Changes of Sand Fly Populations and Leishmania infantum Infection Rates in an Irrigated Village Located in Arid Central Tunisia

Seroprevalence and Risk Factors Associated with Phleboviruses and Crimean-Congo Hemorrhagic Fever Virus among Blood Donors in Central Tunisia

The aim of this study was to determine the prevalence of six viruses, from two families of the order Bunyavirales, in the general population of central Tunisia. Sera collected from 377 asymptomatic blood donors were serologically assayed for Rift Valley fever virus (RVFV), Crimean-Congo hemorrhagic fever virus (CCHFV), and four sandfly-borne phleboviruses: Toscana virus (TOSV), sandfly fever Naples virus (SFNV), sandfly fever Sicilian virus (SFSV), and sandfly fever Cyprus virus (SFCV). Of the 377 subjects enrolled in this study, 17.3% were IgG positive for at least one of the viruses tested. The most frequently detected antibodies were against TOSV (13.3%), followed by SFCV (2.9%), RVFV (1.9%), SFSV (1.3%), and SFNV (1.1%). Only one sample was IgG positive for CCHFV. Dual reactivity was observed in nine cases: SFSV + SFCV in three cases (0.8%) and TOSV + SFNV, TOSV + SFCV, and TOSV + RVFV in two cases (0.5%) each. 15.9% of donors were IgG positive against sandfly-borne phleboviruses. Among the 65 donors IgG positive for phleboviruses, 50.8% were from rural areas compared to 12.3% from urban areas (p < 0.001); 92.3% had animals in their living quarters (p = 0.009); and 70.8% lived in the vicinity of stagnant water (p = 0.062). Seroprevalence was significantly higher among donors living with chronic diseases (p = 0.039). Furthermore, the seroprevalence of phleboviruses was higher in Kairouan, the central governorate, than in the two coastal governorates: Monastir and Sousse, with 33.4%, 24.2%, and 14.9%, respectively. The presence of antibodies in the general population needs further investigation to better assess the extent of these viruses. Only TOSV was known to have an extensive circulation in Tunisia and in North Africa. Continued surveillance and interventions are necessary to detect the emergence of all arboviruses and to prevent further transmission.

A, Celestino A, Hospinal-Santiani M, de Souza A, Mychalizen M, Borges ME, Piechnik CA. One piece of the puzzle: Modeling vector presence and environment reveals seasonality, distribution, and prevalence of sandflies and Leishmania in an expansion area

The recent geographic spread of Leishmania infantum along the borders of Argentina, Brazil and Paraguay has been highlighted. In our previous study, Lutzomyia longipalpis was found in 55 of 123 patches surveyed, and in some patches, sandflies were found at higher densities, forming hotspots. Based on the One Health approach, we investigated the seasonality of the vector, the presence of parasite DNA, and the environmental factors that contribute to vector and parasite dispersal in these previously described hotspots in Foz do Iguaçu, Brazil. Entomological surveys were conducted monthly for one year. Fourteen hotspots peridomicile and six intradomicile were sampled. PCR was used to assess the prevalence of Leishmania DNA in sandflies. Zero-inflated negative binomial regression was used to determine the association of micro- and mesoscale environmental variables with the occurrence and abundance of the three most abundant sandfly species sampled. A total of 3543 species were captured, with Lutzomyia longipalpis being the predominant species (71.78%) of the 13 species found. Evandromyia edwardsi, Expapillata firmatoi, Micropygomyia ferreirana and Pintomyia christenseni were reported for the first time in the region. NDVI, distance to water, precipitation, west-to-east wind, wind speed, maximum and minimum relative humidity, and sex were significant variables associated with vector presence/abundance in the environment. Vector presence/abundance in the peridomicile was associated with precipitation, altitude, maximum temperature, minimum and maximum relative humidity, west-to-east wind, wind speed, and sex. Leishmania DNA was detected in an average of 21% of Lu. longipalpis throughout the year. Vector abundance is concentrated in urban and peri-urban areas, with some specimens present in different parts of the city and some sites with high vector abundance. This distribution suggests that the risk of actual contact between humans and parasite vectors in urban areas during the epidemic period is associated with patches of peri-urban vegetation and then extends into urban areas.

