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

Clinical and immunological spectra of human cutaneous leishmaniasis in North Africa and French Guiana

Cutaneous leishmaniasis (CL) caused by infection with the parasite Leishmania exhibits a large spectrum of clinical manifestations ranging from single healing to severe chronic lesions with the manifestation of resistance or not to treatment. Depending on the specie and multiple environmental parameters, the evolution of lesions is determined by a complex interaction between parasite factors and the early immune responses triggered, including innate and adaptive mechanisms. Moreover, lesion resolution requires parasite control as well as modulation of the pathologic local inflammation responses and the initiation of wound healing responses. Here, we have summarized recent advances in understanding the in situ immune response to cutaneous leishmaniasis: i) in North Africa caused by Leishmania (L.) major, L. tropica, and L. infantum, which caused in most cases localized autoresolutives forms, and ii) in French Guiana resulting from L. guyanensis and L. braziliensis, two of the most prevalent strains that may induce potentially mucosal forms of the disease. This review will allow a better understanding of local immune parameters, including cellular and cytokines release in the lesion, that controls infection and/or protect against the pathogenesis in new world compared to old world CL.

Cutaneous leishmaniasis situation analysis in the Islamic Republic of Iran in preparation for an elimination plan

Iran has invariably been under the growing public health threat of cutaneous leishmaniasis (CL), a significant barrier to local development that hinders the prevention and control efforts toward eliminating the disease. So far, no comprehensive and in-depth epidemiological analysis of the CL situation has been carried out nationwide. This study aimed to employ advanced statistical models to analyze the data collected through the Center for Diseases Control and Prevention of Communicable Diseases during 1989-2020. However, we emphasized the current trends, 2013-2020, to study temporal and spatial CL patterns. In the country, the epidemiology of CL is incredibly intricate due to various factors. This fact indicates that the basic infrastructure, the preceding supports, and the implementation plan related to preventive and therapeutic measures need crucial support. The leishmaniasis situation analysis is consistent with desperate requirements for efficient information on the control program in the area. This review provides evidence of temporally regressive and spatially expanding incidence of CL with characteristic geographical patterns and disease hotspots, signifying an urgent need for comprehensive control strategies. This information could be a suitable model and practical experience in the Eastern Mediterranean Region, where over 80% of CL is reported.

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.

Environmental, Climatic, and Parasite Molecular Factors Impacting the Incidence of Cutaneous Leishmaniasis Due to Leishmania tropica in Three Moroccan Foci

Cutaneous leishmaniasis (CL) occurring due to Leishmania tropica is a public health problem in Morocco. The distribution and incidence of this form of leishmaniasis have increased in an unusual way in the last decade, and the control measures put in place are struggling to slow down the epidemic. This study was designed to assess the impact of climatic and environmental factors on CL in L. tropica foci. The data collected included CL incidence and climatic and environmental factors across three Moroccan foci (Foum Jemaa, Imintanout, and Ouazzane) from 2000 to 2019. Statistical analyses were performed using the linear regression model. An association was found between the occurrence of CL in Imintanout and temperature and humidity (r² = 0.6076, df = (1.18), p-value = 3.09 × 10⁻⁵; r² = 0.6306, df = (1.18), p-value = 1.77 × 10⁻⁵). As a second objective of our study, we investigated the population structure of L.tropica in these three foci, using the nuclear marker internal transcribed spacer 1 (ITS1). Our results showed a low-to-medium level of geographic differentiation among the L.tropica populations using pairwise differentiation. Molecular diversity indices showed a high genetic diversity in Foum Jemaa and Imintanout; indeed, 29 polymorphic sites were identified, leading to the definition of 13 haplotypes. Tajima’s D and Fu’s F test statistics in all populations were not statistically significant, and consistent with a population at drift–mutation equilibrium. Further analysis, including additional DNA markers and a larger sample size, could provide a more complete perspective of L. tropica’s population structure in these three regions. In addition, further research is needed to better understand the impact of climatic conditions on the transmission cycle of Leishmania, allowing both for the development of effective control measures, and for the development of a predictive model for this parasitosis.

Distribution and epidemiological features of cutaneous leishmaniasis in Asir province, Saudi Arabia, from 2011 to 2020

BACKGROUND

Cutaneous leishmaniasis (CL) places a major burden on the health authorities in Saudi Arabia. Information about the geographical reach and seasonality of CL in Asir province remains limited. Therefore, this study aimed to investigate the epidemiological features of CL in southwest Saudi Arabia.

