RESUMO
To examine the genetic diversity of Leishmania major, 100 Giemsa-stained positive slides were collected from endemic foci of Iran (Northeast, Central, and Southwest provinces) over two consecutive years during 2019-2021. The Leishmania ITS-rDNA gene was amplified and Leishmania sp. was recognized by PCR-RFLP and sequencing. In addition, 178 registered ITS-rDNA sequences from other geographical regions of Iran were retrieved from GenBank, including different host species (human, sandfly and rodent). A total of 40 new haplotypes were discovered using the ITS-rDNA sequence analysis. IR29 (20.6%) and IR34 (61%) were the two most common haplotypes, represented by a star-like feature in the overall population. Analysis of the molecular variance test revealed low genetic diversity of L. major in human cases (Haplotype diversity; 0.341), rodent (Hd; 0.387) and sandfly (Hd; 0.390) sequences. The lowest genetic diversity of L. major was observed in Southwest/Southeast Iran (Hd: 0.104-0.286). The statistically Fst value indicated that L. major is not genetically differentiated between geographic regions of Iran, except for the Northeast-Southwest (Fst: 0.29055) and Central-Southwest (Fst: 0.30294) population pairs. The current study as the first investigation discloses new perspectives for further evaluation in the identification local transmission paradigms and initiating effective prevention strategies.
Assuntos
Leishmania major , Leishmaniose Cutânea , Phlebotomus , Psychodidae , Humanos , Animais , Leishmania major/genética , Leishmaniose Cutânea/epidemiologia , Leishmaniose Cutânea/genética , Heterogeneidade Genética , Irã (Geográfico)/epidemiologia , Psychodidae/genética , Phlebotomus/genética , DNA Ribossômico , Roedores/genéticaRESUMO
Leishmania aethiopica is a zoonotic Old World parasite transmitted by Phlebotomine sand flies and causing cutaneous leishmaniasis in Ethiopia and Kenya. Despite a range of clinical manifestations and a high prevalence of treatment failure, L. aethiopica is one of the most neglected species of the Leishmania genus in terms of scientific attention. Here, we explored the genome diversity of L. aethiopica by analyzing the genomes of twenty isolates from Ethiopia. Phylogenomic analyses identified two strains as interspecific hybrids involving L. aethiopica as one parent and L. donovani and L. tropica respectively as the other parent. High levels of genome-wide heterozygosity suggest that these two hybrids are equivalent to F1 progeny that propagated mitotically since the initial hybridization event. Analyses of allelic read depths further revealed that the L. aethiopica - L. tropica hybrid was diploid and the L. aethiopica - L. donovani hybrid was triploid, as has been described for other interspecific Leishmania hybrids. When focusing on L. aethiopica, we show that this species is genetically highly diverse and consists of both asexually evolving strains and groups of recombining parasites. A remarkable observation is that some L. aethiopica strains showed an extensive loss of heterozygosity across large regions of the nuclear genome, which likely arose from gene conversion/mitotic recombination. Hence, our prospection of L. aethiopica genomics revealed new insights into the genomic consequences of both meiotic and mitotic recombination in Leishmania.