Blood meal analysis and molecular detection of mammalian Leishmania DNA in wild-caught Sergentomyia spp. from Tunisia and Saudi Arabia

Phlebotomine sand flies (Diptera: Phlebotominae) belonging to the genus Phlebotomus are vectors of pathogens such as arboviruses, bacteria, and parasites (Leishmania). Species of the genus Sergentomyia (Se.) transmit Sauroleishmania (Reptile Leishmania) and feed on cold-blooded vertebrates; recently, they have been incriminated in mammalian Leishmania transmission. In addition, they have been reported to feed on warm-blooded vertebrates. This study aimed to (i) screen wild-caught Sergentomyia species for the detection of mammalian Leishmania and (ii) identify the blood meal origin of engorged females. The sand flies were collected using centers for disease control and prevention (CDC) traps, mounted and identified morphologically. Only females of the genus Sergentomyia were screened for Leishmania infection using PCR targeting the 18S ribosomal DNA locus. For positive specimens, Leishmania parasites were typed using nested PCR targeting ribosomal internal transcribed spacer 1 followed by digestion with HaeIII. The PCR-RFLP results were confirmed through sequencing. Blood meal identification was performed through PCR amplification of the vertebrate cytochrome b gene using degenerate primers followed by sequencing. In total, 6026 sand fly specimens were collected between 2009 and 2018. Among these, 511 belonged to five species of Sergentomyia genus: Se. minuta (58.51%), Se. fallax (18.01%), Se. clydei (14.68%), Se. dreyfussi (6.26%), and Se. antennata (2.54%). A total of 256 female Sergentomyia sp. specimens were screened for Leishmania infection. Seventeen (17) were positive (6.64%). Two Leishmania species were identified. Leishmania major DNA was detected in five specimens; this included three Se. fallax, one Se. minuta, and one Se. dreyfussi collected from Tunisia. Leishmania infantum/L. donovani complex was detected in four Se. minuta and three Se. dreyfussi specimens collected from Tunisia. In addition, we identified the blood meal origin of five engorged Se. minuta specimens collected from Tunisia. Sequencing results revealed two blood sources: humans (n = 4) and reptiles (n = 1) indicating possible role of Sergentomyia species in the transmission of human Leishmania. In addition, these species could be involved in the life cycle of L. infantum/L. donovani complex and L. major. The results of the blood meal origin showed that Sergentomyia fed on both cold- and warm-blooded vertebrates. These findings enable a better understanding of the behavior of this sand fly genus. Further studies should focus on the role of Sergentomyia in human Leishmania transmission and possible control of this disease.

The Role of the Leishmania infantum Infected Dogs as a Potential Reservoir Host for Toscana Virus in a Zoonotic Visceral Leishmaniasis Focus of Northern Tunisia

The role of dogs as reservoir hosts for Toscana virus (TOSV) remains undetermined. This study investigated TOSV and Leishmania infantum infections in one healthy and three infected dogs with Leishmania (A, B, C) following natural exposition to sandfly bites in a focus of zoonotic visceral leishmaniasis (ZVL) located in Northern Tunisia from June to October 2020. At the end of the exposition period, infected and healthy dogs were examined for TOSV and L. infantum infections by xenodiagnosis using a colony of Phlebotomus perniciosus. Pools of freshly engorged P. perniciosus at days 0 and those at days 7 post-feeding were screened for TOSV and L. infantum by nested PCR in the polymerase gene and kinetoplast minicircle DNA, respectively. In the exposure site, P. pernicious is the most abundant sandfly species. The infection rates of sandflies with TOSV and L. infantum were 0.10 and 0.05%, respectively. Leishmania infantum DNA and TOSV RNA were detected in P. perniciosus females fed on dog B and C, respectively. The isolation of TOSV in Vero cells was achieved from two pools containing P. perniciosus fed on dog C. No pathogens were detected in P. perniciosus females fed on dog A and on control dog. We report for the first time the reservoir competence of dog with ZVL in the transmission of TOSV to sandfly vectors in natural settings, in addition to its role as a main reservoir host of L. infantum.

Molecular Characterization of Leishmania Species among Patients with Cutaneous Leishmaniasis in Asir Province, Saudi Arabia

Anthroponotic cutaneous leishmaniais (ACL) and zoonotic cutaneous leishmaniasis (ZCL) caused by Leishmania tropica and Leishmania major, respectively, are endemic vector-borne diseases in southern Saudi Arabia. In 2021, an outbreak of cutaneous leishmaniasis occurred in the province of Asir. The main objective of our investigation was to analyze the epidemiological features of CL in southern Saudi Arabia. The ministry of health recorded 194 CL patients between January and December 2021 from the Asir province. Our findings showed that the majority of CL patients (87.1%) originated from the governorates of Khamis-Mushait and Abha. Most of the patients were males (62.3%). While CL affected all age groups, those under 13 years old were the most affected (38.1%). For both genders, CL patients were mostly Saudi citizens (90.7%) compared to non-Saudi expatriates. The majority of CL patients (75.2%) suffered from a single lesion, and the majority of lesions (61.3%) were located on the face. The seasonal prevalence of CL showed two peaks, a small one in July-August and a larger one in March. Of a total of 194 Giemsa slides samples, 188 showed positive amplification of Leishmania ITS1 gene. Based on PCR-RFLP and PCR-HMR, 183 patients showed positive amplification of L. tropica and five patients showed positive amplification of L. major. Phylogenetic analysis revealed a clear distinct separation between L. major and L. tropica sequences. Our results provided strong evidence of the pre-domination of L. tropica, the main etiological agent of ACL in Asir province. We reported for the first time the presence of L. major, an etiological agent of ZCL in the study areas. The co-circulation of ACL and ZCL highlighted the complexity of the epidemiology of CL in southern Saudi Arabia, and subsequently, further studies to identify competent vectors and reservoir hosts for the establishment of control strategies are needed.

