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Parasites & Vectors Jan 2014Lutzomyia gomezi (Nitzulescu, 1931) is one of the main Leishmania (Vianna) panamensis vectors in Panama, and despite its medical significance, there are no population...
BACKGROUND
Lutzomyia gomezi (Nitzulescu, 1931) is one of the main Leishmania (Vianna) panamensis vectors in Panama, and despite its medical significance, there are no population genetic studies regarding this species. In this study, we used the sequences of the mitochondrial gene cytochrome b/start of NADH1 and the nuclear elongation gene α-1 in order to analyze genetic variation and phylogeographic structure of the Lu. gomezi populations.
METHODS
A total of 86 Lu. gomezi individuals were captured in 38 locations where cutaneous leishmaniasis occurred. DNA was extracted with phenol/chloroform methods and amplification of genes was performed using PCR primers for mitochondrial and nuclear markers.
RESULTS
We found a total of 37 and 26 haplotypes of mitochondrial and nuclear genes, high haplotype diversity (h) for all three populations were detected with both molecular markers. Nucleotide diversity (π) was estimated to be high for all three populations with the mitochondrial marker, which was opposite to the estimate with the nuclear marker. In the AMOVA Φst recorded moderate (mitochondrial) and small (nuclear) population structure with statistical significance among populations. The analysis of the fixation index (Fst) used to measure the differentiation of populations showed that with the exception of the population located in the region of Bocas del Toro, the other populations presented with minor genetic differentiation. The median-Joining network of the mitochondrial marker reveled three clusters and recorded four haplotypes exclusively of localities sampled from Western Panama, demonstrating strong divergence. We found demographic population expansion with Fu´s Fs neutrality test. In the analysis mismatch distribution was observed as a bimodal curve.
CONCLUSION
Lu. gomezi is a species with higher genetic pool or variability and mild population structure, due to possible capacity migration and local adaptation to environmental changes or colonization potential. Thus, knowledge of the genetic population and evolutionary history is useful to understand the implications of different population genetic structures for cutaneous leishmaniasis epidemiology.
Topics: Animals; Cluster Analysis; Genes, Insect; Genetic Variation; Geography; Haplotypes; Panama; Phylogeography; Psychodidae
PubMed: 24398187
DOI: 10.1186/1756-3305-7-9 -
PLoS Neglected Tropical Diseases Apr 2018The peritrophic matrix (PM) is an acellular chitin-containing envelope which in most blood sucking insects encloses the ingested blood meal and protects the midgut...
BACKGROUND
The peritrophic matrix (PM) is an acellular chitin-containing envelope which in most blood sucking insects encloses the ingested blood meal and protects the midgut epithelium. Type I PM present in sand flies and other blood sucking batch feeders is secreted around the meal by the entire midgut in response to feeding. Here we tested the hypothesis that in Sergentomyia schwetzi the PM creates a physical barrier that prevents escape of Leishmania parasites from the endoperitrophic space.
METHODOLOGY/PRINCIPAL FINDINGS
Morphology and ultrastructure of the PM as well the production of endogenous chitinase in S. schwetzi were compared with three sand fly species, which are natural vectors of Leishmania. Long persistence of the PM in S. schwetzi was not accompanied by different morphology or decreased production of chitinase. To confirm the role of the PM in refractoriness of S. schwetzi to Leishmania parasites, culture supernatant from the fungus Beauveria bassiana containing chitinase was added to the infective bloodmeal to disintegrate the PM artificially. In females treated with B. bassiana culture supernatants the PM was weakened and permeable, lacking multilayered inner structure; Leishmania colonized the midgut and the stomodeal valve and produced metacyclic forms. In control females Leishmania infections were lost during defecation.
CONCLUSIONS/SIGNIFICANCE
Persistence of the PM till defecation of the bloodmeal represents an important factor responsible for refractoriness of S. schwetzi to Leishmania development. Leishmania major as well as L. donovani promastigotes survived defecation and developed late-stage infections only in females with PM disintegrated artificially by B. bassiana culture supernatants containing exogenous chitinase.
Topics: Animals; Digestive System; Female; Insect Vectors; Leishmania major; Psychodidae; Rabbits
PubMed: 29617364
DOI: 10.1371/journal.pntd.0006382 -
PLoS Neglected Tropical Diseases Mar 2015American visceral leishmaniasis (AVL) is an emerging disease in the state of São Paulo, Brazil. Its geographical expansion and the increase in the number of human cases...
BACKGROUND
American visceral leishmaniasis (AVL) is an emerging disease in the state of São Paulo, Brazil. Its geographical expansion and the increase in the number of human cases has been linked to dispersion of Lutzomyia longipalpis into urban areas. To produce more accurate risk maps we investigated the geographic distribution and routes of expansion of the disease as well as chemotype populations of the vector.
