Monstrous Microbes: Blog 7 Flesh-Eating Crobes/Zombie Ants - Oh MY!
Updated: Jan 9
Halloween is the true turning point of the seasons; Memorial Day and Labor Day can go take a hike! It’s the season of All Hallows' Eve that truly marks the onset of fall and the start of the cold dark end of the year. It’s also, in my opinion, the official start of the holiday season full of delicious food, friends and family. So for this segment of our Macabre Microbial Dungeon, we will talk about food. From monsters that feast on living flesh to ghouls that eat their prey from the inside out, while they're still alive….
Necrotizing Fasciitis - Halloween Horror
We have been talking a lot about Halloween and monstrous microbes over the last couple of blogs. It’s an interesting trait of humans to humanize and personalize everything we cannot explain, even the things we can! We take everything good as a blessing bestowed upon us personally and bad things as a curse of some deserved punishment or plague upon the innocent.
We cannot seem to help ourselves, creating stories of monsters and creatures that prey upon us with malice and cruelty, when in reality, the truth is far more clinical and pragmatic - everything from one-celled organisms to complex multi-system organisms are merely consuming, reproducing, and dying according to their molecular makeup and environment. But surely, there must be some sort of explanation and reason for the terrible things that happen to others - because after all, that reason can be used to rationalize why that horrible thing could never happen to me! What could be more horrible than being eaten alive?!?
Illustration by Noémie Matthey, twitter @NoemieMatthey
You’ve seen the grisly headlines that make you think twice about taking a dip at your local beach: Elderly San Marcos man dies from flesh-eating bacteria after Texas Gulf Coast Fishing trip or Five Connecticut residents infected with flesh-eating bacteria in Long Island Sound. Pretty much all you have to say is flesh-eating and everyone’s skin starts to crawl, surely something evil is at work here! Or is there just a poor misunderstood bacteria doing it’s thing to thrive and survive with no other intent whatsoever. (See, personalization can be done both ways).
There are a number of bacteria that can cause necrotizing fasciitis, including Vibrio vulnificus, which is what we’ll focus on here. This microbe is found in warmer salt or brackish water and is transmitted when it infiltrates via breaks/cuts in the skin including burns, bites, surgical wounds and puncture wounds. Initial symptoms include redness, warmness and swelling of the area which can spread very quickly (sometimes as much as an inch per hour)! The infection is quite painful and will also lead to flu-like symptoms of fever, muscle pain, diarrhea, fatigue, etc.
If left untreated, the infection can kill so much tissue that it leads to treatments becoming ineffective, resulting in the necessity to surgically remove dead tissue to stop the spread of infection.
Since a lot of the damage is under the skin, the diagnosis can be difficult and delays in care can ultimately lead to septic shock and death. So while horrifying to think about one’s flesh being eaten, what’s really going on here from the bacteria’s point of view - is there evil intent trying to disfigure and kill unsuspecting victims?
Like all organisms, Vibrio vulnificus has its own story. It was first recognized as a distinct species in the late 1970s. Virtually every oyster harvested in the USA during summer months harbors this organism. It is a Gram-negative bacterium that’s shaped like a curved rod with a single polar flagellum (a lash-like appendage that protrudes from the cell body, which is used to propel the cell around).
It also has hairlike appendages called pili to help motility and adherence. Iron is important to its growth. Vibrio vulnificus lives in seawater (low to moderate salinity) and enjoys temperatures between 20-30 degrees Celsius (68-86 degrees Fahrenheit). Sounds relatable so far, right? It likes salt water, warm temps, oysters - we could be friends! It’s a plucky little organism, and can go into a dormant state when the temperature is too low, and when it likes the weather a little better, it becomes active again - don’t you wish you could do that?
But here’s where things start to become a little monstrous with Vibrio vulnificus. If it finds its way in via ingestion, the incubation rate is quick and symptoms can arise after 24 hours. It is also tough enough to survive the stomach acid and will enter the bloodstream by penetrating the intestinal wall.
A healthy person will likely experience gastroenteritis (diarrhea and intestinal distress). But, for those with underlying health issues, like liver disease, death can be as quick as 24-72 hours, if left untreated, is more than 50% likely to kill its host. It is often resistant to treatment, so sometimes the infection is fatal even with treatment! Ingestion of Vibrio vulnificus accounts for 95% of seafood related deaths.
It is not fully understood how it does so much damage, but researchers believe it kills lymphocytes in the blood, and that the LPS (lipopolysaccharides) in its cell walls cause the death of cells around it. It also seems to produce an exotoxin that facilitates the release of iron from hemoglobin within the bloodstream. The capsule around it seems to protect it from the body’s defenses, so it is free to multiply and travel throughout the body.
