Objective To further identify the high-risk population at malaria elimination phase, and to provide the scientific evident for targeted prevention and control measures, we compared the demographical feature and its change trend for malaria cases between malaria control stage and elimination stage in China. Methods The data of individual case (probable and confirmed) and population during 2007-2014 were collected from China National Notifiable Infectious Disease Reporting Information System, and the data of epidemiological investigation for malaria case (imported and indigenous) during 2011-2014 were collected from China Parasite Disease Prevention and Control Information System. All of the data didn 't include China's Hongkong, Macao, Taiwan and foreign cases. We described the demographic features of malaria cases, e.g. sex, age, occupation and mobility, to compare the differences of cases between malaria control stage (2007-2010) and the elimination phase (2011-2014). Results From 2007 to 2014, a total of 108 076 malaria cases were reported nationwide, which 13 355 cases were reported at the elimination stage. The proportion of male cases considerably increased from 65.1%(6 1625 cases) at the control stage to 91.4%(12 209 cases) at the elimination phase, with the cases aged 15-64 years among male cases dramatically rose from 74.3%(45 793 cases) to 97.2%(11 870 cases). In terms of occupation, the proportion of children and students decreased from 17.8% (16 891 cases) to 2.7% (356 cases), while the percentage of migrant workers, workers and other professional cases increased from 8.5% (8 031 cases), 3.5% (3 319 cases) and 3.6% (3 435 cases) to 13.1% (1 757 cases), 11.5% (1 534 cases) and 11.4% (1 517 cases), respectively. During the elimination stage, P. faliparium cases have higher proportion of male (96.4%, 7 179 cases) and adult aged 15-64 year (99.4%, 7 399 cases) than that of P. vivax cases , 83.9%(4 344 cases) and 90.3%(4 679 cases), respectively. Moreover, the proportion of imported cases rose from 63.6% (2 599 cases) in 2011 to 97.7%(2 854 cases) in 2014, and the proportion of the migrants in indigenous cases also showed an increasing trend from 13.5%(201 cases) in 2011 to 28.4%(19 cases) in 2014. Conclusion Compared with the control stage, great changes of demographical characteristics of malaria cases occurred at the elimination stage. Male adults aged 15-64 year-old, imported cases and domestic migrants were the high-risk population for targeted control and prevention at the malaria elimination stage.

Objective To explore the epidemiological features of deaths of malaria from 2005 to 2014, so as to provide the evidence for subsequently more effective strategic planning of malaria elimination in China. Methods The data of individual malaria cases (including probable and confirmed cases, population data, geographic distribution, diagnosis and reporting information) were obtained from the National Notifiable Infectious Disease Reporting Information System from 2005 to 2014 and the epidemiological investigation information (including the clinical systems and the imported and indigenous cases) was extracted from Parasite Disease Prevention and Control Information System from 2011 to 2014. All of the data didn't include Hongkong, Macao, Taiwan and foreign cases. The population characteristics, clinical systems, geographic distribution, diagnosis and reporting and sources of infections of deaths were analyzed. Results From 2005 to 2014, a total of 228 deaths of malaria were reported, with 203 (89.0%) of P. falciparum malaria, 13 (5.7%) of P. vivax malaria, 1 (0.5%) of P. malariae malaria and 11(4.8%) other cases. The fatality rate of malaria increased since 2010. Among the deaths, 48 (81.4%) had serious complications, which included cerebral lesion, coma, severe renal and hepatic injuries and hemolysis and so on. In 2005-2010, the geographical distribution of malaria deaths was mainly in Yunnan (78 deaths, 56.1%), Sichuan (13 deaths, 9.4%), Henan (7 deaths, 5.0%), Shandong (6 deaths, 4.3%) and Zhejiang (5 deaths, 3.6%) province. However, since the initiation of malaria elimination program in 2010, the areas with malaria deaths have changed, which mainly distributed in Henan (10 deaths, 11.2%), Sichuan (9 deaths, 10.1%), Shandong (8 deaths, 9.0%), Jiangsu (7 deaths, 7.9%) and Hunan province (7 deaths, 7.9%). Besides there were nine deaths (10.0%) reported in non-endemic areas of malaria (Beijing, Inner Mongolia, Jilin, and Ningxia) in 2011-2014. The median time from illness onset to diagnosis for deaths was 5.5 (P25-P75:3.0-8.5) d, which was longer than 3.0 (2.0-6.0)d for survivors. Moreover, for deaths, the median P50 (P25-P75)(6.0, 4.0-9.0 d) from illness onset to diagnosis in 2011-2014 was longer than that in 2005-2010 (5.0, 3.0-9.0 d). Among imported deaths, 77 deaths (90.6%) originated from Africa and 8 deaths (9.4%) from Southeast Asia. Conclusion Although the reported deaths of malaria were stable in 2005-2014, the geographical distribution of malaria deaths changed significantly and the time from illness onset to the diagnosis was longer since 2010. Special attention should be paid to the diagnosis and treatment of imported cases to reduce the fatality at the malaria elimination stage.

