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

Genetic diversity in Leishmania infantum and Leishmania tropica isolates from human and canine hosts in northern Morocco

This study investigated nine provinces in northern Morocco and collected 275 skin scraping, 22 bone marrow aspirates, and 89 fine needle aspirations from suspected cutaneous leishmaniasis (CL) and visceral leishmaniasis (VL) patients and potentially infected dogs. Molecular analysis using ITS1 RFLP PCR and RT-PCR revealed a higher prevalence of L. infantum (66.18 %; χ2 = 28.804; df = 1; P-value = 8.01e-08) than L. tropica in skin scraping, with L. infantum being the sole causative agent for both VL and canine leishmaniasis. L. infantum was predominantly found in most provinces, while L. tropica was relatively more dominant in Taza Province. Discriminant Analysis of Principal Components (DAPC) revealed distinct clustering between L. tropica and the other three species. However, no small subset of SNPs could clearly differentiate between Infantum_CL, Infantum_VL, and CanL, as they likely share a significant genetic background. The high rate of L. infantum could be attributed to the abundance of sand fly species transmitting VL. In Taza Province, Phlebotomus sergenti, responsible for anthroponotic CL, is the most abundant species. DNA sequencing demonstrated sequence heterogeneity in L. infantum (variants 1-9) and L. tropica (variants 1-7). Phylogenetic analysis showed a distinct separation between L. tropica and L. infantum strains, with an overlap among L. infantum strains isolated from cutaneous, visceral, and canine cases, and dogs serving as the central population for L. infantum.

Veterinary perspectives on the urbanization of leishmaniosis in Morocco

BACKGROUND

Leishmaniosis caused by Leishmania infantum, L. major and L. tropica is endemic in Morocco. Growing evidence of both human and canine Leishmania infections in urban centres has been reported. Since many forms of the disease are zoonotic, veterinarians play an important role in leishmaniosis control by intervening at the parasite host level. This study aimed to bring together One Health principles to connect canine and feline leishmaniosis epidemiology within urban centres of Morocco (Rabat and Fez) and assess the level of awareness of Moroccan veterinarians about facing this threat.

METHODS

A molecular survey was conducted for Leishmania DNA detection in canine (n = 155) and feline (n = 32) whole-blood samples. Three conventional polymerase chain reaction (PCR) protocols were implemented. The first PCR aimed at identifying infected animals by targeting Leishmania spp. kinetoplast minicircle DNA (kDNA). The second and third PCR targeted the Leishmania internal transcribed spacer region (ITS-1) and the Leishmania small subunit ribosomal RNA (SSUrRNA) gene, respectively, aiming at identification of the infecting species after Sanger sequencing-positive amplicons. Total immunoglobulin G (IgG) against Leishmania spp. was evaluated in 125 dogs by enzyme-linked immunosorbent assays (ELISA) using an in-house protocol, including three Leishmania-specific antigens (SPLA, rKDDR and LicTXNPx). Sera from 25 cats were screened for total IgG to Leishmania spp. by an indirect immunofluorescence antibody test (IFAT). An online questionnaire was presented to Moroccan veterinarians addressing their knowledge and practices towards animal leishmaniosis.

RESULTS

Overall, 19.4% of the dogs tested positive for Leishmania kDNA and ITS-1 and sequencing revealed infection with L. infantum among PCR-positive dogs. These animals presented a wide range of ELISA seropositivity results (16.7%, 34.9% and 51.6%) according to the tested antigens (rKDDR, SPLA and LicTXNPx, respectively). Use of kDNA-PCR revealed 12.5% cats positive to Leishmania spp. otherwise found to be seronegative by IFAT.

CONCLUSIONS

A considerable prevalence of infection was identified in dogs from urban centres of Morocco. Additionally, this is the first report of feline infection with Leishmania spp. in this country and in urban settings. Moroccan veterinarians are aware that animal leishmaniosis is endemic in Morocco, representing a public health threat, and are knowledgeable about canine leishmaniosis diagnosis and treatment.

