scholarly journals The Diversity of Midgut Bacteria among Wild-Caught Phlebotomus argentipes (Psychodidae: Phlebotominae), the Vector of Leishmaniasis in Sri Lanka

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Nayana Gunathilaka ◽  
Hirunika Perera ◽  
Tharaka Wijerathna ◽  
Wasana Rodrigo ◽  
N. D. A. D. Wijegunawardana
Keyword(s):  
Sri Lanka ◽  
Medical Officer ◽  
Sand Fly ◽  
Parasite Development ◽  
Morphological Identification ◽  
Potential Candidate ◽  
Sand Flies ◽  
Phlebotomus Argentipes ◽  
Antileishmanial Activities ◽  
Potential Use

Phlebotomus argentipes is the main suspected vector for leishmaniasis in Sri Lanka. Investigations on the presence of aerobic bacteria in the gut of sand flies which evidence a potential approach to control leishmaniasis transmission through a paratransgenic strategy are still not available for the local sand fly populations. Field-caught unfed female sand flies collected from three selected Medical Officer of Health (MOH) areas (Polpithigama, Maho, and Galgamuwa) in Kurunegala District, Sri Lanka from August to December 2018 were used. Prokaryotic 16S ribosomal RNA partial gene was amplified and sequenced. Morphological identification revealed the presence of only one sand fly species, P. argentipes (n=1,969). A total of 20 organisms belonging to two phyla (Proteobactericea and Furmicutes) were detected within the gut microbial community of the studied sand fly specimens. This study documents the first-ever observation of Rhizobium sp. in the midgut of P. argentipes. The presence of Bacillus megaterium, which is considered as a nonpathogenic bacterium with potential use for paratransgenic manipulation of P. argentipes suggest that it may be used as a delivery vehicle to block the vectorial transmission of Leishmania parasites. In addition, Serratia marcescens may be used as a potential candidate to block the parasite development in sand fly vectors since it has evidenced antileishmanial activities in previous investigations. Hence, further studies are required to gain full insight into the potential use of this bacterium in the control of Leishmania parasites through paratransgenesis.

scholarly journals Morphological identification keys for adults of sand flies (Diptera: Psychodidae) in Sri Lanka

2020 ◽  
Vol 13 (1) ◽  
Author(s):  
Tharaka Wijerathna ◽  
Nayana Gunathilaka
Keyword(s):  
Sri Lanka ◽  
Species Abundance ◽  
Morphological Features ◽  
Control Measures ◽  
Sand Fly ◽  
Health Staff ◽  
Morphological Identification ◽  
Sand Flies ◽  
Identification Keys ◽  
Control Programmes

Abstract 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.

scholarly journals Genetic diversity and population structure of Phlebotomus argentipes: Vector of Leishmania donovani in Sri Lanka

PLoS ONE ◽  
2021 ◽  
Vol 16 (9) ◽  
pp. e0256819
Author(s):  
Dulani Ruwanika K. Pathirage ◽  
Thilini C. Weeraratne ◽  
Sanath C. Senanayake ◽  
S. H. P. Parakrama Karunaratne ◽  
Nadira D. Karunaweera
Keyword(s):  
Gene Flow ◽  
Sri Lanka ◽  
Population Genetic ◽  
Leishmania Donovani ◽  
Sand Fly ◽  
Sand Flies ◽  
Phlebotomus Argentipes ◽  
Study Sites ◽  
Sand Fly Vectors ◽  
Cox 1

Phlebotomus argentipes is the vector of Leishmania donovani which causes the disease leishmaniasis, a neglected tropical disease and a growing health problem in Sri Lanka. A proper understanding of the population genetic structure of sand fly vectors is considered important prior to planning and implementation of a successful vector control program. Thus, the present study was conducted to determine the population genetic structure of sand fly vectors in Sri Lanka. Two mitochondrial genes namely Cytochrome c oxidase subunit 1 (Cox 1) and Cytochrome b (Cytb), and the internal transcribed spacer 2 (ITS2) region from the nuclear ribosomal DNA were used for molecular characterization. Analyses included maximum likelihood method, network analysis and DNA polymorphisms. The outcome revealed unique sequences of all genomic regions studied except the cox 1 gene had a relationship with sand flies isolated previously from Sri Lanka, India and Israel and cytb gene of 4 sand flies that aligned with those isolated earlier from Sri Lanka and 3 from Madagascar. Furthermore, cox 1 gene and ITS 2 region analyses based on FST values indicated a possible gene flow between the study sites whereas cytb gene analysis favoured the existence of genetically distinct populations of P. argentipes in each of the study sites. Poor population differentiation of P. argentipes, a possible consequence of a gene flow, is indeed of concern due to the risk imposed by promoting the spread of functionally important phenotypes such as insecticide resistance across the country, making future vector control efforts challenging.