Investigation of the Sandfly Fauna of Central Arid Areas and Northern Humid Regions of Tunisia, with Morphological and Molecular Identification of the Recently Established Population of Phlebotomus (Larroussius) perfiliewi

Based on nucleotide sequences, we re-identified representative samples of Phlebotomus perfiliewi originating from two different biogeographical areas of Tunisia, whose populations had previously been identified based on morphological criteria. A partial region of the mitochondrial DNA cytochrome b gene was targeted, and sandfly species was determined by analogy with DNA sequences available in the GenBank database via a BLAST analysis, taking into account the query coverage and percentage identity. The recognized species presents the most substantial homology with the analyzed sequence. The results of the molecular identification showed complete agreement with the morphological identifications, and Phlebotomus perfiliewi is genetically variable.

Independent Circulation of Leishmania major and Leishmania tropica in Their Respective Sandfly Vectors for Transmission of Zoonotic and Chronic Cutaneous Leishmaniasis Co-Existing in a Mixed Focus of Central Tunisia

Zoonotic cutaneous leishmaniasis (ZCL) and chronic cutaneous leishmaniasis (CCL) are known to overlap in Central Tunisia. Sandflies were collected using sticky traps and CDC light-traps set in rodent burrows at the ecotones surrounding the village, in houses, and in animal shelters during July–October 2017, 2018, and 2019. A total of 17,175 sandflies were collected during the three sandfly seasons and identified morphologically to species level. Of a total of 18 sandfly species reported in Tunisia, 16 were identified in this mixed focus of ZCL and CCL. Except for the rocky mountainous areas, Phlebotomus papatasi was the most abundant sandfly species in all biotopes. In the mountainous areas, Phlebotomus sergenti is the most abundant sandfly species belonging to the genus Phlebotomus. Female sandflies were tested for the presence of Leishmania species by PCR. The overall infection prevalence of sandflies with Leishmania major and Leishmania tropica was 0.42% and 0.065%, respectively. The sequencing of PCR-amplified ITS1 products showed that L. major is the predominant species in all biotopes and transmitted mostly by P. papaptasi followed by Phlebotomus longicuspis and Sergentomyia species. Leishmania tropica was detected in Phlebotomus sergenti and in Phlebotomus longicuspis collected in bedrooms and in the ecotone of rocky mountainous areas. Our results provided strong evidence that the proximity of human settlements to biotopes of rodent reservoir hosts of L. major and of L. tropica resulted into the cocirculation of both Leishmania species leading to a mixed focus of ZCL and CCL. The epidemiology of leishmaniases in North Africa is highly complex by the high diversity of sandfly vectors and their associated Leishmania species, leading to a mixed form of cutaneous leishmaniasis. It is of major epidemiological importance to point to the risk of spillover from rural to urban areas leading to the anthroponization of cutaneous leishmaniasis. Therefore, efficient control to reduce the indoor abundance of sandfly vectors in order to reduce the incidence of leishmaniases is urgently needed.

A Review on Climate, Air Pollution, and Health in North Africa

PURPOSE OF REVIEW

The aim of this review is to summarize and provide clear insights into studies that evaluate the interaction between air pollution, climate, and health in North Africa.

RECENT FINDINGS

Few studies have estimated the effects of climate and air pollution on health in North Africa. Most of the studies highlighted the evidence of the link between climate and air pollution as driving factors and increased mortality and morbidity as health outcomes. Each North African country prioritized research on a specific health factor. It was observed that the health outcome from each driving factor depends on the studied area and data availability. The latter is a major challenge in the region. As such, more studies should be led in the future to cover more areas in North Africa and when more data are available. Data availability will help to explore the applicability of different tools and techniques new to the region. This review explores studies related to climate and air pollution, and their possible impacts on health in North Africa. On one hand, air quality studies have focused mainly on particulate matter exceedance levels and their long-term exposure impacts, namely, morbidity and mortality. The observed differences between the various studies are mainly due to the used exposure-response function, the studied population, background emissions, and natural emission from the Sahara Desert that characterize the region. On the other hand, climate studies have focused primarily on the impact of heat waves, vector-borne disease, and mental disorders. More than half of these studies have been on leishmaniasis disease. The review revealed unbalanced and insufficient research on health impacts from air pollution episodes and climate extremes across the region.

