Outbreak of epidemic keratoconjunctivitis caused by human adenovirus serotype 8 in a nursing home

Abstract

Background: Ocular infections caused by human adenovirus are highly contagious and can cause outbreaks, especially in nursing homes. In this work, we describe the epidemiological and analytical research as well as the control measures carried out for a conjunctivitis outbreak. Methods: Descriptive epidemiological study. Cases with a symptom onset date prior to oficial communication were analyzed retrospectively. The rest was analyzed prospectively. Conjunctival smears were collected for microbiological study. Virological analysis was performed by detecting adenovirus by PCR and genotyping. A data questionnaire that collected clinical and epidemiological information was designed. Possible risk factors associated with infection were studied by calculating the Odds Ratio. Results: On June 11, 2019, the Epidemiological Surveillance Section of the Provincial Health Department of Albacete was notified of the existence of a large number of cases of conjunctivitis in a geriatric center. 54 cases were declared: 43 internal residents, 3 day center assistants and 8 workers. Attack rates were 35.8%, 12.5% and 8.4% respectively. Three risk factors were associated with the disease: patient´s lack of autonomy, being a resident at the nursing home and having their room assigned on the first floor. Human adenovirus serotype 8 was detected in the patients’ samples. Conclusions: A high attack rate was observed in internal residents and the disease was associated with patient´s lack of autonomy and having their room assigned on the first floor of the nursing home. The outbreak was caused by human adenovirus serotype 8.