Abstract:

The malaria endemic characteristics in Nanyang, Henan, during 2010-2017 was analyzed in order to formulate some strategies for consolidating malaria elimination in the region. Through the disease surveillance information reporting system of the Chinese Center for Disease Control and Prevention, the epidemiological data of malaria cases in Nanyang, Henan, during 2010-2017 were collected and analyzed for the characteristics of epidemic situation, regional distribution, gender, age and occupational distribution, source of infection, time to get diagnosed and treated and where the case reported from using Excel 2003. The epidemiological results showed that total 375 malaria cases were reported in Nanyang, Henan, from 2010 to 2017, of which 181 cases were clinically diagnosed (48.3%) and 194 cases diagnosed in the laboratory (51.7%). 306 cases were caused by the infection of Plasmodium vivax (81.6%), 61 cases by P. falciparum infection (16.3%), 7 cases by P. Ovale (1.9%), 1 case by P. malariae (0.2%). There were 299 local infections (79.7%) and 76 imported cases (20.3%). P. vivax was the dominant species that caused malaria in Nanyang area during 2010-2011, with local infection and clinically diagnosed cases only. During 2012-2017, there was no local infection anymore and all cases were imported from abroad or other endemic areas and diagnosed in laboratories only. Malaria cases were identified in 13 counties or cities in Nanyang area, with the largest number of cases identified in Tanghe County (61 cases) and the lowest number of cases in Xixia County (5 cases). In the infected patients, males accounted for 69.1% (259/375) and females 30.9% (116/375). The infected cases were identified in people with age from 1 to 86 years old. The number of infected cases in the 40-49 and 50-59 age groups was 24.3% (91/375) and 18.9% (71/375), respectively. The number of infected cases in the 0-9 group was the lowest, accounting for 2.1% (8/375). Malaria cases were mainly seen in local farmers during 2010-2011, then shifted to migrant workers during 2012-2017. In the seasonal distribution, the peak number of local malaria cases in Nanyang during 2010-2011 was observed during May-October, accounting for 80.3% (240/299). However, there was no significant seasonal distribution of 76 imported malaria cases during 2010-2017. Sources of imported malaria cases include Africa (90.7%), Southeast Asia (4.0%), South Asia (4.0%), and Yunnan-Myanmar border (1.3%). The top five countries from which the most imported malaria cases came were Nigeria (21 cases), Angola (11 cases), Cameroon (9 cases), Equatorial Guinea (5 cases) and Uganda (5 cases), accounting for 67.1% of total imported cases (51/76). Since the launch of the Malaria Elimination Action in September 2010, the average time from the onset of malaria to diagnosis has been shortened to 4 days, and the time from diagnosis to the case reporting has been shortened to 1 day. During 2010-2011, most of the malaria cases were diagnosed and reported by Township Clinic (68.4%, 216/316). From 2012 to 2017, the malaria cases were mainly diagnosed and reported by the medical institutions at and above the municipal level (86.4%, 51/59).

Key words: Malaria, Endemic situation analysis, Nanyang