Assuntos
Leishmania , Leishmaniose Cutânea , Psychodidae , Animais , Leishmania/genética , Leishmaniose Cutânea/parasitologia , Psychodidae/parasitologia , Filogenia , Hibridização de Ácido NucleicoRESUMO
Visceral leishmaniasis (VL) is a vector-borne protozoan disease, which can be fatal if left untreated. Synthetic chemical insecticides are very effective tools for controlling of insect vectors, including the sand fly Phlebotomus argentipes, the vector of VL in the Indian subcontinent. However, repeated use of the same insecticide with increasing doses potentially can create high selection pressure and lead to tolerance and resistance development. The objective of this study was to determine the lethal concentrations and assess levels of susceptibility, diagnostic doses and times to death of laboratory-reared P. argentipes to five insecticides that are used worldwide to control vectors. Using the Center for Disease Control and Prevention (CDC) bottle bioassay, 20-30 sand flies were exposed in insecticide- coated 500-ml glass bottles. Flies were then observed for 24 hours and mortality was recorded. Dose-response survival curves were generated for each insecticide using QCal software and lethal concentrations causing 50%, 90% and 95% mortality were determined. A bioassay was also conducted to determine diagnostic doses and diagnostic times by exposing 20-30 flies in each bottle containing set concentrations of insecticide. Mortality was recorded at 10-minute intervals for 120 minutes to generate the survival curve. Phlebotomus argentipes are highly susceptible to alpha-cypermethrin, followed by deltamethrin, malathion, chlorpyrifos, and least susceptible to DDT. Also, the lowest diagnostic doses and diagnostic times were established for alpha-cypermethrin (3µg/ml for 40 minutes) to kill 100% of the flies. The susceptibility data, diagnostic doses and diagnostic times presented here will be useful as baseline reference points for future studies to assess insecticide susceptibility and resistance monitoring of field caught sand flies and to assist in surveillance as VL elimination is achieved in the region.
Assuntos
Inseticidas , Leishmaniose Visceral , Phlebotomus , Psychodidae , Animais , Estados Unidos , Inseticidas/farmacologia , Phlebotomus/fisiologia , Leishmaniose Visceral/prevenção & controle , Resistência a Inseticidas , Índia , Bioensaio , Centers for Disease Control and Prevention, U.S.RESUMO
BACKGROUND: The transmission dynamics of leishmaniasis are complex. There is also a lack of information about the ecological relationships between the vector/host/parasite at a more local and specific level. The Andean region concentrates more than 50% of Colombia's cutaneous leishmaniasis (CL) cases. The study of the ecological interactions of sand flies through the identification of blood sources has provided information on the female's opportunistic behavior, feeding on various hosts. Therefore, this study aimed to determine sand flies' ecological interactions with Leishmania parasites and their blood sources in an endemic area of CL. RESULTS: A total of 4,621 sand flies were collected, comprising 20 species, in which the most abundant were Nyssomyia yuilli yuilli (55.4%), Psychodopygus ayrozai (14.5%) and Ps. panamensis (13.4%). Sequences of 12S gene fragment were analyzed using the BLASTn search tool. Blood-meal source identification was successfully performed for 47 sand flies, detecting seven vertebrate species, human and armadillo being the most frequent. Leishmania DNA was amplified in four female pools, constituted by Ny. yuilli yuilli and Ps. ayrozai, and the identification through RFLP detected Leishmania (Viannia) panamensis in the positive pools. CONCLUSIONS: The interactions between the sand fly species, local mammalian fauna and the Leishmania parasite in this active focus of CL, provide evidence of the potential role of two different species in the maintenance of the parasite transmission, important information for the understanding of the ecoepidemiology and transmission dynamics of the disease in Andean endemic areas. However its necessary further evaluations of the vector and host competence in the transmission and maintenance of Leishmania spp, in these complex and diverse areas.
Assuntos
Leishmania guyanensis , Leishmania , Leishmaniose Cutânea , Psychodidae , Animais , Feminino , Humanos , Psychodidae/parasitologia , Colômbia , Insetos Vetores/parasitologia , Leishmaniose Cutânea/epidemiologia , Leishmania/genética , MamíferosRESUMO
Phlebotomine sand flies of the genus Sergentomyia are considered to be of minor importance as vectors of Leishmania parasites pathogenic to humans, but are known to transmit lizard parasites of the subgenus Sauroleishmania, including L. (S.) adleri. However, knowledge on the geographic distribution of Sauroleishmania spp. and the infection rates in the vectors is very limited. Therefore, our study aimed (1) to further elucidate the distribution and prevalence of Sauroleishmania spp. in their respective vectors and (2) to assess the potential risk for occasional transmission of Leishmania parasites to international military personnel deployed in camps in Mali and Niger. A total of 1,482 wild-caught sand flies (Sergentomyia spp. and closely related Grassomyia spp.) were screened by real-time PCR for the presence of Leishmania DNA. Thirty-two sand fly pools were tested positive, with six from Mali and 26 from Niger. The DNA of four representative isolates was sequenced. The resulting sequences revealed a homology to L. adleri, which leads to the first report of this species from Mali and Niger to the best of our knowledge. The results suggest that Sergentomyia (Sintonius) clydei might be the natural sand fly vector, while Grassomyia spp. appear to be refractory. No Leishmania sp. pathogenic to humans was detected in these sand flies.
