Zombie blood in 28 Days Later doesn't count

January 5, 2017 6:23 PM

I was joking with a friend about how we should postpone our blood pact because he has a cold, and we realized neither of us really knows if that even makes medical sense. Could you realistically pass on a cold via an ill-timed super-swearsies? Are there any surprising or lesser known "totally can!" or "totally can't!" illnesses in that category? Interesting underlying blood mechanisms?
posted by cortex to Health & Fitness (10 answers total)

I'd be more concerned with Hepatitis C and other actual blood-borne diseases. To be blunt, would you trust swapping bodily fluids with this person in the more customary way?
posted by thelonius at 6:42 PM on January 5, 2017

Hep B and C and HIV are the obvious ones. Then there are microorganisms that might be in the blood such as babesiosis, leptospirosis, arboviral infections (mosquitos and ticks), relapsing fever, Creutzfeldt-Jakob disease, adult T-cell leukemia/lymphoma (caused by HTLV-I), HTLV-I associated myelopathy, diseases associated with HTLV-II, and viral hemorrhagic fever. The vector-borne diseases also involve human blood though usually filtered through an insect.

Realistically? I guess porphyria is along the lines you are thinking.
posted by jessamyn at 6:44 PM on January 5, 2017

Hands are obvious transmitters of the common cold, but in the spirit of your primary question: I'm not saying it's entirely "totally can't!", but the American Public Health Association's Control of Communicable Diseases Manual (which I just happen to have handy) doesn't mention direct blood-to-blood transmittal of the common cold. To whit, the Transmission section states:

Presumably through direct contact or exposure of mucous membranes to respiratory droplets, and indirect transmission through hand and articles freshly soiled by nose and throat discharges of an infected person. Contaminated hands carry rhinovirus, RSV, and probably other similar viruses to the mucous membranes of the eye or nose.

For what it's worth, the incubation period listed is 24 hours to 5 days, with 48 hours being the most common, depending on the agent.
posted by Ufez Jones at 6:51 PM on January 5, 2017

Supplementary: If you want a quick overview of various diseases and isolation procedures/personal protective equipment guidelines, Appendix A of the CDC's Practice Advisory Committee's full document is pretty interesting. The coding is slightly technical, but easily solved via a quick google.
posted by Ufez Jones at 7:08 PM on January 5, 2017

In addition to the usual blood-borne pathogens it's possible for someone to have a blood infection, ie bacteremia, as a complication from another infection such as pneumonia.
posted by pintapicasso at 7:48 PM on January 5, 2017

If you transfer enough blood to each other, you share your antigens. Weird antigen combinations might make it harder to find a match if you need an organ transplant someday.

I'm not sure how much blood it would take to do that, though -- it's somewhere between a simple pinprick and the elevators at the Overlook Hotel.
posted by mochapickle at 7:57 PM on January 5, 2017

A typical cold? Viremia in rhinovirus (and many cold viruses) is not common in adults. That is, not high enough titers in blood to pass on infection. Transmission of cold or flu via transfusion has not been documented (per paper I just skimmed--having issues linking on mobile today, sorry). There was an experiment where viremia was seen during the incubation period of influenza (flu), but that would be before one showed symptoms, not when one is in the mend like your friend. And more importantly, it was pointed out that the inoculation swabs stuck up the noses in that experiment may not reflect the actual viral load one gets from droplets during typical transmission.

So: "slash, slap, & swear" is better than "spit, slap, & swear" if you want to avoid his cold (but don't care about any other blood-borne pathogens you may be exposed to).
Especially with the proper "snort & hork" before the "spit"--cold viral loads will be plenty high in that secretion.
posted by neda at 7:58 PM on January 5, 2017

(For the avoidance of doubt or discomfort I will be clear that the joke was in large part that we had a blood pact to postpone; I don't have any intention of actually sealing any deals with an exchange of bodily fluids. The joke just made me realize that I don't know squat about communicability or not via blood outside of a few fairly well-known examples folks have noted like HIV and hepatitis.)
posted by cortex at 8:09 PM on January 5, 2017

... any surprising or lesser known "totally can!" or "totally can't!" illnesses in that category?

Leprosy.
posted by jamjam at 8:20 PM on January 5, 2017

Nanites.
posted by It's Raining Florence Henderson at 8:04 AM on January 6, 2017