cadaver

What's eating you? - Bugs, bacteria, and zombies

laelaps — Thu, 01 Jul 2010 09:08:25 +0000

What's eating you? - Bugs, bacteria, and zombies

The trailer for Shaun of the Dead.

Not all zombies are created equal. The most popular zombie archetype is a shambling, brain-eating member of the recently deceased, but, in recent films from 28 Days Later to Zombieland, the definition of what a zombie is or isn't has become more complicated. Does a zombie have to be a cannibal corpse, or can a zombie be someone infected with a virus which turns them into a blood-crazed, fast-running monster?

For my own part, I have always preferred the classic George Romero zombies from the original Dawn of the Dead and Day of the Dead films (as well as my most favorite of zombie films, Shaun of the Dead). The shuffling, groaning masses not only deliver social commentary in spades - i.e. our transformation into mindless consumers inextricably drawn to shopping malls - but the prospect of slowly being closed in by a seemingly unstoppable horde is far more frightening than any sprinting zombie. Nevertheless, there is one thing that bugs me about zombie movies in the classic vein - where are all the flesh-eating insects?

Zombies are often the star antagonists of horror films, but there is another array of flesh eaters which are usually ignored. For bacteria, flies, and other organisms which typically set to work on cadavers soon after death, a zombocalypse would be a smorgasbord of epic proportions. So, in order to figure out what might happen to the living dead in the days after their horrifying resurrection, I turned to forensic science and taphonomy to see what might worry the zombies themselves.

As outlined by forensic scientist Arpad Vass in a brief overview called "Beyond the grave - understanding human decomposition", it doesn't take long for the human body to break down. Just four minutes after death, oxygen deprived cells begin to digest themselves and spill their contents. This is not visible at first, but after a few days fluid-filled blisters appear on the skin and large parts of the skin begin to slough off. By this time, with the onset of putrefaction and bloating of the corpse, the work of bacteria, fungi, and other microorganisms begins to become apparent.

The characteristic bad odors and greenish skin of zombies are signs of the busy activity of the microorganisms. Slowly but surely, the bacteria and fungi (such as species of Staphylococcus, Candida, Malasseria, Bacillus and Streptococcus) transform tissue into gases and liquids - unless zombies take steps to preserve themselves, their decomposition is inevitable. (Interestingly, in warm, moist environments, zombies would make their own soap through a process called saponification in which fat in the body is transformed under high pH conditions. Cadaver lather, anyone?) Eventually the internal organs will all be broken down leaving the skin as little more than a thin bag around the bones, and soon after that body will become nothing more than a skeleton. Rate of decomposition varies due to temperature and moisture, but, to provide some measure of the speed at which these transformations take place, Vass figured that - at about 50 degrees Fahrenheit - it takes about 128 days for a corpse to be entirely skeletonized.

A time-lapse video of the decomposition of a rabbit. Notice the role that insects play in its decomposition.

But what about insects? Naturalists since the time of Carolus Linnaeus have recognized that these little "death workers", too, play important roles in decomposition, and the more insects tuck into a corpse, the faster it falls apart. Of these, an array of Diptera flies are among the most frequent arthropod visitors to corpses, and their time of arrival has been used to figure out how long a body has been dead. As stated by scientists Carlo Campobasso, Giancarlo Di Vella, and Francesco Introna in their review of flies and decomposition, among the first flies to arrive are species belonging to the Calliphoridae (blow flies), the Sarcophagidae (flesh flies), and the Muscidae (house flies), later followed by members of the Sphaeroceridae (lesser dung flies), Piophilidae (cheese flies), Fanniidae, and Phoridae. They typically lay their eggs around whatever open orifices they can find - especially on the head - with 6 to 10 days between the time they lay their eggs and the time the new adult flies emerge, and the warmer it is, the more species you will find. Beetles do their part, too. Members of the Silphidae (carrion beetles) are early visitors to corpses, while species among the Nitidulidae (sap beetles), Cleridae (checkered beetles), Scarabaeidae (scarabs), and, those most famous of all cadaver beetles, Dermestidae arrive later. (Staphylinidae (rove beetles) and Histeridae (clown beetles) can be found on corpses, too, but these often eat other insects rather than the body itself.)

