Spatiotemporal dynamics and ecological determinants of cutaneous Leishmaniasis in Errachidia Province, southeastern Morocco: A 16-year municipality-level analysis with SARIMA forecasting.
Aug 2026· Parasitology international· Vol 116, pp.
103363
· 0 citations
Medicine
TL;DR
Overall, the incidence showed marked temporal fluctuations but demonstrated a general decreasing trend over the study period, and higher incidence was associated with low- to medium-altitude municipalities, while no significant association was observed with poverty or vulnerability indices.
Abstract
Leishmaniasis is a vector-borne parasitic disease transmitted by female sandflies of the genus Phlebotomus and affects approximately 1.2 million people annually in more than 90 countries worldwide. Morocco remains one of the most affected countries in North Africa, where the disease continues to represent a major public health concern. This study aimed to analyze the spatial and temporal trends of leishmaniasis incidence across all municipalities of Errachidia Province between 2010 and 2025 and to assess the influence of ecological, demographic, and socio-economic factors on its distribution. Also, the study aimed to predict the monthly CL cases using the Seasonal Autoregressive Integrated Moving Average (SARIMA) model. Epidemiological data on parasitologically confirmed cases obtained from the Errachidia Provincial Health Delegation were processed using geographic information system (GIS) tools and statistical methods to explore spatial patterns and correlations with environmental and socio-demographic variables. The models are trained and evaluated using monthly CL cases collected from 2010 to 2025, with the optimal model selected based on Akaike Information Criterion (AIC). During 16-years study period, 7034 cases were recorded in Errachidia Province, with the highest incidence reported in 2010 (860 cases per 100,000 inhabitants). Overall, the incidence showed marked temporal fluctuations but demonstrated a general decreasing trend over the study period. A pronounced spatial heterogeneity was observed between rural municipalities (Sid Ali, Melaab, and Ferkla) and urban municipalities (Errachidia, Arfoud, and Goulmima) (p < 0.01). The disease was slightly more frequent in females (54.41%) than in males (45.59%), and a significant difference was observed among age groups (p = 0.019), with the 0-9 and 10-19-year groups being the most affected. Seasonal analysis revealed a peak incidence during winter. In addition, higher incidence was associated with low- to medium-altitude municipalities, while no significant association was observed with poverty or vulnerability indices. The SARIMA (0,0,1)12 model demonstrated the best predictive performance. These findings highlight the heterogeneity and ecological determinants of leishmaniasis in southeastern Morocco and may support targeted surveillance and control strategies in high-risk areas.
Background: Zoonotic cutaneous leishmaniasis (ZCL) caused by Leishmania major remains a major public health concern in Morocco, especially in certain semi-arid and pre-Saharan regions where ecological conditions favor transmission. In recent decades, the epidemiology of ZCL has evolved significantly, particularly in its temporal patterns and the persistence of transmission in major endemic provinces. In this study, we adopted a retrospective observational approach to explore the long-term spatiotemporal dynamics of ZCL across nine endemic provinces in Morocco and to assess its potential environmental, socio-economic, and demographic determinants using a descriptive analytical framework. Principal findings: A total of 58,880 ZCL cases were reported during the study period between 1995 and 2022, with incidence peaks observed in 2010 and 2018, reflecting cyclical epidemic dynamics. The Drâa-Tafilalet region accounted for the highest disease burden, with Zagora province identified as the main epidemiological hotspot. Children aged ≤10 represented the most affected age group (40.8% of total cases), whereas infection rates did not differ significantly between the sexes (female-to-male ratio = 1.17). Higher incidence was observed in hyper-arid provinces characterized by sandy-clay-loam soils. However, incidence was not statistically correlated with either environmental or social variables (p > 0.05). Conclusions: ZCL remains endemic in Morocco, with persistent hotspots linked to specific ecological contexts. These findings highlight the importance of geographically targeted surveillance and control measures to support the integration of environmental indicators into risk monitoring and early-warning systems for leishmaniasis.