Assuntos
Leishmania , Phlebotomus , Psychodidae , Humanos , Animais , Leishmania/genética , Psychodidae/parasitologia , Mali , Níger , Insetos Vetores/parasitologia , Phlebotomus/parasitologia , DNA/genéticaRESUMO
New World sandflies are vectors of leishmaniasis, bartonellosis, and some arboviruses. A classification based on 88 morphological characters was proposed 27 years ago when the New World phlebotomines were organized into two tribes Hertigiini and Phlebotomini. The latter was structured into four subtribes (Brumptomyiina, Sergentomyiina, Lutzomyiina, and Psychodopygina) and 20 genera. The subtribe Psychodopygina, including most of the American vectors of tegumentary Leishmania comprises seven genera from which no molecular work has been produced to support this classification. Here, we carried out a molecular phylogeny based on combined sequences (1,334 bp) of two genes: partial 28S rDNA and mtDNA cytochrome b from 47 taxa belonging to the Psychodopygina. The Bayesian phylogenetic reconstruction agreed with the classification based on morphological characters, supporting the monophyly of the genera Psychodopygus and Psathyromyia, whereas Nyssomyia and Trichophoromyia seemed to be paraphyletic. The paraphylies of the two latter groups were exclusively caused by the doubtful position of the species Ny. richardwardi. Our molecular analysis provides additional support to adopt the morphologic classification of Psychodopygina.
Title: La phylogénie moléculaire des Psychodopygina (Diptera, Psychodidae) soutient la systématique morphologique de ce groupe de vecteurs de leishmaniose cutanée du Nouveau Monde. Abstract: Les phlébotomes du nouveau monde sont des vecteurs de leishmaniose, de bartonellose et de certains arbovirus. Une classification basée sur 88 caractères morphologiques a été proposée il y a 27 ans lorsque les phlébotomes du nouveau monde ont été organisés en deux tribus Hertigiini et Phlebotomini. Cette dernière était structurée en quatre sous-tribus (Brumptomyiina, Sergentomyiina, Lutzomyiina et Psychodopygina) et 20 genres. La sous-tribu des Psychodopygina, qui inclut la plupart des vecteurs américains de la leishmaniose cutanée, comprend sept genres mais aucun travail moléculaire n'a été produit pour soutenir cette classification. Dans cet article, nous avons réalisé une phylogénie moléculaire basée sur des séquences combinées (1334 pb) de deux gènes : ADNr 28S partiel et cytochrome b (ADNmt) chez 47 taxons appartenant aux Psychodopygina. La reconstruction phylogénique bayésienne est en accord avec la classification basée sur les caractères morphologiques, soutenant la monophylie des genres Psychodopygus et Psathyromyia, alors que Nyssomyia et Trichophoromyia semblent être paraphylétiques. Les paraphylies des deux derniers groupes sont exclusivement causées par la position douteuse de la seule espèce Ny. richardwardi. Notre analyse moléculaire fournit une raison supplémentaire pour adopter la classification morphologique des Psychodopygina.
