scholarly journals Development of Various Leishmania (Sauroleishmania) tarentolae Strains in Three Phlebotomus Species

2021 ◽  
Vol 9 (11) ◽  
pp. 2256
Author(s):  
Lucie Ticha ◽  
Barbora Kykalova ◽  
Jovana Sadlova ◽  
Marina Gramiccia ◽  
Luigi Gradoni ◽  
...  

Leishmania (Sauroleishmania) tarentolae is transmitted by reptile-biting sand flies of the genus Sergentomyia, but the role of Phlebotomus sand flies in circulation of this parasite is unknown. Here, we compared the development of L. (S.) tarentolae strains in three Phlebotomus species: P. papatasi, P. sergenti, and P. perniciosus. Laboratory-bred sand flies were membrane-fed on blood with parasite suspension and dissected on days 1 and 7 post blood meal. Parasites were measured on Giemsa-stained gut smears and five morphological forms were distinguished. In all parasite-vector combinations, promastigotes were found in Malpighian tubules, often in high numbers, which suggests that this tissue is a typical location for L. (S.) tarentolae development in sand flies. All three studied strains colonized the hindgut, but also migrated anteriorly to both parts of the midgut and colonized the stomodeal valve. Significant differences were demonstrated between sand fly species: highest infection rates, high parasite loads, and the most frequent anterior migration with colonization of the stomodeal valve were found in P. perniciosus, while all these parameters were lowest in P. sergenti. In conclusion, the peripylarian type of development was demonstrated for three L. (S.) tarentolae strains in three Phlebotomus sand flies. We suggest paying more attention to Phlebotomus species, particularly P. perniciosus and P. papatasi, as potential secondary vectors of Sauroleishmania.

2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
Mattia Calzolari ◽  
Gianluca Rugna ◽  
Emanuela Clementi ◽  
Elena Carra ◽  
Marco Pinna ◽  
...  

The Trypanosoma theileri group includes several trypanosome species hardly distinguishable due to the lack of discriminating morphological characters. Trypanosomes belonging to this group have been isolated from different bovine, ovine, and cervids in Europe, Africa, Asia, and Americas. The principal vectors of the T. theileri group are considered tabanid flies; however, T. melophagium is transmitted exclusively by sheep keds. In 2016, 128 sand flies out of 2,728 trapped in Valsamoggia municipality, Italy, were individually dissected and an unknown trypanosome strain, named TrPhp1, was isolated from a female of the sand fly Phlebotomus perfiliewi. Sequence analysis placed this trypanosome in the T. theileri group with very high homology to other trypanosomes detected in European cervids. This is the first report of the T. theileri group isolation from a sand fly, and the possible role of this insect group in the trypanosome transmission cycle is discussed. Within the T. theileri group, the phylogenetic analysis distinguished several lineages, which, unfortunately, do not correspond with their host specificity and their taxonomic status remains ambiguous.


2020 ◽  
Author(s):  
Mariana M. Chaves ◽  
Sang Hun Lee ◽  
Olena Kamenyeva ◽  
Kashinath Ghosh ◽  
David Sacks