Molecular and biochemical characterization of a sand fly population from Sri Lanka: evidence for insecticide resistance due to altered esterases and insensitive acetylcholinesterase

2005 ◽  
Vol 95 (4) ◽  
pp. 371-380 ◽  
Author(s):  
S.N. Surendran ◽  
S.H.P.P. Karunaratne ◽  
Z. Adamsn ◽  
J. Hemingway ◽  
N.J. Hawkes
Keyword(s):  
Sri Lanka ◽  
Insecticide Resistance ◽  
Biochemical Characterization ◽  
Preliminary Evidence ◽  
Resistance Mechanisms ◽  
Sand Fly ◽  
Cross Resistance ◽  
Cytochrome P450 Monooxygenases ◽  
Sand Flies

AbstractWith an increasing incidence of cutaneous leishmaniasis in Sri Lanka, particularly in northern provinces, insecticide-mediated vector control is under consideration. Optimizing such a strategy requires the characterization of sand fly populations in target areas with regard to species composition and extant resistance, among other parameters. Sand flies were collected by human bait and cattle-baited net traps on Delft Island, used as an illegal transit location by many refugees returning to the north of Sri Lanka from southern India where leishmaniasis is endemic. For species identification, genomic DNA was extracted and a fragment of the ribosomal 18S gene amplified. The sequence from all flies analysed matched that of Phlebotomus argentipes Annandale & Brunetti, the primary vector in India and the most likely vector in Sri Lanka. Independent morphological analysis also identified P. argentipes. To establish the current susceptibility status of vector species, data were obtained at the biochemical level, from which potential cross-resistance to alternative insecticides can be predicted. The Delft Island collection was assayed for the activities of four enzyme systems involved in insecticide resistance (acetylcholinesterase, non-specific carboxylesterases, glutathione-S-transferases and cytochrome p450 monooxygenases), establishing baselines against which subsequent collections can be evaluated. There was preliminary evidence for elevated esterases and altered acetylcholinesterase in this population, the first report of these resistance mechanisms in sand flies to our knowledge, which probably arose from the malathion-based spraying regimes of the Anti-Malarial Campaign.

scholarly journals Understanding Behavioural Temperament of Phlebotomus argentipes Under the Influence of DDT-IRS Versus SP-IRS for Scoping New Approaches for Maximum Control Over the VL-Vector Population in Bihar

2019 ◽  
pp. 1-11
Author(s):  
Vijay Kumar ◽  
Aarti Rama ◽  
Rakesh Mandal ◽  
Pradeep Das
Keyword(s):  
Vector Control ◽  
Light Trap ◽  
Maintenance Phase ◽  
Chemical Constituent ◽  
Sand Fly ◽  
Successful Implementation ◽  
Sand Flies ◽  
Phlebotomus Argentipes ◽  
Grass Root Level ◽  
The Impact

Background: After the decades of Dichlorodiphenyltrichloroethane (DDT) use, Phlebotomus argentipes reportedly developed resistance against it affecting every aspect of vector control at grass-root level. Although DDT based Indoor Residual Spray (IRS) has been replaced with Alphacypermethrine-a Synthetic Pyrethroid (SP) based insecticide, since 2016 but its successful implementation at the Visceral Leishmaniasis (VL) endemic regime of Bihar doesn’t cause much effect upon VL vector density. Furthermore, the outcomes of existing operational research works, it had been observed that VL vectors are continuously changing its behavior under the pressure of insecticides. Methods: For validating the hypothesis, present study has been carried out at Vaishali and Patna being highly and semi-endemic sites respectively for quantifying the oriental behavior among VL vectors persuaded by the IRS and enforce them to remain alive and get trapped in light trap even after changed chemical composition of IRS i.e., SP-IRS from routine DDT-IRS. Results: Following results, a significant reduction in sand fly density (i.e., 33.09% and 29.16%) was observed for outdoor and indoor caught sand flies, collected with light trap and aspirator respectively. Significant higher no. of sand fly collection in terms of per light traps per night was recorded from the outdoor sites than those from indoor habitat for each village of Vaishali and Saran district of Bihar. Higher no. of male sand flies than to that of female ones were collected from outdoor sites and only unfed female sand flies (i.e., 100%) were caught following SP-IRS from each study villages of Vaishali and Saran districts of Bihar. Conclusions: The results of higher no. of sand flies collection from the outdoor sites as compared with the indoor habitat validate the hypothesis of gradual shifting of habitat of VL vectors from endophilic to exophilic which is undoubtedly followed due to the fact of developed resistance among them against chemical constituent of IRS. Results  provide very useful information about the sand fly dynamics under the impact of IRS and accordingly, advocates the combined approach of IRS along with insecticidal fogging together at a same time that could be an effective dividend for maximum VL vector control along for negotiating VL cases at par for longer duration during the maintenance phase at the VL foci.

