{
  "slug": "wild-berry-fox-tapeworm",
  "question": "What are the odds of getting a fatal fox tapeworm infection from eating wild berries?",
  "category": "health",
  "tags": [
    "food",
    "travel"
  ],
  "no_reliable_estimate": false,
  "perceived": {
    "description": "The fear circulates widely in central Europe: a single unwashed raspberry or blueberry picked at fox-height could deliver Echinococcus multilocularis eggs that silently grow a parasitic tumor in the liver for years, often undetected until the disease is advanced. Health warnings routinely name wild berries and mushrooms as vectors, and the word \"fox tapeworm\" carries an outsized dread relative to how rare the actual disease is.\n",
    "rough_estimate": "many central Europeans estimate at least 1 in 1,000 risk for regular foragers",
    "kind": "intuition"
  },
  "native": {
    "display": "~0.20 per 100,000 per year (southwest Germany, 2012–2019)",
    "numerator": 2,
    "denominator": 1000000,
    "unit": "per year",
    "population": "adults in an endemic region of central Europe (southwest Germany)"
  },
  "normalized": {
    "lifetime_us_adult": 0.000118,
    "display": "~1 in 8,500 lifetime (endemic central European adult)",
    "log_value": -3.928,
    "assumptions": "Uses the most recent peer-reviewed incidence figure for an endemic European region: 0.20 cases per 100,000 per year in southwest Germany (2012–2019), from Graeter et al. (Infection 2020). That annual rate of 2.0 × 10^-6 per person, compounded over 59 adult years, yields 1 − (1 − 0.000002)^59 ≈ 0.000118, or about 1 in 8,500. This is the risk for an adult living in an actively endemic European region; the EU mean from the KNOW-PATH systematic review (1997–2023) is 0.063/100,000, yielding a lower-bound lifetime estimate of about 1 in 27,000. The Doubs département in France and Swiss Jura regularly record rates of 1.0–1.4/100,000, giving an upper-bound lifetime estimate of about 1 in 1,200. US adults face meaningfully lower baseline risk: Echinococcus multilocularis has limited US distribution (north-central states, Alaska), human cases are not nationally reportable, and recorded cases are sporadic — reliable US incidence data does not exist.\n",
    "uncertainty": {
      "low": 0.0000372,
      "high": 0.000826
    },
    "scope": "subgroup_lifetime"
  },
  "sources": [
    {
      "url": "https://pmc.ncbi.nlm.nih.gov/articles/PMC7674360/",
      "title": "Spatial distribution and incidence trend of human alveolar echinococcosis in southwest Germany: increased incidence and urbanization of the disease?",
      "publisher": "Infection (Springer); Graeter et al.",
      "source_type": "peer_reviewed",
      "statistic": "Annual AE incidence per 100,000: 0.12 (2004–2011), rising to 0.20 (2012–2019) in southwest Germany",
      "excerpt": "\"The data from our regional referral center for AE in southwest Germany suggest rising regional incidence for AE (annual incidence per 100,000 population 2004–2011: 0.12; 2012–2019: 0.20).\"\n",
      "source_date": "2020-11-20",
      "source_accessed": "2026-05-01",
      "archive_url": "http://web.archive.org/web/20250215061249/https://pmc.ncbi.nlm.nih.gov/articles/PMC7674360/",
      "calculation_notes": "Anchor for native rate. 0.20 per 100,000 per year = 2.0 × 10^-6 annual hazard per person. Lifetime probability over 59 adult years: 1 − (1 − 0.000002)^59 = 0.000118 ≈ 1 in 8,475. Chosen as native because it is the most cited recent peer-reviewed figure for a well-defined endemic region with active surveillance.\n"
    },
    {
      "url": "https://pmc.ncbi.nlm.nih.gov/articles/PMC5531747/",
      "title": "Potential risk factors associated with human alveolar echinococcosis: Systematic review and meta-analysis",
      "publisher": "PLOS Neglected Tropical Diseases; Piarroux et al.",
      "source_type": "peer_reviewed",
      "statistic": "Meta-analysis OR for 'ate unwashed strawberries': 1.39 (95% CI 0.87–2.23, p=0.17, not significant); 'ate wild vegetables and fruit': OR 1.38 (95% CI 0.90–2.10, p=0.14, not significant). Strongest risk factors: dog ownership including dogs that hunt, farming, rural residence in endemic areas.\n",
      "excerpt": "\"Results were not statistically significant for 'ate unwashed strawberries' (OR 1.39; 95% CI 0.87–2.23; p = 0.17), 'ate wild vegetables and fruit' (OR 1.38; 95% CI 0.90–2.10; p = 0.14) and 'ate mushrooms' (OR 0.72; 95% CI 0.38–1.39; p = 0.33).\"\n",
      "source_date": "2017-08-01",
      "source_accessed": "2026-05-01",
      "archive_url": "http://web.archive.org/web/20260503084420/https://pmc.ncbi.nlm.nih.gov/articles/PMC5531747/",
