Map of the study health facilities.

Provinces were colours according to their region: north (red), centre (green) or south (blue). White dots show the locations of the health facilities included in the study, with a zoom in to show the ones included in Magude and Matutuine districts. Maps used OpenStreetMap data, available under the Open Database License.

Flowchart of the P. falciparum samples and data from Magude and Matutuine districts collected in 2022.

Statistics of travel reports.

A) Pie chart showing the distributions of the travel destination provinces in sampled individuals from Maputo province (Magude and Matutuine). Colours show the provinces from blue (south) to red (north). B) Spatial connectivity based on travel history. Line widths are proportional to the number of travels reported from Maputo province to their destination province, with the same colors as in A. Maps used OpenStreetMap data, available under the Open Database License.

Sample size and characteristics of the P. falciparum clinical cases in Magude and Matutuine with travel history data.

Travel destinations among the 105 P. falciparum clinical cases in Magude and Matutuine that reported having travelled during the previous 28 days.

Provinces of the travel destinations reported (left column) and the total number of travels (and percentage) reported to each province (right column).

Convenience sampling from selected health facilities in 9 provinces: number of samples and patient characteristics.

Province: province of the health facilities from where the samples were collected. N: number of samples collected in each province. Mean age (SD): mean and standard deviation of the participant ages from each province. Female fraction (%): fraction of females of the participants from each province.

Genetic relatedness (identity-by-descent, IBD) of P. falciparum infections between regions in Mozambique.

A) Fraction (R) of IBD-related sample pairs (IBD>0.1 with p<0.05) within and between different provinces, represented in colours. B) Spatial genetic connectivity between provinces. Line widths and point sizes are proportional to R, and colours show the ranking in R values (from blue to red, using turbo colormap). C) R between and within different regions (south, centre and north), combining samples from centre and north (D) and across Magude and Matutuine districts (E). N=1467. Maps used OpenStreetMap data, available under the Open Database License.

p-values of IBD-relatedness results.

A) P-values of the deviation of the fraction of IBD-related pairs (IBD>0.1 with p<0.05) of the samples within and between different provinces with respect to the average across all pairs. B) The same, but comparing sample pairs within and across regions (south, centre and north). C) The same, but comparing sample pairs across south and centre/north. D) The same, but across Magude and Matutuine districts.

Genetic relatedness as a function of spatial distance.

A) Fraction of IBD-related pairs (using different thresholds of IBD (always with p<0.05), shown in different colours as a function of the pairwise geographical distance, using a range of distances from 100 km to 1,400 km (typically inter-province samples). B) The same as A but for distances between 20 km and 100 km (typically within the same province but distinct health facilities). C) the same but for distances between 0 (same household) and 20 km, which is impacted by the significantly higher fraction for cases from the same household. N=1467.

Distribution of importation probabilities by district.

Distribution of the individual probabilities of being imported for the studied clinical cases from Magude (orange) and Matutuine (blue) districts.

Travel destination (by province) of the imported cases reported in Magude and Matutuine.

Weighted number of cases: the total number of cases (weighted by their probability) imported from each province (n=200). Imported cases: the total number of cases classified as imported if P(imported)>50% (n=200). % cases with travel reports: The fraction of imported cases from each province with respect to the total number of cases reporting travel in the previous 28 days (n=105). % all reported: the total contribution of imported cases from each province with respect to all reported cases in the Maputo province (n=200). Imported to Magude: total of imported cases residing in Magude (n=27). Imported to Matutuine: total of imported cases residing in Matutuine (n=173).

Odds ratio statistics of factors associated with importation and travel.

Odds ratio of importation (A-B), reporting travel (C-D) and importation for cases with travel reports (E-F) for different factors in univariate (A, C and E) and multivariate (B, D and F) models, for all P. falciparum clinical cases recruited in Magude and Matutuine (n=200 for A-D, n=105 for E and F).

Distribution of importation probabilities using different combinations of factors.

Probability distributions of the clinical cases with travel reports of being imported, depending on the inclusion of factors included in the estimation. The black histogram (A) shows the estimations from the formula described in Methods sections, while the orange (B), purple (C) and green (D) distribution show the estimations when removing the genetic relatedness (R’), the travel duration (T) or the transmission intensity (PR) metrics respectively.

Importation probability statistics using different data sources in the estimations.

The weighted number of cases (second column, n=2007) and their percentages with respect to all mRDT+ cases with travel reports (third column, n=1057) and with respect to all studied cases (last column, n=2007)) obtained for different combinations of data sources (specified in the first column). R’: the estimation of probability of importation (see Methods) includes the R’ in the travel destination (fraction of samples from the travel destination province genetically related to the case) and origin (fraction of samples from the local province –Maputo-genetically related to the case). Otherwise, equal R’ is assumed between origin and travel destination. T: the estimation of probability of importation includes the metrics of the travel duration and time spent at home. Otherwise, equal time is assumed. PR: the mRDT positivity rates (PR) per province in children reported in the last Health Demographic Survey 2022-2023 is used as a proxy of transmission intensity for each province. Otherwise, equal PR is assumed.

Comparison of travel reports and genetic relatedness with Maputo province (local) and travel destination provinces.

The table shows the number of cases that reported (Yes) or not (No) a travel to each province (columns “Destination province”) and how many of these cases show a fraction of genetically related pairs (IBD >0.1 with p<0.05) higher when compared with the samples collected in Maputo province (third column) or when compared with the travel destination province (fourth column) (n=200). The p-value shows the result of a Chi-square consistency test under the hypothesis that the genetic relatedness with Maputo or the other province does not depend on whether a travel has been reported or not.

Factors associated with imported malaria among the 200 cases reported in Matutuine and Magude: distribution by malaria case classification (local vs imported) and odds ratios from univariate and multivariate logistic regression.

SD=standard deviation; GM=geometric mean; CI=confidence interval.

Factor association to travel.

Distribution of cases reporting and not reporting travel based on different factors and the statistical significance of the association of their odds ratio associated with travel. SD=standard deviation; GM=geometric mean; CI=confidence interval.

Factor association to importation conditioned to travel.

Distribution of cases reporting travel based on different factors and the statistical significance of the association of their odds ratio associated with importation. SD=standard deviation; GM=geometric mean; CI=confidence interval.