Day 7: Parasite Eggs!

Today was my first attempt at navigating a college campus, and I didn't even get lost! The morning was spent getting everything ready in the lab so that we could start right away after lunch. We froze the fecal samples over the weekend, and those needed about two hours to thaw, so in the meantime I went to my very first college class, which was Introduction to Equine Science where we learned about the evolution of the horse. I found my way back to Paul's office, ate some lunch, and then started in the lab!

Interestingly, we only found Strongyle eggs in the fecal samples, but it is impossible to determine with a microscope whether they are small or large Strongyles. We started with the five samples that we got from the equine unit, in other words the domestic horses. We got extremely variable results--everything from zero EPG to 1,025 EPG, which is EXTREMELY high. One important thing to note is that some of this variability (especially if the horses are kept in the same conditions) is due to genetics and how strong the horse's immune system is, which is why it is better to test for parasites before treating them to see if the horse really has any. (We used different volumes and amounts than in the video that I watched, so to find the EPG, we had to multiply the number of eggs by 25.) Two out of the five horses that we examined had no eggs, and one of the horses only had one egg, making it an EPG of 25, which is really low. One of the horses had six eggs (EPG of 150), and one had 41 eggs (EPG of 1,025)! There are probably two reasons for this extremely high number: one is genetics, like I said before, and the other is that this horse had an injury and was being kept in a very small pen compared to the large pastures that the other horses had. The feces were not being picked up, and so this horse was eating on top of all of it, which is a perfect situation for a horse to get parasites.

And now for the wild ponies...we really weren't sure what to expect or if we would even find any; I never thought that I would actually get excited at the presence of parasites, but it really is fun when you can find a bunch of eggs. They're really easy to see, too, which makes it more enjoyable. We got 11 samples from the outer banks, which were from several different harems and locations, so it is interesting to compare parasites within different harems, too. Like the domestic horses, there is a LOT of variability in the number of eggs; we got everything from 25 EPG (one egg) to 1,000 EPG (40 eggs).

We got three samples from the first harem we saw, and they were all VERY high--one had 38 eggs, one had 39, and one had 40, which were the highest numbers that we saw in all of the wild pony samples! However, their BCS ranged from a 5-6, which is pretty much perfect. I asked Paul why they would have this many parasites yet still have a good BCS, and he said that one explanation is that the parasites are probably mostly small Strongyles, which don't migrate throughout the body like the large ones do, so they can cause inflammation and irritation in the gut but don't cause as much weight loss as large Strongyles do.

We got four samples from another harem, which were also really high except for one: one had 24 eggs, one had 32, one had 38, but the last one had seven. Because these horses stay together and eat the same things, this lower egg count could be due to genes and how strong the horse's immune system is, but it is hard to say for sure.

The last four samples that we got were all from different harems, and three of them were all pretty low: one had three eggs, one had four eggs, and one only had one egg. The fourth sample had 16 eggs, which is right about in the middle.

I made a lot of progress in terms of my goals today. (By the way, after talking with my on-campus advisor Mr. Boehm, I decided to keep only my first four goals and cut my last three.) In terms of my first goal, I learned the very important skill of how to identify parasite eggs! I had no clue what they looked like before, but now I can pick them out with certainty; I might be doing this in the vet clinic next week, too, but I'm not sure. I also hadn't previously had much experience with a microscope, but I used one for a solid three hours today, which is an extremely important skill to have in the scientific world. In addition, like I said in a previous post, I can use these skills (knowing the process of making the fecal solution, how to pipette it into a slide, how to effectively use a microscope, how to recognize an egg in the solution, and how to analyze the significance of the numbers) to benefit my own animals' health.

I definitely made a lot of progress with my third goal today. Like I said before, I had absolutely no idea what I was going to find in both the domestic and wild horses, but now I have numbers and data to show what the level of internal parasite infestation is.

I also learned a lot about my fourth goal today. I was expecting to find that the horses with a lot of parasites would have a BCS of a three or four, but I was wrong! It turns out that even the animals with very high amounts of parasites can maintain a healthy BCS (of a five or six) depending on the type of parasite and how much damage it does to the horse's system.

Part of my day tomorrow includes making graphs for this data and analyzing it a little further, and the rest of my day will be attending one of Paul's classes (Equine Breeding Farm Management) with a several-hour lab in the afternoon. One of the mares at the equine unit is about to have a foal, and there is a small chance it could happen tomorrow while I'm there. That's something I've never seen but would be really amazing to be able to experience! The chances are pretty low that I'll be there when it happens, though.

Here are a couple of pictures from today; I was also able to take a few pictures of the microscope slides with a special camera, but I don't have them downloaded yet, so be expecting some pictures of Strongyles eggs and graphs in the near future!

Filling a slide with the solution (that's the hardest part!) 

Looking for eggs with Paul looking over my shoulder (Don't worry, Mom...I was wearing gloves almost the whole time!)