Epidemiology and Aetiological Diagnosis of Corneal Ulceration in Sana’a City, Yemen

Background: Corneal ulcer is an inflammatory or more serious condition of the cornea involving a disorder of the epithelial layer with involvement of the corneal stroma. It is a common condition in humans, especially in the tropics and agricultural communities.

Objectives: To identify epidemiological characteristics and risk factors leading to corneal ulceration in Sana’a, Yemen, and to identify specific pathogenic organisms responsible for infection.

Methods: All patients with suspected infectious central corneal ulceration presenting to the ophthalmic clinics in the main hospitals of Sana’a city, Yemen from 1 January to 31July 2017 were evaluated. The clinical samples culturing, and diagnosis were done at National Center of Public Health laboratories Sana’a (NCPHL). Social, demographic data and information relating to risk factors were recorded, all patients were screened, and corneal scrapes and cultures were performed.

Results: In 7-month period 108 patients with central corneal ulceration were evaluated. The male to female ratio was 3.5:1, and the patient ranged in age from 1 to 80 years. The most common risk factor was trauma in 26.9% of patients, followed by previous eye surgery and previous eye diseases of 5.6%. Other risk factors such as dryness and trauma, facial palsy, previous viral infections, and dryness were less common. Agents responsible for the trauma were mainly vegetable matter (36.4%) followed by blunt trauma (15.2%), while chemical injury was only 6.1% of total trauma. In other hand 42.4% of patients were unknown of the agents responsible for the trauma. Cornea laboratory diagnoses were positive in 77 patients (71.3%), of those individuals with positive cultures 42.6% had pure bacterial infections, 6.5% had pure viral infections, and 5.6% had pure fungal infections. The most common bacterial pathogen isolated was Staphylococcus aurous (41.3% of all positive bacterial cultures), followed by Streptococcus viridians (6.3%), and Staphylococcus epidermidis (6.3%). The most common fungal pathogen isolated was Candida albicans (41.2% of all positive fungal cultures), followed by filamentous fungi (23.6%).

These findings have important public health implications for the treatment and prevention of corneal ulceration in developing countries such as Yemen. Such comprehensive surveys are necessary to assess the specific epidemiological characteristics of corneal ulceration that are unique to each region and population.

Keywords: Epidemiology; Aetiological diagnosis; Corneal ulceration; Yemen