      "calculation_notes": "Documents the epidemiological evidence (or lack thereof) for the berry transmission pathway. Non-significant ORs for berry and wild-produce consumption mean the published literature does not establish berries as a statistically confirmed transmission route. Strong risk factors (dog that hunts game, farmer status) are behaviorally distinct from foraging. Used to frame the gap between the popular fear narrative and the case-control evidence.\n",
      "independence_note": "Systematic review pooling multiple European case-control studies — captures the dominant epidemiological evidence base for AE risk factors.\n"
    },
    {
      "url": "https://www.sciencedirect.com/science/article/abs/pii/S147330992500283X",
      "title": "Unveiling the incidences and trends of alveolar echinococcosis in Europe: a systematic review from the KNOW-PATH project",
      "publisher": "The Lancet Infectious Diseases",
      "source_type": "peer_reviewed",
      "statistic": "Mean European AE incidence 1997–2023: 0.063 per 100,000; 4,207 cases documented; Germany, France, Austria, Switzerland = 68% of total",
      "excerpt": "\"The mean annual incidence from 1997 to 2023 throughout Europe was 0.063 cases per 100,000 people. Historically endemic Austria, France, Germany, and Switzerland accounted for 2,864 (68.08%) of 4,207 cases documented in Europe.\"\n",
      "source_date": "2025-05-01",
      "source_accessed": "2026-05-01",
      "archive_url": "http://web.archive.org/web/20250805154821/https://www.sciencedirect.com/science/article/abs/pii/S147330992500283X",
      "calculation_notes": "Provides the EU-wide mean annual incidence used as the lower bound of the uncertainty range. 0.063/100,000 = 6.3 × 10^-7 per year. Lifetime over 59y: 1 − (1 − 0.00000063)^59 ≈ 3.72 × 10^-5, i.e. ~1 in 26,900. Also confirms the 2025 state of European surveillance and the ongoing rising trend.\n",
      "independence_note": "Independent systematic review from the KNOW-PATH project; uses ECDC TESSy surveillance data and national registries rather than single-center data.\n"
    },
    {
      "url": "https://pmc.ncbi.nlm.nih.gov/articles/PMC12052437/",
      "title": "Presence of Echinococcus eggs in the environment and food: a review of current data and future prospects",
      "publisher": "Parasitology (Cambridge University Press)",
      "source_type": "peer_reviewed",
      "statistic": "E. multilocularis DNA detected in 5.4% of strawberries and 7.3% of blueberries in European endemic countries (seven-country study); viability of those eggs explicitly unknown.\n",
      "excerpt": "\"E. multilocularis DNA was detected in 1.2% of lettuces, 5.4% of strawberries, and 7.3% of blueberries in European endemic countries… although eggs are assumed to be the source of the DNA detected in these studies, the viability of such eggs is unknown.\"\n",
      "source_date": "2025-04-01",
      "source_accessed": "2026-05-01",
      "archive_url": "http://web.archive.org/web/20260525101133/https://pmc.ncbi.nlm.nih.gov/articles/PMC12052437/",
      "calculation_notes": "Documents the molecular evidence for berry contamination while underscoring the key limitation: DNA detection ≠ viable infectious eggs. Used to characterise the contamination pathway that underlies public concern, not to derive a probability estimate. Supports the framing that wild berries are a plausible but unconfirmed dominant transmission route.\n",
      "independence_note": "Independent review of environmental contamination literature; distinct from the epidemiological case-control literature cited above.\n"
    }
  ],
  "comparison_anchors": [
    {
      "label": "Fatal anaphylaxis from bee/wasp sting (lifetime, US adult)",
      "lifetime_us_adult": 0.0001267
    },
    {
      "label": "Death by lightning strike (lifetime, US)",
      "lifetime_us_adult": 0.00000354
    },
    {
      "label": "Death in a plane crash (lifetime, US adult)",
      "lifetime_us_adult": 0.000017
    }
  ],
  "personal_factor_multipliers": [
    {
      "factor": "Residence in high-incidence endemic region (e.g. Doubs/France, Swiss Jura)",
      "multiplier": 10,
      "notes": "AE incidence varies more than an order of magnitude across Europe. The Doubs département (France) and Swiss Jura regularly record 1.0–1.4 cases per 100,000 per year, vs the EU mean of 0.063/100,000. Living in the highest-incidence European zones implies roughly 10–20× the average EU risk. Source: Graeter et al., Infection 2020; KNOW-PATH systematic review, Lancet Infectious Diseases 2025."
