Rat lung worm or Angiostrongylus cantonensis is a parasite that mainly lives in rodents such as rats and can infect snails and slugs that come into contact with infected rat faeces. People can be infected when they eat an infected snail or slug.
Most people may have no symptoms at all. Others may have only mild, short lived symptoms.
Very rarely, rat lung worm causes an infection (infestation) of the brain called eosinophilic meningo-encephalitis. People with this condition may have headaches, a stiff neck, tingling or pain in the skin, fever, nausea, and vomiting. The time between eating the slug or snail and getting sick is usually 1-3 weeks.
Anyone with these symptoms should seek medical assessment although other infections (such as meningococcal disease or pneumococcal disease) are much more likely causes of meningitis in children.
The adult worms are found in rats. Infected rats excrete the parasite larvae in their faeces. The parasites can then infect snails and slugs that come into contact with infected rat faeces.
People can be infected when they deliberately or accidentally eat a raw snail or slug that contains the lung worm larvae or if they eat unwashed lettuce or other raw leafy vegetables that have been contaminated by the slime of infected snails or slugs. People infected with rat lung worm do not pass the infection on to others.
The parasite is more common in some parts of the world, especially in Southeast Asia, the Pacific Islands and Australia. People are at risk if they eat raw snails or slugs infected with this parasite, either deliberately or accidentally. For example:
Rat lung worm disease can be prevented by some simple measures:
Consider controlling snails and slugs around vegetable patches and gardens and control vermin around the home. If snail pellets or rodent baits are used it is very important that precautions are taken to ensure young children don't accidentally eat them.
Preventive treatment with a prescription medication (albendazole) may be considered in cases where there has been a witnessed ingestion of any part of a snail or slug within the last 7 days. Discuss this with your general practitioner who will refer to local health department guidelines.
There is no vaccine to prevent this illness.
People with meningitis caused by rat lung worm often have high numbers of certain immune cells called eosinophils in their blood or cerebrospinal fluid and this may suggest the diagnosis.
Most people with symptoms recover fully without treatment over days, weeks or months.
However, the infection can sometimes cause severe meningitis that requires specialist treatment. The infection is occasionally fatal.
Rat lung worm is not a notifiable disease in NSW as it is an extremely rare infection.
The Sydney Children’s Hospital Network Snail and slug ingestion practice guidelines.
For further information please call your local public health unit on 1300 066 055.