METHODOLOGY/PRINCIPAL FINDINGS
A database, containing the annual records of municipalities which had notified human and canine AVL cases as well as the presence of the vector, was compiled. The chemotypes of L. longipalpis populations from municipalities in different regions of São Paulo State were determined by Coupled Gas Chromatography - Mass Spectrometry. From 1997 to June 2014, L. longipalpis has been reported in 166 municipalities, 148 of them in the Western region. A total of 106 municipalities were identified with transmission and 99 were located in the Western region, where all 2,204 autochthonous human cases occurred. Both the vector and the occurrence of human cases have expanded in a South-easterly direction, from the Western to central region, and from there, a further expansion to the North and the South. The (S)-9-methylgermacrene-B population of L. longipalpis is widely distributed in the Western region and the cembrene-1 population is restricted to the Eastern region.
CONCLUSION/SIGNIFICANCE
The maps in the present study show that there are two distinct epidemiological patterns of AVL in São Paulo State and that the expansion of human and canine AVL cases through the Western region has followed the same dispersion route of only one of the two species of the L. longipalpis complex, (S)-9-methylgermacrene-B. Entomological vigilance based on the routes of dispersion and identification of the chemotype population could be used to identify at-risk areas and consequently define the priorities for control measures.
Topics: Animals; Brazil; Dogs; Gas Chromatography-Mass Spectrometry; Geographic Information Systems; Humans; Insect Vectors; Leishmaniasis, Visceral; Male; Psychodidae
PubMed: 25781320
DOI: 10.1371/journal.pntd.0003620 -
Journal of Medical Entomology Feb 2019Trichophoromyia iorlandobaratai sp. n. Vasconcelos dos Santos, Santos Neto, Sánchez Uzcátegui & Galardo is described and illustrated on the basis of male specimens...
Trichophoromyia iorlandobaratai sp. n. Vasconcelos dos Santos, Santos Neto, Sánchez Uzcátegui & Galardo is described and illustrated on the basis of male specimens collected in the municipality of Itaituba, Pará State, Brazilian Amazonia. This species can be differentiated from other morphologically similar species within Trichophoromyia by means of the male characters such as the ratio between the aedeagal ducts/sperm pump, shape and distribution of setae in the gonocoxite, and particularly the distinct shape of paramere.
Topics: Animals; Brazil; Male; Psychodidae
PubMed: 30398657
DOI: 10.1093/jme/tjy194 -
Antimicrobial Agents and Chemotherapy Oct 2014We studied the development of antimony-resistant Leishmania infantum in natural vectors Lutzomyia longipalpis and Phlebotomus perniciosus to ascertain the risk of...
We studied the development of antimony-resistant Leishmania infantum in natural vectors Lutzomyia longipalpis and Phlebotomus perniciosus to ascertain the risk of parasite transmission by sand flies. All three resistant strains produced fully mature late-stage infections in sand flies; moreover, the resistant phenotype was maintained after the passage through the vector. These results highlight the risk of circulation of resistant Leishmania strains and question the use of human drugs for treatment of dogs as Leishmania reservoirs.
Topics: Animals; Antimony; Insect Vectors; Leishmania; Leishmania infantum; Phlebotomus; Psychodidae
PubMed: 25049256
DOI: 10.1128/AAC.02406-13 -
Parasites & Vectors Jul 2012Microbial ecology of phlebotomine sand flies is not well understood although bacteria likely play an important role in the sand fly biology and vector capacity for...
BACKGROUND
Microbial ecology of phlebotomine sand flies is not well understood although bacteria likely play an important role in the sand fly biology and vector capacity for Leishmania parasites. In this study, we assessed the significance of the microbial community of rabbit feces in oviposition and larval development of Lutzomyia longipalpis as well as bacterial colonization of the gut of freshly emerged flies.
METHODS
Sterile (by autoclaving) and non-sterile (control) rabbit feces were used in the two-choice assay to determine their oviposition attractiveness to sand fly females. Bacteria were identified by amplification and sequencing of the 16S rRNA gene with universal eubacterial primers. Sterile, control (non-sterile), and sterilized and inoculated rabbit feces were used to assess the significance of bacteria in L. longipalpis development. Newly emerged adult flies were surface-sterilized and screened for the bacterial population size and diversity by the culturing approach. The digestive tract of L4 sterile and control larvae was incubated with Phalloidin to visualize muscle tissues and DAPI to visualize nuclei.