Assuntos
Leishmania , Leishmaniose Cutânea , Psychodidae , Animais , Filogenia , Teorema de Bayes , Leishmania/genéticaRESUMO
Sand flies are the exclusive vectors of leishmaniasis. This group of parasitic diseases is a serious public health problem in Morocco. The aim of this study was to investigate the sand fly fauna, mainly the species composition, biodiversity, and seasonal activity of sand flies in El Hajeb in central Morocco. A total of six stations (Aït Naaman, Aït Rbaa, Aït Brahim, Ain Taoujdate, Sidi Mbarek, and Aït Oufella) were studied, five of which had recently recorded cases of leishmaniasis. Sand fly bimonthly captures were carried out using a sticky paper trap in different biotopes from March to December 2019. A total of 14590 adult sand flies were collected. The activity of the sand fly started in April and declined in November. The periods of high abundance were July, September, and November. Morphological identification of sand flies shows the presence of twelve species: Phlebotomus papatasi, P. longicuspis, P. perniciosus, P. sergenti, P. bergeroti, P. alexandri, P. dreyfussi, P. ariasi, Sergentomyia fallax, S. minuta, S. schwetzi, and S. antennata. The analysis showed that species belonging to the genus Phlebotomus were the most dominant (93.3%) and the risk periods were spread during the summer and autumn seasons. The present study provides for the first time information on the species of sand flies in El Hajeb. It, therefore, provides decision makers with an important tool to conduct vector control actions during peak periods in order to limit the transmission of leishmaniasis. A preprint was made available by the research square in the following link: "https://assets.researchsquare.com/files/rs-1409330/v1/dfef7013-0327-4a54-897f-214924a2d950.pdf?c=1646838874."
Assuntos
Leishmaniose Cutânea , Leishmaniose Visceral , Leishmaniose , Phlebotomus , Psychodidae , Animais , Adulto , Humanos , Leishmaniose Visceral/epidemiologia , Leishmaniose Visceral/parasitologia , Marrocos , Phlebotomus/parasitologia , Leishmaniose/parasitologia , Leishmaniose Cutânea/epidemiologia , Leishmaniose Cutânea/parasitologiaRESUMO
Attachment to a substrate to maintain position in a specific ecological niche is a common strategy across biology, especially for eukaryotic parasites. During development in the sand fly vector, the eukaryotic parasite Leishmania adheres to the stomodeal valve, as the specialised haptomonad form. Dissection of haptomonad adhesion is a critical step for understanding the complete life cycle of Leishmania. Nevertheless, haptomonad studies are limited, as this is a technically challenging life cycle form to investigate. Here, we have combined three-dimensional electron microscopy approaches, including serial block face scanning electron microscopy (SBFSEM) and serial tomography to dissect the organisation and architecture of haptomonads in the sand fly. We showed that the attachment plaque contains distinct structural elements. Using time-lapse light microscopy of in vitro haptomonad-like cells, we identified five stages of haptomonad-like cell differentiation, and showed that calcium is necessary for Leishmania adhesion to the surface in vitro. This study provides the structural and regulatory foundations of Leishmania adhesion, which are critical for a holistic understanding of the Leishmania life cycle.
Assuntos
Leishmania , Psychodidae , Animais , Microscopia EletrônicaRESUMO
Cutaneous leishmaniasis caused by Leishmania major or L. tropica and visceral leishmaniasis caused by L. infantum have been reported in Israel. We collected Phlebotomus spp. sand flies in the Negev desert of southern Israel to identify circulating Leishmania spp. Of 22,636 trapped sand flies, 80% were P. alexandri. We sequenced Leishmania-specific internal transcribed spacer 1 fragments and K26 genes. Of 5,019 Phlebotomus female sand flies, 2.5% were Leishmania DNA-positive; 92% of infections were L. donovani. Phylogenetic analyses showed separate clustering of L. donovani and L. infantum. P. alexandri flies positive for L. donovani harbored blood meals from European hares. Leishmania DNA isolated from a patient with cutaneous leishmaniasis who lived in the survey area was identical to L. donovani from P. alexandri flies. We report circulation of L. donovani, a cause of visceral leishmaniasis, in southern Israel. Prompt diagnosis and Leishmania spp. identification are critical to prevent leishmaniasis progression.