METHODS

Retrospective data from CL patients was collected from the regional vector control unit in Asir province over 9 years. Information analysis was performed using R statistic language (version 4.0.5) and the spatial distribution of cases was mapped using QGIS (version 3.20.0).

RESULTS

A total of 1565 CL cases were recorded from 2011 to 2020. Saudi male citizens were at the highest risk of CL infection. However, children under the age of 13 years were most at risk of contracting CL. CL lesions were primarily located on the face and most cases were reported in the winter and autumn seasons. Spatially, the governates of Abha, Sarat-Abidah and Khamis-Mushait had the highest CL infection prevalence. Moreover, a geographical expansion of CL from Abha to Khamis-Mushait governate was noted during past ten years.

CONCLUSIONS

This is the first large scale study to investigate the seasonality, spatial distribution and demographics of CL in Asir province. It describes how the geographical change of CL incidence differs in Asir province and reveals those people most at of CL infections. This study highlights the importance of incorporating improved living conditions, school education and public awareness in the development of CL control policies.

Inflammatory Nasal Swelling due to Leishmania tropica

Since its discovery in the 19th century, cutaneous leishmaniasis has been a major public health problem, especially with the appearance of more and more unusual cases of cutaneous lesions due to this parasite. Indeed, the present study joins the previous studies and describes a typical case of a nasal lesion due to Leishmania infection. This is a 20-year-old young man, with no particular pathological history, from an epidemic focus who presented with inflammatory nasal swelling similar to a mucocutaneous form. However, the X-ray data showed that no lysis of the bones proper to the nose was detected and no damage to the underlying mucosa was observed. Nevertheless, the parasitological diagnosis confirmed the presence of amastigotes, and the results of the molecular study showed that the electrophoretic profile was comparable to that of L. tropica. After diagnosis and confirmation, treatment with meglumine antimonate at the rate of two ampoules/injection (one ampoule = 5 ml) of antimony salt for one month was administered intramuscularly with favorable outcome. Atypical forms of cutaneous leishmaniasis constitute a rare and unusual entity often leading to diagnostic delay. For this, the clinical examination must take into account both exceptional presentations of Leishmania infection, in particular in subjects living or having stayed in an endemic area, in order to ensure appropriate and early treatment.

Impact of Modifiable Risk Factors on the Occurrence of Cutaneous Leishmaniasis in Diyala, Iraq: Case-Control Study

BACKGROUND

In 2018, an outbreak of cutaneous leishmaniasis (CL) occurred in Diyala Province in Iraq. Several risk factors of CL were identified in a prior study; however, the impact of removing modifiable risk factors on the occurrence of the disease was not measured.

OBJECTIVE

The aim of this study is to measure the impact of removing modifiable risk factors of CL on the occurrence of the disease.

METHODS

We conducted a population-based unmatched case-control study in two conveniently selected districts in Diyala Province. All cases of CL were included. Controls were chosen preferentially according to the site where the cases occurred. A structured questionnaire was used to collect data. The unadjusted odds ratios (ORs) and 95% confidence intervals for each risk factor were calculated using binary logistic regression. We also calculated the attributable fractions and 95% confidence intervals of the modifiable risk factors. A P value <.05 was considered statistically significant.

RESULTS

Data from 844 persons (432 cases, 51.2%) were analyzed. Cases were more likely than controls to report a history of previous displacement (OR 5.18, 95% CI 3.84-6.98), electricity supply for less than 12 hours per day (OR 1.94, 95% CI 1.47-2.55), living in a rural area (OR 1.91, 95% CI 1.45-2.51), living in a clay house (OR 2.41, 95% CI 1.59-3.66), having an unpainted indoor living space (OR 2.14, 95% CI 1.51-3.02), having rodents inside the house (OR 5.15, 95% CI 3.56-7.47), having chickens, sheep, or both (OR 3.44, 95% CI 2.48-4.75), having a mixture of dogs and sheep or of dogs and chickens within a distance of less than 100 meters (OR 3.92, 95% CI 2.59-5.94), fogging (OR 2.11, 95% CI 1.40-3.19), bed net use (OR 1.72, 95% CI 1.08-2.72), and sleeping outside or a mixture of inside and outside (OR 4.01, 95% CI 1.32-12.19). The data show that the exposure of approximately 70% to 80% of cases was associated with displacement, the presence of rodents inside the house, the presence of animals within 100 meters of the house, the presence of animals (chickens/sheep/both or a mixture of dogs and sheep or of dogs and chickens), and sleeping outside. Approximately 40%-50% of the cases reported living in a clay house, living in a rural area, having an unpainted indoor space, having an electricity supply for less than 12 hours, and using a bed net.

