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Vilas-Boas DF, Nakasone EKN, Gonçalves AAM, Lair DF, de Oliveira DS, Pereira DFS, Silva GG, Conrado IDSS, Resende LA, Zaldívar MF, Mariano RMDS, Dutra WO, Chávez-Fumagalli MA, Galdino AS, Silveira-Lemos D, Giunchetti RC. Global Distribution of Canine Visceral Leishmaniasis and the Role of the Dog in the Epidemiology of the Disease. Pathogens 2024; 13:455. [PMID: 38921753 PMCID: PMC11206782 DOI: 10.3390/pathogens13060455] [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: 03/26/2024] [Revised: 05/15/2024] [Accepted: 05/20/2024] [Indexed: 06/27/2024] Open
Abstract
Visceral leishmaniasis is a disease caused by protozoa of the species Leishmania (Leishmania) infantum (syn = Leishmania chagasi) and Leishmania (Leishmania) donovani, which are transmitted by hematophagous insects of the genera Lutzomyia and Phlebotomus. The domestic dog (Canis familiaris) is considered the main urban reservoir of the parasite due to the high parasite load on its skin, serving as a source of infection for sandfly vectors and, consequently, perpetuating the disease in the urban environment. Some factors are considered important in the perpetuation and spread of canine visceral leishmaniasis (CVL) in urban areas, such as stray dogs, with their errant behavior, and houses that have backyards with trees, shade, and organic materials, creating an attractive environment for sandfly vectors. CVL is found in approximately 50 countries, with the number of infected dogs reaching millions. However, due to the difficulty of controlling and diagnosing the disease, the number of infected animals could be even greater. In the four continents endemic for CVL, there are reports of disease expansion in endemic countries such as Brazil, Italy, Morocco, and Tunisia, as well as in areas where CVL is not endemic, for example, Uruguay. Socio-environmental factors, such as migration, drought, deforestation, and global warming, have been pointed out as reasons for the expansion into areas where it had been absent. Thus, the objective of this review is to address (i) the distribution of CVL in endemic areas, (ii) the role of the dog in the visceral leishmaniasis epidemiology and the factors that influence dog infection and the spread of the disease, and (iii) the challenges faced in the control of CVL.
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Affiliation(s)
- Diego Fernandes Vilas-Boas
- Laboratory of Biology of Cell Interactions, Institute of Biological Sciences, Department of Morphology, Federal University of Minas Gerais, Belo Horizonte 31270-901, MG, Brazil; (D.F.V.-B.); (E.K.N.N.); (A.A.M.G.); (D.F.L.); (D.S.d.O.); (D.F.S.P.); (G.G.S.); (I.d.S.S.C.); (L.A.R.); (M.F.Z.); (R.M.d.S.M.); (W.O.D.); (D.S.-L.)
| | - Eiji Kevin Nakasone Nakasone
- Laboratory of Biology of Cell Interactions, Institute of Biological Sciences, Department of Morphology, Federal University of Minas Gerais, Belo Horizonte 31270-901, MG, Brazil; (D.F.V.-B.); (E.K.N.N.); (A.A.M.G.); (D.F.L.); (D.S.d.O.); (D.F.S.P.); (G.G.S.); (I.d.S.S.C.); (L.A.R.); (M.F.Z.); (R.M.d.S.M.); (W.O.D.); (D.S.-L.)
| | - Ana Alice Maia Gonçalves
- Laboratory of Biology of Cell Interactions, Institute of Biological Sciences, Department of Morphology, Federal University of Minas Gerais, Belo Horizonte 31270-901, MG, Brazil; (D.F.V.-B.); (E.K.N.N.); (A.A.M.G.); (D.F.L.); (D.S.d.O.); (D.F.S.P.); (G.G.S.); (I.d.S.S.C.); (L.A.R.); (M.F.Z.); (R.M.d.S.M.); (W.O.D.); (D.S.-L.)
| | - Daniel Ferreira Lair
- Laboratory of Biology of Cell Interactions, Institute of Biological Sciences, Department of Morphology, Federal University of Minas Gerais, Belo Horizonte 31270-901, MG, Brazil; (D.F.V.-B.); (E.K.N.N.); (A.A.M.G.); (D.F.L.); (D.S.d.O.); (D.F.S.P.); (G.G.S.); (I.d.S.S.C.); (L.A.R.); (M.F.Z.); (R.M.d.S.M.); (W.O.D.); (D.S.-L.)
