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Silva FA, Costa DA, Silva BHM, Alves AF, Souza SJDE, Silva GMBDA, Meneses JM, Matos-Rocha TJ, Christoffersen ML, Cavalcanti MGS. Identification of phlebotomine sand fly (Diptera: Psychodidae) in Atlantic forest fragments and their dispersal to urban area. AN ACAD BRAS CIENC 2023; 95:e20191596. [PMID: 38055605 DOI: 10.1590/0001-3765202320191596] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2019] [Accepted: 04/13/2020] [Indexed: 12/08/2023] Open
Abstract
The geographical distribution of sand flies in Brazil has been the subject of some studies, yet there is no information about the phlebotomine fauna in João Pessoa, State of Paraíba, Brazil. The aim of this work is to evaluate the occurrence and distribution of sand flies in the Atlantic forest fragments and to evaluate a possible dispersion in 06 nearby districts. Light traps were used during three consecutive nights, supplemented by an aspirator during the dry period and rainy season. A total of 222 sand flies were found, 143 (130 males and 13 females) in the Atlantic forest, and 79 in urban areas. During the entire dry season, three species of phlebotomine sand flies were recorded in 11 forest fragments, Lutzomyia longipalpis, Lu. migonei and Lu. whitmani. During the rainy season, only Lu. longipalpis was found. This was the only species identified in the studied neighborhoods during both seasons. The differences in diversity of sand flies encountered between natural habitats and urban areas may thus be correlated mostly with adaptations to particular habitats and availability of food. One species (Lu. longipalpis) appears to be rapidly adapting to urban areas because of deforestation.
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Affiliation(s)
- Francisco A Silva
- Programa de Pós-Graduação em Desenvolvimento e Meio Ambiente (PRODEMA), Via Expressa Padre Zé, s/n, Castelo Branco, 58051-900 João Pessoa, PB, Brazil
- Universidade Federal da Paraíba, Laboratório de Endemias, Núcleo de Medicina Tropical, Rua Tabelião Stanislau Eloy, s/n, Castelo Branco, 58051-900 João Pessoa, PB, Brazil
| | - Dimítri A Costa
- Programa de Pós-Graduação em Desenvolvimento e Meio Ambiente (PRODEMA), Via Expressa Padre Zé, s/n, Castelo Branco, 58051-900 João Pessoa, PB, Brazil
| | - Breno Henrique M Silva
- Universidade Federal da Paraíba, Laboratório de Endemias, Núcleo de Medicina Tropical, Rua Tabelião Stanislau Eloy, s/n, Castelo Branco, 58051-900 João Pessoa, PB, Brazil
| | - Adriano Francisco Alves
- Universidade Federal da Paraíba, Laboratório de Endemias, Núcleo de Medicina Tropical, Rua Tabelião Stanislau Eloy, s/n, Castelo Branco, 58051-900 João Pessoa, PB, Brazil
| | - Sérgio Joel DE Souza
- Programa de Pós-Graduação em Desenvolvimento e Meio Ambiente (PRODEMA), Via Expressa Padre Zé, s/n, Castelo Branco, 58051-900 João Pessoa, PB, Brazil
- Universidade Federal da Paraíba, Laboratório de Endemias, Núcleo de Medicina Tropical, Rua Tabelião Stanislau Eloy, s/n, Castelo Branco, 58051-900 João Pessoa, PB, Brazil
- Secretaria de Estado de Saúde da Paraíba (SES-PB), Núcleo de Entomologia e Pesquisa Operacional, Av. Pedro II, 1826, Torre, 58040-903 João Pessoa, PB, Brazil
| | - Geuba Maria B DA Silva
- Universidade Federal da Paraíba, Departamento de Ecologia Aplicada, Rua Santa Elizabete, s/n, Centro, 58297-000 Rio Tinto, PB, Brazil
| | - Janaína M Meneses
- Universidade Federal de Campina Grande, Departamento de Engenharia Química, Rua Aprígio Veloso, 882, 58429-900 Campina Grande, PB, Brazil
| | - Thiago José Matos-Rocha
- Programa de Pós-Graduação em Análise de Sistemas Ambientais (PPGASA), Centro Universitário Cesmac, Rua Prof. Ângelo Neto, 258, 57051-530 Maceió, AL, Brazil
- Universidade Estadual de Ciências da Saúde de Alagoas, Av. Dr. Jorge de Lima, 113, 57010-382 Maceió, AL, Brazil
| | - Martin L Christoffersen
- Universidade Federal da Paraíba, Departamento de Sistemática e Ecologia, Via Expressa Padre Zé, s/n, Castelo Branco, 58051-900 João Pessoa, PB, Brazil
| | - Marília Gabriela S Cavalcanti
- Programa de Pós-Graduação em Desenvolvimento e Meio Ambiente (PRODEMA), Via Expressa Padre Zé, s/n, Castelo Branco, 58051-900 João Pessoa, PB, Brazil
- Universidade Federal da Paraíba, Laboratório de Endemias, Núcleo de Medicina Tropical, Rua Tabelião Stanislau Eloy, s/n, Castelo Branco, 58051-900 João Pessoa, PB, Brazil
- Universidade Federal da Paraíba, Departamento de Fisiologia e Patologia (DFP/CCS), Rua Tabelião Stanislau Eloy, s/n, Castelo Branco, 58051-900 João Pessoa, PB, Brazil
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Souza DA, Oliveira-Santos LGR, Infran JDOM, Fernandes WDS, Arrua AEC, Piranda EM, de Oliveira AG. Spatiotemporal changes in exposition risk to leishmaniases vector in residences within a fishing tourism area of Pantanal wetland. PLoS Negl Trop Dis 2023; 17:e0011809. [PMID: 38048353 PMCID: PMC10721170 DOI: 10.1371/journal.pntd.0011809] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Revised: 12/14/2023] [Accepted: 11/20/2023] [Indexed: 12/06/2023] Open
Abstract
Miranda Municipality of Mato Grosso do Sul, borders the Pantanal wetland, a famous fishing destination visited by tourists from all over the world, and is a location where visceral leishmaniasis has been reported. To assess the risk of Leishmania infantum transmission, we studied the sandfly community, focusing on known vector and parasite presence. We conducted light trap collections twice per month at nine sites within the city (including two forested areas) for one year. We collected a total of 12,727 sand flies, 10,891 males and 1,836 females belonging to 11 species: Brumptomyia avellari, Evandromyia aldafalcaoae, Ev. evandroi, Ev. lenti, Ev. sallesi, Ev. walkeri, Lu. longipalpis, Nyssomyia whitmani, Psathyromyia bigeniculata, Pa. hermanlenti and Pa. punctigeniculata. Lutzomyia longipalpis, the proven vector of Leishmania infantum, was captured each month, and was the most abundant species observed, accounting for more than 99% of sand flies captured in most sites, especially where chicken coops were present. Evidence of Leishmania infantum infection was detected in 0.40% of Lu. longipalpis tested. We developed a generalized mixed multilevel model for Lu. longipalpis, that includes within-year seasonality, location of capture (indoors vs. outdoors), vector abundance, and sex ratio. The VL vector was abundant both inside and outside houses. Large numbers of Lu. longipalpis were observed in outdoor sites where domestic animals were present but were absent from forest sites. Our findings suggest high vector populations and Le. infantum presence in a city where tourists could be exposed to visceral leishmaniasis, with significant implications for more surveillance and control activities.
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Affiliation(s)
- Daiana Alovisi Souza
- Graduate Program in Animal Biology, Institute of Biosciences, Federal University of Mato Grosso do Sul, Campo Grande, Brazil
| | | | - Jucelei de Oliveira Moura Infran
- Laboratory of Human Parasitology, Institute of Biosciences, Federal University of Mato Grosso do Sul, Campo Grande, Brazil
- Graduate Program in Infectious and Parasitic Diseases, Faculty of Medicine, Federal University of Mato Grosso do Sul, Campo Grande, Brazil
| | - Wagner de Souza Fernandes
- Laboratory of Human Parasitology, Institute of Biosciences, Federal University of Mato Grosso do Sul, Campo Grande, Brazil
| | - Aline Etelvina Casaril Arrua
- Laboratory of Human Parasitology, Institute of Biosciences, Federal University of Mato Grosso do Sul, Campo Grande, Brazil
| | - Eliane Mattos Piranda
- Laboratory of Human Parasitology, Institute of Biosciences, Federal University of Mato Grosso do Sul, Campo Grande, Brazil
| | - Alessandra Gutierrez de Oliveira
- Graduate Program in Animal Biology, Institute of Biosciences, Federal University of Mato Grosso do Sul, Campo Grande, Brazil
- Laboratory of Human Parasitology, Institute of Biosciences, Federal University of Mato Grosso do Sul, Campo Grande, Brazil
- Graduate Program in Infectious and Parasitic Diseases, Faculty of Medicine, Federal University of Mato Grosso do Sul, Campo Grande, Brazil
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Impact of vector control actions in the abundance of Lutzomyia longipalpis in Montes Claros, Brazil. Acta Trop 2022; 228:106305. [PMID: 34998997 DOI: 10.1016/j.actatropica.2022.106305] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2021] [Revised: 12/29/2021] [Accepted: 01/04/2022] [Indexed: 11/22/2022]
Abstract
Visceral leishmaniasis (VL) is endemic to many states in Brazil. To prevent further expansion of the disease, the Brazilian Ministry of Health adopted integrated measures through the Program of Surveillance and Control of Visceral Leishmaniasis (PSCVL), whose actions include the diagnosis and euthanasia of seropositive dogs (the main domestic reservoirs), the use of residual insecticides, environmental management (EM) to control vector population (mainly Lutzomyia longipalpis phlebotomine), rigorous epidemiological surveillance, and health education. The present study was conducted in areas with recent moderate VL transmission to evaluate the efficacy of vector control activities. The systematic capture of phlebotomine was performed for three consecutive days per month, from August 2015 to July 2017. The number of specimens captured was taken as a representative of the monthly insect population. A total of 38,055 phlebotomine specimens were captured and identified at the species level. Lu. longipalpis was consistently found to be the predominant species (97.7%) each month. In the first year of the study, no intervention was performed. In the second year, two cycles of chemical spraying, EM, or a combination of both were performed before and after the rainy season. All interventions, either individually or in combination, reduced the abundance of Lu. longipalpis in the study area.
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Kniha E, Milchram M, Dvořák V, Halada P, Obwaller AG, Poeppl W, Mooseder G, Volf P, Walochnik J. Ecology, seasonality and host preferences of Austrian Phlebotomus (Transphlebotomus) mascittii Grassi, 1908, populations. Parasit Vectors 2021; 14:291. [PMID: 34051839 PMCID: PMC8164323 DOI: 10.1186/s13071-021-04787-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Accepted: 05/11/2021] [Indexed: 01/05/2023] Open
Abstract
Background Sand flies are principal vectors of the protozoan parasites Leishmania spp. and are widely distributed in all warmer regions of the world, including the Mediterranean parts of Europe. In Central European countries, the sand fly fauna is still under investigation. Phlebotomus mascittii, a suspected but unproven vector of Leishmania infantum, is regarded as the most widely distributed species in Europe. However, many aspects of its biology and ecology remain poorly known. The aim of this study was to provide new data on the biology and ecology of Ph. mascittii in Austria to better understand its current distribution and potential dispersal. Methods Sand flies were collected by CDC light traps at four localities in Austria for 11 (2018) and 15 weeks (2019) during the active sand fly season. Climatic parameters (temperature, relative humidity, barometric pressure and wind speed) were retrospectively obtained for the trapping periods. Sand flies were identified by a combined approach (morphology, DNA barcoding, MALDI-TOF protein profiling), and blood meals of engorged females were analysed by DNA sequencing and MALDI-TOF mass spectrometry. Results In total, 450 individuals of Ph. mascittii were caught. Activity was observed to start at the beginning of June and end at the end of August with peaks in mid-July at three locations and early August at one location. Increased activity was associated with relatively high temperatures and humidity. Also, more individuals were caught on nights with low barometric pressure. Analysis of five identified blood meals revealed chicken (Gallus gallus) and equine (Equus spp.) hosts. Sand fly abundance was generally associated with availability of hosts. Conclusion This study reports unexpectedly high numbers of Ph. mascittii at selected Austrian localities and provides the first detailed analysis of its ecology to date. Temperature and humidity were shown to be good predictors for sand fly activity. Blood meal analyses support the assumption that Ph. mascittii feeds on mammals as well as birds. The study significantly contributes to understanding the ecology of this sand fly species in Central Europe and facilitates prospective entomological surveys. ![]()
Supplementary Information The online version contains supplementary material available at 10.1186/s13071-021-04787-2.
