Risk Factors for Imported Severe Malaria Cases - China, 2019-2023.

Abstract

Objective: To analyze the epidemiological characteristics of imported malaria in China from 2019 to 2023 and to explore risk factors for severe malaria cases, thereby providing a theoretical basis for early clinical identification and intervention of severe malaria.

Methods: National malaria case data were retrospectively collected from 2019 to 2023 through the Chinese Center for Disease Control and Prevention Parasitic Disease Prevention and Control Information System. Study subjects were divided into severe and non-severe malaria cases, and the characteristics of both groups were analyzed. Multivariate logistic regression analysis was used to explore risk factors for developing severe malaria.

Results: From 2019 to 2023, a total of 7,892 imported malaria cases were reported nationwide, including 673 severe cases and 7,219 non-severe cases. There were 7,353 (93.2%) male and 539 (6.8%) female patients. Compared to non-severe malaria patients, severe malaria patients were older (43.9±10.4 years), predominantly originated from Africa (643,95.5%), had a higher frequency of recent overseas residence within the past month (609,90.5%), were typically infected with P. falciparum (527,78.3%), and had a higher mortality rate (47,7.0%). Severe cases had longer median time intervals from symptom onset to medical visit (4 days), from visit to diagnosis (2 days), and from diagnosis to treatment (2 days), and a longer median medication time (7 days), all P<0.05.

Conclusions: This study identified risk factors for severe malaria and recommends focusing on monitoring patients' age, infection source, Plasmodium species, time from onset to hospital visit, and recent history of foreign residence. These findings provide a valuable reference for effectively managing malaria cases and reducing the incidence of severe malaria in the future.