Eaten Alive!

-->Since it’s Halloween, let’s discuss the fact that you are being eaten alive, every second of every day.

It’s common knowledge that the average human body consists of more microorganisms than it does human cells, but no one ever talks about the symbiotic relationship that we’ve developed with each species that inhabits our tissues. Surely, when you think about bacteria and other microbes living on (or in!) you, your first thought is the microbes that live in your guts. But, this symbiotic relationship we’ve developed with other microbes extends much farther than your digestive tract. In fact, your human microbiome covers your entire body, from your skin to your inner digestive tract, in your mouth, on your scalp, everywhere!

Here’s a list of some of the most common human-inhabiting microbes that live amongst your tissues, day in and day out.

1. Demodex folliculorum

Demodex folliculorum is a type of parasitic mite that lives ON YOUR FACE. As we know with other species, mites love to have something on which to cling, so Demodex folliculorum will most likely be found around the hair follicles on your face. If you are thinking “but I wax my entire face!”, here’s a list of where Demodex folliculorum love to live:

• nose hair
• eyebrowns
• eyelashes
• the tiny hair that covers your entire face, but is most commonly on your cheeks and forehead (which my mom used to lovingly call “peach fuzz”).

 

Demodex folliculorum also like to live in your pores. They can be found on other parts of your body, too, but the face region is the most common. Now, don’t hurry to the nearest sink to wash your face. Demodex folliculorum are mostly harmless, and is classified as commensal, which means they benefit from consuming your dead skin and sebaceous gland tissue cells. Since Demodex folliculorum infestation is relatively common, they are considered a part of your normal skin fauna.

 

In the last 10 years or so, dermatologists have theorized that a heavy infestation of Demodex folliculorum may be the cause of rosacea in later years in life. 

2. Spirochaetes spp.

I can’t tell you how many times I’ve heard someone say “…but a dog’s mouth is supposedly really clean!” as a dog licks their face. First off, did you know that dogs consider cat feces a delicacy? Secondly, I’d love to believe that dogs have some secret antimicrobial property that allows them to cure all ailments, but let’s be realistic. We know that magical property only exists in unicorns.

Mouths are pretty disgusting places, regardless of what species you are. For humans with periodontal diseases (such as gingivitis or other oral inflammatory infections), Spirochaetes spp. are levels are elevated. 

 

The Spirochaetes spp. belong to a bacterial phylum that have double membranes (diderm). They are most commonly long coils, and live in those hard-to-reach areas of your mouth. To reproduce, they undergo asexual transverse binary fission, producing two identical cells.

If you have good oral hygiene practices, then you should have nothing to worry about with Spirochaetes spp. They will be found in your mouth no matter what. The only time Spirochaetes spp. can become a problem is if you have periodontal diseases, which can lead to an active infection.

3. Candida albicans

Candida albicans is a common species of yeast that lives in and on your body. You depend on Candida albicans for digestion, as it exists as a part of our normal gut flora.  Yet, sometimes overgrowth can occur, causing candidiasis. 

Candidiasis can rear its ugly head in many anatomical locations. We most commonly hear about yeast infections affecting the female reproductive system, but yeast can inhabit your body in many different areas. 

Yeasts like to live in warm moist areas, so oral tissues are another common location to see a yeast infection. Extreme cases can cause thrush on the tongue. Candidaisis can also occur in your ocular tissues (eyes), and occasionally on the skin. 

I'm keeping this post short because it's my favorite day of the whole year. Halloween is a great time for scientists because we get to put our creative nature into costumes!  If this post wasn't scary enough for you, feel free to check out my post from last Halloween. 

Happy Halloween!

M is for March, and Maggots

I'm sure I don't need to start this by saying I haven't been purposefully neglecting this blog, I really am rather busy. Truly, honestly. But, since I feel so badly about not writing as regularly as I had hoped 3 months ago, I'll make it up by writing about one of my favorite subjects to talk about on a first (and usually last) date.

When you say "fly" to the average person, they usually think about the common house fly, or possibly a unicorn soaring elegantly over a pastel rainbow. Yet, when I think of flies, the first thing that pops into my head is the Botfly. Why? Because its disgusting and amazing.

Botflies are particularly special, because their larvae live as parasites during their development and maturation process. Why would you want to mature in the vast world of exposed nature when you have the opportunity to embed in the flesh of another living species?

Let's break down the amazing lifecycle of the botfly, because its rather unheard of for flies to deposit their eggs anywhere other than...well, you generally only hear of maggots and fly eggs/larvae around garbage cans and dead things, right? These flies are bold, and think that their larvae deserve a better environment than a trashcan. The female botfly, a large and dominating specimen, carries the eggs. She waits until she sees a suitable intermediate vector flying around a suitable host, such as a tick near a grazing animal or a mosquito that is preparing to feast on a human. Once the female botfly has chosen her target, she tackles the insect mid-flight. They begin to fall and roll, and as this happens, the female botfly deposits her eggs onto the intermediate vector and flies away.

I know, this sounds weird, and it definitely is, but the botfly species is smart for doing this. Most species recognize the large botfly as a threat, and will avoid any contact. Yet, if the eggs are disguised on another, much smaller species, then everyone wins!

So now, we've got the intermediate vector covered in eggs. It regains flight and goes after its bloodmeal (although, not all intermediate vectors for the botfly consume blood). When the intermediate vector lands on the mammalian host, the eggs are attracted to the heat, causing them to drop and land on the flesh of their new host. The intermediate vector takes a meal close to the location of the eggs, and they burrow towards the new opening in the flesh.

Once inside, they make their way to a comfortable area under the skin and develop for approximately 8 weeks. They survive subcutaneously by breathing through small tubes in their butt that open at the surface of the skin. These are visible, and will bubble if held underwater.

When the larvae is ready to emerge as a pupae and continue developing in the wild, it will burst from the flesh of it's host. If you can stomach it, here is a video:



Botfly larvae have a distinct "hook" mechanism that allows them to attach to the layers of the skin and avoid being pulled out. If you have a botfly infestation, they must be removed with minor surgery or suffocated before removal. You can see the hooks in these photos, they are clearly visible as the darker spots that form rings around the body.

And here is an awesome photo of a dead (suffocated) botfly larvae being removed from someone's head:

Botflies can be a large issue for small farms raising animals, and for stables holding horses. Also, if the wound is licked, possibly by the animal itself (we've all seen dogs lick their wounds), then the larvae can burrow in the intestinal tract and cause severe infections.

There are many different species of botflies, and they are found all over the world, including in the United States. Now that the weather is going to start warming, you can think of this every time you leave the house!

Happy Spring!