Tag Archives: parasites

STD Awareness: Trichomoniasis, the Pear-Shaped, Blood-Sucking, Silent Scourge

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What’s shaped like a pear, hangs with a posse of bacteria, and is a silent scourge upon millions of urogenital tracts? I hope you guessed Trichomonas vaginalis, the single-celled parasite that causes trichomoniasis, or trich (pronounced “trick”). Trich is the most common curable sexually transmitted disease out there — currently afflicting around 3.7 million Americans and 156 million Earthlings.

These single-celled creatures pack a punch, but the body fights back.

When trich causes symptoms, sufferers might experience vaginal discharge (which sometimes has a bad odor), penile burning or discharge, spotting, and itching or swelling in the genital area. But around 70 percent of infections have no symptoms at all, making it a mostly “silent” disease. Based on the totality of the evidence, the Centers for Disease Control and Prevention (CDC) doesn’t currently recommend routine screening for trich in people without symptoms.

But it’s the subject of some debate. Since both symptoms and screenings are rare, and the disease isn’t reportable, some health experts worry that trich could be doing a lot of damage right under our noses. An infection during pregnancy could increase risk for preterm labor or low birth weight. It can increase risk for both acquiring and transmitting HIV from or to a partner. Women with trich are more likely to acquire an HIV infection when sexually exposed to the virus — in fact, one study estimated that 6.2 percent of all HIV infections among U.S. women could be attributed to trich. It’s also easier to catch HIV from a man with trich than from a man without trich. Continue reading →

STD Awareness: Drug-Resistant Trichomoniasis

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Two trophozoites of Trichomonas vaginalis, the causative agent of trichomoniasis. Image from the CDC’s Parasite Image Library.

Trichomonas vaginalis organisms, which cause trichomoniasis. Image: Parasite Image Library, CDC

You’ve probably heard of MRSA, which is a strain of Staphylococcus aureus that evolved resistance to all kinds of antibiotics. You also might have heard of other “superbugs,” like Clostridium difficile, aka “C. diff,” or the emerging strains of bacteria that cause antibiotic-resistant gonorrhea. However, other infectious diseases are slowly evolving drug resistance too, but they’re not grabbing headlines. One such disease is trichomoniasis.

We are only starting to learn about drug-resistant trich — and what it means for those who have it.

Trichomonas vaginalis is the single-celled parasite that causes trichomoniasis, or trich (pronounced “trick”). Symptoms can include vaginal discharge (which might have a bad odor), penile burning or discharge, spotting, and itching or swelling in the genital area — but around 70 percent of trich infections are asymptomatic.

Despite its appearance on our list of 10 STDs you’ve probably never heard of, trich is actually the most common curable sexually transmitted disease out there — around 3.7 million Americans are currently infected with trich. When you consider that trich rarely has symptoms, its ubiquity might not even seem all that surprising — there are millions of infections, right under our noses, but mostly unknown and not being aggressively screened for. STD testing doesn’t always include screening for trich, especially in males, who usually don’t have symptoms and can transmit it to others unknowingly. This might not be so bad if trich didn’t cause complications with pregnancy or make it easier to be infected with HIV. Continue reading →

STD Awareness: “Can I Get an STD from Oral Sex?”

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As tools to reduce risk for STD transmission, dental dams are not to be ignored.

Editor’s Note: Other posts of interest to readers include: “Gonorrhea of the Throat,” “Oral Herpes,” “Can Oral Herpes Be Spread to Genitals?,” and “Can Oral Sex Cause Throat Cancer?”

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 diseases (STDs) — 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 diseases 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.

Seventy percent of adolescents who reported engaging in oral sex had never used a barrier to protect themselves from STDs during oral sex.

Some bacterial STDs, 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 STDs 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 →

STD Awareness: Intestinal Parasites

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Editor’s Note: If you’re wondering if there is a sexually transmitted disease (STD) that causes maggots, please see our new article, “Is There an STD That Causes Maggots?”

This colorized scanning electron micrograph shows Giardia lamblia reproducing asexually. Image: Stan Erlandsen, CDC’s Public Health Image Library

Most sexually transmitted diseases 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.

What has eight flagella and can live in your intestines?

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 →

STD Awareness: Trichomoniasis

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Editor’s note: To find out if trichomoniasis can go away on its own, please see our April 2016 post Will STDs Go Away on Their Own?

Trichomonas vaginalis, normally pear-shaped, flattens itself out after attaching to vaginal cells, maximizing surface area between parasite and host. The purple organisms are bacteria. Image: Antonio Pereira-Neves and Marlene Benchimol, Santa Ursula University, Rio de Janeiro, Brazil

Most sexually transmitted diseases are caused by viruses or bacteria. STDs caused by viruses include herpes and genital warts, and the viruses that cause them aren’t even technically living organisms — they are pieces of genetic information that are able to infect a host cell. STDs caused by bacteria include gonorrhea and syphilis; bacteria are microscopic, single-celled organisms with relatively simple cell structures.

But some STDs are caused by other types of living organisms. Protozoan organisms are microscopic and unicellular, like bacteria; unlike bacteria, their cell structures more closely resemble that of the so-called “higher” life forms such as animals and plants. While protozoa are considered to be “animal-like,” they are not animals at all — they are single-celled organisms that reproduce asexually. When certain types of protozoans get into your body, they can cause infections — such as trichomoniasis, the most common curable STD among young females (as well as more females over 40 than previously thought). It is estimated that 7.4 million new cases of trichomoniasis occur annually in the United States; worldwide, there are about 170 million cases each year.

Trichomoniasis, colloquially known as trich, is spread by vaginal or anal intercourse, direct vulva-to-vulva contact, and other activities that involve passing secretions from one partner to another (e.g., sharing sex toys or mutual masturbation). Sexually active people can reduce the risk of contracting trichomoniasis by using latex barriers, such as condoms. Continue reading →