I don't know if the problem is between me and Pyomo.DAE or between me and IPOPT. I am doing this all from the command-line interface in Bash on Ubuntu on Windows (WSL). When I run:

JAMPchip@DESKTOP-BOB968S:~/examples/dae$ python3 run_disease.py

I receive the following output:

WARNING: Could not locate the 'ipopt' executable, which is required
  for solver
      ipopt Traceback (most recent call last):   File "run_disease.py", line 15, in 
      results = solver.solve(instance,tee=True)   File "/usr/lib/python3.6/site-packages/pyomo/opt/base/solvers.py", line
  541, in solve
      self.available(exception_flag=True)   File "/usr/lib/python3.6/site-packages/pyomo/opt/solver/shellcmd.py", line
  122, in available
      raise ApplicationError(msg % self.name) pyutilib.common._exceptions.ApplicationError: No executable found for
  solver 'ipopt'

When I run "make test" in the IPOPT build folder, I reecieved:

Testing AMPL Solver Executable...
      Test passed! Testing C++ Example...
      Test passed! Testing C Example...
      Test passed! Testing Fortran Example...
      Test passed!

But my one major concern is that in the "configure" output was the follwing:

checking for COIN-OR package HSL... not given: No package 'coinhsl'
  found

There were also a few warning when I ran "make". I am not at all sure where the issue lies. How do I make python3 find IPOPT, and how do I tell if I have IPOPT on the system for pyomo.dae to find? I am pretty confident that I have "coibhsl" in the HSL folder, so how do I make sure that it is found by IPOPT?
As sascha states, you need to make sure that the directory containing your IPOPT executable (likely the build folder) is in your system PATH. That way, if you were to open a terminal and call ipopt from an arbitrary directory, it would be detected as a valid command. This is distinct from being able to call make test from within the IPOPT build folder.
"No package 'coinhsl' found": IPOPT compiles and passes test, but pyomo cannot find it?