Examining the Relationship of Clinical and Laboratory Parameters With Infectiousness to Phlebotomus perniciosus and Its Potential Infectivity in Dogs With Overt Clinical Leishmaniasis

Infected dogs are considered the main domestic animal reservoirs for Leishmania infantum parasite. Infectiousness to competent phlebotomine vectors has been associated with many factors, the main being the severity of the disease exhibited by infected dogs. This study examines the relationship between different clinical parameters and the infectiousness to colonized Phlebotomus perniciosus sand flies having a blood meal on dogs. Data obtained in the present study come from an untreated group of Leishmania sick dogs submitted to xenodiagnosis for the evaluation of a spot on insecticide solution. Seventeen dogs were diagnosed as affected by leishmaniasis through clinical examination, immunofluorescence antibody test (IFAT) serology, and loop-mediated isothermal amplification (LAMP). The disease severity (clinical score) was staged by using a numeric value derived from eight clinical and parasitological parameters. Xenodiagnosis was performed on caged dogs exposed for 1.5 h to sand-fly bites. The following parameters related to sand flies were examined: blood feeding (% of blood engorged females), promastigote detection (% of promastigote-positive sand flies), promastigote burden, and the promastigote stage maturation (potential transmissibility rate). Statistical relationship between the clinical score and entomological parameters was investigated, as well as the possible correlation between each clinical and laboratory parameters and sand fly infection/infectivity. The severity of clinical score may influence the blood feeding by, and the probability of promastigote detection in, sand flies; skin lesions seem to be the main factor that influences the rate of blood feeding. Promastigote burden is related to IFAT titer, skin lesions, and clinical score. All entomological parameters are strongly related among them. This study confirms that both P. perniciosus infection and infectivity are influenced by a dog's clinical condition.

Download Full-text

Density assessment and reporting for Phlebotomus perniciosus and other sand fly species in periurban residential estates in Spain

Parasitology Research ◽

10.1007/s00436-021-07270-0 ◽

2021 ◽

Author(s):

C. Muñoz ◽

J. Risueño ◽

P. Pérez-Cutillas ◽

L. J. Bernal ◽

J. M. Ortiz ◽

...

Keyword(s):

Domestic Animal ◽

Sand Fly ◽

Canine Leishmaniasis ◽

Residential Areas ◽

Vector Ecology ◽

Phlebotomus Perniciosus ◽

Mediterranean Countries ◽

European Database ◽

History Of ◽

Density Assessment

AbstractGreen periurban residential areas in Mediterranean countries have flourished in the last decades and become foci for leishmaniasis. To remedy the absence of information on vector ecology in these environments, we examined phlebotomine sand fly distribution in 29 sites in Murcia City over a 3-year period, including the plots of 20 detached houses and nine non-urbanized sites nearby. We collected 5,066 specimens from five species using “sticky” interception and light attraction traps. The relative frequency of the main Leishmania infantum vector Phlebotomus perniciosus in these traps was 32% and 63%, respectively. Sand fly density was widely variable spatially and temporally and greatest in non-urbanized sites, particularly in caves and abandoned buildings close to domestic animal holdings. Phlebotomus perniciosus density in house plots was positively correlated with those in non-urbanized sites, greatest in larger properties with extensive vegetation and non-permanently lived, but not associated to dog presence or a history of canine leishmaniasis. Within house plots, sand fly density was highest in traps closest to walls. Furthermore, the study provides a guideline for insect density assessment and reporting and is envisioned as a building block towards the development of a pan-European database for robust investigation of environmental determinants of sand fly distribution.

Download Full-text

Diversity and Dynamics of Sand Flies (Diptera: Psychodidae) of Two Cutaneous Leishmaniasis Foci in the Fes-Boulemane Region of Northern Morocco

International Journal of Zoology ◽

10.1155/2015/497169 ◽

2015 ◽

Vol 2015 ◽

pp. 1-6 ◽

Cited By ~ 6

Author(s):

Fatima Zahra Talbi ◽

Chafika Faraj ◽

Fouad EL-Akhal ◽

Fatiha El Khayyat ◽

Driss Chenfour ◽

...