Phlebotomine sand flies (Psychodidae: Diptera) of Sri Lanka: a review on diversity, biology and bionomics

2019 ◽  
Vol 11 (2) ◽  
pp. 41-58 ◽  
Author(s):  
THARAKA WIJERATHNA ◽  
NAYANA GUNATHILAKA
Keyword(s):  
Sri Lanka ◽  
Sand Fly ◽  
Complete List ◽  
Sand Flies ◽  
Local Distribution ◽  
Phlebotomine Sand Flies ◽  
The World ◽  
Global And Local

Phlebotomine sand flies are medically important insects widespread throughout the world and responsible for the transmission of several diseases to humans and other animals including leishmaniasis and sand fly fever. In Sri Lanka, a total of 22 species of sand flies belonging to two genera, namely: Phlebotomus and Sergentomyia, have been recorded with 6 and 16 species, respectively. The current study reports a complete list of the species of sand flies reported from Sri Lanka with a review on global and local distribution, biology and bionomics of each species as per published literature up to June 2018. Keywords: Sand fly, distribution, Psychodidae, Phlebotominae

scholarly journals Integrative Approach to Phlebotomus mascittii Grassi, 1908: First Record in Vienna with New Morphological and Molecular Insights

Pathogens ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 1032
Author(s):  
Edwin Kniha ◽  
Vít Dvořák ◽  
Petr Halada ◽  
Markus Milchram ◽  
Adelheid G. Obwaller ◽  
...  
Keyword(s):  
First Record ◽  
Protein Profiling ◽  
Sand Fly ◽  
Integrative Approach ◽  
Marker Genes ◽  
Morphological Identification ◽  
Sand Flies ◽  
Maldi Tof Ms ◽  
Maldi Tof ◽  
Tof Ms

Sand flies (Diptera: Psychodidae: Phlebotominae) are blood-feeding insects that transmit the protozoan parasites Leishmania spp. and various arthropod-borne (arbo) viruses. While in Mediterranean parts of Europe the sand fly fauna is diverse, in Central European countries including Austria mainly Phlebotomus mascittii is found, an assumed but unproven vector of Leishmania infantum. To update the currently understudied sand fly distribution in Austria, a sand fly survey was performed and other entomological catches were screened for sand flies. Seven new trapping locations of Ph. mascittii are reported including the first record in Vienna, representing also one of the first findings of this species in a city. Morphological identification, supported by fluorescence microscopy, was confirmed by two molecular approaches, including sequencing and matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS) protein profiling. Sand fly occurrence and activity were evaluated based on surveyed locations, habitat requirements and climatic parameters. Moreover, a first comparison of European Ph. mascittii populations was made by two marker genes, cytochrome c oxidase subunit 1 (COI), and cytochrome b (cytb), as well as MALDI-TOF mass spectra. Our study provides new important records of Ph. mascittii in Austria and valuable data for prospective entomological surveys. MALDI-TOF MS protein profiling was shown to be a reliable tool for differentiation between sand fly species. Rising temperatures and globalization demand for regular entomological surveys to monitor changes in species distribution and composition. This is also important with respect to the possible vector competence of Ph. mascittii.

scholarly journals Binding of Leishmania infantum Lipophosphoglycan to the Midgut Is Not Sufficient To Define Vector Competence in Lutzomyia longipalpis Sand Flies

mSphere ◽  
2020 ◽  
Vol 5 (5) ◽  
Author(s):  
Iliano V. Coutinho-Abreu ◽  
James Oristian ◽  
Waldionê de Castro ◽  
Timothy R. Wilson ◽  
Claudio Meneses ◽  
...  
Keyword(s):  
Leishmania Infantum ◽  
Vector Competence ◽  
Sand Fly ◽  
Parasite Development ◽  
Lutzomyia Longipalpis ◽  
Sand Flies ◽  
Content Type ◽  
Survival And Development ◽  
Blood Meal Digestion ◽  
Insect Gut

