Treatment-seeking time and its determinants among patients with confirmed malaria in Thailand: a national surveillance analysis, 2012–2024

Timely treatment of malaria is critical to preventing severe disease and onward transmission. However, treatment-seeking behavior varies across populations and geographic settings. This study examined treatment-seeking time and its determinants among patients with confirmed malaria in Thailand using national surveillance data. A retrospective analysis was conducted using surveillance data from laboratory-confirmed malaria cases recorded in Thailand’s Electronic Malaria Information System (eMIS) from January 2012 to December 2024. The outcome was treatment-seeking time, defined as the number of days between the self-reported date of symptom onset and the date of confirmed malaria diagnosis recorded in the surveillance system. Descriptive statistics summarized treatment-seeking delays, while geographic variation was visualized using choropleth maps. Factors associated with treatment-seeking time were examined using negative binomial regression, with incidence rate ratios (IRRs) and 95% confidence intervals (CIs) reported. A total of 127,242 confirmed malaria cases were analyzed. The majority were male (68.6%) and aged 15 years or older (73.5%), with Plasmodium vivax accounting for 75.0% of infections. The median treatment-seeking time was 2 days (interquartile range [IQR]: 1–3 days). Delays were longer among adults aged 15–34 years (IRR: 1.03; 95% CI 1.01–1.05) and ≥ 35 years (IRR: 1.03; 95% CI 1.01–1.05) compared with children under five years. Longer delays were also observed among long-term migrants (IRR: 1.04; 95% CI 1.03–1.06), short-term migrants (IRR: 1.06; 95% CI 1.04–1.08), and infections due to P. falciparum (IRR: 1.07; 95% CI 1.05–1.08), P. knowlesi (IRR: 1.19; 95% CI 1.12–1.26), and other species (IRR: 1.22; 95% CI 1.16–1.27), relative to P. vivax . Treatment-seeking time was longer in provinces classified as elimination-phase “clear-up” zones (IRR: 1.17–1.20) than in active transmission areas, whereas imported cases had shorter treatment-seeking times than indigenous cases (IRR: 0.96–0.98), likely reflecting differences in surveillance and case detection pathways. Western border provinces with historically high malaria burden showed relatively shorter treatment-seeking times. Most individuals with confirmed malaria in Thailand were diagnosed within a relatively short period following symptom onset, although delays persisted among migrants, individuals with non- P. vivax infections, and residents of elimination-phase settings. Targeted interventions to improve access to care and awareness among mobile populations and low-transmission areas could further reduce treatment-seeking delays and support Thailand’s malaria elimination goals.