Isolation and characterisation of Leishmania (Leishmania) infantum from cutaneous leishmaniasis patients in northeast Brazil

BACKGROUND

In Brazil, Leishmania (Leishmania) infantum is a widely distributed protozoan parasite. The human leishmaniasis caused by this species is often associated with visceral form. Tegumentary leishmaniasis (TL) cases due to L. (L.) infantum in the country are considered rare but may be underestimated. Although probably uncommon, these cases represent a new challenge to the prevention and control of leishmaniasis.

OBJECTIVES

Here, we describe two distinct cases of TL with atypical clinical presentations caused by L. (L.) infantum.

METHODS AND FINDINGS

Parasites were isolated from cutaneous lesions of the two patients and typed as L. (L.) infantum after sequencing of the ribosomal DNA internal transcribed spacer. The dermotropic L. (L.) infantum isolates were compared in terms of growth culture patterns, metacyclogenesis and in vitro infectivity in macrophages.

MAIN CONCLUSIONS

This study addresses the emergence of L. (L.) infantum as a causative agent of cutaneous disease in a visceral leishmaniasis hotspot located in northeast Brazil. The data presented provides novel information about the presence of dermotropic L. (L.) infantum in the country and demonstrates the infectivity potential of theses isolates.

Six-Year Study on Cutaneous Leishmaniasis in Al-Muthanna, Iraq: Molecular Identification Using ITS1 Gene Sequencing

BACKGROUND

The current study aimed to determine the prevalence of cutaneous leishmaniasis (CL) in Al-Muthanna province (Iraq) and to characterize the Leishmania species that cause cutaneous lesions through conventional polymerase chain reaction techniques in some patients during the first 7 months of the year 2020.

MATERIALS AND METHODS

Medical information on patients with CL was obtained from archived records at the Al-Muthanna Health Office's Public Health Department (2015-2020). In the Al-Hussein Teaching Hospital laboratory, 95 CL samples were collected and examined microscopically for molecular characterization using Giemsa staining.

RESULTS

Between 2015 and 2020, 2,325 patients (1,184 men and 1,141 women) were enrolled. Although CL occurred across all age groups, those aged range of 5-14 years had the highest proportion of infections (53.0%). This study found that most infections occurred between December and February, peaking in January. Only 63 of 95 CL samples were positive for the Internal Transcribed Spacer 1 region. L. tropica was found in 39 samples (61.9%), whereas L. major was found in 24 samples (38.1%), in CL patients. Although dermal lesions develop in all body regions, a single lesion is the most common. The upper limbs (13 of 16 samples, 33.3%)were infected with L. tropica, whereas the lower limbs (9 of 14 samples, 37.5%) were infected with L. major. In contrast to L. major, most L. tropica lesions occur in urban areas.

CONCLUSION

Our study indicates that CL is endemic in the Al-Muthanna province and that two Leishmania spp. coexist in the province. Molecular diagnosis is a vital component in determining many clinical symptoms of the Leishmania parasite as well as implementing suitable therapeutic, epidemiological, and control strategies.

Entomological, parasitological and molecular investigations in a new focus of cutaneous leishmaniasis in Youssoufia region, Morocco

BACKGROUND AND AIMS

Leishmaniasis is a neglected tropical infection caused by Leishmania parasite that affect human and animal. In Morocco, the cutaneous leishmaniasis has spread substantially to the new areas. The surveillance limited to active foci may underestimate the occurrence of cutaneous leishmaniasis (CL). This study aims to investigate the local transmission of CL in rural districts of Youssoufia province, central Morocco, as a potential focus of CL.

METHODS

For this purpose, parasitological, molecular and entomological investigations were carried out in this area. Data collection concerns potential vectors and human cases. Thus, 402 patients were examined for suspected leishmaniasis lesions in three localities of the province of Youssoufia. In these same localities, 983 sand flies were collected by CDC light traps and sticky paper during one-night per month during 6 months. These sand flies were all identified morphologically using the Moroccan identification key.

