Last year, we shared the fascinating and frightening story of the emergence of increasingly antibiotic-resistant gonorrhea, an STD caused by the gonococci bacteria. The sexually transmitted scourge, which we only so recently reined in with the development of antibiotics, has been performing some genetic gymnastics to defeat almost every drug we’ve thrown at it. We douse it with certain drugs, and the bacterium literally spits them back out at us, and it inactivates other drugs by snapping the active molecules in half. Sulfa drugs, penicillins, tetracyclines, fluoroquinolones — they all make a gonococcus heave a bored sigh. Luckily, cephalosporins were still an effective treatment, but recently there have been reports of stubborn gonorrhea infections caused by the latest and greatest (and some might say most hated) strain of gonococci.
Well, the story isn’t over — just like the bacteria that cause gonorrhea, the tale is rapidly evolving. The latest class of antibiotics that the gonococci are chipping away at is the cephalosporin family, which includes several chemically related drugs that work in similar ways — and that can likewise be defeated by microbes in similar ways. Cephalosporin-resistant gonorrhea was first reported in Japan and documented in a few European countries. The Japanese case that inspired the New England Journal of Medicine to declare last year that it was “time to sound the alarm” was an oral gonorrhea infection that was resistant to one member of the cephalosporin family: ceftriaxone.
Earlier this month, the prestigious medical journal JAMAreported the first North American sightings of gonorrhea that failed treatment with another cephalosporin: cefixime. Yeah, I know, you’d rather hear about Big Foot or UFO sightings, not evidence that something as real and unmythical as Gonorrhea 5.0 has landed in your back yard. Luckily, there’s plenty you can do to protect yourself from it, and we’ll tell you all about it toward the end of this article. (Spoiler alert: It involves using condoms!) Continue reading →
HIV, just like any other virus, is made up of a tiny capsule with a small piece of genetic code inside. While most viruses we’re familiar with store their genes on a molecule called DNA, HIV contains two pieces of RNA, which is another type of gene-storing molecule. The HIV capsules also contain an enzyme called transcriptase, which “translates” the RNA into a strand of DNA that our cells can read. Our cells are then tricked into reading this DNA and producing more copies of the virus — which are then released from the host cell, at which point they are free to infect other cells. In this manner, an HIV infection slowly grows.
When a virus is introduced into a host’s body, immune cells pick it up and carry it to the lymphoid organs — which are a sort of meeting place for other types of immune cells, including CD4+ T helper cells (also called helper T cells). Helper T cells enlist the help of other immune cells, called killer T cells, which destroy cells infected with viruses. Helper T cells also activate the production of antibodies, molecules that are specialized to attach to a specific pathogen so that it can be destroyed. Normally, this is where the virus meets its end. Unfortunately, HIV is different from run-of-the-mill viruses in that it is specialized to invade helper T cells. Now, instead of coordinating an attack against HIV, the helper T cells have been hijacked — converted into factories for the production of yet more HIV. Continue reading →
Our immune systems are beautiful things, refined through millions of years of evolution. The immune system’s complexity is testament to the “arms race” that has been taking place between our species and the harmful pathogens that surround us. Last century, a virus called human immunodeficiency virus (HIV) emerged, and it found a weak spot in our immune system’s armor. HIV has been exploiting this weakness ever since, and an HIV infection can eventually progress to a disease called AIDS, or acquired immune deficiency syndrome. AIDS is a condition that disables our immune system’s ability to function properly, rendering us vulnerable to a host of opportunistic infections and cancers.
HIV is transmitted via bodily fluids: blood, semen, pre-seminal fluid (which can be present without ejaculation), breast milk, vaginal fluids, and rectal mucus. (It can also be present in bodily fluids like amniotic fluid, cerebrospinal fluid, and synovial fluid, to which health-care workers might be exposed.) The virus is not transmitted by fluids like snot, saliva, sweat, tears, and urine — unless blood is present.
Activities that can bring you into contact with HIV-infected bodily fluids include injection drug use and sexual activities like anal, vaginal, or oral sex. It can also be transmitted to a fetus or baby during pregnancy, childbirth, or breastfeeding. In the early days of HIV, many infections occurred as a result of blood transfusions or organ transplants — though nowadays this is a rarity thanks to tissue screening. Lastly, health-care workers might be exposed to HIV through accidents involving needlesticks or cuts. Continue reading →
The above image, with lively yellow splotches against a pale green background, is not a long-lost Jackson Pollack piece, and the dark squiggly lines aren’t strands of paint haphazardly splattered onto a canvas. In 8fact, those squiggly lines are magnified images of the spiral-shaped bacteria species Treponema pallidum. You might not have heard of T. pallidum, but you’ve probably heard of syphilis, the sexually transmitted disease (STD) that these bacteria cause. While syphilis isn’t as common as other STDs, like chlamydia and HPV, it’s still out there, and occasionally communities experience outbreaks. It’s always best for sexually active people to be screened for STDs and practice safer sex.
