An outbreak of Adenovirus type 8 Keratoconjunctivitis in a nursing home in Madrid

Abstract

This work describes and analyses an outbreak of epidemic keratoconjunctivitis which occurred in 2001 and 2002 in a nursing home for the elderly in Leganes (an area of Madrid). This is the first such published case in Spain with these characteristics and this serotype identification. Sociodemographic characteristics, epidemic curve and attack rates are described. Comparisons of the data were carried out using a chi2 test for qualitative variable and t-test for quantitative. Factors associated with the illness are explored by means of contingency tables and logistic regression models. One hundred and two cases were detected, with an attack rate of 36.4% for residents, and 12.9% for workers, not considering spatial or professional differences. The epidemic curve showed an interpersonal transmission pattern. Multivariate analysis identified the following risk factors in the residents: able to wander freely through the building, urinary incontinence and use of shared bathroom. In 34.6% of the conjunctival samples, adenovirus serotype 8 was detected with identical genomic sequence. Establishment of hygienic sanitary guidance adapted for the cleaning of such establishments and contact with residents as well as early diagnosis and good coordination of human and material resources are key factors in the prevention and control of these outbreaks in closed communities.

Adenovirus Transmission in a Nursing Home: Analysis of an Epidemic Outbreak of Keratoconjunctivitis

“…This outbreak lasted longer (12 weeks) than other reported outbreaks in similar environments (8-9 weeks) [3,8,9] . However, only 6 cases were detected in the last 40 days.…”

“…A possible interpretation is that early adoption of strict hygiene measures contributes to a lower number of cases. In fact, in this outbreak the infection rate was lower as compared to other outbreaks where infection control measures were taken later [9] . Most workers changed their places of work (different corridors and even different floors) for organizational reasons during the time of the outbreak, which may have contributed to the spread of the outbreak.…”

“…However, only 6 cases were detected in the last 40 days. In addition, a lower infection rate was seen in residents (30%) compared with other outbreaks -36% [9] or up to approximately 50% [3,8] . A greater involvement was seen in the area (floor and corridor) where the initial cases occurred.…”

“…Adenovirus serotype 8 is a common cause of EKC outbreaks in different types of closed communities [5,8,9] , and also of large community outbreaks [4,16,17] . The contamination source of the index case was not identified in this outbreak (he had not previously attended an ophthalmological office and no other previous cases were detected).…”

“…The special conditions of care centers for either elderly or chronic patients make them also suitable places for transmission of this disease [3,8,9] . The hands of healthcare staff, medical devices and different products contaminated by adenoviruses [5,7,[10][11][12] are com-mon vehicles of infection within these environments.…”