Analysis of the spatial-temporal characteristics of measles in two different populations in Minghang District, Shanghai.

[Objective] To analyze the spatial-temporal characteristics of measles in two different populations in Minhang District of Shanghai and clarify the significance of local field strain.[Methods] Measles infection data and relevant demographic data from the years 1993 to 2007 were collected,the incidences were calculated and relative risks(RR) of two different populations in partitioned years were compared.[Results] Seasonal variation was obvious in measles incidence as 55.25% cases were seen from March to May.The incidence showed increasing with time,as the period of 1993-2000,2001-2004 and 2005-2007 in turn,the average incidences(1/10-5)in local population were 0.18,1.89,and 14.84 respectively,whereas in move-in population were 13.33,17.34 and 20.66 respectively.Case distribution in the district was uneven.For local population,the largest patient proportion was aged more than 20,counted for 69.16%.For move-in population groups,most patients lies on 8 month to 4 years old(counted for 29.49%),and on 20-29 age group(counted for 29.38%).[Conclusion] Measles incidence in Minhang District differed in spatial-temporal and population distribution,but the difference between two populations has been diminished since the year of 2005.Local field strains do exist environmentally and the variation in genes and antigenicity should be monitored.