Sunday, January 11, 2015

The Nivelles Story: My Second Peer-Reviewed Paper Makes JAS

I get it. I kind of dropped the ball for, oh, three months. I can't even guarantee that I'm officially picking it back up again today. Last semester was insanely busy and went by before I could blink. I'm happy to report that other than being crazy it went really well for me. I published a book, got a paper out (for which I was lead author), passed my comprehensive exams, and lined up a ton (technical term) of new projects for the Spring. This semester doesn't look like it will be any slower (which isn't a bad thing), so I will try my best to keep up with posts, but please forgive me if I again drop the ball. (I promise to pick it up again when I get the chance!)

Today, I'm going to talk to you a little bit about my latest publication, which was published this month. This paper was quite a doozy! ("Doozy" is defined by Merriam-Webster as: "something that is unusually good, bad, big, severe, etc."... this paper was unusually good, bad, big, and a whole host of other words.)

My involvement with this paper began long after the analyses were complete. The story begins back in 2011, long before I made my way up to Nebraska. Dr. Karl Reinhard's Archaeoparasitology class began analyzing coproites excavated from skeletonized remains resting in Nivelles, Belgium. The coprolites were many, but hailed from only three individuals. These individuals had lived in this part of Europe during the Medieval period, a time notoriously ridden with filth and disease. As one would expect, these individuals were found to have been hosts to parasitic worms, namely Trichuris trichiura (the human whipworm) and Ascaris lumbricoides (the human mawworm or "giant intestinal roundworm"). European archaeoparasitology is known to yield evidence of such worms in great abundance, especially if you go back in time when our understanding of disease was dominated by miasmatism (the belief that diseases were caused by smells and "bad air" rather that pathogens as we know them to be caused by today).

Finding these individuals to be infected with worms was interesting and important, but it was the infections of a particular individual (from Burial 122) that made this study phenomenal. That individual was an elderly woman. Bone pathology reports tell us that she had no teeth and was suffering from arthritis. The coprolites taken from her remains were abnormally large in size and were much more numerous than would typically be found in such contexts. The coprolites were also backed up beyond her sacral region and into her lumbar region. This indicated that she likely suffered from a bowel obstruction or some other issue that led to constipation. This poor woman probably suffered greatly in her final days.

Examination of her coprolites revealed an abnormal amount of wheat glume in her feces. The fiber rife within her could have contributed to the obstruction, but why would she have been eating it in the first place? And why so much of it? As it turns out, this was a way that Medieval doctors sometimes treated people who were burdened by intestinal worms...and this lady had a major problem with worms.

Figure. 9. Average number of eggs per gram as represented by all three burial sites. 
Gray bars represent Trichuris trichiura while black bars represent Ascaris lumbricoides.
[From Racz et al., 2015]

As you can see from the histogram above, this woman suffered from two different types of worms AND suffered an EXTREMELY heavy infection with whipworms. Keep in mind that the above represents average eggs per gram of feces. That's a LOT of freaking whipworm eggs to find in one person. Let's not forget she also had mawworm eggs alongside those whipworm eggs. Here's a table from the paper that will (or at least should) blow your mind.

[From Racz et al., 2015]

Having so many worms in any one of these coprolite is staggering, but remember that all 8 of these coprolites were inside ONE person! If you add up the "eggs per coprolite" values, you get over 200,000 mawworm eggs and over 1.5 million whipworm eggs...again, all inside of the same person. (Seriously, just let that sink in for a moment.) A whipworm infection this bad has never been reported in anyone. This discovery brings our understanding of Medieval filth and disease to a whole new level. 

Additionally, a female whipworm can only lay about 30K-60K eggs a day (depending on your information source). Though we don't know how long these eggs were sitting inside of this severely constipated woman, we do know that she had to have more than a single worm laying eggs. Having a heavy load of whipworms can cause people to have problems like prolapsed rectum and compromised peristaltic activity of the intestines. (Which translates to: your rectum falls out of your butt and your intestines can't push poo out of you anymore because the muscles aren't working right.) The paper concludes that the extreme parasitism was likely affiliated with the cause of death for this woman.

The paper also discussed the importance of looking at parasite egg taphonomy (how things deteriorate or decay over time) and the co-infection of two worm species as it relates to other aspects of European archaeoparasitology.

I officially joined the Nivelles team as a co-author in my second year, though I had heard all about it in my first semester. You see, the manuscript was pieced together from the term projects of four students and introductory material from colleagues in Europe. The lead author had been working on trying to bring everyone's work together, but it still didn't read like it was written by one person. At the suggestion of my major professor, I worked with the lead author to cut, re-write, and otherwise clean up the manuscript so that it was publishable. This took up much more of my time than I had anticipated, but it was worth it once we finally got it submission-ready. In February, 2014, I took the position of corresponding author and pulled the manuscript through the submission process. We submitted to the Journal of Archaeological Science, and we received excellent reviews. After lots and lots of editing, we finally sent back the final proofs in October, 2014. Our paper was set to be published online in November and in print the following January. That's right, from submitting the first time to print publication was almost a full year. (This doesn't even include the time spent editing prior to submission.)

The Moral of the Story
Despite all the headaches, this was such an amazing project to be a part of, even in the later stages. The author line can boast of researchers spanning four countries on three different continents. It involved an undergraduate, two master's students, two PhD students, and senior researchers from multiple universities. It was a really cool thing to be involved in, and I'm very thankful to have been brought on to help. 

We even got some media attention for the work! Check out the article about it here!

Finally, as might become tradition for parasite papers that I publish, here is a title shot for your viewing pleasure. :)

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