Snail: lean meat with a parasite problem

The best tested number connected to snails comes from a hospital. A Cochrane review of parasitic eosinophilic meningitis found one eligible trial, with 110 patients, in which prednisolone shortened the median time until headache cleared from 13 days to 5. That is moderate quality evidence about treatment, and it says nothing about prevention. The parasite behind the snail outbreaks below, the rat lungworm, turns up in the snails people eat. Pooled surveys in China from 2005 to 2015 found it in 21.5 percent of giant African snails and 7.6 percent of golden apple snails, a count of infected snails and not a risk per meal. When 17 Thai workers in Taiwan ate raw apple snails, all developed severe headache within 4 to 23 days and 12 went on to eosinophilic meningitis. As food, the single USDA record for raw snail, species not named and with no cooked version, gives 90 calories, 16.1 g protein, 1.4 g fat and 3.5 mg iron per 3.5 oz (100 g).

The numbers, per 3.5 oz (100 g)

How much is actually in it

• Raw snail meat in the USDA record has 90 calories, 16.1 g protein, 1.4 g fat, 3.5 mg iron and 250 mg magnesium per 3.5 oz (100 g). — USDA SR Legacy record Mollusks, snail, raw (n = 1 record) Evidence E source
  Energy 90 calories, protein 16.1 g, fat 1.4 g, iron 3.5 mg, magnesium 250 mg, selenium 27.4 ug per 3.5 oz (100 g)

What cooking and storage change

• In 125 Taiwan cases of eosinophilic meningitis, mostly in children, the giant African snails had been cooked thoroughly and held only dead larvae, so infection was suspected to come from handling the raw snails during preparation. — 125 cases of eosinophilic meningitis in southern Taiwan, 1968-1969 (n = 125) Evidence D source
  Most cases among children; cooked snail meat contained only dead larvae

Safety, limits and interactions

• A Cochrane review of parasitic eosinophilic meningitis found one eligible trial of 110 people, in which prednisolone cut median headache duration from 13 to 5 days. — Patients with parasitic eosinophilic meningitis (n = 110 (1 RCT)) Evidence A source
  Median time to headache resolution 5 vs 13 days, P < 0.0001
• In a double-blind trial of 110 patients with eosinophilic meningitis, 2 weeks of prednisolone 60 mg a day left 5 patients with headache at day 14 against 25 on placebo. — Patients with eosinophilic meningitis in Thailand (n = 110) Evidence B source
  Headache at 14 days 5 vs 25; median time to headache resolution 5 vs 13 days; repeat lumbar puncture 7 vs 22
• Pooled surveys of edible snails in China found the rat lungworm in 21.5% of giant African snails and 7.6% of golden apple snails. — 41,299 Pomacea canaliculata and 21,138 Achatina fulica snails in 38 studies, China 2005-2015 (n = 38 studies) Evidence C source
  Infection 7.6% (95% CI 6.3 to 9.0) in P. canaliculata, 21.5% (18.4 to 24.5) in A. fulica; OR 3.946 A. fulica vs P. canaliculata
• In a 2011 outbreak in Dali, 9 of the 16 people who ate a Pomacea snail dish got eosinophilic meningitis, and neither of the 2 who skipped it fell ill. — 18 people who shared a meal, Dali City, China (n = 18) Evidence C source
  Attack rate 56.3% among snail eaters vs 0 of 2 non-eaters; market snails 7.3% infected
• Among 17 Taiwan workers who ate raw apple snails, all got severe headache within 4 to 23 days and 12 developed eosinophilic meningitis. — Thai laborers in Kaohsiung, Taiwan, 1998-1999 (n = 17) Evidence C source
  Eosinophilic meningitis 12 of 17 (71%); larvae in all 12 tested snails
• Two people had digoxin-like heart poisoning after an escargot stew, traced to oleandrin from oleander that the snails had eaten. — Two adults, aged 43 and 66 (n = 2) Evidence D source
  Snail tissue 0.282 nmol/g digoxin equivalents; symptoms resolved by day 3

Who this works differently for

• A woman on peritoneal dialysis needed a ventilator after eating sea snails, because tetramine, normally cleared quickly by the kidneys, built up. — One 48-year-old woman with end-stage kidney disease on peritoneal dialysis (n = 1) Evidence D source
  Respiratory failure, mechanical ventilation 5 days, full recovery by day 15
• A 12-year-old on house dust mite immunotherapy had anaphylaxis after eating snail, with lab tests showing cross-reactivity between mite and snail allergens. — One 12-year-old girl on dust mite immunotherapy (n = 1) Evidence D source
  Anaphylaxis; RAST inhibition showed mite-snail cross-reactivity