Syphilis can inflict serious long-term damage — in fact, before the introduction of antibiotics, syphilis was the worst STD out there! Known as the Great Pox when it descended upon Europe 500 years ago, it could cause large and painful boils. Eventually, natural selection led to T. pallidum’s evolution into a form with milder symptoms, which benefited the bacteria by enabling its less boil-ridden (and presumably more attractive) human hosts to spread it farther and wider. Nevertheless, the symptoms of syphilis, if present, still include infectious sores, and when the disease goes untreated, it can cause severe, possibly fatal, damage to the nervous system.
Back in the day, there were myriad inadequate “treatments” for syphilis, ranging from straight-up quackery to the use of partially effective but toxic chemicals such as mercury. But a century ago, in 1912, a new arsenic-based chemical called Neosalvarsan was hailed as a “magic bullet.” Unfortunately, this treatment took weeks or even more than a year to administer — and had dangerous side effects. Quack treatments continued to flourish, and it wasn’t until the widespread adoption of penicillin in the 1940s that an effective cure with few side effects was available.
But natural selection endures; in fact, by flooding T. pallidum’s habitat with certain antibiotics, we’ve created an environment that favors the organism’s evolution against us. While not as immediately threatening as antibiotic-resistant gonorrhea, syphilis has been quietly evolving resistance to some of the antibiotics we use to treat it. This underscores the importance of using antibiotics correctly and emphasizing safer-sex practices, such as using latex condoms during vaginal or anal intercourse and during oral contact with a penis. Continue reading →
Every month since January 2011, we’ve been sharing installments of our STD Awareness series, and each month, we’ve encouraged you to protect yourself from sexually transmitted diseases (STDs) by using dental dams and condoms. But what if you’re trying to get pregnant? In that case, you’re probably not using condoms! However, it is very important that partners know their STD status — being screened and treated for STDs prior to pregnancy is a good idea for your health, and can protect your future baby.
When present during pregnancy, certain STDs can have negative health effects for you or your future baby (including preterm labor, stillbirth, low birth weight, pneumonia, certain infections, blindness, and liver disease), especially if they are not cured or treated in time. Receiving prenatal care can help prevent these problems, so it is important to be screened and treated for STDs prior to or early in your pregnancy.
During pregnancy, the immune system undergoes changes, which are probably necessary to ensure that the body doesn’t reject the fetus — normally, the immune system recognizes non-self cells as potential pathogens and attacks. These immune system changes might make a pregnant person more susceptible to disease. Latent viral infections, like genital warts or herpes, might come out of dormancy. Additionally, anatomical changes lead to a larger exposed area of the cervix, which is potentially more vulnerable to initial infections. Continue reading →
You know what they say: An ounce of prevention is worth a pound of cure. Public health experts agree that vaccines are one of the most important advancements in medicine, and are incredibly safe and effective in preventing infectious disease. Many infectious diseases that used to lay waste to their victims are now unknown to many of us in the developed world — polio, whooping cough, measles, and rabies struck fear in the hearts of our forebears, but most young people today barely know what they are (although low rates of vaccination can still lead to outbreaks, such as 2008’s measles outbreak in Tucson). Smallpox, once a terrifying scourge, has been wiped off the planet thanks to vaccination campaigns.
Vaccines work by introducing antigens to your immune system. An antigen is a substance, such as a protein on the surface of a virus, that the immune system can recognize as dangerous. It is then able to attack the pathogen and, often, create a “memory” of that pathogen so it can attack it in the event of reinfection. The antigens in vaccines are very safe, and can be derived from many sources, such as inactivated (dead) or attenuated (weakened) pathogens, or fragments of pathogens. Some vaccines, such as those protecting against human papillomavirus and hepatitis B, are made with laboratory-synthesized fragments of the surface proteins of viruses, which are sufficient to produce immune response despite being completely noninfectious.