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Affiliation(s)
- Edwin Kniha
- Institute of Specific Prophylaxis and Tropical Medicine, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria
| | - Markus Milchram
- Institute of Zoology, Department of Integrative Biology and Biodiversity Research, University of Natural Resources and Life Sciences, Vienna, Austria
| | - Vít Dvořák
- Department of Parasitology, Faculty of Science, Charles University, Prague, Czech Republic
| | - Petr Halada
- BioCeV, Institute of Microbiology of the Czech Academy of Sciences, Vestec, Czech Republic
| | - Adelheid G Obwaller
- Division of Science, Research and Development, Federal Ministry of Defence, Vienna, Austria
| | - Wolfgang Poeppl
- Department of Dermatology and Tropical Medicine, Military Medical Cluster East, Austrian Armed Forces, Vienna, Austria
| | - Gerhard Mooseder
- Department of Dermatology and Tropical Medicine, Military Medical Cluster East, Austrian Armed Forces, Vienna, Austria
| | - Petr Volf
- Department of Parasitology, Faculty of Science, Charles University, Prague, Czech Republic
| | - Julia Walochnik
- Institute of Specific Prophylaxis and Tropical Medicine, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria.
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Socio-economic and environmental factors associated with the occurrence of canine infection by Leishmania infantum in Teresina, Brazil. Vet Parasitol Reg Stud Reports 2021; 24:100561. [PMID: 34024377 DOI: 10.1016/j.vprsr.2021.100561] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Revised: 02/28/2021] [Accepted: 03/25/2021] [Indexed: 11/21/2022]
Abstract
American visceral leishmaniasis (AVL) is a zoonosis caused by protozoan parasites of the genus Leishmania. In Brazil, the disease is caused by Leishmania infantum and the main vector is the phlebotomine sandfly Lutzomyia longipalpis, found both in natural ecotopes and in the rural and urban environments, being very well adapted to the peridomestic environment. The domestic dog has been incriminated as the main reservoir of the parasite in the urban environment, but the control measures based on culling seropositive dogs have not shown to be effective to contain the spread of the disease throughout the country. Many studies evaluated risk factors for human visceral leishmaniasis but few focused on the socioeconomic and environmental factors associated with infection among dogs. Knowledge of these factors might help identify the conditions that contribute to the maintenance of transmission cycles in the urban environment and identify new targets for intervention. The objective of this study was to assess the association between socioeconomic and environmental factors and the occurrence of canine leishmaniasis at Teresina city, Brazil. This cross-sectional study was developed in ten districts of Teresina, involving 532 houses and 810 dogs. Peripheral blood samples were collected by vein punction using vacutainer tubes without anticoagulant for performing serological test (indirect immunofluorescence - IFI). Serum samples with IFI titers ≥1: 80 were considered positive. Owners of the selected dwellings were interviewed using a semi-structured questionnaire addressing socioeconomic and environment aspects. The association between variables and seropositivity was assessed through multilevel logistic regression models. Global seropositivity was 39%. There was no statistically significant difference between seropositivity and age and sex of animals, literacy of the household head, presence of other domestic animals or with household characteristic like water supply, inadequate sewage disposal system, type of floor and roof. Mixed-breed dogs and those living for a long time in houses with absence of masonry walls and presence of a kennel showed higher odds of seropositivity. These results suggest that some peridomestic characteristics, especially the absence of barriers that allow dogs to have free access to the street, in association with the presence of a kennel, might contribute to maintaining the infection cycle in urban areas. Intervention measures oriented to the management of the peridomestic environment and responsible dog possession could be useful tools for reducing disease burden in endemic area.
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Salomon OD. Lutzomyia longipalpis, Gone with the Wind and Other Variables. NEOTROPICAL ENTOMOLOGY 2021; 50:161-171. [PMID: 32840741 DOI: 10.1007/s13744-020-00811-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Accepted: 08/10/2020] [Indexed: 06/11/2023]
Abstract
Lutzomyia longipalpis (Lutz & Neiva) is the main vector of Leishmania infantum (Nicolle) in America, associated in turn with the current spread and urbanization of American visceral leishmaniasis (AVL). The vector distribution in AVL foci shows a spatial-temporal clustering despite the different epidemiological contexts. The factors associated with the macroscale distribution of Lu. longipalpis as a landscape stratification are discussed in the framework of the process of their adaptation to anthropized environments. On the other hand, the fact that Lu. longipalpis is clustered in only a few hot spots or critical sites suggests that microscale approaches that describe the trap surrounding environment and the availability of refuges and food sources are better at explaining the uneven distribution of this vector, and should contribute, together with macroscale variables, to design operational control strategies. With regard to temporal distribution and climatic or vegetation data obtained by remote sensing as variables to explain and forecast the abundance of Lu. longipalpis, it is necessary to take into account the time lags in relation to the life cycle of the vector, the difference between the level of daily activity and actual abundance, and the differences in critical variables and thresholds according to the region or season. In conclusion, this review shows that it is feasible to characterize the distribution of Lu. longipalpis at focus level and within it to identify the main critical sites, proposing a sequential cost-effectivity strategy for urban AVL surveillance and control.
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Affiliation(s)
- O D Salomon
- Instituto Nacional de Medicina Tropical - INMeT, ANLIS Dr Carlos G Malbrán, INMeT Av Almafuerte s/n, 3370, Puerto Iguazu, Argentina.
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Gonçalves R, de Souza CF, Rontani RB, Pereira A, Farnes KB, Gorsich EE, Silva RA, Brazil RP, Hamilton JGC, Courtenay O. Community deployment of a synthetic pheromone of the sand fly Lutzomyia longipalpis co-located with insecticide reduces vector abundance in treated and neighbouring untreated houses: Implications for control of Leishmania infantum. PLoS Negl Trop Dis 2021; 15:e0009080. [PMID: 33534804 PMCID: PMC7886189 DOI: 10.1371/journal.pntd.0009080] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Revised: 02/16/2021] [Accepted: 12/17/2020] [Indexed: 01/29/2023] Open
Abstract
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. The predominant sand fly vector of the intracellular parasite Leishmania infantum, that causes human and canine visceral leishmaniasis in the Americas, is Lutzomyia longipalpis. Vector control tools to reduce transmission are needed. A sex-aggregation pheromone released by male Lu. longipalpis attracts female conspecifics which facilitates blood-feeding and transmission. This study, conducted in Brazil, quantifies the effects of community deployment of a synthetic version of the sex-aggregation pheromone, in a controlled-release dispenser, and co-located with lethal insecticide applied to a small area of the household compound or outbuilding wall. 50mg synthetic pheromone dispensers were used since they attracted substantially more vectors than 10mg dispensers. Deploying this novel lure-and-kill method to houses in eight replicate study blocks in two suburban endemic areas, demonstrated that it reduces vector numbers at both pheromone + insecticide treated houses, and neighbouring untreated houses. The presence of chickens (a known additional attraction to blood-seeking female Lu. longipalpis) increased the beneficial effects of the intervention. The method used only 1–2% of the quantity of insecticide necessary for IRS for an average sized house. The results demonstrate the efficacy and potential cost-effectiveness of this novel lure-and-kill control method.
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Affiliation(s)
- Raquel Gonçalves
- Zeeman Institute and School of Life Sciences, University of Warwick, Coventry, United Kingdom
| | - Cristian F. de Souza
- Laboratório de Doenças Parasitárias, Instituto Oswaldo Cruz, FIOCRUZ, Rio de Janeiro, Brazil
| | - Reila B. Rontani
- Laboratório de Doenças Parasitárias, Instituto Oswaldo Cruz, FIOCRUZ, Rio de Janeiro, Brazil
| | - Alisson Pereira
- Laboratório de Doenças Parasitárias, Instituto Oswaldo Cruz, FIOCRUZ, Rio de Janeiro, Brazil
| | - Katie B. Farnes
- Zeeman Institute and School of Life Sciences, University of Warwick, Coventry, United Kingdom
| | - Erin E. Gorsich
- Zeeman Institute and School of Life Sciences, University of Warwick, Coventry, United Kingdom
| | - Rafaella A. Silva
- Núcleo de Medicina Tropical, Universidade de Brasilia, Brasília, Federal District, Brazil
- Ministério da Saúde, Departamento de Imunização e Doenças Transmissíveis, Secretaria de Vigilância em Saúde, Brasília, Federal District, Brazil
| | - Reginaldo P. Brazil
- Laboratório de Doenças Parasitárias, Instituto Oswaldo Cruz, FIOCRUZ, Rio de Janeiro, Brazil
| | - James G. C. Hamilton
- Division of Biomedical and Life Sciences, Faculty of Health and Medicine, Lancaster University, Bailrigg, Lancaster, Lancashire, United Kingdom
- * E-mail: (JH); (OC)
| | - Orin Courtenay
- Zeeman Institute and School of Life Sciences, University of Warwick, Coventry, United Kingdom
- * E-mail: (JH); (OC)
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Courtenay O, Dilger E, Calvo-Bado LA, Kravar-Garde L, Carter V, Bell MJ, Alves GB, Goncalves R, Makhdoomi MM, González MA, Nunes CM, Bray DP, Brazil RP, Hamilton JGC. Sand fly synthetic sex-aggregation pheromone co-located with insecticide reduces the incidence of infection in the canine reservoir of visceral leishmaniasis: A stratified cluster randomised trial. PLoS Negl Trop Dis 2019; 13:e0007767. [PMID: 31652261 PMCID: PMC6834291 DOI: 10.1371/journal.pntd.0007767] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Revised: 11/06/2019] [Accepted: 09/09/2019] [Indexed: 12/20/2022] Open
Abstract
OBJECTIVE To evaluate the efficacy of a synthetic sex-aggregation pheromone of the sand fly vector Lu. longipalpis, co-located with residual insecticide, to reduce the infection incidence of Leishmania infantum in the canine reservoir. METHODS A stratified cluster randomised trial was designed to detect a 50% reduction in canine incident infection after 24 months in 42 recruited clusters, randomly assigned to one of three intervention arms (14 cluster each): synthetic pheromone + insecticide, insecticide-impregnated dog collars, or placebo control. Infection incidence was measured by seroconversion to anti-Leishmania serum antibody, Leishmania parasite detection and canine tissue parasite loads. Changes in relative Lu. longipalpis abundance within households were measured by setting three CDC light traps per household. RESULTS A total 1,454 seronegative dogs were followed-up for a median 15.2 (95% C.I.s: 14.6, 16.2) months per cluster. The pheromone + insecticide intervention provided 13% (95% C.I. 0%, 44.0%) protection against anti-Leishmania antibody seroconversion, 52% (95% C.I. 6.2%, 74·9%) against parasite infection, reduced tissue parasite loads by 53% (95% C.I. 5.4%, 76.7%), and reduced household female sand fly abundance by 49% (95% C.I. 8.2%, 71.3%). Variation in the efficacy against seroconversion varied between trial strata. Equivalent protection attributed to the impregnated-collars were 36% (95% C.I. 14.4%, 51.8%), 23% (95% C.I. 0%, 57·5%), 48% (95% C.I. 0%, 73.4%) and 43% (95% C.I. 0%, 67.9%), respectively. Comparison of the two interventions showed no statistically consistent differences in their efficacies; however, the errors were broad for all outcomes. Reductions in sand fly numbers were predominant where insecticide was located (chicken and dog sleeping sites), with no evidence of insecticide-induced repellence onto humans or dogs. CONCLUSION The synthetic pheromone co-located with insecticide provides protection particularly against canine L. infantum parasite transmission and sand fly vector abundance. The effect estimates are not dissimilar to those of the insecticide-impregnated collars, which are documented to reduce canine infection incidence, human infection and clinical VL disease incidence, in different global regions. The trialled novel lure-and-kill approach is a low-cost potential vector control tool against ZVL in the Americas.