Keyword(s):

Cutaneous Leishmaniasis ◽

Statistical Tests ◽

Control Measures ◽

Sand Fly ◽

Sand Flies ◽

Phlebotomus Papatasi ◽

Phlebotomus Perniciosus ◽

Phlebotomus Sergenti ◽

Sergentomyia Minuta ◽

Two Peaks

Cutaneous leishmaniasis (CL) is an infectious disease caused by various species ofLeishmaniaand transmitted by several species of sand flies (Diptera: Psychodidae). In order to evaluate the risk of leishmaniasis transmission in Fes-Boulemane, an investigation was carried out in two localities, Aichoun and Bouasseme, during 2011. From January to December, 1120 specimens were collected in Aichoun comprising six species belonging to two genera:Phlebotomus sergenti(76.07%),Phlebotomus longicuspis(9.01%),Phlebotomus perniciosus(8.48%),Phlebotomus papatasi(4.82%),Sergentomyia minuta,andSergentomyia fallax. For Bouasseme, seven species were identified withPhlebotomus sergenti(60.39%) dominating, followed byPhlebotomus perniciosus(20%) andPhlebotomus longicuspis(12.15%). The remaining species,Phlebotomus papatasi,Phlebotomus ariasi,Sergentomyia minuta,andSergentomyia fallax,were less prevalent. The activity of sand flies in both localities is marked by the dominance ofPh. sergentiwith two peaks occurring in June and September. In order to obtain a better understanding of sand fly diversity among their species, results were analyzed by the ecological indices determinant: specific richness, the relative abundance, and Shannon-Weiner index (H′). Further studies of sand fly diversity should employ statistical tests and molecular analyses. This study can be useful in the implementation of appropriate future control measures.

Download Full-text

Response to thermal and infection stresses in an American vector of visceral leishmaniasis

10.1101/2020.11.23.373100 ◽

2020 ◽

Author(s):

Kelsilandia A. Martins ◽

Caroline S. Morais ◽

Susan J. Broughton ◽

Claudio R. Lazzari ◽

Paul A. Bates ◽

...

Keyword(s):

Heat Shock ◽

Body Temperature ◽

Visceral Leishmaniasis ◽

Heat Shock Proteins ◽

Blood Meal ◽

Blood Feeding ◽

The Body ◽

Sand Fly ◽

Sand Flies ◽

Shock Proteins

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.

Download Full-text

Insecticidal efficacy against Phlebotomus perniciosus in dogs treated orally with fluralaner in two different parallel-group, negative-control, random and masked trials

Parasites & Vectors ◽

10.1186/s13071-021-05128-z ◽

2022 ◽

Vol 15 (1) ◽

Author(s):

Gioia Bongiorno ◽

Leon Meyer ◽

Alec Evans ◽

Nouha Lekouch ◽

Padraig Doherty ◽

...

Keyword(s):

