[Epidemiological characteristics and diagnosis of imported malaria cases in Zhejiang Province from 2017 to 2020]

To analyze the epidemiological features and diagnosis of imported malaria cases in Zhejiang Province from 2017 to 2020, so as to provide the scientific evidence for the management of imported malaria in the province.

The data of malaria cases reported in Zhejiang Province were captured from the Information Management System for Parasitic Disease Control of China Information System for Disease Control and Prevention from 2017 to 2020, and the temporal, spatial and human distribution, and initial and definitive diagnosis of imported malaria cases were descriptively analyzed.

A total of 593 malaria cases were reported in Zhejiang Province from 2017 to 2020, and all were overseas imported cases, including 532 men and 61 women, with a mean age of 41 years. There were 93.93% of the malaria cases from African countries, and the malaria parasites infecting these cases included Plasmodium falciparum, P. vivax, P. ovale, P. malariae and mixed infections, with P. falciparum as the predominant species (76.73%, 455/593). All malaria cases received totally correct initial diagnoses in county- and city-level centers for disease control and prevention (CDC) and entry-exit inspection and quarantine sectors, and the proportion of malaria cases with confirmation at the day of initial diagnosis was 41.48% (207/499) in medical institutions and 66.18% (45/68) in CDC (χ² = 14.779, P < 0.001). In addition, the median interval [M (Q)] of malaria cases was 1 (2) d from onset to initial diagnosis and 1 (2) d from initial diagnosis to confirmation in Zhejiang Province from 2017 to 2020, and the median interval [M (Q)] of severe malaria cases was significantly longer than that of non-severe cases [2 (3) d vs. 1 (2) d; Z = -3.002, P < 0.05].

Zhejiang Province faces great challenges of malaria control, and post-elimination surveillance of malaria still requires to be reinforced. Meanwhile, the awareness of seeking medical services requires to be improved among returners from malaria-endemic regions and the diagnostic capability of malaria requires to be improved among medical professionals.