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Affiliation(s)
- Orin Courtenay
- Zeeman Institute and School of Life Sciences, University of Warwick, Coventry, United Kingdom
- * E-mail: (OC); (JGCH)
| | - Erin Dilger
- Zeeman Institute and School of Life Sciences, University of Warwick, Coventry, United Kingdom
| | - Leo A. Calvo-Bado
- Zeeman Institute and School of Life Sciences, University of Warwick, Coventry, United Kingdom
| | - Lidija Kravar-Garde
- Zeeman Institute and School of Life Sciences, University of Warwick, Coventry, United Kingdom
| | - Vicky Carter
- School of Life Sciences, Institute of Science & Technology in Medicine, Keele University, Keele, Staffordshire, United Kingdom
| | - Melissa J. Bell
- Zeeman Institute and School of Life Sciences, University of Warwick, Coventry, United Kingdom
| | - Graziella B. Alves
- School of Life Sciences, Institute of Science & Technology in Medicine, Keele University, Keele, Staffordshire, United Kingdom
| | - Raquel Goncalves
- Zeeman Institute and School of Life Sciences, University of Warwick, Coventry, United Kingdom
| | - Muhammad M. Makhdoomi
- Zeeman Institute and School of Life Sciences, University of Warwick, Coventry, United Kingdom
| | - Mikel A. González
- Division of Biomedical and Life Sciences, Faculty of Health and Medicine, Lancaster University, Bailrigg, Lancaster, Lancashire, United Kingdom
| | - Caris M. Nunes
- Faculdade de Medicina Veterinária, Universidade Estadual Paulista (UNESP), Araçatuba, São Paulo, Brazil
| | - Daniel P. Bray
- School of Life Sciences, Institute of Science & Technology in Medicine, Keele University, Keele, Staffordshire, United Kingdom
| | - Reginaldo P. Brazil
- Laboratório de Doenças Parasitárias, Instituto Oswaldo Cruz, Rio de Janeiro, Brazil
| | - James G. C. Hamilton
- Division of Biomedical and Life Sciences, Faculty of Health and Medicine, Lancaster University, Bailrigg, Lancaster, Lancashire, United Kingdom
- * E-mail: (OC); (JGCH)
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9
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Lopes JV, Michalsky EM, Pereira NCL, de Paula AJV, Lara-Silva FO, Silva-Lana R, Fortes-Dias CL, Pinheiro LC, Dias ES. Entomological Studies in Itaúna, Brazil, an Area With Visceral Leishmaniasis Transmission: Fauna Survey, Natural Leishmania Infection, and Molecular Characterization of the Species Circulating in Phlebotomine Sand Flies (Diptera: Psychodidae). JOURNAL OF MEDICAL ENTOMOLOGY 2019; 56:1368-1376. [PMID: 31121044 DOI: 10.1093/jme/tjz061] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2018] [Indexed: 06/09/2023]
Abstract
Among neglected tropical diseases, visceral leishmaniasis (VL) shows great relevance in global terms and is a serious public health concern due to the possibility of severe and lethal forms in humans. In this study, we evaluate entomological factors such as diversity and abundance of phlebotomine sand flies (Diptera:Psychodidae) and the Leishmania species circulating in these species in possible association with VL transmission in the Brazilian town Itaúna. The entomological collections were performed during three consecutive nights, always in the third week of each month, within a period of 12 mo. A total of 1,786 sand fly specimens were collected, from which 20% were collected inside houses. The influence of three local climatic variables (temperature, rainfall, relative humidity) on the population sizes of these insects was evaluated. Temperature was the most influential factor, with a significant positive correlation with the local population size of phlebotomine sand flies collected per month. Lutzomyia longipalpis (Lutz & Neiva, 1912) was the predominant species in the study area. Leishmania DNA was detected in nine out of 133 pools of sand fly females, using nested/PCR, which resulted in a minimal natural infection rate of 2.91%. DNA from Leishmania infantum Nicolle, 1908 (Kinetoplastida: Trypanosomatida), was detected in Evandromyia cortelezzii (Bréthes, 1923), Ev. evandroi (Costa, Lima & Antunes, 1936), Ev. lenti (Mangabeira, 1938), and Ev. termitophila (Martins, Falcão & Silva, 1964), besides Lu. longipalpis. Our study indicates favorable conditions for VL spreading in Itaúna due to the presence of Lu. longipalpis and Le. infantum-infected phlebotomine sand flies.
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Affiliation(s)
- Josiane V Lopes
- Instituto René Rachou, Fundação Oswaldo Cruz, Av. Augusto de Lima, Barro Preto, Belo Horizonte, Minas Gerais, Brasil
| | - Erika M Michalsky
- Instituto René Rachou, Fundação Oswaldo Cruz, Av. Augusto de Lima, Barro Preto, Belo Horizonte, Minas Gerais, Brasil
| | - Nathalia C L Pereira
- Instituto René Rachou, Fundação Oswaldo Cruz, Av. Augusto de Lima, Barro Preto, Belo Horizonte, Minas Gerais, Brasil
| | - Adão J V de Paula
- Instituto René Rachou, Fundação Oswaldo Cruz, Av. Augusto de Lima, Barro Preto, Belo Horizonte, Minas Gerais, Brasil
| | - Fabiana O Lara-Silva
- Instituto René Rachou, Fundação Oswaldo Cruz, Av. Augusto de Lima, Barro Preto, Belo Horizonte, Minas Gerais, Brasil
| | - Rosana Silva-Lana
- Instituto René Rachou, Fundação Oswaldo Cruz, Av. Augusto de Lima, Barro Preto, Belo Horizonte, Minas Gerais, Brasil
| | - Consuelo L Fortes-Dias
- Fundação Ezequiel Dias - Rua Conde Pereira Carneiro 80 Gameleira, Belo Horizonte, Minas Gerais, Brasil
| | - Leticia C Pinheiro
- Instituto René Rachou, Fundação Oswaldo Cruz, Av. Augusto de Lima, Barro Preto, Belo Horizonte, Minas Gerais, Brasil
| | - Edelberto S Dias
- Instituto René Rachou, Fundação Oswaldo Cruz, Av. Augusto de Lima, Barro Preto, Belo Horizonte, Minas Gerais, Brasil
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10
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Barrios SPG, Pereira LE, Nazário Monaco NZ, Graciolli G, Casaril AE, Infran JDOM, de Oliveira EF, Fernandes WDS, Paranhos Filho AC, de Oliveira AG. Synanthropy and diversity of Phlebotominae in an area of intense transmission of visceral leishmaniasis in the South Pantanal floodplain, Midwest Brazil. PLoS One 2019; 14:e0215741. [PMID: 31086366 PMCID: PMC6516641 DOI: 10.1371/journal.pone.0215741] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Accepted: 04/08/2019] [Indexed: 12/15/2022] Open
Abstract
Phlebotomines have been recorded from a wide variety of habitats, and some of these vector species have shown preference for human environments, with high levels of adaptation. This study evaluated the degree of preference of these vectors for urban, rural, and forested environments (synanthropic behavior), as well as the diversity of these species, in three areas (forested, rural, and urban, exhibiting different degrees of anthropogenic changes) in a region of intense transmission of visceral leishmaniasis in Corumbá county, Mato Grosso do Sul, Brazil. Using light traps, sand fly specimens were collected from the three environments simultaneously, from May 2015 to April 2017, totaling 7 213 sand flies of 14 species in eight genera. Nuorteva's synanthropy index was determined for the species Lutzomyia cruzi, Brumptomyia brumpti, Micropygomyia peresi, Lu. forattinii, Martinsmyia oliveirai and Evandromyia corumbaensis. Lutzomyia cruzi, the vector of Leishmania infantum in Corumbá, was the most abundant vector species, recorded from all three areas and sampling plots, on all 24 months investigated. This species exhibited the highest synanthropic index (+75.09), indicating a strong preference for urban environments. Brumptomyia brumpti, Micropygomyia peresi, Lu. forattinii, and Martinsmyia oliveirai showed preference, albeit not strong, for urban environments. Overall, males were more abundant than females (W = 490; p < 0.0001). High density, high synanthropic index, and sustained indoor presence were found for Mi. peresi in the rural area. Monitoring changes in the ecological behavior of sand flies is of vital importance, as these changes may indicate an increased likelihood of leishmaniasis emergence or reemergence.
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Affiliation(s)
- Suellem Petilim Gomes Barrios
- Programa de Pós-Graduação em Doenças Infecciosas e Parasitárias, Universidade Federal de Mato Grosso do Sul, Campo Grande, Mato Grosso do Sul, Brasil
| | - Luciana Escalante Pereira
- Programa de Pós-Graduação em Tecnologias Ambientais, Universidade Federal de Mato Grosso do Sul, Campo Grande, Mato Grosso do Sul, Brasil
| | | | - Gustavo Graciolli
- Instituto de Biociências, Universidade Federal de Mato Grosso do Sul, Campo Grande, Mato Grosso do Sul, Brasil
| | - Aline Etelvina Casaril
- Instituto de Biociências, Universidade Federal de Mato Grosso do Sul, Campo Grande, Mato Grosso do Sul, Brasil
| | | | - Everton Falcão de Oliveira
- Programa de Pós-Graduação em Doenças Infecciosas e Parasitárias, Universidade Federal de Mato Grosso do Sul, Campo Grande, Mato Grosso do Sul, Brasil
- Instituto Integrado de Saúde, Universidade Federal de Mato Grosso do Sul, Campo Grande, Mato Grosso do Sul, Brasil
| | - Wagner de Souza Fernandes
- Programa de Pós-Graduação em Doenças Infecciosas e Parasitárias, Universidade Federal de Mato Grosso do Sul, Campo Grande, Mato Grosso do Sul, Brasil
| | - Antônio Conceição Paranhos Filho
- Faculdade de Engenharia, Arquitetura e Urbanismo e Geografia, Universidade Federal de Mato Grosso do Sul, Campo Grande, Mato Grosso do Sul, Brasil
| | - Alessandra Gutierrez de Oliveira
- Programa de Pós-Graduação em Doenças Infecciosas e Parasitárias, Universidade Federal de Mato Grosso do Sul, Campo Grande, Mato Grosso do Sul, Brasil
- Instituto de Biociências, Universidade Federal de Mato Grosso do Sul, Campo Grande, Mato Grosso do Sul, Brasil
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11
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Buckingham-Jeffery E, Hill EM, Datta S, Dilger E, Courtenay O. Spatio-temporal modelling of Leishmania infantum infection among domestic dogs: a simulation study and sensitivity analysis applied to rural Brazil. Parasit Vectors 2019; 12:215. [PMID: 31064395 PMCID: PMC6505121 DOI: 10.1186/s13071-019-3430-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Accepted: 04/04/2019] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The parasite Leishmania infantum causes zoonotic visceral leishmaniasis (VL), a potentially fatal vector-borne disease of canids and humans. Zoonotic VL poses a significant risk to public health, with regions of Latin America being particularly afflicted by the disease. Leishmania infantum parasites are transmitted between hosts during blood-feeding by infected female phlebotomine sand flies. With a principal reservoir host of L. infantum being domestic dogs, limiting prevalence in this reservoir may result in a reduced risk of infection for the human population. To this end, a primary focus of research efforts has been to understand disease transmission dynamics among dogs. One way this can be achieved is through the use of mathematical models. METHODS We have developed a stochastic, spatial, individual-based mechanistic model of L. infantum transmission in domestic dogs. The model framework was applied to a rural Brazilian village setting with parameter values informed by fieldwork and laboratory data. To ensure household and sand fly populations were realistic, we statistically fitted distributions for these entities to existing survey data. To identify the model parameters of highest importance, we performed a stochastic parameter sensitivity analysis of the prevalence of infection among dogs to the model parameters. RESULTS We computed parametric distributions for the number of humans and animals per household and a non-parametric temporal profile for sand fly abundance. The stochastic parameter sensitivity analysis determined prevalence of L. infantum infection in dogs to be most strongly affected by the sand fly associated parameters and the proportion of immigrant dogs already infected with L. infantum parasites. CONCLUSIONS Establishing the model parameters with the highest sensitivity of average L. infantum infection prevalence in dogs to their variation helps motivate future data collection efforts focusing on these elements. Moreover, the proposed mechanistic modelling framework provides a foundation that can be expanded to explore spatial patterns of zoonotic VL in humans and to assess spatially targeted interventions.
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Affiliation(s)
- Elizabeth Buckingham-Jeffery
- School of Mathematics, University of Manchester, Manchester, UK.
