Abstract:

To analyze the epidemiological characteristics of malaria in Kunming before (2006—2010) and after the malaria elimination plan (2011—2021), which had started in 2010 to provide scientific strategies for the prevention of malaria re-transmission. Data of malaria cases in Kunming from 2006 to 2021 were collected from the Infectious Disease Network Direct Reporting System of the Chinese Center for Disease Control and Prevention. The data were grouped as pre- or post-eradication campaign, which were introduced in 2011. IBM SPSS statistics v26 statistical software was used for descriptive statistical analysis for the three spatial distributions of the cases, the place of infection, the awareness of the patients and the diagnostic capacity. The results showed that a total of 551 malaria cases were reported in Kunming from 2006 to 2021, 274 and 277 cases were reported in 2006—2010 and 2011—2021 respectively, including 5 indigenous cases (2 cases in 2006 and 2008 and 1 case in 2010) and 546 imported cases. The number of reported cases decreased over the year. The distribution of cases was concentrated, and indigenous cases were sporadically distributed in the rural regions from 2006 to 2010. The imported cases were mainly distributed in Guandu District before and after the elimination plan started, accounting for 55.8% (153/274) and 82.7% (229/277), respectively. Malaria cases were distributed in all months from 2006 to 2021, and more cases reported in July (41 cases) and June (48 cases) before and after the plan of action. In 2006—2010 and 2011—2021, the age distribution was mainly young adults aged 20-49 years (83.5%, 460/551), accounting for 82.1% (225/274) and 84.8% (235/277) respectively. The occupational distribution was mainly farmers and workers (57.4%, 316/551), accounting for 56.6% (155/274) and 58.1% (161/277) respectively. From 2006 to 2010, the cases were mainly imported from Southeast Asia (73.0%, 200/274). Of all cases, Plasmodium vivax infection accounted for 39.1% (107/274), P. falciparum infection accounted for 19.0% (52/274) and unclassified accounted for 42.0% (115/274). From 2011 to 2021, most of cases were imported from Africa (57.4%). Of all cases, P. vivax infection accounted for 41.2% (114/277), P. falciparum infection accounted for 52.4% (145/277), mixed infection accounted for 0.2% (5/277), unclassified accounted for 4.0% (11/277). Only one case of P. malariae and one case of P. ovale was reported. Before and after the initiation of the action plan, the time interval between onset of symptoms and visiting a doctor was 2 days, and the difference was not statistically significant (H = 0.568, P > 0.05). The interval between attending a health facility and diagnosis was 4 days and 3 days respectively, and the difference was statistically significant (H = 6.423, P < 0.05). The analysis showed that no indigenous cases were reported in Kunming after the action plan, and the goal of eliminating malaria has achieved as scheduled.

Key words: Malaria, Epidemiological analysis, Kunming, Malaria elimination