Natural infection of Phlebotomus (Larroussius) langeroni (Diptera: Psychodidae) with Leishmania infantum in Tunisia

Perspectives of vector management in the control and elimination of vector-borne zoonoses

The complex transmission profiles of vector-borne zoonoses (VZB) and vector-borne infections with animal reservoirs (VBIAR) complicate efforts to break the transmission circuit of these infections. To control and eliminate VZB and VBIAR, insecticide application may not be conducted easily in all circumstances, particularly for infections with sylvatic transmission cycle. As a result, alternative approaches have been considered in the vector management against these infections. In this review, we highlighted differences among the environmental, chemical, and biological control approaches in vector management, from the perspectives of VZB and VBIAR. Concerns and knowledge gaps pertaining to the available control approaches were discussed to better understand the prospects of integrating these vector control approaches to synergistically break the transmission of VZB and VBIAR in humans, in line with the integrated vector management (IVM) developed by the World Health Organization (WHO) since 2004.

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.

Phlebotomine sand flies (Diptera: Psychodidae) of the Maghreb region: A systematic review of distribution, morphology, and role in the transmission of the pathogens

BACKGROUND

Phlebotomine sand flies (Diptera: Psychodidae) are important vectors of various human and animal pathogens such as Bartonella bacilliformis, Phlebovirus, and parasitic protozoa of the genus Leishmania, causative agent of leishmaniases that account among most significant vector-borne diseases. The Maghreb countries Mauritania, Morocco, Algeria, Tunisia, and Libya occupy a vast area of North Africa and belong to most affected regions by these diseases. Locally varying climatic and ecological conditions support diverse sand fly fauna that includes many proven or suspected vectors. The aim of this review is to summarize often fragmented information and to provide an updated list of sand fly species of the Maghreb region with illustration of species-specific morphological features and maps of their reported distribution.

MATERIALS AND METHODS

The literature search focused on scholar databases to review information on the sand fly species distribution and their role in the disease transmissions in Mauritania, Morocco, Algeria, Tunisia, and Libya, surveying sources from the period between 1900 and 2020. Reported distribution of each species was collated using Google Earth, and distribution maps were drawn using ArcGIS software. Morphological illustrations were compiled from various published sources.

RESULTS AND CONCLUSIONS

In total, 32 species of the genera Phlebotomus (Ph.) and Sergentomyia (Se.) were reported in the Maghreb region (15 from Libya, 18 from Tunisia, 23 from Morocco, 24 from Algeria, and 9 from Mauritania). Phlebotomus mariae and Se. africana subsp. asiatica were recorded only in Morocco, Ph. mascitti, Se. hirtus, and Se. tiberiadis only in Algeria, whereas Ph. duboscqi, Se. dubia, Se. africana africana, Se. lesleyae, Se. magna, and Se. freetownensis were reported only from Mauritania. Our review has updated and summarized the geographic distribution of 26 species reported so far in Morocco, Algeria, Tunisia, and Libya, excluding Mauritania from a detailed analysis due to the unavailability of accurate distribution data. In addition, morphological differences important for species identification are summarized with particular attention to closely related species such as Ph. papatasi and Ph. bergeroti, Ph. chabaudi, and Ph. riouxi, and Se. christophersi and Se. clydei.

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.

Investigation of natural infection of Phlebotomine (Diptera: Psychodidae) by Leishmania in Tunisian endemic regions

Leishmaniases are caused by protozoan parasites of the genus Leishmania transmitted by females blood-feeding phlebotomine insects (Diptera: Psychodidae). In Tunisia, cutaneous and visceral leishmaniases are of public health concern. In Tunisia, 17 species of phlebotomine sand flies are described. Here we investigate natural infection in Tunisian mixed foci regions of leishmaniases. We trap female sandflies during the Leishmania transmission season in the country's central-eastern and northern parts. We investigate Leishmania infection using PCR-RFLP targeting the ITS1 ribosomal DNA, followed by enzymatic digestion with HaeIII; then, we identify sand flies using molecular methodologies. We confirm the presence of Phlebotomus papatasi and Phlebotomus perniciosus infected by L. major and L. infantum parasites in Tunisia.

