Training While Sick

I am at home right now, contemplating whether or not to go into the dojo tonight. Last night I had a high fever. Though the fever has come down today, I'm still feeling other symptoms. So the question is: how sick is too sick to train? I came up with the following symptom list for determining the answer.

You are too sick to train if you are:
a) Running a fever,
b) Sneezing or coughing excessively,
c) Fatigued and low energy.

The main concern I have when a students come in to train while sick is whether they will spread their illness or whether their lack of energy and focus will cause them to be a danger to themselves or their training partners.

As for myself, I will go in tonight if I'm not running a fever, though I won't train with my students. I'm just going in to oversee the students who are reviewing for their next belt tests.