Objective To investigate the epidemiological characteristics and impact factors on hospitalization of Plasmodium vivax (P.vivax) since initiation of national malaria elimination program, so as to facilitate the adjustment of technical guideline in response to the epidemic changing of malaria in China. Methods The data of individual P. vivax case (probable and confirmed) and population during 2011-2014 were collated from China National Notifiable Infectious Disease Reporting Information System, and the data of epidemiological investigation for individual P. vivax case (imported and indigenous) during 2011-2014 were collected from China Parasite Disease Prevention and Control Information System. All of the data didn 't include China's Hongkong, Macao, Taiwan and foreign cases. The risk factors on hospitalization were explored by multiple factors variable binary classification unconditioned logistic regression model. Results During study period of four years, a total of 5 656 Plasmodium vivax cases were detected. Among them, 69.9% (3 951 cases) were imported cases and 30.1% (1 705 cases) were autochthonous cases. The male cases accounted for 82.7%of all cases. Among the autochthonous cases, 535 cases (31.4%) occurred in the cross-bordering areas, and 577 cases (33.8%) were reported in the junction of difference provinces. The amount of autochthonous cases decreased from 1 363 cases in 2011 to 53 cases in 2014, and the county affected by autochthonous cases was shrunk from 185 counties to 10 counties. The proportion of autochthonous cases introduced by domestic migrants increased constantly, which reached 41.5%in 2014. The imported cases were detected from 614 counties of 30 provinces, who were originated from 57 overseas countries of 4 continents, with Southeast Asia being the leading origins (2 772 cases, 70.2%). There were 1 494 cases hospitalized for treatment, with the male (OR=1.41, 95%CI: 1.16-1.71), 14 years old and younger (OR=2.26, 95%CI:1.44-3.56), and oversea imported cases (OR=2.73, 95%CI:2.30-3.25) were the high risk group for hospitalization. Conclusion The scale and scope of P. vivax occurrence decreased dramatically since initiation of malaria elimination grogram in 2010. However, the risk of P. vivax introduction by the overseas imported cases and domestic migrants should be highlighted.

Objective To further identify the high-risk population at malaria elimination phase, and to provide the scientific evident for targeted prevention and control measures, we compared the demographical feature and its change trend for malaria cases between malaria control stage and elimination stage in China. Methods The data of individual case (probable and confirmed) and population during 2007-2014 were collected from China National Notifiable Infectious Disease Reporting Information System, and the data of epidemiological investigation for malaria case (imported and indigenous) during 2011-2014 were collected from China Parasite Disease Prevention and Control Information System. All of the data didn 't include China's Hongkong, Macao, Taiwan and foreign cases. We described the demographic features of malaria cases, e.g. sex, age, occupation and mobility, to compare the differences of cases between malaria control stage (2007-2010) and the elimination phase (2011-2014). Results From 2007 to 2014, a total of 108 076 malaria cases were reported nationwide, which 13 355 cases were reported at the elimination stage. The proportion of male cases considerably increased from 65.1%(6 1625 cases) at the control stage to 91.4%(12 209 cases) at the elimination phase, with the cases aged 15-64 years among male cases dramatically rose from 74.3%(45 793 cases) to 97.2%(11 870 cases). In terms of occupation, the proportion of children and students decreased from 17.8% (16 891 cases) to 2.7% (356 cases), while the percentage of migrant workers, workers and other professional cases increased from 8.5% (8 031 cases), 3.5% (3 319 cases) and 3.6% (3 435 cases) to 13.1% (1 757 cases), 11.5% (1 534 cases) and 11.4% (1 517 cases), respectively. During the elimination stage, P. faliparium cases have higher proportion of male (96.4%, 7 179 cases) and adult aged 15-64 year (99.4%, 7 399 cases) than that of P. vivax cases , 83.9%(4 344 cases) and 90.3%(4 679 cases), respectively. Moreover, the proportion of imported cases rose from 63.6% (2 599 cases) in 2011 to 97.7%(2 854 cases) in 2014, and the proportion of the migrants in indigenous cases also showed an increasing trend from 13.5%(201 cases) in 2011 to 28.4%(19 cases) in 2014. Conclusion Compared with the control stage, great changes of demographical characteristics of malaria cases occurred at the elimination stage. Male adults aged 15-64 year-old, imported cases and domestic migrants were the high-risk population for targeted control and prevention at the malaria elimination stage.

