Infection mediated ocular surface stress responses are activated as early defense mechanisms in response to host cell damage. Integrated stress responses initiate the host response to different types of infections and modulate the transcription of key genes and translation of proteins. The crosstalk between host and pathogen results in profound alterations in cellular and molecular homeostasis triggering specific stress responses in the infected tissues. The amplitude and variations of such responses are partly responsible for the disease severity and clinical sequelae. Understanding the etiology and pathogenesis of ocular infections is important for early diagnosis and effective treatment.
Ocular Infection |
Causative Agent | Sign/Symptoms | Treatment |
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Bacterial Keratitis |
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Symptoms: Eye pain, blurred vision, photophobia, and discharge Signs: Corneal infiltrate of varying involvement of corneal stromal depth and diameter with overlying epithelial defect. Severe infections can be associated with anterior chamber inflammation and hypopyon formation. Progressive ulceration can result in complications including corneal perforation, scleritis, and endophthalmitis |
Topical antibiotics are used based on microbiological sensitivity. Combination of medications may be required |
Fungal Keratitis |
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Symptoms: Eye pain, blurred vision, photophobia, and discharge Signs: Dry looking base of corneal ulcer base with feathery margins. Can also have satellite lesions, endoexudates and hypopyon |
Topical antifungal medications as per severity of infections. Natamycin and voriconazole are the most common medications used. Oral antifungals of the azole group are also given for more severe infections |
Viral Keratitis |
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Symptoms: Discomfort, watering, itching, burning, and pain in the eye Signs: Would depend on the form of the herpes viral involvement |
Topical acyclovir and ganciclovir for epithelial forms of disease. Stromal viral keratitis requires topical steroids. Viral endothelitis and recurrent stromal involvement require oral antiviral medications |
Bacterial Conjunctivitis |
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Symptoms: Unilateral or bilateral redness, classically purulent discharge, photophobia, tearing, irritation, stinging, burning, and discomfort Signs: Diffuse bulbar conjunctival injection. Discharge is initially watery, becomes purulent as infection progresses |
Acute bacterial conjunctivitis is usually treated with topical fluoroquinolones, macrolides, and aminoglycosides. Tetracycline and macrolides are used to treat chlamydia |
Trachoma | Chlamydia trachomatis serotypes A, B, Ba, C |
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SAFE strategy: S: Surgery in case of trichiasis, A: Antibiotics (azithromycin and erythromycin) for C. trachomatis infection, F: Facial cleanliness, E: Environmental change for sanitation |
Viral Conjunctivitis |
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Symptoms: Unilateral or bilateral watering, redness, discomfort, and photophobia Signs: Eyelid edema, follicular conjunctivitis, tender preauricular lymphadenopathy. Chronic cases can have mild conjunctival scarring |
Symptomatic relief and cold compresses. Topical antibiotics to prevent secondary infection and topical steroids for severe inflammation in conjunctivitis |
Ocular Disease | Techniques Used | Host Molecular Responses | References |
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Bacterial keratitis |
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Fungal keratitis |
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Viral keratitis |
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Viral conjunctivitis |
ELISA | Elevated levels of hyaluronic acid (HA) can acts as a rapid diagnostic marker | Dreyfuss, J.L. et al Juliana (2015) |
Ocular Infection | Techniques | Host Molecular Responses | References |
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Viral Keratitis |
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Ebola virus uveitis | RNA sequencing, RT-qPCR | Type I interferon (IFN) | Smith, J. R. et al. (2017) |
Bacterial keratitis |
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Fungal keratitis |
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Acanthameoba keratitis | MIP-2 and myeloperoxidase (MPO) assays | MIP-2 induces neutrophil infiltration which acts as a therapeutic strategy in Acanthameoba keratitis | Hurt, M. et al. (2001) |
This entry is adapted from the peer-reviewed paper 10.3390/ijms23063111