証拠の質 4.63/5
8次元のレビュー評価。基準は 品質ルーブリック 。各次元は1〜5で評価。
- D1 出典への根拠
- 4/5
- D2 出典の権威性
- 5/5
- D3 算術
- 4/5
- D4 不確実性
- 4/5
- D5 範囲
- 5/5
- D6 文章
- 5/5
- D7 認識の誠実性
- 5/5
- D8 注意事項の完全性
- 5/5
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- あなたの要因
≈ 同じくらいの確率
認知リスク
ペットの寄生虫に対する不安は二つの陣営に分かれる傾向がある。初めて親になった人は、犬や猫が回虫や鉤虫を宿していることを知り、家庭のペットが歩く生物学的危険物だと結論づける。一方、長年のペット飼い主は、このカテゴリー全体を獣医による過剰販売として一蹴する。どちらの陣営も実際の数字を明確に把握していない。関係する病気(トキソカラ症、トキソプラズマ症、皮膚幼虫移行症)は、集団レベルの血清学では実際に一般的だが、免疫機能が正常な成人で劇的な臨床疾患を引き起こすことは稀であり、それが世間の注目を集めない理由の一つである。CDCはトキソカラ症を米国における五つの顧みられない寄生虫感染症の一つに分類しており、この呼称は定義上「広範」と「認識不足」の両方を意味する。
概算: ペット飼い主は約0%か約20%のどちらかを推測しがちだが、真実はその中間にある
出典: 編集部の直感(調査に基づかない)
実際のリスク
米国の6歳以上の人におけるトキソカラ属の血清有病率は約5.1%(NHANES 2011–2014)
6歳以上の米国居住者、全国代表サンプル(NHANES 2011–2014)
計算を表示
NHANES 2011–2014のトキソカラ抗体の横断的血清有病率5.1%は、生涯曝露の推定値として直接使用されている。トキソカラに対するIgG抗体は数年間持続し、集団代表サンプルでの陽性結果は、調査された年齢分布を通じた累積的な生涯曝露に近似するためである。これは保守的な下限値である。NHANES III(1988–1994)は古い検査法を用いて13.9%の血清有病率を見出し、貧困線以下で暮らすサブグループでは10.2%を示している。この数字はトキソカラのみを捕捉している。トキソプラズマ症(血清有病率約9–11%、NHANES 1999–2004)と動物由来の鉤虫(皮膚幼虫移行症、信頼できる全国血清有病率なし)を加えれば、ペット由来の動物寄生虫の生涯曝露率の合計は大幅に上昇するが、トキソカラは最もよく測定されているペット固有の寄生虫であり、見出しとして使用されている。血清陽性の人全員が臨床疾患を有していたわけではなく、感染の大半は不顕性である。
関連するリスク
似たテーマの他のリスク — 関連する不安を探るために。
比較対象を選択
About one in twenty Americans carries antibodies to Toxocara, the roundworm genus shed by dogs and cats, according to the most recent nationally representative serology (NHANES 2011–2014). An older survey cycle put the figure closer to one in seven. Either way, this is not a rare tropical curiosity — CDC ranks toxocariasis among the five neglected parasitic infections it has prioritised for public-health action inside US borders. The parasite’s trick is that most infections are subclinical: larvae migrate through tissue, the immune system walls them off, and the host never knows. The minority who do develop symptoms get visceral larva migrans (fever, wheezing, hepatomegaly) or, more worryingly, ocular larva migrans, which can cause permanent vision loss in a single eye. Children who eat dirt in yards frequented by undewormed dogs are the classic presentation, but the serology makes clear that adults are not exempt.
Toxocara is only the headliner. Toxoplasma gondii, the cat-litter parasite, shows up in roughly 9-11% of the US population by serology (down from 22.5% in the early 1990s), though its transmission routes include undercooked meat, making it harder to pin entirely on the household cat. Zoonotic hookworm (Ancylostoma spp.) causes cutaneous larva migrans — the creeping eruption familiar to anyone who has walked barefoot on a warm beach used by free-roaming dogs — but lacks a reliable national seroprevalence figure. Stack these together and the lifetime probability that a US adult has been parasitised by something their pet (or someone else’s pet) shed into the environment is comfortably higher than most people guess. The word “neglected” in CDC’s classification is doing real epidemiological work: these infections are common precisely because almost nobody thinks about them.
The good news, such as it is, sits in the veterinary aisle. Regular deworming of dogs and cats with broad-spectrum anthelmintics slashes the environmental egg burden, and the secular decline in Toxocara seroprevalence between NHANES III and the 2011–2014 cycle likely reflects rising rates of routine pet healthcare. The bad news is that Toxocara eggs are extraordinarily durable — viable in soil for years — so the neighbourhood’s collective deworming habits matter more than any individual pet owner’s diligence. Poverty is the single strongest risk factor in the NHANES data (10.2% seroprevalence below the poverty line vs 3.9% above it), a pattern that tracks with less access to veterinary care, higher stray-animal density, and more childhood soil contact. The parasite, in other words, is less a household-pet problem than a public-infrastructure problem wearing a household-pet disguise.
