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1.
J Insect Sci ; 22(2)2022 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-35271719

RESUMO

Lutzomyia longipalpis (Lutz & Neiva, 1912) females have been intensively studied regarding the regulation of midgut pH. The mechanisms involved in pH regulation are complex, and some aspects remain to be clarified. Here, we investigated the role of the Na+/K+-ATPase pump as an electrochemical potential generator and its modulation by the second messenger cAMP in the midgut of female L. longipalpis. Our results suggest that not only may Na+/K+-ATPase be the main generator of an electrochemical potential across membranes in the midgut of female L. longipalpis, but also its activity is positively regulated by cAMP. cAMP-mediated Na+/K+-ATPase pump activity might be necessary to maintain the transport of the nutrients produced during blood digestion.


Assuntos
Psychodidae , Adenosina Trifosfatases , Animais , Sistema Digestório , Feminino , Psychodidae/fisiologia
2.
PLoS Negl Trop Dis ; 15(12): e0009942, 2021 12.
Artigo em Inglês | MEDLINE | ID: mdl-34928947

RESUMO

BACKGROUND: Secondary symbionts of insects include a range of bacteria and fungi that perform various functional roles on their hosts, such as fitness, tolerance to heat stress, susceptibility to insecticides and effects on reproduction. These endosymbionts could have the potential to shape microbial communites and high potential to develop strategies for mosquito-borne disease control. METHODOLOGY/PRINCIPAL FINDINGS: The relative frequency and molecular phylogeny of Wolbachia, Microsporidia and Cardinium were determined of phlebotomine sand flies and mosquitoes in two regions from Colombia. Illumina Miseq using the 16S rRNA gene as a biomarker was conducted to examine the microbiota. Different percentages of natural infection by Wolbachia, Cardinium, and Microsporidia in phlebotomines and mosquitoes were detected. Phylogenetic analysis of Wolbachia shows putative new strains of Lutzomyia gomezi (wLgom), Brumptomyia hamata (wBrham), and a putative new group associated with Culex nigripalpus (Cnig) from the Andean region, located in Supergroup A and Supergroup B, respectively. The sequences of Microsporidia were obtained of Pi. pia and Cx. nigripalpus, which are located on phylogeny in the IV clade (terrestrial origin). The Cardinium of Tr. triramula and Ps. shannoni were located in group C next to Culicoides sequences while Cardinium of Mi. cayennensis formed two putative new subgroups of Cardinium in group A. In total were obtained 550 bacterial amplicon sequence variants (ASVs) and 189 taxa to the genus level. The microbiota profiles of Sand flies and mosquitoes showed mainly at the phylum level to Proteobacteria (67.6%), Firmicutes (17.9%) and Actinobacteria (7.4%). High percentages of relative abundance for Wolbachia (30%-83%) in Lu. gomezi, Ev. dubitans, Mi. micropyga, Br. hamata, and Cx. nigripalpus were found. ASVs assigned as Microsporidia were found in greater abundance in Pi. pia (23%) and Cx. nigripalpus (11%). An important finding is the detection of Rickettsia in Pi. pia (58,8%) and Bartonella sp. in Cx. nigripalpus. CONCLUSIONS/SIGNIFICANCE: We found that Wolbachia infection significantly decreased the alpha diversity and negatively impacts the number of taxa on sand flies and Culex nigripalpus. The Principal Coordinate Analysis (PCoA) is consistent, which showed statistically significant differences (PERMANOVA, F = 2.4744; R2 = 0.18363; p-value = 0.007) between the microbiota of sand flies and mosquitoes depending on its origin, host and possibly for the abundance of some endosymbionts (Wolbachia, Rickettsia).


Assuntos
Bacteroidetes/isolamento & purificação , Culex/microbiologia , Microbiota , Microsporídios/isolamento & purificação , Filogenia , Psychodidae/microbiologia , Wolbachia/isolamento & purificação , Animais , Bacteroidetes/classificação , Bacteroidetes/genética , Bacteroidetes/fisiologia , Biodiversidade , Colômbia , Culex/fisiologia , Microsporídios/classificação , Microsporídios/genética , Microsporídios/fisiologia , Psychodidae/fisiologia , Simbiose , Wolbachia/classificação , Wolbachia/genética , Wolbachia/fisiologia
3.
PLoS Negl Trop Dis ; 15(10): e0009366, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34613967

RESUMO

BACKGROUND: Dogs are the primary reservoir for human visceral leishmaniasis due to Leishmania infantum. Phlebotomine sand flies maintain zoonotic transmission of parasites between dogs and humans. A subset of dogs is infected transplacentally during gestation, but at what stage of the clinical spectrum vertically infected dogs contribute to the infected sand fly pool is unknown. METHODOLOGY/PRINCIPAL FINDINGS: We examined infectiousness of dogs vertically infected with L. infantum from multiple clinical states to the vector Lutzomyia longipalpis using xenodiagnosis and found that vertically infected dogs were infectious to sand flies at differing rates. Dogs with mild to moderate disease showed significantly higher transmission to the vector than dogs with subclinical or severe disease. We documented a substantial parasite burden in the skin of vertically infected dogs by RT-qPCR, despite these dogs not having received intradermal parasites via sand flies. There was a highly significant correlation between skin parasite burden at the feeding site and sand fly parasite uptake. This suggests dogs with high skin parasite burden contribute the most to the infected sand fly pool. Although skin parasite load and parasitemia correlated with one another, the average parasite number detected in skin was significantly higher compared to blood in matched subjects. Thus, dermal resident parasites were infectious to sand flies from dogs without detectable parasitemia. CONCLUSIONS/SIGNIFICANCE: Together, our data implicate skin parasite burden and earlier clinical status as stronger indicators of outward transmission potential than blood parasite burden. Our studies of a population of dogs without vector transmission highlights the need to consider canine vertical transmission in surveillance and prevention strategies.


