STD Awareness: Three Sexually Transmitted Bugs That Will Fascinate and Intrigue You

From creepy crawly pubic lice, which can be seen with a magnifying glass, to minuscule human papillomaviruses, which can be seen with some of the most expensive microscopes in the world, there are many tiny pathogens that we can acquire through sexual contact. And, despite their diminutive sizes, some of them work in complicated ways, or tell stories about our origins that would blow you away. Let’s learn some amazing facts about three sexually transmitted bugs!

Phthirus pubis, the louse that causes scabies. Image from the Public Health Image Library.

Image: Public Health Image Library

Pubic lice: tiny insects that live in pubic hair

Fans of Charles Darwin might like learning about pubic lice, which offer clues about human evolution. While other apes’ bodies are habitat to only one species of louse, human bodies can host three different types of louse: head lice and the closely related body lice, as well as the distantly related pubic lice.

It is thought that when early humans lost their body hair, human lice followed this receding hairline and migrated to their heads to become head lice. At a later date, the gorilla louse colonized early humans’ pubic regions. Since pubic lice can be transmitted by infested bedding, one idea is that an early human caught pubic lice by sleeping in a burrow that had been recently vacated by a lice-ridden gorilla — no sexual contact required.

By examining the number of differences in the genetic codes of the modern gorilla louse and the human pubic louse, we can place their divergence into two separate species at about 3 million years ago, suggesting that our human ancestors lost their body hair at around that time.

A quite frankly weird fact about pubic lice involves the method their young use to hatch from their eggs — by releasing so much gas that the increase in air pressure causes them to burst from their shell. So there’s that. Continue reading

Does Waxing Get Rid of Crabs?

5266_lores croppedEver since I started writing this blog’s monthly STD Awareness column, I’ve kept my eye out for news related to sexually transmitted diseases. And, while some might find my enthusiasm for STD-related items to be slightly odd, I have been intrigued by what has been splashed across headlines so far this year.

First, in January, the claim surfaced that pubic lice (colloquially known as crabs) are being driven to extinction as their natural habitat is felled by razors and waxes. Then, just last month, a little-known STD called molluscum contagiosum got its 15 minutes when it was associated with the increased popularity of hairless pubic regions.

Some say hair removal is causing a decline of pubic lice; others say it increases virus risk. So what’s the deal?

These headlines might raise some questions: Does waxing or shaving my pubic area decrease my risk of crabs, but increase my risk of molluscum contagiosum? Should I shave or not? The answers to these questions aren’t quite as simple as the headlines make them out to be. Let’s take them one by one.

Does Waxing Prevent Pubic Lice Infestations?

The claim: As reported in the media, pubic lice are disappearing, and the Brazilian wax is the culprit. Articles cite statistics that pubic-hair removal is more popular among young people, and then jump to the conclusion that this trendy hairlessness is spurring a decrease in pubic-lice prevalence.

What the science says: The problem with this claim is that it isn’t backed by solid scientific data — it’s supported by anecdotes from doctors who have noticed a decline in pubic lice among their patients. As the saying goes, though, the plural of anecdote is not data: Without well-designed population studies spanning many years, we can’t actually know if there are fewer pubic lice today than there were before our groins were subjected en masse to depilation techniques. Furthermore, as that other saying goes, correlation does not equal causation: Even if there were a correlation between the Brazilian’s popularity and a decline in public lice, we would need more specialized data to determine if pubic-hair removal actually caused the lowly louse’s depopulation. Continue reading

STD Awareness: Scabies and Pubic Lice

Latex barriers, such as condoms and dental dams, offer fantastic protection against most sexually transmitted diseases (STDs). They are not 100 percent effective, however, and there are even some STDs for which latex poses no obstacle. Because barriers only cover a portion of the genital area, they do not offer sufficient protection against scabies or pubic lice, both of which are caused by infestations of tiny arthropods.

Both scabies and pubic lice are treated with topical medications. A Planned Parenthood health center, as well as other health care providers, clinics, and health departments, can provide testing and treatment. Follow treatment instructions to the letter to ensure success. During this time, you can take actions to prevent reinfection, including vacuuming floors and cleaning rooms, and thoroughly washing all clothing, towels, and bedding in hot water. Your sexual partner(s) might also need to receive treatment.

Now let’s learn more about both specific STDs.


Sarcoptes scabiei, the mite that causes scabies. Image from the Public Health Image Library.

Three-hundred million people carry the eight-legged mite that causes scabies, Sarcoptes scabiei var. hominis. While it’s so small that you need a microscope to see it, it causes an itchy condition that you can definitely feel. The female mite burrows under the skin, usually starting between the fingers and then spreading to the rest of the body, digging until she dies and laying eggs along the way. When the eggs hatch, the nymphs travel to the surface of the skin, where they may transfer to another host or reinfect the original host. Continue reading