Garden slugs aren’t poisonous or venomous. Their slime and bodies hold no toxin meant to harm people or pets.1Mendocino Animal Hospital. Are Slugs Slugs Poisonous to Dogs? The risk comes from what they pick up from their surroundings, because they can carry parasites and germs.2Mendocino Animal Hospital. Are Slugs Slugs Poisonous to Dogs? That makes swallowing a slug, whether you, a child or a dog does it, far more worrying than touching one. The main concerns are the rat lungworm parasite in warm regions such as Hawaii, parts of the southern US and the Asia Pacific, a related lungworm in dogs, and gut bacteria.
What Slug Slime Is and Whether Touching One Is Harmful
Slug slime is a gel. It’s a mix of sugary polymers, proteins and metals such as copper, iron and zinc, which help it hold together.3PubMed Central. Biological activities of gastropods secretions: snail and slug slime Common slug mucus doesn’t even stick well to human skin.4PubMed Central. Biological activities of gastropods secretions: snail and slug slime A slimy hand is messy, but it isn’t poisoned, and you shouldn’t expect a rash or poisoning symptoms from skin contact alone.
Common garden slugs can carry live E. coli on their bodies for up to 14 days in lab tests.5PubMed Central. Slugs: Potential Novel Vectors of Escherichia coli O157 The droppings of the common Spanish slug carry a range of gut bacteria, and some of them are resistant to common antibiotics.6PubMed. Diversity of enterobacteria including β-lactamase producing isolates associated with the Spanish slug (Arion vulgaris) Wash your hands with soap after handling slugs or slimy produce.
Slime can be stubborn and smeary, so wipe it off with a dry paper towel first. The soap-and-water wash then works better. Keep your hands away from your face, eyes and food until they’re clean. Children who play with slugs should wash before snacks or meals.
Rat Lungworm, the Main Risk From Eating a Slug
Rat lungworm is a parasitic worm whose adults live in rats.7PubMed Central. Biology, systematics, life cycle, and distribution of Angiostrongylus cantonensis, the cause of rat lungworm disease Slugs and snails pick up the young worms by eating rat droppings.8Parasitology. Angiostrongylus cantonensis and neuroangiostrongyliasis (rat lungworm disease): 2020 The larvae can only become infectious inside a slug or snail,9Parasitology. Angiostrongylus cantonensis and neuroangiostrongyliasis (rat lungworm disease): 2020 so an infected slug is the parasite’s route into a person.
People get infected by eating raw or undercooked snails or slugs.10Hawaii State Department of Health. Neuroangiostrongyliasis Eating raw produce with a tiny slug, or part of one, on it can also do it.11Hawaii State Department of Health. Neuroangiostrongyliasis Unwashed lettuce carrying a slug is a not-uncommon source.12PubMed Central. Clinical aspects of eosinophilic meningitis and meningoencephalitis caused by Angiostrongylus cantonensis, the rat lungworm Young children sometimes eat slugs they find outdoors, too.13NSW Government. Rat lung worm disease fact sheet
Not every slug is a risk. A slug is only a carrier if it has eaten droppings from an infected rat, so most slugs in most gardens carry nothing. How many are infected varies widely from place to place, which means a garden near a known problem area is a different situation from one far away. You can’t tell an infected slug from a clean one by size, colour or slime, so a close look gives no reassurance. In warm regions where rat lungworm is established, treat any raw slug as a possible carrier.
The parasite is widespread throughout Asia Pacific and is the leading cause worldwide of a type of meningitis.14PubMed Central. The potential danger of eating wild lettuce: a brief review of human rat lungworm infection Its range is expanding in North America.15PubMed Central. Geographic Range Expansion for Rat Lungworm in North America It can also infect slugs common in Europe, so warming may let it spread.16PubMed Central. Diverse Gastropod Hosts of Angiostrongylus cantonensis, the Rat Lungworm, Globally and with a Focus on the Hawaiian Islands In cooler regions the risk is low, but it isn’t zero.
Symptoms of Rat Lungworm and When to See a Doctor
Infection usually causes headache and nerve symptoms, such as tingling or weakness in the muscles of the face.17PubMed Central. The potential danger of eating wild lettuce: a brief review of human rat lungworm infection It usually clears up on its own.18PubMed Central. The potential danger of eating wild lettuce: a brief review of human rat lungworm infection But the range of illness is wide, running up to inflammation of the brain, coma and, rarely, death.19PubMed Central. Clinical aspects of eosinophilic meningitis and meningoencephalitis caused by Angiostrongylus cantonensis, the rat lungworm
Treatment includes spinal taps to ease pressure and headache, steroids for inflammation, and the deworming drug albendazole.20PubMed Central. Guidelines for the diagnosis and treatment of neuroangiostrongyliasis: updated recommendations If you know a raw slug was eaten in a warm region, call a doctor right away rather than waiting for symptoms.
When you call, say exactly what was eaten and when, such as a slug on lettuce at lunchtime yesterday, because timing helps the doctor judge what to watch for. Mention where you live and any recent travel, since rat lungworm is far more likely in some regions than others. Report symptoms that stand out, such as a severe headache, stiff neck, or tingling or pain in the skin.