Assuntos
Lebres , Leishmania donovani , Leishmaniose Cutânea , Leishmaniose Visceral , Phlebotomus , Psychodidae , Animais , Humanos , Feminino , Leishmania donovani/genética , Leishmaniose Visceral/diagnóstico , Filogenia , Israel/epidemiologia , DNARESUMO
Phlebotomine sand flies are of global significance as important vectors of human disease, transmitting bacterial, viral, and protozoan pathogens, including the kinetoplastid parasites of the genus Leishmania, the causative agents of devastating diseases collectively termed leishmaniasis. More than 40 pathogenic Leishmania species are transmitted to humans by approximately 35 sand fly species in 98 countries with hundreds of millions of people at risk around the world. No approved efficacious vaccine exists for leishmaniasis and available therapeutic drugs are either toxic and/or expensive, or the parasites are becoming resistant to the more recently developed drugs. Therefore, sand fly and/or reservoir control are currently the most effective strategies to break transmission. To better understand the biology of sand flies, including the mechanisms involved in their vectorial capacity, insecticide resistance, and population structures we sequenced the genomes of two geographically widespread and important sand fly vector species: Phlebotomus papatasi, a vector of Leishmania parasites that cause cutaneous leishmaniasis, (distributed in Europe, the Middle East and North Africa) and Lutzomyia longipalpis, a vector of Leishmania parasites that cause visceral leishmaniasis (distributed across Central and South America). We categorized and curated genes involved in processes important to their roles as disease vectors, including chemosensation, blood feeding, circadian rhythm, immunity, and detoxification, as well as mobile genetic elements. We also defined gene orthology and observed micro-synteny among the genomes. Finally, we present the genetic diversity and population structure of these species in their respective geographical areas. These genomes will be a foundation on which to base future efforts to prevent vector-borne transmission of Leishmania parasites.
Assuntos
Leishmania , Leishmaniose Cutânea , Phlebotomus , Psychodidae , Animais , Humanos , Phlebotomus/parasitologia , Psychodidae/parasitologia , Leishmania/genética , GenômicaRESUMO
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.
Assuntos
Doenças do Cão , Leishmania infantum , Leishmaniose Visceral , Leishmaniose , Phlebotomus , Psychodidae , Vírus da Febre do Flebótomo Napolitano , Feminino , Chlorocebus aethiops , Cães , Animais , Leishmaniose Visceral/epidemiologia , Leishmaniose Visceral/veterinária , Vírus da Febre do Flebótomo Napolitano/genética , Leishmania infantum/genética , Tunísia/epidemiologia , Células Vero , Phlebotomus/genética , DNA , Doenças do Cão/epidemiologiaRESUMO
Many virological studies have tested the persistence of enveloped RNA viruses in various environmental and laboratory conditions and shown their short-term persistence. In this article, we analyzed Toscana virus (TOSV) infectivity, a pathogenic sandfly-borne phlebovirus, in two different conditions: in the sugar meal and blood meal of sand flies. Our results showed that TOSV RNA was detectable up to 15 days in sugar solution at 26 °C and up to 6 h in blood at 37 °C. Moreover, TOSV remains infective for 7 days in sugar solution and for minimum 6 h in rabbit blood. TOSV has shown persistent infectivity/viability under different conditions, which may have important epidemiological consequences. These results strengthen new hypotheses about the TOSV natural cycle, such as the possibility of horizontal transmission between sand flies through infected sugar meal.