Potential distributions of phlebotomine sandfly vectors of human visceral leishmaniasis caused by Leishmania infantum in Morocco

Zoonotic visceral leishmaniasis is a common vector-borne systemic disease caused by Leishmania infantum (Kinetoplastida: Trypanosomatidae). In Morocco the situation is complex: many sandfly species have been collected in areas in which the disease is endemic, but only Phlebotomus ariasi, Phlebotomus perniciosus and Phlebotomus longicuspis (Diptera: Psychodidae) have been confirmed to have vectorial roles. The objective of the present study was to ascertain the potential distribution of L. infantum and its vectors in Morocco, using ecological niche modelling. Vector records were obtained from field collections of the Laboratory team and from previously published entomological observations. Epidemiological data for L. infantum modelling were obtained from Moroccan Ministry of Health reports. The jackknife test indicated that the bioclimatic variables with the greatest influence on model development for all species were annual precipitation and precipitation in the driest quarter of the year. MaxEnt model representations for sandfly species that act as vectors of L. infantum showed the widespread geographic distribution of these species in Morocco, specifically in northern and central Morocco, where foci of visceral leishmaniasis are found. The ecological niche modelling points out areas in which the probability of occurrence of these species is higher. This information should be considered as a starting point for further research to fully elucidate the ecology and epidemiology of these species, as well as of the pathogens they transmit.

Co-circulation of Toscana virus and Leishmania infantum in a focus of zoonotic visceral leishmaniasis from Central Tunisia

In the Mediterranean basin, sand flies are vectors of Leishmania parasites and phleboviruses affecting humans and animals. In this study, we aimed to investigate phlebovirus and Leishmania parasites circulating in a focus of zoonotic visceral leishmaniasis (ZVL) located in a highly irrigated area within the arid Central Tunisia, known mainly to be endemic for zoonotic cutaenous leishmaniasis (ZCL) caused Leishmania major and transmitted by Phlebotomus papatasi. Sand flies were collected using CDC light traps in the village of Saddaguia, an emergent focus of ZVL located in Central Tunisia during September-October 2014, 2015, and 2016. Pools of live female sand flies were screened for phleboviruses and Leishmania by nested PCR in the polymerase gene and kinetoplast minicircle DNA, respectively. Dead sand flies were identified morphologically to species level. Sand flies of the subgenus Larroussius mainly Phlebotomus perfiliewi, Phlebotomus perniciosus, and Phlebotomus longicuspis were predominant in this ZVL focus compared to P. papatasi. A total of 1932, 1740, and 444 sand flies were tested in 2014, 2015 and 2016, respectively. Pathogen screening performed on 4116 sand flies distributed in 148 pools revealed the presence of Leishmania infantum and Toscana virus. The minimum infection rates of sand flies with TOSV in 2014, 2015, and 2016 were 0.05%, 011%, and 0.22%, respectively. The minimum infection rates of sand flies with L. infantum in 2014, 2015, and 2016 were 0.25%, 012%, and 0.79%, respectively. No L. major was detected during the 3-years investigation in this ZVL focus. Our results showed clearly the endemic co-circulation of TOSV and L. infantum in this emergent ZVL focus. However, no co-infection of TOSV and L. infantum was detected in any of the sand fly pools investigated during the three years period. TOSV was isolated from positive pools in 2015. Phylogenetic analysis showed that the Tunisian strains of TOSV belonged to the sublineage A. Based on the present findings, our results provided strong evidence that TOSV and L. infantum are transmitted by the same predominant sand fly species of the subgenus Larroussius, and subsequently, humans and dogs could be co-infected through co-infected or successive infected bites. Our results showed clearly that the development of irrigation in arid areas contributed significantly to the establishment of stable transmission cycles of L. infantum and TOSV and subsequently to the emergence of a ZVL focus within this arid bio-geographical area characterized by the presence of multiple foci of ZCL located outside the study site. Thus, more studies are needed to better understand the impact of RNA viruses shared by vectors and reservoir hosts of L. infantum on the development of zoonotic visceral leishmaniasis.

Molecular detection and identification of Leishmania DNA and blood meal analysis in Phlebotomus (Larroussius) species

BACKGROUND

Phlebotomus (Larroussius) perniciosus and Canis familiaris are respectively the only confirmed vector and reservoir for the transmission of Leishmania (L.) infantum MON-1 in Tunisia. However, the vector and reservoir hosts of the two other zymodemes, MON-24 and MON-80, are still unknown. The aim of this study was to analyze the L. infantum life cycle in a Tunisian leishmaniasis focus. For this purpose, we have focused on: i) the detection, quantification and identification of Leishmania among this sand fly population, and ii) the analysis of the blood meal preferences of Larroussius (Lar.) subgenus sand flies to identify the potential reservoirs.