- Zeeman Institute: SBIDER (Systems Biology & Infectious Disease Epidemiology Research), University of Warwick, Coventry, UK.
| | - Edward M Hill
- Zeeman Institute: SBIDER (Systems Biology & Infectious Disease Epidemiology Research), University of Warwick, Coventry, UK
- Warwick Mathematics Institute, University of Warwick, Coventry, UK
| | - Samik Datta
- Population Modelling Group, National Institute of Water and Atmospheric Research, Wellington, New Zealand
- Zeeman Institute: SBIDER (Systems Biology & Infectious Disease Epidemiology Research), University of Warwick, Coventry, UK
| | - Erin Dilger
- Zeeman Institute: SBIDER (Systems Biology & Infectious Disease Epidemiology Research), University of Warwick, Coventry, UK
- School of Life Sciences, University of Warwick, Coventry, UK
| | - Orin Courtenay
- Zeeman Institute: SBIDER (Systems Biology & Infectious Disease Epidemiology Research), University of Warwick, Coventry, UK
- School of Life Sciences, University of Warwick, Coventry, UK
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12
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Quinnell RJ, Soremekun S, Bates PA, Rogers ME, Garcez LM, Courtenay O. Antibody response to sand fly saliva is a marker of transmission intensity but not disease progression in dogs naturally infected with Leishmania infantum. Parasit Vectors 2018; 11:7. [PMID: 29301571 PMCID: PMC5755305 DOI: 10.1186/s13071-017-2587-5] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2017] [Accepted: 12/11/2017] [Indexed: 11/30/2022] Open
Abstract
BACKGROUND Antibody responses to sand fly saliva have been suggested to be a useful marker of exposure to sand fly bites and Leishmania infection and a potential tool to monitor the effectiveness of entomological interventions. Exposure to sand fly bites before infection has also been suggested to modulate the severity of the infection. Here, we test these hypotheses by quantifying the anti-saliva IgG response in a cohort study of dogs exposed to natural infection with Leishmania infantum in Brazil. METHODS IgG responses to crude salivary antigens of the sand fly Lutzomyia longipalpis were measured by ELISA in longitudinal serum samples from 47 previously unexposed sentinel dogs and 11 initially uninfected resident dogs for up to 2 years. Antibody responses were compared to the intensity of transmission, assessed by variation in the incidence of infection between seasons and between dogs. Antibody responses before patent infection were then compared with the severity of infection, assessed using tissue parasite loads and clinical symptoms. RESULTS Previously unexposed dogs acquired anti-saliva antibody responses within 2 months, and the rate of acquisition increased with the intensity of seasonal transmission. Over the following 2 years, antibody responses varied with seasonal transmission and sand fly numbers, declining rapidly in periods of low transmission. Antibody responses varied greatly between dogs and correlated with the intensity of transmission experienced by individual dogs, measured by the number of days in the field before patent infection. After infection, anti-saliva antibody responses were positively correlated with anti-parasite antibody responses. However, there was no evidence that the degree of exposure to sand fly bites before infection affected the severity of the infection. CONCLUSIONS Anti-saliva antibody responses are a marker of current transmission intensity in dogs exposed to natural infection with Leishmania infantum, but are not associated with the outcome of infection.
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Affiliation(s)
- Rupert J. Quinnell
- School of Biology, Faculty of Biological Sciences, University of Leeds, Leeds, UK
| | - Seyi Soremekun
- Zeeman Institute and School of Life Sciences, University of Warwick, Coventry, UK
- Faculty of Infectious Tropical Diseases, Department of Disease Control, London School of Hygiene and Tropical Medicine, London, UK
| | - Paul A. Bates
- Division of Biomedical and Life Sciences, Lancaster University, Lancaster, UK
| | - Matthew E. Rogers
- Faculty of Infectious Tropical Diseases, Department of Disease Control, London School of Hygiene and Tropical Medicine, London, UK
| | - Lourdes M. Garcez
- Instituto Evandro Chagas, Belém, Pará Brazil
- Centro do Ciências Biológicas e da Saúde, Universidade do Estado do Pará, Belém, Pará Brazil
| | - Orin Courtenay
- Zeeman Institute and School of Life Sciences, University of Warwick, Coventry, UK
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13
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Machado TDO, Minuzzi-Souza TTC, Ferreira TDS, Freire LP, Timbó RV, Vital TE, Nitz N, Silva MN, Santos ADS, Sales NMC, Obara MT, Andrade AJD, Gurgel-Gonçalves R. The role of gallery forests in maintaining Phlebotominae populations: potential Leishmania spp. vectors in the Brazilian savanna. Mem Inst Oswaldo Cruz 2017; 112:681-691. [PMID: 28953996 PMCID: PMC5607517 DOI: 10.1590/0074-02760170126] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2017] [Accepted: 05/08/2017] [Indexed: 11/22/2022] Open
Abstract
BACKGROUND Knowledge on synanthropic phlebotomines and their natural infection by Leishmania is necessary for the identification of potential areas for leishmaniasis occurrence. OBJECTIVE To analyse the occurrence of Phlebotominae in gallery forests and household units (HUs) in the city of Palmas and to determine the rate of natural infection by trypanosomatids. METHODS Gallery forests and adjacent household areas were sampled on July (dry season) and November (rainy season) in 2014. The total sampling effort was 960 HP light traps and eight Shannon traps. Trypanosomatids were detected in Phlebotominae females through the amplification of the SSU rDNA region, and the positive samples were used in ITS1-PCR. Trypanosomatid species were identified using sequencing. FINDINGS A total of 1,527 sand flies representing 30 species were captured in which 949 (28 spp.) and 578 (22 spp.) were registered in July and November, respectively. In July, more specimens were captured in the gallery forests than in the HUs, and Nyssomyia whitmani was particularly frequent. In November, most of the specimens were found in the HUs, and again, Ny. whitmani was the predominant species. Lutzomyia longipalpis was commonly found in domestic areas, while Bichromomyia flaviscutellata was most frequent in gallery forests. Molecular analysis of 154 pools of females (752 specimens) identified Leishmania amazonensis, L. infantum, and Crithidia fasciculata in Ny. whitmani, as well as L. amazonensis in Lu. longipalpis, Trypanosoma sp. and L. amazonensis in Pintomyia christenseni, and L. amazonensis in both Psathyromyia hermanlenti and Evandromyia walkeri. MAIN CONCLUSIONS These results show the importance of gallery forests in maintaining Phlebotominae populations in the dry month, as well as their frequent occurrence in household units in the rainy month. This is the first study to identify Leishmania, Trypanosoma, and Crithidia species in Phlebotominae collected in Palmas, Tocantins, Brazil.
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Affiliation(s)
- Tâmara Dias Oliveira Machado
- Universidade de Brasília, Faculdade de Medicina, Área de Patologia, Laboratório de Parasitologia Médica e Biologia de Vetores, Brasília, DF, Brasil.,Instituto Federal de Educação, Ciência e Tecnologia do Tocantins, Coordenação de Ciências Matemáticas e Naturais, Palmas, TO, Brasil
| | - Thaís Tâmara Castro Minuzzi-Souza
- Universidade de Brasília, Faculdade de Medicina, Área de Patologia, Laboratório de Parasitologia Médica e Biologia de Vetores, Brasília, DF, Brasil.,Universidade de Brasília, Faculdade de Medicina, Área de Patologia, Laboratório Interdisciplinar de Biociências, Brasília, DF, Brasil
| | - Tauana de Sousa Ferreira
- Universidade de Brasília, Faculdade de Medicina, Área de Patologia, Laboratório de Parasitologia Médica e Biologia de Vetores, Brasília, DF, Brasil
| | - Luciana Pereira Freire
- Universidade de Brasília, Faculdade de Medicina, Área de Patologia, Laboratório de Parasitologia Médica e Biologia de Vetores, Brasília, DF, Brasil
| | - Renata Velôzo Timbó
- Universidade de Brasília, Faculdade de Medicina, Área de Patologia, Laboratório de Parasitologia Médica e Biologia de Vetores, Brasília, DF, Brasil
| | - Tamires Emanuele Vital
- Universidade de Brasília, Faculdade de Medicina, Área de Patologia, Laboratório Interdisciplinar de Biociências, Brasília, DF, Brasil
| | - Nadjar Nitz
- Universidade de Brasília, Faculdade de Medicina, Área de Patologia, Laboratório Interdisciplinar de Biociências, Brasília, DF, Brasil
| | - Mariana Neiva Silva
- Universidade de Brasília, Faculdade de Medicina, Área de Patologia, Laboratório de Parasitologia Médica e Biologia de Vetores, Brasília, DF, Brasil
| | - Alcinei de Souza Santos
- Instituto Federal de Educação, Ciência e Tecnologia do Tocantins, Coordenação de Ciências Matemáticas e Naturais, Palmas, TO, Brasil
| | - Nathyla Morgana Cunha Sales
- Instituto Federal de Educação, Ciência e Tecnologia do Tocantins, Coordenação de Ciências Matemáticas e Naturais, Palmas, TO, Brasil
| | | | - Andrey José de Andrade
- Universidade de Brasília, Faculdade de Medicina, Área de Patologia, Laboratório de Parasitologia Médica e Biologia de Vetores, Brasília, DF, Brasil.,Universidade Federal do Paraná, Setor de Ciências Biológicas, Departamento de Patologia Básica, Curitiba, PR, Brasil
| | - Rodrigo Gurgel-Gonçalves
- Universidade de Brasília, Faculdade de Medicina, Área de Patologia, Laboratório de Parasitologia Médica e Biologia de Vetores, Brasília, DF, Brasil
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14
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A systematic review and meta-analysis of the prevalence of Leishmania infection in blood donors. Transfus Apher Sci 2017; 56:544-551. [DOI: 10.1016/j.transci.2017.07.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2016] [Revised: 06/05/2017] [Accepted: 07/03/2017] [Indexed: 11/18/2022]
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15
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Pardo RH, Santamaría E, Cabrera OL. Entering and exiting behaviour of the phlebotomine sand fly Lutzomyia longiflocosa (Diptera: Psychodidae) in rural houses of the sub-Andean region of Colombia. Mem Inst Oswaldo Cruz 2017; 112:19-30. [PMID: 27925019 PMCID: PMC5224351 DOI: 10.1590/0074-02760160265] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Accepted: 09/14/2016] [Indexed: 11/22/2022] Open
Abstract
The present study identified the entering and exiting sites for Lutzomyia
longiflocosa in rural houses of the sub-Andean region in Colombia.
Entering sites were identified with sticky traps set up outside the bedrooms, around
the eave openings, and with cage traps enclosing the slits in the doors and windows
inside the bedrooms. Exiting sites were identified by releasing groups of females
indoors. These females were blood fed and marked with fluorescent powders. Females
were recaptured with the trap placement described above but set up on the opposite
sides of the openings. In the entering experiment, a significantly higher number of
females were captured in the sticky traps at the zone nearest the eave openings (n =
142) than those captured in the other zones of the trap (n = 52); similarly, a higher
number of females were captured on the front side of the house (n = 105) than at the
rear side (n = 37). Only two females were collected in the cage trap. In the exiting
experiment, at the ceiling, the highest percentage (86.2%) of females was recaptured
with sticky traps nearest the eave openings and on the front side of the house
(70.0%). Seven females were collected in the cage trap. Lu.
longiflocosa entered and exited houses primarily through the eave
openings in a non-random pattern in relation to the sides of the house.
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Affiliation(s)
- Raúl Hernando Pardo
- Instituto Nacional de Salud, Grupo de Entomología, Bogotá, Colombia.,Universidad de La Salle, Grupo de Entomología y Enfermedades Transmitidas por Vectores, Bogotá, Colombia
| | - Erika Santamaría
- Instituto Nacional de Salud, Grupo de Entomología, Bogotá, Colombia
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16
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Vianna EN, Morais MHF, de Almeida AS, Sabroza PC, Reis IA, Dias ES, Carneiro M. Abundance of Lutzomyia longipalpis in urban households as risk factor of transmission of visceral leishmaniasis. Mem Inst Oswaldo Cruz 2016; 111:302-10. [PMID: 27223866 PMCID: PMC4878299 DOI: 10.1590/0074-02760150366] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2015] [Accepted: 04/09/2016] [Indexed: 11/21/2022] Open
Abstract
Urban occurrence of human and canine visceral leishmaniasis (VL) is linked to households with characteristics conducive to the presence of sand flies. This study proposes an ad hoc classification of households according to the environmental characteristics of receptivity to phlebotominae and an entomological study to validate the proposal. Here we describe the phlebotominae population found in intra- and peridomiciliary environments and analyse the spatiotemporal distribution of the VL vector Lutzomyia longipalpis of households receptive to VL. In the region, 153 households were classified into levels of receptivity to VL followed by entomological surveys in 40 of those properties. Kruskal-Wallis verified the relationship between the households' classification and sand fly abundance and Kernel analysis evaluated L. longipalpis spatial distribution: of the 740 sand flies were captured, 91% were L. longipalpis; 82% were found peridomiciliary whilst the remaining 18% were found intradomiciliary. No statistically significant association was found between sandflies and households levels. L. longipalpis counts were concentrated in areas of high vulnerability and some specific households were responsible for the persistence of the infestation. L. longipalpis prevails over other sand fly species for urban VL transmission. The entomological study may help target the surveillance and vector control strategies to domiciles initiating and/or maintaining VL outbreaks.
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Affiliation(s)
- Elisa Neves Vianna
- Universidade Federal de Minas Gerais, Faculdade de Medicina,
Pós-graduação em Ciências da Saúde, Infectologia e Medicina Tropical, Belo Horizonte,
MG, Brasil
| | | | - Andréa Sobral de Almeida
- Fundação Oswaldo Cruz, Escola de Saúde Pública, Departamento de Doenças
Endêmicas, Rio de Janeiro, RJ, Brasil
| | - Paulo Chagastelles Sabroza
- Fundação Oswaldo Cruz, Escola de Saúde Pública, Departamento de Doenças
Endêmicas, Rio de Janeiro, RJ, Brasil
| | - Ilka Afonso Reis
- Universidade Federal de Minas Gerais, Instituto de Ciências Exatas,
Departamento de Estatística, Belo Horizonte, MG, Brasil
| | - Edelberto Santos Dias
- Fundação Oswaldo Cruz, Centro de Pesquisas René Rachou, Laboratório de
Leishmanioses, Belo Horizonte, MG, Brasil
| | - Mariângela Carneiro
- Universidade Federal de Minas Gerais, Faculdade de Medicina,
Pós-graduação em Ciências da Saúde, Infectologia e Medicina Tropical, Belo Horizonte,
MG, Brasil
- Universidade Federal de Minas Gerais, Instituto de Ciências Biológicas,
Departamento de Parasitologia, Belo Horizonte, MG, Brasil
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17
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Curi NHDA, Paschoal AMDO, Massara RL, Marcelino AP, Ribeiro AA, Passamani M, Demétrio GR, Chiarello AG. Factors associated with the seroprevalence of leishmaniasis in dogs living around Atlantic Forest fragments. PLoS One 2014; 9:e104003. [PMID: 25089629 PMCID: PMC4121198 DOI: 10.1371/journal.pone.0104003] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2014] [Accepted: 07/04/2014] [Indexed: 11/18/2022] Open
Abstract
Canine visceral leishmaniasis is an important zoonosis in Brazil. However, infection patterns are unknown in some scenarios such as rural settlements around Atlantic Forest fragments. Additionally, controversy remains over risk factors, and most identified patterns of infection in dogs have been found in urban areas. We conducted a cross-sectional epidemiological survey to assess the prevalence of leishmaniasis in dogs through three different serological tests, and interviews with owners to assess features of dogs and households around five Atlantic Forest remnants in southeastern Brazil. We used Generalized Linear Mixed Models and Chi-square tests to detect associations between prevalence and variables that might influence Leishmania infection, and a nearest neighbor dispersion analysis to assess clustering in the spatial distribution of seropositive dogs. Our findings showed an average prevalence of 20% (ranging from 10 to 32%) in dogs. Nearly 40% (ranging from 22 to 55%) of households had at least one seropositive dog. Some individual traits of dogs (height, sterilization, long fur, age class) were found to positively influence the prevalence, while some had negative influence (weight, body score, presence of ectoparasites). Environmental and management features (number of cats in the households, dogs with free-ranging behavior) also entered models as negative associations with seropositivity. Strong and consistent negative (protective) influences of the presence of chickens and pigs in dog seropositivity were detected. Spatial clustering of cases was detected in only one of the five study sites. The results showed that different risk factors than those found in urban areas may drive the prevalence of canine leishmaniasis in farm/forest interfaces, and that humans and wildlife risk infection in these areas. Domestic dog population limitation by gonadectomy, legal restriction of dog numbers per household and owner education are of the greatest importance for the control of visceral leishmaniasis in rural zones near forest fragments.
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Affiliation(s)
| | - Ana Maria de Oliveira Paschoal
- Postgraduate program in Ecology, Conservation and Management of Wildlife, Department of Biology, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte, Brazil
| | - Rodrigo Lima Massara
- Postgraduate program in Ecology, Conservation and Management of Wildlife, Department of Biology, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte, Brazil
| | | | | | - Marcelo Passamani
- Postgraduate program in Applied Ecology, Department of Biology, Federal University of Lavras, Lavras, Brazil
| | - Guilherme Ramos Demétrio
- Postgraduate program in Applied Ecology, Department of Biology, Federal University of Lavras, Lavras, Brazil
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Rêgo FD, Shimabukuro PHF, Quaresma PF, Coelho IR, Tonelli GB, Silva KMS, Barata RA, Dias ES, Gontijo CMF. Ecological aspects of the Phlebotominae fauna (Diptera: Psychodidae) in the Xakriabá Indigenous Reserve, Brazil. Parasit Vectors 2014; 7:220. [PMID: 24886717 PMCID: PMC4028289 DOI: 10.1186/1756-3305-7-220] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2014] [Accepted: 05/06/2014] [Indexed: 11/27/2022] Open
Abstract
Background Sand fly collections were performed to study ecological aspects of the Phlebotominae fauna of the Xakriabá Indigenous Reserve, an area with endemic cutaneous leishmaniasis, located in the state of Minas Gerais, Brazil. Methods The collections were performed in peridomicile areas and along trails previously selected for the study of wild and synanthropic Leishmania hosts. Differences in the distribution patterns of the sand fly species as well as in species richness and abundance between the different ecotopes were investigated during both rainy and dry seasons over the course of the study period. Results A total of 8,046 sand flies belonging to 11 genera and 28 species were collected. Lutzomyia longipalpis and Nyssomyia intermedia were the most abundant species in peridomicile areas, whereas Martinsmyia minasensis and Lutzomyia cavernicola were the most abundant species among the different trail ecotopes. Conclusion The different composition of the sand fly fauna observed in the peridomicile areas and in the trails during the study, reinforces the importance of sampled different areas in a phlebotomine fauna survey. The presence of Lutzomyia longipalpis and Ny. Intermedia most abundant in peridomicile can be important to Leishmania infantum and Leishmania braziliensis transmission in the Imbaúbas native village.
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Affiliation(s)
- Felipe Dutra Rêgo
- Grupo de Estudos em Leishmanioses, Centro de Pesquisas René Rachou, Fundação Oswaldo Cruz, Av, Augusto de Lima, 1715 Barro Preto, CEP 30190-002 Belo Horizonte, Minas Gerais, Brazil.
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Estimating the optimal control of zoonotic visceral leishmaniasis by the use of a mathematical model. ScientificWorldJournal 2013; 2013:810380. [PMID: 23990761 PMCID: PMC3748747 DOI: 10.1155/2013/810380] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2013] [Accepted: 07/09/2013] [Indexed: 11/18/2022] Open
Abstract
We argue that the strategy of culling infected dogs is not the most efficient way to control zoonotic visceral leishmaniasis (ZVL) and that, in the presence of alternative control strategies with better potential results, official programs of compulsory culling adopted by some countries are inefficient and unethical. We base our arguments on a mathematical model for the study of control strategies against ZVL, which allows the comparison of the efficacies of 5, alternative strategies. We demonstrate that the culling program, previously questioned on both theoretical and practical grounds is the less effective control strategy. In addition, we show that vector control and the use of insecticide-impregnated dog collars are, by far, more efficient at reducing the prevalence of ZVL in humans.
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Bray DP, Hamilton JGC. Insecticide-impregnated netting as a potential tool for long-lasting control of the leishmaniasis vector Lutzomyia longipalpis in animal shelters. Parasit Vectors 2013; 6:133. [PMID: 23642213 PMCID: PMC3658972 DOI: 10.1186/1756-3305-6-133] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2013] [Accepted: 04/30/2013] [Indexed: 11/23/2022] Open
Abstract
Background Leishmaniasis remains a serious neglected disease, with more than 350 million people potentially at risk worldwide. Control strategies often rely on spraying residual insecticides to target populations of the sand fly vectors that transmit Leishmania parasites when blood-feeding. These programmes are often difficult to sustain effectively, as sand fly resting sites must be resprayed on a regular basis. Here, we investigate whether application of insecticide-impregnated netting to a surface could act as an alternative to residual spraying for controlling the American visceral leishmaniasis vector Lutzomyia longipalpis. Methods Female L. longipalpis from our laboratory colony were exposed for 1 h to three treatments applied to plywood surfaces: 2% permethrin-impregnated netting (Olyset®), 20 mg a.i.m-2 micro-encapsulated lambda-cyhalothrin (Demand CS®) and a no-treatment control. We compared the speed at which these treatments acted, by measuring the percentage of sand flies killed both immediately after exposure to the treatment for 1 hour, as well as the number that had died 24 h after the 1 hour exposure. We repeated the experiment at 6 and 12 months following application to test the effectiveness of each treatment over time. Results When first applied, the lambda-cyhalothrin killed more sand flies in the first hour than the permethrin-impregnated netting. However, the effectiveness of the lambda-cyhalothrin diminished over time, so that there was no difference between the two treatments at 12 months. Both killed more sand flies than the control. When measured 24 h following exposure, both test treatments had killed close to 100% of sand flies when first applied, but while the lethal effect of the netting was maintained at close to 100% over 12 months, the effectiveness of the residual insecticide diminished to approximately 80% after 6 months. Conclusions The results of these initial laboratory experiments indicate that covering surfaces with insecticide impregnated netting material may provide a longer-lasting solution for killing sand flies than residual spraying. Field trials are needed to identify the feasibility of treating surfaces with netting or similar impregnated materials as part of a control program. In targeting L. longipalpis, the greatest benefits may be seen in treating animal sheds with netting, where these sand flies aggregate in large numbers, and which can be difficult to treat repeatedly by conventional spraying.
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Factors associated with visceral leishmaniasis in the americas: a systematic review and meta-analysis. PLoS Negl Trop Dis 2013; 7:e2182. [PMID: 23638203 PMCID: PMC3636096 DOI: 10.1371/journal.pntd.0002182] [Citation(s) in RCA: 70] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2012] [Accepted: 03/17/2013] [Indexed: 01/30/2023] Open
Abstract
Background Still today, more than 30 years after the beginning of the process of visceral leishmaniasis' urbanization, there is little knowledge about the risk factors for its occurrence, despite their relevance to the control and understanding of disease dynamics. The present study is the first systematic review with meta-analysis about factors associated with Leishmania infantum infection in humans in the Americas. Methods and Findings After searching different databases, consultations to the reference lists of articles and to experts in the field, 51 studies were reviewed. Theoretical discussions or meta-analysis of p-values or of effect sizes were used to pool information about each variable. The Q test and the I2 statistic were used to assess heterogeneities among the studies. Male sex was associated with visceral leishmaniasis in studies which used the leishmanin skin test for diagnosis and in those where the outcome was the clinical disease; the opposite occurred when serological diagnosis was applied. Younger individuals were less frequently infected than adults, but were more prone to illness. Although with different levels of evidence and of heterogeneity, the presence of dogs at home, higher dog seropositivity in nearby areas, lower socioeconomic status and highly vegetated areas were associated with L. infantum infection. This was not noticed for the presence of chickens in the house and with nutritional status. Susceptibilities to bias and limitations in the analysis and in the description of results were often identified in the studies analyzed. Conclusions Results showed the existence of consistent patterns for some of the factors analyzed and should be taken into account in developing more effective and well-targeted control measures. Studies must be conducted in new areas of the continent, with improved methodological quality and prioritizing the investigation of the patterns identified and their causes, as well as variables for which knowledge is poor. Visceral leishmaniasis (VL) is the most severe clinical form of leishmaniasis. In the Americas, VL is a zoonosis caused by the protozoan parasite Leishmania infantum, an intracellular micro-organism transmitted to humans through the bite of female phlebotomine sand flies. The domestic dog is considered the main reservoir and human beings are dead-end hosts. The disease occurs in 12 countries of the New World and Brazil accounts for 90% of the reported cases. The factors associated with infection are only partially understood, making harder understanding the disease dynamics and the development of effective and well-targeted control measures. Our work is the first systematic review with meta-analysis about factors associated with human visceral leishmaniasis in the Americas. It provides an organization of the available information, the description of more accurate data on the role of each of the factors studied, the evaluation of possible causes of heterogeneity in the results of the studies as well as the analysis of the quality of publications and limitations in the existing knowledge. The results of this study might be useful in the definition of which and where target interventions should be delivered, and for guiding researchers towards the development of future studies of better methodological quality.
