Rat Lung Worm, also known as ANGIOSTRONGYLUS, is a worm about 20mm in length, which lives in the pulmonary artery in the rat, thus the name.  Adult worms lay eggs in the arteries which hatch into first stage larvae.  These larvae penetrate the artery wall to enter the lungs and migrate up the windpipe and into the gut and are expelled in the feces of the rodent.  Once outside the body, they survive in damp conditions and penetrate the skin of snails and slugs.  Snails and slugs can also become infected by eating rodent feces containing the larvae.  Then follows a further development stage within the snails and slugs.  Infection is spread back to the rat when rats eat snails and slugs, and larvae in the tissues of these mollusks penetrate through the gut wall into the circulation and reach the brain.  In the rat brain the larvae develop further, and when mature migrate through the rat body to the pulmonary artery where they mature to an adult worm.

We all know that puppies will eat anything or anything and everything goes in their mouths. 

If your puppy eats a slug or vegetables, grass, etc that has slug or snail trail on it or the mollusk itself, it is possible that your puppy/dog will become ill or infected.

Angiostrongylus or rat lung worm, can cause Eosinophilic Meningitis, which is an infection of the brain.    An increase of white blood cells is an indication of an infection .

Rat lung worm is a normal parasite in rats, just like roundworm is normal in dogs. 

Eating an infected slug, or even eating vegetation with a slug trail on it, can cause infection.  The larvae progresses through the gut right through the body and takes up residence INSIDE the spinal cord where it turns into a worm.  This causes progressive hind limb paralysis and extreme lumbar region pain.  Humans can also develop this infection/disease.

In humans the symptoms to watch for are: nausea, vomiting, mild fever, stiff neck, abdominal pain, loss of sight or blindness, coughing.

In canines, as best as I can detect, look for a progressive paralysis of hind end, mild fever, go off their food, loss of balance as a result of the slow paralysis.

Treatment:

It seems from the reading I've done that a lumbar puncture of spinal tap is needed to test and analysis the cerebral spinal fluid for any abnormalities.  Both a blood test and cerebralspinal fluid will have elevated levels of eosinophils.  White blood cell count will be elevated.  Some have been given high doses of corticosteroids to combat the spinal cord damage.

It should be noted that giving an anti-worm medication can only worsen this condition because a dead worm within the spinal cord causes even more damage or even death.

The worm has to make it's own way out of the body, but there is extreme danger the worm will migrate and lodge in the brain, causing death.  Hopefully , it will work it's way into the gut to be passed out in the feces.     

One of the sites accessed for research on this article can be seen at http://www.medicdirect.co.uk/clinics/default.ihtml?step=4&pid=2073