METHODOLOGY AND FINDINGS

A total of 3,831 sand flies were collected in seven locations from the center of Tunisia affected by human visceral leishmaniasis. The collected sand flies belonged to two genus Phlebotomus (Ph.) (five species) and Sergentomyia (four species). From the collected 1,029 Lar. subgenus female sand flies, 8.26% was positive to Leishmania by ITS1 nested PCR. Three Leishmania spp. were identified: L. infantum 28% (24/85), L. killicki 13% (11/85), and L. major 22% (19/85). To identify the blood meal sources in Ph. Lar. subgenus sand flies, engorged females were analyzed by PCR-sequencing targeting the vertebrate cytochrome b gene. Among the 177 analyzed blood-fed females, 169 samples were positive. Sequencing results showed seven blood sources: cattle, human, sheep, chicken, goat, donkey, and turkey. In addition, mixed blood meals were detected in twelve cases. Leishmania DNA was found in 21 engorged females, with a wide range of blood meal sources: cattle, chicken, goat, chicken/cattle, chicken/sheep, chicken/turkey and human/cattle. The parasite load was quantified in fed and unfed infected sand flies using a real time PCR targeting kinetoplast DNA. The average parasite load was 1,174 parasites/reaction and 90 parasites/reaction in unfed and fed flies, respectively.

CONCLUSION

Our results support the role of Ph. longicuspis, Ph. perfiliewi, and Ph. perniciosus in L. infantum transmission. Furthermore, these species could be involved in L. major and L. killicki life cycles. The combination of the parasite detection and the blood meal analysis in this study highlights the incrimination of the identified vertebrate in Leishmania transmission. In addition, we quantify for the first time the parasite load in naturally infected sand flies caught in Tunisia. These findings are relevant for a better understanding of L. infantum transmission cycle in the country. Further investigations and control measures are needed to manage L. infantum transmission and its spreading.

Transmission cycle analysis in a Leishmania infantum focus: Infection rates and blood meal origins in sand flies (Diptera: Psychodidae)

An entomological study was conducted in a Leishmania infantum focus, including the identification of the sand fly species, the detection and the characterization of Leishmania DNA in female sand flies, and blood meal origins in engorged sand flies. A total of 643 sand flies (31% female, 69% male) was identified based on their morphological features or molecular markers. Ten different species were identified, with Phlebotomus perniciosus, the confirmed vector of L. infantum, being the most abundant (56%), P. papatasi in 25% of sand flies, the unique vector species of L. major, and P. longicuspis in 7% of cases, the suspected second vector of L. infantum. Moreover, the infection rate was 3.4% in P. perniciousus, P. papatasi, P. longicuspis, and Sergentomya minuta. Also, L. infantum was identified in five unfed P. perniciosus and two P. longicuspis. Our results suggest the vector role of P. perniciosus and P. longicuspis in the transmission cycle of L. infantum. The DNA of four mammalian species (human, rabbit, horse, and cow) was identified in the blood meals of sand flies, suggesting that these species are potential reservoirs of leishmaniasis, though it is not yet fully elucidated (especially for MON-24 and MON-80). We suggest the existence of different transmission cycles of L. infantum involving different species of sand flies and hosts.

The vector competence of Phlebotomus perniciosus for Leishmania infantum zymodemes of Tunisia

Experimental infections of Phlebotomus (L.) perniciosus from a colony established in Madrid (Spain) carried out with the Leishmania (L.) infantum zymodemes MON-1, MON-24, and MON-80 isolated in Tunisia are reported here. Laboratory-reared female sand flies were experimentally fed via membrane feeding device on a suspension of L. infantum promastigotes in defibrinated rabbit blood (10⁷/ml). Engorged females were dissected at progressive time points postfeeding to observe the intravectorial cycle of different L. infantum zymodemes. Development in the sand fly midgut of L. infantum parasites to the infective metacyclic promastigotes and monitoring the forward progression of parasites to finally reach the stomodeal valve (SV) of the sand fly were assessed. All tested L. infantum zymodemes developed properly in P. perniciosus. Experimental feeding with suspensions of promastigotes of all zymodemes led to very heavy late-stage infections. MON-24 and MON-80 zymodemes colonized the (SV) of P. perniciosus earlier than zymodeme MON-1, 2 and 4 days, respectively. Metacyclic promastigotes were observed in all experimental infections. The study shows for the first time that colonized P. perniciosus is able to acquire, retain, and develop in its midgut the zymodemes MON-24 and MON-80 isolated in Tunisia and highlights the putative role of this sand fly species in the transmission of such zymodemes to mammalian hosts in this country. The ability of experimentally infected sand fly species to transmit by bite such zymodemes needs to be assessed.