If it gets in via a wound, it can still be deadly, but is more likely to merely cause ghastly injury and illness. It enters the bloodstream via a cut in the skin (the body’s greatest defense against infection). It uses those pili to attach itself to cells and the resulting necrosis (death) of the surrounding cells can result in skin lesions, tissue damage, black spots, pus and flu-like symptoms in its host. Because there are so many types of infections, diagnosis can be delayed and oftentimes the damage to the cells is so severe that antibiotics are not effective enough to stop it, resulting in surgical debridement (removal) of affected tissue and sometimes amputation becomes necessary.
Ok, so it’s maybe difficult to humanize and not demonize Vibrio vulnificus. But the reality is that it is just another organism just trying to enjoy a day swimming in the salt water in the nice warm weather. There are some simple things to do to avoid it (i.e. don’t hide in the graveyard or behind the wall of torture instruments if you’re not looking for a haunting!). Don’t eat raw seafood - boiling/cooking and freezing kills this bacteria - especially if you have any immunocompromising conditions (liver disease, cancer). If you are headed for a swim in salty water, whirlpool, pool or a hot tub, know if you have any breaks in your skin and make sure nothing can get in. Shucking oysters, handling seafood or dealing with tanks or equipment near the ocean? - wear gloves and wash up afterwards - don't be the silly one who walks down the basement stairs after a creepy old door mysteriously creaks open all by itself!
Ophiocordyceps unilateralis - Zombies
Illustration by Mike Hamilton @organizedmike
We all know and love zombies from cinematic adaptations such as “Shaun of the Dead”, “Zombieland” and “28 Days Later” or video games like “Nazi Zombies” in Call Of Duty and “Left 4 Dead”. The truth is, the idea of an undead, brain eating, half decaying corpse, whether limping or charging at you, is a fantasy we’ve all played out once or twice. For me, it’s always been the Shaun of the Dead’s pool scene with Queen blaring in the background that always seemed my speed. At any rate, zombies may be fun Hollywood characters, but to Ants, the concept is oh too real.
Take the compelling story of Annie Ant. Annie was a Camponotus leonardi ant living in a tropical forest. She was out of the canopy nest, picking up leaves, like she did every day. It was a beautiful day and her route was lovely, over limbs with scenic views headed out to get her daily quota of leaves to bring back to the colony. In return, she was given food and shelter and everything she needed to live a productive life.
Suddenly, she spotted an odd shape below her, so she went to investigate. Is that a dead ant? What’s that sticking out of his head? Nah, what would that be doing there? Suddenly a puff of tiny spores is released from a little stem growing out of what appears to be the back of an ant head. Interesting, she thought and moved along. She walked through the smoky cloud, never mind, there’s leaves to fetch, food to eat, sleep to have.
A few days later, Annie left the colony for the last time, but she didn’t know it! Annie started to feel a little strange, muscles twitching and she started to have strange feelings about not getting leaves. No, she thought, I must collect the leaves, I must protect the colony! But her will was not strong enough.
Her path strayed from her route, it felt like someone was controlling her. It seemed to be guiding her to someplace different. Her little legs just kept going until she was on the north side of a plant where the humidity hovered around 94 to 95 percent and the temps between 20-30 degrees celsius.
When she mindlessly climbed about 25 centimeters from the ground she felt compelled to find the underside of a leaf and chomp down on the underside of a leaf on a vein. But wait, she didn’t want to, but her mandibles bit down in a death grip and her world turned to black.
‘I thought she’d never get here’, Cory the Ophiocordyceps unilateralis thought! Sweet! ‘This spot is perfect and I’ve got plenty of food here to start growing and expanding’, he mused as he consumed the ant from the inside. Over the next few days his hyphae spread throughout Annie’s still body.
Yeah baby, I’m feeling a little randy! he thought. A strange antennae-like growth burst through the back of Annie's unthinking head. Just at that moment, another innocent ant, just minding their own business, headed out to get some leaves, saw a strange shape that emitted a puff. Hmm, that’s strange, better get some leaves...
“Zombie Ants”, as they are sometimes referred to, are a product of a parasitic fungus infection, Ophiocordyceps unilateralis. This unique mind controlling fungus is found mostly in Brazil, but can be found throughout tropical environments. Once the fungal spores find its way to the exoskeleton of the ant, they penetrate the body. It proceeds to infiltrate the ants body, secreting mind controlling compounds which eventually leads to host manipulation.
The ants are possessed to leave their home and climb up to an elevated leaf where it clings until it dies. Ophiocordyceps unilateralis then emerges from the corpse usually right behind or through the head. After it punctures from the corpse it’s a must to protect the cadaver from other microbial scavengers. Which means these cordyceps need to live a life that is parasitic (preying on the living), saprophytic (preying on the decaying) and necrotrophic (preying on the dead). Now there’s a Zombie story fit for Hollywood!
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