Imported Malaria in a Malaria-Free Region: A Retrospective Analysis of Epidemiological, Clinical, and Therapeutic Patterns in Tizi-Ouzou, Algeria (2018–2024)

Background & objectives: Algeria has been certified as malaria-free since 2019 by WHO and last indigenous case was reported in May 2013; however, imported cases remain a concern for possible for reintroduction. This study aimed to describes the epidemiological, clinical, and therapeutic characteristics of imported malaria cases in the Tizi-Ouzou between 2018 and 2024. Methods: A retrospective descriptive study was conducted in the Department of Infectious Diseases at the University Hospital of Tizi-Ouzou. Data were collected from hospital registers and archived medical records. Only laboratory-confirmed cases, diagnosed by microscopic examination of Giemsa-stained blood smears, were included. Variables included demographics, travel history, Plasmodium species, incubation period, clinical presentation, disease severity, laboratory findings, treatment, preventive measures, and outcomes. Results: Among 106 individuals screened, 16 were confirmed as imported malaria (positivity rate 15.1%). Annual cases fluctuated, with a notable increase from 2022 to 2024, reaching 40% positivity in 2024. Most patients were men (87.5%) and adults aged 20–50 yrs (87.5%), mainly Algerian nationals returning from West Africa. Plasmodium falciparum accounted for 87.5% of cases, often with low parasitemia (< 4 % in 68.8%). No patient had used chemoprophylaxis. Fever with chills and sweats was the most common symptom (92.9%). Uncomplicated malaria representes 78.6% of cases, while 21.4% were severe. The main biological abnormalities were anemia (92.8%), thrombocytopenia (42.8%), and hepatic cytolysis (43%). Mefloquine was the most prescribed treatment (71.4%). Interpretation & conclusion: Imported malaria in Tizi-Ouzou is characterized by P. falciparum predominance, absence of chemoprophylaxis, short post-travel incubation, and travel-linked seasonality. Strengthening pre-travel counseling, improving prophylaxis, uptake, and enhancing clinician awareness are crucial to prevent severe disease and reduce the risk of malaria reintroduction in Algeria.