Trends of imported malaria in China 2010-2014: analysis of surveillance data.

BACKGROUND: To describe the epidemiologic profile and trends of imported malaria, and to identify the populations at risk of malaria in China during 2010-2014.

METHODS: This is a descriptive analysis of laboratory confirmed malaria cases during 2010-2014. Data were obtained from surveillance reports in the China Information System for Disease Control and Prevention (CISDCP). The distribution of imported malaria cases over the years was analysed with X(2) for trend analysis test. All important demographic and epidemiologic variables of imported malaria cases were analysed.

RESULTS: Malaria incidence in general reduced greatly in China, while the proportion of Plasmodium falciparum increased threefold from 0.08 to 0.21 per 100,000 population during the period 2010-2014. Of a total 17,725 malaria cases reported during the study period, 11,331 (64%) were imported malaria and included an increasing trend: 292 (6%), 2103 (63%), 2151 (84%), 3881 (96%), 2904 (97%), respectively, (X(2) = 2110.70, p < 0.01). The majority of malaria cases (imported and autochthonous) were adult (16,540, 93%), male (15,643, 88%), and farming as an occupation (11,808, 66%). Some 3027 (94%) of imported malaria cases had labour-related travel history during the study period; 90% (6340/7034) of P. falciparum infections were imported into China from Africa, while 77% of Plasmodium vivax infections (2440/3183) originated from Asia.

CONCLUSIONS: Malaria elimination in China faces the challenge of imported malaria, especially imported P. falciparum. Malaria prevention activities should target exported labour groups given the increasing number of workers returning from overseas.