Assuntos
Doenças do Cão/diagnóstico , Leishmania infantum/fisiologia , Leishmaniose Visceral/veterinária , Pele/parasitologia , Animais , Doenças do Cão/parasitologia , Doenças do Cão/transmissão , Cães , Feminino , Transmissão Vertical de Doenças Infecciosas , Insetos Vetores/parasitologia , Insetos Vetores/fisiologia , Leishmania infantum/genética , Leishmania infantum/isolamento & purificação , Leishmaniose Visceral/diagnóstico , Leishmaniose Visceral/parasitologia , Leishmaniose Visceral/transmissão , Masculino , Carga Parasitária , Placenta/parasitologia , Gravidez , Psychodidae/parasitologia , Psychodidae/fisiologia , Tropismo , Xenodiagnóstico
4.
PLoS One ; 16(10): e0257043, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34644289

RESUMO

The present study aimed to check the sand flies' fauna on the municipality of Lassance, Minas Gerais, Brazil and detect the presence of Leishmania DNA on the female captured and determine the risk areas of the municipality. Sand flies were collected monthly from May 2018 to April 2019 using automatic light traps for 3 consecutive nights. Eight houses were selected as sample points due its previous reports of tegumentary leishmaniasis and/or canine leishmaniasis. The sand fly's fauna found on the present study it's represented by several medical importance species and the most abundant species found were Lutzomyia longipalpis (77.09%) and Nyssomyia intermedia (10.06%). Leishmania infantum DNA was detected in a pool of Lu. longipalpis resulting on a 2.81% of infection rate. By the frequency of the two most abundant species on this study, we developed a risk area map and it draws attention to sample point 6 due to disparate abundance of sand flies at this site (81.81%). Statistical overview shows Lu. longipalpis as dominant species and, still, Non-Metric Multidimensional Scaling analysis reveal high similarity on fauna's diversity on the study area. Our findings suggest that the diversity of sand flies from the municipality of Lassance may promote the circulation of Leishmania infantum parasites putting in risk the habitants and other mammal's species. Still, our study reinforces the necessity of specific studies focused on breed sites of phlebotomine and its' ecology to expand the knowledge about the behaviour of this group of insects applying directly to leishmaniases' epidemiology.


Assuntos
Insetos Vetores/parasitologia , Leishmania infantum/isolamento & purificação , Leishmaniose/transmissão , Psychodidae/parasitologia , Animais , Brasil/epidemiologia , Cidades/epidemiologia , DNA de Protozoário/genética , DNA de Protozoário/isolamento & purificação , Cães , Feminino , Humanos , Insetos Vetores/fisiologia , Leishmania infantum/genética , Leishmaniose/epidemiologia , Leishmaniose/veterinária , Psychodidae/fisiologia
5.
PLoS Negl Trop Dis ; 15(8): e0009676, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-34411102

RESUMO

The scarce information about breeding sites of phlebotomines limits our understanding of the epidemiology of tegumentary leishmaniasis. Identifying the breeding sites and seasons of immature stages of these vectors is essential to propose prevention and control strategies different from those targeting the adult stage. Here we identified the rural breeding environments of immature stages of Ny. whitmani, vector species of Leishmania braziliensis in the north of Misiones province, Argentina; then we determined and compared the environmental and structural characteristics of those sites. We also identified the season of greatest emergence and its relationship with adult abundance. During a first collection period, between 28 and 48 emergence traps were set continuously for 16 months in six environments of the farm peridomicile and domicile: below house, chicken shed, experimental chicken shed, forest edge, pigsty and under fruit tree. Traps were checked and rotated every 40 nights. A total of 146 newly emerged individuals were collected (93.8% of them were Ny. whitmani), totaling an effort of 23,040 emergence trap-nights. The most productive environments were chicken shed and below house, and the greatest emergence was recorded in spring and summer. During a second collection period, emergence traps and light traps for adult capture were placed in the chicken shed and below house environments of eight farms. Emergence traps were active continuously during spring, summer, and early autumn. Environmental and structural characteristics of each environment were recorded. A total of 84 newly emerged phlebotomines (92.9% Ny. whitmani; 72,144 emergence trap-nights) and 13,993 adult phlebotomines (147 light trap-nights) were recorded in the chicken shed and below house environments. A positive correlation was also observed between trap success of newly emerged phlebotomines and of adults after 120 days. A high spatial variability was observed in the emergence of Ny. whitmani, with the number of newly emerged individuals being highest in soils of chicken sheds with the highest number of chickens and closest to forest edge. Moreover, below house was found to be as important as chicken sheds as breeding sites of Ny. whitmani. Management of the number of chickens in sheds, soil moisture and pH, and the decision of where to localize the chicken sheds in relation to the houses and the forest edge, might contribute to reduce the risk of human vector exposure and transmission of Leishmania.