    },
    {
      "factor": "Occupational exposure (trapper, hunter, forestry worker in endemic zone)",
      "multiplier": 5,
      "notes": "Case-control studies identify agricultural work and hunting dog ownership as statistically robust AE risk factors. Trappers and hunters have frequent contact with fox carcasses and habitat, substantially elevating exposure to E. multilocularis eggs. Eckert & Deplazes (2004) estimated a ~5× occupational risk elevation for animal handlers and hunters in endemic areas. Source: Eckert J & Deplazes P, Clin Microbiol Rev 2004; Piarroux et al., PLOS NTD 2017 (meta-analysis)."
    },
    {
      "factor": "Dog ownership (dog roams freely or hunts in endemic area)",
      "multiplier": 4,
      "notes": "Owning a dog that hunts or roams outdoors in an endemic region is one of the most consistently replicated AE risk factors across European case-control studies. Dogs can act as transport hosts, depositing E. multilocularis eggs shed from foxes onto domestic surfaces. Pooled OR from the Piarroux 2017 meta-analysis for 'dog that kills game': ~18 (95% CI 3.8–83), the strongest individual risk factor. Source: Piarroux et al., PLOS NTD 2017."
    },
    {
      "factor": "Immunocompromised status",
      "multiplier": 3,
      "notes": "Immunocompromised patients (transplant recipients, those on long-term corticosteroids, HIV-positive with low CD4 counts) experience faster and more aggressive alveolar echinococcosis progression. While baseline incidence is not higher, once infected the subclinical-to-symptomatic conversion is accelerated. WHO/OIE guidelines flag immunosuppression as a major modifier of disease course and outcomes. Source: WHO Informal Working Group on Echinococcosis (WHO-IWGE), WHO Technical Report Series 2003; Brunetti E et al., Acta Tropica 2010."
    }
  ],
  "myth_framing": "overrated",
  "outcome_severity": "fatal",
  "exposure_pattern": "cumulative",
  "outcome_type": "death",
  "valence": "negative",
  "caveats": "This entry normalizes to an adult in an actively endemic European region (southwest Germany, 2012–2019). The figure is not a US adult baseline — Echinococcus multilocularis has a restricted US range, human cases are not nationally reportable, and no reliable US incidence series exists. The number also does not distinguish the berry pathway from other routes: case-control meta-analyses find dog ownership and farming to be the statistically robust risk factors, while berry consumption carries a non-significant pooled OR of ~1.4. No_reliable_estimate is set to false because regional European incidence is well-documented — but the fraction attributable specifically to wild berry ingestion cannot be isolated from published data.\n",
  "quality_score": {
    "d1": 4,
    "d2": 5,
    "d3": 5,
    "d4": 5,
    "d5": 5,
    "d6": 5,
    "d7": 5,
    "d8": 5,
    "avg": 4.875,
    "scored_by": "extracted-from-transcript",
    "scored_at": "2026-05-03",
    "methodology_version": "1.0"
  },
  "reviewer": "quality-review-agent-2026-05-03",
  "last_reviewed": "2026-05-03",
  "reviewed": true,
  "generated_at": "2026-05-01",
  "image": {
    "alt": "A cluster of wild blueberries on low-growing stems against a muted forest floor, flat vector illustration."
  },
  "attribution": "Likelier — https://likelier.app",
  "license": "https://creativecommons.org/licenses/by-sa/4.0/",
  "support": "https://buymeacoffee.com/kgluszczyk?via=likelier&utm_content=api-fear-single",
  "canonical_url": "https://likelier.app/wild-berry-fox-tapeworm"
}