SCENARIO
Introduction
In May 2018, two outbreaks of conjunctivitis occurred in quick succession at two nearby boarding schools. School A had 559 students and teachers and School B had 784 students and teachers. The students lived in dormitory rooms housing approximately 10 students in each room. Students would live in those rooms during the week while not in class, and all students returned home each weekend. While staying at the schools, each student had their own towels and toiletries. Students shared common restroom facilities, which included sinks, toilets, showers, and drying racks.
Disease description
Conjunctivitis can be caused by one of several viruses or bacteria. Conjunctivitis can be very contagious and has multiple avenues of transmission from person to person. Transmission of the virus or bacteria occurs when an infected individual touches an infected eye and then touches another surface. A second individual touching that same surface may become infected if they subsequently touch their own eye. The viruses or bacteria that cause conjunctivitis can survive for several weeks, and many are resistant to disinfectants.
Signs and symptoms
Redness, swelling, blurring, pain, itching, tearing, and/or discharge of one or both eyes
Outbreak Data
Variables School A School B
Number of staff/students 559 784
Number of staff cases 1 1
Number of student cases 170 159
Average number of cases per classroom 14.17 8.32
Date of first recorded case May 18 May 23
Date of last recorded case July 10 July 6
Outbreak duration (days) 54 45
Number of cases (% of staff/students) 171 (30.6%) 160 (20.4%)
Total number of male cases (% of male population) 89 (52.0%) 117 (73.1%)
Total number of female cases (% of female population) 82 (48.0%) 43 (26.9%)
Disease transmission factors
Based on interviews with 156 students, several common transmission factors were discovered. Patients who became infected with conjunctivitis had come into contact with the hands, eye drops, soap, and bedding of already infected patients. In addition, transmission was also found to have occurred from a family member that did not attend either school.
Previous outbreaks of conjunctivitis have shown that strict hand washing, instrument disinfection, and enhanced waste disposal procedures were not sufficient to prevent the further proliferation of an outbreak.
Decisions made
The students who were identified as the index patient for each school were isolated from each school for 7–10 days following their initial diagnosis of conjunctivitis. Those students returned to their schools following the isolation period.
REQUIREMENTS
Submission cannot contain more than a 10% match to any one individual source.
Note: All references used should be current, within the last five years.
TASK INSTRUCTIONS:
Understanding Risk Factors
A. Based on the given scenario, identify two risk factors that may have contributed to the spread of conjunctivitis either within each school or between both schools.
B. Explain, in detail, how each identified risk factor may have contributed to the transmission of conjunctivitis from person to person.
C. Describe, in detail, two potential actions that the schools, families, or communities could have taken to mitigate the effects of the identified risk factors.
Evidence Collection
D. Based on the given scenario, identify two additional pieces of evidence or sources of data that epidemiologists should have collected and used to better understand the origin, transmission, or characteristics of this outbreak.
E. Explain how each piece of evidence or source of data would improve epidemiologists’ understanding of this outbreak.
Analyzing Outbreak Patterns
F. Based on the given scenario, identify two patterns in the data that demonstrate a difference in the characteristics or transmission of the conjunctivitis outbreak at each school.
G. For each identified pattern, provide a potential explanation for why that difference is present at each school.
H. Explain, in detail, whether the decision to isolate the initial cases at home for 7–10 days following a diagnosis of conjunctivitis was effective in limiting the spread of the outbreak.
I. Acknowledge sources, using in-text citations and references, for content that is quoted, paraphrased, or summarized.
J. Demonstrate professional communication in the content and presentation of your submission.