Assuntos
Insetos Vetores/fisiologia , Leishmaniose/epidemiologia , Psychodidae/fisiologia , Animais , Argentina/epidemiologia , Cruzamento , Galinhas , Feminino , Insetos Vetores/crescimento & desenvolvimento , Insetos Vetores/parasitologia , Leishmania/fisiologia , Leishmaniose/parasitologia , Leishmaniose/transmissão , Masculino , Psychodidae/crescimento & desenvolvimento , Psychodidae/parasitologia , Estações do Ano
6.
J Med Entomol ; 58(6): 2186-2195, 2021 11 09.
Artigo em Inglês | MEDLINE | ID: mdl-34448004

RESUMO

Wolbachia pipientis (Hertig) is an endosymbiotic microorganism widespread among arthropods and other invertebrate hosts, and employed in strategies to reduce the incidence of arthropod-borne diseases. Here, we used a PCR-based approach for 16S RNA and wsp genes to investigate the prevalence, geographical distribution, and strains of Wolbachia in sand flies (Diptera: Psychodidae: Phlebotominae), the main vectors of the causative agents of leishmaniasis, from three biomes in Brazil: Amazon, Cerrado, and Caatinga. We found that: 1) Wolbachia DNA is present in most (66.7%) of the sampled sand fly species, including vectors of Leishmania spp. (Ross, Trypanosomatida: Trypanosomatidae), 2) the prevalence of Wolbachia DNA varies among species and populations, 3) some strains of Wolbachia may have wider geographical and host range in South America, and 4) two phylogenetic distinct wsp sequences might represent two novel strains for Wolbachia in South America sand flies. Those findings increase the basic knowledge about Wolbachia in South American sand flies and might foster further researches on its use to reduce the transmission of sand fly-borne parasites.


Assuntos
Psychodidae/fisiologia , Wolbachia/isolamento & purificação , Animais , Brasil , DNA Bacteriano/análise , Wolbachia/genética
7.
Parasit Vectors ; 14(1): 371, 2021 Jul 21.
Artigo em Inglês | MEDLINE | ID: mdl-34289883

RESUMO

BACKGROUND: Phlebotomine sand flies (Diptera: Psychodiae) in the Republic of Moldova have been understudied for decades. Our study provides a first update on their occurrence, species composition and bloodmeal sources after 50 years. METHODS: During 5 seasons (2013-2017), 58 localities from 20 regions were surveyed for presence of sand flies using CDC light traps and manual aspirators. Species identification was done by a combination of morphological and molecular approaches (DNA barcoding, MALDI-TOF MS protein profiling). In engorged females, host blood was identified by three molecular techniques (RFLP, cytb sequencing and MALDI-TOF peptide mass mapping). Population structure of most abundant species was studied by cox1 haplotyping; phylogenetic analyses of ITS2 and cox1 genetic markers were used to resolve relationships of other detected species. RESULTS: In total, 793 sand flies were collected at 30 (51.7%) localities from 12 regions of Moldova. Three species were identified by an integrative morphological and molecular approach: Phlebotomus papatasi, P. perfiliewi and Phlebotomus sp. (Adlerius), the first being the most abundant and widespread, markedly anthropophilic based on bloodmeal analyses, occurring also indoors and showing low population structure with only five haplotypes of cox1 detected. Distinct morphological and molecular characters of Phlebotomus sp. (Adlerius) specimens suggest the presence of a yet undescribed species. CONCLUSIONS: Our study revealed the presence of stable sand fly populations of three species in Moldova that represent a biting nuisance as well as a potential threat of pathogen transmission and shall be further studied.


Assuntos
Insetos Vetores/classificação , Leishmaniose/transmissão , Psychodidae/classificação , Animais , Feminino , Haplótipos , Especificidade de Hospedeiro , Humanos , Insetos Vetores/genética , Insetos Vetores/parasitologia , Masculino , Moldávia/epidemiologia , Phlebotomus/classificação , Phlebotomus/genética , Phlebotomus/fisiologia , Filogenia , Psychodidae/genética , Psychodidae/fisiologia , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz
8.
PLoS Negl Trop Dis ; 15(7): e0009545, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-34252099

