Abstract
Introduction
Human mobility across the Brazilian Amazon—shaped by frontier development, land-use change, mining activity, and climatic shocks—remains a major barrier to malaria elimination. Brazil aims to eliminate
Plasmodium falciparum (Pf)
by 2030 and
Plasmodium vivax (Pv)
by 2035, yet malaria incidence has plateaued since 2020. We quantify parasite-specific mobility and assess how importations drive malaria reintroduction and reestablishment in areas approaching elimination.
Methods
We analyzed 5,521,411 de-identified malaria cases from Sivep-Malaria (2003–2023) across 808 municipalities in the nine-state Brazilian Amazon. We (i) used multivariable monthly sequence analysis to classify “Municipal Malaria Importation Trajectories” (MMITs) using local/imported composition, incidence per 1,000, and source/sink network typologies; (ii) characterized mobility networks by parasite species and locality type (rural, urban, settlement, indigenous, mining); and (iii) developed a parasite-specific rule-based classification procedure to identify reintroduction, and defined reestablishment as sustained local transmission.
Results
Sequence analysis produced five MMIT clusters, spanning municipalities nearing elimination to areas with sustained high local transmission and distinct profiles of declining transmission with intense vs. moderate importation. Overall, 959,281 cases (17.38%) were imported. Cases were predominantly
Pv
(81.68%), with
Pf
comprising 17.15%;
Pf
was more common among imported than locally acquired infections. Mobility patterns shifted after mid-2020: by 2023, > 50% of exported cases originated in mining localities despite ~0.2% land coverage, with
Pf
importation increasingly concentrated in municipalities overlapping the Yanomami Indigenous Land. From 2006–2023, we identified 63
Pf
and 221
Pv
reintroduced locally acquired cases following ≥3 years of zero local transmission, leading to reestablishment in 6 and 23 municipalities, respectively, and generating 864 subsequent
Pf
and 6,524 subsequent
Pv
cases. Post-reintroduction transmission persisted for long periods (mean 762 days for
Pf
; 815 days for
Pv
).
Conclusion
Malaria elimination in Brazil is increasingly hindered by parasite-specific mobility, especially linked to mining–indigenous confluences, and by repeated reintroduction in receptive municipalities nearing elimination (notably along the arc of deforestation). Mobility-informed surveillance and targeted reactive strategies are essential to achieve and sustain Brazil’s malaria elimination goals.