| | - Diana Souza de Oliveira
- Laboratory of Biology of Cell Interactions, Institute of Biological Sciences, Department of Morphology, Federal University of Minas Gerais, Belo Horizonte 31270-901, MG, Brazil; (D.F.V.-B.); (E.K.N.N.); (A.A.M.G.); (D.F.L.); (D.S.d.O.); (D.F.S.P.); (G.G.S.); (I.d.S.S.C.); (L.A.R.); (M.F.Z.); (R.M.d.S.M.); (W.O.D.); (D.S.-L.)
| | - Diogo Fonseca Soares Pereira
- Laboratory of Biology of Cell Interactions, Institute of Biological Sciences, Department of Morphology, Federal University of Minas Gerais, Belo Horizonte 31270-901, MG, Brazil; (D.F.V.-B.); (E.K.N.N.); (A.A.M.G.); (D.F.L.); (D.S.d.O.); (D.F.S.P.); (G.G.S.); (I.d.S.S.C.); (L.A.R.); (M.F.Z.); (R.M.d.S.M.); (W.O.D.); (D.S.-L.)
| | - Geralda Gabriele Silva
- Laboratory of Biology of Cell Interactions, Institute of Biological Sciences, Department of Morphology, Federal University of Minas Gerais, Belo Horizonte 31270-901, MG, Brazil; (D.F.V.-B.); (E.K.N.N.); (A.A.M.G.); (D.F.L.); (D.S.d.O.); (D.F.S.P.); (G.G.S.); (I.d.S.S.C.); (L.A.R.); (M.F.Z.); (R.M.d.S.M.); (W.O.D.); (D.S.-L.)
| | - Ingrid dos Santos Soares Conrado
- Laboratory of Biology of Cell Interactions, Institute of Biological Sciences, Department of Morphology, Federal University of Minas Gerais, Belo Horizonte 31270-901, MG, Brazil; (D.F.V.-B.); (E.K.N.N.); (A.A.M.G.); (D.F.L.); (D.S.d.O.); (D.F.S.P.); (G.G.S.); (I.d.S.S.C.); (L.A.R.); (M.F.Z.); (R.M.d.S.M.); (W.O.D.); (D.S.-L.)
| | - Lucilene Aparecida Resende
- Laboratory of Biology of Cell Interactions, Institute of Biological Sciences, Department of Morphology, Federal University of Minas Gerais, Belo Horizonte 31270-901, MG, Brazil; (D.F.V.-B.); (E.K.N.N.); (A.A.M.G.); (D.F.L.); (D.S.d.O.); (D.F.S.P.); (G.G.S.); (I.d.S.S.C.); (L.A.R.); (M.F.Z.); (R.M.d.S.M.); (W.O.D.); (D.S.-L.)
| | - Maykelin Fuentes Zaldívar
- Laboratory of Biology of Cell Interactions, Institute of Biological Sciences, Department of Morphology, Federal University of Minas Gerais, Belo Horizonte 31270-901, MG, Brazil; (D.F.V.-B.); (E.K.N.N.); (A.A.M.G.); (D.F.L.); (D.S.d.O.); (D.F.S.P.); (G.G.S.); (I.d.S.S.C.); (L.A.R.); (M.F.Z.); (R.M.d.S.M.); (W.O.D.); (D.S.-L.)
| | - Reysla Maria da Silveira Mariano
- Laboratory of Biology of Cell Interactions, Institute of Biological Sciences, Department of Morphology, Federal University of Minas Gerais, Belo Horizonte 31270-901, MG, Brazil; (D.F.V.-B.); (E.K.N.N.); (A.A.M.G.); (D.F.L.); (D.S.d.O.); (D.F.S.P.); (G.G.S.); (I.d.S.S.C.); (L.A.R.); (M.F.Z.); (R.M.d.S.M.); (W.O.D.); (D.S.-L.)
| | - Walderez Ornelas Dutra
- Laboratory of Biology of Cell Interactions, Institute of Biological Sciences, Department of Morphology, Federal University of Minas Gerais, Belo Horizonte 31270-901, MG, Brazil; (D.F.V.-B.); (E.K.N.N.); (A.A.M.G.); (D.F.L.); (D.S.d.O.); (D.F.S.P.); (G.G.S.); (I.d.S.S.C.); (L.A.R.); (M.F.Z.); (R.M.d.S.M.); (W.O.D.); (D.S.-L.)