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Chelbi I, Bray DP, Hamilton JGC. Courtship behaviour of Phlebotomus papatasi the sand fly vector of cutaneous leishmaniasis. Parasit Vectors 2012; 5:179. [PMID: 22935092 PMCID: PMC3480941 DOI: 10.1186/1756-3305-5-179] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2012] [Accepted: 07/20/2012] [Indexed: 11/10/2022] Open
Abstract
Background The sand fly Phlebotomus papatasi is an Old World vector of Leishmania major, the etiologic agent of zoonotic cutaneous leishmaniasis. This study describes the courtship behaviour of P. papatasi and compares it with that of Lutzomyia longipalpis, the New World vector of visceral leishmaniasis. Understanding the details of courtship behaviour in P. papatasi may help us to understand the role of sex pheromones in this important vector. Results P. papatasi courtship was found to start with the female touching the male, leading him to begin abdomen bending and wing flapping. Following a period of leg rubbing and facing, the male flaps his wings while approaching the female. The female then briefly flaps her wings in response, to indicate that she is willing to mate, thereby signaling the male to begin copulation. Male P. papatasi did not engage in parading behaviour, which is performed by male L. longipalpis to mark out individual territories during lekking (the establishment and maintenance of mating aggregations), or wing-flap during copulation, believed to function in the production of audio signals important to mate recognition. In P. papatasi the only predictor of mating success for males was previous copulation attempts and for females stationary wing-flapping. By contrast, male L. longipalpis mating success is predicted by male approach-flapping and semi-circling behaviour and for females stationary wing-flapping. Conclusions The results show that there are important differences between the mating behaviours of P. papatasi and L. longipalpis. Abdomen bending, which does not occur in L. longipalpis, may act in the release of sex pheromone from an as yet unidentified site in the male abdomen. In male L. longipalpis wing-flapping is believed to be associated with distribution of male pheromone. These different behaviours are likely to signify significant differences in how pheromone is used, an observation that is consistent with field and laboratory observations.
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Affiliation(s)
- Ifhem Chelbi
- Chemical Ecology Group, Institute for Science and Technology in Medicine, Keele University, Keele ST5 5BG, UK
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Jeraldo VDLS, Góes MADO, Casanova C, Melo CMD, Araújo EDD, Filho SPB, Cruz DER, Pinto MC. Sandfly fauna in an area endemic for visceral leishmaniasis in Aracaju, State of Sergipe, Northeast Brazil. Rev Soc Bras Med Trop 2012; 45:318-22. [DOI: 10.1590/s0037-86822012000300008] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2011] [Accepted: 03/23/2012] [Indexed: 11/22/2022] Open
Abstract
INTRODUCTION: In recent years, visceral leishmaniasis, a major public health problem, has been spreading from the rural to urban areas in many areas of Brazil, including Aracaju, the capital of the State of Sergipe. However, there are no studies of the sandfly fauna in this municipality or its variation over the year. METHODS: Phlebotomine sandflies were collected from a rural area of Aracaju from September 2007 to July 2009. Modified CDC ultra-violet (UV) light traps were used to evaluate sandfly monthly distribution and their presence in the domestic and peridomestic environments. RESULTS: The most abundant species was Lutzomyia longipalpis (90.4%) followed by Evandromyia lenti (9.6%). A chicken shed trap site had the highest proportion of L. longipalpis (51.1%) and large numbers of L. longipalpis were also collected in the houses closest to the chicken shed. There was a positive correlation between monthly rainfall and L. longipalpis abundance. CONCLUSIONS: Lutzomyia longipalpis is the most abundant species and is probably the main vector of the visceral leishmaniasis agent in the rural area of Aracaju. An increase in L. longipalpis frequency was observed during the rainy season. The peridomicile-intradomicile observations corroborate the importance of chicken sheds for the presence of L. longipalpis in the peridomestic environment. The great numbers of L. longipalpis inside the houses confirm the endophilic behaviour of this species and the possibility of visceral transmission in the intradomicile.
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Bigeli JG, Oliveira Júnior WPD, Teles NMM. Diagnosis of Leishmania (Leishmania) chagasi infection in dogs and the relationship with environmental and sanitary aspects in the municipality of Palmas, state of Tocantins, Brazil. Rev Soc Bras Med Trop 2012; 45:18-23. [DOI: 10.1590/s0037-86822012000100005] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2010] [Accepted: 08/08/2011] [Indexed: 11/22/2022] Open
Abstract
INTRODUCTION: The aim of the present study was to identify the presence of Leishmania (Leishmania) chagasi infection in dogs in the City of Palmas, Tocantins, Brazil, using the PCR technique to list the hot spots of infected dogs in the city and associate their occurrence to significant environmental changes at capture sites. METHODS: DNA was extracted from blood of dogs, and the PCR were performed with primers RV1/RV2. After screening the population studied, the regions of the city that had the highest occurrence of canine infection were detected. These sites were visited, and ecological parameters denoting anthropogenic disturbance were evaluated. RESULTS: Some important features were listed in the regions visited, such as low urbanization, lack of public collection of sewage, limited garbage collection, vacant lots with tall vegetation, decaying organic matter, and, most importantly, the occurrence of stray dogs and poultry in homes. CONCLUSIONS: The methodology for screening the population was very efficient, especially in evaluating a large number of individuals in a short time, with a high degree of automation. The results indicate an association between the observed parameters and the occurrence of infection in dogs. The model presented in the city is ideal for studies of disease progression and expansion and for the evaluation of control measures adopted for canine VL.
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Santini MS, Salomón OD, Acardi SA, Sandoval EA, Tartaglino L. Lutzomyia longipalpis behavior and control at an urban visceral leishmaniasis focus in Argentina. Rev Inst Med Trop Sao Paulo 2010; 52:187-91. [DOI: 10.1590/s0036-46652010000400004] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2010] [Accepted: 06/11/2010] [Indexed: 11/22/2022] Open
Abstract
During the earlier stages of visceral leishmaniasis transmission in Posadas City, Misiones, both the night activity and attraction to humans of Lutzomyia longipalpis were assessed, in order to provide preliminary recommendations. The impact of peridomestic deltamethrin spraying performed by local officials was also evaluated. Although Lu. longipalpis were found in traps located over a dog the entire night, 90% of the females were captured from 20.30h to 1.30h, and only landed on a human when he was at a distance of 1.5 m from the dog. Peridomestic spraying of deltamethrin (25 mg/m²) reduced the sand fly capture up to seven days post-intervention without dispersion in the border of the sprayed areas. These results support the recommendations about time-space focus of the protection measures: first half of the night, in the backyard, with pets and domestic animals kept at least 5 m from humans. The deltamethrin as it was used did not seem very effective in this scenario; neither did the eventual use of bed nets, at least in adults, due to the place/hour of sand fly higher activity. This study strengthens the need for a multidisciplinary approach to develop prevention strategies based both on biological and anthropological studies.
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Affiliation(s)
- Maria Soledad Santini
- Argentina, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas, Argentina
| | - Oscar Daniel Salomón
- Argentina, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas, Argentina
| | - Soraya Alejandra Acardi
- Universidad Nacional de Misiones, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas, Argentina
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Bray DP, Alves GB, Dorval ME, Brazil RP, Hamilton JG. Synthetic sex pheromone attracts the leishmaniasis vector Lutzomyia longipalpis to experimental chicken sheds treated with insecticide. Parasit Vectors 2010; 3:16. [PMID: 20222954 PMCID: PMC2850890 DOI: 10.1186/1756-3305-3-16] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2010] [Accepted: 03/11/2010] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Current strategies for controlling American visceral leishmaniasis (AVL) have been unable to prevent the spread of the disease across Brazil. With no effective vaccine and culling of infected dogs an unpopular and unsuccessful alternative, new tools are urgently needed to manage populations of the sand fly vector, Lutzomyia longipalpis Lutz and Neiva (Diptera: Psychodidae). Here, we test two potential strategies for improving L. longipalpis control using the synthetic sand fly pheromone (+/-)-9-methylgermacrene-B: the first in conjunction with spraying of animal houses with insecticide, the second using coloured sticky traps. RESULTS Addition of synthetic pheromone resulted in greater numbers of male and female sand flies being caught and killed at experimental chicken sheds sprayed with insecticide, compared to pheromone-less controls. Furthermore, a ten-fold increase in the amount of sex pheromone released from test sheds increased the number of females attracted and subsequently killed. Treating sheds with insecticide alone resulted in a significant decrease in numbers of males attracted to sheds (compared to pre-spraying levels), and a near significant decrease in numbers of females. However, this effect was reversed through addition of synthetic pheromone at the time of insecticide spraying, leading to an increase in number of flies attracted post-treatment.In field trials of commercially available different coloured sticky traps, yellow traps caught more males than blue traps when placed in chicken sheds. In addition, yellow traps fitted with 10 pheromone lures caught significantly more males than pheromone-less controls. However, while female sand flies showed a preference for both blue and yellow pheromone traps sticky traps over white traps in the laboratory, neither colour caught significant numbers of females in chicken sheds, either with or without pheromone. CONCLUSIONS We conclude that synthetic pheromone could currently be most effectively deployed for sand fly control through combination with existing insecticide spraying regimes. Development of a standalone pheromone trap remains a possibility, but such devices may require an additional attractive host odour component to be fully effective.
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Affiliation(s)
- Daniel P Bray
- Chemical Ecology Group, Institute of Science and Technology in Medicine, Keele University, ST5 5BG, Keele, UK.
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Stoddard ST, Morrison AC, Vazquez-Prokopec GM, Paz Soldan V, Kochel TJ, Kitron U, Elder JP, Scott TW. The role of human movement in the transmission of vector-borne pathogens. PLoS Negl Trop Dis 2009; 3:e481. [PMID: 19621090 PMCID: PMC2710008 DOI: 10.1371/journal.pntd.0000481] [Citation(s) in RCA: 342] [Impact Index Per Article: 22.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2009] [Accepted: 06/08/2009] [Indexed: 11/18/2022] Open
Abstract
Background Human movement is a key behavioral factor in many vector-borne disease systems because it influences exposure to vectors and thus the transmission of pathogens. Human movement transcends spatial and temporal scales with different influences on disease dynamics. Here we develop a conceptual model to evaluate the importance of variation in exposure due to individual human movements for pathogen transmission, focusing on mosquito-borne dengue virus. Methodology and Principal Findings We develop a model showing that the relevance of human movement at a particular scale depends on vector behavior. Focusing on the day-biting Aedes aegypti, we illustrate how vector biting behavior combined with fine-scale movements of individual humans engaged in their regular daily routine can influence transmission. Using a simple example, we estimate a transmission rate (R0) of 1.3 when exposure is assumed to occur only in the home versus 3.75 when exposure at multiple locations—e.g., market, friend's—due to movement is considered. Movement also influences for which sites and individuals risk is greatest. For the example considered, intriguingly, our model predicts little correspondence between vector abundance in a site and estimated R0 for that site when movement is considered. This illustrates the importance of human movement for understanding and predicting the dynamics of a disease like dengue. To encourage investigation of human movement and disease, we review methods currently available to study human movement and, based on our experience studying dengue in Peru, discuss several important questions to address when designing a study. Conclusions/Significance Human movement is a critical, understudied behavioral component underlying the transmission dynamics of many vector-borne pathogens. Understanding movement will facilitate identification of key individuals and sites in the transmission of pathogens such as dengue, which then may provide targets for surveillance, intervention, and improved disease prevention. Vector-borne diseases constitute a largely neglected and enormous burden on public health in many resource-challenged environments, demanding efficient control strategies that could be developed through improved understanding of pathogen transmission. Human movement—which determines exposure to vectors—is a key behavioral component of vector-borne disease epidemiology that is poorly understood. We develop a conceptual framework to organize past studies by the scale of movement and then examine movements at fine-scale—i.e., people going through their regular, daily routine—that determine exposure to insect vectors for their role in the dynamics of pathogen transmission. We develop a model to quantify risk of vector contact across locations people visit, with emphasis on mosquito-borne dengue virus in the Amazonian city of Iquitos, Peru. An example scenario illustrates how movement generates variation in exposure risk across individuals, how transmission rates within sites can be increased, and that risk within sites is not solely determined by vector density, as is commonly assumed. Our analysis illustrates the importance of human movement for pathogen transmission, yet little is known—especially for populations most at risk to vector-borne diseases (e.g., dengue, leishmaniasis, etc.). We outline several important considerations for designing epidemiological studies to encourage investigation of individual human movement, based on experience studying dengue.
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Affiliation(s)
- Steven T Stoddard
- Entomology, University of California, Davis, California, United States of America.