Negative Control ◽

Western Mediterranean ◽

Reservoir Host ◽

Sand Fly ◽

Control Group ◽

Sand Flies ◽

Phlebotomus Perniciosus ◽

Parallel Group ◽

Insecticidal Efficacy ◽

And Control

Abstract Background Dogs are the reservoir host of Leishmania infantum, the agent of zoonotic visceral leishmaniasis (VL), which is transmitted by the bite of phlebotomine sand flies. The sand fly Phlebotomus perniciosus is the main vector of zoonotic VL in the western Mediterranean region. Fluralaner has been shown to effectively kill this vector. The aim of this study was to evaluate the insecticidal efficacy of oral fluralaner in dogs bitten by P. perniciosus. Methods Two parallel-group, negative-controlled, randomized, masked laboratory trials with equivalent designs were performed in two different locations using two different pathogen-free laboratory-bred P. perniciosus strains for the challenge. In each trial, 12 purpose-bred beagles, initially ranked on natural attractiveness to sand flies, were randomly allocated to two groups (6 animals/group). Dogs in one group received fluralaner orally at the approved dose on day 0, and dogs in the control group were not treated. Each dog was subsequently exposed to an average of 70 unfed live sand fly females on days 1, 28, 56 and 84. Viability of blood-fed females was then evaluated for up to 96 h after exposure, and insecticidal efficacy was measured as the survival rate of flies fed on the fluralaner-treated dogs versus that of dogs in the control group. Significance was calculated for the proportion of live fed sand fly counts from treated versus control group dogs. Results Comparison of the survival proportions between treated and control groups showed that fluralaner insecticidal efficacy was highly significant in both trials (P < 0.001 or P < 0.01 in different assessments) through to day 56. In the first trial, efficacy reached 100% on days 1 and 28, and 99.1% on day 56; in the second trial, the insecticidal efficacy was 98.5, 100 and 85.9%, respectively on the same days. On day 84, efficacy was in the range of 53–57% (P < 0.05) in the first trial and 0% in the second trial. Conclusion A single oral fluralaner administration to dogs under laboratory conditions results in strong and reproducible insecticidal efficacy against P. perniciosus for at least 8 weeks. Graphical Abstract

Download Full-text

A Second Generation Leishmanization Vaccine with a Markerless Attenuated Leishmania major Strain using CRISPR gene editing

10.1101/2020.05.04.077115 ◽

2020 ◽

Author(s):

Wen Wei Zhang ◽

Subir Karmakar ◽

Sreenivas Gannavaram ◽

Ranadhir Dey ◽

Patrick Lypaczewski ◽

...

Keyword(s):

Second Generation ◽

Leishmania Major ◽

Parasite Burden ◽

Skin Lesions ◽

Genetically Engineered ◽

Sand Fly ◽

Sand Flies ◽

Host Protection ◽

Marker Free ◽

Immunocompromised Mice

AbstractLeishmaniasis is a debilitating and often fatal neglected tropical disease caused by Leishmania protozoa transmitted by infected sand flies. Vaccination through leishmanization with live Leishmania major has been used successfully but is no longer practiced because it resulted in unacceptable skin lesions. A second generation leishmanization is described here using a CRISPR genome edited L. major strain (LmCen-/-). Notably, LmCen-/- is the first genetically engineered gene deleted Leishmania strain that is antibiotic resistant marker free and does not have any off-target mutations. Mice immunized with LmCen-/- had virtually no visible lesions following challenge with L. major-infected sand flies while non-immunized animals developed large and progressive lesions with a 2-log fold higher parasite burden. LmCen-/- immunization showed protection and an immune response comparable to leishmanization. LmCen-/- is safe since it was unable to cause disease even in immunocompromised mice, induces robust host protection against vector sand fly challenge and because it is marker free, can be advanced to human vaccine trials.

Download Full-text

Exploring the influence of different habitats and their volatile chemistry in modulating sand fly population structure in a leishmaniasis endemic foci, Kenya

PLoS Neglected Tropical Diseases ◽

10.1371/journal.pntd.0009062 ◽

2021 ◽

Vol 15 (2) ◽

pp. e0009062

Author(s):

Iman B. Hassaballa ◽

Baldwyn Torto ◽

Catherine L. Sole ◽

David P. Tchouassi

Keyword(s):