While zombies would not be quite as easy to prey upon as a stone-still cadaver, I can imagine that at least some of these insects would still try to feed and breed on them, further speeding along decomposition. In fact, unburied bodies often undergo a drastic decline in mass during just a few days, thanks in large part to scavengers, and so it is not unreasonable to speculate that - as much as the living would have reason to fear zombies - bacteria, flies, and even vertebrate scavengers would give zombies something to worry about. As for mammalian and avian scavengers, these animals might be more skittish of zombies than they would be of cadavers, but I have to wonder if some of them might try to take a bite here or there, especially during the time between death and 'zombification' as the putrefaction which soon comes about is more of a deterrent than attractant for everything other than insect scavengers.

Despite horror film scenarios of long-lasting zombie horror, the bodies of the undead would not last very long. Between the natural breakdown of the body following death, the activities of scavengers, the colonization of microorganisms, and the habits of arthropods, any given zombie might only be able to last few a few days, weeks, or months before decomposing so much that they are unable to move. Granted, the beginning of a zombocalypse - when the public remains unaware - would probably be marked by many hapless victims being turned into zombies themselves, but given enough time the epidemic would simply rot itself away. As with H.G. Wells' classic story about alien invasion - War of the Worlds - our greatest assets in confronting the zombie menace would not be guns or chainsaws, but the small organisms which rely on decomposing flesh to make their living.

Campobasso, C. (2001). Factors affecting decomposition and Diptera colonization Forensic Science International, 120 (1-2), 18-27 DOI: 10.1016/S0379-0738(01)00411-X

Carter, D., Yellowlees, D., & Tibbett, M. (2006). Cadaver decomposition in terrestrial ecosystems Naturwissenschaften, 94 (1), 12-24 DOI: 10.1007/s00114-006-0159-1

DeVault, T., Brisbin, Jr., I., & Rhodes, Jr., O. (2004). Factors influencing the acquisition of rodent carrion by vertebrate scavengers and decomposers Canadian Journal of Zoology, 82 (3), 502-509 DOI: 10.1139/Z04-022

laelaps Thu, 07/01/2010 - 05:08

Person or Specimen? Cadavers in the medical dissection lab

bioephemera — Sat, 25 Apr 2009 15:00:00 +0000

Person or Specimen? Cadavers in the medical dissection lab

Christmas greeting card, school unknown, circa 1920.
Dittrick Medical History Center
from Dissection: Photographs of a Rite of Passage in American Medicine 1880-1930

Slate has an intriguing new review by Barron Lerner of a book called Dissection: Photographs of a Rite of Passage in American Medicine 1880-1930, by John Harley Warner and James M. Edmonson. The book delves into the turn-of-the-century practice of photographing medical students with cadavers - photos that today read as weird, grotesque, even offensive.

The photos unearthed by Warner and Edmonson depict an astonishing variety of attitudes toward cadavers. Some of the photos have the earnest, formal air of yearbooks (at least one is of a dissecting club, with the names of the members listed). In others, the cadaver seems to resemble a trophy: you can imagine a similar pose being struck by hunters or fishermen with their kill. Still others use the ancient conceit (which goes back to Vesalius) of depicting skeletons or muscle men as living, moving actors in dynamic poses: in one, the skeleton smokes a pipe with his dissector!

You can see a slideshow of the images here.

Looking at the photos, it's hard to know how one should react. On the one hand, one can dismiss these photos as youthful hijinks, or demonstrations of poor taste. My own experience with dissection students suggests they represent bravado in the face of death - gallows humor intended to mock, and thus defuse, our common mortality. Or perhaps it's the opposite: perhaps our attitudes toward death have changed since the turn of the century, and these medical students simply didn't find cadavers as disquieting as we do today. After all, in our world death typically occurs in a sterile hospital setting and loved ones may never see a lifeless body.

