| BackgroundSince the 1990 s, with the changing of the epidemiological characteristics, the phenomenon "pertussis reappearance" appeared on a global scale. There are such causes of pertussis reappearance as pertussis disease characteristics, attenuation of antibody vaccine, medical staff's attitude and the application of laboratory diagnosis technology, whooping cough outbreaks from 2014 through 2015 in Jinan was popular, but whether it was "pertussis reappearance" and inspectors reasons are still unknown.ObjectiveTo analyze the epidemiological characteristics of pertussis in Jinan during 2005-2015, and provide scientific evidences for the prevention and control of pertussis. To investigate the implementation of pertussis diagnostic standards and the application of laboratory methods in Jinan.MethodExce12007, SPSS20.0 and Arcgisl0.2 were used to analysis epidemiological characteristics of pertussis cases in Jinan during 2005-2015. Relevant data were collected from medical staff in 49 secondary or tertiary hospitals were investigate by interviews and questionnaires, and were analyzed in combination with reported pertussis incidences. Chi square test, Kruskal-Wallis test (K-W test) were used to analysis the distribution of cases.Results1.The average incidence rate of pertussis in 2005-2015 was 0.96 per 100000.The incidence peaks happened in 2014-2015 with incidence of 2.98 and 4.70 per 100000,respectively. Epidemic season is summer and autumn.2. Regionally, incidence rates of urban area were less than the suburbs in 2005-2011 and there were no statistically significant differences. Incidence rates of urban area were higher than the suburbs in 2005-2011 and the difference was statistically significant only in 2014 (P=0.02<0.05).Incidence rates of urban and suburb in 2014were 3.57 and 2.28 per 100000, respectively and in 2015 were 4.88 and 4.47 per 100000, respectively. Rise range of suburb cases were far more than urbans during 2014-2015.3.On the distribution of occupation in 2005-2015, the proportion of scattered children decreased from 100% to 71.30%, the proportion of preschools children increased from 0% to 14.80% and students rose from 0% to 9.37%. The difference was statistically significant (P=0.00<0.05).4.The proportion of cases younger than 6 years old dropped from 100% in 2007-2010 to 88.52% in 2015 and cases younger than 1 year fallen from 86.21% in 2010 to 41.09%.the proportion of teenagers (aged 7-25) cases rose from 0% in 2010 to 7.25% in 2015. Adult patients (over 26 years) appeared in2014-2015. There was significant difference in the age distribution of the cases (P=0.01<0.05). Incidence increased year by year. The highest incidences among all the age groups were cases younger than 1 years and 1 years old. Of which the highest were in 2015 (199.8 per 100000,85.8 per 100000), the lowest were the average of 2005-2009 (3.1 per 100000,0.3 per 100000).The proportion of laboratory confirmed cases rose from 3.45% in 2010 to 79.46% in 2015.5.39 (79.59%) of 49 hospitals performed the clinical diagnosis of pertussis, in which the secondary and tertiary hospitals accounted for 61.54%and 38.46%, respectively. In 39 medical staff from hospitals performing pertussis diagnosis, the correct selection rates of typical pertussis symptoms were 100% for paroxysmal and spasmodic cough,94.87% for 2-weekcontinuouscough, and 87.18%for crowing voice; the correct selection rates of atypical symptoms were 30.77% for cyanosis,20.51% for bradycardia,20.51% for asphyxia, and 15.38% for recurrent apnea. The accuracy of performing diagnostic standards for clinical and confirmed cases was 35.90%. The proportion of laboratory confirmed pertussis cases in Jinan increased from 18.75% in 2012 to 56.88% in 2014 and 79.4% in 2015; the incidences in 2014-2015 were higher than before, even if excluding laboratory confirmed cases.ConclusionWith the shift of cases from children to adolescents and adults, the outbreak of pertussis In Jinan City in 2014-2015 is similar to the phenomenon of "Reemergence of Pertussis" in Europe and America. The improvement of diagnostic level and monitoring level of Jinan City, the immune persistence of pertussis vaccine, the epidemiological characteristics of pertussis population and the increase of floating population are likely to be the reasons for the increase of incidence rate in Jinan city in recent years. Close attention should be paid to the trend of pertussis disease, and take targeted measures to prevent and control it. |
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