Linking climate to incidence of zoonotic cutaneous leishmaniasis (L. major) in pre-Saharan North Africa

The Impact of Climatological Factors on the Incidence of Cutaneous Leishmaniasis (CL) in Colombian Municipalities from 2017 to 2019

Cutaneous leishmaniasis (CL) is a zoonotic disease caused by protozoa of the Leishmania genus, transmitted by vectors from the Phlebotominae subfamily. The interaction between the vector, reservoir, and parasite is susceptible to climate change. This study explores how temperature and rainfall influenced the incidence of CL in 15 Colombian municipalities between 2017 and 2019. Epidemiological data were obtained from Colombia's Instituto Nacional de Salud, while climatological data came from the Instituto de Hidrología, Meteorología y Estudios Ambientales. Using Spearman's rank correlation coefficient, we examined the relationships between monthly climatic variables and the cumulative incidence of CL, considering various lag times. The data were further analyzed using Locally Weighted Scatterplot Smoothing (LOWESS). Our findings reveal both significant positive and negative correlations, depending on locality and climate variables. LOWESS analysis indicates that while rainfall-related incidence remains stable, temperature impacts incidence in a parabolic trend. This study underscores the significant yet complex influence of climatic factors on CL incidence. The insights gained could aid public health efforts by improving predictive models and crafting targeted interventions to mitigate the disease's impact, particularly in regions vulnerable to climate variability.

Epidemiological survey, molecular profiling and phylogenetic analysis of cutaneous leishmaniasis in Khyber Pakhtunkhwa, Pakistan

BACKGROUND

Cutaneous leishmaniasis (CL), an emerging vector-borne ailment in Khyber Pakhtunkhwa (KPK), Pakistan, exhibits diverse spread patterns and outbreaks.

METHODS

To comprehend its epidemiology and identify parasite species, we conducted an active survey on suspected CL cases (n=8845) in KPK.

RESULTS

Microscopy and internal transcribed spacer-1 PCR-restriction fragment length polymorphism (RFLP) molecular techniques detected Leishmania spp. in blood samples. Phylogenetic analysis gauged genetic affinities with other areas. District Bannu displayed the highest CL impact (14.58%), while Swat had the lowest impact (4.33%) among cases. Annual blood examination rate, parasite incidence and slide positivity rate were 4.96 per 1000 people, 0.0233 and 0.047%, respectively. CL infections were prevalent in 1- to 20-y-olds, with males (57.17%) more vulnerable than females (42.82%). Single lesions occurred in 43.73% of patients, while 31.2% people had two lesions, 17.31% had three lesions and 7.74% had more than three lesions. Most had sand-fly exposure but lacked preventive measures like repellents and bed nets. Leishmania tropica was confirmed via RFLP analysis in amplified samples. Phylogenetic analysis unveiled genetic parallels between L. tropica of KPK and isolates from China, Iran, Afghanistan, India, Syria and Morocco.

CONCLUSIONS

Urgent comprehensive control measures are imperative. Early detection, targeted interventions and raising awareness of CL and sand-fly vectors are vital for reducing the disease's impact. International collaboration and monitoring are crucial to tackle Leishmania spp.'s genetic diversity and curtail its cross-border spread.

Human Cutaneous Leishmaniasis in North Africa and Its Threats to Public Health: A Statistical Study Focused on Djelfa (Algeria)

Cutaneous leishmaniasis, the most common form of leishmaniasis, causes long-term skin lesions on exposed areas of the skin. It is caused by a protozoan parasite belonging to the genus Leishmania and is transmitted via infected phlebotomine sand flies. In North Africa, particularly Algeria, the disease represents a major public health problem. This retrospective study, which focuses on the agropastoral region of Djelfa (central Algeria) during a period of 16 years, from 2006 to 2021, is part of the surveillance of cutaneous leishmaniasis to identify the key factors favouring its probable spread. The analyzed data reveal that this disease is more prevalent in male patients (53.60%) and is highly widespread in this vast area of 66,415 km2 with a total of 3864 CL cases, reaching a peak of 1407 cases in 2006. Statistically, the Pearson correlation validated by the p-value shows, in an original and sometimes unexpected way, that certain factors, such as temperature linked to climate change, are playing a significant role in the probable spread of the disease in Djelfa and its surrounding regions. The concentration of the population in some specific rural areas with limited or nonexistent access to public health services is another potential factor in disease transmission. The results were highlighted by a significant correlation coefficient (r=0.66) with a p-value less than 0.01. While there is currently no vaccine or prophylactic drug available, our research represents a preliminary approach that addresses various epidemiological aspects of the disease. This paves the way for a proactive preventive strategy involving the control of vector-borne diseases.

Climate change and cutaneous leishmaniasis in the province of Ghardaïa in Algeria: A model-based approach to predict disease outbreaks

BACKGROUND

Cutaneous leishmaniasis (CL) is a vector-borne disease prevalent in Algeria since 2000. The disease has significant impacts on affected communities, including morbidity and social stigma.

OBJECTIVE

Investigate the association between environmental factors and the incidence of CL in the province of Ghardaïa and assess the predictive capacity of these factors for disease occurrence.

DESIGN

Retrospective SETTING: The study area included both urban and rural communities.

METHODS

We analyzed a dataset on CL in the province of Ghardaïa, Algeria, spanning from 2000 to 2020. The dataset included climatic variables such as temperature, average humidity, wind speed, rainfall, and the normalized difference vegetation index (NDVI). Using generalized additive models, we examined the relationships and interactions between these variables to predict the emergence of CL in the study area.

MAIN OUTCOME MEASURES

The identification of the most significant environmental factors associated with the incidence and the predicted incidence rates of CL in the province of Ghardaïa, Algeria.

SAMPLE SIZE AND CHARACTERISTICS

252 monthly observations of both climatic and epidemiological variables.

RESULTS

Relative humidity and wind speed were the primary climatic factors influencing the occurrence of CL epidemics in Ghardaïa, Algeria. Additionally, NDVI was a significant environmental factor associated with CL incidence. Surprisingly, temperature did not show a strong effect on CL occurrence, while rainfall was not statistically significant. The final fitted model predictions were highly correlated with real cases.

CONCLUSION

This study provides a better understanding of the long-term trend in how environmental and climatic factors contribute to the emergence of CL. Our results can inform the development of effective early warning systems for preventing the transmission and emergence of vector-borne diseases.

LIMITATIONS

Incorporating additional reservoir statistics such as rodent density and a human development index in the region could improve our understanding of disease transmission.

Time series analysis of cutaneous leishmaniasis incidence in Shahroud based on ARIMA model

BACKGROUND

Leishmaniasis is a zoonotic disease and Iran is one of the ten countries with has the highest estimated cases of leishmaniasis. This study aimed to determine the time trend of cutaneous leishmaniasis (CL) incidence using the ARIMA model in Shahroud County, Semnan, Iran.

METHODS

In this study, 725 patients with leishmaniasis were selected in the Health Centers of Shahroud during 2009-2020. Demographic characteristics including; history of traveling, history of leishmaniasis, co-morbidity of other family members, history of treatment, underlying disease, and diagnostic measures were collected using the patients' information listed in the Health Ministry portal. The Box-Jenkins approach was applied to fit the SARIMA model for CL incidence from 2009 to 2020. All statistical analyses were done by using Minitab software version 14.

RESULTS

The mean age of patients was 28.2 ± 21.3 years. The highest and lowest annual incidence of leishmaniasis were in 2018 and 2017, respectively. The average ten-year incidence was 132 per 100,000 population. The highest and lowest incidence of the disease were 592 and 195 for 100,000 population in the years 2011 and 2017, respectively. The best model was SARIMA (3,1,1) (0,1,2)₄ (AIC: 324.3, BIC: 317.7 and RMSE: 0.167).

CONCLUSIONS

This study suggested that time series models would be useful tools for predicting cutaneous leishmaniasis incidence trends; therefore, the SARIMA model could be used in planning public health programs. It will predict the course of the disease in the coming years and run the solutions to reduce the cases of the disease.

