This week was flukes and other wonderful critters that camp out in the liver (and lungs). I was amazed at the similarity of paragonimus lung flukes to moldy pumpkin seeds: they have the exact same ellipsoid shape and off-putting shade of greenish brown. And Fasciola liver flukes are absolutely lovely, they look like those little leaves that accompany the flowers on linden trees. But with intestines.
Best of all were the schistosomes. These are the wormy things behind swimmer's itch, though that's just in people. In dogs they penetrate the skin and go to the liver. They then eventually work their way to the mesenteric veins. where the males and females hook up for a lifelong spooning session. One of our lecturers very kindly provided live specimens in mouse mesentery, so we were able to see the adults in all their, erm, romantic entanglement. Every egg has a little spike on it that helps it move into the lumen of the bowel (and everywhere else). They're pretty immunogenic, so infected animals end up with lots and lots of granulomas wherever the eggs randomly lodge themselves.
We did tissue squash preps with a thoroughly granulomatous liver. My lab partner isn't a great fan of pathology once it's visible with the naked eye, so I had the privilege of setting up the slide. Large chunks of liver with numerous oval eggs: Success! We were advised to keep watching. Sure enough, after a decent amount of time sitting on a warm microscope, a few of the eggs showed signs of life--little larvae starting to squirm around inside. I was fascinated and would have happily waited for them to hatch, but again, my lab partner wanted to finish with the other slides assigned for the day, so I regretfully put the babies aside. When I came back to the slide, all I could find were the immature eggs and empty egg casings--the larvae had hatched and disappeared.
I was a bit disappointed, and scrolled around a bit more in search of a decently mature egg that might be ready to hatch. Then something shot by in the field of view. Rather like being passed by a car doing 80 on the interstate. I hurried after it as best I could (alas, I did not have enough practice with etch-a-sketches for truly proficient microscope driving). More by accident than anything, it darted back into view again--a tiny, bouncing baby schistosome miracidium. It was very cute, in a flubber sort of way. NOT something I want swimming around my internal organs, mind you. It spun around as a blob, then stretched itself out and darted away again. You could tell around the lab who had gotten to the miracidium stage of their squash mount, because it's hard NOT to exclaim when of of these things swims into your field of view and waves.
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