue reading

STD Awareness: Genetics and the Gonococcus

Image: CDC

Ever since the discovery of effective antibacterial therapies less than a century ago, humans have been able to easily cure gonorrhea, the sexually transmitted scourge that laid waste to fallopian tubes and robbed newborns of vision. Most of us in the developed world have forgotten that this disease was once a leading cause of infertility in women and blindness in babies — and still is in much of the developing world.

Unfortunately, gonococci — the species of bacteria that cause gonorrhea — have been evolving resistance to every antibiotic we’ve thrown at them, including sulfonamides, penicillins, tetracyclines, macrolides, fluoroquinolones, and narrow-spectrum cephalosporins. We have one remaining first-line gonorrhea treatment left: extended-spectrum cephalosporins, which include cefixime, which is taken orally, and ceftriaxone, which is administered as a shot — and resistance is emerging to those drugs, as well.


Gonococci don’t swap potato salad recipes at family reunions — they swap genetic material!


The emergence of antibiotic-resistant gonorrhea is considered one of the most pressing problems in infectious disease — just two years ago, the Centers for Disease Control and Prevention named it an “urgent threat,” and indeed, gonorrhea seems to be evolving resistance to drugs at quite a rapid clip. Gonococci can acquire resistance to antibiotics in three ways.

First, a genetic mutation can endow bacteria with special antibiotic-fighting powers, making it harder for a drug like penicillin to attach to their cells and destroy them. Such a mutant is more likely to gain evolutionary traction if it finds itself in an antibiotic-drenched environment in which resistance to that drug allows it to “outcompete” other bacteria. Indeed, antibiotic resistance was first documented in the 1940s, just years after sulfonamides and penicillin were introduced as the first effective cures for gonorrhea. Continue reading

STD Awareness: The History of Syphilis

Have you ever heard that syphilis originated in the New World, and was imported to Europe by unwitting explorers? Some say it’s a fitting revenge for Europeans, who brought deadly diseases like smallpox and measles to the Americas. Others say that, while it’s an interesting hypothesis, it’s mostly speculation backed by some intriguing circumstantial evidence.

The predominating theory of syphilis’ origin is that it was transmitted from the Americas to Europe via sailors on Christopher Columbus’ ships — sailors who, in addition to other horrific acts, probably raped the natives of Hispaniola, from whom they could have contracted the infection. Historical records show that syphilis popped up in Europe in the last decade of the 1400s, coinciding with the return of Columbus and his crew — when Europe was deeply mired in war. With war came the far and wide travel of troops, who could have introduced the pathogen to prostitutes and other members of local populations.


In the era before antibiotics, syphilis was the world’s most feared sexually transmitted disease.


But we don’t know for certain that Columbus’ crew brought syphilis back from the West Indies in 1493. Some scholars point to ancient writings, from Biblical texts to Chinese records, that contain descriptions of diseases that are consistent with syphilis — though they might merely have described tuberculosis or leprosy. There are also pre-Columbian skeletons from Europe, Africa, and Asia that seem to exhibit evidence of syphilis infection — though diagnosing syphilis based on bone samples is problematic at best. Is it possible that syphilis had existed in the Old World all along, but didn’t become an epidemic until the wars of the Renaissance era allowed syphilis to conquer the continent?

Or perhaps the New World was home to a mild strain of the disease that mutated once it hit European soil. One team of researchers, studying Guyana’s remote Akwio tribe, discovered a disease that was a lot like syphilis, but was not an STD — it spread by skin-to-skin contact and infected about 1 in 20 children. Genetic analysis showed that it was caused by a bacteria that was closely related to the same bug that causes syphilis. Could Columbus’ men have picked up this transitional strain of bacteria and brought it back to Europe, where it mutated to evolve into the virulent pathogen we know today? Continue reading