Time series analysis of leishmaniasis incidence in Sri Lanka: evidence for humidity-associated fluctuations

Leishmaniasis is a vector-borne disease of which the transmission is highly influenced by climatic factors, whereas the nature and magnitude differ between geographical regions. The effects of climatic variables on leishmaniasis in Sri Lanka are poorly investigated. The present study focused on time-series analysis of leishmaniasis cases reported from Sri Lanka with selected climatic variables. Variance stabilized time series of leishmaniasis patients of entire Sri Lanka and major districts from 2014 to 2018 was fitted to autoregressive integrated moving average (ARIMA) models. All the possible models were generated by assigning different values for autoregression and moving average terms using a function written in R statistical program. The top ten models with the lowest Akaike information criterion (AIC) values were selected by writing another function. These models were further evaluated using RMSE and MAPE error parameters to select the optimal model for each area. Cross-autocorrelation analyses were performed to assess the associations between climate and the leishmaniasis incidence. Most associated lags of each variable were integrated into the optimal models to determine the true effects imposed. The optimal models varied depending on the area. SARIMA (0,1,1) (1,0,0)₁₂ was optimal for the country level. All the forecasts were within the 95% confidence intervals. Humidity was the most notable factor associated with leishmaniasis, which could be attributed to the positive impacts on sand fly activity. Rainfall showed a negative impact probably as a result of flooding of sand fly larval habitats. The ARIMA-based models performed well for the prediction of leishmaniasis in the short term.

Seasonal Patterns of Zoonotic Cutaneous Leishmaniasis Caused by L. major and Transmitted by Phlebotomus papatasi in the North Africa Region, a Systematic Review and a Meta-Analysis

BACKGROUND

In North African countries, zoonotic cutaneous leishmaniasis (ZCL) is a seasonal disease linked to Phlebotomus papatasi, Scopoli, 1786, the primary proven vector of L. major dynamics. Even if the disease is of public health importance, studies of P. papatasi seasonal dynamics are often local and dispersed in space and time. Therefore, a detailed picture of the biology and behavior of the vector linked with climatic factors and the framework of ZCL outbreaks is still lacking at the North African countries' level. Our study aims to fill this gap via a systematic review and meta-analysis of the seasonal incidence of ZCL and the activity of P. papatasi in North African countries. We address the relationship between the seasonal number of declared ZCL cases, the seasonal dynamic of P. papatasi, and climatic variables at the North African region scale.

METHODS

We selected 585 publications, dissertations, and archives data published from 1990 to July 2022. The monthly incidence data of ZCL were extracted from 15 documents and those on the seasonal dynamic of P. papatasi from 11 publications from four North African countries.

RESULTS

Our analysis disclosed that for most studied sites, the highest ZCL incidence is recorded from October to February (the hibernal season of the vector), while the P. papatasi density peaks primarily during the hot season of June to September. Overall, at the North African region scale, two to four months laps are present before the apparition of the scars reminiscent of infection by L. major.

CONCLUSIONS

Such analysis is of interest to regional decision-makers for planning control of ZCL in North African countries. They can also be a rationale on which future field studies combining ZCL disease incidence, vector activity, and climatic data can be built.

A Community Based Survey of Knowledge, Attitudes, and Practices Concerning Leishmaniasis in Central Morocco

Leishmaniasis is a major health problem caused by a protozoan of the genus Leishmania, most commonly transmitted by infected female sand flies. Intersectoral collaboration is essential for the implementation of integrated vector management control with community participation. The present study aims to evaluate the knowledge, attitude and practices of the population toward leishmaniasis in central Morocco. A quantitative cross-sectional study was conducted using an administered questionnaire assisted by health professionals, on 750 people in the Marrakech Safi, endemic region of cutaneous leishmaniasis (CL). Of those, 702 agreed to be recruited for our study, of which 63,5% were women, 48,1% were aged between 18 and 40 years, and more than half of the participants (60%) were from rural areas. Overall, the knowledge, attitude and practices (KAPs) for leishmaniasis are too poor for more than 85% of the population in the study area. Basic knowledge and perceptions of leishmaniasis were good for 14,6% of respondents. While, 4,5% of the members had good knowledge of CL, only 0,7% had good level of knowledge about vesciral leishmaniasis (VL). Furthermore 3,7% of those polled have favorable attitudes and preventive practices. No association was found between knowledge and age, province or occupation. However, rural residents were four times more likely than urbain residents to have good basic knowledge (ORA = 4,74; CI95%: 1,04 -22,05). In addition, the female gender also has the chance to possess good basic knowledge and perceptions 3 times more than the men (ORA = 3,18; CI95%: 1,16 -8,69). The low level of KAPs regarding leishmaniasis proves the lack of community participation in the fight against leishmaniasis in central Morocco.

Ecological Survey of the Peridomestic Sand Flies of an Endemic Focus of Zoonotic Cutaneous Leishmaniasis in the South-East of Morocco

Leishmaniasis is a parasitosis caused by parasites of the genus Leishmania and is transmitted by Phlebotominae sand flies. An entomological survey was carried out in different localities of Zagora Province. Our work allowed us to establish an inventory of sand flies to study potential vectors of leishmaniasis and to compare the composition and the specific abundance of different endemic stations. The sand flies were collected using CDC miniature light traps during the month of July 2019 in the ten studied villages. The results indicate the presence of thirteen species, belonging to the genera Phlebotomus and Sergentomyia. Phlebotomus papatasi was the predominant species (46.65%) followed by Ph. alexandri (17%), Ph. longicuspis (11.55%), Ph. bergeroti (1.53%) and Ph. sergenti (1.27%). Phlebotomus kazeruni (0.03%) was rare, and only one female was captured in Ifred. Sergentomyia schwetzi (8.69%) was the most prevalent species in the Sergentomyia genus followed closely by Se. fallax (6.84%). Sergentomyia africana was present with a proportion of (3.86%) followed by Se. clydei (1.96%). Sergentomyia dreifussi (0.46%), Se. antennata (0.08%), and Se. minuta (0.08%) were very limited. Phlebotomus papatasi, Ph. alexandri, Ph. bergeroti, Ph. longicuspis, Ph. sergenti, Se. schwetzi, Se. clydei, and Se. fallax are constant species, being present at least in 50% of the stations (occurrence> 50%). Common species (25%–49%) were Se. minuta and Se. africana and rare species were Ph. kazeruni and Se. antennata with a very limited distribution (occurrence <12%). The greatest species richness was found in Ksar Mougni and Ifred with the occurrence of 11 species, but overall, it was high (>9 species) in most of the villages. The Shannon–Wiener index was high (H′ > 1) in eight localities (Ksar Mougni, Tassaouante, Bleida, ZaouiteLeftah, Ifred, Timarighine, Ait Oulahyane, and Ait Ali Ouhassou). The high value of this index is in favor of the ZaouiteLeftah locality (Shannon–Wiener index = 1.679) which is explained by the presence of a stand dominated by Ph. papatasi. In order to avoid exposure to infections, a good epidemiological surveillance and vector with rodent control measures must be well maintained. Awareness campaigns are also required and must be conducted for better knowledge of the disease.

A recent update on new synthetic chiral compounds with antileishmanial activity

Parasitic diseases, including malaria, leishmaniasis, and trypanosomiasis, affect billions of people and are responsible for almost 500,000 deaths/year. In particular, leishmaniasis, a neglected tropical disease, is considered a global public health problem because current drugs have several drawbacks including to toxicity, high cost, and drug resistance, which result in a lack of effective and readily available therapies. Therefore, the synthesis of new, safe, and effective molecules still requires the attention of the scientific community. Moreover, it is well known that chirality plays a crucial role in the antiparasitic activity of molecules, driving the design of their synthesis. Therefore, in this review we report a recent update on new chiral compounds with promising antileishmanial activity, focusing on synthetic approaches. Where reported, in most cases the enantiopure compound has shown better potency against the protozoa than its enantiomer or corresponding racemic mixture.

Spatiotemporal analysis of cutaneous leishmaniasis in Palestine and foresight study by projections modelling until 2060 based on climate change prediction

Background

Cutaneous leishmaniasis (CL) is a vector-borne parasitic diseases of public health importance that is prevalent in the West Bank but not in the Gaza Strip. The disease caused by parasitic protozoans from the genus Leishmania and it is transmitted by infected phlebotomine sand flies. The aim of our study is to investigate the eco-epidemiological parameters and spatiotemporal projections of CL in Palestine over a 30-years period from 1990 through 2020 and to explore future projections until 2060.

Methodology/Principal findings

This long-term descriptive epidemiological study includes investigation of demographic characteristics of reported patients by the Palestinian Ministry of Health (PMoH). Moreover, we explored spatiotemporal distribution of CL including future projection based on climate change scenarios. The number of CL patients reported during this period was 5855 cases, and the average annual incidence rate (AAIR) was 18.5 cases/10⁵ population. The male to female ratio was 1.25:1. Patients-age ranged from 2 months to 89 years (mean = 22.5, std 18.67, and the median was 18 years). More than 65% of the cases came from three governates in the West Bank; Jenin 29% (1617 cases), Jericho 25% (1403), and Tubas 12% (658) with no cases reported in the Gaza Strip. Seasonal occurrence of CL starts to increase in December and peaked during March and April of the following year. Current distribution of CL indicate that Jericho, Tubas, Jenin and Nablus have the most suitable climatic settings for the sandfly vectors. Future projections until 2060 suggest an increasing incidence from northwest of Jenin down to the southwest of Ramallah, disappearance of the foci in Jericho and Tubas throughout the Jordan Vally, and possible emergence of new foci in Gaza Strip.