Planned Parenthood Arizona offers vaccinations against hepatitis A, hepatitis B, and human papillomavirus (HPV). All three of these viruses can be transmitted sexually, and hepatitis B and HPV can cause cancer if the infections become chronic. The hepatitis vaccines have led to all-time lows in rates of hepatitis A and hepatitis B; the HPV vaccine is still new, but emerging evidence suggests a possible decrease in HPV rates as herd immunity grows. Vaccination doesn’t just benefit you and your partner(s) — it benefits society as a whole.
In the early 1970s, Ted Slavin, a hemophiliac, learned his blood was special. Over a lifetime of transfusions, he had slowly amassed a huge collection of antibodies, which are proteins produced by the immune system that attach to invaders, such as viruses and bacteria. When he started receiving transfusions in the 1950s, blood wasn’t screened for diseases, which meant that he’d been repeatedly exposed to some pathogens. His immune system manufactured large amounts of protective antibodies to battle these constant invaders, one of which was hepatitis B virus (HBV) — resulting in blood with extremely high concentrations of hepatitis B antibodies.
His physician relayed this discovery to Slavin — most doctors wouldn’t have bothered, and in fact might have surreptitiously sold his blood to researchers. Back then, scientists were at work on a hepatitis B vaccine, and hepatitis B antibodies were a hot commodity. Likewise, Slavin needed money — his medical condition precluded regular work, and treatments were costly. He contracted with labs and pharmaceutical companies to sell his antibodies directly, for as much as $10 per milliliter and up to 500 milliliters per order.
When someone has a chronic HBV infection, the virus has “hijacked” some of his or her cells, “tricking” them into manufacturing copies of the virus. A virus consists of an outer protein shell housing genetic information — the blueprint that cells follow when they produce virus copies. When hepatitis B viruses are manufactured in cells, an excess of surface proteins is produced — these waste products litter the bloodstream, and testing for their presence allows people to be diagnosed with HBV infections. These surface proteins are called antigens — and as luck (or evolution) would have it, the antibodies our immune systems produce can attach to viral antigens, helping us to keep pathogens at bay. Continue reading →
Whether it’s worries over Gardasil making girls go wild, or it’s somber discussion about cervical cancer, discourse about human papillomavirus (HPV) centers around its impact on females. But who are most of these females getting HPV from? For the most part, they’re getting it from male partners. And despite the fact that cervical cancer is the most common cancer associated with HPV, it is not the only one. A high-risk strain of HPV can lead to cancers of the penis, anus, mouth, and throat; additionally, there are strains of HPV that cause genital warts, which affect males and females equally. So why don’t males figure very prominently in discussions of HPV and the preventive vaccine, Gardasil?
Hepatitis isn’t commonly thought of as a sexually transmitted infection (STI) — for most people, hepatitis conjures images of contaminated food or unsanitary restaurants. But hepatitis should be on the radar of anyone who is sexually active. There are several different viruses that cause hepatitis, and some can be sexually transmitted, including hepatitis A (HAV), hepatitis B (HBV), and, to a lesser extent, hepatitis C (HCV).
While HBV is most efficiently transmitted through blood, it can also easily hitch rides from person to person via sexual fluids. However, we covered HBV in depth last year in observance of World Hepatitis Day. As May is Hepatitis Awareness Month, we’ll turn the spotlight on HAV and HCV for this month’s installment of our STI Awareness series.
More than six million Americans are infected with human papillomavirus (HPV) every year, making it one of the most common sexually transmitted infections. There are more than 100 different strains of the virus, some of which can cause genital warts and others of which can lead to cancer. In most cases, an HPV infection will clear up within eight to 13 months, but it can lurk undetected for years, which makes cancer screening very important for anyone who has been sexually active.
Most sexual activities – especially those involving genital-to-genital contact, i.e., vaginal and anal intercourse or simply rubbing genitals together, but also those involving oral and manual contact – can transmit HPV. Although HPV is best known for its connection to cervical cancer in women, it can affect either sex and cause cancers of the vulva, vagina, cervix, penis, anus, oral cavity, or pharynx.
Writing about sexually transmitted infections (STIs), one must walk the line between warning readers of risks and engaging in full-fledged alarmism. So it’s a bit disconcerting that researchers writing in the New England Journal of Medicine last month declared that it’s “time to sound the alarm”: The emergence of completely antibiotic-resistant gonorrhea is becoming more of a realistic threat and less of a theoretical possibility. The bacteria that cause gonorrhea are evolving faster than we can develop effective antibiotics against them, and a return to the era of untreatable gonorrhea could see a rise in the particularly nasty complications that arise from a long-term gonorrheal infection, such as pelvic inflammatory disease and epididymitis.