It's impossible to answer these questions without delving into the history of medicine and what exactly "death" means. The cadaver is a complex, socially constructed entity, laden with all kinds of meanings, from the frivolous to tragic to sinister to religious. But in the context of an anatomy lab, it's a specimen whose function is not to symbolize mortality, but to help us learn about the processes that supported life. In a teaching lab, we don't dissect the cadaver to know more about the unique person it used to house, but to understand universal, generic physiological processes. Balancing these different relationships with a cadaver is a challenge for any anatomy novice, and though these issues may have been differently weighted at the turn of the century, I imagine many of them were the same.

The authors of Dissection apparently have similar feelings. From Lerner's review:

Although the photographs may appear inappropriate to us, Warner argues, they commemorate a bonding experience between student and cadaver that was actually lost after 1930. After that point, he says, a new era of objectivity and detachment entered medical education, ending the earlier emotional attachment to the dissection process.(source)

But Lerner seems more concerned with a different issue: the fact that many of the cadavers are African-American, while their dissectors are white. Lerner suggests that might have been a reason why contemporaneous objections to the voyeuristic photos were few.

Warner rightly makes an analogy to the gruesome lynching photographs of the same era that were also distributed to genteel society through various souvenir cards. In a clever bit of historical detective work, Warner and Edmonson even discover that a particular photographer, G.H. Farnum of Oklahoma, actually took both types of photographs. Some of the dissection images contain racist inscriptions, such as "Sliced Nigger," from the Wake Forest School of Medicine and "All Coons Smell Alike to Us," from the College of Physicians and Surgeons of Baltimore. (source)

At this point, the modern reader is sure to recoil. Posing with a skeleton smoking a pipe is one thing, but racist slurs are another issue entirely in our culture, and rightly so.

The question I have, though, is whether African-American cadavers were generally treated much differently by medical students than white cadavers. According to the review, "students at African-American medical schools like Howard also dissected black cadavers and took photographs," so perhaps not. And if there is one thing I've learned about dissection, it's that as one continues, it becomes hard to distinguish gender, much less ethnicity. Dissection strips away the outward differences of age, skin color, socioeconomic class, and nationality, and gets down to the, well, bones of what it means to be human. And while that might just be my optimistic, modern interpretation, I find it hard to imagine that those turn-of-the-century doctors didn't come away from their dissection with an appreciation for how every human being is fundamentally similar. At least I hope so.

Lerner's account of Dissection reminded me of another book I blogged about a couple of years ago: medical resident Christine Montross' Body of Work. Since my post on that book post already expressed many of my feelings about how students relate to cadavers, I decided it might be useful to republish the original post here. So here is what I had to say about Body of Work in 2007. . .

**********************

The LA Times recently reviewed Body of Work: Meditations on Mortality from the Human Anatomy Lab, a memoir by medical resident Christine Montross. I've been trying to decide if I want to read it, and I'm still uncertain. Although a relative novice when it comes to medicine (my degree is in molecular biology), I taught anatomy using human cadavers, and have dissected them. I never found cadavers the least bit disturbing. But I may be unusual in my detachment - my students reacted with disgust, distress, nervousness - and constant anxiety that their reactions weren't normal.

But what is normal? How should we relate to a donated cadaver in the anatomy lab - as a person, or a thing? Some reactions seem to be universal - gallows humor, for example. Humans have been laughing at death since long before Shakespeare. (What other weapon do we have? Death always wins, and the cadaver's the un-living proof of it.) We have some general rules of conduct - for example, treating the cadaver with respect, keeping the pieces of the various cadavers separate, covering face and genitals when they are not being examined. But such rules seem to be mostly for the students' comfort, since it's hard for a cadaver to retain modesty or dignity, at least in a traditional sense, when skin is missing and viscera are exposed.