C. Harkat, Denis Sereno, Oussama Rida et al.· Parasite· 0 citations
Background Rickettsioses are caused by obligate intracellular bacteria of the order Rickettsiales, which includes several genera such as Rickettsia, Orientia, Anaplasma, Ehrlichia, Neoehrlichia, and Neorickettsia, and are significant yet under-recognised vector-borne febrile illnesses in Sri Lanka. Despite being a notifiable disease, gaps in understanding its spatial and temporal distribution hinder effective control and prevention. Therefore, the present study aimed at determining long-term epidemiological trends and environmental determinants of rickettsioses incidence in Sri Lanka between 2009 and 2023. Methods A retrospective ecological analysis was conducted using weekly rickettsioses case reports obtained from the Epidemiology Unit of the Ministry of Health, Sri Lanka, covering all 25 districts over the period 2009–2023. Mid-year district population data and district land area were retrieved from the Department of Census and Statistics to calculate incidence rates per 100,000 population. Meteorological variables (mean, maximum, and minimum temperatures; total rainfall; and mean relative humidity) were retrieved using NASA POWER satellite-derived datasets. A Zero-Adjusted Gamma (ZAGA) model within the Generalized Additive Model for Location, Scale, and Shape (GAMLSS) framework was utilized to estimate the influence of climatic and spatial variables on incidence rates, with environmental predictors selected based on a priori biological hypotheses regarding vector ecology. Results Between 2009 and 2023, a total of 18,486 rickettsioses cases were reported. The highest case burden was detected in Jaffna (n = 7,080), followed by Kandy (n = 1,363), Badulla (n = 1,319), Nuwara Eliya (n = 1,141), Hambantota (n = 1,066), and Monaragala (n = 1,008). The higher incidence rates were concentrated in the Northern and Central highland districts compared to low-incidence regions in the Western and Southern provinces. Temporal analysis indicated seasonal peaks coincide with monsoonal rainfall, with a rise of cases during January to February and September to November. The GAMLSS model demonstrated that mean temperature, relative humidity, and rainfall significantly influenced incidence rates (P < 0.05), with high humidity and post-monsoonal rainfall correlating with increased risk. Spatial predictors (latitude and longitude) also contributed to explaining distribution patterns, highlighting localized ecological drivers. Conclusions This study provides the first comprehensive nationwide analysis of rickettsioses incidence in Sri Lanka, highlighting firm spatial heterogeneity and clear climatic associations. The findings emphasize the necessity of targeted surveillance and early diagnostic capacity in high-burden districts, particularly Jaffna and the central highlands. Integrating climatic data into surveillance systems may improve early warning and outbreak preparedness. Improved diagnostic availability at regional hospitals and enhanced physician awareness are essential to reduce under-diagnosis and guide timely interventions.
N. Gunathilaka, D. Jayakody, Iranga Dilshan· PLoS ONE· 0 citations
ABSTRACT Analyses based on biomes provide a less fragmented view than usual studies and help the understanding of epidemiological characteristics from different perspectives. We describe the temporal trends and spatial distribution of American cutaneous leishmaniasis (ACL) and visceral leishmaniasis (VL) in Brazilian biomes, from 2007 to 2020. This ecological survey used data from the Brazilian Notifiable Diseases Information System. The Prais–Winsten method was used for temporal analyses. ACL and VL incidences were calculated based on sex and age groups, relative risk considering these two variables, and mortality, lethality, cure, and treatment abandonment rates per biome. The Amazon, Atlantic Forest, Cerrado, and Caatinga biomes showed a decreasing temporal trend, varying from −1% to −3% for ACL and VL, respectively. Other biomes showed a stationary temporal trend for both diseases. VL had a similar transmission profile in all biomes, affecting children aged 0–4 years regardless of sex. In contrast, ACL mainly affected older adults, except in the Amazon and Pampa, where working-age males were most commonly affected. In all biomes, being a man constituted a risk factor for acquiring these diseases, abandoning treatment, and dying, whereas being a woman configured a factor that favored cure and protected against lethality. Our findings showed a decrease in ACL and VL incidence in most biomes and a stable incidence in other biomes. The results of our study showed that the distinct transmission profiles of ACL and VL have persisted across different biomes with minute differences.
