Abstract:
Objective To investigate the pathogenic and epidemiologic factors of an outbreak of pharyngoconjunctival fever occurred in adolescents in Conghua, Guangdong province, in August 2013.
Methods The established standardized case definition and unified epidemiologic questionnaires were used to investigate the cases and describe the epidemiologic characteristics. A case control study was conducted, PCR was performed to detect the pharyngeal and eye swabs collected from the cases.
Results A total of 89 cases of pharyngoconjunctival fever were reported in Conghua, and 58 cases (65.17%)occurred in Jiekou town. The attack rate was 5.82‰. Up to 66.29% of the cases (59/89) were aged 6–10 years . Most cases (94.38%, 84/89) occurred from 10 August to 17 August. The clinical characteristics were fever accompanied by pharyngalgia, tonsillitis or conjunctivitis. The prognosis was good and no death was reported. Up to 86.52% (77/89) of the patients had the history of swimming. The case control study showed that the risk factors included choking water in swimming pool (OR=3.49, 95% CI: 2.07–11.49).Among 41 clinical samples, 17 were positive for adenovirus nucleic acid, the positive rate was 41.46%. The sequencing results of PCR products indicated that the pathogen was adenovirus type 4.
Conclusion It was confirmed that the pathogen causing the pharyngoconjunctival fever outbreak in Conghua was adenovirus, and swimming in unqualified natatorium was the main route of transmission.