Students respond to cadavers in personal ways, based on their own family histories, so one student's experience of dissection is unlike any other's. Everyone sees the cadaver differently: is this a person, or a patient, or a body, or a teaching specimen, or an illustration. . .? When students take limbs from a skeleton and hold them up to their own arms, turning them to determine the correct orientation, they enact a little unconscious ritual: memento mori. One student was fine with the cadavers until her grandmother passed away; after that, she found the cadaver so disturbing she couldn't be in the same room with it. The boundaries of life and death, previously comfortably clear, had blurred intolerably. Before class began, students came to me, concerned that they might find the body of a deceased relative in the lab: when and were and who, they wanted to know. (Why came much later.)

Montross' book takes on some of these issues. As reviewed by Harvard professor, poet and doctor Rafael Campo,

"Body of Work" is at its best when Montross, who is also a poet, allows us to observe the astonishing beauty her dissection reveals, and to relish the language she uses to describe it. "The language of these bones slides along their edges," she writes. "Os coxae, the hip bones. Their three parts, with names like flowers: ilium, ischium, pubis.... The pelvic brim, as if water spills over it.... Brim, arch, spine. The ligament names like a call to prayer: sacrospinous, sacrotuberous. Sacrosanct."

This wonder cabinet of anatomical language is familiar to any biologist. It is indeed beautiful. So is the body it describes. But Campo rebukes Montross for allowing such language to establish a clinical distance between herself and the life history of her assigned cadaver, "Eve:"

I believe it is the depersonalization first modeled for aspiring doctors in their encounters with cadavers that accounts for much of the lack of professionalism and career burnout in physicians, and the callous treatment patients too often receive nowadays.

Really: studying the body as beautiful, complex object is a precursor to treating living patients callously? I have never known anyone to leave an anatomy lab feeling less respect and wonder for human beings than before they began. Yet Campo wants the anatomical curriculum to explicitly address the spiritual, not just the physical:

In this age of frequently misapplied technology, here is a chance to make productive use of video cameras and monitors: Might not a video of Eve, telling of her life and created at the time she decided to donate her body, help mitigate some of the mistreatment Montross documents, as well as the subsequent distancing she (however uneasily) comes to approve?

A pleasant idea - and what I'd expect from the author of The Desire To Heal: A Doctor's Education in Empathy, Identity, and Poetry. Empathy should be part of the training of doctors and nurses alike. But is anatomy lab the right venue in which to share the life history of a cadaver? Personal details would increase the discomfort of beginners - in my experience, overly powerful empathy for the deceased disrupts their ability to cut and handle the body (a point Campo seems to dismiss). Would cadavers without life stories receive less respect or care than those who had documented their lives?

Isn't the point that regardless of our living identities, whether we are good or bad, our bodies are kin, after death and in life? When the cadaver was alive, it was home to a unique mind. Now that its cells are dead, is its role in the laboratory to elegize that mind - or to represent universal anatomical mechanisms? As a biologist, the answer seems fairly clear. Perhaps a doctor feels differently; I don't know. But I was disappointed as Montross appears to conclude her book by backtracking from scientific objectivity to elegaic ritual (with Campo's approval):

Great teacher," she intones, "I give you flowers. I carry your body to the funeral pyre. When you burn, may every space in you that I have named flare and burst into light." Thus she aligns herself with the humane tradition of honoring the dead, and the act of love inherent in tending to them. The detached concern she professes to want to emulate seems refreshingly absent here. Perhaps, in recognizing our universal and very human contradictions, there is hope for the beleaguered medical profession, after all.

Honestly, this leaves me cold. I can't speak for anyone else, but if my body ever ends up in a cadaver lab, I don't want people intoning poetry to it. I want them to dissect it. And yes, I said "it," not "me." I'll be dead. My body is a wonderful clockwork, but it ain't me.

The imagined ritual may be beautiful and humane, but it is a pleasant fiction, meant for the observer, not the observed. It has nothing to do with the cadaver's living identity - we have no idea who "Eve" was, nor if she even desired commemoration. Most importantly, the manifest beauty of the human body doesn't require validation by tradition or flowers (or words). We don't have to turn a cadaver into a spiritual symbol to make it a wonder: it already is wonderful, even in death. And if someone fails to understand that, I doubt they should be practicing medicine at all.

