Alex1951 brings up an important subject here, and it will no doubt grow in importance, no matter what kind of weapon one carries (or does not carry, for that matter).
As a security officer, I've received training in "bloodborn pathogens" and other nasty stuff. Along with the much publicized HIV virus, there is Hepatitus C and a few other nasties.
Not to mention sexually transmitted diseases which may be passed on to a victim of rape.
Criminologist Gary Kleck has observed that criminals are generally a very irresponsible group of people who violate not only criminal laws, but also traffic laws and other safety rules, which is why LEOs can often find something other than a traffic violation during a stop. As a result, drug abuse (including intravenous, remember), "safe sex" habits, and for that matter, handwashing, are probably lower in the criminal element than in the general population.
If you are attacked by a scumbag, there is probably a greater chance that your attacker has something you might catch than if you were dealing with a law-abiding person.
For that reason, "exchanging fluids" with a criminal should be discouraged, unless absolutely unavoidable. While we may be envisioning a grappling, slashing, edged weapon melee with a mugger, close range handgun techniques (esp. if you use a contact distance shot) could also result in blood loss and contamination, perhaps with some blood-mingling and/or face splashing.
Also, as an absolute last resort, biting your attacker is certainly acceptable for solving an immediate "death problem," but even if nothing is contracted, waiting for results of HIV tests, etc. will not be pleasant.
There are modern procedures for emergency personnel (LEOs, EMTs) to handle blood on scene, as well as protocols for clean up of the accident/crime area.
I don't think it is prudent to ignore the threat, especially if we can plan on some training or equipment to mitigate it. I wear a pouch with rubber gloves on duty, but I don't carry these off duty. If I ever came into contact with someone else's blood, especially a criminal's (and ESPECIALLY if I had suffered open wounds during an altercation) I would make it a priority to wash off what I could to try to prevent any infections.
I have some ideas on this subject, but I suspect there is a lot more I could learn.
Do you think this topic is better placed in the "Practical/Tactical" section?
Karl
------------------
"Celebrate the diversity of inclusive, self-esteem nurturing, multicultural weapons arts." Karl Spaulding, The Safety Guy