Blood Feeding ◽

Sand Fly ◽

Spectrometric Analysis ◽

Cow Dung ◽

Sand Flies ◽

Cross Sectional Survey ◽

Public Health Importance ◽

Termite Mounds ◽

Cross Sectional ◽

Resting Sites

Phlebotomine sand flies transmit many viral protozoan and bacterial pathogens of public health importance. Knowledge of the ecologic factors influencing their distribution at local scale can provide insights into disease epidemiology and avenues for targeted control. Animal sheds, termite mounds and houses are important peri-domestic and domestic habitats utilized by different sand flies as resting or breeding habitats. However, our knowledge for selection of these habitats by sand flies remains poor. Here, we tested the hypothesis that these habitat types harbor different composition of sand fly species and differ in their volatile chemistry that could influence sand fly selection. To achieve this, we employed CDC light traps following a cross-sectional survey to investigate the distribution of sand flies in the three habitats in an endemic site for leishmaniasis in Kenya. The study was carried out during the dry season, when sand flies are optimally abundant in 2018 and 2020. Sand fly abundance did not vary between the habitats, but species-specific differences in abundance was evident. Measures of sand fly community structure (Shannon diversity and richness) were highest in animal shed, followed by termite mound and lowest inside human dwelling (house). This finding indicates broader attraction of both sexes of sand flies and females of varying physiological states to animal sheds potentially used as breeding or resting sites, but also as a signal for host presence for a blood meal. Furthermore, gas chromatography-mass spectrometric analysis of volatiles collected from represented substrates associated with these habitats viz: human foot odor on worn socks (houses indoors), cow dung (animal sheds) and termite mounds (enclosed vent), revealed a total of 47 volatile organic compounds. Of these, 26, 35 and 16 were detected in human socks, cow dung and enclosed termite vent, respectively. Of these volatiles, 1-octen-3-ol, 6-methyl-5-hepten-2-one, α-pinene, benzyl alcohol, m-cresol, p-cresol and decanal, previously known as attractants for sandflies and other blood-feeding insects, were common to the habitats. Our results suggest that habitat volatiles may contribute to the composition of sand flies and highlight their potential for use in monitoring sand fly populations.

Download Full-text

Quantitative and Qualitative Costs of Autogeny in Phlebotomus papatasi (Diptera: Psychodidae) Sand Flies

Journal of Medical Entomology ◽

10.1093/jme/tjz223 ◽

2019 ◽

Vol 57 (3) ◽

pp. 852-861 ◽

Cited By ~ 1

Author(s):

Tatsiana Shymanovich ◽

Nima Hajhashemi ◽

Gideon Wasserberg

Keyword(s):

Egg Production ◽

Larval Density ◽

Group Development ◽

Blood Feeding ◽

Development Rate ◽

Sand Fly ◽

Egg Mass ◽

Hatching Rate ◽

Sand Flies ◽

Larval Stages

Abstract Most sand flies and mosquitoes require a bloodmeal for egg production, but when blood-sources are scarce, some of them can reproduce without it, so called facultative autogeny. The evolution of autogenous reproduction is thought to involve a trade-off between the benefit of reproducing in the absence of bloodmeal hosts versus the quantitative cost of reduced fecundity and/or or qualitative effect on reduced offspring development and survivorship. We blood-fed (BF) some Phlebotomous papatasi (Scopoli) sand fly females on mice while keeping others (from the same cohort) not BF. We then compared the fecundity of BF and non-blood-fed (NBF) females and also evaluated their egg mass and hatching rate, larval development rate and survivorship, pupa mass and eclosion rates, and progeny fecundity. Among NBF females, only 55% became gravid and produced three times less mature oocytes than BF ones. Autogenous females laid 3.5 and 5.7 times fewer eggs in individual and multi-female bioassays, respectively. Egg mass and hatching rate were not affected by blood-feeding. Individual-larvae bioassays suggested reduced survival during larval stages in the autogenous group. In multi-larvae bioassays, overall and especially pupae survival was significantly reduced in the autogenous group. Development rate was slower and pupal mass was reduced in progeny from autogenous mothers. These effects were particularly apparent at high larval density. Mothers’ blood-feeding history did not affect daughter’s fecundity. Studies on the costs of autogeny provides insights on the evolution of blood feeding. Moreover, it also provides insights regarding potential implications of autogeny to the emergence of vector-borne diseases.