RESUMO

BACKGROUND: Leishmaniasis is an emerging infectious disease reported in the north and south of Thailand of which patients with HIV/AIDS are a high risk group for acquiring the infection. A lack of information regarding prevalence, and the risk association of Leishmania infection among asymptomatic immunocompetent hosts needs further investigation. Information on potential vectors and animal reservoirs in the affected areas is also important to control disease transmission. METHODS: An outbreak investigation and a cross-sectional study were conducted following one index case of cutaneous leishmaniasis (CL) caused by L. martiniquensis in an immunocompetent male patient reported in August 2015, Chiang Rai Province, Thailand. From September to November 2015, a total of 392 participants at two study areas who were related to the index case, 130 students at a semi-boarding vocational school and 262 hill tribe villagers in the patient's hometown, were recruited in this study. The nested internal transcribed spacer 1-PCR (ITS1-PCR) was performed to detect Leishmania DNA in buffy coat, and nucleotide sequencing was used to identify species. Antibody screening in plasma was performed using the Direct Agglutination Test (DAT), and associated risk factors were analyzed using a standardized questionnaire. Captured sandflies within the study areas were identified and detected for Leishmania DNA using nested ITS1-PCR. Moreover, the animal reservoirs in the study areas were also explored for Leishmania infection. RESULTS: Of 392 participants, 28 (7.1%) were positive for Leishmania infection of which 1 (4.8%) was L. martiniquensis, 12 (57.1%) were L. orientalis and 8 (38.1%) were Leishmania spp. Of 28, 15 (53.6%) were DAT positive. None showed any symptoms of CL or visceral leishmaniasis. Risk factors were associated with being female (adjusted odds ratio, AOR 2.52, 95%CI 1.01-6.26), increasing age (AOR 1.05, 95%CI 1.02-1.08), having an animal enclosure in a housing area (AOR 3.04, 95%CI 1.13-8.22), being exposed to termite mounds (AOR 3.74, 95%CI 1.11-12.58) and having domestic animals in a housing area (AOR 7.11, 95%CI 2.08-24.37). At the semi-boarding vocational school, six Sergentomyia gemmea samples were PCR positive for DNA of L. orientalis and one S. gemmea was PCR positive for DNA of L. donovani/L. infantum. Additionally, one Phlebotomus stantoni was PCR positive for DNA of L. martiniquensis, and one black rat (Rattus rattus) was PCR positive for DNA of L. martiniquensis. CONCLUSION: This information could be useful for monitoring Leishmania infection among immunocompetent hosts in affected areas and also setting up strategies for prevention and control. A follow-up study of asymptomatic individuals with seropositive results as well as those with positive PCR results is recommended.


Assuntos
Leishmania/fisiologia , Leishmaniose/parasitologia , Adolescente , Animais , Animais Domésticos/sangue , Animais Domésticos/parasitologia , Animais Selvagens/sangue , Animais Selvagens/parasitologia , Anticorpos Antiprotozoários/sangue , Criança , Pré-Escolar , Estudos Transversais , Feminino , Humanos , Lactente , Insetos Vetores/parasitologia , Leishmania/genética , Leishmania/isolamento & purificação , Leishmaniose/sangue , Leishmaniose/epidemiologia , Leishmaniose/imunologia , Masculino , Psychodidae/parasitologia , Psychodidae/fisiologia , Características de Residência/estatística & dados numéricos , Tailândia/epidemiologia , Adulto Jovem
9.
Med Vet Entomol ; 35(4): 625-632, 2021 12.
Artigo em Inglês | MEDLINE | ID: mdl-34309051

RESUMO

Phlebotomine sand flies are vectors of Leishmania parasites that cause leishmaniases. Both sexes of sand flies feed on plants primarily for sugars, although the chemical cues that mediate attraction to host plants remain largely unknown. Previously, using coupled gas chromatography-mass spectrometry, the authors identified several volatile organic compounds (VOCs) common to preferred host plants for selected Afrotropical sand flies from the Fabaceae family. Of the identified volatiles, the significance of the monoterpenes linalool oxide, ocimene and p-cymene and the benzenoid m-cresol, p-cresol in sand fly behaviour is unknown. In olfactometer assays, the authors tested these compounds singly and in blends for their attractiveness to Phlebotomus duboscqi, cutaneous leishmaniasis vector in Kenya. In dose-response assays, single compounds increased the responses of males and females over controls, but their optimum attractive doses varied between the sexes. Two five-component blends, referred to as Blend-f and Blend-m for females and males respectively, were formulated and tested in dose-response assays against 1-octen-3-ol (positive control). The results of the present study showed that males and females were significantly attracted to varying levels of the two blends. In pairwise assays, the authors evaluated the most attractive of these blends to each sex (i.e., Blend Am for male against Blend Bf for female), revealing that males were attracted to both blends at varying levels, whereas females were indifferent. The study's results demonstrate that plant-derived VOCs can be exploited for sand fly management.


Assuntos
Leishmaniose Cutânea , Phlebotomus , Psychodidae , Compostos Orgânicos Voláteis , Animais , Feminino , Quênia , Leishmaniose Cutânea/veterinária , Masculino , Phlebotomus/parasitologia , Psychodidae/fisiologia
10.
BMC Infect Dis ; 21(1): 455, 2021 May 19.
Artigo em Inglês | MEDLINE | ID: mdl-34011276

RESUMO

BACKGROUND: Leishmaniasis is one of the ten most important neglected tropical diseases worldwide. Understanding the distribution of vectors of visceral and cutaneous leishmaniasis (VL/CL) is one of the significant strategic frameworks to control leishmaniasis. In this study, the extent of the bioclimatic variability was investigated to recognize a rigorous cartographic of the spatial distribution of VL/CL vectors as risk-maps using ArcGIS modeling system. Moreover, the effect of bioclimatic diversity on the fold change expression of genes possessing vaccine traits (SP15 and LeIF) was evaluated in each bioclimatic region using real-time PCR analysis. METHODS: The Inverse Distance Weighting interpolation method was used to obtain accurate geography map in closely-related distances. Bioclimatic indices were computed and vectors spatial distribution was analyzed in ArcGIS10.3.1 system. Species biodiversity was calculated based on Shannon diversity index using Rv.3.5.3. Expression fold change of SP15 and LeIF genes was evaluated using cDNA synthesis and RT-qPCR analysis. RESULTS: Frequency of Phlebotomus papatasi was predominant in plains areas of Mountainous bioclimate covering the CL hot spots. Mediterranean region was recognized as an important bioclimate harboring prevalent patterns of VL vectors. Semi-arid bioclimate was identified as a major contributing factor to up-regulate salivary-SP15 gene expression (P = 0.0050, P < 0.05). Also, Mediterranean bioclimate had considerable effect on up-regulation of Leishmania-LeIF gene in gravid and semi-gravid P. papatasi population (P = 0.0109, P < 0.05). CONCLUSIONS: The diversity and spatial distribution of CL/VL vectors associated with bioclimatic regionalization obtained in our research provide epidemiological risk maps and establish more effectively control measures against leishmaniasis. Oscillations in gene expression indicate that each gene has its own features, which are profoundly affected by bioclimatic characteristics and physiological status of sand flies. Given the efficacy of species-specific antigens for vaccine production, it is essential to consider bioclimatic factors that have a fundamental role in affecting the regulatory regions of environmentally responsive loci for genes used in vaccine design.