Identification of blood source preferences and Leishmania infection in sand flies (Diptera: Psychodidae) in north-eastern Algeria

Leishmaniases are among the most neglected vector-borne diseases, infecting humans as well various animal hosts with clinical outcomes varying from cutaneous disorders to visceral and life-threatening disease. In Algeria, canine leishmaniasis (CanL) caused by Leishmania infantum is endemic mainly throughout the northern regions of the country with the Mediterranean climate that favours the occurrence of Larroussius sand flies, the vectors of the parasite. This study conducted in Bougaa and Kherrata, two regions located in north-eastern Algeria and endemic for CanL, focuses on: i) composition of sand fly fauna, ii) screening of Leishmania parasites and iii) the blood sources of engorged females. Entomological surveys were conducted between June and September 2019 using CDC light-traps in rural areas of both regions. Sand fly specimens were morphologically identified, females were screened for Leishmania DNA using kDNA and ITS1 primers, blood meals in engorged females were identified by peptide mass mapping (PMM)-based MALDI-TOF mass spectrometry and confirmed by DNA sequencing analysis. Overall, 1940 specimens (844 males, 1096 females) were collected, all belonging to the subgenus Larroussius: Phlebotomus perniciosus, (94.64%), Ph. perfiliewi (4.74%) and Ph. longicuspis (0.62%). No Leishmania DNA was detected in the evaluated pools (n = 106) (1096 females). PMM-based MALDI-TOF MS successfully identified a source of blood in 92% (141/154) of engorged females (135 Ph. perniciosus and 6 Ph. perfiliewi). All blood meals were taken from domestic cattle (Bos taurus) except for one originating from a dog (Canis lupus familiaris) and one from sheep (Ovis aries). Sequencing of host cytochrome B gene confirmed these identifications but showed lower success rate of 58% (29/50), demonstrating the high effectivity of peptide mass mapping (PMM)-based MALDI-TOF mass spectrometry for routine identification of blood meals of varying degree of digestion. Our findings represent first record of cattle and dog blood in sand flies in Algeria and striking feeding preference of local sand fly population at domestic sites of studied regions for cattle which may play an important role in parasite transmission. Further studies are needed to better understand potential contribution of cattle to ecology of sand flies and epidemiology of leishmaniasis in north-eastern Algeria.

Diversity, Abundance and Leishmania infantum Infection Rate of Phlebotomine Sandflies in an Area with Low Incidence of Visceral Leishmaniasis in Northern Tunisia

We report the study of sandfly Leishmania infection in an area of low incidence of visceral leishmaniasis in Tunisia. Sandflies were collected monthly using CDC light-traps set in houses and animal shelters during May-November 2016 and 2017. All males were identified at the species level. A sample of 878 females including all gravid specimens was subjected to kDNA qPCR for Leishmania detection and parasite load estimation. Leishmania species were determined by ITS1 PCR sequencing, and species identification of infected sandflies was performed by DNA barcoding. Phlebotomus perfiliewi and P. perniciosus were the dominant species during the two-year period. However, comparison of their relative abundances showed that P. perniciosus was more abundant during peaks of 2017 with longer activity duration. Real-time kDNA PCR did not detect Leishmania infection in 2016, although it identified four positive specimens (0.7%) in 2017. All four infected specimens were identified as P. perniciosus. ITS1 PCR sequencing allowed L. infantum identification in one kDNA qPCR-positive specimen. This was a P. perniciosus gravid female with a high parasite load caught during the long-lasting peak of 2017. This work highlights the usefulness of multi-seasonal studies of sandfly dynamics and kDNA qPCR in screening Leishmania infection and determining L. infantum vectors in hypo-endemic foci of human leishmaniasis.

Geographic distribution of Meriones shawi and Psammomys obesus, the main reservoirs and Phlebotomus papatasi vector of zoonotic cutaneous leishmaniasis in Middle East and North Africa

Rodents play a significant role in the balance of a terrestrial ecosystem; they are considered prey for many predators like owls and snakes. However, they present a high risk to agriculture (damaging crops) and health. These rodents are the main reservoirs of some vector-borne diseases like leishmaniasis. Meriones shawi (MS) and Psammomys obesus (PO) are the primary Zoonotic cutaneous leishmaniasis (ZCL) reservoirs in the Middle East and North Africa (MENA). A review on the MS and PO at the MENA scale was explored. A database of about 1500 papers was used. 38 sites were investigated as foci for MS and 36 sites for PO, and 83 sites of Phlebotomus papatasi (Pp) in the studied region. An updated map at the regional scale and the trend of the reservoir distribution was carried out using a performing proper density analysis. In this paper, climatic conditions and habitat characteristics of these two reservoirs were reviewed. The association of rodent density with some climatic variables is another aspect explored in a case study from Tunisia in the period 2009–2015 using Pearson correlation. Lastly, the protection and control measures of the reservoir were analyzed. The high concentration of the MS, PO, and Pp can be used as an indicator to identify the high-risk area of leishmaniasis infection.

