Migration Pattern and Tissue Tropism of Toxascaris leonina (Linstow, 1902) Larvae: An in vivo Evaluation

Authors
Mohammad Sardari 1
Alireza Nourian 2
Farzad Parsa 3
Salman Zafari 4
Heshmatollah Taherkhani 5
Amirhossein Maghsood 1
Mohammad Matini 1
Seyed Mousa Motevali Haghi 1
Mohammad Fallah 1
1 Department of Medical Parasitology and Mycology, School of Medicine, Hamadan University of Medical Sciences, Hamadan, Iran
2 Department of Pathobiology, Faculty of Veterinary Science, Bu-Ali Sina University, Hamedan, Iran
3 Department of Medical Laboratory Sciences, Borujerd Branch, Islamic Azad University, Borujerd, Iran
4 Department of Medical Parasitology and Mycology, School of Public Health, Tehran University of Medical Science, Tehran, Iran
5 Department of Medical Laboratory Sciences, Faculty of Paramedical Sciences, Islamic Azad University, Tehran, Iran
10.61882/ibj.4998
Abstract
Background: The role of Toxascaris leonina in visceral larva migrans is controversial. This study aimed to investigate the migratory behavior of T. leonina larvae across different organs in mice.

Methods: Six-week-old Swiss albino mice (n = 26) were randomly allocated into six experimental groups and one control group. Each mouse in the experimental groups was orally inoculated with 1,000 embryonated T. leonina eggs. The animals were euthanized at 2, 5, 10, 15, 20 and 30 dpi (days post-infection). Tissue samples were examined for larval presence and associated pathological changes using digestive and histopathological methods. The squash method was used for brain tissue analysis.

Results: T. leonina larvae were recovered from the small intestinal wall, lungs, liver, and striated muscles. No larvae were detected in the kidneys, heart, spleen, and brain using digestive or squash methods. Histological examination revealed granulomatous reactions, inflammatory cell accumulation, and larval presence in the isolated tissues. Larval concentration in the striated muscles increased over time, demonstrating the potential of Swiss albino mice to serve as paratenic hosts in toxocariasis.

Conclusion: Our study exhibits that Swiss albino mice are susceptible to T. leonina infection, with larvae localizing primarily in the small intestinal wall, liver, lungs, and striated muscles.
Keywords
Larva migrans
Toxocariasis
Tropism
Iranian Biomedical Journal
Volume 29, Issue 3 - Serial Number 118
May and June 2025
Pages 167-172