Assuntos
Insetos Vetores/fisiologia , Leishmaniose Cutânea/transmissão , Leishmaniose Visceral/transmissão , Psychodidae/fisiologia , Distribuição Animal/fisiologia , Animais , Biodiversidade , Clima , Ecossistema , Feminino , Regulação da Expressão Gênica/imunologia , Sistemas de Informação Geográfica , Humanos , Irã (Geográfico)/epidemiologia , Leishmaniose Cutânea/epidemiologia , Leishmaniose Visceral/epidemiologia , Masculino
11.
J Med Entomol ; 58(6): 2488-2494, 2021 11 09.
Artigo em Inglês | MEDLINE | ID: mdl-33884431

RESUMO

The transmission of pathogens that cause leishmaniases occurs by the bite of female sand flies (Diptera: Psychodidae) in their vertebrate hosts, which makes the identification of their bloodmeal sources an important step for the control and epidemiology of these diseases. In Brazil, the state of Roraima has a great diversity of sand flies, vertebrate hosts, and protozoan Leishmania, but little is known about the host blood-feeding preferences of sand flies. Thus, we evaluated the bloodmeal sources of sand flies collected from their sylvatic habitats in Parque Nacional do Viruá, Roraima. Fieldwork was carried-out between 13th and 18th August 2019 using CDC light traps. Sand flies were slide-mounted and morphologically identified using the head and last segments of the abdomen. Engorged females had their DNA extracted, followed by amplification and sequencing of the cytochrome b (cytb) molecular marker for vertebrates. Sequences were analyzed and compared with those from GenBank using the BLASTn search tool, in addition to the reconstruction of a phylogenetic tree to demonstrate the clustering pattern of these sequences. A total of 1,209 sand flies were identified, comprising 20 species, in which the most abundant were Psychodopygus ayrozai (Barretto and Coutinho) (42.10%) and Psychodopygus chagasi (Costa Lima) (26.22%). Bloodmeal source identification was successfully performed for 34 sand flies, that confirm four vertebrate species, being the most abundant the armadillo Dasypus novemcinctus Linnaeus, 1758 (Cingulata: Dasypodidae).


Assuntos
Cadeia Alimentar , Insetos Vetores/fisiologia , Psychodidae/fisiologia , Animais , Brasil , Comportamento Alimentar , Leishmaniose/transmissão , Reação em Cadeia da Polimerase , Vertebrados
12.
J Med Entomol ; 58(4): 1952-1957, 2021 07 16.
Artigo em Inglês | MEDLINE | ID: mdl-33724346

RESUMO

Studies of the geographic distribution of sand flies and the factors associated with their occurrence are necessary to understand the risk of leishmaniasis transmission. The objective of this study was to characterize the sand fly fauna, particularly the spatial distribution of Lutzomyia longipalpis (Lutz & Neiva), and correlate these with climate factors in the Dourados municipality, Brazil. The collection of sand flies was carried out with CDC Light Traps over two periods: at six sites for three consecutive nights each month from August 2012 to July 2013; and at four other sites for two consecutive nights each month from April 2017 to February 2018. We collected 591 sand flies in the first period and 121 in the second period for a total of 712 sand flies; 697 of the total collected were Lu. longipalpis. The minimum and maximum sand fly infestation rate (sites with vector presence) was 11.1% and 83.33% in the first period, and 0% and 50.0% in the second period. No sand flies with Leishmania were identified via PCR. Lu. longipalpis presented an aggregate disposition with excellent adjustment. Rainfall and relative humidity were the abiotic factors that influenced the vector infestation level. The aggregate distribution for this species was predicted by the environmental factors that favor the proliferation of Lu. longipalpis. The results of this study should assist in devising measures to control sand flies in Dourados, Brazil.