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New means of canine leishmaniasis transmission in north america: the possibility of transmission to humans still unknown. Interdiscip Perspect Infect Dis 2009; 2009:802712. [PMID: 19753139 PMCID: PMC2695953 DOI: 10.1155/2009/802712] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2009] [Accepted: 04/27/2009] [Indexed: 12/02/2022] Open
Abstract
At present it is not possible to determine in advance the outcome of Leishmania infantum infection. Canine Visceral Leishmaniasis (VL), caused by Le. infantum, is a natural disease process which offers a insight into the interaction of the host and resultant disease outcome. Canine VL results in the same altered pathophysiology and immunodysregulation seen in humans. VL in US dogs is likely to be transmitted primarily via nontraditional, nonvector means. VL mediated by Le. infantum is endemic in U.S. Foxhound dogs, with vertical transmission likely to be the novel primary means of transmission. This population of dogs offers an opportunity to identify host factors of natural disease. Prevention of human clinical visceral leishmaniasis can occur only by better understanding the disease ecology of the primary reservoir host: the dog.
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Bray DP, Hamilton JGC. Courtship behaviour in the sandfly Lutzomyia longipalpis, the New World vector of visceral leishmaniasis. MEDICAL AND VETERINARY ENTOMOLOGY 2007; 21:332-338. [PMID: 18092971 DOI: 10.1111/j.1365-2915.2007.00700.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Courtship behaviour in Lutzomyia longipalpis Lutz and Neiva (Diptera: Psychodidae) was examined to determine the sequence of behaviours that occur prior to copulation. Courtship consisted of a series of male and female touching and wing-flapping behaviours, with males performing a greater variety of wing-flapping behaviours than previously described. Occurrence of male approach-flapping, semi-circling and female stationary-flapping were all predictors of eventual copulation, and may coincide with the dispersal of pheromones or the production of auditory signals important to courtship. Touching occurred in the majority of observations, with contact most often made with the tips of the legs and antennae. This behaviour, not previously described in sandflies, was initiated by males and females, and may indicate the use of contact pheromones, a form of communication previously overlooked in L. longipalpis. Future studies are required to separate the auditory and chemical signals associated with wing-flapping, and to confirm whether L. longipalpis possesses cuticular hydrocarbons capable of inducing behavioural responses. The identification of signals that inhibit sexual behaviour during courtship may be particularly relevant to developing mating disruption techniques against L. longipalpis.
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Affiliation(s)
- D P Bray
- Chemical Ecology Group, Centre for Applied Entomology and Parasitology, Institute of Science and Technology in Medicine, Keele University, Keele, Staffordshire, U.K.
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Gouvêa MV, Werneck GL, Costa CHN, de Amorim Carvalho FA. Factors associated to Montenegro skin test positivity in Teresina, Brazil. Acta Trop 2007; 104:99-107. [PMID: 17825238 DOI: 10.1016/j.actatropica.2007.07.010] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2006] [Revised: 05/27/2007] [Accepted: 07/27/2007] [Indexed: 11/16/2022]
Abstract
Visceral leishmaniasis (VL) is an emerging infectious disease of urban areas in Brazil. To better understand this process, we have studied the association between reaction to the Montenegro skin test (MST), and demographic, socioeconomic and environmental factors in an urban area with high force of transmission. Associations between variables were expressed by prevalence ratios and their respective 95% confidence intervals estimated by using Poisson regression models with robust variance. Higher prevalence of positivity to MST was detected among male and older participants, and among subjects who owned dogs for 3 or more years. Individuals with higher literacy and living in households with three or more persons showed lower prevalence of MST reaction. These results suggest that the identification of high-risk groups might be feasible and useful for targeting interventions.
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Affiliation(s)
- Marcus Vinicius Gouvêa
- Núcleo de Estudos de Saúde Coletiva, Universidade Federal do Rio de Janeiro e Departamento de Epidemiologia, Instituto de Medicina Social, Universidade do Estado do Rio de Janeiro (UERJ), Rio de Janeiro, Brazil
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Courtenay O, Gillingwater K, Gomes PAF, Garcez LM, Davies CR. Deltamethrin-impregnated bednets reduce human landing rates of sandfly vector Lutzomyia longipalpis in Amazon households. MEDICAL AND VETERINARY ENTOMOLOGY 2007; 21:168-76. [PMID: 17550436 DOI: 10.1111/j.1365-2915.2007.00678.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
The entomological efficacy of using 25% deltamethrin EC insecticide-treated bednets (ITNs) was evaluated against the sandfly Lutzomyia longipalpis Lutz and Neiva (Diptera: Psychodidae), the principal vector of zoonotic visceral leishmaniasis (ZVL) in Latin America. A crossover field study in Amazon Brazil (Marajó Island, Pará State) demonstrated that, compared with untreated nets, the insecticide increased the barrier effect of nets by 39% (95% confidence interval [CI] 34-44%), reduced human landing rates by 80% (95% CI 62-90%) and increased the 24-h mortality rate from 0% to 98% (95% CI 93-99%) inside ITNs. The presence of an ITN also reduced the human landing rate on unprotected persons outside the net in the same room by 56% (95% CI 52-59%), and increased 24-h mortality to 68% (95% CI 62-73%) compared to 0.4% (0.1-2.0%) in untreated houses. The reduction in human landing rates in ITN rooms was associated with a doubling in the proportion of sandflies alighting on walls compared with that in untreated rooms, which was attributed to insecticide-induced excito-repellency. There was no evidence that sandflies were diverted onto unprotected hosts. Human landing catches inside houses peaked between 19.00 hours and 23.00 hours and declined steadily to zero at 02.00 hours and thereafter. House-to-house questionnaires established that only 34% of households owned at least one net (median two, range 1-8), only 20% of the population slept under a net (33% of 0-5-year-old children), and the majority (73%) of the population slept in hammocks. Combined data pertaining to sleeping times for children and sandfly activity period indicate that > 50% of sandfly bites inside houses, and substantially more outside houses, were taken before a third of children were potentially protected by a net. This study demonstrates the clear entomological efficacy of ITNs against Lu. longipalpis in this endemic region. The effectiveness of ITNs at preventing ZVL infection and disease has still to be evaluated.
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Affiliation(s)
- O Courtenay
- Ecology and Epidemiology Group, Department of Biological Sciences, University of Warwick, Coventry, UK.
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Alvar J, Yactayo S, Bern C. Leishmaniasis and poverty. Trends Parasitol 2006; 22:552-7. [PMID: 17023215 DOI: 10.1016/j.pt.2006.09.004] [Citation(s) in RCA: 502] [Impact Index Per Article: 27.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2006] [Revised: 08/30/2006] [Accepted: 09/21/2006] [Indexed: 12/01/2022]
Abstract
Leishmaniasis, a neglected tropical disease, has strong but complex links with poverty. The burden of leishmaniasis falls disproportionately on the poorest segments of the global population. Within endemic areas, increased infection risk is mediated through poor housing conditions and environmental sanitation, lack of personal protective measures and economically driven migration and employment that bring nonimmune hosts into contact with infected sand flies. Poverty is associated with poor nutrition and other infectious diseases, which increase the risk that a person (once infected) will progress to the clinically manifested disease. Lack of healthcare access causes delays in appropriate diagnosis and treatment and accentuates leishmaniasis morbidity and mortality, particularly in women. Leishmaniasis diagnosis and treatment are expensive and families must sell assets and take loans to pay for care, leading to further impoverishment and reinforcement of the vicious cycle of disease and poverty. Public investment in treatment and control would decrease the leishmaniasis disease burden and help to alleviate poverty.
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Affiliation(s)
- Jorge Alvar
- Communicable Diseases, Neglected Tropical Diseases Control, World Health Organization, 20 Ave Appia, CH-1211 Geneva 27, Switzerland.
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Werneck GL, Costa CHN, Walker AM, David JR, Wand M, Maguire JH. Multilevel modelling of the incidence of visceral leishmaniasis in Teresina, Brazil. Epidemiol Infect 2006; 135:195-201. [PMID: 16824254 PMCID: PMC2870576 DOI: 10.1017/s0950268806006881] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/25/2006] [Indexed: 11/05/2022] Open
Abstract
Epidemics of visceral leishmaniasis (VL) in major Brazilian cities are new phenomena since 1980. As determinants of transmission in urban settings probably operate at different geographic scales, and information is not available for each scale, a multilevel approach was used to examine the effect of canine infection and environmental and socio-economic factors on the spatial variability of incidence rates of VL in the city of Teresina. Details on an outbreak of greater than 1200 cases of VL in Teresina during 1993-1996 were available at two hierarchical levels: census tracts (socio-economic characteristics, incidence rates of human VL) and districts, which encompass census tracts (prevalence of canine infection). Remotely sensed data obtained by satellite generated environmental information at both levels. Data from census tracts and districts were analysed simultaneously by multilevel modelling. Poor socio-economic conditions and increased vegetation were associated with a high incidence of human VL. Increasing prevalence of canine infection also predicted a high incidence of human VL, as did high prevalence of canine infection before and during the epidemic. Poor socio-economic conditions had an amplifying effect on the association between canine infection and the incidence of human VL. Focusing interventions on areas with characteristics identified by multilevel analysis could be a cost-effective strategy for controlling VL. Because risk factors for infectious diseases operate simultaneously at several levels and ecological data usually are available at different geographical scales, multilevel modelling is a valuable tool for epidemiological investigation of disease transmission.
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Affiliation(s)
- G L Werneck
- Department of Immunology and Infectious Disease, Harvard School of Public Health, Boston, MA, USA.
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Resende MCD, Camargo MCV, Vieira JRM, Nobi RCA, Porto MN, Oliveira CDL, Pessanha JE, Cunha MDCM, Brandão ST. Seasonal variation of Lutzomyia longipalpis in Belo Horizonte, State of Minas Gerais. Rev Soc Bras Med Trop 2006; 39:51-5. [PMID: 16501767 DOI: 10.1590/s0037-86822006000100010] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Between October, 1997 and September, 1999 in Belo Horizonte, Minas Gerais a study of seasonal variation of Lutzomyia longipalpis was carried out in three distinct areas of the municipality. Sand flies were sampled at 15-day intervals in three residences, in each of which two CDC light traps were installed, one indoors and the other in the peridomicile. A total of 397 sand flies were captured in the three areas, with 65%, 30% and 1% of specimens collected in the eastern, northeast and Barreiro districts, respectively. The overall proportions of sand flies collected inside and around the houses were similar (57% vs 43%) and this pattern was seen for both Lutzomyia longipalpis and Lutzomyia whitmani . The highest population levels during the two years of the study were from October to March. From October onwards, numbers increased constantly until February. A gradual fall was seen from April onwards until the lowest levels were reached in the months of June, July and August.
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Lainson R, Rangel EF. Lutzomyia longipalpis and the eco-epidemiology of American visceral leishmaniasis, with particular reference to Brazil: a review. Mem Inst Oswaldo Cruz 2005; 100:811-27. [PMID: 16444411 DOI: 10.1590/s0074-02762005000800001] [Citation(s) in RCA: 301] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
An historical review is given of American visceral leishmaniasis (AVL), with particular reference to the eco-epidemiology of the disease in Brazil. Following the first records of AVL in this country, in 1934, the sandfly Lutzomyia longipalpis (Lutz and Neiva, 1912) was incriminated as the principal vector. It is now generally accepted, however, that there exist a number of cryptic species under the name of Lu. longipalpis s.l. and that variations in the quantity of the vasodilatory peptide maxadilan in the saliva of flies from different populations of Lu. longipalpis s.l., may account for the variable clinical manifestations of AVL seen in different geographic regions. Distribution of AVL has been shown to extend throughout most of South and Central America, with the domestic dog serving as the principal reservoir of infection for man. However, while one hypothesis suggests that the causative parasite is Leishmania infantum, imported from Europe with the Portuguese and Spanish colonists, the demonstration of a high rate of benign, inapparent infection in foxes in Amazonian Brazil raised an opposing suggestion that the parasite is indigenous to the Americas. Recent reports of similar infections in native marsupials, and possibly rodents, tend to support this view, particularly as Lu. longipalpis is primordially a silvatic sandfly. Although effective control measures in foci of the disease will diminish the number of canine and human infections, the presence of such an enzootic in a variety of native animals will render the total eradication of AVL unlikely.
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Affiliation(s)
- Ralph Lainson
- Departamento de Parasitologia, Instituto Evandro Chagas, Belém, PA, Brazil.
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Abstract
Analyses of contact-tracing data on the spread of infectious disease, combined with mathematical models, show that control measures require better knowledge of variability in individual infectiousness. From Typhoid Mary to SARS, it has long been known that some people spread disease more than others. But for diseases transmitted via casual contact, contagiousness arises from a plethora of social and physiological factors, so epidemiologists have tended to rely on population averages to assess a disease's potential to spread. A new analysis of outbreak data shows that individual differences in infectiousness exert powerful influences on the epidemiology of ten deadly diseases. SARS and measles (and perhaps avian influenza) show strong tendencies towards ‘superspreading events’ that can ignite explosive epidemics — but this same volatility makes outbreaks more likely to fizzle out. Smallpox and pneumonic plague, two potential bioterrorism agents, show steadier growth but still differ markedly from the traditional average-based view. These findings are relevant to how emerging diseases are detected and controlled.