Assuntos
Phlebovirus , Psychodidae , Vírus da Febre do Flebótomo Napolitano , Animais , Coelhos , Açúcares , Phlebovirus/genética , Refeições , Anticorpos AntiviraisRESUMO
Phlebotomine sand flies are dipterans of relevance due to their role as vectors of several pathogens worldwide. Bacteria in the gut of sand flies possibly affect their vectorial capacity and competence to transmit parasites. A retrospective study was performed in sand fly specimens that had previously been collected in four localities of the state of Chiapas during the period 2009-2011 to detect Wolbachia and Bartonella and their possible coinfection with Leishmania. For the molecular detection of bacteria, we used primers and conditions that had previously been reported. A total of 531 sand fly specimens of 10 species were analyzed. Four Wolbachia strains were detected in five sand fly species, showing a prevalence of 8.6%. All the Wolbachia strains had previously been reported in other taxa. In one sand fly species, we also detected a new lineage of Bartonella evidenced by a phylogenetic analysis. No sand fly specimens showed coinfections of these bacteria and Leishmania. The bacteria found in the phlebotomine sand flies are possibly transmitted by plant-mediated horizontal transmission and during blood meal feeding.
Assuntos
Bartonella , Leishmania , Microbiota , Phlebotomus , Psychodidae , Wolbachia , Animais , Psychodidae/parasitologia , Wolbachia/genética , Bartonella/genética , México , Filogenia , Estudos Retrospectivos , BactériasRESUMO
The community structure of sand flies indicates the level of adaptation of vector species in a region, and in the context of vector management and control, this information allows for identifying the potential risks of pathogen transmission. This study aimed to analyze sand fly diversity and spatial-temporal distribution in an endemic area of cutaneous leishmaniasis. The study was carried out in the Carrizales hamlet (Caldas), between September 2019 and October 2021. The monthly distribution of sand fly species was evaluated through collections with CDC traps. Shannon and evenness indices were calculated and used to compare species frequencies at each house. The association between climatic variables and the frequency of sand flies was evaluated using Spearman's correlation. A total of 6,265 females and 1,958 males belonging to 23 species were found. Low diversity and evenness were observed, with the dominance of Nyssomyia yuilli yuilli (Young & Porter). Ecological and diversity indices did not reveal differences between the houses. The sand fly community was composed of 3 dominant species, Ny. yuilli yuilli, Psychodopygus ayrozai (Barretto & Coutinho), and Ps. panamensis (Shannon), representing 75.8% of the total catches. No statistical association was found between the absolute frequency of sand flies, rainfall, and temperature. The results show one dominant species, this fact has epidemiological relevance since density influences parasite-vector contact. The high densities of sand flies recorded in peri- and intradomiciliary areas highlight the necessity of periodic monitoring of vector populations and control activities to reduce the risk of Leishmania transmission in this endemic area.
Assuntos
Leishmaniose Cutânea , Phlebotomus , Psychodidae , Masculino , Feminino , Animais , Colômbia/epidemiologia , Insetos Vetores , Leishmaniose Cutânea/epidemiologiaRESUMO
Next-generation sequencing (NGS) was used to investigate the genetic diversity of Leishmania tropica in the sand fly vector, targeting the internal transcribed spacer 1 (ITS1) of the genus Leishmania. Bioinformatics analyses were conducted using Galaxy, MEGA version X, DnaSP ver. 6.12.03, and PopART 1.7 software for NGS analysis, phylogenetic tree, genetic diversity, and haplotype networking, respectively. A total of 307 engorged sand flies were trapped, with an overall Leishmania infection rate of 9.4 (29/307) and 6.8% by NGS and ITS1-PCR, respectively. Two Leishmania-infected sand fly genera were identified: Phlebotomus (10.2%, 26/254) and Sergentomyia (5.7% (3/53). The phylogenetic tree showed two clusters, cluster I included the four study sequences along with 25 GenBank-retrieved DNA sequences. Cluster II consisted of three sequences from Iran and Pakistan. The genetic diversity analysis for the 29 L. tropica sequences showed high haplotype (gene) diversity index (Hd) (0.62 ± 0.07) but low nucleotide diversity index (π) (0.04 ± 0.01). Tajima's D, a neutrality test, is more negative in cluster I (D = - 2.0) than in total population (D = - 1.83), but both are equally significant (P < 0.001), indicating that observed variation in cluster I and whole population is less frequent than expected. The median-joining haplotype network produced a total of 11 active haplotypes. In conclusion, L. tropica from sand flies in Palestine is monophyletic that assembled in one main phylogroup and one haplotype.