Neisseria gonorrhoeae is a species of tricky bacteria that cause gonorrhea, which can infect the mouth, throat, rectum, urethra, cervix, and even eyes. These bacteria have vexed us for thousands of years, having evolved many strategies for entrenching themselves in our bodies. They can alter the proteins that adorn their surfaces, rendering our immune systems incapable of recognizing them. They can form colonies in which they work together to manipulate our cell surfaces with their retracting appendages until they’re allowed entry inside, where they can surreptitiously multiply.
You’ve probably heard of MRSA, which is pronounced “mersa” and stands for methicillin-resistant Staphylococcus aureus — a strain of bacteria that has acquired resistance to methicillin, as well as pretty much every other antibiotic to boot. MRSA is an example of evolution by natural selection — what didn’t kill its ancestors made them stronger, spawning a drug-resistant strain.
Why are we talking about MRSA in a post about STIs? It’s not just because MRSA has apparently found a way to be transmitted sexually, but also because it helps make the concept of antibiotic-resistant gonorrhea more accessible. It wasn’t until less than a century ago that we finally developed a magic-bullet treatment for gonorrhea, and for a handful of decades it was quickly and easily treated with a dose of penicillin. Enter evolution by natural selection. Continue reading →
Many consider oral sex to be a safer form of sexual activity compared to vaginal or anal intercourse. For this reason, they might put less emphasis on the use of latex barriers, such as dental dams and condoms, during oral sex. Unfortunately, this idea is misguided and can lead to the transmission of preventable infections.
It is generally true that oral sex presents less of a risk for contracting sexually transmitted infections (STIs) – but this risk is not trivial, especially when people are under the impression that they don’t need to use barrier methods during oral sex. Most sexually transmitted infections can be passed along by oral sex, including chlamydia, gonorrhea, syphilis, hepatitis B, herpes (which can be transmitted back and forth from the mouth, as cold sores, to the genital region, as genital herpes), human papillomavirus (HPV), and HIV. Even pubic lice can be transferred from the genital region to eyelashes and eyebrows! Additionally, intestinal parasites are more likely to be transmitted via oral sex than through vaginal sex. A microscopic amount of fecal matter containing parasites can be infectious, and can be unknowingly ingested when present on genitals.
Some bacterial STIs, such as gonorrhea and syphilis, can do permanent damage if not treated in time. Furthermore, gonorrhea of the throat is much more difficult to treat than gonorrhea in the genital or rectal areas. And some viral STIs can’t be cured (such as herpes and HIV), while others can cause chronic infections that have been linked to cancer (such as hepatitis, which is associated with liver cancer, and HPV, which is associated with throat cancer as well as cervical cancer and anal cancer). Continue reading →
What has eight flagella and can live in your intestines?
Most sexually transmitted infections are caused by bacteria or viruses, but some are caused by organisms that are classified as completely different lifeforms. Trichomoniasis, for example, is caused by a protozoan organism; protozoa occupy their own kingdom, separate from plants, animals, and bacteria. Intestinal parasites are often protozoan organisms, but can also include parasitic worms (which are members of the animal kingdom). They are spread through contact with fecal matter – and as such, they can be transmitted sexually as well as nonsexually. Intestinal parasites are usually transmitted by fecal contamination of food or water, and are most common in areas with insufficient sewage treatment and untreated water in the wilderness. Some pathogens, however, have low infectious doses, making their sexual transmission more likely.
Oral contact with the anus, also called anilingus or rimming, is the primary means of the sexual transmission of these pathogens. Putting fingers or hands in your mouth after they have had contact with the anus is also risky. Other modes of transmission include oral sex, as genitals can be contaminated with feces, as well as sharing sex toys and other equipment. For these reasons, it is very important to use dental dams or latex gloves during contact with the anus; to clean the anus before engaging in rimming; to clean or use condoms on shared sex toys; and to use condoms or dental dams during oral sex. Continue reading →
Most sexually transmitted infections (STIs) are caused by microorganisms – lifeforms that are too small to be seen without a microscope. Many STIs, however, are caused by viruses, which technically aren’t even alive. Rather, viruses are pieces of genetic information that are stored in protein capsules. When these capsules come into contact with a host cell, the genetic information is able to enter the cell and hijack its machinery so that the host cell manufactures copies of the virus, as well as potentially harmful viral proteins. Many well-known STIs, such as herpes and HIV/AIDS, are caused by viruses, but in this article we will focus on two lesser-known viral STIs, cytomegalovirus and molluscum contagiosum.