Lung Worm – The Circle of Life

How is a snail and a mouse relevant to a coughing cat?
The species of parasite called aelurostrongylus abstrusus (cat lung worm) spends the larval stage of its life cycle in snails and slugs. These slugs are then ingested by a rodent or a cat and the larvae migrates from the gut to the lung over a 24hour period.

What happens when an infected cat coughs?
Once the lung worm is an adult living in the lung of the cat it starts to reproduce and deposits eggs which hatch and grow into larvae. The larvae irritate the respiratory tract and cause coughing. When the cat coughs the larvae will leave the lung, enter the mouth of the cat where they are swallowed into the digestive tract and passed in the faeces.

How do snails get the lung worm larvae?
Once the larvae are passed in the faeces they need to find a new host. They actively penetrate into passing snails or slugs. The snails or slugs may be ingested by a cat or another host.

What about other hosts?
Infected snails and slugs may also be ingested by rodents, frogs, lizards or birds. Cats that hunt these animals may pick up lung worm.

Should I worry?
Lung worm doesn’t often cause serious disease in the cat, however if your cat is coughing further testing may be recommended. The risk of infestation can be reduced through limiting hunting and regular de-worming.