Assuntos
Leishmania tropica , Phlebotomus , Psychodidae , Animais , Phlebotomus/genética , Leishmania tropica/genética , Haplótipos , Filogenia , Sequenciamento de Nucleotídeos em Larga Escala , Variação Genética , TecnologiaRESUMO
BACKGROUND: Leishmaniasis is a parasitic disease caused by species of the genus Leishmania, which are transmitted through the bite of infected female sand flies. Since the first reported outbreak of cutaneous leishmaniasis in Ghana, in 1999, there has been limited published information on its vectors and reservoir hosts there. Previous studies have shown strong dominance of the sand fly genus Sergentomyia over the genus Phlebotomus in Ghana. Thus the aim of this study was to determine the possible sand fly vector species in Ghana, as well as their human-feeding behavior, from the time of the first reported outbreak of CL in the country. METHODS: Sand flies were collected from randomly selected houses in three communities. They were identified and used for blood meal source identification and the detection of Leishmania infection using molecular methods. RESULTS: A total of 1051 female sand flies were morphologically identified, of which Sergentomyia africana africana (29%) was the predominant species. Among the 275 female sand flies that had blood-fed, the identified blood meal sources included chicken (33.8%) and goat (12.4%); the percentage of human blood meals was 32%. Single-source and mixed-source blood meals were identified in Sergentomyia africana africana (11.6%), Sergentomyia ingrami (14.9%) and Sergentomyia simillima (20%), with S. simillima having the highest proportion of blood meals that included human blood (14.6%). Using molecular methods, unfed sand flies and identified human-feeding species were examined for the presence of Leishmania DNA. Pool screening analysis revealed three pools of S. ingrami positive for Leishmania major DNA, with an infection rate of 1.27% (95% confidence interval 2.467-3.647). CONCLUSIONS: The findings suggest that some Sergentomyia species may be involved in the transmission of cutaneous leishmaniasis in Ghana. However, the role of S. ingrami as a vector of leishmaniasis in Ghana needs to be conclusively validated by isolating the parasite from this species and through experimental transmission studies.
Assuntos
Leishmania major , Leishmaniose Cutânea , Leishmaniose , Phlebotomus , Psychodidae , Animais , Feminino , Humanos , Phlebotomus/parasitologia , Psychodidae/parasitologia , Gana/epidemiologia , Leishmaniose Cutânea/epidemiologia , Leishmaniose Cutânea/parasitologia , Leishmaniose/epidemiologia , Surtos de Doenças , Leishmania major/genética , DNARESUMO
Sand flies (Diptera: Phlebotominae) are proven vectors of various pathogens of medical and veterinary importance. Although mostly known for their pivotal role in the transmission of parasitic protists of the genus Leishmania that cause leishmaniases, they are also proven or suspected vectors of many arboviruses, some of which threaten human and animal health, causing disorders such as human encephalitis (Chandipura virus) or serious diseases of domestic animals (vesicular stomatitis viruses). We reviewed the literature to summarize the current published information on viruses detected in or isolated from phlebotomine sand flies, excluding the family Phenuiviridae with the genus Phlebovirus, as these have been well investigated and up-to-date reviews are available. Sand fly-borne viruses from four other families (Rhabdoviridae, Flaviviridae, Reoviridae and Peribunyaviridae) and one unclassified group (Negevirus) are reviewed for the first time regarding their distribution in nature, host and vector specificity, and potential natural transmission cycles.