Conclusions/Significance

The future projection of CL in Palestine until 2060 show a tendency of increasing incidence in the north western parts of the West Bank, disappearance from Jericho and Tubas throughout the Jordan Vally, and emergence of new CL endemic foci in the Gaza Strip. These results should be considered to implement effective control and surveillance systems to counteract spatial expansion of CL vectors.

Climate Change Influences on the Potential Distribution of the Sand Fly Phlebotomus sergenti, Vector of Leishmania tropica in Morocco

BACKGROUND

Leishmaniases are a vector-borne disease, re-emerging in several regions of the world posing a burden on public health. As other vector-borne diseases, climate change is a crucial factor affecting the evolution of leishmaniasis. In Morocco, anthroponotic cutaneous leishmaniasis (ACL) is widespread geographically as many foci across the country, mainly in central Morocco. The objective of this study is to evaluate the potential impacts of climate change on the distribution of ACL due to Leishmania tropica, and its corresponding vector Phlebotomus sergenti in Morocco.

METHODS

Using Ecological Niche Modeling (ENM) tool, the estimated geographical range shift of L. tropica and P. sergenti by 2050 was projected under two Representative's Concentration's Pathways (RCPs) to be 2.6 and RCP 8.5 respectively. P. sergenti records were obtained from field collections of the laboratory team and previously published entomological observations, while, epidemiological data for L. tropica were obtained from Moroccan Ministry of Health reports.

RESULTS

Our models under present-day conditions indicated a probable expansion for L. tropica as well as for its vector in Morocco, P. sergenti. It showed a concentrated distribution in the west-central and northern area of Morocco. Future predictions anticipate expansion into areas not identified as suitable for P. sergenti under present conditions, particularly in northern and southeastern areas of Morocco. L. tropica is also expected to have high expansion in southern areas for the next 30 years in Morocco.

CONCLUSION

This indicates that L. tropica and P. sergenti will continue to find suitable climate conditions in the future. A higher abundance of P. sergenti may indeed result in a higher transmission risk of ACL. This information is essential in developing a control plan for ACL in Morocco. However, future investigations on L. tropica reservoirs are needed to confirm our predictions.

A conceptual model for understanding the zoonotic cutaneous leishmaniasis transmission risk in the Moroccan pre-Saharan area

Leishmanioses are of public health concern in Morocco, mainly the Zoonotic Cutaneous Leishmaniasis (ZCL) endemic in the Moroccan pre-Saharian area. Transmission of this disease depends on eco-epidemiological and socio-economic conditions. Therefore, a multivariable approach is required to delineate the risk and intensity of transmission. This will help outline main disease risk factors and understand interactions between all underlying factors acting on disease transmission at a local and regional scale. In this context, we propose a new conceptual model, the Biophysical-Drivers-Response-Zoonotic Cutaneous Leishmaniasis (BDRZCL), adapted to the Pre-Saharian area. The proposed model highlights how the physical and human drivers affect the environment and human health. The incidence of ZCL is linked to human activity and biophysical changes or by their interactions. The human response added to risk drivers are the main components that influence the biophysical part. This model improves our understanding of the cause-effect interactions and helps decision-makers and stakeholders react appropriately.

Epidemiological situation analysis of cutaneous leishmaniasis in Batna (northeast): An important focus in Algeria

Cutaneous leishmaniasis (CL) is a parasitic infection which poses a real public health problem in various countries, including Algeria. We aimed in this study to investigate the current epidemiological situation of CL in the wilaya of Batna (northeastern Algeria) during 2010-2020 and to discuss some control measures used to combat the disease in the most endemic foci. Data on CL cases and control measures were obtained from the "Direction de la Santé et de la Population (DSP) of Batna" and the "Etablissement Public de la Santé de Proximité (EPSP) of Barika". Data were analyzed and mapped using Microsoft Office Excel 2007, SPSS.21, and ArcGIS 10.3. A total of 9259 cases were notified, with a peak incidence of 1924 cases in 2010. The annual evolution of the disease showed decreasing and increasing trends during the study period. Cases were detected year-round, with a peak notification in November (1957 cases) and January (1663 cases). CL affects both genders and all age groups with predominance for males (58.6%) and infants less than 9 years old (54.4%). Most cases have occurred in western areas of the wilaya especially in the commune of Barika with 2979 cases (32.17%), followed by Abdelkader Azil (13.37%), Bitam (12.32%), Djezzar (8.67%), Ouled Ammar (7.07%), and Amdoukal (4.36%) communes. Spatiotemporal analysis showed that the highest frequencies of CL were exclusively reported in the western regions. There was no evidence of a possible relationship between Deltamethrin house spraying and leishmaniasis incidence. This study revealed that CL is highly endemic in the western areas of Batna, especially in Barika, with children less than 9 years old as the most age group at risk. The development of control measures and the selection of appropriate strategies are necessary to prevent, control, and eradicate the disease.

The potential impact of climate change on the seasonality of Phlebotomus neglectus, the vector of visceral leishmaniasis in the East Mediterranean region

Phlebotomus neglectus is one of the most important vectors of visceral leishmaniasis in Southeast Europe and Asia Minor. It was aimed to study the impact of climate change on the seasonality and the range of the species for 2014-2060. In the inland areas of Asia Minor, the Balkan Peninsula and the Carpathian Basin the elongation of the activity season will reach or exceed the two months in the middle of the 21st century compared to the end of the 20th century. The most affected regions are the middle elevations of the mountainous regions and the plains of the northern distribution areas. In some areas of the southern distribution border, the season is expected to shorten. In the Apennine Peninsula, mainly the mountainous areas could be impacted notably by climate change. The results indicate the potential spread of leishmaniasis in Southeast Europe due to the increasing environmental suitability of the region.

The impact of climate change on neglected tropical diseases: a systematic review

Neglected tropical diseases (NTDs) are a diverse group of diseases that continue to affect >1 billion people, with these diseases disproportionately impacting vulnerable populations and territories. Climate change is having an increasing impact on public health in tropical and subtropical areas and across the world and can affect disease distribution and transmission in potentially diverse ways. Improving our understanding of how climate change influences NTDs can help identify populations at risk to include in future public health interventions. Articles were identified by searching electronic databases for reports of climate change and NTDs between 1 January 2010 and 1 March 2020. Climate change may influence the emergence and re-emergence of multiple NTDs, particularly those that involve a vector or intermediate host for transmission. Although specific predictions are conflicting depending on the geographic area, the type of NTD and associated vectors and hosts, it is anticipated that multiple NTDs will have changes in their transmission period and geographic range and will likely encroach on regions and populations that have been previously unaffected. There is a need for improved surveillance and monitoring to identify areas of NTD incursion and emergence and include these in future public health interventions.

Cutaneous Leishmaniasis in Algeria; Highlight on the Focus of M'Sila

Algeria ranks second after Afghanistan for the incidence of cutaneous leishmaniasis (CL) worldwide. Here, we report a 34-years retrospective analysis of CL in Algeria and focused on the most affected region, the M’Sila province. All 66 cutaneous isolates corresponded to Leishmania (L.) major. Our study of the sandfly and rodent fauna further highlighted the high density of Phlebotomus papatasi and additional phlebotomine species of medical importance, not previously identified in M’Sila. Wild rodents belonging to nine species were trapped in M’Sila, and Psammomys obesus and Meriones shawi were found infected by L. major. In addition, Leishmania infantum was isolated from two visceral leishmaniasis cases, one dog and its proven vectors (P. perniciosus, P. longicuspis, and P. perfiliewi) inventoried during the survey. The high incidence of CL in the M’Sila province is likely a consequence of the increase in minimum temperatures recorded that constitutes suitable conditions for establishing a high endemicity and leads to an explosive rise in leishmaniases cases in this region. A thorough investigation of the underlying risk factors is urgently needed to detect new cases earlier. All these would improve the preparedness to fight the disease.

