Hello, and thanks for writing in.
Different things could be causing these symptoms, such as low blood sugar, a liver disorder, low blood calcium, a neuromuscular disorder called myasthenia gravis, a metabolic disorder (such as Addison's disease), low blood potassium levels. Giving the maple syrup is fine, but I would highly urge you to have your girl examined by a veterinarian and have blood work done as soon as possible to get a diagnosis, so that treatment can be started before the condition worsens.
I hope this helps. Let me know if I can assist further.
Thanks for your reply. A tick-borne disease is possible, and blood tests for these conditions would be needed to confirm that.
Snake bites can do different thing, depending on the type of snake. You can see anything from local swelling and pain, to digestive problems, to respiratory problems, to neurologic symptoms.
Parvovirus symptoms include vomiting, diarrhea, bloody diarrhea, lack of appetite, and lethargy, so this doesn't seem to fit.
I hope this is helpful.