Assuntos
Arbovírus , Phlebovirus , Psychodidae , Rhabdoviridae , Animais , Humanos , Animais DomésticosRESUMO
BACKGROUND: Sergentomyia minuta (Diptera: Phlebotominae) is an abundant sand fly species in the Mediterranean basin and a proven vector of reptile parasite Leishmania (Sauroleishmania) tarentolae. Although it feeds preferentially on reptiles, blood meal analyses and detection of Leishmania (Leishmania) infantum DNA in wild-caught S. minuta suggest that occasional feeding may occur on mammals, including humans. Therefore, it is currently suspected as a potential vector of human pathogens. METHODS: A recently established S. minuta colony was allowed to feed on three reptile species (i.e. lizard Podarcis siculus and geckos Tarentola mauritanica and Hemidactylus turcicus) and three mammal species (i.e. mouse, rabbit and human). Sand fly mortality and fecundity were studied in blood-fed females, and the results were compared with Phlebotomus papatasi, vector of Leishmania (L.) major. Blood meal volumes were measured by haemoglobinometry. RESULTS: Sergentomyia minuta fed readily on three reptile species tested, neglected the mouse and the rabbit but took a blood meal on human. However, the percentage of females engorged on human volunteer was low in cage (3%) and feeding on human blood resulted in extended defecation times, higher post-feeding mortality and lower fecundity. The average volumes of blood ingested by females fed on human and gecko were 0.97 µl and 1.02 µl, respectively. Phlebotomus papatasi females readily fed on mouse, rabbit and human volunteer; a lower percentage of females (23%) took blood meal on the T. mauritanica gecko; reptilian blood increased mortality post-feeding but did not affect P. papatasi fecundity. CONCLUSIONS: Anthropophilic behaviour of S. minuta was experimentally demonstrated; although sand fly females prefer reptiles as hosts, they were attracted to the human volunteer and took a relatively high volume of blood. Their feeding times were longer than in sand fly species regularly feeding on mammals and their physiological parameters suggest that S. minuta is not adapted well for digestion of mammalian blood. Nevertheless, the ability to bite humans highlights the necessity of further studies on S. minuta vector competence to elucidate its potential role in circulation of Leishmania and phleboviruses pathogenic to humans.
Assuntos
Leishmania , Lagartos , Phlebotomus , Psychodidae , Feminino , Humanos , Coelhos , Animais , Camundongos , Phlebotomus/parasitologia , Psychodidae/parasitologia , Leishmania/genética , DNA/genética , Mamíferos/genéticaRESUMO
Cutaneous leishmaniasis (CL) is a prevalent infectious disease with considerable morbidity annually. Here, we aimed to investigate the likely variations in gene expression of glycoprotein63 (gp63), heat shock protein 70 (HSP70), histone, arginase, cysteine protease B (CPB), Leishmania homologue of receptors for activated C kinase (LACK), small hydrophilic endoplasmic reticulum-associated protein (SHERP) in metacyclic promastigotes of L. major isolated from Phlebotomus papatasi sand flies and promastigotes excessively cultured in culture medium. The parasites were collected from suspected CL cases in Pasteur Institute of Iran, cultured and inoculated into the female BALB/c mice (2×106 promastigotes). Sand flies were trapped in Qom province, fed with the blood of euthanized infected mice and subsequently dissected in order to isolate the midgut including stomodeal valve. The metacyclic promastigotes were isolated from Ph. papatasi (Pro-Ppap) using peanut agglutinin test (PNA), then continuously cultured in RPMI-1640 medium enriched with fetal bovine serum, penicillin (100 U/ml) and streptomycin (100 mg/ml) to reach stationary phase (Pro-Stat). The gene expression was evaluated in both parasitic stages (Pro-Ppap and Pro-Stat) using qRT-PCR. Out results showed a significant increased gene expression at Pro-Ppap stage for gp63 (P = 0.002), SHERP (P = 0.001) and histone (P = 0.026) genes, in comparison with Pro-Stat stage. Noticeably, significant changes were, also, demonstrated in 10th to 15th passages [gp63 (P = 0.041), arginase (P = 0.016), LACK (P = 0.025)] and in 5th to 20th passage (SHERP) (P = 0.029). In conclusion, the findings of the present study seem to be essential in designing Leishmania studies, in particular regarding host-parasite interaction, immunization and infectivity studies.
