Last Sunday, we introduced you to Dr. Peter Cummings, who wrote a fictional book titled The Neuropathology of Zombies. He's a forensic pathologist and we thought it would be interesting to get his opinion on some of our zombie medical questions.

We also asked readers to submit questions and have received some very interesting answers on topics such as zombie digestive tracts, pregnant zombies, the chance of animal infection, and much more:

If zombies digest flesh, how do their digestive tracts work? Would they ever feel full or are they completely insatiable?

In my zombie model the digestive system works by passive diffusion, meaning no metabolic energy is required to absorb (or digest) the food, in this case skin and muscle. Here is a quote from the book that might be a better explanation:

"The digestive system of the Driftwood is dead, it’s not working. To get around this, they eat something that’s already been digested and packaged for transport: blood. I think the blood products may be simply diffusing across the wall of the intestine, without the aid of active transport. Although most of the organ systems are gone, the brain is still marching on. The virus needs certain building blocks to continue to produce it’s DNA, it may be getting these from the blood. These necessary ingredients may simply be diffusing into the body eventually ending up in the brain where they are needed. "

Also, by eating living people, they are getting oxygen from the blood. They might also be getting oxygen that is locked up in muscle as myoglobin.  Oxygen leaves tissue very quickly, and I think that once inside the Driftwood, it’s diffusing through the tissue membranes and getting to the brain. I think we need to study this in more detail.

For zombies that are infected living people, would they be able to sustain themselves solely on human flesh?

That seems to be the case! I haven’t seen zombies at McDonalds! There are some zombies that feed on animals, so I think as long as what they eat is fresh meat, they’d be ok!

In your book, Dr. Hawk is observing zombies from the roof of the hospital, he finds that they do not act aggressive towards each other, and thus can separate fresh flesh and zombie flesh by sense of smell. Which sense is more acute, smell or sight?

I believe it’s by smell. The zombie knows that the dead flesh is rotting and doesn’t contain the necessary nutrients to sustain zombie life. A number of species are attracted to decomposing flesh by smell, blow flies are a good example. Also, maggots only eat dead rotting flesh and to do this they use smell. On a side note, the nose of the maggot is located on it’s rear end. Interesting, huh?

In most cases, a bite from a zombie can infect. In that case, what might be the agent that does the "infecting"?

I think the most commonly used vector is a virus. One real life example of a deadly virus pass via saliva is rabies. In the radiation model there may be a conformational change in a protein that makes it contagious, a real life example being the prion in Mad Cow. Though it’s not caused by radiation, something happens that makes the prion protein contagious. Here is a link to a blog I wrote for the Zombie Research Society about radiation and zombies that explains how this might happen in more detail:

In a real world situation, would it be likely that zombies could infect animal life?

I would think not. If we use the most commonly used vector, the virus, as an example, viruses are typically species-specific. A virus can mutate and then ‘jump species’, which is what we saw with Swine Flu. The zombie virus might not infect both humans and animals, but it may have started as an innocent virus in animals. Having said that, have you seen the movie Dead Meat??

What would be other likely ways that zombie infections would spread? Is an infection going airborne likely?

A virus becoming airborne is bad news. Imagine what would happen if Ebola started to spread like the common cold? A mutation making a virus airborne would be a good way to start serious trouble, as would a virus that mutates and ‘jumps species’. The causative agent might also be passes via food, such as what happens with prions in mad Cow. I think the possibilities are endless, which is what makes the situation so dangerous, it’s impossible to predict. Viral specialists watch a few key viruses around the world that are potential pandemic candidates, but it’s all an educated guess. Scary, I think!

What would happen to a "pregnant" woman who becomes a zombie? Would the fetus become infected?

I think it would depend on the virus. There are several viruses that can cross the placenta and infect the fetus. So I guess a zombie virus could do the same. Check out the re-make of Dawn of the Dead! Zombie babies are freaky.

Some movies show that it is possible for body-parts detached from the main body of the zombie to reanimate and be commanded by the will of the zombie's brain? Is there any medical explanation that would fit this?

I’ve seen some pretty weird things, but I’ve never seen a limb or head move by itself! having said that, given the alteration of the nervous system and the possibility of the virus living in nerves and nerve roots, it is possible that some form of reflex might exist causing the limb to move. For example, when a doctor hits your knee with the little hammer to illicit your reflex, the process is the result of an impulse traveling from your knee to your spinal cord and then back to your knee via stretch receptors and is independent of the brain. It is possible that such a mechanism may remain intact in some zombies.

Is there any medical explanation for why zombies would only be attracted to human flesh?

Yes, for the zombie to maintain its rudimentary metabolism, the building blocks it requires would come from human flesh. There may be something specific in the human flesh that the zombie needs, or more specifically in my model, the virus needs to keep replicating. More importantly, the zombie would need fresh flesh. Decomposing flesh may lack the nutrients necessary to sustain ‘life’.

Do you attribute zombie movement to blood flow. Would blood flow and time of original death attribute to fast moving versus slow moving zombies?

More importantly, I think zombie ‘blood flow’ is dependent on movement. I think the zombie circulation would operate in much the same way as the venous circulation where the muscle movement acts as a pump. This is why you can shoot them in the chest and they don’t die, the heart has become obsolete. As for fast moving zombies, it could have more to do with the cause (virus) and what regions of the brain it’s affecting. Maybe some regions become super-stimulated and create fast moving viruses. Time of death, or really decompositional changes may slow a zombie over time, but I think that the process is so slow (and maybe slowed down by the rudimentary zombie metabolism) that it wouldn’t make that much of a speed difference. Fast zombies are most likely the result of a totally different infectious process.

What's your zombie survival plan? Do you have anything stocked up already in case of a zombie outbreak?

Sadly, I am probably pretty unprepared for the zombie hordes. My wife is the 2012 expert and so she has been carefully getting ready for December 21, 2012. Given my work, if something bad does happen, chances are I’m going to have to be there. Much like in the book, my wife and I have a series of one word codes that mean ‘get out of town’ with varying degrees of severity. We have three places, based on the words, where she is to go and where I hope to meet her and my son. We always have at least 1/2 tank of gas. That’s something people forget about, always keep your tank full!

What are some of your favorite zombie movies?

This is hard. I love Night of the Living Dead. I also really loved the original Dawn of the Dead and also thought the re-make was excellent. Any of the Romero movies are tops with me.

Thank you for taking the time to answer all of these questions for us. Is there anything else you'd like to tell our readers?

I just want to thank everyone who submitted questions and give a big thank you to everyone who read the book. And I want to give a huge thank you to Daily Dead for their support, you guys rock.


To learn more about Dr. Peter Cummings and The Neuropathology of Zombies, visit: