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Trends in Parasitology Nov 2021The contribution of vector transmission to pathogen establishment is largely underrated. For Leishmania, transmission by sand flies is critical to early survival... (Review)
Review
The contribution of vector transmission to pathogen establishment is largely underrated. For Leishmania, transmission by sand flies is critical to early survival involving an irreproducible myriad of parasite, vector, and host molecules acting in concert to promote infection at the bite site. Here, we review recent breakthroughs that provide consequential insights into how vector transmission of Leishmania unfolds. We focus on recent work pertaining to the effect of gut microbiota, sand fly immunity, and changes in metacyclogenesis upon multiple blood meals, on Leishmania development and transmission. We also explore how sand fly saliva, egested parasite molecules and vector gut microbiota, and bleeding have been implicated in modulating the early innate host response to Leishmania, affecting the phenotype of neutrophils and monocytes arriving at the bite site.
Topics: Animals; Disease Vectors; Gastrointestinal Microbiome; Leishmania; Leishmaniasis; Psychodidae
PubMed: 34389215
DOI: 10.1016/j.pt.2021.07.003 -
Trends in Parasitology Sep 2020
Review
Topics: Animal Distribution; Animals; Insect Control; Insect Vectors; Leishmania infantum; Leishmaniasis, Visceral; Life Cycle Stages; Psychodidae
PubMed: 32467046
DOI: 10.1016/j.pt.2020.05.007 -
Veterinary Research Communications Dec 2023Leishmania is a genus of parasitic protozoa that causes a disease called leishmaniasis. Leishmaniasis is transmitted to humans through the bites of infected female... (Review)
Review
Leishmania is a genus of parasitic protozoa that causes a disease called leishmaniasis. Leishmaniasis is transmitted to humans through the bites of infected female sandflies. There are several different species of Leishmania that can cause various forms of the disease, and the symptoms can range from mild to severe, depending on species of Leishmania involved and the immune response of the host. Leishmania parasites have a variety of reservoirs, including humans, domestic animals, horses, rodents, wild animals, birds, and reptiles. Leishmaniasis is endemic of 90 countries, mainly in South American, East and West Africa, Mediterranean region, Indian subcontinent, and Central Asia. In recent years, cases have been detected in other countries, and it is already an infection present throughout the world. The increase in temperatures due to climate change makes it possible for sandflies to appear in countries with traditionally colder regions, and the easy movement of people and animals today, facilitate the appearance of Leishmania species in new countries. These data mean that leishmaniasis will probably become an emerging zoonosis and a public health problem in the coming years, which we must consider controlling it from a One Health point of view. This review summarizes the prevalence of Leishmania spp. around the world and the current knowledge regarding the animals that could be reservoirs of the parasite.
Topics: Humans; Female; Animals; Horses; Leishmaniasis; Zoonoses; Leishmania; Psychodidae; Rodentia; Horse Diseases
PubMed: 37438495
DOI: 10.1007/s11259-023-10171-5 -
Parasitology Research Dec 2023Leishmaniasis transmission cycles are maintained and sustained in nature by the complex crosstalk of the Leishmania parasite, sandfly vector, and the mammalian hosts... (Review)
Review
Leishmaniasis transmission cycles are maintained and sustained in nature by the complex crosstalk of the Leishmania parasite, sandfly vector, and the mammalian hosts (human, as well as zoonotic reservoirs). Regardless of the vast research on human host-parasite interaction, there persists a substantial knowledge gap on the parasite's development and modulation in the vector component. This review focuses on some of the intriguing aspects of the Leishmania-sandfly interface, beginning with the uptake of the intracellular amastigotes from an infected host to the development of the parasite within the sandfly's alimentary canal, followed by the transmission of infective metacyclic stages to another potential host. Upon ingestion of the parasite, the sandfly hosts an intricate repertoire of immune barriers, either to evade the parasite or to ensure its homeostatic coexistence with the vector gut microbiome. Sandfly salivary polypeptides and Leishmania exosomes are co-egested with the parasite inoculum during the infected vector bite. This has been attributed to the modulation of the parasite infection and subsequent clinical manifestation in the host. While human host-based studies strive to develop effective therapeutics, a greater understanding of the vector-parasite-microbiome and human host interactions could help us to identify the targets and to develop strategies for effectively preventing the transmission of leishmaniasis.
Topics: Animals; Humans; Leishmania; Psychodidae; Parasites; Phlebotomus; Leishmaniasis; Host-Parasite Interactions; Mammals
PubMed: 38052752
DOI: 10.1007/s00436-023-08043-7 -
Frontiers in Cellular and Infection... 2023is a zoonotic Old World parasite transmitted by Phlebotomine sand flies and causing cutaneous leishmaniasis in Ethiopia and Kenya. Despite a range of clinical...
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, is one of the most neglected species of the genus in terms of scientific attention. Here, we explored the genome diversity of by analyzing the genomes of twenty isolates from Ethiopia. Phylogenomic analyses identified two strains as interspecific hybrids involving as one parent and and 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 - hybrid was diploid and the - hybrid was triploid, as has been described for other interspecific hybrids. When focusing on , 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 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 genomics revealed new insights into the genomic consequences of both meiotic and mitotic recombination in .
Topics: Animals; Leishmania; Leishmaniasis, Cutaneous; Psychodidae; Phylogeny; Nucleic Acid Hybridization
PubMed: 37153154
DOI: 10.3389/fcimb.2023.1147998 -
Transactions of the Royal Society of... Sep 2023Cutaneous leishmaniasis (CL) is a parasitic vector-borne disease affecting mostly low- and middle-income countries. CL is endemic in Guatemala, where an increase in the... (Review)
Review
Cutaneous leishmaniasis (CL) is a parasitic vector-borne disease affecting mostly low- and middle-income countries. CL is endemic in Guatemala, where an increase in the number of cases and incidence and a changing disease distribution in the past decade have been reported. Important research was conducted in Guatemala in the 1980s and 1990s to understand the epidemiology of CL and two Leishmania species were identified as the aetiologic agents. Several species of sand flies have been reported, five of which are naturally infected with Leishmania. Clinical trials conducted in the country evaluated different treatments against the disease and provided solid evidence for CL control strategies that are applicable worldwide. More recently, in the 2000s and 2010s, qualitative surveys were conducted to understand community perceptions of the disease and to highlight the challenges and enablers for disease control. However, limited recent data have been generated regarding the current CL situation in Guatemala, and key information necessary for effective disease control, such as incrimination of vectors and reservoirs, is still lacking. This review describes the current state of knowledge of CL in Guatemala, including the main parasite and sand fly species, disease reservoirs, diagnosis and control, as well as the perceptions of communities in endemic regions.
Topics: Animals; Guatemala; Leishmaniasis, Cutaneous; Leishmania; Phlebotomus; Psychodidae; Leishmaniasis
PubMed: 37103337
DOI: 10.1093/trstmh/trad024 -
Current Opinion in Microbiology Dec 2021Protozoa of the genus Leishmania are intracellular parasites that cause human leishmaniasis, a disease spread mostly in the tropics and subtropics. Leishmania cycle... (Review)
Review
Protozoa of the genus Leishmania are intracellular parasites that cause human leishmaniasis, a disease spread mostly in the tropics and subtropics. Leishmania cycle between the midgut of female sand flies and phagolysosome of mammalian macrophages. During their life cycle they constantly encounter changing nutritional environments. To monitor the external concentration of essential nutrients, the invading parasites employ sensors that report on the availability of these nutrients; but to-date only a few sensing pathways have been identified in Leishmania. This review focuses on the Arginine Deprivation Response, which both extracellular and intracellular Leishmania utilize to monitor environmental arginine and adjust their arginine transporter (AAP3) levels accordingly.
Topics: Animals; Arginine; Female; Humans; Leishmania; Leishmaniasis; Phagosomes; Psychodidae
PubMed: 34592588
DOI: 10.1016/j.mib.2021.09.003 -
The Journal of General Virology Apr 2023Sand flies (Diptera: Phlebotominae) are proven vectors of various pathogens of medical and veterinary importance. Although mostly known for their pivotal role in the... (Review)
Review
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 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 with the genus , as these have been well investigated and up-to-date reviews are available. Sand fly-borne viruses from four other families (, , and ) and one unclassified group () are reviewed for the first time regarding their distribution in nature, host and vector specificity, and potential natural transmission cycles.
Topics: Animals; Humans; Psychodidae; Phlebovirus; Animals, Domestic; Arboviruses; Rhabdoviridae
PubMed: 37018120
DOI: 10.1099/jgv.0.001837 -
Frontiers in Cellular and Infection... 2022Parasites of the genus , together with the genus , form a sister clade to the species-rich and medically important genus . Both species, and , are dixenous parasites...
Parasites of the genus , together with the genus , form a sister clade to the species-rich and medically important genus . Both species, and , are dixenous parasites of Neotropical porcupines. Almost 50 years after their first discovery, knowledge of their life cycle remains poor and their insect vectors are unknown. Because competent vectors of their closest phylogenetic relatives, genera and , are phlebotomine sand flies (Diptera: Psychodidae) and/or biting midges (Diptera: Ceratopogonidae), we examined here the potential of both sand flies and biting midges to transmit parasites. The insects ( and ) were exposed to parasites through the chicken skin membrane and dissected at various time intervals post bloodmeal. Potentially infected females were also allowed to feed on the ears of anaesthetized BALB/c mice and the presence of parasite DNA was subsequently confirmed in the mice by PCR. did not survive defecation in or , suggesting that these sand fly species are unlikely to serve as natural vectors of this parasite. Similarly, infections were lost in midges. In contrast, mature infections developed in 51-61% of females, 7.3% of females and 7.7% of females. In all three vector species, colonized predominantly Malpighian tubules and produced metacyclic infective forms. Transmission of to BALB/c mice was demonstrated the prediuresis of females. This mode of transmission, as well the colonization of Malpighian tubules as the dominant tissue of the vector, is unique among trypanosomatids. In conclusion, we demonstrated the vector competence of for but not for , and further studies are needed to evaluate competence of other Neotropical vectors for these neglected parasites.
Topics: Animals; Female; Insect Vectors; Leishmania; Life Cycle Stages; Mice; Phylogeny; Psychodidae
PubMed: 36034718
DOI: 10.3389/fcimb.2022.981071 -
MBio Dec 2022Genetic exchange between different strains in the sand fly vector has been experimentally demonstrated and is supported by population genetic studies. In nature,...
Genetic exchange between different strains in the sand fly vector has been experimentally demonstrated and is supported by population genetic studies. In nature, opportunities for interstrain mating are restricted to flies biting multiply infected hosts or through multiple bites of different hosts. In contrast, self-mating could occur in any infected sand fly. By crossing two recombinant lines derived from the same Leishmania major strain, each expressing a different drug-resistance marker, self-hybridization in L. major was confirmed in a natural sand fly vector, , and in frequencies comparable to interstrain crosses. We provide the first high resolution, whole-genome sequencing analysis of large numbers of selfing progeny, their parents, and parental subclones. Genetic exchange consistent with classical meiosis is supported by the biallelic inheritance of the rare homozygous single nucleotide polymorphisms (SNPs) that arose by mutation during the generation of the parental clones. In contrast, heterozygous SNPs largely failed to be transmitted in Mendelian ratios for reasons not understood. SNPs that were heterozygous in both parents, however, recombined to produce homozygous alleles in some hybrids. For trisomic chromosomes present in both parents, transmittal to the progeny was only altered by self-hybridization, involving a gain or loss of somy in frequencies predicted by a meiotic process. Whole-genome polyploidization was also observed in the selfing progeny. Thus, self-hybridization in , with its potential to occur in any infected sand fly, may be an important source of karyotype variation, loss of heterozygosity, and functional diversity. are parasitic protozoa that cause a wide spectrum of diseases collectively known as the leishmaniases. Sexual reproduction in has been proposed as an important source of genetic diversity and has been formally demonstrated to occur inside the sand fly vector midgut. Nevertheless, in the wild, opportunities for genetic exchange between different species or strains are restricted by the capacity of different strains to colonize the same sand fly. In this work, we report the first high resolution, whole-genome sequence analysis of intraclonal genetic exchange as a type of self-mating in Our data reveal that self-hybridization can occur with comparable frequency as interstrain mating under experimental lab conditions, leading to important genomic alterations that can potentially take place within every naturally infected sand fly.
Topics: Animals; Leishmania major; Phlebotomus; Psychodidae; Reproduction; Mutation
PubMed: 36394334
DOI: 10.1128/mbio.02858-22