Background/Objectives: Cutaneous leishmaniasis (CL) remains a major public health and economic challenge in Morocco, where its transmission dynamics are increasingly influenced by climatic variability. This study aimed to evaluate the impact of meteorological factors on CL incidence in the province of Essaouira, a high-incidence region, to identify the environmental drivers behind recent epidemic trends. Methods: Epidemiological data (N = 834 cases) were collected from the Hygiene and Health Laboratory of Essaouira for the period between January 2014 and December 2023. Climatic variables were obtained from the Moroccan Directorate of National Meteorology. Data were analyzed at annual, seasonal, and monthly scales using the Spearman rank correlation in R 4.5.0 software to account for non-normal distributions and non-linear associations. Results: CL incidence remained stable from 2014 to 2021 before an unprecedented surge in cases during 2022–2023. Annual analysis indicated that warm and dry years pose a higher risk, with incidence positively correlated with temperatures and negatively associated with humidity and precipitation. Monthly results identified a biphasic regulatory mechanism: a winter hydric constraint phase with strong negative correlations with January rainfall and humidity (p < 0.05), followed by a summer thermal promotion phase where minimum temperature (T_min) emerged as the dominant driver (rho = 0.53), peaking in September (rho = 0.59). Conclusions: Our findings confirm the significant influence of climatic factors on CL incidence through complex seasonal dynamics. These results highlight the necessity of integrating high-resolution meteorological monitoring and predictive modeling into public health surveillance to anticipate future outbreaks in the context of increasing Mediterranean aridification.

The experimental study of the complexation of the amino acids (glycine, alanine, L‐canavanine, and L‐arginine) with the zinc ion Zn(II) was completed, and a computational study employing density functional theory (DFT) with implicit solvation was conducted to investigate the protonation behavior and complexation of these amino acids. The analysis of proton affinities (PA) and charges identifies the carboxyl group as the primary deprotonation and metal‐binding site. For glycine and alanine, stable bidentate complexes are formed via the carboxyl oxygen and amine nitrogen. A key finding is the distinct behavior of L‐canavanine compared to L‐arginine. The existence of a supplementary oxygen atom in L‐canavanine's guanidyl group reduces its PA, allowing for tridentate coordination with Zn(II). Structural optimizations reveal that Zn(II) complexes exhibit shorter, more rigid metal–ligand bonds and higher formation enthalpies than Hg(II) complexes, indicating greater thermodynamic stability. The observed geometric distortions in octahedral complexes are rationalized by ligand denticity and coordination sphere homogeneity. These theoretical results on binding energetics, bond lengths, and coordination modes are in strong agreement with available experimental data, validating our approach for predicting the environmental reactivity of these biomolecules with toxic metal pollutants.