| | - Miguel Angel Chávez-Fumagalli
- Computational Biology and Chemistry Research Group, Vicerrectorado de Investigación, Universidad Católica de Santa María, Arequipa 04000, Peru;
| | - Alexsandro Sobreira Galdino
- Microorganism Biotechnology Laboratory, Federal University of São João Del-Rei (UFSJ), Midwest Campus, Divinópolis 35501-296, MG, Brazil;
| | - Denise Silveira-Lemos
- Laboratory of Biology of Cell Interactions, Institute of Biological Sciences, Department of Morphology, Federal University of Minas Gerais, Belo Horizonte 31270-901, MG, Brazil; (D.F.V.-B.); (E.K.N.N.); (A.A.M.G.); (D.F.L.); (D.S.d.O.); (D.F.S.P.); (G.G.S.); (I.d.S.S.C.); (L.A.R.); (M.F.Z.); (R.M.d.S.M.); (W.O.D.); (D.S.-L.)
| | - Rodolfo Cordeiro Giunchetti
- Laboratory of Biology of Cell Interactions, Institute of Biological Sciences, Department of Morphology, Federal University of Minas Gerais, Belo Horizonte 31270-901, MG, Brazil; (D.F.V.-B.); (E.K.N.N.); (A.A.M.G.); (D.F.L.); (D.S.d.O.); (D.F.S.P.); (G.G.S.); (I.d.S.S.C.); (L.A.R.); (M.F.Z.); (R.M.d.S.M.); (W.O.D.); (D.S.-L.)
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Carvalho AG, Dias CLH, Blok DJ, Ignotti E, Luz JGG. Intra-urban differences underlying leprosy spatial distribution in central Brazil: geospatial techniques as potential tools for surveillance. GEOSPATIAL HEALTH 2023; 18. [PMID: 37902566 DOI: 10.4081/gh.2023.1227] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2023] [Accepted: 09/19/2023] [Indexed: 10/31/2023]
Abstract
This ecological study identified an aggregation of urban neighbourhoods spatial patterns in the cumulative new case detection rate (NCDR) of leprosy in the municipality of Rondonópolis, central Brazil, as well as intra-urban socioeconomic differences underlying this distribution. Scan statistics of all leprosy cases reported in the area from 2011 to 2017 were used to investigate spatial and spatiotemporal clusters of the disease at the neighbourhood level. The associations between the log of the smoothed NCDR and demographic, socioeconomic, and structural characteristics were explored by comparing multivariate models based on ordinary least squares (OLS) regression, spatial lag, spatial error, and geographically weighted regression (GWR). Leprosy cases were observed in 84.1% of the neighbourhoods of Rondonópolis, where 848 new cases of leprosy were reported corresponding to a cumulative NCDR of 57.9 cases/100,000 inhabitants. Spatial and spatiotemporal high-risk clusters were identified in western and northern neighbourhoods, whereas central and southern areas comprised low-risk areas. The GWR model was selected as the most appropriate modelling strategy (adjusted R²: 0.305; AIC: 242.85). By mapping the GWR coefficients, we identified that low literacy rate and low mean monthly nominal income per household were associated with a high NCDR of leprosy, especially in the neighbourhoods located within high-risk areas. In conclusion, leprosy presented a heterogeneous and peripheral spatial distribution at the neighbourhood level, which seems to have been shaped by intra-urban differences related to deprivation and poor living conditions. This information should be considered by decision-makers while implementing surveillance measures aimed at leprosy control.
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Affiliation(s)
- Amanda G Carvalho
- School of Medicine, Faculty of Health Sciences, Federal University of Rondonópolis, Rondonópolis, Brazil; Post-Graduation Program in Health Sciences, Faculty of Medicine, Federal University of Mato Grosso, Cuiabá.
| | - Carolina Lorraine H Dias
- School of Medicine, Faculty of Health Sciences, Federal University of Rondonópolis, Rondonópolis.
| | - David J Blok
- Department of Public Health, Erasmus MC, University Medical Center Rotterdam, Rotterdam.
| | - Eliane Ignotti
- Post-Graduation Program in Health Sciences, Faculty of Medicine, Federal University of Mato Grosso, Cuiabá, Brazil; Post-Graduation Program in Environmental Sciences, School of Health Sciences, State University of Mato Grosso, Cáceres.
| | - João Gabriel G Luz
- School of Medicine, Faculty of Health Sciences, Federal University of Rondonópolis, Rondonópolis.
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Carvalho AG, Kuhn ALM, Dias JVL, Luz JGG. Epidemiological patterns related to deaths caused by visceral leishmaniasis in the southern Amazon region of Brazil. Trans R Soc Trop Med Hyg 2022; 117:326-335. [PMID: 36479897 DOI: 10.1093/trstmh/trac110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2022] [Revised: 09/07/2022] [Accepted: 11/10/2022] [Indexed: 12/13/2022] Open
Abstract
ABSTRACT
Background
We analysed the spatial and spatiotemporal patterns of visceral leishmaniasis (VL) mortality at the municipality level in an endemic state in the southern Amazon region of Brazil. Individual-level factors associated with death due to VL were also investigated.
