[Diagnosis of imported malaria cases in Henan Province from 2015 to 2019]

Objective: To analyze the diagnosis of imported malaria cases in Henan Province from 2015 to 2019, so as to provide the evidence for malaria surveillance during the post-elimination stage.

Methods: The data pertaining to malaria cases in Henan Province from 2015 to 2019 were extracted via the web-based Chinese Information System for Infectious Diseases Control and Prevention and the Parasitic Diseases Information Reporting Management System (PDIRMS) of Chinese Center for Disease Control and Prevention, and the diagnostic methods, diagnostic institutions and diagnostic time of imported malaria cases were analyzed.

Results: A total of 952 imported malaria cases were reported in Henan Province during the period from 2015 through 2019, and all cases were laboratory-confirmed. The positive rate of malaria rapid diagnostic tests (RDTs) was 98.61% (779/790), which was significantly greater than that (94.22%, 897/952) of microscopic examinations (χ² = 22.773, P < 0.05). The proportion of imported malaria cases diagnosed in medical institutions increased from 65.22% (120/184) in 2015 to 81.50% (185/227) in 2019. Among the 238 imported malaria cases diagnosed in centers for disease control and prevention (CDC), 71.01% (169/238) were diagnosed in county-level CDC, and among the 704 cases diagnosed in medical institutions, only 8.38% (59/704) were diagnosed at county-level medical institutions. The median time from onset to definitive diagnosis of malaria was 3 days, and the median duration between onset and initial diagnosis of malaria was 1 day. The duration between initial diagnosis and definitive diagnosis of malaria varied significantly among years (χ² = 24.956, P < 0.05), and the interquartile range from initial diagnosis to definitive diagnosis reduced from 4 days in 2016 to 2 days in 2019. In addition, the median time from initial diagnosis to definitive diagnosis was significantly longer in severe falciparum malaria cases than in non-severe falciparum malaria cases (2 days vs. 1 day; Z = 7.557, P < 0.05).

Conclusions: Medical institutions play a more and more important role in the identification and surveillance of malaria cases; however, the diagnostic capability of malaria remains low in county-level medical institutions. The diagnostic awareness and capability of county-level medical institutions requires to be improved, in order to play their roles as sentinel hospitals in the malaria surveillance during the post-elimination stage.