RESULTS

The results showed that among the 25 skin lesions detected in a population of 402 individuals, 18 were confirmed by kDNA nested PCR as CL positive patients, of which only 25% were positive by direct examination. Leishmania tropica and Leishmania major were identified as causative agents of CL in the study area. Direct parasitological examination showed a low sensitivity (27.78%), especially for L. major, although its specificity was evaluated at 100%. Regarding entomological results, both genera of the Moroccan sand fly were collected in the study area: Genus/Phlebotomus (75.28%) and Sergentomyia (24.72%). Phlebotomus (P) papatasi, the proven vector of L. major, was the most abundant species (33.98%), followed by Paralongicollum sergenti (22.58%), the confirmed vector of L. tropica; while Sergentomyia (S) minuta, P. longicuspis, S. fallax and P. kazeruni were collected with, respectively, 17.60%, 16.99%, 7.12% and 1.73%.

CONCLUSION

This study constitutes the first report of CL in the study areas, as well as the coexistence of L. tropica and L. major in these rural localities. Local transmission of CL is highly probable, as indicated by the prevalence of the two proven vectors of L. major and L. tropica. To control the spread of this disease, our results suggest the use of highly sensitive molecular methods to detect CL cases in potential leishmaniasis foci, which will improve surveillance.

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.

Determinants of anthroponotic cutaneous leishmaniasis by case-control study in Morocco

Leishmaniasis is endemic in Morocco where both cutaneous and visceral forms coexist. To date, anthroponotic cutaneous leishmaniasis (ACL) determinants remain poorly investigated in Morocco. However, the disease risk factors identification is vital to determine the specific preventive process. In this aim, a case-control study was conducted in the main active ACL foci in central Morocco. Epidemiological data were extracted from bulletins, registers and annual reports of the regional direction of Health offices. The socioeconomic and environmental data were collected from epidemiological surveys, completed by a questionnaire intended for accessible positive population and control people selected from the cases' entourage. The study included 258 cases and 395 controls. Our results showed that many socioeconomic factors were associated with ACL in Morocco such as the rural habitation (OR = 4.163; 95% CI: 2.91-5.96), movement to endemic area (OR = 4.53; 95% CI: 3.03-6.77), provenance from leishmaniasis foci (in Essaouira focus OR = 5.34; 95% CI: 1.19-24.03) and poverty. In addition, environmental factors like proximity of vegetation (OR = 2.45; 95% CI: 1.14-5.25), poor domestic hygiene, particularly the absence of sewage system/waste management (OR = 1.63; 95% CI: 1.35-1.96), and presence of animals (OR = 2.67; 95% CI: 1.14-5.25) increase the risk of ACL in Morocco. Except for Matrimonial status (married people, OR = 4.11; 95% CI: 1.80-9.41), there is however no significant association of the disease with the other socio-demographic factors in the study area (p>0.05). These several risk factors must be taken in consideration to prevent this disease through multidisciplinary collaboration and community participation.

Seasonal Dynamics of Sand Flies (Diptera, Pshycodidae), Vectors of Cutaneous Leishmaniasis, in the City of Fez, Northern Morocco

The infections transmitted by sand flies (Diptera, Psychodidae) pose always a real health problem due to the increasing number of cases detected each year and the annual emergence of new leishmaniasis outbreaks. This study evaluated the temporal evolution of six species of sand flies in five stations inventoried between May 2017 and April 2018, in order to determine for the first time the extent of cutaneous leishmaniasis (CL) transmission in the city of Fez. The monthly impact of Fez sand fly density has been studied using all multivariate statistical analyses, including multiple factor correspondence analysis (MCA), which were performed using XLSTAT and the version of SPSS 20.0 test. Differences between concentrations were considered significant if P < 0.05. To better study the results obtained, different ecological indices have been studied. This study showed that these vectors developed in different sectors of the city of Fez. A total of 816 sand flies were collected from five stations in the city, belonging to three species of the genus Phlebotomus (46.82%) and three species of the genus Sergentomyia (53.18%). The seasonal fluctuation of the average density followed a bimodal evolution for the three stations Dhar Richa, Ain Nokbi, and Boujloud. The stations of Ain Nokbi (0.87 ph/m²) and Dhar Richa (0.467 ph/m²) exposed the sites to a high average density with a maximum peak during August (1.965 ph/m²) and July (1.87 Ph/m²), respectively. S. minuta (44.24%), Ph. sergenti (26.96%), Ph. perniciosus (10.78%), and Ph. papatasi (9.07%) were the most qualified species. The calculated P value is above the 5% significance level, so the relative abundance of these species between study sites shows no significant difference. The period of phlebotomy activity of the genus Phlebotomus in Fez lasts seven months from May to November with a bimodal or trimodal evolution and varies according to the species or the surveyed station. The seasonal fluctuation of sand flies could be conditioned by climatic factors where the period of activity of the species coincides with the hot months (May, June, July, and August). We have observed that the temperature factor favors the prevalence of sand flies, while the difference in the relative abundance of species between the sites is related to the difference in the bioecological conditions of each site.