CONCLUSIONS

Prevention and control of CL requires a multifaceted approach that relies on changing environmental conditions, housing conditions, and human behavior. Fogging and bed net use were not effective because the underlying housing characteristics and human behavior provided a good culture for the disease. We recommend conducting a study to identify the species, reservoirs, and vectors of CL in Iraq; studying vector behaviors before applying environmental control measures; and educating the public on how and when to use bed nets as well as how to accompany their use with behavioral changes.

Diversity and Bionomics of Sandflies (Diptera: Psychodidae) of an Endemic Focus of Cutaneous Leishmaniasis in Zagora Province, Southeast of Morocco

The diversity and seasonality for sandflies were studied in 2019 at a focus of zoonotic cutaneous leishmaniasis in Zagora province, southern Morocco. Standardized sampling with CDC light traps was used. A total of 4504 sandflies (4024 Phlebotomus and 480 Sergentomyia) was collected during the study period. Seven species belonging to genus Phlebotomus and six species of genus Sergentomyia were identified. The most abundant species were Ph. papatasi (33.6%) and Ph. longicuspis (25.7%), highlighting the risk for local disease transmission foci. The seasonal activity of sandflies extended from April to November, showing two peaks, one in June-July and one, less important, in late-September-October. Abundance was highest during the months May, June, and July and lowest in August, September, and October. Results of this study provide important baseline data for planning control interventions.

Cartography and Epidemiological Study of Leishmaniasis Disease in Sefrou Province (2007-2010), Central North of Morocco

Increasing cases of leishmaniasis disease have been reported during recent years in Sefrou Province, Central North of Morocco. This study presents the epidemiological profile of the provincial population, aims at analyzing the epidemiological profile, and in particular, spatiotemporal follow-up of all cases of leishmaniasis. It is a retrospective analysis of leishmaniasis cases recorded between 2007 and 2010. The data were analyzed by SPSS software (version 20). Over a four-year period, from 2007 to 2010, there were 62 cases of leishmaniasis, 93.12% of cases of cutaneous leishmaniasis and 6.87% of visceral leishmaniasis. The case number of leishmaniasis in the Province of Sefrou varies between 0.165% and 0.0018%. For each type of leishmaniasis, the female sex was the most affected compared to the male sex. This difference cannot be considered statistically significant (χ2 = 0.083, p value = 0.77). For cutaneous leishmaniasis, all age groups were affected with a large percentage: patients aged 0–9 years with 63.11% followed by the age group [10–19] with 24.18%. Visceral leishmaniasis mainly has affected the infant population [0–9] with 83.33%. We have not observed any association between the age classes and the leishmaniasis type (χ2 = 6.20, p value = 0.4). From a spatial point of view, the majority of cases of leishmaniasis was reported in El Menzel region (67 cases) followed by Sefrou (64 cases) and Tazouta (38 cases). There is a statistically significant relationship between the type of leishmaniasis and the studied regions (χ2 = 52; p value <0.001). The study of the epidemiological profile of leishmaniasis cases may be useful in enlightening health authorities to develop screening, treatment, and control strategies to reduce the incidence rate of the disease. Other research studies can be conducted to the dynamics of the vectors of sandflies and their ecology.

Spatial dynamics and socioeconomic factors correlated with American cutaneous leishmaniasis in Pernambuco, Brazil from 2008 to 2017

INTRODUCTION:

American cutaneous leishmaniasis (ACL) is a public health problem and has been associated with country’s territory. We aimed to analyze the spatial dynamics and socioeconomic factors correlated to the incidence of ACL in Pernambuco, Brazil from 2008 to 2017.

