Background
The wilaya of Saïda, located in the semi-arid steppe of northwestern Algeria, comprises seven administrative communes distributed across a heterogeneous topography. Characterizing the long-term climatic trends and geographic setting of this region is essential background for interpreting the transmission dynamics of cutaneous leishmaniasis (CL) and other environmentally sensitive vector-borne diseases in the area.
Aims
This study aimed to (i) geographically characterize the seven communes of the wilaya of Saïda (Saïda City, Hassasna, Maamora, Skhouna, Balloul, Tircine, and Aïn Soltane), and (ii) analyze the 24-year (2002–2025) trends in temperature and precipitation across the region. Materials and Methods Geographic coordinates of the seven communes were determined and mapped, distinguishing the single urban commune (Saïda City, the wilaya capital) from the six rural communes. A continuous monthly series of mean temperature (°C) and total precipitation (mm) covering 288 months (January 2002–December 2025) was compiled and subjected to a systematic data-quality audit; two physically implausible monthly precipitation values and seven duplicate-flagged months were identified and excluded from the analytic series. Annual and seasonal climatology were described, and temporal trends were assessed using the Mann-Kendall test, Sen's slope estimator, and linear regression (slope with 95% confidence interval).
Results
The wilaya spans approximately 34.50–34.99°N and 0.15–0.85°E, located roughly 180 km southeast of Oran, with Skhouna representing the most geographically distant rural commune from the urban center. Annual mean temperature rose significantly over the study period (+ 0.103°C/year, 95% CI 0.053–0.153; p = 0.0028), corresponding to an approximate + 2.4°C increase between 2002 and 2025. Annual total precipitation showed a probable declining trend (− 6.1 mm/year, 95% CI − 11.7 to − 0.6; p = 0.043), representing roughly a one-third reduction in annual rainfall totals over the same period. The regional climate followed a classical semi-arid Mediterranean pattern, with hot, dry summers (24–28°C, < 20 mm/month) and cooler, comparatively wetter autumn–winter–spring months. These findings are significant beyond their descriptive value: the magnitude of the warming trend places Saïda among the more rapidly warming semi-arid zones of the Mediterranean basin, with plausible relevance to the seasonal activity window of phlebotomine sand fly vectors, while the locally-calibrated seasonal climatology established here provides, for the first time for this wilaya, a climatic reference against which the monthly CL reporting pattern can be meaningfully interpreted.
Conclusion
The wilaya of Saïda has undergone a statistically robust warming trend and a probable drying trend over the past 24 years, consistent with broader Mediterranean and North African climate observations. These geo-climatic findings offer practical applications for CL prevention: anchoring vector-control campaign timing to the pre-transmission warm season rather than the later diagnostic-peak months, supporting periodic reassessment of the transmission season's boundaries as warming continues, prioritizing surveillance resources geographically as reservoir habitat suitability shifts, and establishing a locally-validated baseline for detecting future climatic anomalies that may warrant heightened CL surveillance.
DA - 08/2026 DO - 10.21203/rs.3.rs-10482904/v1 LA - ENG M3 - Article N2 -Background
The wilaya of Saïda, located in the semi-arid steppe of northwestern Algeria, comprises seven administrative communes distributed across a heterogeneous topography. Characterizing the long-term climatic trends and geographic setting of this region is essential background for interpreting the transmission dynamics of cutaneous leishmaniasis (CL) and other environmentally sensitive vector-borne diseases in the area.
Aims
This study aimed to (i) geographically characterize the seven communes of the wilaya of Saïda (Saïda City, Hassasna, Maamora, Skhouna, Balloul, Tircine, and Aïn Soltane), and (ii) analyze the 24-year (2002–2025) trends in temperature and precipitation across the region. Materials and Methods Geographic coordinates of the seven communes were determined and mapped, distinguishing the single urban commune (Saïda City, the wilaya capital) from the six rural communes. A continuous monthly series of mean temperature (°C) and total precipitation (mm) covering 288 months (January 2002–December 2025) was compiled and subjected to a systematic data-quality audit; two physically implausible monthly precipitation values and seven duplicate-flagged months were identified and excluded from the analytic series. Annual and seasonal climatology were described, and temporal trends were assessed using the Mann-Kendall test, Sen's slope estimator, and linear regression (slope with 95% confidence interval).
Results
The wilaya spans approximately 34.50–34.99°N and 0.15–0.85°E, located roughly 180 km southeast of Oran, with Skhouna representing the most geographically distant rural commune from the urban center. Annual mean temperature rose significantly over the study period (+ 0.103°C/year, 95% CI 0.053–0.153; p = 0.0028), corresponding to an approximate + 2.4°C increase between 2002 and 2025. Annual total precipitation showed a probable declining trend (− 6.1 mm/year, 95% CI − 11.7 to − 0.6; p = 0.043), representing roughly a one-third reduction in annual rainfall totals over the same period. The regional climate followed a classical semi-arid Mediterranean pattern, with hot, dry summers (24–28°C, < 20 mm/month) and cooler, comparatively wetter autumn–winter–spring months. These findings are significant beyond their descriptive value: the magnitude of the warming trend places Saïda among the more rapidly warming semi-arid zones of the Mediterranean basin, with plausible relevance to the seasonal activity window of phlebotomine sand fly vectors, while the locally-calibrated seasonal climatology established here provides, for the first time for this wilaya, a climatic reference against which the monthly CL reporting pattern can be meaningfully interpreted.
Conclusion
The wilaya of Saïda has undergone a statistically robust warming trend and a probable drying trend over the past 24 years, consistent with broader Mediterranean and North African climate observations. These geo-climatic findings offer practical applications for CL prevention: anchoring vector-control campaign timing to the pre-transmission warm season rather than the later diagnostic-peak months, supporting periodic reassessment of the transmission season's boundaries as warming continues, prioritizing surveillance resources geographically as reservoir habitat suitability shifts, and establishing a locally-validated baseline for detecting future climatic anomalies that may warrant heightened CL surveillance.
PB - Springer Science and Business Media LLC PY - 2026 SP - 1 EP - 21 TI - Long-Term Climatic Trends (Temperature, Precipitation) and Cutaneous Leishmaniasis Risk Across Seven Communes of Saïda, Northwestern Algeria (2002–2025) UR - https://assets-eu.researchsquare.com/files/rs-10482904/v1_covered_ec2deff0-28d1-4135-b726-50de7c5c3361.pdf?c=1786098547 ER -