This is in the US. Last Wednesday, I woke up feeling under the weather, but it appeared to just be allergies. Regardless, I still took precautions to avoid spreading anything (washing hands, excusing myself to cough, eating separately, warning people to keep a distance, etc). It wasn't until after work I realized I was definitely sick with something that ended up being one of the worst cases of strep I'd ever experienced.
Unfortunately, despite these efforts, a coworker of mine has also gotten sick. While I mostly kept my distance and warned him at the beginning of the day, there was a 10 minute span of time he came over to work at my desk with me seated a bit away. In hindsight, I ought to have reminded him again that I was not doing well and requested, for his sake, I join him at a distance at his desk if necessary. From the wording of his out of office email, it sounds as though it has been a multi-day ordeal, which has me thinking it may have come from me. I understand though, that this is not necessarily true.
While it might be a coincidence, I feel slightly guilty knowing that it could be my fault he is in this situation. In addition, I am worried for his sake, since I know it took me 5 days and antibiotics to even feel well enough to return. I want to communicate these things to him, specifically that I had strep, which needs treatment, rather than the flu, which has similar symptoms. However, I'm unable to figure out a way to do this without sounding overbearing.
I've considered the following response:
I'm sorry to hear you're not doing well. If it is relevant to your situation, you might remember I was out sick last Thursday and Friday. I was diagnosed Thursday with strep throat. Given the proximity of our desks, I feel it's possible I might have unknowingly passed it on to you, and wanted to give you a heads up. If this is the case, I want to apologize. I hope you feel better soon.
My question is, is this an appropriate way to express my concern that his illness may be serious and apologize if I accidentally spread my illness to him?
EDIT: emphasized that I understand that it may just be a fluke. I certainly don't think it's guaranteed, and would like to proceed accordingly.