Eco-epidemiological aspects of Zoonotic cutaneous leishmaniasis in Ouarzazate Province, Morocco

Some epidemiological and ecological aspects of Zoonotic cutaneous leishmaniasis (ZCL) in Ouarzazate province, southern Morocco, were explored with the objective of analyzing ZCL distribution and associated ecological factors. Information on cutaneous leishmaniasis patients attending the local health centers of Ouarzazate during the period 2002-2009 was gathered and compiled. Urban, peri-urban, rural origin, precipitation, wind speed, temperature, water irrigation, dam volume, and altitude were studied. The findings show that the disease affected 5405 person during this period; the major part was found in the municipalities near both oases (desert oasis) and water resources, with a high concentration of cases in the peri-urban area. The highest percentage of cases was recorded mainly in September. Considerable associations were found between relative humidity and wind speed with ZCL occurrence. A large number of cases were recorded in areas with altitude ranging from 800 to 2000 m.a.s.l. and spatial precipitation from 15 to 150 mm. The statistical analysis showed a strong association between water storage volume and water irrigation with the annual ZCL occurrence recorded in the downstream area (Zagora province). The results will lead us to understand ZCL risk areas for effective control. Further work is needed mainly for gathering these variables in one single and simplest model.

Updates on Geographical Dispersion of Leishmania Parasites Causing Cutaneous Affections in Algeria

Leishmaniases are neglected tropical diseases of public health concern in Algeria. To update the geographical distribution of Leishmania spp. causing cutaneous affection, we examined a set of Giemsa-stained smears prepared from skin lesions of the patients suspected to have cutaneous leishmaniasis (CL) in various geographical areas in Algeria. The identification of Leishmania parasites was performed using microscopy, conventional PCR, and PCR-RFLP (PCR-Restriction Fragment Length Polymorphism) targeting ITS1-rDNA. Among 32 smears provided from 27 suspected patients with cutaneous lesions, no trace of parasites was observed in the smear of three patients using microscopy and molecular approaches. Furthermore, four patients presented at least two lesions. PCR-RFLP confirmed the presence of Leishmania in 29 smears prepared from 24 patients. Two biopsies, negative after microscopic examination, were found positive by PCR. Of these 29 PCR positive smears (24 patients), 20 were identified using RFLP-PCR as L. major, two as L. tropica, and two as L. infantum. We found L. major infected patients from Ain skhouna, Biskra, El M'hir, Ghardaïa, M'Sila, and Saida, in agreement with previously reported cases. Furthermore, we highlighted for the first time, the identification of L. major in the patients from Bourkika, Bou Kremissa, Bou Saada Clef, Hajout, Maghnia, Médéa, Menaceur, Messad, Mostaghanem, Nador, Oran, and Sidi Okba. A phylogenetic reconstruction performed with sequences collected from the PCR products confirmed these identifications. Our data provide additional information on the geographical extension of CL caused by L. tropica and L. infantum in Algeria.

Impact of Climatic Factors on the Seasonal Fluctuation of Leishmaniasis Vectors in Central Morocco (Meknes Prefecture)

The impact of climate factors on the epidemiology of diseases in general and leishmaniasis in particular continues to be a subject of research and analysis. Changes in climatic parameters contribute to the creation of ecological conditions favorable to the multiplication of the vectors of certain diseases. With this in mind, this study presents an entomological survey conducted in Meknes prefecture and the study of the link between the abundance of sandflies, an indicator of the risk of leishmaniasis in a given area, and the climatic factors. Monthly trapping of this fauna was carried out during a year from March 2016 until April 2017 using adhesive traps. Climatic data from the region were used to determine the effect of climate on the distribution of sandflies. A total of 941 leishmaniasis vector specimens were captured. The dominant species is Ph. sergenti (73.32), followed by Ph. longicuspis (8.25%), then Ph. perniciosus (7.94%) and Ph. papatasi (6.31%). The sex ratio study showed that males are more abundant than females for all species. The seasonal fluctuation is bimodal with two peaks, the first in July and the second in September. The results show a positive correlation between temperature and abundance of sandflies (r = 0.99) and a negative correlation with humidity and precipitation with a correlation coefficient of r = −0.87 and r = −0.72. Indeed, the medium-term climatological forecasts are essential tools to develop a warning system for leishmaniasis.

Efficiency of Two Capture Methods Providing Live Sand Flies and Assessment the Susceptibility Status of Phlebotomus papatasi (Diptera: Psychodidae) in the Foci of Cutaneous Leishmaniasis, Lorestan Province, Western Iran

Background:

The aims of this study were to evaluate the efficiency of two capture methods for providing live sandflies used for determining the susceptibility level of Phlebotomus papatasi, the main vector of zoonotic cutaneous leishmaniasis in Lorestan Province, west of Iran.

Methods:

The sand flies were collected from indoor and outdoor by hand-catch and baited traps during the peak of seasonal activity. The susceptibility level of sand flies was assessed using insecticide-impregnated papers against DDT 4%, bendiocarb 0.1%, permethrin 0.75%, deltamethrin 0.05%, and cyfluthrin 0.15%.

Results:

A total of 2486 live sandflies were caught from both indoor and outdoor places. Totally 849 sand flies were caught from outdoors with a sex ratio(SR) 0.1 versus 1637 sand flies collected from indoor using the hand-catch method with SR= 0.6. The dominant species of sand flies was Ph. papatasi in the study area. Mortality rates of outdoor-collected sand flies were exposed to DDT 4%, deltamethrin 0.05%, permethrin 0.75%, and bendiocarb 0.1%, and mortality rate ranged from 92.0–97.9% and for indoor-collected sand flies were 87.7–96.8%. Both outdoor and indoor collected sand flies were susceptible to cyfluthrin 0.15% that caused 100% mortality.

Conclusion:

Based on the findings, the most appropriate method for collecting the live female Ph. papatasi is the baited traps due to providing enough females is necessary for conducting the susceptibility tests. The finding indicated that Ph. papatasi was resistant to DDT, under ’verification required’ status to deltamethrin, permethrin, bendiocarb, and susceptible to cyfluthrin.

Sand Flies Control: A Review of the Knowledge of Health Professionals and the Local Community, Province of El Hajeb, Morocco

Sand flies are insect vectors of several diseases including leishmaniases. These vector-borne diseases represent a public health problem in several countries around the world, including Morocco. The objective of this study was to assess simultaneously the knowledge of health professionals and inhabitants on sand flies; a cross-sectional survey was conducted between April and June 2019 among 424 people, 34% of whom were health professionals and 66% of whom were inhabitants of the province of El Hajeb in central Morocco; 46.3% of doctors, 50.7% of nurses, 66.7% of midwives and 69.4% of inhabitants showed a low knowledge of sand flies. Most participants believed that sand flies breed in stagnant and polluted waters. Negative attitudes were found among 72.2% of the inhabitants. Factors associated with a high level of knowledge included continuing education among health professionals and information on vector-borne diseases among residents. The conceptual and cognitive gaps in the knowledge of sand flies reflect the lack of information and training on sand flies. The results of the sand fly knowledge review can be integrated into the national leishmaniases control program and the integrated vector management strategy to raise public awareness on the health risks of sand flies.

Emerging and Re-Emerging Leishmaniases in the Mediterranean Area: What Can Be Learned from a Retrospective Review Analysis of the Situation in Morocco during 1990 to 2010?

In Morocco, cutaneous and visceral leishmaniases represent a public health concern. In this opinion paper, we propose to highlight chosen elements that have governed the drastic increase in the incidence of leishmaniases recorded in Morocco during the period between 1990 to 2010 in order to guide the prediction of the expansion of diseases and epidemic events. We highlight that the dispersion of the zoonotic cutaneous leishmaniasis (ZCL) form, caused by the Leishmania major parasite, appears to be closely related to that of its arthropod vector density, which is sensitive to changes in climate. The dissemination of anthroponotic cutaneous leishmaniasis (ACL) was related to an increase in human travel and local tourism during the studied decades. These are linked to economic expansion and infrastructure development. Interestingly, the main ACL foci are spatially aligned with the highways, and their occurrence was synchronized with the building of transportation infrastructure. During the above-mentioned decades, the zoonotic visceral leishmaniasis (ZVL) caused by Leishmania infantum has expanded from its historical northern territories, dispersing outwards in all directions. This spread follows the emergence of hamlets and villages connecting with major cities.

Seasonal Distribution of Phlebotomus papatasi, Vector of Zoonotic Cutaneous Leishmaniasis

PURPOSE

The activity of Phlebotomus papatasi Scopoli, a vector of cutaneous leishmaniasis, is known to be seasonal, but the information describing these patterns is sparse in time and space. The purpose of his paper is to conduct a meta-analysis to depict the seasonality of P. papatasi at the global scale.

METHODS

The current paper uses data from a collection of 1200 scientific papers, where 300 are about the vector and 36 include monthly data (of 61 sites) of the P. papatasi from 15 countries published from 1994 to 2017.

