Subject:  Rat Lung Worm

From a visitor to the vet clinic…..

“I’ve heard about rat lung worm disease and that it is found in rats, transmitted by snails and that tawny frogmouths often seem to die from it. Can it be passed onto any other animals and what are the issues for carers dealing with these animals? Do blue tongue lizards get infected if they eat infected snails? Can humans get infected and what are the symptoms and outcomes?”

Derek answers…….

Angiostrongylus cantonensis is the scientific name for the rat lung worm. It cycles between snails and rats, spending time in rats’ brains and lungs. Other hosts can be affected by accidentally eating snails or eating plant matter (including vegetables and fruit) over which heavily infected snails have crawled. This makes organic produce particularly risky and these should always be washed thoroughly before being eaten. The worms migrate to the central nervous system (brain and spinal cord) where they can cause meningitis or meningo-encephalitis (e.g. in dogs). The worm may migrate along the spinal cord causing paralysis. Many mammalian and bird species can be affected, including humans, but I don’t know of any cases where reptiles have been affected. The species most obviously affected are tawny frogmouths and brushtail possums. Signs associated with larval damage include neurological dysfunctions (e.g., paresis, paralysis, ataxia, blindness) depending on which parts of the central nervous system are affected and how severe the damage is. Humans are affected if they eat raw contaminated vegetables or fruit, infested snails or slugs, or infested intermediate hosts. So don’t eat raw snails or slugs and don’t eat other uncooked animals.

Dr Derek Spielman

From a reader …. 

Dear WAIF newsletter.

I read your ‘Q&A’ regarding the Strong Rat Lung Worm and wanted to share my experience as a warning to those who may live close to this lovely worm, and may not be taking as much care as they should.


I am a human (!) and I have had the pleasure of an infestation of Strong Rat Lung Worms.  It nearly killed me. I believe I ingested the larvae from a snail trail on unwashed produce at a restaurant (?).  Subsequently, for a week I suffered a hideous itch all over my body, so bad that I couldn’t sleep.  The larvae were not killed by the stomach fluids.  They had hatched and made their way around my body and to my brain.  The itching subsided somewhat and I had the classic meningitis symptoms of severe headaches, sores, fever, light-sensitivity, rigors, dehydration and vomiting.  On admittance to hospital they took a lumbar puncture to look at my spinal fluid, which showed neither viral, nor bacterial meningitis.  I completely lost my sight and from then on remember nothing.  My husband tells me I became aggressive and foul-mouthed and had to be sedated.  An MRI showed nothing because the worms moved and so weren’t picked up.  Nobody knew what to do.  I lost 10 days.  I was in and out of intensive care and stopped breathing twice. Luckily the hospital had a neurologists’ conference and my case was discussed.  A visiting neurologist suggested it may be parasites.  There was nothing to loose by treating me… The treatment is similar to that for a dog – “worming tablets”.  The next morning I regained consciousness and ate scrambled eggs.  A subsequent MRI showed the now-still worms; they are like a 2” long hairs.  My eyesight returned.  I lived.  I had recovered, but then had a battle with severe pain, requiring much morphine and high steroids.  I have damage to my nerves, my spine and my Central Nervous System, which means a life of pain management, using drugs.  Amazingly my eyesight had improved when it returned: I went from -5 to -3. (I reckon two more infestations should do it!) 

I consider my Neurologist my second-best friend.  However,  I was lucky - a 2 year old in Melbourne ate a snail and died.  Shortly after I was ill, I heard of a drunken footie player who’d accepted a $10 bet to swallow a slug and ended up in a coma at the same hospital.  He recovered after “worming”,  with some nerve damage.

It is more common than you would probably imagine.


So please do heed Dr Derek Spielman’s warnings: “organic produce…. should always be washed thoroughly before being eaten…. and don’t eat raw snails or slugs”.  It definitely is worth the extra few minutes of washing lettuce or cabbage etc to be certain.


Julia (not yet vegetarian). 


Wildlife Assistance & Information Foundation