***************
Thanks to Mo of Neurophilosophy for the heads-up on the Slate review.

bioephemera Sat, 04/25/2009 - 11:00

Categories

Social Sciences

WOW! What an amazing fucking post, BioE!!

In discussions I have had with my medical students, they have been pretty clear that the levity is a defense mechanism against the horror of death and the grotesqueness of what they are doing to what used to be a human being.

This post reminded me of something I first learned about a good 10 years ago now. There's an awfully long history of photographing corpses. My high school photography teacher had a copy of "Sleeping Beauty: Memorial Photography in America" in the classroom, and it's fascinating looking at what used to be a widely accepted way to memorialize the dead.

Have you ever read Mary Roach's book, Stiff: The Curious Lives of Human Cadavers ?
http://www.maryroach.net/books.html

There's a section discussing a cadaver dissection class at, I believe, Stanford University, and I was impressed by the respect with which these physicians-to-be worked with the cadavers. If I remember correctly, at the end of the semester, when those cadavers had been studied and were now disassembled remains, there was a memorial service to honor the decedents for their generosity.

I kind of like that. I also recall reading somewhere else, and I cannot remember where, that a man intended to leave his body to science specifically because he liked the idea of giving some medical student nightmares.

Gallows humor does not stand up to scrutiny, for the most part, and ought not to be expected to. I remember I had to go to the county coroner's office one time, on an assignment from my supervising attorney, in regard to a body part in the deep freeze. The back office was crowded and on the bulletin boards were all sorts of cartoons and weird things, and in the corner was a skeleton with a bright knit ski cap plopped onto its skull. There's just some stuff you have to do in order to do stuff, you know?

But I don't think I want to look at those photos. Hmmm.

Sarah, for more on memorial photos, Morbid Anatomy has a great set of links here.

First of all, great post. I'm a medical student, just finished my second round of dissection exams, so im especially interested in reading it

One thing I wanted to address, is what you refer to as "levity" or "gallow's humor" by students. In 2 3-week rounds of dissection, working with the other 19 students from my class, I never once noticed such behaviour. Maybe it's the lack of supernatural beliefs in this country, or their attitude towards learning, but all of us were neither mocking or silly nor too stuffy. In other words, we behaved quite normally.

(I'm studying in Prague, by the way)

-Leon

Oh, and by the way, faces and genitals are not covered here. This may be quite important as I think is very reflective of how the human remains are treated differently in these two cases.

I find this rather interesting, in that I wonder how much of this perceived disrespect that Campo is so concerned about actually translates into the development of a healthy and necessary objectivity. Possibly the biggest concern I have about going into clinical work (which even though my focus is going to be research and developing better therapeutic models for treating addiction, will be a big part of my professional life) is becoming better at not internalizing the problems of my future clients. I can see this being a rather big problem for MDs as well and would think that working with cadavers would help.

I am also rather torn about where my remains will be donated. I really like the idea of helping med students, but I am also pretty interested in the body farms and helping further the study of forensic anthropology and crime scene investigations (that and I find an image of my corpse dangling from a tree or half buried rather amusing).

I am definitely not the least interested in letting this body of mine going to waste when I'm done using it.

Hi Jessica:
Thanks so much for your very thoughtful article about our book. As the book's publisher, editor, and designer, I very much appreciate your thoughts and those of the people who have responded as well, and I've passed this along to our authors. I especially like your paragraph about bravado in the face of death. We'll never be able to know precisely what these young men and women thought about, but clearly the range of behavior was broad, from reverential commemoration to breaches of conduct.

I think of this book as one that reveals a fascinating hidden part of American history. By the way, you probably already are familiar with the two MÃ¼tter Museum books we published, in 2002, and 2007, but if not, I feel certain they will interest you as well.

I agree with DuWayne--why let the body go to waste when you've finished with it--or, as is more likely the case, when it is finished with you!