RESULTS
Two-choice behavioural assays revealed a great preference of L. longipalpis to lay eggs on rabbit feces with an active complex bacterial community (control) (85.8 % of eggs) in comparison to that of sterile (autoclaved) rabbit feces (14.2 %). Bioassays demonstrated that L. longipalpis larvae can develop in sterile rabbit feces although development time to adult stage was greatly extended (47 days) and survival of larvae was significantly lower (77.8 %) compared to that of larvae developing in the control rabbit feces (32 days and 91.7 %). Larval survival on sterilized rabbit feces inoculated with the individual bacterial isolates originating from this substrate varied greatly depending on a bacterial strain. Rhizobium radiobacter supported larval development to adult stage into the greatest extent (39 days, 88.0 %) in contrast to that of Bacillus spp. (76 days, 36.0 %). From the complex natural bacterial community of rabbit feces, R. radiobacter survived pupation and colonized the newly emerged females most successfully (82.6 % of all bacteria cultured); however, only 25 % of females were positive for bacteria in the digestive tract upon emergence. Immunohistochemistry did not reveal any obvious differences in anatomy of the digestive tract between control and axenic larvae.
CONCLUSIONS
The bacterial community in the sand fly larval habitat affects oviposition and larval development although bacteria are not essential for successful development of L. longipalpis. Different bacteria contribute to larval development to various degrees and some, e.g. Rhizobium radiobacter, survive pupation and colonize the digestive tract of newly emerged females. With the establishment of the axenic rearing system, this study opens new venues to study the effect of bacteria on the gut epithelial immunity and vector competence of sand flies for Leishmania parasites with a goal to develop paratransgenic approaches for Leishmania control.
Topics: Animals; Bacteria; Behavior, Animal; Feces; Female; Gastrointestinal Tract; Larva; Oviposition; Psychodidae; RNA, Bacterial; RNA, Ribosomal, 16S; Rabbits
PubMed: 22827861
DOI: 10.1186/1756-3305-5-145 -
Journal of Vector Ecology : Journal of... Mar 2011This paper presents the results of an entomological survey in an endemic focus of cutaneous leishmaniasis in the Cukurova region of Turkey. A total of 8,927 specimens...
This paper presents the results of an entomological survey in an endemic focus of cutaneous leishmaniasis in the Cukurova region of Turkey. A total of 8,927 specimens belonging to eight Phlebotomus and two Sergentomyia species were captured with sticky papers and CDC light traps from 52 stations. Phlebotomus tobbi Adler, was found to be the most abundant species. Sand fly activity started in May and ended in October. Abundance was highest in August. According to the frequency distributions among certain temperature intervals the observed number of individuals was significantly different from the expected values between 22-24° C and 28-30° C. There was no significant correlation between the abundance of sand flies and altitude. However, sand fly species showed great aggregation at the 100-199 m and 200-299 m altitude intervals. The Shannon-Weinner index indicated no difference between the diversity and abundance of sand flies at different altitudes. Diversity and evenness reached maximum values at 500 m. Jaccard's coefficient indicated that similarity was the highest between 0-99 and 300-399, 0-99 and 500-599 and 100-199 and 200-299 m and lowest between 100-199 and 300-399 and 100-199 and 500-599 m.
Topics: Animals; Insect Vectors; Leishmaniasis, Cutaneous; Psychodidae; Seasons; Turkey
PubMed: 21366785
DOI: 10.1111/j.1948-7134.2011.00116.x -
The optimization of PpSP15 purification from salivary glands in Iranian wild (Diptera: Psychodidae).Journal of Vector Borne Diseases 2022Sand fly saliva contains proteins that modulate the host immune system and it plays an important role in both blood feeding and the outcome of Leishmania infections. The...
BACKGROUND & OBJECTIVES
Sand fly saliva contains proteins that modulate the host immune system and it plays an important role in both blood feeding and the outcome of Leishmania infections. The profile of the salivary proteins was examined and analyzed from an endemic focus of zoonotic cutaneous leishmaniasis by wild P. papatasi to find local and suitable antigens as potential proteins for developing Leishmania vaccine alongside the development of a new extraction technique.
METHODS
Specimens were caught from Bojnord, using funnel and CDC traps. Different methods of protein extraction were employed and a new technique was developed. The proteins were extracted from the salivary glands tissues with a lysis buffer. Purification was performed using RP-HPLC, with a linear gradient protocol from 0-60 % of acetonitrile. PpSP15 was characterized by SDS-PAGE.
RESULTS
The concentration of extracted protein content was 0.5 and 0.03 μg/μl in chemical and physical methods, respectively. PpSP15 was isolated at a weight of 15kDa in 80-85 min of run time. SDS-PAGE was able to characterize PpSP15. The crude extract of the chemical method, revealed 15 separated bands, ranging from 11-100 KDa. Tajima D index was positive.
