Eating slugs can potentially paralyze you due to a parasite that some slugs and snails can carry called rat lungworm. Rat lungworm can cause a rare type of meningitis that may result in paralysis. However, the chances of getting rat lungworm from eating a slug is low, and thoroughly cooking the slug would kill the parasite.
What is rat lungworm?
Rat lungworm, also known as Angiostrongylus cantonensis, is a parasitic worm that can infect the brains and spinal cords of humans. The adult form of the parasite lives in the lungs of rats. The larvae form of the parasite lives in slugs and snails. Humans can become infected by eating raw or undercooked slugs, snails, or other animals that may eat infected slugs/snails such as freshwater prawns, crabs, or frogs.
When humans ingest the parasite, the larvae penetrate the intestinal wall and travel through the bloodstream to the brain and spinal cord. Here they develop into young adult worms which get “lost” in the central nervous system where they cannot complete their lifecycle. However, their presence can trigger an inflammatory immune response leading to eosinophilic meningitis or meningoencephalitis, a rare type of meningitis caused by the presence of eosinophils (a type of white blood cell) in the brain and spinal cord.
What are the symptoms of rat lungworm infection?
The symptoms of rat lungworm infection can include:
- Severe headache
- Stiff neck
- Tingling or painful feelings in the skin
- Low-grade fever
- Nausea and vomiting
- Fatigue
- Temporary paralysis of the face
- Limb weakness or numbness
- Seizures
Symptoms usually appear 1-3 weeks after ingesting the parasite. Most people recover fully, but it can take weeks to months to recover. In rare cases, especially if the parasite migrates to the brain, the infection can cause coma, severe brain damage or even death.
Can rat lungworm cause paralysis?
Yes, rat lungworm infection can sometimes cause temporary or permanent paralysis. This occurs when the parasite travels to the brain and/or spinal cord, triggering swelling and damage. If the worms migrate to the central nervous system, they can damage neurons that control muscle movement, resulting in paralysis. The face is most commonly affected, but some people experience full body paralysis.
Most cases of paralysis are temporary, lasting a few days up to several weeks. But in rare cases, the paralysis can become permanent. This is more likely to occur if there is substantial brain or spinal cord inflammation that causes irreversible damage.
What are the chances of getting infected from eating slugs?
The chances of becoming infected with rat lungworm from eating a slug is overall low, even in areas where the parasite is endemic. Here are some estimates on the risk:
- In Hawaii, where rat lungworm is prevalent, only 1 in 5,500 slugs may be infected with the parasite.
- Eating a single infected slug has about a 1 in 1,000 chance of causing rat lungworm disease.
- Overall, the odds of contracting rat lungworm in Hawaii is estimated to be 1 in 8,000 per year among residents who eat slugs/snails.
However, the raw number of cases in Hawaii has risen in recent years as slug and snail eating has become more popular. From 2007-2017, Hawaii saw 82 cases of rat lungworm disease. So while the risk per individual slug is low, more cases are occurring due to higher overall consumption.
Who is most at risk of rat lungworm?
Those most at risk include:
- People living in or visiting areas where rat lungworm is endemic, primarily Hawaii but also parts of Southeast Asia and the Pacific Islands.
- People who purposefully eat raw or undercooked slugs/snails as part of a food dare or tribal practice.
- People who accidentally ingest slugs/snails on produce due to poor washing practices.
- Young children who may accidentally ingest slugs/snails from the environment.
In non-endemic areas like the continental US, locally acquired cases are rare but a few occurrences have been documented in Louisiana, Florida and California. International travelers who eat slugs/snails also potentially risk infection.
Should you eat slugs or snails raw?
No, it is not recommended to purposefully eat slugs or snails raw due to risk of transmitting rat lungworm and other parasites. The safest approach is to avoid eating slugs/snails entirely. However, if you choose to eat these, they should be thoroughly cooked first to kill any parasites.
Eating raw slugs/snails is an unnecessary risk to take for a food dare or tribal practice. For example, a teen in Hawaii was left paralyzed after eating a raw slug as a dare. While most people recover fully, serious long-term effects are possible.
How to prevent rat lungworm infection
Here are some tips to prevent rat lungworm infection:
- Wash all fruits and vegetables thoroughly, especially leafy greens.
- Inspect and wash produce grown in your own garden.
- Control snail/slug populations in your garden.
- Avoid purposeful consumption of raw slugs/snails.
- Cook slugs/snails thoroughly if you choose to eat them.
- Prevent rats from entering homes and gardens.
- Use gloves when working outdoors in endemic areas.
Diagnosing rat lungworm
Diagnosing rat lungworm can be challenging because the symptoms are similar to other forms of meningitis. Diagnosis may involve:
- Medical history – asking about potential slug/snail exposure 1-3 weeks before symptom onset.
- Physical exam – checking for signs of meningitis.
- Spinal tap to look for eosinophils in the spinal fluid.
- MRI – may show signs of brain/spinal cord inflammation.
- Antibody blood test – can detect if the immune system is reacting to the parasite.
- PCR testing of spinal fluid – can detect DNA of the parasite.
Often, a combination of the patient’s exposure history, symptoms, and lab tests is required to confirm rat lungworm infection.
Treating rat lungworm
There are no drugs that can kill the parasite once it is inside the nervous system. Treatment focuses on:
- Pain relief with NSAIDs, opiates.
- Steroids to reduce CNS inflammation.
- Anticonvulsants for seizures.
- Physical therapy to help maintain or recover mobility.
Most symptoms resolve over time as the body’s immune system kills the worms and inflammation recedes. But recovery may take weeks to months. Supportive medical care helps manage symptoms in severe cases.
Prognosis and long-term outlook
The prognosis for most people with rat lungworm infection is excellent. According to the Hawaii Department of Health:
- Over 90% of people make a full recovery and have no long-lasting effects.
- Most mild symptoms resolve within 2-3 weeks.
- Moderate symptoms like limb weakness or numbness may take 2-3 months to fully resolve.
- In severe cases with neurological damage, recovery may take over a year.
- There have been 2 reported deaths attributed to rat lungworm in Hawaii since 2007.
Paralysis from rat lungworm is usually temporary. But in rare cases, permanent paralysis is possible if the worms cause irreversible spinal cord or brain damage. Children appear to be at higher risk of long-term neurological deficits. Prompt treatment is key.
Conclusion
In summary, eating raw slugs can transmit rat lungworm which may cause paralysis in rare cases. However, cooking them kills the parasite. Overall odds of infection are low from a single slug. Good hygiene when eating produce and avoiding raw slug consumption protects against rat lungworm disease.