Malaria in Southeastern China from 2012 to 2016: Analysis of Imported Cases

To study the epidemiological distribution and the incident trends of imported malaria from 2012 to 2016 in Zhejiang Province, southeastern China, we collected data on malaria from the Information System for Parasitic Disease Control and Prevention. A total of 1,003 malaria cases were reported during 2012-2016, and all of these cases were imported. Plasmodium falciparum was the predominant species (76.3%) in Zhejiang Province. The percentage of Plasmodium vivax decreased from 33.6% to 8.1%, whereas the percentage of Plasmodium ovale and Plasmodium malariae increased. Most cases were male (89.8%), mostly in the age group of 21-50 years (82.6%). Businessmen (33.0%), workers (21.0%), farmers (18.8%), and overseas laborers (11.7%) were at high risk. The origin of the largest number of imported cases was Africa (89.5%), followed by Asia (10.0%) and Oceania (0.5%). The time interval from illness onset to confirmation was found to be significantly associated with the complications of patients. Out of 3,461 febrile individuals tested during reactive case detection, 10 malaria-positive individuals were identified. Effective surveillance and response system should be strengthened to prevent the reintroduction of malaria.