G. Ferreira, L. A. Melchior, A. F. Brilhante· Revista do Instituto de Medi...· 0 citations
Diseases caused by mosquito-borne pathogens have spread globally, posing a growing threat to public health. This study aimed to evaluate the distribution of breeding sites and properties that were positive for the presence of Aedes aegypti and Aedes albopictus in the health macro-regions of Santa Catarina, between 2013 and 2023, seeking to identify seasonal and geographic occurrence patterns to support vector control strategies. This is an ecological study with secondary data provided by the Diretoria de Vigilância Epidemiológica do Estado de Santa Catarina (DIVE, State of Santa Catarina Epidemiological Surveillance Directorate), tabulated by year and macro-region, including mosquito samples grouped by property and breeding site category. Kruskal-Wallis tests were performed, followed by Dwass-Steel-Critchlow-Fligner multiple comparisons - DSCF. The analysis revealed that 5.78% of the populations were of Aedes albopictus and 94.22% of Aedes aegypti. The macro-region with the most Aedes aegypti populations was the Grande Oeste, and the most critical year was 2023. The Planalto Norte and Nordeste had the highest concentration of Aedes albopictus, peaking in 2022. Commercial and residential properties were the most affected. The disparities observed between macro-regions, years, and species suggest that regional and temporal factors play an important role in the distribution of mosquitoes.
C. P. Vieira, Millena Fernandes, R. K. Leal et al.· Anais da Academia Brasileira...· 0 citations
INTRODUCTION
Brucellosis is a bacterial zoonotic disease transmitted through contact with infected animals or unpasteurized products. Endemic in Iran, it causes fever, fatigue and muscle pain, posing significant public health and economic challenges. This study aims to investigate the factors influencing preventive behaviours against brucellosis in Hamadan Province, utilizing the PEN-3 model to explore cultural and social dynamics, alongside Geographic Information System (GIS) technology for spatial analysis of disease incidence.
METHODS
This study was conducted in two sequential phases. In the first phase, with the aim of identifying geographical hotspots of human brucellosis, data on all confirmed cases reported in Hamadan Province between 2016 and 2023 were extracted from the national communicable disease surveillance system. Spatial analysis was carried out using ArcGIS version 10.8.2, and significant high-risk clusters were identified through the Getis-Ord Gi* statistical method. Based on the spatial clustering results, Kabudarahang County was selected as the study site for the second phase. In the second phase, a case-control study was conducted in 2024 in comprehensive health centers within Kabudarahang County. The study sample included 306 participants, comprising 102 cases (individuals with confirmed brucellosis) and 204 controls (healthy individuals). Brucellosis diagnosis was established according to the Iranian Ministry of Health's standard case definition, including positive serological tests such as Wright (≥ 1:80), 2ME (≥ 1:40), or Coombs-Wright. Data collection was performed using a researcher-developed questionnaire grounded in the PEN-3 cultural model, encompassing demographic characteristics, knowledge about brucellosis, perceptions, enabling factors, nurturing influences and preventive behaviours. The questionnaire's content validity was confirmed through expert panel evaluation using CVI and CVR indices, and internal consistency was assessed using Cronbach's alpha. Data were analyzed using Stata version 17.
RESULTS
The study found that brucellosis was most prevalent in rural areas and among men, with an adjusted incidence risk of 8.95 per 10,000 people. Kabudarahang County was identified as the primary hotspot, with an incidence risk of 24.99 per 10,000 people. Protective factors included being female (OR = 0.44), higher education (OR = 0.41), better economic status (OR = 0.36) and higher preventive behaviour scores (OR = 0.92). Risk factors included working in livestock (OR = 5.40) or agriculture (OR = 2.14), consuming local dairy products (OR = 2.98), contact with livestock at home (OR = 6.56) and family history of brucellosis (OR = 11). Linear regression analysis indicated that knowledge, perceptions, enablers and nurturers explained 34% of preventive behaviours.
