Burden of Mycotic Keratitis in West Africa
Harish C Gugnani*
Professor of Medical Mycology (retired), Department of Microbiology, Vallabhbhai Patel Chest Institute, University of Delhi, India
*Corresponding Author: Harish C Gugnani, PhD., FRC. Path. (Lond.), Professor of Medical Mycology (retired), Department of Microbiology, Vallabhbhai Patel Chest Institute, University of Delhi, India.
Published: January 24, 2024
Abstract
Mycotic or fungal keratitis (FK) is a sight-threatening disease, caused by infection of the cornea by filamentous fungi or yeasts. In tropical, low and middle-income countries, it accounts for the majority of cases of microbial keratitis (MK). Filamentous fungi, in particular Fusarium spp., the aspergilli and dematiaceous fungi, are responsible for the greatest burden of disease (Hoffman et al 2021). The predominant risk factor for filamentous fungal keratitis is trauma, typically with organic, plant-based material. In developed countries, contact lens wear and related products are frequently implicated as risk factors, and have been linked to global outbreaks of Fusarium keratitis in the recent past. In 2020, the incidence of FK was estimated to be over 1 million cases per year, and there is significant geographical variation: accounting for less than 1% of cases of MK in some European countries to over 80% in parts of south and south-east Asia (Hoffman et al 2021). The proportion of MK cases is inversely correlated to distance from the equator and there is emerging evidence that the incidence of FK may be increasing. Diagnosing FK is challenging; accurate diagnosis relies on reliable microscopy and culture, aided by adjunctive tools such as in vivo confocal microscopy or PCR. Unfortunately, these facilities are infrequently available in areas most in need. Current topical antifungals are not very effective; infections can progress despite prompt treatment. Antifungal drops are often unavailable. When available, natamycin is usually first-line treatment. However, infections may progress to perforation in ~25% of cases (Hoffman et al 2021). Mycotic keratitis refers is most common in tropical and subtropical locations. The annual global incidence of fungal keratitis (based on culture-positive cases) is estimated 1,051,800 (736,250-1,367,300) cases. The highest estimated incidences are in Asia and Africa, and the lowest in Europe. Over million cases of mycotic keratitis occur globally every year (Brwon et al 2020). Over 100 species have been known to be causal agents, and novel pathogens are regularly added: however. the common causative agents are Fusarium spp., Aspergillus flavus, and A. fumigatus and Candida albicans. (GAFFI-Fungal keratitis Fact sheet by David W Denning).
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