AbstractThere is substantial experimental evidence to indicate that Leishmania infections that are transmitted naturally by the bites of infected sand flies differ in fundamental ways from the inflammatory and immune reactions initiated by needle inocula. We have used flow cytometry and intravital microscopy (IVM) to reveal the heterogeneity of sand fly transmission sites with respect to the subsets of phagocytes in the skin that harbor L. major within the first hours and days after infection. By flow cytometry analysis, dermis resident macrophages (TRMs) were on average the predominant infected cell type at 1 hr and 24 hr. By confocal IVM, the co-localization of L. major and neutrophils varied depending on the proximity of deposited parasites to the presumed site of vascular damage, defined by the highly localized swarming of neutrophils. Some of the dermal TRMs could be visualized acquiring their infections via transfer from or efferocytosis of parasitized neutrophils, providing direct evidence for the “Trojan Horse” model. The role of neutrophil engulfment by dermal TRMs and the involvement of the Tyro3/Axl/Mertk family of receptor tyrosine kinases in these interactions and in sustaining the anti-inflammatory program of dermal TRMs was supported by the effects observed in neutrophil depleted and in Axl-/-Mertk-/- mice. The Axl-/-Mertk-/- mice also displayed reduced parasite burdens but more severe pathology following L. major infection transmitted by sand fly bite.SummarySand flies transmit Leishmania major which causes cutaneous leishmaniasis in humans and in non-human hosts. Our analyses of sand fly transmission sites of L. major in the mouse skin revealed that dermis resident macrophages (TRM) were the predominant phagocytes to take up the parasite within the first 24 hr post-bite. The early involvement of neutrophils varied depending on the proximity of deposited parasites to the site of tissue damage around which the neutrophils coalesced. By intra-vital microscopy, some of the dermal TRMs could be visualized acquiring their infections by direct transfer from or phagocytosis of parasitized neutrophils. The involvement of the Tyro3/Axl/Mertk family of receptor tyrosine kinases in these cellular interactions and in sustaining the anti-inflammatory functions of dermal TRMs was supported by the reduced parasite burdens but more severe pathology observed in Axl-/-Mertk-/- mice. The heterogeneity of sand fly transmission sites with respect to the dose of parasites and the early cellular interactions described here likely contribute to the wide range of infection outcomes that are associated with natural transmission of L. major observed in mouse models and possibly humans.


2020 ◽  
Vol 57 (5) ◽  
pp. 1510-1515 ◽  
Author(s):  
M Emin Limoncu ◽  
İ Cüneyt Balcıoğlu ◽  
Seray Töz ◽  
Samiye Demir ◽  
Hakan Kavur ◽  
...  

Abstract Cutaneous (CL) and visceral (VL) forms of leishmaniasis, transmitted by sand flies, are seen in all countries located in Mediterranean Basin including Turkey. In this study, we aimed to conduct an entomological survey for the detection of sand fly fauna and vector species in Mersin province, one of the important endemic areas for CL in Turkey. In total, 912 sand fly specimens were collected in 2010 and 2011 using CDC light traps. Nine Phlebotomus (Diptera: Psychodidae) and three Sergentomyia (Diptera: Psychodidae) species were detected. Of the collected Phlebotomus sand flies, P. sergenti Parrot, 1917 (30.1%) was the most dominant followed by P. alexandri Sinton, 1928 (18.2%), P. neglectus/syriacus Tonnoir Adler (12.0%), P. tobbi Adler & Theodor, 1930 (11.7%), and P. papatasi Scopoli, 1786 (10.2%), while S. minuta Rondani, 1843 (11.3%) was the dominant species among Sergentomyia. During the field work in 2011, female specimens (n = 81) were screened for the presence of Leishmania promastigotes by midgut dissection, and all were found negative. The rest of the collected female specimens (n = 334) were pooled according to species (P. alexandri, P. neglectus/syriacus, P. papatasi, P. sergenti, P. simici, and P. tobbi) and location (Mut, Silifke, and Anamur). In total, 29 pools were generated and real-time ITS1 PCR assay was performed to detect and identify natural Leishmania Ross, 1903 (Kinetoplastida: Trypanosomatida) infection. Two pools, both from Mut town, containing P. sergenti specimens were found positive and Leishmania tropica Ross, 1903 was identified as an infectious agent for both pools. In conclusion, the sand fly fauna was determined in an endemic area for CL. The detection of L. tropica DNA in P. sergenti specimens showed the possible vectorial role of this species in Mersin province.


2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
C. S. Moraes ◽  
K. Aguiar-Martins ◽  
S. G. Costa ◽  
P. A. Bates ◽  
R. J. Dillon ◽  
...  

Lutzomyia longipalpis is the main vector of visceral leishmaniasis (VL) in America. Physiological and molecular mechanisms of Leishmania infection in sand flies have been studied during the first gonotrophic cycle. There are few studies about these interactions during the second gonotrophic cycle mainly because of the difficulties maintaining sand flies through sequential feeds. Here we standardized conditions to perform the second blood feed efficiently, and our results show that oviposition is an essential factor for the success of multiple feeds. We evaluated the impact of the second blood meal on longevity, protein digestion, trypsin activity, and Leishmania mexicana development within L. longipalpis gut. Mortality of blood-fed females increases after second blood meal as compared to sugar-fed females. Trypsin activity was lower during the second gonotrophic cycle. However, no difference in protein intake was observed between blood meals. There was no difference in the population size of Leishmania in the gut after both blood meals. In this work, we presented an optimized protocol for obtaining sufficient numbers of sand fly females fed on a second blood meal, and we described some physiological and parasitological aspects of the second gonotrophic cycle which might influence the vectorial competence of sand flies.


2020 ◽  
Author(s):  
Kelsilandia A. Martins ◽  
Caroline S. Morais ◽  
Susan J. Broughton ◽  
Claudio R. Lazzari ◽  
Paul A. Bates ◽  
...  

AbstractThe phlebotomine sand fly Lutzomyia longipalpis is the primary insect vector of visceral leishmaniasis in the Americas. For ectothermic organisms such as sand flies, the ambient temperature is a critical factor influencing all aspects of their life. However, the impact of temperature has been ignored in previous investigations of stress-induced responses by the vector, such as taking a blood meal or during Leishmania infection. Therefore, this study explored the interaction of Lu. longipalpis with temperature by evaluating sand fly behaviour across a thermal gradient after sugar or blood-feeding, and infection with Leishmania mexicana. Thermographic recordings of sand fly females fed on mice were analysed, and the gene expression of heat shock proteins HSP70 and HSP90(83) was evaluated when insects were exposed to extreme temperatures or infected. The results showed that 72h after blood ingestion females of Lu. longipalpis became less active and preferred relatively low temperatures. However, at later stages of blood digestion females increased their activity and remained at higher temperatures prior to taking a second blood meal; this behaviour seems to be correlated with the evolution of their oocysts and voracity for a second blood meal. No changes in the temperature preferences of female sand flies were recorded in the presence of a gut infection by Le. mexicana, indicating that this parasite has not triggered behavioural immunity in Lu. longipalpis. Real-time imaging showed that the body temperature of female flies feeding on mice increased to the same temperature as the host within a few seconds after landing. The body temperature of females remained around 35 ± 0.5 °C until the end of blood-feeding, revealing a lack of thermoregulatory behaviour. Analysis of expression of heat shock proteins revealed insects increased expression of HSP90(83) when exposed to higher temperatures, such as during blood feeding. Our findings suggest that Lu. longipalpis interacts with the environmental temperature by using its behaviour to avoid temperature-related physiological damage during the gonotrophic cycle. However, the expression of certain heat shock proteins might be triggered to mitigate against thermal stress in situations where a behavioural response is not the best option.


2019 ◽  
Author(s):  
Myrthe Pareyn ◽  
Abena Kochora ◽  
Luca Van Rooy ◽  
Nigatu Eligo ◽  
Bram Vanden Broecke ◽  
...  