関連する豆知識
ペット由来の回虫を保有する生涯確率はおよそ~1 in 20 lifetimeです(米国成人、トキソカラの血清陽性率)。NHANES 2011-2014では、6歳以上の米国の人々におけるトキソカラ属の血清陽性率は~5.1%でした。
根拠台帳
以下の各数値は各出典が報告した内容であり、引用した原文の抜粋と算出方法を記載しています。リンクをクリックして直接確認できます。
1/3 件の出典が引用元と一字一句一致することを独立して検証済み
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[1] Clinical Infectious Diseases (Oxford Academic) — Seroprevalence of Antibodies to Toxocara Species in the United States and Associated Risk Factors, 2011–2014
Seroprevalence of Antibodies to Toxocara Species in the United States and Associated Risk Factors, 2011–2014- 統計値
Overall Toxocara seroprevalence 5.0% (95% CI 4.1–6.1%) among US persons aged ≥6 years in NHANES 2011–2014; males 6.2%, females 3.8%; persons living below poverty threshold 10.2%- 抜粋
“"The overall seroprevalence of Toxocara antibodies was 5.0% (95% CI, 4.1%–6.1%). Seroprevalence was higher in males (6.2%) than in females (3.8%) and was significantly associated with poverty, lower educational attainment, and non-Hispanic black race/ethnicity." ”
- 出典データ
- 2018-01-15
- アクセス日
- 2026-04-26 · アーカイブ版
- 計算過程
- Liu et al. (2018) is the primary NHANES 2011–2014 analysis. The 5.0% figure (rounded to 5.1% in the companion Farmer et al. paper using a slightly different age cutoff) is used as the native seroprevalence. Because Toxocara IgG persists for years post-infection, the cross-sectional seroprevalence in a nationally representative age-distributed sample approximates cumulative lifetime exposure. The poverty-line subgroup (10.2%) and NHANES III historical figure (13.9%) set the uncertainty high bound at 0.14; the low bound (0.03) reflects the seroprevalence in non-Hispanic white adults above the poverty line.
- 独立性
- Liu et al. is an independent academic analysis of NHANES sera, not authored by CDC staff. Uses the same serum bank as Farmer et al. but different statistical methods and age stratification.
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[2] US Centers for Disease Control and Prevention (CDC) — About Toxocariasis
About Toxocariasis- 統計値
CDC classifies toxocariasis as a neglected parasitic infection; many infected people are asymptomatic but the disease can cause organ and eye damage- 抜粋
“"Toxocariasis is an infection caused by the parasite Toxocara. It spreads to people from animals, usually dogs or cats. … Many people who are infected don't have any symptoms. … Toxocariasis is considered a Neglected Parasitic Infection, one of a group of diseases that results in significant illness among those who are infected." ”
- 出典データ
- 2024-09-10
- アクセス日
- 2026-04-26 · アーカイブ版
- 計算過程
- The CDC page was updated and no longer contains the ~14% prevalence figure that previously appeared (derived from NHANES III 1988–1994). The current page focuses on disease description, transmission, and classification as a neglected parasitic infection. The ~14% historical seroprevalence from NHANES III is still cited in the academic literature (e.g., Liu et al. 2018, source 1 above) and is used to set the uncertainty high bound at 0.14. CDC's classification of toxocariasis as a neglected parasitic infection establishes that this is a recognised public-health concern, not a fringe worry.
- 独立性
- CDC public-health summary page, editorially independent of the Liu et al. academic analysis.
-
[3] American Journal of Tropical Medicine and Hygiene (PMC) — Neglected Parasitic Infections in the United States: Toxoplasmosis 検証済み
Neglected Parasitic Infections in the United States: ToxoplasmosisSee all 2 Likelier entries citing this source →
- 統計値
US T. gondii seroprevalence declined from 22.5% (NHANES III, 1988-1994) to ~9.0% (NHANES 1999-2004) in persons 12-49 years- 抜粋
“"The age-adjusted T. gondii antibody seroprevalence was 22.5%, but there was considerable variation by region; the lowest age-adjusted T. gondii seroprevalence was among persons residing in the western region of the United States (17.5%) and highest in the Northeast (29.2%). … A study comparing the population-based National Health and Nutrition Examination Survey (NHANES) during 1988–1994 with the NHANES during 1999–2004 showed a 36% decrease in the age-adjusted seroprevalence in the more recent study (14.1% to 9.0% in persons 12–49 years of age)." ”
- 出典データ
- 2014-05-07
- アクセス日
- 2026-04-26 · アーカイブ版
- 検証
- グラウンディング監査の際、抜粋を引用元から独立して再取得し、原文と一字一句一致することを確認しました。
- 計算過程
- Jones et al. (2014) report a decline from 22.5% (NHANES III) to ~9.0% (NHANES 1999-2004) in the 12-49 age band. The previously cited "12.4%" and "9.1%" figures do not appear in this article and were fabricated. The ~9-11% range for recent seroprevalence is used as context for the broader pet-zoonotic-parasite picture. Toxoplasma gondii is primarily cat-associated (oocyst shedding in cat faeces, contaminated soil/litter). Combined with Toxocara (5%), the two parasites alone indicate that a substantial fraction of US adults have serological evidence of pet-related parasite exposure. Toxoplasmosis is not used in the headline figure because transmission routes include undercooked meat, making it harder to attribute solely to pet ownership.
- 独立性
- Jones et al. (2014) is an independent academic review of NHANES toxoplasmosis data, separate from the Toxocara analyses and the CDC toxocariasis page.







