Small parasite, big trouble

By John Morgan | Dated June 4, 2022

Millie is on the road to recovery after her rat lungworm scare.

Millie was brought into Gordon Vet Hospital when her owners noticed she seemed a bit off-colour. The normally energetic puppy was quiet, sleepy and even a little off her food. After a full examination, Dr. John Morgan found that she was painful in her back and neck and beginning to show some signs of weakness in her back legs. Immediately, he began to suspect an infection with rat lungworm.

Rat lungworm (Angiostrongylus cantonensis) is a parasite that reproduces in the lungs of rats. The parasitic larvae can be spread to slugs and snails where they can become infectious to any animal that decides to snack on these slippery bugs. This is the start of the bizarre stage of the parasite’s lifecycle – the larvae migrate up the spinal cord and can even reach the brain. This causes a huge amount of inflammation which leads to pain and decreased nerve function. If left untreated, this parasite can cause paralysis, meningitis, blindness and even death! Puppies seem particularly at risk of infection, partly due to their inquisitive nature but also because their immune system and natural defenses are not quite fully developed.

Luckily for Millie, quick action by her owners and Dr. John means that she received treatment early and is now back to her usual antics at home (although hopefully avoiding snacking on any more snails!).

It is important to remember that while we always strongly recommend stopping puppies from eating snails and slugs that many snail and slug baits are highly toxic to pets and should not be used in areas where pets have access. Often a beer trap or keeping puppies out of the backyard during the night hours can be helpful.