CONCLUSION
This study emphasizes the importance of education and raising knowledge to reduce the prevalence of brucellosis. The findings suggest that effective prevention of this disease requires attention to the complex interaction of demographic, educational and behavioural factors. Using comprehensive models such as the PEN-3 model can help better understand the cultural and social determinants of health behaviours. Policymakers should develop and implement comprehensive educational and preventive programs that specifically address the needs and conditions of rural communities and individuals at risk.
Mahsa Sarvi, Babak Moeini, Amin Doosti-Irani et al.· Zoonoses and Public Health· 0 citations
Freshwater snails of the genus
Biomphalaria
transmit
Schistosoma mansoni
(intestinal schistosomiasis),
Bulinus
species transmit
S. haematobium
(urogenital schistosomiasis), and
Lymnaea
species transmit
Fasciola
spp. (fascioliasis). These diseases are of major public health and veterinary concern in sub-Saharan Africa. In Uganda's Lango subregion, schistosomiasis remains endemic despite control efforts, yet comprehensive spatial and ecological analyses of snail intermediate host distributions are lacking. This study employed geostatistical approaches to identify high-density snail habitats and sites where schistosome cercarial shedding was detected (as a proxy for potential infection, without molecular confirmation) to inform further surveillance and consideration of targeted control strategies.
A cross-sectional study was conducted during the dry and rainy seasons of 2023 across 26 georeferenced sites in Lira and Kole districts. Freshwater snails were collected using standardized methods and identified morphologically using Brown (1994) and Mandahi-Barth (1988) keys. Cercarial shedding tests determined patent infection status but could not definitely distinguish human-infective from non-human schistosome species without molecular confirmation. Physicochemical parameters (pH, salinity, total dissolved solids, dissolved oxygen, temperature, and conductivity) and ecological variables were measured. Spatial analysis included Moran’s I for autocorrelation, Getis-Ord Gi* for hotspot detection, and inverse distance weighting for interpolation. Generalized linear mixed models with spatial random effects were used to assess predictors of snail prevalence and density, compared with non-spatial models using the Akaike Information Criterion. Dry and rainy season data were treated as separate observations from the same sites (
n
= 52 site-season observations), with site included as random effect to account for repeated measures.
A total of 4802 snails from 13 species were collected, with
Biomphalaria choanomphala
(25.8%,
n
= 1241) being most abundant.
Bulinus africanus
(17.7%,
n
= 852) and
Lymnaea natalensis
(10.6%,
n
= 510) were also abundant. Significant spatial clustering was detected for
B. choanomphala
(Moran’s
I
= 0.32,
p
= 0.004) and
B. sudanica
(Moran’s
I
= 0.24,
p
= 0.018). Three density hotspots and sites where cercarial shedding was detected (descriptive only given the small number of infected snails) were identified, primarily in rice paddies and swamps near human settlements. Overall patent infection rate (based on cercarial shedding) was 0.15% (5/3404 tested snails). Species-specific rates were
B. choanomphala
0.16% (2/1,241),
B. sudanica
0.13% (1/749), and
B. africanus
0.23% (2/852). No schistosome-like infections were detected in
Lymnaea
snails or other genera. Spatial GLMMs outperformed non-spatial models (ΔAIC = 12.7–15.3), revealing significant effects of salinity (odds ratio = 0.21,
p
< 0.001), total dissolved solids (
β
= − 0.03,
p
= 0.002), dissolved oxygen (
β
= 0.54,
p
= 0.003), and anthropogenic activities. Spatial random effects accounted for 18–24% of residual variation.
This study demonstrates the added value of geostatistical methods in identifying snail intermediate host clusters and sites with detected schistosome-like infections. The integration of spatial analysis with ecological modeling provides a robust framework to guide further surveillance and consideration of targeted snail control interventions. Our findings suggest that focused surveillance in identified high-density areas, integration of spatial risk maps into district health planning, and community engagement in modifying high-risk water contact sites could be considered to help reduce schistosomiasis transmission in the Lango subregion. These suggestions require validation through longitudinal studies before implementation at scale.
John Paul Byagamy, Robert Opiro, Margaret Nyafwono et al.· Parasites & Vectors· 0 citations
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