An Outbreak of Chikungunya Fever Among Employees of a Large Pediatric Hospital in the Dominican Republic

Background: Chikungunya Fever (CHIK) is an arboviral disease transmitted by the Aedes mosquito. The disease is characterized by fever, rash, arthritis and myalgias. In 2014, there was a large outbreak of CHIK in the Dominican Republic (DR) with more than 500,000 cases reported to the Dominican Ministry of Health. There is little information on CHIK transmission in healthcare facilities. The objective of this study was to characterize a CHIK outbreak among hospital employees at a large teaching hospital.

Methods: This was a cross-sectional analysis and outbreak investigation of CHIK cases among employees of the Robert Reid Cabral Hospital (RRCH) in the DR during the 2014 outbreak. We used the World Health Organization criteria to classify probable cases. We extracted demographic and clinical data from surveillance forms, hospital personnel documents and patient records. We generated descriptive statistics, performed bivariate analysis, and calculated attack rates and measures of association.

Results: A total of 108 employees were diagnosed with CHIK at the RRCH during March-September 2014. Median age of the cohort was 40 years (IQR 31 – 50 years). The majority of patients were female (84.3%). Only one patient was hospitalized. The most frequent clinical manifestations were fever (100%), arthritis/arthralgias (100%), headaches (66%), and rash (65%). The attack rates were higher for physicians in training (12.1%) and hospital cleaning personnel (9.6%) compared to nurses (3.7%), ancillary medical staff (4.5%) and administrative personnel (7.5%). Physicians in training were more likely to be infected when compared to all other hospital staff (OR=2.5, 95% CI 1.4-4.5) and the general population (OR=2.6, 95% CI 1.5-4.3).

Conclusion: To our knowledge, this is the largest case series of CHIK among hospital workers. It is interesting that higher attack rates were observed in employees with longer patient contact hours and broad environmental exposure to inpatient areas. Nosocomial transmission may have occurred in some of these patients given the high density of mosquitoes in our hospital wards during summer months and the lack of air conditioned rooms and bed nets in the inpatient units.