It is well established that the presence of LPG is sufficient to define the vector competence of restrictive sand fly vectors with respect to Leishmania parasites. However, the permissiveness of other sand flies with respect to multiple Leishmania species suggests that other factors might define vector competence for these vectors. In this study, we investigated the underpinnings of Leishmania infantum survival and development in its natural vector, Lutzomyia longipalpis. We found that LPG-mediated midgut binding persists in late-stage parasites. This observation is of relevance for the understanding of vector-parasite molecular interactions and suggests that only a subset of infective metacyclic-stage parasites (metacyclics) lose their ability to attach to the midgut, with implications for parasite transmission dynamics. However, our data also demonstrate that LPG is not a determining factor in Leishmania infantum retention in the midgut of Lutzomyia longipalpis, a permissive vector. Rather, LPG appears to be more important in protecting some parasite strains from the toxic environment generated during blood meal digestion in the insect gut. Thus, the relevance of LPG in parasite development in permissive vectors appears to be a complex issue and should be investigated on a strain-specific basis.

scholarly journals Identification of Sand Flies (Diptera: Psychodidae) Collected from Cutaneous Leishmaniasis Endemic Focus in the Ho Municipality, Ghana

2020 ◽  
Vol 10 (1) ◽  
pp. 33-44
Author(s):  
Edna Dzifa Doe ◽  
Godwin Kwakye-Nuako ◽  
Seth Offei Addo ◽  
Alexander Egyir-Yawson
Keyword(s):  
Cutaneous Leishmaniasis ◽  
Sand Fly ◽  
Coi Gene ◽  
Morphological Identification ◽  
Correct Identification ◽  
Sand Flies ◽  
Oxidase Gene ◽  
Infected Female ◽  
Molecular Weights ◽  
Endemic Focus

Leishmaniasis, is a vector-borne disease transmitted to humans through the bite of infected female sand flies. Active and continuous monitoring of the sand fly is an important aspect of disease control. Thus, the correct identification of its vectors is paramount in this regard. Objective: The study was conducted to morphologically and molecularly identify female sand fly species in a cutaneous leishmaniasis endemic focus collected in three villages in the Ho Municipality of the Volta region based on taxonomic keys. CDC light traps and sticky paper traps was used for the collection of the sand flies. The morphologically identified sand flies was molecularly confirmed by running PCR with the mitochondrial cytochrome c oxidase gene subunit I (COI) primers and DNA sequenced. A total of 537 sand flies was collected, made up of 363 females and 174 males.  Eleven different species of sand flies was morphologically identified – one Phlebotomus species and ten Sergentomyia species. The PCR amplified products showed bands of molecular weights 658 base pairs for the primers. The molecular identification using the 658-bp fragment of the (COI) gene was congruent with the morphological identification.

scholarly journals Binding of Leishmania infantum LPG to the midgut is not sufficient to define vector competence in Lutzomyia longipalpis sand flies

2020 ◽  
Author(s):  
Iliano V. Coutinho-Abreu ◽  
James Oristian ◽  
Waldionê de Castro ◽  
Timothy R. Wilson ◽  
Claudio Meneses ◽  
...  
Keyword(s):  
Late Stage ◽  
Leishmania Infantum ◽  
Vector Competence ◽  
Sand Fly ◽  
Parasite Development ◽  
Lutzomyia Longipalpis ◽  
Sand Flies ◽  
Survival And Development ◽  
Sand Fly Vectors

