When I worked in a 911 center, we were trained not to transmit unrelated medical information over the radio. If an ambulance is giving a receiving hospital a patient report over radio, they'd give any information relative to the patients condition (vitals, age, LOC, injuries/chief complaint, and ETA). No names ever. That information is part of the transfer of care and is in line with a health professional talking to another health professional about the patient's condition, i.e. protected under federal law. If the disease is not part of the chief complaint, or relative to the nature of the call and responder safety, then it wouldn't be given. However, if serious conditions permitted, the ambulance crew would call the hospital via cell phone to alert them of the patient's medical history. Getting a patient's approval to communicate their medical history will prevent money hungry lawyers from making a case out of a good proactive decision. Make sure it's recorded too.
I've had a patient tell me they had TB AFTER we got to the ER. They were afraid that we wouldn't respond to the call and transport them. Not knowing this, I didn't wear a face shield. Luckily I didn't get anything. I've also found out that bloody trauma patients had HIV days after transporting them, luckily I used gloves. Bottom line, treat every patient cautiously.