Malaria in Zhejiang Province, China, from 2005 to 2014

To summarize the changing epidemiological characteristics of malaria in Zhejiang Province, China, we collected data on malaria from the Chinese Notifiable Disease Reporting System (NDRS) and analyzed them. A total of 2,738 malaria cases were identified in Zhejiang Province from 2005 to 2014, of which 2,018 were male and 720 were female. Notably, only 7% of malaria cases were indigenous and the other cases were all imported. The number of malaria cases increased from 2005 to 2007, peaked in 2007, and then decreased from 2007 to 2011. There were no indigenous cases from 2012 to 2014. Of all cases, 68% of cases contracted Plasmodium vivax, 27% of cases contracted P. falciparum, and two cases contracted P. malariae. About 88% of malaria cases during 2005-2011 occurred yearly between May and October, but the number of malaria cases in different months during 2012-2014 was similar. The median age was 33 years, and 1,892 cases occurred in persons aged 20-50 years. The proportion of businessmen increased and the proportion of migrant laborers decreased in recent years. The median time from illness onset to confirmation of malaria cases was 5 days and it decreased from 2005 to 2014. Some epidemiological characteristics of malaria have changed, and businessmen are the emphases to surveillance in every month.