AbstractBackgroundCutaneous leishmaniasis (CL) is a major public health concern in Ethiopia. However, knowledge about the complex zoonotic transmission cycle is limited, hampering implementation of control strategies. We explored the feeding behavior and activity of the vector (Phlebotomus pedifer) and established the role of livestock in CL transmission.MethodsBlood meal origins of engorged sand flies were determined by sequencing host DNA. A host choice experiment was performed to assess the feeding preference of P. pedifer when humans and hyraxes are equally accessible. Ear and nose biopsies from goats and bovines were screened for the presence of Leishmania parasites. Sand flies were captured indoor and outdoor with human landing catches (HLC) and CDC light traps to determine at which time and where P. pedifer is mostly active.Principal findingsA total of 180 sand flies were found to bite hosts of 12 genera. Humans were the predominant blood meal source (59.4%, p < 0.001) in all habitats, even in caves, where hyraxes are abundant. Only 10.6% of the sand flies fed on hyraxes based on the blood meal analysis, but the host choice experiment revealed that sand flies have a significant preference for feeding on hyraxes over humans (p = 0.009) when hosts are equally accessible. Only a single goat nose biopsy from 412 animal samples was found with Leishmania RNA. We found that P. pedifer is predominantly endophagic (p = 0.003), but occurs both indoors and outdoors. A substantial amount of sand flies was active in the early evening, which increased over time reaching its maximum around midnight.ConclusionWe indicate that Leishmania transmission in southwestern Ethiopia is, in contrast to earlier suggestions, likely mainly anthroponotic and that livestock does not play a role in transmission. Combined indoor and outdoor vector control measures at night are required for efficient vector control.Author summaryCutaneous leishmaniasis is a major public health problem in Ethiopia. It is caused by Leishmania aethiopica protozoa that are transmitted when female sand flies take a blood meal. Hyraxes are assigned as the reservoirs of the infection, because many were found infected with Leishmania. There is very limited knowledge about the behavior of sand flies and other potential hosts of the infection. However, this information is a prerequisite for disease control, which is currently hampered. In this study, we found that humans are likely the main source of the infection and that the role of hyraxes in disease transmission needs further investigation to decide whether they should be included in control programs. Livestock appears not play a role in transmission, even though sand flies like to feed on them. We also show that sand flies are active indoors and outdoors, but have a preference for feeding inside human dwellings and that they are mostly active around midnight. Overall, we conclude that disease prevention and control should emphasize on human protection by applying vector control indoors, at night.


2020 ◽  
Vol 57 (4) ◽  
pp. 1286-1292 ◽  
Author(s):  
Felipe Dutra Rêgo ◽  
Getúlio Dornelles Souza ◽  
Júlia Bahia Miranda ◽  
Lais Vieira Peixoto ◽  
José Dilermando Andrade-Filho

Abstract In view of recent cases of human and canine visceral leishmaniasis reported in Porto Alegre, Rio Grande do Sul, Brazil, we investigated the sand fly fauna inhabiting the neighborhoods of Morro Santana and Jardim Carvalho, Brazil, continuing a series of entomological surveys aimed to identify potential vectors of Leishmania (Ross, 1903) parasites. Sand flies were collected monthly from October 2016 to October 2017 using CDC light traps in the intradomiciliary and peridomiciliary environments of seven residences. Sand fly abundance was correlated to climatic variables. Females were pooled by species, location, and date for Leishmania DNA molecular screening using ITS1 and kDNA polymerase chain reaction. In total, 501 sand flies from five species were collected in which Lutzomyia gaminarai (Cordero, Vogelsang & Cossio, 1928) (Diptera: Psychodidae) (78%) was the most abundant species in the intradomiciliary sites while Migonemyia migonei (Franca, 1920) (Diptera: Psychodidae) (43.3%) was the most abundant in the peridomiciliary sites. A higher number of sand flies were collected during the warmest months, from December to March (Mann–Whitney statistical test – P &lt; 0.001). Leishmania infantum DNA was detected in Lu. gaminarai (2), Pintomyia fischeri (Pinto, 1926) (1) and Mg. migonei (1). Leishmania braziliensis DNA was detected in Lu. gaminarai (1) and Pi. fischeri (1). Our results add support to the possible vector role of Pi. fischeri in the epidemiological cycle of Le. infantum in Brazil. Furthermore, the first documented detection of Leishmania DNA in Lu. gaminarai may be indicative of multiple vectors being involved in the Leishmania cycle within Porto Alegre.


Author(s):  
Madhavi L Kakumanu ◽  
Bahjat F Marayati ◽  
Coby Schal ◽  
Charles S Apperson ◽  
Gideon Wasserberg ◽  
...  