Best wishes,
Laura L

Thanks, Laura - I am very much looking forward to reading the book myself. It sounds like your team did a great job!

For everyone else, note that there is a new review of Dissection today at Inside Higher Ed.

Jessica:

As a whole body donor to a medical school, I believe that a cadaver is a teaching tool, a specimen of a once living person that serves as an anatomical model.

When it comes time for me to become a med school cadaver, hopefully "my" students will thoroughly dissect the remains, while having fun in the process of learning human anatomy. The structure of human anatomy, the product of billions of years of evolution, is, as you say, beautifully complex. Reciting poetry to a cadaver should remain the province of artists and writers, not scientists or doctors in training.

Certainly, I have a different perspective on the topic, in that I once worked in public affairs for a tissue transplant service, recruiting and educating prospective donors and their families for whole body donation. In that capacity, I assisted in several tissue "harvests", as bones, corneas and connective tissue were removed from donors, and transplanted into living recipients. At that time, I also toured anatomy and research labs.

Since I left that position, my Father has had two cornea transplants and cousin has received the donated liver of an accident victim.

Over the years, I've known a number of people who are registered as future body donors, and who donated their bodies for dissection after death. Despite the awkardness associated with the subject of body donation, it is encouraging that more people are considering this option.

Today, whole body tissue banks are increasingly popular, as well as the emerging science of polymer preservation, which a number of medical schools offer to their potential donors.

If the "afterlife" consists of nothing more than serving as a specimen for dissection or transplant tissue, then so be it. Personally, I would consider it an honor to someday join the ranks of other body donors in the gross anatomy lab, and to have my ashes commingled and buried with those of like-minded men and women in a communal cemetary plot, free of religiosity and superstition.

Congratulations on a cogent, excellent web site and blog.

When I die, I want to donate my body. As has been said, I am not exactly using it any more (grin). Further, compliance with my personal religion involves putting it back into the natural cycle; in other words, rotting away to be used up by plants, etc. If I must be embalmed, I'd rather be useful before I'm cremated and buried under a tree.

I am taking a pathophysiology class on-line, and we were given a choice of subjects for our class research paper; I chose plastination. I saw the Body World exhibit while in LA a few years back, and was utterly amazed and transfixed with the whole exhibit and the subject of the plastination process. No longer are burial and cremation our only choices when we die! No one has to be placed in a box, in the ground or on the mantle, wasting space and our opportunity in teaching others about the fasinatic creatures that we are. Donating one's body to medical science and education is an opportunity to give back something of yourself to the world you have left behind. Without the use of cadavers over these many years of medicine's growth, we would still be in the dark ages, brewing snake eyes and frog balls to combat gout or a yeast infection. Call me morbid if you want, but plastination is an art all on its own, and for those that view it as a medium of education, will walk away with a much better understanding of what makes us human, from the inside out. My kids already think me a freak, so seeing me posed with a garden rake in my hand, while showing all the muscles it takes to swing that tool, will certainly be the talk 'round the ole dinner table when someone recounts their visit to see Body Worlds!
PJ, student, granmother, gardener

Just to comment on Patricia's post: Plastination is a groundbreaking technique in anatomical education, and the touring exhibits popularize anatomy to enlighten the general public on the wonders of the human body. I applaud Patricia's decision to be plastinated, and hope that, when the time comes many years from now, she will have the opportunity to spend her "afterlife" as a plastinate, inspiring future generations.

As the daughter of an anatomy professor (Frank H. J. Figge) at the University of Maryland, I used to sit on a stool and watch him demonstrate to students, awed at his dissecting skill. Of course I am donating my body, as he and my mother did. His introduction to Gross Anatomy set the tone of respect, and over the course of two semesters the students learned how wonderfully the human body is made. I hope MY doctors took Gross seriously!

Some years ago a colleague who was an avid fly tying fisherman died. As part of his memorial ceremony, our advisor (we were both DeVore's students) put on display a display box of his flies. One of the flies had been captured and tied up by a spider.