First detection of Leishmania DNA in Psammomys obesus and Psammomys vexillaris: Their potential involvement in the epidemiology of leishmaniasis in Tunisia

Leishmaniasis, a public health problem in Tunisia, are diseases caused by different Leishmania species. Cutaneous leishmaniasis is present from the North to the South under different forms, due to Leishmania (L.) major, L. infantum or L. tropica. Whereas, Psammomys (P.) obesus is the confirmed reservoir host of L. major, those of L. tropica and dermotropic L. infantum wait to be identified. Importantly, P. vexillaris species have been recently highlighted; however, no studies have been carried out to explore its potential role in leishmaniasis epidemiology. Seventy two rodents were collected from Central and South-West of Tunisia between 2007 and 2010. Using several methods, 43 animals were identified as P. obesus and 29 as P. vexillaris. Leishmania kinetoplast DNA was detected in liver samples by real-time PCR in 18 P. obesus and in 8 P. vexillaris. Then, the direct sequencing of the amplified internal transcribed spacer 1, allowed the identification of L. infantum DNA in five P. obesus and in three P. vexillaris, as well as L. tropica DNA in three other P. vexillaris. Whereas, PCR fluorescent fragment length analysis of the 7 spliced leaders, allowed identifying L. major among infected P. obesus and P. vexillaris, and interestingly co-infection (L. major/L. infantum) among two P. obesus. We report here for the first time, the infection of P. obesus, from Central Tunisia, by L. infantum. Suggesting that P. obesus the known reservoir host of L. major, may also serve as reservoir host for L. infantum and thus play a role in the spread of sporadic cutaneous or visceral leishmaniasis in this region. Of equal importance, this work establish for the first time, the natural infection of P. vexillaris by different Leishmania species, suggesting its potential epidemiological role as reservoir host.

Modeling and comparative study of the spread of zoonotic visceral leishmaniasis from Northern to Central Tunisia

During the last twenty years, zoonotic visceral leishmaniasis (ZVL) spread from the north characterized by humid, sub-humid, and semi-arid bio-climates to the arid areas located in Central Tunisia. In order to understand the eco-epidemiological factors involved in the distribution of ZVL, both a sero-epidemiological and an entomological investigation were performed in two governorates situated in two different bio-geographical areas: Bizerte in the north and Kairouan in the center. A mathematical model for transmission of ZVL was built, describing the disease dynamic in these areas. Among 108 sera collected from clinically healthy owned dogs used for guarding houses in the governorate of Bizerte and tested for anti-L. infantum antibodies by indirect immune-fluorescence antibody test (IFAT), 8.3% were positive. From a total of 191 serum samples collected from clinically healthy owned dogs used for guarding houses in the governorate of Kairouan and tested for anti-L. infantum antibodies by IFAT, 26.7% were sero-positive. The cumulative incidences of ZVL in humans in the governorates of Bizerte and Kairouan were 39.17/100,000 and 0.2/100,000 inhabitants, respectively. The infection rates of sand flies with Leishmania DNA in the governorate of Bizerte and Kairouan were 3.8% and 9.4%, respectively. It is important to point out that ZVL epidemic in humans is preceded or concomitant to a high prevalence of Leishmania infantum in dogs and in sand flies. The model showed also a non-linear relationship between dog infection and ZVL in humans. These results suggest an important force of infection (R0) in emerging foci such as the governorate of Kairouan leading to an increased incidence of ZCL in humans. A high prevalence of L. infantum in dogs will result in high prevalence in the vector and obviously high probability to infect human; that it is a key factor for triggering transmission to humans, and subsequently it is an important parameter in the control of ZVL transmission.

