Recognizing that heartworm incidence tends to focus around bodies of water and in warmer parts of the United States, students felt the 1986 heartworm incidence map gave insight into the spread of heartworm, but it just wasn't recent enough knowing Buddy was infected in 2014 and Susie was infected in 2019. So Mrs. Brinza went back to the drawing board searching for more data!
Students broke up into breakout rooms to discuss any patterns they noticed....
And they realized that while this data was helpful, it seemed like there might be more than one cause for both increases and decreases in heartworm incidence. So students were asking for data on other possible causes they were considering. The vote was for temperature data! Students were thinking that a rise in temperature meant more ideal living conditions for mosquitoes, which carry heartworm.
Students were starting to see patterns emerge, but of course, questions arose when the patterns weren't always explainable. For example, why was it that heartworm incidence went down some years even though temperatures were possibly becoming more ideal for mosquitoes to thrive?
And the more we realized from temperature data, is there still another factor that may be playing a role with a fluctuating heartworm incidence from year to year, but an overall upward trend?
Knowing we all agreed to use a cup of water as a dog without "heartworm" at the start, we knew that measuring what value it had before it may have "gotten" heartworm would be important for us in figuring out if a dog got it or not. After everyone analyzed their results, some students were upset that they didn't notice much change, while others witnessed a lot of dogs getting infected! This prompted us to think about why few dogs might get infected while there may be instances where many were infected:
We went back to the model we first developed, claiming that a mosquito could be the instigator of passing the heartworm from dog to dog. We began to see that our data for many situations could continue to support our model:
With all this agreement, we were beginning to wonder how we could figure out what was happening at the time Buddy came to Canine County. Was what transpired over the next four years typical there? What was the area like that Buddy came from?
Mrs. Brinza found that there is actual data collection on heartworm...in fact, it's called heartworm incidence. We looked at a map from 1986--long before Buddy's birth or infection, but it was really interesting to see what this map could tell us!
After testing all the possible items we thought might be able to represent heartworm in our model, we narrowed it down to four: baking soda, vinegar, windex, and soap. Each of these items had a significantly different pH than water. Water was going to represent the dog's blood, and anything of those substances added to water gave a different pH reading. Our thinking would be if a dog ended up with any amount of this substance in its "blood," then it would test positive for heartworm!
Since we are in remote learning now, we thoughtfully took the time to set up our investigation, even naming our dogs. We also had to figure out how each of our dogs would move, and if they would get bitten by a a mosquito or not!
And then it was time...at each of their remote learning locations, students ran the models, seeing what would happen. I am so proud of these kids doing all this on their own...way to go 6th graders! I can't wait to discuss what our models showed us next week!
With our consensus model, we're feeling pretty good about how the heartworm can possibly end up in the dog. But all along we've been curious about how this deadly disease can actually transfer to many dogs...and if it even can! With some vet records, we were able to not only see that other dogs have had the same symptoms as Buddy and Susie, but that they live in the same area as these dogs, too!
We then began thinking about how our models have evolved over time...first it started as a diagram explaining how the heartworm may have ended up in the dog, then how the maps were a useful model to show where and when various dogs got infected. But we still had some skeptical students that aren't fully convinced that our thinking is valid. So we're going to build our own model as a simulation. Students may have gotten some materials from Mrs. Brinza before remote learning started!
Within our breakout rooms, we had LOTS of conversations around what important parts of our model would need to be represented, along with how the model would actually run with supplies we had in our homes that were not provided by Mrs. Brinza. We came to an agreement that all the materials that were provided by Mrs. Brinza could be the dogs and the mosquitoes, and that students would have to supply the "blood" and the "heartworms!" We'd be testing for the heartworm with this special paper we got (pH paper).
We had lots of ideas of what the heartworm could be from our homes (i.e. vinegar, salt, sugar, baking soda, cleaner, etc.). So we figured we should test all these things against just regular blood without heartworm (water). This way we'll figure out which substance will be the most helpful in running our model as we truly figure out how heartworm spreads from dog to dog!
With Susie's results visible, it was hard to wonder what the thin obstruction in her heart was or the foreign protein in her blood. We've always wondered if these symptoms Susie was experiencing were isolated to her, or if other dogs were experiencing the same thing!
We got our hands on some sad results from a dog who unfortunately passed away with the same symptoms as Susie. We spent some time digging deep into the necropsy report!
All this digging deep got us thinking about how the worms could have gotten into the dog in the first place. Check out our models along with our thoughts about them!
We recognized that there were some models that seemed to contradict the results of Buddy's necropsy, so we needed to go back to the drawing board and look at it even deeper! Check out how these groups of students worked to eliminate some of the models we were trying to discuss!
Our discussion over Google Meets felt like a scientist circle...we began really using the necropsy report to rule out various models, including eating or drinking the worms since there was no evidence of the heartworms in the deceased dog's stomach or intestines. We also ruled out worms entering a wound since Buddy had no visible injuries or scars on his body. With some research, we decided to narrow down our thinking into some questions that came up with our remaining possible causes:
1. Inheritance of the disease
2. Worms digging/chewing their way in to the dog's blood.
3. A bug/mosquito
All our conversation eventually led us to consensus...but not without more questions of course!
Our unit is absolutely related to real world phenomena right now: COVID-19 and the effects of climate change. While we are not specifically figuring out COVID-19, we recognize understanding disease transmission is important!