Kaweesi Calvin Nantalaga, Alice Nantege, Martha Nabirye
Respiratory findings were reported in a substantial share of published cases, spanning imaging abnormalities to eosinophilic lung disease; eosinophilia was frequent but not universal. Because the evidence comprises largely case reports from a respiratory-focused search, these proportions describe what has been reported rather than true frequency. Prospective studies in endemic, resource-limited settings are needed.
BACKGROUND: Human toxocariasis is among the most common helminthic zoonoses worldwide, and larvae traverse the lungs during visceral migration. Respiratory morbidity among diagnosed patients remains poorly characterised, in contrast to the much larger seroepidemiological literature linking Toxocara seropositivity to asthma.
OBJECTIVES: To map the reported occurrence and clinical spectrum of respiratory disease in confirmed or probable human toxocariasis, and to identify evidence gaps.
ELIGIBILITY CRITERIA: Case reports, case series, cross-sectional studies, cohorts and trials reporting a respiratory outcome in confirmed or probable toxocariasis. Seroepidemiological association studies, non-Toxocara larva migrans and reports lacking patient-level respiratory data were excluded.
SOURCES OF EVIDENCE: MEDLINE (via PubMed) and the Web of Science Core Collection, from database inception to 13 June 2026.
CHARTING METHODS: Two reviewers independently screened and charted data, with disagreements resolved by a third. Findings are presented descriptively, without critical appraisal or meta-analysis.
RESULTS: Sixty-five studies reporting 989 patients were included, published 1980 to 2026. Case reports predominated (46/65; 70.8%) and only 1/65 (1.5%) originated from sub-Saharan Africa. Any respiratory symptom was documented in 32/46 case reports (69.6%). Across 12 studies of other designs (593 patients), study-level prevalence ranged from 0.0% to 80.7%, and from 0.0% to 66.7% excluding one cohort reporting a non-disaggregable pooled figure. Imaging was reported in 53/65 studies (81.5%), most often nodules (22/53; 41.5%), interstitial infiltrates (16/53; 30.2%) and ground-glass opacity (14/53; 26.4%). Peripheral eosinophilia was present in 58/65 (89.2%) and explicitly absent in 2/65 (3.1%); lung function was reported in 2/65 (3.1%).
CONCLUSION: Respiratory findings were reported in a substantial share of published cases, spanning imaging abnormalities to eosinophilic lung disease; eosinophilia was frequent but not universal. Because the evidence comprises largely case reports from a respiratory-focused search, these proportions describe what has been reported rather than true frequency. Prospective studies in endemic, resource-limited settings are needed.