[Malaria situation in the Peoples Republic of China in 2011].
Totally 4 479 malaria cases were reported through the annual reporting system from 782 counties of 27 Provinces/ Municipalities/Autonomous Regions (P/M/A) in 2011, this created a new-low number representing 43.0% reduction compared with 7 855 cases in 2010, and accordingly the annual incidence was reduced to 0.033 4/10 000. However, the number of malaria deaths increased to 33 from 19 in 2010. Among the 782 counties with reported cases, 2 counties of Motuo (16.466 0/10 000) in Tibet and Ruili (12.235 2/ 10000) in Yunnan had an incidence of more than 10/10 000, 10 counties in Yunnan and 1 county in Guizhou had an incidence between 1/10 000 and 10/10 000, and that of the others was below 1/10 000. The malaria areas and transmission got further confined than in 2010. Out of the 4 479 malaria cases, a proportion of 29.3% was reported as the indigenous cases who mainly distributed in the provinces of Anhui (40.0%), Yunnan (25.8%), Henan (12.6%), Guizhou (10.4%) and Hubei (6.1%), a proportion of 66.4% was reported as the abroad-imported cases who mainly distributed in Yunnan (36.5%), Jiangsu (12.0%), Henan (6.2%), Sichuan (5.8%) and Hunan (4.8%), and the remaining 4.3% were domestically-mobile cases. Meanwhile, the confirmed cases took 81.7% while the other 18.3% were clinically diagnosed cases. Among the confirmed cases, 56.7% were Plasmodium vivax cases reported from 25 provinces, 40.2% were P. falciparum cases reported from 22 provinces, 1.1% were mixed infections of P. vivas and P. falciparum reported from 10 provinces, and the remaining 1.9% were P. malariae or P. ovale cases reported from 14 provinces. The 32 indigenous falciparum malaria cases were found only in Yunnan Province. Yunnan was still the major malaria province which ranked No.1 in the country in terms of the case number, 1 522 cases representing 42.4% decrease of the last year with an incidence of 0.331 4/10 000. Among the cases, 301 were falciparum malaria accounting for 20.3% of the national falciparum malaria figure. As previous key malaria province however, Hainan reported only 9 malaria cases indicating 88.5% decrease of the last year with an incidence of 0.010 4/ 10 000, and ranked down to No. 25. In central China, another major malaria region, the case number decreased considerably. However, Anhui still reported 644 malaria cases though with a decrease of 65.5% in comparison to that of 2010, ranked No. 2, accounting for 14.4% of the countrys malaria cases with an incidence of 0.100 0/10 000. In Jiangsu, 374 cases were reported and decreased by 3.1% with an incidence of 0.050 8/10 000. In Henan, the number of reported cases was 358 and decreased by 59.9% with an incidence of 0.038 7/10 000. In Hubei, 167 malaria cases were reported and decreased by 61.1% with an incidence of 0.027 7/10 000. Cases reported from other provinces occupied 31.4% of the total. Respectively from Guizhou, Sichuan, Guangxi, Guangdong, Zhejiang, Hunan and Shandong provinces, 100-200 malaria cases were reported; and the number of cases was less than 100 in the provinces of Fujian, Chongqing, Shanghai, Hebei, Beijing, Tianjin, Xinjiang, Ningxia, Jiangxi, Liaoning, Shaanxi, Shanxi, Gansu and Tibet. Although a delightful progress was made with a substantial reduction of malaria transmission, China had to face the following challenges relating to malaria endemic situation: 1) Malaria cases appeared in almost one thousand counties in most provinces and nearly 200 counties reported indigenous cases. In some counties the transmission is still high, and it is still critical for the provinces of Anhui, Yunnan, Henan, Guizhou, Hubei and Tibet to interrupt the local malaria transmission. 2) Imported malaria cases were dominant and widely distributed in the country including the 4 plasmodium species, this could bring about high risks of re-introduction of malaria transmission in areas where malaria was effectively under control, particularly could cause more malaria deaths in the circumstances of increased imported falciparum malaria cases, therefore provinces with more mobile population and imported cases need to pay higher attention. 3) A number of clinically diagnosed but unconfirmed cases still exist in malaria elimination stage which need to be addressed through strengthening local laboratory diagnosis capabilities.