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Affiliation(s)
- Alison P. Galvani
- the Department of Epidemiology and Public Health, Yale University School of Medicine, New Haven, 06520 Connecticut USA
| | - Robert M. May
- the Department of Zoology, University of Oxford, Oxford, OX1 3PS UK
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França-Silva JC, Barata RA, Costa RTD, Monteiro EM, Machado-Coelho GLL, Vieira EP, Prata A, Mayrink W, Nascimento E, Fortes-Dias CL, da Silva JC, Dias ES. Importance of Lutzomyia longipalpis in the dynamics of transmission of canine visceral leishmaniasis in the endemic area of Porteirinha Municipality, Minas Gerais, Brazil. Vet Parasitol 2005; 131:213-20. [PMID: 15975718 DOI: 10.1016/j.vetpar.2005.05.006] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2004] [Revised: 05/01/2005] [Accepted: 05/03/2005] [Indexed: 11/24/2022]
Abstract
A study of Lutzomyia longipalpis (Lutz and Neiva, 1912) (Diptera: Psychodidae), the primary vector of American visceral leishmaniasis (AVL), and the canine form of the disease, was carried out in Porteirinha. The city is situated in the northern part of the Brazilian State of Minas Gerais and is an endemic area of AVL. Systematic phlebotomine captures were performed in seven districts with previously reported cases of canine visceral leishmaniasis, during 2 years (January 2000--December 2001). A total of 2328 specimens of L. longipalpis were captured. The association between the local climate variables and the population density of L. longipalpis was evaluated and rainfall was determined to be a major factor, with increased populations during the rainy season (October--March). At the same time period, blood samples from every dog domiciled in the same seven districts, in total 14,077 animals, were analyzed for infection by viscerotropic Leishmania using indirect immunofluorescence assay (IFA). Accumulated incidence rates of canine VL per district varied from 3.40 to 14.34 for the 2-year period. A positive correlation between the population density of L. longipalpis and the canine cases of visceral leishmaniasis in Porteirinha was observed.
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Affiliation(s)
- João C França-Silva
- Departamento de Parasitologia, Universidade Federal de Minas Gerais, Av. Antônio Carlos 6627, CEP 31270-901, Belo Horizonte, MG, Brazil.
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38
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Costa CHN, Werneck GL, Rodrigues L, Santos MV, Araújo IB, Moura LS, Moreira S, Gomes RBB, Lima SS. Household structure and urban services: neglected targets in the control of visceral leishmaniasis. ANNALS OF TROPICAL MEDICINE AND PARASITOLOGY 2005; 99:229-36. [PMID: 15829132 DOI: 10.1179/136485905x28018] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Visceral leishmaniasis (VL) caused by Leishmania chagasi is a growing public-health problem in many parts of the New World. Although several studies have focused on the consequences of environmental damage, human migration and land occupation on the incidence of VL, the effects on the disease of the substandard living conditions that often result from the process of urbanization have not been investigated in detail. The present study was based in the Brazilian city of Teresina, where, since 1980, there have been two large outbreaks of VL (one in 1981-1985 and the other in 1993-1996), each involving at least 1000 newly reported cases. The role of household structure and the provision of urban services in the city, as predictors of the occurrence of VL, was studied in a case-control investigation. After controlling for age, crowding, and the background incidence of VL in the area where the subjects lived, the risk of acquiring the disease was found to be significantly higher for those who lived in houses with an inadequate sewage system and those who had no regular rubbish collection. Improving household structure and providing basic urban services might be effective strategies for controlling the spread of VL in urban areas.
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Affiliation(s)
- C H N Costa
- Instituto de Doenças Tropicais Nathan Portella and Universidade Federal do Piauí, Rua Governador Raimundo Artur de Vasconcelos, 151, CEP 64001-450, Teresina, PI, Brazil
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Alexander B, de Carvalho RL, McCallum H, Pereira MH. Role of the domestic chicken (Gallus gallus) in the epidemiology of urban visceral leishmaniasis in Brazil. Emerg Infect Dis 2002; 8:1480-5. [PMID: 12498667 PMCID: PMC2738513 DOI: 10.3201/eid0812.010485] [Citation(s) in RCA: 96] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Zoonotic visceral leishmaniasis (ZVL) is a serious public health problem in several Brazilian cities. Although the proximity of chicken houses is often cited as a risk factor in studies of urban ZVL, the role chickens play in the epidemiology of the disease has not been defined. Chickens attract both male and female sand flies (Lutzomyia longipalpis) but are unable to sustain Leishmania infections, and their presence may exert a zooprophylactic effect. We discuss environmental, physiologic, socioeconomic, and cultural factors related to chicken raising that could influence Le. infantum transmission in Brazilian cities and evaluate whether this practice significantly affects the risk of acquiring ZVL.
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40
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Soto SI, Lehmann T, Rowton ED, Vélez B ID, Porter CH. Speciation and population structure in the morphospecies Lutzomyia longipalpis (Lutz & Neiva) as derived from the mitochondrial ND4 gene. Mol Phylogenet Evol 2001; 18:84-93. [PMID: 11161745 DOI: 10.1006/mpev.2000.0863] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Recent studies have suggested that the phlebotomine sand fly Lutzomyia longipalpis (Diptera: Psychodidae), the principal vector of visceral leishmaniasis in the Neotropics, may consist of several allopatric sibling species. Phylogenetic and population genetic analyses of nucleotide variation in a 618-bp fragment of the mitochondrial ND4 gene were carried out on specimens of Lu. longipalpis from several locations in Central and South America. The analyses were concordant with previous findings, indicating that certain allopatric populations of Lu. longipalpis have become sufficiently differentiated as to represent sibling species. Phylogenetic analyses revealed deep genetic divisions between four clades represented by specimens from northern South America, Brazil, Central America, and an isolated Colombian population. Strong differentiation also was observed between certain populations within the first two clades. Partitioning of genetic diversity within and between Central American populations did not show the presence of more than one species in the region. However, distance, even within the 70-km range of the Honduran collection sites, was found to have a remarkably strong effect on gene flow. The highly subdivided population structure may be due to the patchiness of their distribution. F(ST) values comparing a Guatemalan population with several Honduran populations revealed a level of differentiation associated with a negligible rate of gene flow.
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Affiliation(s)
- S I Soto
- PECET, Universidad de Antioquia, Apartado 1226, Medellín, Colombia
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Abstract
This paper summarises the impact of different changes (environmental, ecological, developmental) on the one hand, with the impact of control measures on the other. The former group of changes have tended to exacerbate the incidence and prevalence of vector-borne parasitic diseases while the reduced public funds available for the health sector have reduced disease surveillance systems. However, some vector control/eradication programmes have been successful. Vector control in onchocerciasis and Chagas' disease and immediate host control in Guinea worm have reduced the public health importance of these disease. This contrasts, with malaria, where the complexity of different ecological situations and the variable vector ecology have made control difficult and epidemics frequent and unpredictable. Advances in our knowledge of how to implement and sustain insecticide-impregnated bednets which reduce morbidity and mortality in under 5-year olds will be a key issue for the coming years. In African trypanosomiasis and leishmaniasis, where control is dependent on effective diagnosis and surveillance followed by high-cost drug treatment, the health services are faced with major challenges--lack of drug availability and diagnostics no vector control--the diseases in some areas assuming epidemic status yet health services are unable to respond. Human African trypanosomiasis and visceral leishmaniasis are fatal if untreated, and require an emergency response approach. Changing vector distribution of Glossina is related to the ability of riverine flies of Glossina palpalis group to adapt to new vegetation patterns. In leishmaniasis changes have occurred in the distribution of the disease associated with development impact, urbanisation, civil unrest and changed agroforestry practice.
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Woolhouse ME, Dye C, Etard JF, Smith T, Charlwood JD, Garnett GP, Hagan P, Hii JL, Ndhlovu PD, Quinnell RJ, Watts CH, Chandiwana SK, Anderson RM. Heterogeneities in the transmission of infectious agents: implications for the design of control programs. Proc Natl Acad Sci U S A 1997; 94:338-42. [PMID: 8990210 PMCID: PMC19338 DOI: 10.1073/pnas.94.1.338] [Citation(s) in RCA: 787] [Impact Index Per Article: 29.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/1996] [Accepted: 10/07/1996] [Indexed: 02/03/2023] Open
Abstract
From an analysis of the distributions of measures of transmission rates among hosts, we identify an empirical relationship suggesting that, typically, 20% of the host population contributes at least 80% of the net transmission potential, as measured by the basic reproduction number, R0. This is an example of a statistical pattern known as the 20/80 rule. The rule applies to a variety of disease systems, including vector-borne parasites and sexually transmitted pathogens. The rule implies that control programs targeted at the "core" 20% group are potentially highly effective and, conversely, that programs that fail to reach all of this group will be much less effective than expected in reducing levels of infection in the population as a whole.
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Affiliation(s)
- M E Woolhouse
- Wellcome Trust Centre for the Epidemiology of Infectious Disease, Department of Zoology, University of Oxford, United Kingdom.
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Kelly DW, Mustafa Z, Dye C. Differential application of lambda-cyhalothrin to control the sandfly Lutzomyia longipalpis. MEDICAL AND VETERINARY ENTOMOLOGY 1997; 11:13-24. [PMID: 9061673 DOI: 10.1111/j.1365-2915.1997.tb00285.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
To study the impact of residual pyrethroid insecticide on the abundance and distribution of peridomestic Lutzomyia longipalpis, the sandfly vector of visceral leishmaniasis in Brazil, lambda-cyhalothrin was applied at 20 mg a.i.m-2 in the following interventions: (i) spraying of all animal pens in a village (blanket coverage); (ii) treatment of a subset of animal pens, either by spraying, or by installation of insecticide-impregnated 1 m2 cotton sheets as 'targets' (focal coverage). By sampling with CDC light traps, and using a novel analytical approach, we detected a 90% reduction in Lu.longipalpis abundance in sprayed sheds of the focal intervention. However, there was no discernible effect on the abundance of other phlebotomines trapped in sheds, or on the abundance of Lu.longipalpis in untreated dining-huts and houses. This differential impact on Lu.longipalpis abundance is explained in terms of the disruption of male pheromone production. Treated targets were approximately half as effective as residual spraying in reducing the abundance of Lu.longipalpis in sheds. Following blanket intervention, the abundance of Lu.longipalpis in traps fell by only 45% (not significant): catches at untreated dining-huts actually increased, possibly because the blanket coverage diverted Lu.longipalpis away from major aggregation sites at animal pens. It is recommended that care be taken during vector control programmes to ensure that all potential aggregation sites are treated. The possible consequences of leaving some sites untreated include poor control of peridomestic sandfly abundance and an increase in the biting rate on dogs and humans.
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Affiliation(s)
- D W Kelly
- London School of Hygiene and Tropical Medicine, U.K
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46
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Courtenay O, Macdonald DW, Lainson R, Shaw JJ, Dye C. Epidemiology of canine leishmaniasis: a comparative serological study of dogs and foxes in Amazon Brazil. Parasitology 1994; 109 ( Pt 3):273-9. [PMID: 7970884 DOI: 10.1017/s0031182000078306] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The paper describes a longitudinal field study of canine leishmaniasis in sympatric domestic dog and crab-eating fox (Cerdocyon thous) populations. Dogs were studied in house-to-house surveys, and foxes were studied by live-trapping and radio-telemetry. Because serological tests (IFAT in this case) for leishmaniasis are often of uncertain sensitivity and specificity, we draw conclusions comparatively. Both cross-sectional (age-prevalence) and longitudinal analyses indicate that incidence in dogs was highest in the dry season. Seasonal changes in the age-prevalence relationship for dogs suggest that serological conversion and recovery rates decline with prior exposure to infection, where 'recovery' may be due to loss of a positive antibody titre or death from leishmaniasis. The mean incidence in dogs was higher in the rural than in the urban population and higher in hunting dogs than pet dogs. Cross-sectional and longitudinal analyses of fox serological data suggest that foxes remain positive for longer than dogs on average, either because detectable antibody is more persistent or because they experience a lower mortality rate due to leishmaniasis.
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Affiliation(s)
- O Courtenay
- Department of Medical Parasitology, London School of Hygiene and Tropical Medicine, UK
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