Assuntos
Distribuição Animal , Psychodidae , Animais , Brasil/epidemiologia , Clima , Umidade , Controle de Insetos , Insetos Vetores/classificação , Insetos Vetores/fisiologia , Leishmaniose/transmissão , Modelos Estatísticos , Dinâmica Populacional , Psychodidae/classificação , Psychodidae/fisiologia , Estações do Ano
13.
BMC Infect Dis ; 21(1): 269, 2021 Mar 17.
Artigo em Inglês | MEDLINE | ID: mdl-33731042

RESUMO

BACKGROUND: Cutaneous leishmaniasis (CL), a neglected tropical disease, represents a significant public health problem in many endemic countries including Yemen. The ongoing armed conflict that started in March 2015 has had a negative impact on the entire healthcare system as well as on infectious disease control programmes. Therefore, this cross-sectional study aimed to assess knowledge and attitude towards CL among rural endemic communities in southwestern Yemen. METHODS: Five hundred households in five areas of Shara'b district of Taiz governorate were randomly selected to participate in a quantitative survey. A pretested structured questionnaire was used to collect data on the sociodemographic characteristics of the participants, their knowledge and attitude towards CL and their knowledge on the sand fly vector. RESULTS: The analysis was conducted on a final sample of 466 individuals (62.7% males and 37.3% females) aged between 18 and 70 years. Among the participants, 21.5% were non-educated while 39.7 and 20.8% had completed secondary school and tertiary education, respectively. Although the participants were aware of CL, about three quarters (77.7%) of them had poor overall knowledge about disease transmission, clinical presentation, treatment, and prevention. Interestingly, approximately half of the participants (49.1%) were able to differentiate sand flies from other flies and mosquitoes. However, only 14.8% of the participants knew about the role of the phlebotomine sand fly in the transmission of CL. Only 36.6% believed that CL can be prevented and 49.6% had a negative attitude towards the disease. Univariate and multivariate analyses showed that age and gender were the significant determinants of knowledge about CL and the sand fly vector among the studied population. CONCLUSION: A poor level of knowledge about the different epidemiological aspects of CL was found among rural CL-endemic communities in Taiz. This factor, together with the major collapse of the healthcare infrastructure due to the ongoing civil war in Yemen, may be contributing to the continued endemicity of CL in the governorate. It is therefore recommended that health education on CL transmission and prevention should be provided to the targeted communities.


Assuntos
Conhecimentos, Atitudes e Prática em Saúde , Leishmaniose Cutânea/epidemiologia , População Rural/estatística & dados numéricos , Adolescente , Adulto , Idoso , Animais , Estudos Transversais , Feminino , Humanos , Insetos Vetores/fisiologia , Leishmaniose Cutânea/prevenção & controle , Leishmaniose Cutânea/transmissão , Masculino , Pessoa de Meia-Idade , Psychodidae/fisiologia , Inquéritos e Questionários , Iêmen/epidemiologia , Adulto Jovem
14.
PLoS Negl Trop Dis ; 15(2): e0009080, 2021 02.
Artigo em Inglês | MEDLINE | ID: mdl-33534804

RESUMO

BACKGROUND: The rising incidence of visceral leishmaniasis due to Leishmania infantum requires novel methods to control transmission by the sand fly vector. Indoor residual spraying of insecticide (IRS) against these largely exophilic / exophagic vectors may not be the most effective method. A synthetic copy of the male sex-aggregation pheromone of the key vector species Lutzomyia longipalpis in the Americas, was co-located with residual pyrethroid insecticide, and tested for its effects on vector abundance, hence potential transmission, in a Brazilian community study. METHODS: Houses within eight defined semi-urban blocks in an endemic municipality in Brazil were randomised to synthetic pheromone + insecticide or to placebo treatments. A similar number of houses located >100m from each block were placebo treated and considered as "True Controls" (thus, analysed as three trial arms). Insecticide was sprayed on a 2.6m2 surface area of the property boundary or outbuilding wall, co-located within one metre of 50mg synthetic pheromone in controlled-release dispensers. Vector numbers captured in nearby CDC light traps were recorded at monthly intervals over 3 months post intervention. Recruited sentinel houses under True Control and pheromone + insecticide treatments were similarly monitored at 7-9 day intervals. The intervention effects were estimated by mixed effects negative binomial models compared to the True Control group. RESULTS: Dose-response field assays using 50mg of the synthetic pheromone captured a mean 4.8 (95% C.L.: 3.91, 5.80) to 6.3 (95% C.L.: 3.24, 12.11) times more vectors (female Lu. longipalpis) than using 10mg of synthetic pheromone. The intervention reduced household female vector abundance by 59% (C.L.: 48.7, 66.7%) (IRR = 0.41) estimated by the cross-sectional community study, and by 70% (C.L.: 56.7%, 78.8%) estimated by the longitudinal sentinel study. Similar reductions in male Lu. longipalpis were observed. Beneficial spill-over intervention effects were also observed at nearby untreated households with a mean reduction of 24% (95% C.L.: 0.050%, 39.8%) in female vectors. The spill-over effect in untreated houses was 44% (95% C.L.: 29.7%, 56.1%) as effective as the intervention in pheromone-treated houses. Ownership of chickens increased the intervention effects in both treated and untreated houses, attributed to the suspected synergistic attraction of the synthetic pheromone and chicken kairomones. The variation in IRR between study blocks was not associated with inter-household distances, household densities, or coverage (proportion of total households treated). CONCLUSIONS: The study confirms the entomological efficacy of the lure-and-kill method to reduce the abundance of this important sand fly vector in treated and untreated homesteads. The outcomes were achieved by low coverage and using only 1-2% of the quantity of insecticide as normally required for IRS, indicating the potential cost-effectiveness of this method. Implications for programmatic deployment of this vector control method are discussed.