RESULTS

The activity peaked mainly in dry periods in all explored sites. A map of seasonal distribution depicted a peak activity in August, followed by September. Geographically (geographic preference), August and September at the latitude 33° showed the highest abundance at a global scale. Concerning the latitude P. papatasi distribution, the high number is localized between 27° and 35°. However, the high number of this species according to the longitude is localized between - 4° and 58°, which shows a high interval of activity. Locally, for the habitat preference, the findings show a preference of this vector to indoor than to outdoor.

CONCLUSIONS

All these results can be helpful in identifying the period and sites of a future potential risk of leishmaniasis. This is the first attempt at the update of the vector activity both at global and local scale.

Modeling Spatial Distribution of Sergentomyia minuta (Diptera: Psychodidae) and Its Potential Implication in Leishmaniasis Transmission in Morocco

Background:

Leishmaniases are parasitic diseases caused by Leishmania species and transmitted by the bite of sand flies. The genus Lutzomyia and Phlebotomus of sand flies are known to be the responsible vector for transmitting almost all Leishmania species to humans. The detection of Leishmania DNA in species of the genus Sergentomyia, in different regions, suggests their likely role in Leishmania transmission.

Methods:

Our objective was to determine the potential geographical distribution of Sergentomyia minuta, the most dominant Sergentomyia species in Morocco, using ecological niche modeling.

Results:

The results showed the widespread geographical distribution of S. minuta in Morocco, specifically in northern and central Morocco where visceral and cutaneous leishmaniasis foci occur. There were six abiotic factors affecting the distribution of S. minuta whose annual precipitation, precipitation seasonality and precipitation of driest month as the most important ecological variables of the model.

Conclusion:

A positive statistical correlation between human leishmaniasis cases and S. minuta abundance was noted suggesting the potential involvement of S. minuta in local Leishmania transmission cycles.

Risk Factors Associated with Leishmaniasis in the Most Affected Provinces by Leishmania infantum in Morocco

Background

Human leishmaniasis, both visceral and cutaneous, has been reported in Morocco for centuries and constitutes a serious public health problem. However, the evolution of this pathology depends on several factors such as ecological, socioeconomic, and climatic conditions. The risk study of the affected foci is of great value for the control and surveillance of this endemic disease, especially in the provinces where Leishmania infantum predominates.

Methods

This study concerned nine provinces located in the extreme and central north of Morocco (Taounate, Taza, Chefchaouen, Al Hoceima, Larache, Tétouane, Tanger-Assilah, M'diq-Fnideq, and Fahs-Anjra Provinces). In this work, leishmaniasis cases (VL and CL) were subjected to an epidemiological study which was performed using a linear regression model to identify the impact as well as the interaction between all predictor variables on the distribution of leishmaniasis in this region.

Results

During the period 1997–2018, a total of 6 128 cases of VL and CL were recorded in the study area. Our results showed that among demographic factors studied, urbanization showed significance for both cutaneous and visceral forms (P < 0.05). Regarding the environmental factors, the humidity and the altitude were significant for both CL and VL (P < 0.05), while the temperature and the normalized difference vegetation index (NDVI) showed a significance only for VL. Moreover, trends in season of occurrence revealed that wet season (October to April) had a higher incidence of leishmaniasis compared to the dry season (May to September) specifically for CL. As for socioeconomic factors, poverty was the only factor that influences the spread of VL. Finally, the distance from endemic foci showed significance for both VL and LC (P < 0.05).

Conclusion

Our study revealed that the risk factor associated with cutaneous and visceral leishmaniasis in northern Morocco could help in the establishment of a prediction program.

Impact of meteorological and geographical factors on the distribution of leishmaniasis's vector in mainland China

BACKGROUND

Phlebotomine sandfly (Diptera: Psychodidae) is best known for its role as the vector of the leishmaniasis. Leishmaniasis is a global disease, currently known to be affecting 88 countries and 12 million people worldwide.

RESULTS

This study explored the impacts of climate factors and landscape on the local abundance of Phlebotomine sandfly in mainland China. A presence-only modelling method was used to evaluate this species' habitat preferences from environmental factors. Jackknife analysis revealed that several biologically meteorological variables, including the maximum temperature of the warmest quarter, the precipitation in the driest month, the daily average temperature and daily precipitation, would significantly affect the existence of this species. Moreover, the existence of Phlebotomine sandfly was significantly associated with grassland and forest.

CONCLUSION

The results will improve scientific understanding of the risks of the spread of leishmaniasis over current infected areas and can be used to design more detailed surveillance programmes and more evidence-based control planning for Phlebotomine sandfly and leishmaniasis. © 2019 Society of Chemical Industry.

Phlebotomine sand flies and Leishmania species in a focus of cutaneous leishmaniasis in Algeria

Cutaneous leishmaniasis is a disease caused by various Leishmania spp., which are transmitted by phlebotomine sand flies. Algeria is one of the most affected countries, with thousands of cutaneous leishmaniasis cases registered every year. From March to November of 2016 and 2017, sand flies were collected in 12 municipalities in Setif province, North-Eastern Algeria. Sand flies were identified and females were tested by PCR for detecting Leishmania DNA. Additionally, cutaneous leishmaniasis cases notified during the study period were analysed. Out of 1804 sand flies collected, 1737 were identified as belonging to seven species, with Phlebotomus perniciosus (76.2%), Ph. papatasi (16.7%) and Ph. sergenti (5.0%) being the most common species, representing together 97.9% of the collected specimens. The remaining specimens were identified as Sergentomyia minuta, Se. fallax, Ph. longicuspis and Ph. perfiliewi. The number of sand flies collected monthly was positively correlated with temperature. Out of 804 females tested, nine Ph. perniciosus (1.1%) scored positive for Leishmania infantum (n = 5), L. major (n = 3) and L. tropica (n = 1), respectively. During the study period, 34 cutaneous leishmaniasis cases were notified in Setif, of which 58.8% were patients residing in two urban and peri-urban municipalities and 41.2% in rural areas. The finding of Ph. perniciosus as the most abundant species in Setif suggests that this sand fly may be adapted to different biotopes in the North-East region of Algeria. The detection of different Leishmania spp. in Ph. perniciosus suggests a complex epidemiological picture of cutaneous leishmaniasis in Setif, with the involvement of different etiological agents and possibly with different reservoir hosts and vectors.

Leishmaniasis is a group of neglected diseases, with more than 350 million people at risk and 2 million new cases every year. Leishmania parasites are transmitted by phlebotomine sand flies. Algeria is one of most affected countries, with thousands of cutaneous leishmaniasis cases registered every year. However, in spite of the scientific knowledge gained over the last decades, the understanding of the biology and the ecology of sand flies in some areas of Algeria is still fragmentary. The present study was conducted from 2016 to 2017 to assess the sand fly population in Setif and also the Leishmania spp. circulating in this province. Our data suggest a complex epidemiological picture of cutaneous leishmaniasis in Setif, with the involvement of different etiological agents and possibly with different reservoir hosts and vectors.

The effects of climate change on human health in Africa, a dermatologic perspective: a report from the International Society of Dermatology Climate Change Committee

Throughout much of the African continent, healthcare systems are already strained in their efforts to meet the needs of a growing population using limited resources. Climate change threatens to undermine many of the public health gains that have been made in this region in the last several decades via multiple mechanisms, including malnutrition secondary to drought-induced food insecurity, mass human displacement from newly uninhabitable areas, exacerbation of environmentally sensitive chronic diseases, and enhanced viability of pathogenic microbes and their vectors. We reviewed the literature describing the various direct and indirect effects of climate change on diseases with cutaneous manifestations in Africa. We included non-communicable diseases such as malignancies (non-melanoma skin cancers), inflammatory dermatoses (i.e. photosensitive dermatoses, atopic dermatitis), and trauma (skin injury), as well as communicable diseases and neglected tropical diseases. Physicians should be aware of the ways in which climate change threatens human health in low- and middle-income countries in general, and particularly in countries throughout Africa, the world's lowest-income and second most populous continent.