If a child licked or swallowed a slug, note the time and roughly how much was eaten, whether a lick, a bite or a whole slug. Rinse the child’s mouth with water and wash their hands, which removes slime and surface germs. In a warm area where rat lungworm occurs, call a doctor the same day rather than waiting to see what happens. In cooler regions the risk is low, so watch over the following weeks for headache, vomiting or unusual behaviour, and call a doctor if any appear.
How to Wash Garden Lettuce and Cook Safely
Vinegar, salt and bleach solutions removed slugs no better than tap water.21PubMed Central. Effects of washing produce contaminated with the snail and slug hosts of Angiostrongylus cantonensis with three common household solutions Some slugs stayed on lettuce even after washing, and only rinsing each leaf individually removed all of them.22PubMed Central. Effects of washing produce contaminated with the snail and slug hosts of Angiostrongylus cantonensis with three common household solutions Even then, washing may not remove slime or kill larvae in it.23PubMed Central. Effects of washing produce contaminated with the snail and slug hosts of Angiostrongylus cantonensis with three common household solutions
In practice, pull the head apart and rinse every leaf separately under running water. A slug can hide inside a tightly packed head and survive a quick dunk in a bowl. Look at the folds and the base of each leaf, where small slugs and slime tend to lodge. In areas where rat lungworm occurs, throw away any leaf with a slime trail, and cook leafy greens, since heat kills the larvae.
The larvae die at around 50 to 55 °C.24PubMed. Effect of Freezing and Boiling on the Infectivity of Third-Stage Larvae of Angiostrongylus cantonensis Present in Land Snails and Freshwater Prawns Even so, boiling snails for just 1 minute left some larvae alive, while 2 to 3 minutes did not.25PubMed. Effect of Freezing and Boiling on the Infectivity of Third-Stage Larvae of Angiostrongylus cantonensis Present in Land Snails and Freshwater Prawns
If you collect rainwater, keep tanks covered and filter the water. Don’t drink untreated catchment water in areas where rat lungworm occurs.
Are Slugs Dangerous to Dogs
Dogs get a lungworm by eating infected slugs or snails.26PubMed Central. Canine angiostrongylosis: recent advances in diagnosis, prevention, and treatment It mainly affects the heart, lungs and blood clotting.27PubMed Central. Canine angiostrongylosis: recent advances in diagnosis, prevention, and treatment Signs include cough and fast or difficult breathing, and untreated it can become life-threatening.28PubMed Central. Canine angiostrongylosis: recent advances in diagnosis, prevention, and treatment
Coughing or tiring quickly on walks is one of the commonest early clues. Because lungworm affects blood clotting, unusual bleeding or bruising is a warning sign that needs prompt attention. Some dogs show only vague signs such as a poor appetite or low energy, so the lack of a cough doesn’t rule it out. Signs can appear weeks after the slug was eaten, so a dog that seems fine afterwards isn’t necessarily in the clear.
Ask your vet about lungworm preventives, which are the most dependable protection and can be matched to where you live. Pick up toys and water bowls left outside overnight, since slugs crawl on them and dogs can swallow them unnoticed. Discourage your dog from eating grass and from sniffing out slugs, since slugs can be swallowed with either. If your dog eats slugs often, tell the vet, who can advise on testing and preventive treatment.
Slug Bait Is More Poisonous Than Slugs
The more immediate poison in a garden is often the bait meant to kill slugs. Metaldehyde slug bait can poison dogs, often causing seizures.29PubMed Central. A prospective study on clinical signs, management, outcomes, and delayed neurologic sequelae due to metaldehyde poisoning in 26 dogs Treatment works for most: about 8 in 10 poisoned dogs survived with treatment, and all dogs given activated charcoal or made to vomit at the vet survived.30PubMed Central. A prospective study on clinical signs, management, outcomes, and delayed neurologic sequelae due to metaldehyde poisoning in 26 dogs Get to a vet immediately rather than waiting for symptoms.
Take the packaging with you, because the product name and active ingredient help the vet choose treatment quickly. Don’t try to make your dog vomit at home unless a vet tells you to, since it can be unsafe and may cause delay. Phone ahead to the clinic while you travel so the team can prepare. Watch for tremors, twitching or heavy drooling on the way, as these suggest the poison is taking effect, and tell the vet if you see them. Dogs that recovered from seizures with treatment had no lasting problems over 3 years.31PubMed Central. A prospective study on clinical signs, management, outcomes, and delayed neurologic sequelae due to metaldehyde poisoning in 26 dogs
Safer Ways to Keep Slugs Away
- Copper strips: placed around pots or beds, they deter slugs.32Eartheasy. Natural Slug Control
- Barriers: wood ash, diatomaceous earth or cinders slow slugs down.33UC Santa Cruz. Non-Chemical Snail & Slug Control
- Beer traps: sunk to the rim, they attract slugs, with mixed success.34Eartheasy. Natural Slug Control35UC Santa Cruz. Non-Chemical Snail & Slug Control
- Electronic fences: a non-toxic option for protecting beds.36Eartheasy. Natural Slug Control
If a dog uses the garden, skip pellets entirely. Ash barriers wash away, so refresh them after rain. No single method is reliable alone, so combining several gives the best results.
Wear gloves when picking slugs off plants by hand, which keeps slime and germs off your skin. Wash your hands after emptying traps, since the contents can carry bacteria. Keep rats away from the garden, because rats spread rat lungworm and so keep the parasite cycle going. Keep children away from traps, which can hold slugs and liquid they might touch or taste.