Abstract Phlebotomine sand flies are worldwide vectors of Leishmania parasites as well as other bacterial and viral pathogens. Due to the variable impact of traditional vector control practices, a more ecologically based approach is needed. The goal of this study was to isolate bacteria from the most attractive substrate to gravid Phlebotomus papatasi Scopoli sand flies and determine the role of bacterial volatiles in the oviposition attractancy of P. papatasi using behavioral assays. We hypothesized that gravid sand flies are attracted to bacterially derived semiochemical cues associated with breeding sites. Bacteria were isolated from a larvae-conditioned rearing medium, previously shown to be highly attractive to sand flies. The isolated bacteria were identified by amplifying and sequencing 16S rDNA gene fragments, and 12 distinct bacterial species were selected for two-choice olfactometer bioassays. The mix of 12 bacterial isolates elicited strong attraction at the lower concentration of 107 cells per ml and significant repellence at a high concentration of 109 cells per ml. Three individual isolates (SSI-2, SSI-9, and SSI-11) were particularly attractive at low doses. In general, we observed dose-related effects, with some bacterial isolates stimulating negative and some positive dose–response curves in sand fly attraction. Our study confirms the important role of saprophytic bacteria, gut bacteria, or both, in guiding the oviposition-site selection behavior of sand flies. Identifying the specific attractive semiochemical cues that they produce could lead to development of an attractive lure for surveillance and control of sand flies.


2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Barrack O. Owino ◽  
Jackline Milkah Mwangi ◽  
Steve Kiplagat ◽  
Hannah Njiriku Mwangi ◽  
Johnstone M. Ingonga ◽  
...  

Abstract Background Visceral leishmaniasis (VL) and zoonotic cutaneous leishmaniasis (ZCL) are of public health concern in Merti sub-County, Kenya, but epidemiological data on transmission, vector abundance, distribution, and reservoir hosts remain limited. To better understand the disease and inform control measures to reduce transmission, we investigated the abundance and distribution of sand fly species responsible for Leishmania transmission in the sub-County and their blood-meal hosts. Methods We conducted an entomological survey in five villages with reported cases of VL in Merti sub-County, Kenya, using CDC miniature light traps and castor oil sticky papers. Sand flies were dissected and identified to the species level using standard taxonomic keys and PCR analysis of the cytochrome c oxidase subunit 1 (cox1) gene. Leishmania parasites were detected and identified by PCR and sequencing of internal transcribed spacer 1 (ITS1) genes. Blood-meal sources of engorged females were identified by high-resolution melting analysis of vertebrate cytochrome b (cyt-b) gene PCR products. Results We sampled 526 sand flies consisting of 8 species, Phlebotomus orientalis (1.52%; n = 8), and 7 Sergentomyia spp. Sergentomyia squamipleuris was the most abundant sand fly species (78.71%; n = 414) followed by Sergentomyia clydei (10.46%; n = 55). Leishmania major, Leishmania donovani, and Trypanosoma DNA were detected in S. squamipleuris specimens. Humans were the main sources of sand fly blood meals. However, we also detected mixed blood meals; one S. squamipleuris specimen had fed on both human and mouse (Mus musculus) blood, while two Ph. orientalis specimens fed on human, hyrax (Procavia capensis), and mouse (Mus musculus) blood. Conclusions Our findings implicate the potential involvement of S. squamipleuris in the transmission of Leishmania and question the dogma that human leishmaniases in the Old World are exclusively transmitted by sand flies of the Phlebotomus genus. The presence of Trypanosoma spp. may indicate mechanical transmission, whose efficiency should be investigated. Host preference analysis revealed the possibility of zoonotic transmission of leishmaniasis and other pathogens in the sub-County. Leishmania major and L. donovani are known to cause ZCL and VL, respectively. However, the reservoir status of the parasites is not uniform. Further studies are needed to determine the reservoir hosts of Leishmania spp. in the area.


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