METHODS:

A cross-sectional, ecological study was conducted in the Brazilian municipalities. Patient data were obtained from the Health Hazard Notification System (SINAN); indicators and incidence for the total period and for quinquennium were obtained. Socioeconomic factors were analyzed to evaluate the association between the incidence of ACL and presence of bathroom and running water, garbage collection availability, inadequate water supply, sanitation, rural population, per capita income, and vulnerability to poverty. Spatial analysis considered the gross incidence; the Bayesian local empirical method and Moran spatial autocorrelation index were applied using Terra View and QGIS.

RESULTS:

The incidence of ACL reduced (0.29/100,000 inhabitants per year). Individuals with ACL were young adults (30.3%), men (60.2%), brown skinned (62.9%), rural residents (70.6%), and less educated (46.7%); had autochthonous transmission (78.8%); developed the cutaneous form (97.2%); had evolution to cure (82.7%); and were diagnosed using the clinical epidemiological criterion (70.5%). ACL occurred in the large part of the state and showed heterogeneous distribution, with persistence of two high priority intervention clusters covering Health Regions I, II, III, IV, and XII.

CONCLUSIONS:

Spatial analysis and epidemiological indicators complement each other. The combination of these methods can improve the understanding on ACL occurrence, which will help subsidize planning and enhance the quality and effectiveness of healthcare interventions.

Identification of trypanosomatids and blood feeding preferences of phlebotomine sand fly species common in Sicily, Southern Italy

In this study, the presence of Leishmania DNA and blood feeding sources in phlebotomine sand fly species commonly present in Sicily were investigated. A total of 1,866 female sand flies including 176 blood fed specimens were sampled over two seasons in five selected sites in Sicily (southern Italy). Sergentomyia minuta (n = 1,264) and Phlebotomus perniciousus (n = 594) were the most abundant species at all the sites, while three other species from the genus Phlebotomus (i.e., P. sergenti n = 4, P. perfiliewi n = 3 and P. neglectus n = 1) were only sporadically captured. Twenty-eight out of the 1,866 (1.5%) sand flies tested positive for Leishmania spp. Leishmania tarentolae DNA was identified in 26 specimens of S. minuta, while the DNA of Leishmania donovani complex was detected in a single specimen each of S. minuta and P. perniciosus. Interestingly, seven S. minuta specimens (0.4%) tested positive for reptilian Trypanosoma sp. Blood sources were successfully identified in 108 out of 176 blood fed females. Twenty-seven out of 82 blood sources identified in fed females of P. perniciosus were represented by blood of wild rabbit, S. minuta mainly fed on humans (16/25), while the sole P. sergenti fed specimen took a blood meal on rat. Other vertebrate hosts including horse, goat, pig, dog, chicken, cow, cat and donkey were recognized as blood sources for P. perniciosus and S. minuta, and, surprisingly, no reptilian blood was identified in blood-fed S. minuta specimens. Results of this study agree with the well-known role of P. perniciosus as vector of L. infantum in the western Mediterranean; also, vector feeding preferences herein described support the hypothesis on the involvement of lagomorphs as sylvatic reservoirs of Leishmania. The detection of L. donovani complex in S. minuta, together with the anthropophilic feeding-behaviour herein observed, warrants further research to clarify the capacity of this species in the transmission of pathogens to humans and other animals.

Possible introduction of Leishmania tropica to urban areas determined by epidemiological and clinical profiles of patients with cutaneous leishmaniasis in Casablanca (Morocco)