Objective To explore the epidemiological features of deaths of malaria from 2005 to 2014, so as to provide the evidence for subsequently more effective strategic planning of malaria elimination in China. Methods The data of individual malaria cases (including probable and confirmed cases, population data, geographic distribution, diagnosis and reporting information) were obtained from the National Notifiable Infectious Disease Reporting Information System from 2005 to 2014 and the epidemiological investigation information (including the clinical systems and the imported and indigenous cases) was extracted from Parasite Disease Prevention and Control Information System from 2011 to 2014. All of the data didn't include Hongkong, Macao, Taiwan and foreign cases. The population characteristics, clinical systems, geographic distribution, diagnosis and reporting and sources of infections of deaths were analyzed. Results From 2005 to 2014, a total of 228 deaths of malaria were reported, with 203 (89.0%) of P. falciparum malaria, 13 (5.7%) of P. vivax malaria, 1 (0.5%) of P. malariae malaria and 11(4.8%) other cases. The fatality rate of malaria increased since 2010. Among the deaths, 48 (81.4%) had serious complications, which included cerebral lesion, coma, severe renal and hepatic injuries and hemolysis and so on. In 2005-2010, the geographical distribution of malaria deaths was mainly in Yunnan (78 deaths, 56.1%), Sichuan (13 deaths, 9.4%), Henan (7 deaths, 5.0%), Shandong (6 deaths, 4.3%) and Zhejiang (5 deaths, 3.6%) province. However, since the initiation of malaria elimination program in 2010, the areas with malaria deaths have changed, which mainly distributed in Henan (10 deaths, 11.2%), Sichuan (9 deaths, 10.1%), Shandong (8 deaths, 9.0%), Jiangsu (7 deaths, 7.9%) and Hunan province (7 deaths, 7.9%). Besides there were nine deaths (10.0%) reported in non-endemic areas of malaria (Beijing, Inner Mongolia, Jilin, and Ningxia) in 2011-2014. The median time from illness onset to diagnosis for deaths was 5.5 (P25-P75:3.0-8.5) d, which was longer than 3.0 (2.0-6.0)d for survivors. Moreover, for deaths, the median P50 (P25-P75)(6.0, 4.0-9.0 d) from illness onset to diagnosis in 2011-2014 was longer than that in 2005-2010 (5.0, 3.0-9.0 d). Among imported deaths, 77 deaths (90.6%) originated from Africa and 8 deaths (9.4%) from Southeast Asia. Conclusion Although the reported deaths of malaria were stable in 2005-2014, the geographical distribution of malaria deaths changed significantly and the time from illness onset to the diagnosis was longer since 2010. Special attention should be paid to the diagnosis and treatment of imported cases to reduce the fatality at the malaria elimination stage.

Objective To investigate the epidemiological characteristics and impact factors on hospitalization of Plasmodium vivax (P.vivax) since initiation of national malaria elimination program, so as to facilitate the adjustment of technical guideline in response to the epidemic changing of malaria in China. Methods The data of individual P. vivax case (probable and confirmed) and population during 2011-2014 were collated from China National Notifiable Infectious Disease Reporting Information System, and the data of epidemiological investigation for individual P. vivax case (imported and indigenous) during 2011-2014 were collected from China Parasite Disease Prevention and Control Information System. All of the data didn 't include China's Hongkong, Macao, Taiwan and foreign cases. The risk factors on hospitalization were explored by multiple factors variable binary classification unconditioned logistic regression model. Results During study period of four years, a total of 5 656 Plasmodium vivax cases were detected. Among them, 69.9% (3 951 cases) were imported cases and 30.1% (1 705 cases) were autochthonous cases. The male cases accounted for 82.7%of all cases. Among the autochthonous cases, 535 cases (31.4%) occurred in the cross-bordering areas, and 577 cases (33.8%) were reported in the junction of difference provinces. The amount of autochthonous cases decreased from 1 363 cases in 2011 to 53 cases in 2014, and the county affected by autochthonous cases was shrunk from 185 counties to 10 counties. The proportion of autochthonous cases introduced by domestic migrants increased constantly, which reached 41.5%in 2014. The imported cases were detected from 614 counties of 30 provinces, who were originated from 57 overseas countries of 4 continents, with Southeast Asia being the leading origins (2 772 cases, 70.2%). There were 1 494 cases hospitalized for treatment, with the male (OR=1.41, 95%CI: 1.16-1.71), 14 years old and younger (OR=2.26, 95%CI:1.44-3.56), and oversea imported cases (OR=2.73, 95%CI:2.30-3.25) were the high risk group for hospitalization. Conclusion The scale and scope of P. vivax occurrence decreased dramatically since initiation of malaria elimination grogram in 2010. However, the risk of P. vivax introduction by the overseas imported cases and domestic migrants should be highlighted.