Assuntos
Controle de Insetos/métodos , Inseticidas/farmacologia , Feromônios/farmacologia , Psychodidae/efeitos dos fármacos , Psychodidae/fisiologia , Animais , Brasil , Galinhas , Estudos Transversais , Características da Família , Feminino , Humanos , Incidência , Insetos Vetores/efeitos dos fármacos , Leishmania infantum/fisiologia , Leishmaniose Visceral , Masculino , Piretrinas/farmacologia
15.
PLoS Negl Trop Dis ; 15(2): e0009041, 2021 02.
Artigo em Inglês | MEDLINE | ID: mdl-33556068

RESUMO

The bioecology of phlebotomine sand flies is intimately linked to the utilization of environmental resources including plant feeding. However, plant feeding behavior of sand flies remains largely understudied for Afrotropical species. Here, using a combination of biochemical, molecular, and chemical approaches, we decipher specific plant-feeding associations in field-collected sand flies from a dry ecology endemic for leishmaniasis in Kenya. Cold-anthrone test indicative of recent plant feeding showed that fructose positivity rates were similar in both sand fly sexes and between those sampled indoors and outdoors. Analysis of derived sequences of the ribulose-1,5-bisphosphate carboxylase large subunit gene (rbcL) from fructose-positive specimens implicated mainly Acacia plants in the family Fabaceae (73%) as those readily foraged on by both sexes of Phlebotomus and Sergentomyia. Chemical analysis by high performance liquid chromatography detected fructose as the most common sugar in sand flies and leaves of selected plant species in the Fabaceae family. Analysis of similarities (ANOSIM) of the headspace volatile profiles of selected Fabaceae plants identified benzyl alcohol, (Z)-linalool oxide, (E)-ß-ocimene, p-cymene, p-cresol, and m-cresol, as discriminating compounds between the plant volatiles. These results indicate selective sand fly plant feeding and suggest that the discriminating volatile organic compounds could be exploited in attractive toxic sugar- and odor- bait technologies control strategies.


Assuntos
Herbivoria/fisiologia , Psychodidae/fisiologia , Animais , Comportamento Animal , Feminino , Insetos Vetores/parasitologia , Quênia , Leishmaniose/microbiologia , Masculino , Plantas , Psychodidae/metabolismo , Psychodidae/parasitologia , Fatores Sexuais
16.
PLoS Negl Trop Dis ; 15(2): e0009062, 2021 02.
Artigo em Inglês | MEDLINE | ID: mdl-33524028

RESUMO

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.


Assuntos
Ecossistema , Controle de Insetos/métodos , Insetos Vetores/fisiologia , Leishmaniose/transmissão , Psychodidae/fisiologia , Volatilização , Animais , Biodiversidade , Cruzamento , Bovinos , Estudos Transversais , Ecologia , Feminino , Humanos , Controle de Insetos/instrumentação , Quênia , Leishmaniose/prevenção & controle , Masculino , Estações do Ano , Especificidade da Espécie , Compostos Orgânicos Voláteis
17.
Parasit Vectors ; 14(1): 53, 2021 Jan 18.
Artigo em Inglês | MEDLINE | ID: mdl-33461609

RESUMO

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.


Assuntos
DNA de Protozoário/genética , Leishmania donovani/genética , Leishmania major/genética , Leishmaniose Visceral/epidemiologia , Psychodidae/parasitologia , Trypanosoma/genética , Distribuição Animal , Animais , Sangue/metabolismo , DNA Intergênico/genética , Entomologia/métodos , Feminino , Humanos , Procaviídeos , Insetos Vetores/parasitologia , Quênia/epidemiologia , Leishmania donovani/isolamento & purificação , Leishmania major/isolamento & purificação , Leishmaniose Visceral/prevenção & controle , Leishmaniose Visceral/transmissão , Masculino , Refeições , Camundongos , Psychodidae/classificação , Psychodidae/genética , Psychodidae/fisiologia , Trypanosoma/isolamento & purificação
18.
Parasit Vectors ; 14(1): 38, 2021 Jan 11.
Artigo em Inglês | MEDLINE | ID: mdl-33430944

RESUMO

BACKGROUND: Phlebotomines are a group of insects which include vectors of the Leishmania parasites that cause visceral leishmaniasis (VL) and cutaneous leishmaniasis (CL), diseases primarily affecting populations of low socioeconomic status. VL in Brazil is caused by Leishmania infantum, with transmission mainly attributed to Lutzomyia longipalpis, a species complex of sand fly, and is concentrated mainly in the northeastern part of the country. CL is distributed worldwide and occurs in five regions of Brazil, at a higher incidence in the north and northeast regions, with etiological agents, vectors, reservoirs and epidemiological patterns that differ from VL. The aim of this study was to determine the composition, distribution and ecological relationships of phlebotomine species in an Atlantic Forest conservation unit and nearby residential area in northeastern Brazil. METHODS: Centers for Disease Control and Shannon traps were used for collections, the former at six points inside the forest and in the peridomestic environment of surrounding residences, three times per month for 36 months, and the latter in a forest area, once a month for 3 months. The phlebotomines identified were compared with climate data using simple linear correlation, Pearson's correlation coefficient and cross-correlation. The estimate of ecological parameters was calculated according to the Shannon-Wiener diversity index, standardized index of species abundance and the dominance index. RESULTS: A total of 75,499 phlebotomines belonging to 11 species were captured in the CDC traps, the most abundant being Evandromyia walkeri, Psychodopygus wellcomei and Lu. longipalpis. Evandromyia walkeri abundance was most influenced by temperature at collection time and during the months preceding collection and rainfall during the months preceding collection. Psychodopygus wellcomei abundance was most affected by rainfall and relative humidity during the collection month and the month immediately preceding collection time. Lutzomyia longipalpis abundance showed a correlation with temperature and the rainfall during the months preceding collection time. The Shannon trap contained a total of 3914 phlebotomines from these different species. Psychodopygus wellcomei, accounting for 91.93% of the total, was anthropophilic and active mainly at night. CONCLUSIONS: Most of the species collected in the traps were seasonal and exhibited changes in their composition and population dynamics associated with local adaptions. The presence of vectors Ps. wellcomei and Lu. longipalpis underscore the epidemiological importance of these phlebotomines in the conservation unit and surrounding anthropized areas. Neighboring residential areas should be permanently monitored to prevent VL or CL transmission and outbreaks.