Leishmaniases are a group of infectious diseases caused by protozoan Leishmania parasites and are transmitted by the bites of infected phlebotomine sandflies. The heterogeneity of these diseases is influenced by both parasitic properties and host factors. Cutaneous leishmaniasis (CL) is a major public health problem in Morocco, where the geographical expansion of CL (particularly CL caused by Leishmania tropica), the heterogeneous appearance of lesions and the difficulty in diagnosing CL contribute to late diagnosis of CL and delayed treatment of patients. Therefore, the main objective of this study was to describe the epidemiological and clinical profiles of patients with CL diagnosed in Casablanca (Morocco), which is a non-endemic area for CL. A cross-sectional study was conducted between 2010 and 2016, during which epidemiological and clinical data were collected from patients that met the inclusion criteria through an information sheet. Then, samples were obtained from each patient for parasitological and molecular diagnosis, and only patients with positive polymerase chain reaction and genotyping results were included in the study. Overall, 106 cases of CL were genotyped, of which 61 (57.5%) were caused by L. tropica, 38 (35.9%) by L. major and 7 (6.6%) by L. infantum. While all age groups were affected, CL cases wherein L. tropica was the causative agent were most frequently diagnosed in children aged 0–9 years (p = 0.005), whereas those caused by L. major were more frequently diagnosed in elderly patients (p = 0.004). Multivariate logistic regression analysis showed that two clinical variables were significantly associated with CL caused by L. tropica: lesion size (p = 0.002) and occurrence of lesion on the face (p = 0.005). Furthermore, the results of our survey highlighted the association of Leishmania infection when travelling to endemic areas. The high number of endemic foci where patients with CL were infected with L. tropica illustrated the tendency of this form to spread and generate epidemics, exposing young people to a greater degree to the disease. The epidemic status of CL caused by L. tropica in Morocco and the increased movement of the population from rural to urban areas indicate a possible introduction of this species to urban areas.

Environmental and socioeconomic risk factors associated with visceral and cutaneous leishmaniasis: a systematic review

We performed a systematic review of the literature published since 1900 about leishmaniasis a neglected vector-borne disease, focused on environmental and social risk factors for visceral (VL) and cutaneous leishmaniasis (CL) to better understand their impact on the incidence of disease. The search terms were "leishmaniasis" AND "risk factors" using Google Scholar, PudMed, and Scielo. We reviewed 177 articles, 95 studies for VL, 75 for CL, and 7 on both forms. We identified 14 categories of risk factors which were divided into three groups: socioeconomic (7), environmental (5), and climate (2) variables. Socioeconomic factors were also associated with disease incidence in vulnerable human populations of arid and tropical developing regions. Environmental and climate factors showed significant associations with the incidence of VL and CL in all the studies that considered them. Proximity to natural vegetation remnants increased disease risk in both the New and Old World while the climate conditions favorable for disease transmission differed among regions. We propose a common conceptual framework for both clinical forms that highlights networks of interaction among risk factors. In both clinical forms, the interplay of these factors played a major role in disease incidence. Although there are similarities in environmental and socioeconomic conditions that mediate the transmission cycle of tropical, arid, and Mediterranean regions, the behavior of vector and reservoirs in each region is different. Special attention should be given to the possibility of vector adaptation to urban environments in developing countries where populations with low socioeconomic status are particularly vulnerable to the disease.

Leishmaniasis in Northern Morocco: Predominance of Leishmania infantum Compared to Leishmania tropica

In Morocco, Leishmania infantum species is the main causative agents of visceral leishmaniasis (VL). However, cutaneous leishmaniasis (CL) due to L. infantum has been reported sporadically. Moreover, the recent geographical expansion of L. infantum in the Mediterranean subregion leads us to suggest whether the nonsporadic cases of CL due to this species are present. In this context, this review is written to establish a retrospective study of cutaneous and visceral leishmaniasis in northern Morocco between 1997 and 2018 and also to conduct a molecular study to identify the circulating species responsible for the recent cases of leishmaniases in this region. Data concerning leishmaniases cases were collected from the Epidemiology and Disease Control Directorate from 1997 to 2018. Human samples obtained from peripheral laboratories were examined using PCR-ITS1 method. The ITS1 products were subjected to digestion with the restriction endonuclease Mn1-I. Between 1997 and 2018, a total of 1,255 cases of cutaneous and visceral leishmaniasis were recorded in Tangier-Tetouan-Al Hoceima Region, i.e., 1.56% of the reported cases in Morocco (1,255/80,299). Concerning the geographical study covering the period 2007-2018, 79.5% (105/132) of the sectors were affected by leishmaniases. The molecular results showed that Humans were found to be infected with the L. infantum species with a high infection rate compared to L. tropica infection. Moreover, molecular characterization using ITS1 PCR-RFLP showed that the density of L. infantum was significantly higher (n = 68/81; 84%) than that of L. tropica (n = 13/81; 16%) (P-value 9.894e-10). While regarding visceral leishmaniasis, L. infantum was the only species responsible of this form. These findings of this study showed the emergence of L. infantum in Morocco and suggest that this species might be more prevalent than previously thought. Furthermore, the molecular determination of L. infantum will be helpful for control strategies by taking into consideration the reservoir of this species.