Historical overview of infantile visceral leishmaniasis in El Agamy, Alexandria, Egypt

Infantile visceral leishmaniasis (IVL) is considered a rare and neglected disease in Egypt. An outbreak of the disease in El Agamy, Alexandria occurred in 1982 although the disease was previously reported 80 years before. Epidemiological and entomological studies were conducted ever since the 1982 outbreak to identify human cases, the parasite, reservoir host and the sand fly vector. Leishmania infantum MON-98, a new and unique zymodeme, was responsible of the disease. Stray dogs acted as the reservoir host and Phlebotomus langeroni was the proven vector. The parasite isolates from human cases were identical to the parasite isolates from the reservoir host and the sand fly vector. The El Agamy focus in 1982 was basically a rural Bedouin setting of recently built cement houses surrounded by lime stone fences. The numbers of human cases of IVL in this area have been declining, with the last reported case in 2005. This coincides with the completion of irregular urbanization of El Agamy which resulted in the disappearance of P. langeroni. In this review, we characterize the old focus of IVL in El Agamy based on published literature to identify factors underlying the appearance and disappearance of the disease.

Natural infection of Algerian hedgehog, Atelerix algirus (Lereboullet 1842) with Leishmania parasites in Tunisia

In Tunisia, Leishmania parasites are responsible of visceral leishmaniasis, caused by Leishmania infantum species while three cutaneous disease forms are documented: chronic cutaneous leishmaniasis due to Leishmania killicki, sporadic cutaneous form (SCL) caused by L. infantum and the predominant zoonotic cutaneous leishmanaisis (ZCL) due to Leishmania major. ZCL reservoirs are rodents of the Psammomys and Meriones genera, while for SCL the dog is supposed to be a reservoir. Ctenodactylus gundii is involved in the transmission of L. killicki. However, other mammals could constitute potential reservoir hosts in Tunisia and other North African countries. In order to explore the role of hedgehogs as potential reservoirs of leishmaniasis, specimens (N=6) were captured during July-November period in 2011-2013 in an SCL endemic area in El Kef region, North-Western Tunisia. Using morphological characteristics, all specimens were described and measured. Biopsies from liver, heart, kidney and spleen of each animal were used to extract genomic DNA, which was further used in PCR assays to assess the presence of Leishmania parasites. Different PCRs targeting kinetoplast minicircles, ITS1, mini-exon genes and a repetitive Leishmania- specific sequence, were applied. To further identify Leishmania species involved, RFLP analysis of amplified fragments was performed with appropriate restriction enzymes. Using morphological characters, animals were identified as North African hedgehogs, also called Algerian hedgehogs, that belong to the Erinaceidae family, genus Atelerix Pomel 1848, and species algirus (Lereboullet, 1842). PCR results showed in total that all specimens were Leishmania infected, with different organs incriminated, mainly liver and spleen. Results were confirmed by direct sequencing of amplified fragments. Species identification showed that all specimens were infected with L. major, three of which were additionally co-infected with L. infantum. The present study demonstrates, for the first time in Tunisia, natural infection of hedgehog animals (Atelerix algirus) by the Leishmania parasites species L. major and L. infantum. L. major is also detected for the first time in wild animals captured in the North Western part of the country; likewise for the co-infection of these animals by the 2 Leishmania species. This mammal could play a potential reservoir role in epidemiology of SCL or ZCL and could contribute to emergence or extension of ZCL in the studied region.

Interaction between canine and human visceral leishmaniases in a holoendemic focus of Central Tunisia

Canine visceral leishmaniasis (CVL) is endemic in the Mediterranean basin. In Tunisia, CVL is spatially associated with human visceral leishmaniasis (HVL) affecting mostly children younger than 5 years old. In this study, seroprevalence of Leishmania infantum infection in dogs was assessed in highly endemic districts of the governorate of Kairouan where more than 50% of HVL cases in Tunisia were reported. An entomological investigation was also carried out in two endemic districts (Bouhajla and Haffouz) to assess sand fly fauna and infection status of sand flies with Leishmania. A total of 191 serum samples were collected from healthy dogs and tested for anti-L. infantum antibodies by indirect immunofluorescence antibody test (IFAT). Overall seroprevalence for L. infantum was 26.7% being highest among dogs in the district of Bouhajla (52.7%) and the lowest in the district of Chbika (5.2%). In dogs, seroprevalence did not differ significantly based on gender or age, with dogs younger than 1 year showing a higher seroprevalence compared to older dogs. These findings suggest strong force of infection in naïve animals in holoendemic regions leading to emerging high incidence of HVL. Concomitant to the high CVL prevalence observed in the Bouhajla district, a significantly high cumulative HVL incidence also was observed in this district. Phlebotomus perniciosus and Phlebotomus longicuspis were the most abundant sand fly species in Bouhajla and Haffouz districts. The rate of Leishmania-DNA infection in sand flies was 9.4%. This finding points to spatial correlation between the occurrence of disease in humans, a high rate of infection in dogs and a high abundance of P. pernicious and P. longicuspis. Thus, CVL is the main risk factor for transmission to humans and subsequently, it is an important parameter for controlling transmission to humans.