Download Full-text

Micro-CT visualization of a promastigote secretory gel (PSG) and parasite plug in the digestive tract of the sand fly Lutzomyia longipalpis infected with Leishmania mexicana

PLoS Neglected Tropical Diseases ◽

10.1371/journal.pntd.0009682 ◽

2021 ◽

Vol 15 (8) ◽

pp. e0009682

Author(s):

Martin J. R. Hall ◽

Debashis Ghosh ◽

Daniel Martín-Vega ◽

Brett Clark ◽

Innes Clatworthy ◽

...

Keyword(s):

Blood Meal ◽

Blood Feeding ◽

Sand Fly ◽

Laboratory Model ◽

Lutzomyia Longipalpis ◽

Sand Flies ◽

Leishmania Mexicana ◽

Micro Computed Tomography ◽

The Tropics ◽

The Impact

Leishmaniasis is a debilitating disease of the tropics, subtropics and southern Europe caused by Leishmania parasites that are transmitted during blood feeding by phlebotomine sand flies (Diptera: Psychodidae). Using non-invasive micro-computed tomography, we were able to visualize the impact of the laboratory model infection of Lutzomyia longipalpis with Leishmania mexicana and its response to a second blood meal. For the first time we were able to show in 3D the plug of promastigote secretory gel (PSG) and parasites in the distended midgut of whole infected sand flies and measure its volume in relation to that of the midgut. We were also able to measure the degree of opening of the stomodeal valve and demonstrate the extension of the PSG and parasites into the pharynx. Although our pilot study could only examine a few flies, it supports the hypothesis that a second, non-infected, blood meal enhances parasite transmission as we showed that the thoracic PSG-parasite plug in infected flies after a second blood meal was, on average, more than twice the volume of the plug in infected flies that did not have a second blood meal.

Download Full-text

Phlebotominae Fauna (Diptera: Psychodidae) and Molecular Detection of Leishmania (Kinetoplastida: Trypanosomatidae) in Urban Caves of Belo Horizonte, Minas Gerais, Brazil

Journal of Medical Entomology ◽

10.1093/jme/tjab156 ◽

2021 ◽

Author(s):

Paula Cavalcante Lamy Serra e Meira ◽

Bruna Lacerda Abreu ◽

Ana Paula Lusardo de Almeida Zenóbio ◽

Cristiani de Castilho Sanguinette ◽

Felipe Dutra Rêgo ◽

...

Keyword(s):

Urban Areas ◽

Molecular Detection ◽

Minas Gerais ◽

Sand Fly ◽

Leishmania Braziliensis ◽

Sand Flies ◽

Light Traps ◽

Endemic Focus ◽

Belo Horizonte ◽

The Relationship

Abstract Sand flies are often collected in urban areas, which has several implications for the risk of transmission of Leishmania Ross, 1903, to humans and other mammals. Given this scenario, we describe the sand fly fauna of caves and their surroundings in Mangabeiras Municipal Park (MMP) and Paredão Serra do Curral Park (PSCP), both located in the urban area of Belo Horizonte, Minas Gerais, Brazil, an endemic focus of visceral and cutaneous leishmaniasis. Collections were conducted monthly from November 2011 to October 2012, using CDC light traps exposed for two consecutive nights in four caves and their surroundings. Nonsystematized collections using Shannon traps and active searches were also performed around the caves. The presence of Leishmania DNA in collected female sand flies was evaluated by ITS1-PCR. A total of 857 sand flies representing fourteen species were collected in MMP, of which Evandromyia edwardsi (Mangabeira, 1941) was the most abundant. Leishmania amazonensis was detected in Brumptomyia nitzulescui (Costa Lima, 1932) and Ev. edwardsi, with the latter also having Leishmania braziliensis, Leishmania infantum, and Leishmania sp. A total of 228 sand flies representing four species were collected in PSCP, of which Sciopemyia microps (Mangabeira, 1942) was the most abundant. No females from PSCP were positive for Leishmania-DNA. Studies aimed at describing sand fly faunas of cave environments and detecting Leishmania are essential to understanding the relationship between these insects and this ecotope and assessing and monitoring areas that may pose risks to the health of visitors and employees.

Download Full-text