AbstractThe major surface lipophosphoglycan (LPG) of Leishmania parasites is critical to vector competence in restrictive sand fly vectors by mediating Leishmania attachment to the midgut epithelium, considered essential to parasite survival and development. However, the relevance of LPG for sand flies that harbor multiple species of Leishmania remains elusive. We tested binding of Leishmania infantum wild type (WT), LPG-defective (Δlpg1 mutants) and add-back lines (Δlpg1 + LPG1) to sand fly midguts in vitro and their survival in Lutzomyia longipalpis sand flies in vivo. Le. infantum WT parasites attached to the Lu. longipalpis midgut in vitro with late-stage parasites binding to midguts in significantly higher numbers compared to early-stage stage promastigotes. Δlpg1 mutants did not bind to Lu. longipalpis midguts, and this was rescued in the Δlpg1 + LPG1 lines, indicating that midgut binding is mediated by LPG. When Lu. longipalpis sand flies were infected with either Le. infantum WT, Δlpg1, or Δlpg1 + LPG1 of the BH46 or BA262 strains, the BH46 Δlpg1 mutant, but not the BA262 Δlpg1 mutant, survived and grew to similar numbers as the WT and Δlpg1 + LPG1 lines. Exposure of BH46 and BA262 Δlpg1 mutants to blood engorged midgut extracts led to the mortality of the BA262 Δlpg1 but not the BH46 Δlpg1 parasites. These findings suggest that Le. infantum LPG protects parasites on a strain-specific basis early in infection, likely against toxic components of blood digestion, however, it is not necessary to prevent Le. infantum evacuation along with the feces in the permissive vector Lu. longipalpis.IMPORTANCEIt is well established that LPG is sufficient to define the vector competence of restrictive sand fly vectors to Leishmania parasites. However, the permissiveness of other sand flies to multiple Leishmania species suggests that other factors might define vector competence for these vectors. In this study, we investigated the underpinnings of Leishmania infantum survival and development in its natural vector Lutzomyia longipalpis. We found out that LPG-mediated midgut binding persists in late-stage parasites. This observation is paradigm-changing and suggests that only a subset of infective metacyclics lose their ability to attach to the midgut with implications for parasite transmission dynamics. However, our data also demonstrate that LPG is not a determining factor in Leishmania infantum retention in the midgut of Lutzomyia longipalpis, a permissive vector. Rather, LPG appears to be more important in protecting some parasite strains from the toxic environment generated during blood meal digestion in the insect gut. Thus, the relevance of LPG in parasite development in permissive vectors appears to be complex and should be investigated on a strain-specific basis.

scholarly journals Epidemiology of cutaneous leishmaniasis in a newly emerging focus in Gampaha district, Western province of Sri Lanka

2020 ◽  
Author(s):  
Chandana Harendra Mallawarachchi ◽  
Nilmini T. G. A. N Chandrasena ◽  
Tharaka Wijerathna ◽  
Rasika C.P.D. Dalpadado ◽  
Maleesha S.M.N.S. Mallawarachchi ◽  
...  
Keyword(s):  
Sri Lanka ◽  
Cutaneous Leishmaniasis ◽  
Negative Impact ◽  
Life Quality ◽  
Medical Officer ◽  
Sand Fly ◽  
Validated Questionnaire ◽  
The Mean ◽  
Study Participants

Abstract Background Cutaneous leishmaniasis (CL) appears to be spreading to previously non-endemic regions of Sri Lanka. The aim of this study was to describe a newly emerging focus of CL in the district of Gampaha, in Western Sri Lanka. Methods A case based descriptive study was carried out from January 2018 to April 2019 in the Mirigama Medical Officer of Health (MOH) area, which reported the highest number of CL cases in Gampaha District. Laboratory confirmed cases were traced and socio-demographic and clinical data were collected via a validated questionnaire and clinic records respectively. The quality of life (QOL) of study participants was measured using the Dermatology Life Quality Index (DLQI). Global Positioning System (GPS) coordinates of patient residences were recorded using handheld GPS receivers. Sand-flies were collected from four selected sites, using Indoor Hand Collection (IHC) (162 units) and Cattle Baited Net Traps (CBNT) (n=3) and a battery-operated aspirator. Results Of 73 patients identified in this study, 58.9% were males, with a mean age of 43.6 years (SD 20.1). The lesions included nodules (52.05%) and ulcers (47.9%). Single lesions were seen in 69.86%, while 30.1% had multiple. Except for one mucosal lesion, all others were on skin. Treatment varied from sodium stibogluconate (SSG) + cryotherapy (46.57%), SSG (45.2%) and cryotherapy (8.2%). Patients with multiple lesions were more likely to be treated with combined SSG + cryotherapy (p< 0.05). The mean DLQI score was 8.14 (SD=7). Most patients engaged in outdoor activities that exposed them to the risk of sand-fly bites Workplaces of 81.1% (27/33) were located within the district. Housing conditions of study participants were of moderate (59%), good (35.6%) and poor (5%) quality. Four households reported multiple cases. Spatial distribution of cases indicated notable clustering in seven adjacently located Public Health Inspector (PHI) areas. Phlebotomus argentipes was detected in all CBNTs and 35.28% of IHC units surveyed. Conclusions CL is emerging in Gamapha district with Mirigama MOH area being the epicentre of infection. The disease had a moderately negative impact on QOL of patients. Minimal migration of cases, clustering of cases within households and in the locality indicates local transmission with P. argentipes as the probable vector.

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