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A pig model of Acanthamoeba keratitis: transmission via contaminated contact lenses
Y G He1, J P McCulley, H Alizadeh
1Department of Ophthalmology, University of Texas Southwestern Medical Center, Dallas 75235.
Abstract:
A model of contact lens-induced Acanthamoeba keratitis was developed in Yucatan micropigs. Pigs fitted with parasite-laden soft contact lenses developed corneal infections that clinically and histopathologically mimicked the human counterpart. Three distinct stages of disease became apparent and were categorized as: acute, condensed infiltrate, and resolution stages. Viable parasites were isolated from corneal scrapings and smears were taken during the acute and condensed infiltrate stages. In addition, cysts could be identified deep within the stroma of histological specimens taken during the resolution stages. The characteristic dense, white ring-like infiltrates, stroma edema, keratic precipitates, and the chronic nature of the infections were similar to those observed in human Acanthamoeba keratitis. Histopathological examination of infected corneas revealed extensive neutrophilic infiltrates, stromal necrosis, and disorganization of the collagen lamellae. The strong correlation between the clinical and histopathologic features of contact lens-induced Acanthamoeba keratitis in the pig as well as the anatomical similarity of the pig eye with the human eye make the porcine model a valuable tool for investigations of the immunology, cell biology, and therapy for Acanthamoeba keratitis.
Insights
A new Yucatan micropig model effectively mimics human Acanthamoeba keratitis caused by contact lens wear. This model shows distinct disease stages and is valuable for studying infections and developing therapies.
Area of Science:
- Ophthalmology
- Infectious Diseases
- Veterinary Medicine
Background:
- Acanthamoeba keratitis (AK) is a severe corneal infection often linked to contact lens wear.
- Existing animal models may not fully replicate the clinical and pathological features of human AK.
Purpose of the Study:
- To develop and characterize a Yucatan micropig model of contact lens-induced Acanthamoeba keratitis.
- To assess the model's clinical and histopathological relevance to human AK.
Main Methods:
- Yucatan micropigs were fitted with soft contact lenses contaminated with Acanthamoeba parasites.
- Corneal infections were monitored clinically, and samples were collected for parasite isolation and histopathological analysis.
- Disease progression was categorized into acute, condensed infiltrate, and resolution stages.
Main Results:
- The porcine model exhibited clinical signs and histopathological features closely resembling human AK, including ring infiltrates, edema, and stromal necrosis.
- Viable Acanthamoeba parasites and cysts were identified in corneal tissues throughout different disease stages.
- The pig eye's anatomical similarity to the human eye was confirmed.
Conclusions:
- The Yucatan micropig model provides a robust and relevant platform for studying Acanthamoeba keratitis.
- This model is suitable for investigating the immunology, cell biology, and therapeutic strategies for AK.
- The model's correlation with human disease enhances its value for preclinical research.