Spatiotemporal dynamics of malaria and climate influence on its incidence in Condorcanqui Province, 2005-2022.

Abstract

Background: Amazonas is a region in northern Peru with the second-highest incidence of malaria. Approximately 95% of the cases are reported in the Condorcanqui province, where native communities living along the banks of Santiago River lack access to potable water, sewage, and electricity. This study aimed to analyse malaria's spatial, temporal, and climatic characteristics in Condorcanqui to guide future studies and prevention strategies.

Methods: A database provided by DIRESA-Amazonas was evaluated. Database included cases from 44 health facilities serving 112 native communities. According to the malaria control programs implemented in Peru, the study was divided into three periods: 2005-2010, 2011-2016, and 2017-2022. A Spearman correlation analysis was also conducted to assess the relationship between malaria incidence and climate variables.

Results: During the study periods, 10,632 cases were reported, including Plasmodium vivax (84.87%), Plasmodium falciparum (14.91%) and Plasmodium malariae (0.23%) infections. Annual incidence rates (AIRs) significantly varied across the study periods (p < 0.001). A significant reduction in malaria incidence occurred during the first period, largely attributed to PAMAFRO programme interventions. Subsequent periods, showed a gradual increase in cases, with a peak of P. vivax in 2019 and the reintroduction of P. falciparum. Males and individuals aged 0-11 years presented the greatest number of cases. Significant correlations were found between malaria incidence and the Oceanic Niño Index (ONI) at lag0 (ρ = 0.14, p = 0.037), corrected precipitation at lag1 (ρ = 0.16, p = 0.020), and minimum wind speed at lag1 (ρ = 0.15, p = 0.024).

Conclusions: Malaria incidence in Condorcanqui has increased over the last 5 years, driven by climatic influences such as the ONI, precipitation, and low wind speeds. Without immediate preventive efforts, cases are expected to continue rising. Effective control strategies must tackle the social, economic, and political issues that heighten vulnerability, such as poverty and limited healthcare access. Maintaining control initiatives and tailoring them to local needs will be essential for achieving long-term reductions of malaria in Peru.