Retinochoroiditis is Induced by Oral Administration of Toxoplasma Gondii Cysts in the Hamster Model

Administration of Toxoplasma cysts by intraperitoneal innoculation in the Syrian Golden Hamster provides a reproducible animal model of acquired Toxoplasmic retinochoroiditis and cysts are observed in the brain. However, toxoplasmosis is frequently acquired by oral ingestion of contaminated foodstuffs and it is recognised that the route by which disease is acquired may influence its pathogenesis and clinical expression. This study aimed to determine whether retinochorioiditis and cysts in the brain develop after oral ingestion in the Syrian Golden Hamster model as this is the route of induction akin to that in man and may therefore be more relevant in the study of disease pathogenesis. All animals developed disease by 4 weeks. Ocular and cerebral inflammation was confirmed by histology at 16 weeks and this was milder than in the original model.