Risk Assessment of the Role of the Ecotones in the Transmission of Zoonotic Cutaneous Leishmaniasis in Central Tunisia

Zoonotic cutaneous leishmaniasis (ZCL), endemic in Central and Southern Tunisia, is caused by Leishmania major (Kinetoplastida: Trypanosomatidae), which is transmitted by the sand fly Phlebotomus papatasi. In Tunisia, the fat sand rat Psammomys obesus and the desert jird Meriones shawi are the principal reservoir hosts of L. major. The presence of the P. papatasi vector of the L. major etiologic agent of ZCL was assessed in the vicinity of villages in endemic areas of Central Tunisia. The study was performed from September through October 2019, a period corresponding to the main peak of activity of P. papatasi. Sand flies were collected from rodent burrows located at the ecotone level, which is the transition zone between the natural environment and human settlement. Sand flies were identified to species level and tested for the presence of L. major by PCR. Our entomological survey showed that P. papatasi is the most abundant sand fly species associated with rodent burrows, and this abundance is even higher in ecotones primarily occupied by P. obesus in comparison to ecotones occupied by M. shawi. Infections with Leishmania major were detected only in P. papatasi, with an overall minimum infection rate (MIR) of 2.64%. No significant difference was observed between the MIRs in ecotones of P. obesus and of M. shawi. Incidence of ZCL in the studied areas ranged from 200 to 700 cases per 100,000 inhabitants, with a mean incidence of 385.41 per 100,000. Higher ZCL incidence was identified in ecotones of M. shawi compared to ecotones of P. obesus. ZCL cases are positively correlated with the MIRs. Considering the short flight range of P. papatasi, increases in its densities associated with burrows of P. obesus or M. shawi at the ecotone level expand the overlap of infected vectors with communities and subsequently increase ZCL incidence. Therefore, control measures should target P. papatasi populations at the ecotones.

Enhanced attraction of sand fly vectors of Leishmania infantum to dogs infected with zoonotic visceral leishmaniasis

BACKGROUND

The sand fly Phlebotomus perniciosus is the main vector of Leishmania infantum, etiological agent of zoonotic visceral leishmaniasis in the Western Mediterranean basin. Dogs are the main reservoir host of this disease. The main objective of this study was to determine, under both laboratory and field conditions, if dogs infected with L. infantum, were more attractive to female P. perniciosus than uninfected dogs.

METHODOLOGY/PRINCIPAL FINDINGS

We carried out a series of host choice experiments and found that infected dogs were significantly more attractive to P. perniciosus than uninfected dogs in the laboratory as well as in the field. Significantly more P. perniciosus fed on infected dogs than on uninfected dogs. However, the fecundity of P. perniciosus fed on infected dogs was adversely impacted compared to uninfected dogs by lowering the number of laid eggs. Phlebotomus perfiliewi, the second most abundant sand fly species in the field site and a competent vector of L. infantum had similar trends of attractivity as P. perniciosus toward infected dogs under field conditions.

CONCLUSIONS

The results strongly suggest that L. infantum causes physiological changes in the reservoir host which lead to the host becoming more attractive to both male and female P. perniciosus. These changes are likely to improve the chance of successful transmission because of increased contact with infected hosts and therefore, infected dogs should be particularly targeted in the control of zoonotic visceral leishmaniasis in North Africa.

The Impact of Illegal Waste Sites on the Transmission of Zoonotic Cutaneous Leishmaniasis in Central Tunisia

Illegal waste disposal represents a risk health factor for vector-borne diseases by providing shelter for rodents and their ectoparasites. The presence of the Phlebotomus papatasi vector of Leishmania major, an etiologic agent of zoonotic cutaneous leishmaniasis (ZCL), was assessed at illegal waste sites located at the vicinity of villages in endemic areas of Central Tunisia. The study was performed over a two-year period over three nights from July to September 2017, and over three nights in September 2018. Household waste is deposited illegally forming dumpsites at the vicinity of each village and contains several rodent burrows of Psammomys obesus, the main reservoir host of L. major. Sandflies were collected from rodent burrows in the natural environment and in dumpsites using sticky traps and were identified at species level. Female sandflies were tested for the presence of L. major by PCR. Our entomological survey showed that Phlebotomus papatasi is the most abundant sandfly species associated with rodent burrows in these waste sites. The densities of P. papatasi in dumpsites are significantly higher compared to the natural environment. The minimum infection rate of P. papatasi with L. major in these illegal waste sites is not significantly different compared to the natural environment. Considering the short flight range of P. papatasi, increases in its densities, associated with burrows of P. obesus in illegal waste sites located at the edge of villages, expands the overlap of infected ZCL vectors with communities. Thus, illegal waste sites pose a high risk of spreading ZCL to neighboring home ranges. Waste management is an environmentally friendly method of controlling sandfly populations and should be included in an integrated management program for controlling ZCL in endemic countries.

