Epidemiological study on outbreak of respiratory infection due to Adenovirus

  Objective   To explore the epidemiological and pathogenic cause of slight acute respiratory tractinfection syndrome which broke out in Dongtai areas, Jiangsu Province in 2004.

  Methods   Tolay down the clinical standard for the diag nosis cases; to take investigation to every case by using the same epidemiological questionnaire, and to describe the epidemiological characteristics.To analyze the epidemic factors by the method of case control; to cellect the specimen of pharyngeal swab for the sufferer in epidemic areas to separ ate and culture etiology agent; to test the positive specimens by suing immunofluor escence, PCR, electron microscope technology and neutralize test to the cowple serum of the cases.

  Results   There were 871 cases of acute respiratory tract infection syndrome, covering ten townships.Two incidence peaks occurred in the last ten days of May and in the middle ten days of June.Most cases(94.37%)were pupils in the primary and high school or the children in the kindergartens, and some of the cases(5.63%)were non students.The adults were hardly infected.The age scope of the cases ranged from 7 months to 18 years old.The clinical characteristics were fever accompanied by angina and tonsillitis.The course of diseases was about 5 days, and prog nosis was all right and no death cases.The study of case control showed that the risk factors were to contact with fever cases, to couse towel within family and to nearly contact with chooks.The specimens were separated and cultured throughouthep-2 cells in two different laboratory, and obvious cellular pathological changes, where the cells presented the form of grapes cluster and the refraction ability of cells had been enhanced, appeared in the 51~65 percent of the speciments.The large amount typical granule of adenov irus, where array of cells presents crystal lattice, could be observed in the nucleouls under electron microscope.Infection by adenov irus could be proved by direct immunofluorescence test, RT-PCR, and neutralize test to the couple of serum.The virus was confirmed as adenovirus type by the method of checking and measuring the virus whole geens sequence.

  Conclusion   The agent of acute respiratory tractinfection syndrome br eaking out in Dongtai areas was confirmed as adenovirus, and the transmission route mainly were to contact with the aerosol in the air and cases.