Epidemiological survey of an infectious erythema outbreak in a school

ObjectiveTo investigate the scale and pathogen of an unexplained rash outbreak in a school in Baoan district of Shenzhen, identify the risk factors and propose targeted prevention and control measures.

MethodsOn April 4, 2018, the investigation and epidemic response was carried out in the school. The case definition was developed for case finding, standard epidemiological questionnaire was used for field survey, and the distribution characteristics of the cases were described. A retrospective cohort study was conducted to identify the risk factors, and blood samples were collected from the cases for pathogen antibody detection.

ResultsA total of 12 cases were found, the attack rate was 11.9% (12/101). Four blood samples were collected, all were positive for human parvovirus B19 IgM and IgG antibody. According to the result of the retrospective cohort study, sitting next to the cases in class ［RR＝4.3 (1.2–14.9)］ or playing chess with the cases ［RR＝5.7(1.3–24.7)］ were the risk factors for the infection.

ConclusionThis epidemic was an infectious erythema outbreak caused by human parvovirus B19. Close contact, such as sitting next to the case in class or playing chess with the case, was the risk factor for the infection.