Seasonal Distribution of Phlebotomus papatasi, Vector of Zoonotic Cutaneous Leishmaniasis

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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.

Nonlinearities in transmission dynamics and efficient management of vector-borne pathogens

Integrated Pest Management (IPM) is an approach to minimizing economic and environmental harm caused by pests, and Integrated Vector Management (IVM) uses similar methods to minimize pathogen transmission by vectors. The risk of acquiring a vector-borne infection is often quantified using the density of infected vectors. The relationship between vector numbers and risk of human infection is more or less linear when both vector numbers and pathogen prevalence in vectors are low, but the relationship is nonlinear when vector density and/or infection prevalence are high. Therefore, the density of infected vectors often does not accurately predict risk of human exposure to pathogens, and traditional estimates of the percent control often overestimate the level of protection from infection resulting from management programs. We suggest a modified estimator, percent protection, which more accurately quantifies protection against human infection resulting from a management intervention. Cost-effectiveness of a management program is critical to protection of both public health and the environment, because the more efficiently available resources and funding are used, the fewer people get sick, and well-targeted efficient management programs minimize the need for poorly targeted, expensive environmental interventions (e.g., broadscale pesticide applications) that tend to damage nontarget organisms and natural systems. Design of an efficient, cost-effective IVM program requires knowledge of the cost-effectiveness functions (the effectiveness of control methods at lowering vector bites and/or infection prevalence with different levels of application) of the various control methods to be applied. Alternative programs can be designed that optimize percent protection by integrating different control methods at different levels of investment, and environmental effects of these alternatives can be compared, allowing environmental considerations to be included explicitly in the decision process. IPM, IVM, and Adaptive Management share the characteristic that management decisions must be made with incomplete knowledge of the functioning of natural systems or the efficacies of interventions. IVM surveillance programs that assess the effects of individual control methods and of combinations of control methods on the numbers of vector bites and on infection prevalence in vectors can increase knowledge of pathogen transmission dynamics and provide information to improve program effectiveness in subsequent applications.

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.

Molecular detection of Leishmania infantum DNA and host blood meal identification in Phlebotomus in a hypoendemic focus of human leishmaniasis in northern Algeria

BACKGROUND

Leishmania parasites are transmitted by female phlebotomine sand flies that maintain the enzootic cycle by circulating between sylvatic and domestic mammals. Humans are part of this cycle as accidental hosts due to the vector's search for a source of blood. In Algeria, Human Leishmaniases (HL) are endemic and represent a serious public health problem because of their high annual incidence and their spread across the country. The aim of this study is to identify sand fly species fauna (vectors of Leishmania), determine their infection rate and identify their feeding preferences using molecular tools in a hypoendemic focus of HL located in the province of Tipaza, northern Algeria.

METHODOLOGY/PRINCIPAL FINDINGS

An entomological survey using CDC light traps was conducted between July and October of 2015 in four HL affected peri-urban locations in the province of Tipaza, northern Algeria. Sand flies were identified using the morphological criteria of the genitalia for the males and spermathecae for the females. Leishmania DNA was detected in pooled female sand flies (N = 81 pools with 8-10 specimens per pool) using quantitative real-time polymerase chain reaction (qPCR) targeting two different genes: kDNA-PCR and 18S rRNA. To identify their blood meal sources, blood-fed female sand flies were analyzed by PCR-sequencing targeting the vertebrate cytochrome c oxidase I (COI) gene. A total of 4,045 sand flies were caught, of which 3,727 specimens were morphologically identified. Seven species were recorded: P. (L.) perniciosus (50.28%), P. (L.) perfiliewi (26.13%), P. (L.) longicuspis (21.92%), Sergentomyia (S.) minuta (0.85%), P. (P.) papatasi (0.42%), P. (L.) langeroni (0.32%) and P. (L.) ariasi (0.05%). Afterwards, 740 female specimens were randomly selected and divided into 81 pools and were then screened to investigate the presence of Leishmania spp. L. infantum DNA was detected in three pools, corresponding to three sand fly specimens (one each). The infection rate was 0.33% (2/600) for P. (L.) perniciosus and 2.56% (1/39) for P. (L.) perfiliewi. Analysis of the blood feeding sources (N = 88 specimens) revealed that sand flies belonging to Larroussius subgenera, mainly (71.5%) feed on small ruminants. Human blood is the second feeding source (17%), eight specimens (9%) were found to feed on equines and no domestic reservoir (dog) blood was found.