Leishmaniases in Maghreb: an endemic neglected disease

Maghreb is known to be one of the most endemic areas of leishmaniases where both visceral and cutaneous forms are reported. Cutaneous leishmaniasis (CL) is older and has a higher prevalence than visceral one (VL). It is caused by four taxa (Leishmania (L.) major, L. infantum, L. tropica and L. killicki) which are responsible for a large clinical spectrum of lesions. Most transmission cycles of these taxa are known and many phlebotomine sandflies vectors and reservoir hosts are identified. The zoonotic transmission is well established for L. major. However, for L. infantum and L. killicki it needs more investigations to be proven. Regarding L. tropica, studies suggest it to be of both zoonotic and anthroponotic types. The isoenzymatic characterization of these four taxa showed a large enzymatic polymorphism varying from two zymodemes for L. major to 10 zymodemes for L. tropica. Cutaneous leishmaniasis is widely distributed and covers all bioclimatic stages with the coexistence of more than one taxon in the same foci. Visceral leishmaniasis is the second form of leishmaniases in Maghreb. Only L. infantum is known to cause this disease. The transmission cycle of this parasite is zoonotic but still not well known. The isoenzymatic identification of L. infantum causing VL showed the presence of six zymodemes. Geographically, VL is distributed in all bioclimatic stages of Maghreb countries. Despite all the previous studies realized on leishmaniases in Maghreb, they are still considered as neglected diseases because of the rarity or the absence of efficient control strategies.

Transmission of visceral leishmaniasis in a previously non-endemic region of Tunisia: detection of Leishmania DNA in Phlebotomus perniciosus

Visceral leishmaniasis (VL) has been endemic in northern Tunisia and has occurred sporadically in the center of Tunisia. Recently, there have been several cases from areas known to be free of VL. We report in this work all human and canine cases of VL recorded between 2003 and 2011 and an entomological study of phlebotomine fauna in a previously non-endemic region. Sixty-three cases of VL were diagnosed and identified as L. infantum using several different methods. Eight species of 179 sand flies were caught and identified by both morphological and molecular methods. Two genera were present, Phlebotomus and Sergentomya, with an abundance of the subgenus Phlebotomus (Larrousius) spp., a classic vector of VL in Tunisia. Moreover, Leishmania DNA was detected in seven unfed Phlebotomus pernicousus and L. infantum was identified in three of them. This result confirms the establishment of a transmission cycle of VL in the studied region by the coexistence of infected vectors with infected hosts.

Molecular characterization of Leishmania infection in sand flies from Al-madinah Al-munawarah province, western Saudi Arabia

Cutaneous leishmaniasis (CL) is caused by various species of the genus Leishmania. The disease is considered a major health problem in different areas of Saudi Arabia including Al-madinah Al-munawarah province. We aimed to identify Leishmania species isolated from sand fly vectors by molecular analysis. Sand fly sampling was carried out from May 2010 to October 2010 in province of Al-madinah Al-munawarah from four different localities. Female sand flies collected were subjected to DNA extraction followed by molecular analysis using the semi-nested PCR and conventional PCR protocols, respectively, against minicircle kDNA and ribosomal internal transcribed spacer 1 (ITS1-rDNA). The PCR positive specimens against ITS1-rDNA locus were digested for further confirmation of species identification. A total of 2910 sand flies were collected. Phlebotomus papatasi accounted for 93.8% (1673 males and 1057 females), however, the number of Phlebotomus sergenti was only 180 (109 males and 71 females). Sixty-two out of 250 (23.7%) female P. papatasi tested for Leishmania parasite were positive for Leishmania major using the semi-nested PCR method against kDNA. All of the 62 positive specimens produced a band size 650 bp. A 31% of female P. sergenti were positive against kDNA of Leishmania tropica and produced a 720 bp band. These positive P. sergenti for L. tropica DNA produced ITS1-PCR-RFLP profile showed two bands of ∼200 bp and 57 bp which are specific for L. tropica, confirming the presence of L. tropica in P. sergenti. However, the ITS1-PCR-RFLP profile showed two bands of ∼203 bp and 132 bp which are specific for L. major in P. papatasi. We concluded that, the semi-nested PCR method against kDNA and the ITS1-PCR-RFLP analysis are useful tools for molecular identification of both L. major and L. tropica. A multicenter study is necessary in order to evaluate the extent of the disease and functional analysis of new Leishmania genes.

