Infectious Disease Frequency Among Evacuees at Shelters After the Great Eastern Japan Earthquake and Tsunami: A Retrospective Study

OBJECTIVE: After the Great Eastern Japan Earthquake and tsunami, the World Health Organization cautioned that evacuees at shelters would be at increased risk of infectious disease transmission; however, the frequency that occurred in this population was not known. METHODS: We reviewed medical charts of evacuees who visited medical clinics at 6 shelters from March 19, to April 8, 2011. Excluded were patients who did not reside within the shelters or whose medical records lacked a name or date. We investigated the frequency of and cumulative incidences of acute respiratory infection [ARI], acute gastroenteritis, acute jaundice syndrome, scabies, measles, pertussis, and tetanus. RESULTS: Of 1364 patients who visited 6 shelter clinics, 1167 patients (86.1%) were eligible for the study. The median total number of evacuees was 2545 (interquartile range [IQR], 2277-3009). ARI was the most common infectious disease; the median number of patients with ARI was 168.8 per week per 1000 evacuees (IQR, 64.5-186.1). Acute gastroenteritis was the second most common; the median number of patients was 23.7 per week per 1000 evacuees (IQR, 5.1-24.3). No other infectious diseases were observed. The median cumulative incidence of ARI per 1000 evacuees in each shelter was 13.1 person-days (IQR, 8.5-18.8). The median cumulative incidence of gastroenteritis was 1.6 person-days (IQR, 0.3-3.4). CONCLUSION: After the Great Eastern Japan Earthquake and tsunami, outbreaks of ARI and acute gastroenteritis occurred in evacuation shelters.