Case report: An outbreak of viral conjunctivitis among the students and staff of visually impaired school, Tamil Nadu, India, 2020

Abstract

Introduction: On February 2, 2020, the head of a visually impaired school notified similar eye symptoms among the students. We investigated the cluster to confirm the diagnosis, identify potential exposures, and propose recommendations.

Methodology: We defined a case as redness/watering/discharge from any eye among the students and staff, January-February 2020. We actively searched for the cases and calculated attack rates. We drew epicurve by date of symptoms onset. We conducted a retrospective cohort study of students and staff. We collected data on potential exposures and calculated Risk Ratio (RR), 95% Confidence Interval (95%CI), and Population Attributable Risk (PAR). We sent a conjunctival swab of the three cases for microbiological analysis.

Results: We diagnosed the cases as acute conjunctivitis and identified 39 (76%) cases among 51 individuals. All the 39 cases reported watering and redness; 28 (72%) and 12 (31%) reported eye pain and discharge, respectively. The median age of the case was 11 years (range: 6-48 years). The attack rate didn't differ significantly between males [77% (20/26)] and females [76% (19/25), p = 0.9]. The attack rate was higher among the students [86%, (38/44)] than staffs [14%, (1/7), p = <0.01]. Contact with a case [RR = 2.5, 95%CI = 1.3-4.8, PAR = 51%] and staying inside campus [RR = 6.0, 95%CI = 1.0-37.3, PAR = 81%] were associated with the acute conjunctivitis outbreak. All the three conjunctival swabs were negative for bacterial growth.

Conclusion: Close contact with the case and staying inside the campus led to the outbreak of acute conjunctivitis among the students and staff of the visually impaired school.

Keywords: India; conjunctivitis; disease outbreak; risk factors; viral conjunctivitis.