Geographical distribution updating of Tunisian leishmaniasis foci: about the isoenzymatic analysis of 694 strains

Over a period of ten years, a series of 694 Leishmania strains from Tunisian leishmaniasis foci were isolated and identified by isoenzymatic analysis. Strains were obtained from human cutaneous and visceral leishmaniasis in immunocompetent subjects, visceral leishmaniasis in imunocompromised individuals and from dogs with visceral leishmaniasis. Two classically dermotropic species, Leishmania (L.) major and Leishmania killicki were found. L. major with the single zymodeme MON-25 was the most isolated in cutaneous leishmaniasis foci of the Centre and South of Tunisia with a recent northern extension. L. killicki zymodeme MON-8 was sporadically found both in its classical microfocus of Tataouine in southeastern Tunisia as well as in some new foci in Southwestern, Central and Northern Tunisia. Leishmania infantum with its three zymodemes MON-1, MON-24 and MON-80 was isolated from both visceral and cutaneous human cases. The majority of L. infantum strains were found in the Northern part of the country; however, some strains were reported for the first time in the Southern part. L. infantum MON-1 was the only zymodeme isolated from canine leishmaniasis.

Transmission of Leishmania infantum MON-98 to hamsters by the bite of Phlebotomus langeroni Nitzulescu (Diptera: Psychodidae)

The ability of Phlebotomus langeroni to successfully acquire and transmit Leishmania infantum MON-98 to hamsters was demonstrated. Sand flies and Leishmania both originated from an infantile visceral leishmaniasis focus in El Agamy Egypt. P. langeroni females were infected by feeding on lesions of needle-inoculated hamster and on infected blood suspension using a chick-skin membrane apparatus. Infection rate of sand flies fed on membrane was 88% compared to 7.8% for flies fed on leishmanial lesion. The transmission to hamster took place by the bites of infective flies taking a second blood meal, on the 8th to 10th day post-feeding. Furthermore, successful transmission was by the bites of flies that took no blood or that took full blood meal. Whereas flies that took full blood meal were not infective as indicated by dissection. In three hamsters, lesions developed after three months. Leishmania amastigotes were demonstrated from the lesion as well as from the liver and spleen of infected hamsters.

Isoenzymatic variability of Leishmania infantum in Tunisia concerning 254 human strains

The different clinical forms of leishmaniasis are the result of both the immunological status of individuals and the species of the parasite causing the infection. In Mediterranean countries, the Leishmania infantum complex groups zymodemes which are responsible for visceral, cutaneous and exceptionally cutaneomucosal or mucosal leishmaniasis. We report in this study a synthesis concerning 254 cases of L. infantum that have been characterized at the "Laboratoire de Parasitologie" of the Rabta Hospital. The strains were isolated from human cases of visceral leishmaniasis (VL) and cutaneous leishmaniasis (CL) by culture on NNN medium: 156 VL cases and 98 CL cases. The isoenzymatic characterization revealed three zymodemes of L. infantum. * L. infantum MON 1, a common zymodeme of VL,occurred in 154 cases (61%): 147 VL (95%) and 7 CL (5%). All CL cases were from the northern provinces, six of them occurring during an epidemic disease in 2001. * L. infantum MON 24, a common zymodeme of CL in the north, occurred in 98 cases (38.5%): 91 CL (93%) and 7 VL (7%). The seven VL cases were immunocompetent children aged from 8 months to 9 years and native of northern Tunisia. Two of the CL cases were from central regions of the country. This is the first time that cases from these regions are reported. * L. infantum MON 80, an uncommon zymodeme in Tunisia, occurred in two VL cases (0.5%): two children aged 7 and 5. The small number of strains of this zymodeme does not allow understanding of its epidemiological role. The results of this study indicate a low enzymatic variability of L. infantum in the country. However, our study includes only human strains and should be extended to animal ones (dogs, rodents and sand flies). This would lead to a better understanding of the epidemiology of leishmaniasis in Tunisia.