Modelling and evaluating the risk of zoonotic cutaneous leishmaniasis in selected areas of Kerman Province, south of Iran

Cutaneous leishmaniasis (CL) remains a public health problem in the world, particularly in tropical and sub-tropical countries. This study aimed to determine the hotspots of CL in Kerman Province of Iran and model their potential for the establishment of new disease foci. All documents related to studies conducted in Kerman Province on CL published between 1978 and 2017 were retrieved and categorized. Spatial distributions of the vector, reservoir and human infection of CL were mapped. MaxEnt ecological model was used to predict the environmental suitability of the vector and reservoir(s) of zoonotic cutaneous leishmaniasis (ZCL). The most hazardous sites with the potential for the establishment of new disease foci were determined for field operations. Statistics of new cases of CL was obtained from the Center for Disease Control (CDC) of the ministry of health for the period 2011-2016. A total of 6,056 cases of CL were recorded, while we found a decreasing pattern in the incidence of CL from 46.48 per 100,000 inhabitants to 22.97. The best ecological niches for Phlebotomus papatasi are located in the central, western, northwest and southwest regions of the province. Also, environmental suitability for the reservoirs was highest in the central, southern and southwestern regions. The model predicted the gerbils can be present in some foci of anthroponotic cutaneous leishmaniasis (ACL). However, this result should be confirmed through a precise field study, and if validated, plans should be made to prevent the emergence of new foci of ZCL in the risk areas.

Epidemiology and spatiotemporal analysis of visceral leishmaniasis in Palestine from 1990 to 2017

OBJECTIVES

Visceral leishmaniasis (VL) is a deadly disease endemic in all countries around the Mediterranean Sea. In Palestine, VL is transmitted to humans from infected dogs by a sandfly bite. The aim of this study was to investigate the epidemiology and spatiotemporal pattern of VL in Palestine within a period of 27 years (1990-2017).

METHODS

A long-term descriptive epidemiological study on human VL was conducted based on patient's profiles to calculated disease prevalence, geographical, spatiotemporal and seasonal distribution, distribution by age and gender, diagnosis, treatment, and treatment outcome.

RESULTS

A total of 343 patients were reported, the average annual incidence rate was 0.73 case/100000 population. Most cases came from the western parts of the West Bank. The number of reported males was 162 (51%), and patient's age ranged from 4 months to 16 years (average 2.5 years), of which 93.3% were ≤5 years old. The annual incidence rate increased between 1993-1999, peaked in 1995, and dropped as from 2002. The future projections of VL indicate that the endemic foci in most governorates are projected to disappear in the future and only the very northwest of the West Bank will be at risk of VL.

CONCLUSIONS

Visceral leishmaniasis continues to be endemic in the West Bank but not the Gaza Strip. Pentavalent antimonial sodium stibogluconate continues to be the first line treatment and physicians are recommended to consider liposomal Amphotericin B (AmBisome) for refractory patients only. Geographical, spatiotemporal and seasonal trends of VL were identified.

Impact of meteorological and geographical factors on the distribution of Phlebotomus chinensis in northwestern mainland China

Phlebotomine sandflies (Diptera: Phlebotomidae) are vectors of the zoonotic disease leishmaniasis. To better understand the distribution of phlebotomine sandflies in order to facilitate control of leishmaniasis transmission, the present study explored the impacts of climate and landscape on local abundances of Phlebotomus chinensis in northwestern mainland China. Identification records were used to create a geodatabase for the locations at which P. chinensis had been collected in the region, and a regional-scale map was developed to show the distribution of P. chinensis. Location data and data on environmental factors during the years in which the samples were collected were incorporated, and a presence-only modelling method was used to evaluate the species' habitat preferences and to predict its potential distribution in northwestern mainland China. Jackknife analysis revealed that several meteorological variables, including maximum temperature in the warmest quarter, precipitation in the driest month, daily average temperature and daily precipitation, significantly affected the presence of this species. Moreover, the presence of P. chinensis was significantly associated with grassland and shrubland. Probability distributions using maximum entropy were used to map the distribution ranges of P. chinensis based on suitable habitats in northwestern mainland China. The models generated can be used to develop detailed strategies for the prevention and control of leishmaniasis.

Management of Leishmaniases in the Era of Climate Change in Morocco

The proliferation of vector-borne diseases are predicted to increase in a changing climate and Leishmaniases, as a vector-borne diseases, are re-emerging diseases in several regions of the world. In Morocco, during the last decade, a sharp increase in cutaneous leishmaniases cases has been reported. Nevertheless, in Morocco, leishmaniases are a major public health problem, and little interest was given to climate change impacts on the distribution and spread of these diseases. As insect-borne diseases, the incidence and distribution of leishmaniases are influenced by environmental changes, but also by several socio-economic and cultural factors. From a biological point of view, environmental variables have effects on the survival of insect vectors and mammalian reservoirs, which, in turn, affects transmission. Here, we highlight the effects of climate change in Morocco and discuss its consequences on the epidemiology of leishmaniases to identify challenges and define targeted recommendations to fight this disease.

Impact of climate variability on the transmission risk of malaria in northern Côte d'Ivoire

Since the 1970s, the northern part of Côte d'Ivoire has experienced considerable fluctuation in its meteorology including a general decrease of rainfall and increase of temperature from 1970 to 2000, a slight increase of rainfall since 2000, a severe drought in 2004-2005 and flooding in 2006-2007. Such changing climate patterns might affect the transmission of malaria. The purpose of this study was to analyze climate and environmental parameters associated with malaria transmission in Korhogo, a city in northern Côte d'Ivoire. All data were collected over a 10-year period (2004-2013). Rainfall, temperature and Normalized Difference Vegetation Index (NDVI) were the climate and environmental variables considered. Association between these variables and clinical malaria data was determined, using negative binomial regression models. From 2004 to 2013, there was an increase in the annual average precipitation (1100.3-1376.5 mm) and the average temperature (27.2°C-27.5°C). The NDVI decreased from 0.42 to 0.40. We observed a strong seasonality in these climatic variables, which resembled the seasonality in clinical malaria. An incremental increase of 10 mm of monthly precipitation was, on average, associated with a 1% (95% Confidence interval (CI): 0.7 to 1.2%) and a 1.2% (95% CI: 0.9 to 1.5%) increase in the number of clinical malaria episodes one and two months later respectively. A 1°C increase in average monthly temperature was, on average, associated with a decline of a 3.5% (95% CI: 0.1 to 6.7%) in clinical malaria episodes. A 0.1 unit increase in monthly NDVI was associated with a 7.3% (95% CI: 0.8 to 14.1%) increase in the monthly malaria count. There was a similar increase for the preceding-month lag (6.7% (95% CI: 2.3% to 11.2%)). The study results can be used to establish a malaria early warning system in Korhogo to prepare for outbreaks of malaria, which would increase community resilience no matter the magnitude and pattern of climate change.

Forecasting zoonotic cutaneous leishmaniasis using meteorological factors in eastern Fars province, Iran: a SARIMA analysis

OBJECTIVES

To predict the occurrence of zoonotic cutaneous leishmaniasis (ZCL) and evaluate the effect of climatic variables on disease incidence in the east of Fars province, Iran using the Seasonal Autoregressive Integrated Moving Average (SARIMA) model.

METHODS

The Box-Jenkins approach was applied to fit the SARIMA model for ZCL incidence from 2004 to 2015. Then the model was used to predict the number of ZCL cases for the year 2016. Finally, we assessed the relation of meteorological variables (rainfall, rainy days, temperature, hours of sunshine and relative humidity) with ZCL incidence.

RESULTS

SARIMA(2,0,0) (2,1,0)12 was the preferred model for predicting ZCL incidence in the east of Fars province (validation Root Mean Square Error, RMSE = 0.27). It showed that ZCL incidence in a given month can be estimated by the number of cases occurring 1 and 2 months, as well as 12 and 24 months earlier. The predictive power of SARIMA models was improved by the inclusion of rainfall at a lag of 2 months (β = -0.02), rainy days at a lag of 2 months (β = -0.09) and relative humidity at a lag of 8 months (β = 0.13) as external regressors (P-values < 0.05). The latter was the best climatic variable for predicting ZCL cases (validation RMSE = 0.26).

CONCLUSIONS

Time series models can be useful tools to predict the trend of ZCL in Fars province, Iran; thus, they can be used in the planning of public health programmes. Introducing meteorological variables into the models may improve their precision.

Risk factors and prediction analysis of cutaneous leishmaniasis due to Leishmania tropica in Southwestern Morocco

Cutaneous leishmaniasis is currently a serious public health problem in northern Africa, especially in Morocco. The causative parasite is transmitted to a human host through the bite of infected female sandflies of the genus Phlebotomus. The objective of the present study is to characterize the causative organisms and to predict the risk of cutaneous leishmaniasis (CL) cases in six provinces in southwestern Morocco, based on the spatial distribution of cases in relation to environmental factors and other risk factors such as socio-economic status and demographics. A molecular study was carried out using ITS1 PCR-RFLP method of the ribosomal DNA of Leishmania. An epidemiological study on CL cases was reported between 2000 and 2016 in this current investigation in six provinces in southwestern Morocco. Statistical analysis was performed using a linear regression model to identify the impact as well as the interaction between all predictor variables on the distribution of CL in the studied provinces. The forecast Holt-Winters (HW) method was used to describe the trend and seasonality of CL cases. The ITS1-PCR- RFLP analysis revealed the presence of Leishmania tropica in all studied provinces. The spatial distribution of CL cases documented in all studied provinces during the sixteen years showed a heterogeneous pattern and fluctuation trend with an average prevalence of 9.92 per 100,000 inhabitants. In addition, the forecast HW model predicts continued variability of trend and seasonality of CL cases in the upcoming years. This study confirmed the importance of socioeconomic factors, in particular poverty and the vulnerability rate, on distribution and emergence of CL. This study revealed a relationship between increasing risk of CL occurrence due to Leishmania tropica, as well as the distribution and emergence thereof, and socioeconomic factors in the investigated area.

