HS340 Unit 6 Outbreak Investigation Writeup Example

Seventeen Wrestlers, One Mat Room: A Unit 6 Outbreak Investigation Writeup of Herpes Gladiatorum on a Composite High School Team

[Student Name]

Purdue University Global

HS340: Epidemiology

Unit 6 Outbreak Investigation Writeup

[Instructor Name]

[Date]

The school, team, wrestlers and counts are composite; the camp outbreak report, the management review and the field manual cited are real.

Notification

On a Monday in January, the athletic trainer at a composite high school called the county health department. Three varsity wrestlers had blistering rashes on the face and neck, and a fourth had a similar rash on his forearm. The team had a dual meet scheduled for Thursday. The trainer asked whether the meet should go ahead.

Background

The team had [64] wrestlers and [2] coaches. Practices ran six days a week in one mat room, with wrestlers paired by weight class for drilling and live wrestling. Mats were cleaned once a day, after the last practice. Two weeks before the call, eight varsity wrestlers had competed in a weekend tournament with teams from four other schools.

Herpes gladiatorum is skin infection with herpes simplex virus type 1 spread by direct skin contact during wrestling. A classic investigation at a high school wrestling camp showed how quickly it spreads through a group whose sport requires prolonged skin contact, and that lesions often appear on the head, neck and arms where opponents' skin touches (Belongia et al., 1991).

Case Definition

Confirmed case: a team member with a vesicular or ulcerative skin lesion beginning on or after the date of the tournament, with herpes simplex virus detected by laboratory testing.

Probable case: a team member with a clustered vesicular rash on the head, neck, trunk or extremities beginning in the same period, examined by the team physician or a health department nurse, without laboratory testing or with testing not yet reported.

The definition included probable cases on purpose. Early lesions can look like impetigo or ringworm, and some wrestlers had already started antiviral medicine from their own doctors before a sample was taken.

Writing the definition to include probable cases traded a little specificity for the ability to see the whole outbreak, which mattered more when the aim was to stop spread on a mat.

Case Finding

A health department nurse and the team physician examined all [64] wrestlers at practice on Tuesday and again each Monday for four weeks. Wrestlers were asked about lesions, fever and swollen glands, and about contact with wrestlers from other teams. The trainer's injury log and the school nurse's visit log were reviewed for skin complaints since the tournament.

Descriptive Epidemiology

Seventeen wrestlers fit the case definition, giving an attack rate of 26.6 percent; [9] were confirmed by PCR testing, and [8] were probable. No coaches were affected. Lesions were on the head or face in [9] wrestlers, on the arms in [6] and on the trunk in [2]. Five reported fever, and three had eye symptoms and were referred to an ophthalmologist; none had corneal involvement.

The epidemic curve, plotted by date of lesion onset in four-day intervals across 36 days, shows four clusters. The index case, a varsity wrestler who had attended the tournament, developed a facial rash six days after it. A second cluster of [4] cases began about a week later, then a cluster of [8], then a final [4]. Each cluster followed the last by roughly the virus's usual incubation period of several days to two weeks, the pattern of transmission from one wrestler to the next, not exposure to one shared source. A point-source outbreak, such as contaminated equipment used once, would have produced a single peak within one incubation period. Here each peak followed the last, and cases in the later clusters were mostly the practice partners of cases in the earlier ones, which is how the investigation came to look at pairing records at all.

Analytic Comparison

Because practices paired wrestlers by weight class, the investigation compared wrestlers who had drilled or wrestled with a case during that case's infectious period with those who had not. Among [19] practice partners of a case, [11] became cases, 57.9 percent. Among the other [45] wrestlers, [6] became cases, 13.3 percent. The risk ratio is 4.35. The six cases without a known partner link all trained in the same afternoon group as a case and may have had contact during team drills that the pairing records did not capture.

Three wrestlers on an opposing team developed similar lesions after the Thursday dual meet, which went ahead before the extent of the outbreak was known. Their health department was notified.

Control Measures

The health department and the school agreed on five measures, drawing on published guidance for managing outbreaks in wrestling (Anderson, 2008):

1. Any wrestler with a lesion was withheld from practice and competition until lesions had crusted over and the wrestler had taken antiviral treatment for at least five days, as cleared by the team physician.

2. Skin checks by the trainer before every practice for the rest of the season.

3. Mats cleaned between practice groups as well as at the end of the day.

4. Wrestlers told not to share towels, headgear or water bottles.

5. The team withdrew from one weekend tournament while cases were still appearing.

After the measures began, one more cluster of [4] cases occurred, consistent with infections acquired before the measures took effect, and no new cases began after day 36.

Discussion

The pattern of waves, the concentration among practice partners and the lesion sites all point to spread during practice from a virus introduced at the tournament. The partner comparison is the strongest piece of evidence, but it rests on pairing records kept by coaches, and contact outside assigned pairs was common. The investigation could not test whether the index case was infected at the tournament or reactivated a past infection, since no samples were available from other teams' wrestlers at that time.

Two lessons stand out. First, the decision to wrestle the Thursday meet spread the outbreak to another school; the health department now asks schools to hold competition when two or more athletes have new vesicular rashes in a week. Second, daily skin checks found new lesions within a day of onset, earlier than wrestlers reported them, which shortened the time each new case spent on the mat.

Conclusion

This was a person-to-person outbreak of herpes gladiatorum among a high school wrestling team, introduced at a tournament and spread during practice. Exclusion until lesions crusted, skin checks and more frequent mat cleaning ended it within five weeks. The investigation followed the standard steps of field work: confirming the outbreak, defining cases, finding them, describing them by time, place and person, testing a hypothesis and putting control measures in place (Rasmussen & Goodman, 2019).

References

Anderson, B. J. (2008). Managing herpes gladiatorum outbreaks in competitive wrestling. Current Sports Medicine Reports, 7(6), 323-327. https://doi.org/10.1249/JSR.0b013e31818eebde

Belongia, E. A., Goodman, J. L., Holland, E. J., Andres, C. W., Homann, S. R., Mahanti, R. L., Mizener, M. W., Erice, A., & Osterholm, M. T. (1991). An outbreak of herpes gladiatorum at a high-school wrestling camp. New England Journal of Medicine, 325(13), 906-910. https://doi.org/10.1056/NEJM199109263251302

Rasmussen, S. A., & Goodman, R. A. (Eds.). (2019). The CDC field epidemiology manual. Oxford University Press.