CONCLUSIONS/SIGNIFICANCE

The presence of human leishmaniasis cases, the high abundance of Phlebotomus (Larroussius) species which are proven or suspected vectors of L. infantum, and the detection of L. infantum DNA from its natural vectors (P. (L.) perniciosus, P. (L.) perfiliewi), in addition to the blood-feeding of positive females for L. infantum on humans blood, prove that the major elements of the epidemiological transmission cycle of L. infantum are present and indicate risk factors for an outbreak of the disease in the province of Tipaza.

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.

Molecular identification of Leishmania infection in the most relevant sand fly species and in patient skin samples from a cutaneous leishmaniasis focus, in Morocco

BACKGROUND

Cutaneous leishmaniasis (CL) is an infectious disease caused by various species of Leishmania and transmitted by several species of sand flies. CL is among the most neglected tropical diseases, and it has represented a major health threat over the past 20 years in Morocco. The main objectives of this study were to identify relevant sand fly species and detect Leishmania infection in the most prevalent species and patient skin samples in Taza, a focus of CL in North-eastern Morocco.

METHODOLOGY AND FINDING

A total of 3672 sand flies were collected by CDC miniature light traps. Morphological identification permitted the identification of 13 species, namely 10 Phlebotomus species and 3 Sergentomyia species. P. longicuspis was the most abundant species, comprising 64.08% of the total collected sand flies, followed by P. sergenti (20.1%) and P. perniciosus (8.45%). Using nested-kDNA PCR, seven pools of P. sergenti were positive to Leishmania tropica DNA, whereas 23 pools of P. longicuspis and 4 pools of P. perniciosus tested positive for Leishmania infantum DNA. The rates of P. longicuspis and P. perniciosus Leishmania infection were 2.51% (23/915) and 7.27% (4/55), respectively, whereas the infection prevalence of P. sergenti was 3.24%. We also extracted DNA from lesion smears of 12 patients suspected of CL, among them nine patients were positive with enzymatic digestion of ITS1 by HaeIII revealing two profiles. The most abundant profile, present in eight patients, was identical to L. infantum, whereas L. tropica was found in one patient. The results of RFLP were confirmed by sequencing of the ITS1 DNA region.

CONCLUSION

This is the first molecular detection of L. tropica and L. infantum in P. sergenti and P. longicuspis, respectively, in this CL focus. Infection of P. perniciosus by L. infantum was identified for the first time in Morocco. This study also underlined the predominance of L. infantum and its vector in this region, in which L. tropica has been considered the causative agent of CL for more than 20 years.

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.

Risk factors for mortality of children with zoonotic visceral leishmaniasis in Central Tunisia

BACKGROUND

Zoonotic visceral leishmaniasis (ZVL) caused by Leishmania infantum is endemic with an epidemiological profile of a paediatric disease in Tunisia. In the context of a high fatality rate, identifying risk factors for in-hospital mortality in children treated for ZVL is of major epidemiological importance.

DESIGN

A retrospective (case-control) study included 230 immuno-competent children diagnosed and confirmed with primary ZVL in the paediatric department of the University Hospital of Kairouan between 2004 and 2014. Forty-seven per cent (47%) were children under 18 months of age, and with a male ⁄ female ratio of 1.01:1.

RESULTS

The overall case-fatality was 6% (n = 14). The risk factors for in-hospital death identified by a multivariate analysis were: bleeding at admission (OR = 25.5, 95% CI: 2.26-287.4; p = 0.009), white cell count less than 4000/mm3 (OR = 5.66, 95% CI: 1.16-27.6; p = 0.032), cytolysis (OR = 28.13, 95% CI: 4.55-173.6; p < 0.001), and delay between onset of symptoms and admission ≥ 15 days (OR = 11, 95% CI: 1.68-72; p = 0.012).

CONCLUSION

The results strongly suggest that paediatric patients admitted 15 days after onset of symptoms, with bleeding, white cell counts below 4,000/mm3, and cytolysis at admission should be considered severe cases and subsequently, they are at high risk of mortality. A better understanding of factors associated with death of children from ZVL may contribute to decrease mortality.

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.

Cutaneous leishmaniasis in northwestern Saudi Arabia: identification of sand fly fauna and parasites

BACKGROUND

Cutaneous leishmaniasis (CL) is a vector-borne disease transmitted by the bite of an infected sand fly. This disease is highly prevalent in Saudi Arabia where Leishmania major and L. tropica are the etiological agents. In the region of Hail, northwestern of Saudi Arabia, the incidence is about 183 cases/year. However, the epidemiology of the disease in this area is not well understood. Thus, an epidemiological survey was conducted in 2015-2016 to identify the circulating parasite and the sand fly fauna in the region of Hail. Skin lesion scrapings were collected from suspected patients with CL.