The Sporadic cutaneous leishmaniasis due to Leishmania infantum in Morocco: A presumably trend towards endemicity

In Morocco, cutaneous leishmaniasis (CL) is an endemic disease; it is considered a major public health problem caused by three species Leishmaniamajor, Leishmaniatropica, and the dermotropic variant MON-24 of Leishmaniainfantum. This species has three incriminated vectors named; Phlebotomus ariasi, Phlebotomus longicuspis and Phlebotomus perniciosus, with the dog as reservoir.The main aim of this review is to elucidate the current epidemiological pattern of CL due to L.infantum and to investigate the factors facilitating its propagation throughout the country. Therefore, the number of CL cases due to L.infantum, their repartition; the distribution of L.infantum vectors, as well as the factors affecting their abundance and spread were investigated. We showed a wide extension of this form of CL, from the north of Morocco to the Saharan areas, as well as an increase of reported cases. This extension of the disease has been accompanied by a juxtaposed spread and a high abundance of confirmed vectors of L. infantum, which are present in almost all bioclimatic zones. In this review, we have highlighted the impact of climate: temperature, humidity, precipitation; vegetation and human activities on the geographical expansion of L. infantum vectors. These abiotic and biotic factors constitute favorable conditions for the increase of vector populations, and their introduction into areas where they did not exist before, and subsequently raise the risk of introduction of this form of cutaneous leishmaniasis into previously free areas. To conclude, CL by L.infantum, traditionally evolving as a sporadic form, is changing to an endemic mode, which seeks more epidemiological studies, and more attention from the health authorities when implementing control programs.

Transmission patterns of Leishmania tropica around the Mediterranean basin: Could Morocco be impacted by a zoonotic spillover?

Cutaneous leishmaniasis (CL) due to Leishmania tropica is a neglected tropical disease characterized by a wide geographical distribution in the Mediterranean basin and is endemic in several of its countries. In addition, the vector Phlebotomus sergenti is abundantly present all around the basin. Its transmission cycle is still subject to debate. In some countries, the presence of an animal reservoir has been confirmed. In Morocco, CL due to L. tropica has risen since the 1980s and has spread widely to become the most abundant form of leishmaniasis in the territory. However, the anthroponotic transmission is so far the only recognized mode, despite recordings of L. tropica infection in animal hosts. In this review article, we assess the situation of CL due to L. tropica in the Mediterranean basin with a focus on Morocco and gather knowledge about any potential zoonotic transmission in the country. A concomitant zoonotic transmission could explain the persistence of the disease in areas where human protective measures combined with vector management did not help reduce the disease burden.

Cutaneous leishmaniasis (CL) due to Leishmania tropica is a neglected tropical disease still considered to be anthroponotic in Morocco despite evidence of zoonotic transmission in other endemic countries of the Mediterranean basin. Its high incidence in the country makes it necessary to investigate whether or not a potential concomitant zoonotic transmission exists alongside the anthroponotic one. Moreover, several reports of natural animal infection have been noted in the country. In this paper, we review how CL due to L. tropica is present around the Mediterranean basin, with a particular focus on the Moroccan foci, and try to unveil the existence of a zoonotic transmission in the area. A deep understanding of the transmission patterns of L. tropica in the region is necessary for the implementation of effective control measures and a better assessment of the disease burden. In addition, the complexity of this neglected disease requires more fundamental and applied research to unveil potential factors involved in its spread.