INTERPRETATION & CONCLUSION
PpSP15 was characterized from Iranian specimens; it is a very highly hydrophobic protein of salivary glands among SP15- like proteins. The chemical method of extraction was found to be more effective than physical methods (P < 0.05). For developing a vaccine against leishmaniasis, depending on the location, choosing suitable proteins should be considered and an efficient extraction method should be used.
Topics: Animals; Iran; Leishmaniasis, Cutaneous; Phlebotomus; Psychodidae; Salivary Glands
PubMed: 35708406
DOI: 10.4103/0972-9062.331405 -
Parasites & Vectors Sep 2020Phlebotomine sand flies are a medically important group of insects that is responsible for the transmission of leishmaniasis. Surveillance plays a major role in vector...
BACKGROUND
Phlebotomine sand flies are a medically important group of insects that is responsible for the transmission of leishmaniasis. Surveillance plays a major role in vector control programmes through exploring species abundance, potential entomological risk and designing appropriate control measures. In field surveillance programmes of such nature, morphological identification of vector species is of paramount importance. However, in Sri Lanka, there is no published taxonomic key available for the identification of leishmaniasis vectors.
METHOD
Identification keys for both male and females of the sand flies recorded in Sri Lanka were developed using morphological features. Main identification features were compared with the original observation of specimens collected from surveys and the use of published literature. Photographic illustrations of morphological features are included with the intention of making the keys user-friendly for non-taxonomists.
RESULTS
A total of 22 sand fly species (Diptera: Psychodidae) of the genera Phlebotomus and Sergentomyia reported in Sri Lanka from 1910 to 2019 are included in the present work.
CONCLUSION
This simplified key, along with photographs taken from specimens would be beneficial to the health staff, entomologists and research staff who deal with leishmaniasis control programmes and vector-related studies.
Topics: Animals; Classification; Humans; Insect Vectors; Leishmaniasis; Phlebotomus; Psychodidae; Sri Lanka
PubMed: 32894177
DOI: 10.1186/s13071-020-04305-w -
PloS One 2017Visceral leishmaniasis (VL) also known as kala-azar is a growing health problem in Ethiopia with an estimated annual VL incidence between 3700 and 7400. The disease is...
BACKGROUND
Visceral leishmaniasis (VL) also known as kala-azar is a growing health problem in Ethiopia with an estimated annual VL incidence between 3700 and 7400. The disease is mainly endemic in northwestern parts of the country. The aim of the current study was to determine the sand fly fauna and ecology of Phlebotomus orientalis in two endemic and ecologically distinct areas of northwestern Ethiopia.
METHODS
Sand flies were collected using CDC light traps, sticky traps and pyrethrum spray catches from peri-domestic, mixed forest, farm field and indoor habitats from both Libo-Kemkem (May 2011-April 2012) and Metema (October 2012-September 2013) districts.
RESULTS
A total of 51,411 sand fly specimens were collected and identified (10,776 from highland and 40, 635 from the lowland areas). Seven species were found in the highland area: two Phlebotomus spp. (P. orientalis and P. rodhaini) and five Sergentomyia species. Whereas 19 species were found in the lowland area: six Phlebotomus (P. orientalis, P. rodhaini, P. bergeroti, P. duboscqi, P. papatasi and P. martini) and 13 Sergentomyia species. Of the Phlebotomus spp., P. orientalis was the predominant species in both the highland (99.9%) and lowland (93.7%) areas. Indoor collections using pyrethrum spray catches and sticky traps indicated that P. orientalis has a strong exophilic and exophagic behaviors in both districts. In both areas, this species showed seasonal occurrence and showing abundance during the dry months (March-May/June) of the year and increasing in numbers till the rain season, when numbers dropped dramatically. Mean density of P. orientalis in the two areas had positive and significant correlation with mean temperature in light trap collections (P<0.05). However, mean density of P. orientalis in the two areas in sticky trap collections had positive and insignificant association with the temperature (P>0.05). Regarding the rainfall pattern, density of P. orientalis had negative and statistically insignificant correlation (for light trap collections for both areas) and significant correlation (for sticky trap collections for lowland area).
CONCLUSIONS
The current study indicated the variation in sand fly fauna between the highland and lowland districts, wherein, P. orientalis was found to be the most abundant Phlebotomus species. The study also determined that P. orientalis exhibits distinct seasonality, where its abundance increases during the dry season and disappears when the rainy period starts in both study areas. This entomological observation on the bionomics of P. orientalis provides significant evidence for considering vector control or preventive measures in the areas studied.
Topics: Animals; Behavior, Animal; Ecology; Ecosystem; Female; Insect Vectors; Leishmaniasis, Visceral; Male; Psychodidae; Sex Ratio; Species Specificity
PubMed: 28384307
DOI: 10.1371/journal.pone.0175308