METHODS

The diagnosis was made by microscopic examination of Giemsa-stained smear and PCR. The parasite was identified by PCR and sequencing of the single copy putative translation initiation factor alpha subunit gene. Sand fly specimens were collected and identified morphologically. Total DNA was extracted from the abdomen of female specimens and Leishmania DNA was detected by PCR.

RESULTS

Among the 57 examined patients, 37 were positive for CL. The identification of the parasite has revealed the single species Leishmania major. The 384 sand flies were collected belonged to two genera (Phlebotomus and Sergentomyia), six sub-genera and six species. Phlebotomus papatasi, Ph. kazeruni and Sergentomyia clydei were the dominant species. Leishmania DNA was detected in two females of Ph. papatasi two of Ph. kazeruni and one specimen of Sergentomyia clydei.

CONCLUSIONS

Leishmania major is confirmed to be the etiological agent of cutaneous leishmaniasis in northwestern Saudi Arabia. The molecular detection of Leishmania DNA in Ph. papatasi and Ph. kazeruni supports the potential role of these two species in the transmission of Leishmania. Further epidemiological studies are needed to prove their role and to evaluate the burden of CL in the study region.

First Report on Natural Infection of Phlebotomus sergenti with Leishmania tropica in a Classical Focus of Leishmania major in Tunisia

In Tunisia, chronic cutaneous leishmaniasis due to Leishmania tropica is an important health problem. Its spreading has not been fully elucidated. Information on sandfly vectors, as well as their associated Leishmania species, is of paramount importance since vector dispersion is one of the major factors responsible for pathogen dissemination. Ninety-seven unfed females belonging to the genera Sergentomyia and Phlebotomus were collected between June and August 2015 using sticky paper traps. Polymerase chain reaction-restriction fragment length polymorphism analysis of the internal transcribed spacer 1and sequencing were used for Leishmania detection and identification. In total, 650 sandflies were captured and identified (380 males and 270 females). Ninety-seven unfed females were tested for the presence of Leishmania parasite DNA. Six Phlebotomus sergenti were found positive for L. tropica. This novel finding enhances the understanding of the cycle extension of L. tropica outside its original focus of Tataouine.

An integrated overview of the midgut bacterial flora composition of Phlebotomus perniciosus, a vector of zoonotic visceral leishmaniasis in the Western Mediterranean Basin

Background

The Leishmania developmental life cycle within its sand fly vector occurs exclusively in the lumen of the insect’s digestive tract in the presence of symbiotic bacteria. The composition of the gut microbiota and the factors that influence its composition are currently poorly understood. A set of factors, including the host and its environment, may influence this composition. It has been demonstrated that the insect gut microbiota influences the development of several human pathogens, such as Plasmodium falciparum. For sand flies and Leishmania, understanding the interactions between the parasite and the microbial environment of the vector midgut can provide new tools to control Leishmania transmission.

Methodology/Principal findings

The midguts of female Phlebotomus perniciosus from laboratory colonies or from the field were collected during the months of July, September and October 2011 and dissected. The midguts were analyzed by culture-dependent and culture-independent methods. A total of 441 and 115 cultivable isolates were assigned to 30 and 11 phylotypes from field-collected and colonized P. perniciosus, respectively. Analysis of monthly variations in microbiota composition shows a species diversity decline in October, which is to the end of the Leishmania infantum transmission period. In parallel, a compilation and a meta-analysis of all available data concerning the microbiota of two Psychodidae genera, namely Phlebotomus and Lutzomyia, was performed and compared to P. perniciosus, data obtained herein. This integrated analysis did not reveal any substantial divergences between Old and New world sand flies with regards to the midgut bacterial phyla and genera diversity. But clearly, most bacterial species (>76%) are sparsely distributed between Phlebotominae species.

Conclusion/Significance

Our results pinpoint the need for a more exhaustive understanding of the bacterial richness and abundance at the species level in Phlebotominae sand flies in order to capture the role of midgut bacteria during Leishmania development and transmission. The occurrence of Bacillus subtilis in P. perniciosus and at least two other sand fly species studied so far suggests that this bacterial species is a potential candidate for paratransgenic or biolological approaches for the control of sand fly populations in order to prevent Leishmania transmission.

The use of conventional microbiological methods gave us the opportunity to investigate the richness of symbiotic bacteria that inhabit the gut of P. perniciosus during its main period of activity. Our results were subsequently analyzed in the framework of what has been done on sand flies microbiota in order to validate our results and to address the question of the definition of the core bacterial microbiota of sand flies. A meta-analysis on the respective gut microbiota of Old and New World sand flies shows that the majority of bacterial species is observed only in one host whereas less than 8% are shared by more than two hosts. Our results pinpoint the need for a more exhaustive understanding of the microbiota composition and dynamic in phlebotominae, with the aim to implement new biological approaches for the control of sand fly populations in order to prevent Leishmania transmission.