Canine Leishmaniasis in Morocco: A Descriptive Prospective Clinical Study

Canine leishmaniasis (CanL) is a zoonotic vector-borne disease that is endemic in the Mediterranean Basin including Morocco. Dogs play a major epidemiological role in this zoonosis as reservoir hosts. This study investigated the clinical manifestations of CanL in dogs naturally infected with Leishmania infantum. A total of 96 dogs presented to the Small Animal Clinic of the Hassan II Agronomy and Veterinary Institute (IAV Hassan II) of Rabat, Morocco, and were tested by RT-PCR and/or serology. Among them, 32 (33.3%) were positive to Leishmania infantum infection. The majority of the positive dogs (93.7%) came from urban areas. Most of them were male (62.5%) and purebreds (65.6%), were aged between 3 and 7 years (71.8%), and had outside activities (guarding, hunting, livestock guarding, and service activities) (71.8%) and all of them were living exclusively outdoor or had free access to the outdoor environment. Lymphadenomegaly (81.2%), dermatological disorders (65.6%) (mostly exfoliative dermatitis), weight loss (59.3%), exercise intolerance (56.2%), anorexia (28.1%), hyporexia (15.6%), and ocular lesions (28.1%) were the most frequent clinical signs and complaints recorded. Anemia and hyperproteinemia due to hyperglobulinemia were observed in 68.7% and 72.7% of the cases, respectively. These results suggest that CanL leads to various nonspecific clinical signs as described previously, making the diagnosis challenging. Since CanL is endemic in Morocco, it should be recommended to systematically test dogs displaying clinical signs compatible with this disease and to regularly screen asymptomatic at-risk dogs. It is also crucial to educate dog owners about the zoonotic aspect of the disease and to encourage intersectorial collaboration following the “One Health” concept, in order to contribute to a more effective control/prevention of human and canine leishmaniasis.

Leishmaniasis: where are we and where are we heading?

Leishmaniasis is a zoonotic disease in humans caused by the bite of a parasite-infected sandfly. The disease, widely referred to as "poor man's disease," affects millions of people worldwide. The clinical manifestation of the disease depends upon the species of the parasite and ranges from physical disfigurement to death if left untreated. Here, we review the past, present, and future of leishmaniasis in detail. The life cycle of Leishmania sp., along with its epidemiology, is discussed, and in addition, the line of therapeutics available for treatment currently is examined. The current status of the disease is critically evaluated, keeping emerging threats like human immunodeficiency virus (HIV) coinfection and post kala-azar dermal leishmaniasis (PKDL) into consideration. In summary, the review proposes a dire need for new therapeutics and reassessment of the measures and policies concerning emerging threats. New strategies are essential to achieve the goal of leishmaniasis eradication in the next few decades.

The Cutaneous Leishmaniasis and the Sand Fly: Knowledge and Beliefs of the Population in Central Morocco (El Hajeb)

Background

Cutaneous leishmaniasis is a neglected parasitic dermal disease transmitted to humans through the bite of an infected female sand fly. Morocco hopes to eliminate all forms of leishmaniasis by 2030. These dermatoses pose a real public health problem in the country. Although the information is available on the disease, individual knowledge of cutaneous leishmaniasis and sand fly is not yet developed. Exploring people's beliefs and popular behaviours about cutaneous leishmaniasis and its vector allows health officials to know the sociocultural aspects of the disease and to improve prevention and control actions.

Objectives

To identify the knowledge of cutaneous leishmaniasis and its vector in the population in central Morocco.

Methods

Based on the epidemiological data of leishmaniases in the province of El Hajeb, we conducted a field survey and personal interviews in April and May 2019, among 281 persons belonging to the localities where leishmaniases were registered.

Results

Our results show that the participants use the concept of "Chniwla" (61.6%) for sand fly and the concept of "Hboub Chniwla" (50.8%) for cutaneous leishmaniasis; 24.6% of the respondents do not know how the disease is transmitted to humans and 43.7% use traditional treatments and home remedies to cure themselves. 44% of participants believe that sand fly does not transmit the disease to humans and only 6.4% were aware of their responsibility in vector control.

Conclusions

The study concluded that there is a need to simplify the scientific terminology in the health education of citizens regarding these dermatoses and their vector by integrating the popular concepts obtained in this study to raise public awareness and facilitate their involvement as active actors in the prevention of cutaneous leishmaniasis.

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.

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.