Abstract:

Objective To analyze the malaria monitoring data in Guizhou Province from 2005 to 2016 and understand epidemiological characteristics, in order to provide reference for formulating and adjusting strategies and measures for malaria prevention. Methods Data on malaria cases and epidemiological investigations in Guizhou Province from 2005 to 2016 were collected and analyzed with regard to the incidence and distribution of malaria, diagnosis of cases, Plasmodium species constitution, and sources of infection for imported cases. Results During 2005-2016, a total of 4 578 malaria cases were reported in the Province, of whom 4 429 (96.7%) were indigenous cases, 16 (0.3%) were imported from other places in China, and 133 (2.9%) from other countries. These cases consisted of 2 965 (64.8%) vivax malaria, 89 (1.9%) falciparum malaria, 9 (0.2%) ovale malaria, 2 (0.1%) quartan malaria, 2 (0.1%) mixed infections, and 1 511 (33%) unclassified cases. Among all the cases, 3 217 (73%) were clinically diagnosed, all reported during 2005-2011; and 1 361 cases (29.7%) were diagnosed with laboratory tests. The laboratory diagnosis rate has been reaching 100% since 2012. Specifically, the cases reported during 2005-2011 were mainly indigenous cases, distributed mostly in South Qian Autonomous Prefecture, Southeast Qian Autonomous Prefecture, and Southwest Qian Autonomous Prefecture (92.2%, 4 085/4 429). From 2012 on, no indigenous cases were reported, the 106 cases reported were all imported from other countries, and mainly distributed in Guiyang and Zunyi cities (60.2%, 80/133). They were mainly from African countries (86, 64.7%), followed by Southeast Asia (40, 30.1%). Most of the cases were males (3 101, 67.7%). For the occupation distribution, the indigenous cases were predominated by farmers (3 357, 75.8%), followed by students (478, 10.8%); while the imported cases from other countries were mainly farmers (35, 26.3%) and workers (34, 25.6%). The malaria incidence among indigenous cases peaked from July to September, a time coinciding with the endemic season of malaria, and the cases imported from other countries occurred throughout the year, with no significant seasonal variation. Conclusion The endemic situation of indigenous malaria cases has been effectively controlled in Guizhou Province, achieving the goal of malaria elimination. Control of malaria imported from other countries will be the focus of the project in the future.

Key words: Malaria, Epidemiological characteristics, Guizhou Province