Spatial modeling of cutaneous leishmaniasis in Iranian army units during 2014-2017 using a hierarchical Bayesian method and the spatial scan statistic

OBJECTIVES

This study aimed to map the incidence of cutaneous leishmaniasis (CL) in Iranian army units (IAUs) and to identify possible spatial clusters.

METHODS

This ecological study investigated incident cases of CL between 2014 and 2017. CL data were extracted from the CL registry maintained by the deputy of health of AJA University of Medical Sciences. The standardized incidence ratio (SIR) of CL was computed with a Besag, York, and Mollié model. The purely spatial scan statistic was employed to detect the most likely highand low-rate clusters and to obtain the observed-to-expected (O/E) ratio for each detected cluster. The statistical significance of the clusters was assessed using the log likelihood ratio (LLR) test and Monte Carlo hypothesis testing.

RESULTS

A total of 1,144 new CL cases occurred in IAUs from 2014 to 2017, with an incidence rate of 260 per 100,000. Isfahan and Khuzestan Provinces were found to have more CL cases than expected in all studied years (SIR>1), while Kermanshah, Kerman, and Fars Provinces were observed to have been high-risk areas in only some years of the study period. The most significant CL cluster was in Kermanshah Province (O/E, 67.88; LLR, 1,200.62; p<0.001), followed by clusters in Isfahan Province (O/E, 6.02; LLR, 513.24; p<0.001) and Khuzestan Province (O/E, 2.35; LLR, 73.71; p<0.001), while low-rate clusters were located in the northeast areas, including Razavi Khorasan, North Khorasan, Semnan, and Golestan Provinces (O/E, 0.03; LLR, 95.11; p<0.001).

CONCLUSIONS

This study identified high-risk areas for CL. These findings have public health implications and should be considered when planning control interventions among IAUs.

Molecular detection of Leishmania infantum and Leishmania tropica in rodent species from endemic cutaneous leishmaniasis areas in Morocco

Background

Leishmaniasis remains a major public health problem in African nations, including Morocco, where little is known about the vertebrate reservoirs involved in the causal parasites’ transmission cycles. The present study investigates the role of rodent species as potential reservoirs of Leishmania spp. in central Morocco, where both L. tropica and L. infantum have been reported.

Methods

Rodents were caught from 22 sites in central Morocco, by using Sherman metal traps, and identified morphologically. For each specimen, genomic DNA was extracted from different tissues using the Speed Tools DNA extraction Kit. Then, samples were PCR-analyzed, targeting the SSU rRNA gene to detect Leishmania spp. DNA, followed by amplification of the internal transcribed spacer 1 (ITS1) and its sequencing to identify the species.

Results

A total of 197 rodents belonging to ten species were captured and identified: Rattus rattus (40.61%), Mus musculus (25.38%), Apodemus sylvaticus (8.63%), Mus spretus (7.11%), Meriones shawi (5.58%), Rattus norvegicus (4.57%), Meriones libycus (3.05%), Mastomys erythroleucus (2.03%), Gerbillus campestris (2.03%) and Lemniscomys barbarus (1.01%). Molecular analysis revealed the presence of Leishmania species in 18 specimens: six R. rattus (out of 80 captured; 7.5%), 11 M. musculus (out of 50 captured; 22%), and one R. norvegicus (out of 9 captured; 11.11%).

Conclusions

To the best of our knowledge, L. infantum and L. tropica were identified in rodent species for the first time in Morocco. These findings suggest that rodent species may be involved in L. infantum and L. tropica transmission cycles in this country but that further studies are needed to confirm their role as reservoirs of Leishmania species in Morocco.

Electronic supplementary material

The online version of this article (10.1186/s13071-017-2398-8) contains supplementary material, which is available to authorized users.

Spatiotemporal and molecular epidemiology of cutaneous leishmaniasis in Libya

Background

Cutaneous leishmaniasis (CL) is a major public health problem in Libya. In this paper, we describe the eco-epidemiological parameters of CL during the armed conflict period from January 2011 till December 2012. Current spatiotemporal distributions of CL cases were explored and projected to the future using a correlative modelling approach. In addition the present results were compared with our previous data obtained for the time period 1995–2008.

Methodology/Principal findings

We investigated 312 CL patients who presented to the Dermatology Department at the Tripoli Central Hospital and came from 81 endemic areas distributed in 10 districts. The patients presented with typical localized lesions which appeared commonly on the face, arms and legs. Molecular identification of parasites by a PCR-RFLP approach targeting the ITS1 region of the rDNA was successful for 81 patients with two causative species identified: L. major and L. tropica comprised 59 (72.8%) and 22 (27.2%) cases, respectively. Around 77.3% of L. tropica CL and 57.7% of L. major CL caused single lesions. Five CL patients among our data set were seropositive for HIV. L. tropica was found mainly in three districts, Murqub (27.3%), Jabal al Gharbi (27.3%) and Misrata (13.7%) while L. major was found in two districts, in Jabal al Gharbi (61%) and Jafara (20.3%). Seasonal occurrence of CL cases showed that most cases (74.2%) admitted to the hospital between November and March, L. major cases from November till January (69.4%), and L. tropica cases mainly in January and February (41%). Two risk factors were identified for the two species; the presence of previously infected household members, and the presence of rodents and sandflies in patient’s neighborhoods. Spatiotemporal projections using correlative distribution models based on current case data and climatic conditions showed that coastal regions have a higher level of risk due to more favourable conditions for the transmitting vectors.

Conclusion

Future projection of CL until 2060 showed a trend of increasing incidence of CL in the north-western part of Libya, a spread along the coastal region and a possible emergence of new endemics in the north-eastern districts of Libya. These results should be considered for control programs to prevent the emergence of new endemic areas taking also into consideration changes in socio-economical factors such as migration, conflicts, urbanization, land use and access to health care.

Cutaneous leishmaniasis (CL) is a skin infection caused by a single-celled parasite that is transmitted by the bite of a phlebotomine sandfly. CL is the most common form of leishmaniasis characterized by localized lesions in the skin and mucous membranes. The disease is prevalent in all countries around the Mediterranean Basin. In this paper, we describe spatiotemporal and eco-epidemiological parameters of CL in Libya. Moreover, we explored current spatiotemporal distributions of CL cases and explored the future projection of the disease. Our study indicates the presence of higher risk of CL in the coastal regions of Libya. Future projection until 2060 showed a trend of increasing incidence of CL in the north-western part of Libya, a spread along the coastal region and a possible emergence of new endemics in the north-eastern districts of Libya. These scenarios should be considered by health authorities in order to develop appropriate intervention strategies and plan effective control programs.

Phlebotomine sand fly-borne pathogens in the Mediterranean Basin: Human leishmaniasis and phlebovirus infections

Pathogens transmitted to humans by phlebotomine sand flies are neglected, as they cause infectious diseases that are not on the priority list of national and international public health systems. However, the infections caused by protozoa of the Leishmania genus and viruses belonging to the Phlebovirus genus (family Phenuiviridae)—the most significant group of viruses transmitted by sand flies—have a relevant role for human pathology. These infections are emerging in the Mediterranean region and will likely spread in forthcoming decades, posing a complex threat to human health. Four species and 2 hybrid strains of Leishmania are pathogenic for humans in the Mediterranean Basin, with an estimated annual incidence of 239,500–393,600 cases of cutaneous leishmaniasis and 1,200–2,000 cases of visceral leishmaniasis. Among the phleboviruses, Toscana virus can cause neuroinvasive infections, while other phleboviruses are responsible for a typical “3-day fever”; the actual incidence of Phlebovirus infections in the Mediterranean area is unknown, although at least 250 million people are exposed. Here, we reviewed the current literature on epidemiology of sand fly–borne infections in the Mediterranean Basin, with a focus on humans. Our analysis indicates the need for increased public health activities directed to determine the disease burden of these infections as well as to improve their surveillance. Among the emerging challenges concerning sand fly–borne pathogens, the relationships between sand fly–borne protozoa and viruses should be considered in future studies, including epidemiological links between Leishmania and phleboviruses as well as the conditional capacity for these pathogens to be involved in interactions that may evolve towards increased virulence.