The bottom line

Cooking matters, and the old records suggest it may not be enough on its own. In 125 cases of eosinophilic meningitis in southern Taiwan in 1968 and 1969, most of them children, the giant African snails had almost always been eaten thoroughly cooked and the cooked meat held only dead larvae. The investigators suspected that larvae released while the snails were being prepared caused the infections, a suspicion they did not measure. If that is right, handling raw snails in the kitchen is part of the risk. At a 2011 meal in Dali, China, 9 of the 16 people who ate a Pomacea snail dish fell ill and neither of the 2 who skipped it did, though the report does not say how the snails were cooked. Who should be careful comes from single cases, which show that something can happen and not how often. Two adults developed digoxin-like heart poisoning after an escargot stew made from wild-collected snails that had fed on oleander, and their symptoms cleared by day 3. A 48-year-old woman on peritoneal dialysis needed a ventilator for 5 days after eating sea snails, because tetramine, which working kidneys clear quickly, built up in her body. A 12-year-old girl on house dust mite immunotherapy had anaphylaxis after eating snail, and her lab tests showed mite and snail allergens cross-reacting. We have no card on snails in pregnancy or alongside medicines.

Sources

1. snl-r3-10 · USDA FoodData Central SR Legacy, dataset
   Mollusks, snail, raw (FDC 167744): energy 90 kcal; protein 16.1 g; fat 1.4 g; iron 3.5 mg; magnesium 250 mg; selenium 27.4 ug; copper 0.4 mg per 100 g
   USDA FoodData Central, SR Legacy 2019, FDC 167744 · checked 2026-09-29
2. snl-r3-06 · Case series
   However, in almost all instances the snail was eaten after it had been thoroughly cooked and examination of cooked snail meat revealed only dead larvae. It is suspected that patients became infected by inadvertently ingesting A. cantonensis larvae liberated when the snails were prepared for consumption.
   Am J Trop Med Hyg, 1975 · checked 2026-09-29
3. snl-r3-01 · Cochrane systematic review
   One study involving 110 participants (55 participants in each group) met our inclusion criteria. ... The corticosteroid (prednisolone) showed a benefit in shortening the median time to resolution of headaches (five days in the treatment group versus 13 days in the control group, P value < 0.0001).
   Cochrane Database Syst Rev, 2015 · checked 2026-09-29
4. snl-r3-02 · Randomized controlled trial
   There were significant differences between the treatment and control groups, with regard to the number of patients who still had headache after 14 days (5 vs. 25, respectively; P=.00004), the median length of time until complete disappearance of headache (5 vs. 13 days, respectively; P=.00000), and the number of patients who had repeat lumbar puncture (7 vs. 22, respectively; P=.002).
   Clin Infect Dis, 2000 · checked 2026-09-29
5. snl-r3-03 · Meta-analysis of prevalence studies
   The overall infection rate of A. cantonensis in China was estimated to be 7.6 % (95 % confidential interval (CI) = 0.063 to 0.090) in P. canaliculata and 21.5 % in Ac. fulica (95 % CI = 0.184 to 0.245), respectively.
   Parasitol Res, 2016 · checked 2026-09-29
6. snl-r3-04 · Outbreak investigation
   Of 18 persons, 16 consumed Pomacea snail food and 9 were infected with an infection rate of 56.3%. The two persons who did not consumed snail food were not infected.
   Zhongguo Xue Xi Chong Bing Fang Zhi Za Zhi, 2011 · checked 2026-09-29
7. snl-r3-05 · Retrospective cohort
   We enrolled 17 Thai laborers in whom severe headache and eosinophilia developed within 4 to 23 days after eating raw snails. Twelve (71%) developed eosinophilic meningitis.
   Am J Med, 2001 · checked 2026-09-29
8. snl-r3-08 · Case report
   The presence of oleandrin and oleandrigenin in the snails was confirmed by liquid chromatography-tandem mass spectrometry analysis
   J Anal Toxicol, 2006 · checked 2026-09-29
9. snl-r3-07 · Case report
   Most of these symptoms are mild and spontaneously resolved due to the rapid excretion of tetramine through the kidneys; however, patients with kidney dysfunction can present severe symptoms.
   Medicina (Kaunas), 2021 · checked 2026-09-29
10. snl-r3-09 · Case report
    Children undergoing HDM immunotherapy treatment should be aware of the potential risks of hypersensitivity reactions to invertebrate foods.
    Pediatr Allergy Immunol, 2000 · checked 2026-09-29