Assuntos
Conservação dos Recursos Naturais , Florestas , Insetos Vetores/parasitologia , Leishmania infantum/fisiologia , Psychodidae/parasitologia , Animais , Brasil/epidemiologia , Feminino , Insetos Vetores/classificação , Leishmaniose Cutânea/epidemiologia , Leishmaniose Cutânea/transmissão , Masculino , Dinâmica Populacional , Psychodidae/classificação , Psychodidae/fisiologia , Estações do Ano , Temperatura
19.
J Med Entomol ; 58(1): 480-485, 2021 01 12.
Artigo em Inglês | MEDLINE | ID: mdl-32808985

RESUMO

A 2-yr sand fly (Diptera: Psychodidae) seasonality study was performed in Attica Region, Greece, from June 2017 until November 2018, aiming also to detect the presence of Leishmania infection in the collected sand flies. In total, 701 sand flies were collected from urban areas within the Attica Region using BG-Sentinel traps, set weekly in eight fixed sites. Five species were identified morphologically and molecularly, namely Phlebotomus tobbi (Adler and Theodor), which was most the most commonly collected species, followed by P. Neglectus (Tonnoir), P. papatasi (Scopoli), P. simici (Theodor), and Sergentomyia minuta (Rondani). During both survey years sand fly populations peaked in late August to early September. Fifty-nine monospecific pools were examined for Leishmania detection by analyzing the ITS1 nuclear region using both RFLPs and sequencing, seven of which were found positive. Leishmania DNA was identified as L. infantum in six pools (five P. papatasi and one P. tobbi), whereas in one P. papatasi pool Leishmania DNA was identified as L. tropica. This is the first time that L. tropica has been detected in naturally infected sand flies from the Attica Region as well as in central Greece, while previously it has only been detected in sand flies collected from Central Macedonia (Northern Greece).


Assuntos
Insetos Vetores/fisiologia , Insetos Vetores/parasitologia , Leishmania/isolamento & purificação , Psychodidae/fisiologia , Psychodidae/parasitologia , Animais , Grécia , Dinâmica Populacional
20.
PLoS Negl Trop Dis ; 14(10): e0008798, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-33079936

RESUMO

BACKGROUND: In South America the sand fly Lutzomyia longipalpis is the predominant vector of Leishmania infantum, the parasite that causes canine and human visceral leishmaniasis. Co-location of synthetic male sex-aggregation pheromone with an insecticide provided protection against canine seroconversion, parasite infection, reduced tissue parasite loads, and female sand fly densities at households. Optimising the sex-aggregation pheromone + insecticide intervention requires information on the distance over which female and male Lu. longipalpis would be attracted to the synthetic pheromone in the field. METHODOLOGY/PRINCIPAL FINDINGS: Wild Lu. longipalpis were collected at two peridomestic study sites in Governador Valadares (Minas Gerais, Brazil). Sand flies were marked with coloured fluorescent powder using an improved protocol and then released into an existing domestic chicken shed at two independent sites, followed by recapture at synthetic-pheromone host-odour baited traps placed up to 30 metres distant from the release point. In total 1704 wild-caught Lu. longipalpis were released into the two chicken sheds. Overall 4.3% of the marked flies were recaptured in the pheromone baited experimental chicken sheds compared to no marked flies recaptured in the control sheds. At the first site, 14 specimens (10.4% of the marked and released specimens) were recaptured at 10m, 36 (14.8%) at 20m, and 15 (3.4%) at 30m. At the second site, lower recapture rates were recorded; 8 marked specimens (1.3%) were recaptured at 5 and 10m and no marked specimens were recaptured at 15m. Approximately 7x more marked males than females were recaptured although males were only 2x as common as females in the released population. 52% of the marked Lu. longipalpis were collected during the first night of sampling, 32% on the second night, and 16% on the third night. CONCLUSIONS/SIGNIFICANCE: The study established that both male and female sand flies can be attracted to the synthetic sex-aggregation pheromone in the presence of host odour over distances up to at least 30m in the field depending on local environmental and meterological conditions.


Assuntos
Insetos Vetores/efeitos dos fármacos , Psychodidae/efeitos dos fármacos , Psychodidae/parasitologia , Atrativos Sexuais/síntese química , Atrativos Sexuais/farmacologia , Animais , Comportamento Animal/efeitos dos fármacos , Brasil , Feminino , Humanos , Controle de Insetos , Insetos Vetores/parasitologia , Insetos Vetores/fisiologia , Leishmania infantum/fisiologia , Leishmaniose Visceral/parasitologia , Leishmaniose Visceral/transmissão , Masculino , Psychodidae/fisiologia
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