Burden of asymptomatic malaria in Sub-Saharan migrants attending an outpatient clinic in Rome from February 2024 to January 2025.

Abstract BackgroundSub-Saharan African (SSA) migrants may harbor asymptomatic Plasmodium infections long after leaving endemic regions, representing a potential public health concern in host countries. However, data on the prevalence and persistence of such infections post-migration are limited.MethodsBetween February 2024 and January 2025, SSA migrants attending the Lazzaro Spallanzani Institute’s mobile population clinic were screened for malaria using rapid diagnostic tests (RDTs), thick blood smears, and PCR. Eligibility criteria included age ≥ 16, absence of fever, and origin or transit through malaria-endemic regions. Additional screenings for tuberculosis, schistosomiasis, and viral hepatitis were also conducted.ResultsAmong 87 asymptomatic migrants tested, PCR detected Plasmodium spp. in 5 cases (6.02%), while RDT identified 2 (2.29%). Identified species included P. falciparum, P. malariae, P. ovale, and one mixed infection. The longest time since arrival among positive cases was 181 days; including detention in Libya, the median duration since departure from endemic areas was over 600 days.ConclusionsAsymptomatic malaria persists months after arrival and is underdetected by RDTs. PCR enhances diagnostic sensitivity, supporting its use in screening migrants from endemic areas. These findings highlight the need for inclusive, long-term infectious disease screening policies tailored to mobile populations.