Circulating species of Leishmania at microclimate area of Boulemane Province, Morocco: impact of environmental and human factors

BACKGROUND

Cutaneous leishmaniasis (CL) is widely distributed in Morocco where its geographical range and incidence are related to environmental factors. This study aimed to examine the impact of several factors on the distribution of CL in Boulemane Province, which is characterized by several microclimates, and to identify the Leishmania species circulating in these areas.

METHODS

Ordinary least squares regression (OLSR) analysis was performed to study the impact of poverty, vulnerability, population density, urbanization and bioclimatic factors on the distribution of CL in this province. Molecular characterization of parasites was performed using a previously described PCR-RFLP method targeting the ITS1 of ribosomal DNA of Leishmania.

RESULTS

A total of 1009 cases were declared in Boulemane Province between the years 2000 and 2015 with incidences fluctuating over the years (P = 0.007). Analyzing geographical maps of the study region identified four unique microclimate areas; sub-humid, semi-arid, arid and Saharan. The geographical distribution and molecular identification of species shows that the Saharan microclimate, characterized by the presence of Leishmania major was the most affected (47.78%) followed by semi-arid area where Leishmania tropica was identified in three districts. Among several environmental factors included in the study, poverty had the greatest influence on the spatial extension of the disease in this province.

CONCLUSIONS

The incidence of CL in Boulemane Province varies between microclimate areas, and environmental factors partly explain this variation. However, the existence of CL in the most affected districts is mainly related to poverty, population movement and human behavior. To our knowledge, this the first study utilizing molecular techniques to confirm L. tropica and L. major as the causative agents of CL in Boulemane Province. Our findings indicate that the spatial and temporal distribution of CL in Boulemane Province is strongly related to poverty and population movement.

Demographic and spatio-temporal distribution of cutaneous leishmaniasis in the Souf oasis (Eastern South of Algeria): Results of 13 years

Cutaneous leishmaniasis is one of many dangerous parasitic diseases. It remains a serious public health problem not only in Souf oasis, but also in Algeria and all developing countries. The results of our thirteen-year study shows a recording of 4813 confirmed cases of cutaneous leishmaniasis and the details shows that this disease affects all municipalities and all age groups, from infants to elderly, but the most affected ones are teenagers aging (10-19) years with 1512 cases (31.41%) and infants less than 9 years old with 1237 cases (25.70%). In addition, males are more prone to this disease than females (65% and 35% respectively). Among the 18 municipalities in the Souf, the most affected were El-Oued with 1171 cases (24.33%) followed by Guemar with 997 cases (20.71%). Furthermore, more than 40.03% of all cases (1927 cases), were record just in one year in 2010. A parallel, this study shows that the original factors of the studied area, such as climatological, agricultural and environmental factors, was the reason do not apparition this epidemic for a long time, but the changes in these conditions, resulting from various human activities create new environmental conditions, which help with the emergence and spread of leishmaniasis disease. The effective fight against this disease should be based on the elimination of the vectors and reservoirs populations, by the overall improvement of sanitary conditions and hygiene, extensive research in epidemiology of leishmaniasis could also reduce the incidence of cutaneous leishmaniasis.

Joint spatial time-series epidemiological analysis of malaria and cutaneous leishmaniasis infection

Malaria and leishmaniasis are among the two most important health problems of many developing countries especially in the Middle East and North Africa. It is common for vector-borne infectious diseases to have similar hotspots which may be attributed to the overlapping ecological distribution of the vector. Hotspot analyses were conducted to simultaneously detect the location of local hotspots and test their statistical significance. Spatial scan statistics were used to detect and test hotspots of malaria and cutaneous leishmaniasis (CL) in Afghanistan in 2009. A multivariate negative binomial model was used to simultaneously assess the effects of environmental variables on malaria and CL. In addition to the dependency between malaria and CL disease counts, spatial and temporal information were also incorporated in the model. Results indicated that malaria and CL incidence peaked at the same periods. Two hotspots were detected for malaria and three for CL. The findings in the current study show an association between the incidence of malaria and CL in the studied areas of Afghanistan. The incidence of CL disease in a given month is linked with the incidence of malaria in the previous month. Co-existence of malaria and CL within the same geographical area was supported by this study, highlighting the presence and effects of environmental variables such as temperature and precipitation. People living in areas with malaria are at increased risk for leishmaniasis infection. Local healthcare authorities should consider the co-infection problem by recommending systematic malaria screening for all CL patients.

Spatial patterns and secular trends in human leishmaniasis incidence in Morocco between 2003 and 2013

BACKGROUND

Few studies on spatial patterns or secular trends in human leishmanias have been conducted in Morocco. This study aimed to examine spatial patterns and trends associated with the human leishmaniasis incidence rate (HLIR) at the province/prefecture level between 2003 and 2013 in Morocco.

METHODS

Only the available published country data on the HLIR between 2003 and 2013, from the open access files of the Ministry of Health, were used. Secular trends were examined using Kendall's rank correlation. An exploratory spatial data analysis was also conducted to examine the spatial autocorrelation (Global Moran's I and local indicator of spatial association [LISA]), and spatial diffusion at the province/prefecture level. The influence of various covariates (poverty rate, vulnerability rate, population density, and urbanization) on the HLIR was tested via spatial regression (ordinary least squares regression).

RESULTS

At the country level, no secular variation was observed. Poisson annual incidence rate estimates were 13 per 100 000 population (95 % CI = 12.9-13.1) for cutaneous leishmaniasis (CL) and 0.4 per 100 000 population (95 % CI = 0.4-0.5) for visceral leishmaniasis (VL). The available data on HLIR were based on combined CL and VL cases, however, as the CL cases totally outnumbered the VL ones, HLIR may be considered as CL incidence rate. At the provincial level, a secular increase in the incidence rate was observed in Al Hoceima (P = 0.008), Taounate (P = 0.04), Larache (P = 0.002), Tétouan (P = 0.0003), Khenifra (P = 0.008), Meknes (P = 0.03), and El Kelaa (P = 0.0007), whereas a secular decrease was observed only in the Chichaoua province (P = 0.006). Even though increased or decreased rate was evident in these provinces, none of them showed clustering of leishmaniasis incidence. Significant spatial clusters of high leishmaniasis incidence were located in the northeastern part of Morocco, while spatial clusters of low leishmaniasis incidence were seen in some northwestern and southern parts of Morocco; there was spatial randomness in the remaining parts of the country. Significant clustering was seen from 2005 to 2013, during which time the Errachidia province was a permanent 'hot spot'. Global Moran's I increased from 0.2844 (P = 0.006) in 2005 to 0.5886 (P = 0.001) in 2011, and decreased to 0.2491 (P = 0.004) in 2013. It was found that only poverty had an effect on the HLIR (P = 0.0003), contributing only 23 % to this (Adjusted R-squared = 0.226).

CONCLUSION

Localities showing either secular increase in human leishmaniasis or significant clustering have been identified, which may guide decision-making as to where to appropriately allocate funding and implement control measures. Researchers are also urged to undertake further studies focusing on these localities.

Coarse-resolution Ecology of Etiological Agent, Vector, and Reservoirs of Zoonotic Cutaneous Leishmaniasis in Libya

Cutaneous leishmaniasis ranks among the tropical diseases least known and most neglected in Libya. World Health Organization reports recognized associations of Phlebotomus papatasi, Psammomys obesus, and Meriones spp., with transmission of zoonotic cutaneous leishmaniasis (ZCL; caused by Leishmania major) across Libya. Here, we map risk of ZCL infection based on occurrence records of L. major, P. papatasi, and four potential animal reservoirs (Meriones libycus, Meriones shawi, Psammomys obesus, and Gerbillus gerbillus). Ecological niche models identified limited risk areas for ZCL across the northern coast of the country; most species associated with ZCL transmission were confined to this same region, but some had ranges extending to central Libya. All ENM predictions were significant based on partial ROC tests. As a further evaluation of L. major ENM predictions, we compared predictions with 98 additional independent records provided by the Libyan National Centre for Disease Control (NCDC); all of these records fell inside the belt predicted as suitable for ZCL. We tested ecological niche similarity among vector, parasite, and reservoir species and could not reject any null hypotheses of niche similarity. Finally, we tested among possible combinations of vector and reservoir that could predict all recent human ZCL cases reported by NCDC; only three combinations could anticipate the distribution of human cases across the country.