RadioLab has an excellent short episode on one of the most morbidly fascinating of brain infections – rabies.
Rabies is a virus that can very quickly infect the brain. When it does, it causes typical symptoms of encephalitis (brain inflammation) – headache, sore neck, fever, delirium and breathing problems – and it is almost always fatal.
It also has some curious behavioural effects. It can make people hyper-reactive and can lead to uncontrolled muscle spasms due to its effect on the action coordination systems in the brain. With the pain and distress, some people can become aggressive.
This is known as the ‘furious’ stage and when we describe some as ‘rabid with anger’ it is a metaphor drawn from exactly this.
Rabies can also cause what is misleadingly called ‘hydrophobia’ or fear of water. You can see this in various videos that have been uploaded to YouTube that show rabies-infected patients trying to swallow and reacting quite badly.
But rabies doesn’t actually instil a fear of water in the infected person but instead causes dysphagia – difficulty with swallowing – due to the same disruption to the brain’s action control systems.
We tend to take swallowing for granted but it is actually one of our most complex actions and requires about 50 muscles to complete successfully.
Problems swallowing are not uncommon after brain injury (particularly after stroke) and speech and language therapists can spend a lot of their time on neurorehabilitation wards training people to reuse and re-coordinate their swallow to stop them choking on food.
As we know from waterboarding, choking can induce panic, and it’s not so much that rabies creates a fear of water, but a difficulty swallowing and hence experiences of choking. This makes the person want to avoid trying to swallow liquids.
Bathing, for example, wouldn’t trigger this aversion and that’s why rabies doesn’t really cause a ‘fear of water’ but more a ‘fear of choking on liquids due to impaired swallowing’.
The RadioLab episode discusses the case that launched the controversial Milwaukee protocol – a technique for treating rabies that involves putting you into a drug-induced coma to protect your brain until your body has produced the anti-rabies antibodies.
It’s a fascinating and compelling episode so well worth checking out.
UPDATE: This old medical film on YouTube goes through the stages of rabies infection. Warning: it’s a bit gruesome and has a melodramatic soundtrack but it is quite informative.
Link to RadioLab episode ‘Rodney Versus Death’.
Mind Hacks 
Neat(if you like extremely grim topics)! Interesting virus, as it perpetuates itself by changing the behavior of the host. Ere was a name for this type of strategy but the label escapes me.
You have to wonder why the Milwaukee Protocol only worked on the one patient (all others had some pre-infection vaccination that is, before symptoms begin).
I’m assuming her work in a bat-infested church gave her some immunity via the aerosolized guano, as you can catch it that way too. However worth noting – bat rabies is far more curable than say, dog rabies.
I said that with an Irish accent.
Another great video is here https://www.youtube.com/watch?v=AEQ_fBcXQRQ
@Amelie There has been more than one case of survival of rabies in the literature and history, one in recent-ish case in particular was in a woman who had an atypical presentation and recovered prior to the antibody test coming back! She did not have treatment for rabies and yet survived with little treatment, and a few months down the track was unfortunately lost to follow up. The one thing in common between all the survivors seen is that they mounted a vigorous immune response with positive antibodies but never had detectable viral RNA on PCR.
Here is an article about rabies treatment from prior to Milwaukee Protocol: http://cid.oxfordjournals.org/content/36/1/60.long
And a recent case from the NEJM: http://www.nejm.org/doi/full/10.1056/NEJMcpc1209935
Dear Tom,
The swallowing problem is also a characteristic of people with Parkinson’s disease. ARe there any related mechanisms?
I also thank you for this morning’s interesting BBC blog on drug addiction and especially your final comment “Science may serve our collective anxieties rather than informing us”.
I am sure future generations will quote that when they evaluate today’s carbon dioxide hysteria.
Cheers, Eric Danell, plant physiologist and Dokmai Dogma blogger.
Eric-
Parkinson’s (and strokes) generally causes dyscoordination of swallowing where the signals to the muscles are out of sync, while rabies causes forceful, painful spasms.
hope that helps?