Biomarkers of experimental Toxocara canis infection are context-dependent: A systematic review of murine models.
Abstract
Background
Toxocara canis infection is a neglected zoonosis associated with multisystemic involvement and persistent larval infection. Murine models are widely used to investigate host-parasite interactions, but methodological heterogeneity limits biomarker comparison and validation.
Objective
To characterize experimental murine T. canis infection models and synthesize parasitological, pathological, immunological, molecular, and functional biomarkers and outcomes.
Methods
PubMed/MEDLINE, Embase, Scopus, Web of Science Core Collection, and Virtual Health Library were searched from inception to September 1, 2026, without publication-date restrictions. Only English-language articles were eligible. Studies were screened using Rayyan and assessed according to a PECOS framework. Risk of bias and methodological quality were evaluated using SYRCLE and an adapted CAMARADES checklist. Findings were synthesized descriptively.
Results
Sixty-seven studies were included. The central nervous system was most investigated (39/67; 58.2%), followed by pulmonary (32/67; 47.8%) and hepatic (24/67; 35.8%) compartments. Larval recovery and tissue PCR characterized parasite localization or persistence, whereas serological, inflammatory, histopathological, molecular, and functional outcomes captured distinct dimensions of infection. Type-2-associated responses, particularly eosinophilia and IL-4, IL-5, and IL-13, were recurrent. Recent studies incorporated transcriptomics, lipidomics, extracellular-vesicle miRNAs, single-nucleus RNA sequencing, and spatial transcriptomics. Methodological limitations were particularly evident in randomization, blinding, and sample-size reporting.
Conclusions
Murine T. canis infection is a dynamic, multisystem process in which biomarker interpretation depends on tissue, timing, and biological context. Evidence supports complementary, purpose-driven outcome assessment rather than a single biomarker or universal protocol. Greater methodological standardization, longitudinal assessment, and multimodal designs may improve reproducibility and biomarker validation.