Methods
All VL cases and deaths reported between 2007 and 2018 were included. The global and local bivariate Moran's index assessed the space–time autocorrelation of smoothed triennial VL mortality. Kulldorff's scan statistics investigated spatial and spatiotemporal clusters. A multivariable logistic regression explored sociodemographic, diagnostic and clinical variables associated with death due to VL.
Results
We observed an overall VL mortality and lethality of 0.14 cases/100 000 inhabitants and 11.2%, respectively. A total of 14% of the municipalities registered at least one VL-related death. In the southeastern mesoregion of the state, we detected high-risk spatial (relative risk [RR] 14.14; p<0.001) and spatiotemporal (RR 15.91; p<0.001) clusters for VL mortality. Bivariate Moran's analysis suggested a high space–time autocorrelation of VL mortality. Death by VL was associated with age ≥48 y (odds ratio [OR] 7.2 [95% confidence interval {CI} 3.4 to 15.3]), displacement for notification (OR 3.3 [95% CI 1.5 to 7.2]) and occurrence of oedema (OR 2.8 [95% CI 1.3 to 6.1]) and bleeding (OR 5.8 [95% CI 2.6 to 12.8]).
Conclusions
VL mortality has a heterogeneous spatiotemporal distribution. The death-related factors suggest late diagnosis as an underlying cause of mortality.
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Affiliation(s)
- Amanda G Carvalho
- School of Medicine, Faculty of Health Sciences, Federal University of Rondonópolis , 5055 dos Estudantes Ave. Rondonópolis, Mato Grosso, 78736-900, Brazil
| | - André Luiz M Kuhn
- School of Medicine, Faculty of Health Sciences, Federal University of Rondonópolis , 5055 dos Estudantes Ave. Rondonópolis, Mato Grosso, 78736-900, Brazil
| | - João Victor L Dias
- School of Medicine, Federal University of Jequitinhonha and Mucuri Valleys , 1 Cruzeiro St. Teófilo Otoni, Minas Gerais, 39803-371, Brazil
| | - João Gabriel G Luz
- School of Medicine, Faculty of Health Sciences, Federal University of Rondonópolis , 5055 dos Estudantes Ave. Rondonópolis, Mato Grosso, 78736-900, Brazil
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Müller A, Montoya A, Escacena C, de la Cruz M, Junco A, Iriso A, Marino E, Fúster F, Miró G. Leishmania infantum infection serosurveillance in stray dogs inhabiting the Madrid community: 2007-2018. Parasit Vectors 2022; 15:96. [PMID: 35422058 PMCID: PMC9281004 DOI: 10.1186/s13071-022-05226-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Accepted: 02/26/2022] [Indexed: 11/21/2022] Open
Abstract
Background Leishmaniosis is an endemic zoonotic disease in the Mediterranean basin caused by Leishmania infantum and transmitted by phlebotomine sandflies. While in dogs disease may be severe, leishmaniosis is also a public health concern as was shown in the largest outbreak of human leishmaniosis (HL) in Europe in 2009 occurring in the Madrid region. The aim of the present study was to assess the applicability of the Leishmaniosis Surveillance Program (LeishSP) established in Madrid in 1996 by examining trends in L. infantum seroprevalence and associated epidemiological risk factors based on data for the 2007–2018 period. Methods The study population consisted of 3225 stray dogs from 17 animal shelters collaborating with the LeishSP. Seroprevalences were recorded twice annually (April and November) from 2007 to 2018. In each yearly period, a minimum of 100 dogs were tested to detect dogs infected before and after the sandfly risk season in Madrid area. Each dog was subjected to the same protocol of blood sample collection and clinical examination to collect epidemiological data and clinical signs. Anti-Leishmania-specific IgG was determined by IFAT cut-off ≥ 1:100. Results Overall seroprevalence was 6.1% (198 positive dogs). Epidemiological data indicate a significantly higher seroprevalence in dogs > 4 years old, purebred dogs (Pit Bull and related breeds), and medium to large size dogs. There were no seroprevalence differences according to sex and/or season (April and November). In addition, no significant differences were observed according to whether dogs lived inside or outside the HL outbreak area. Remarkably, of 198 dogs testing positive for L. infantum, 64.6% had no clinical signs, indicating a high proportion of clinically healthy infected dogs that could be a potential source of infection. Conclusions Results indicate a stable seroprevalence of L. infantum infection after 2006 in stray dogs in Madrid but with a recent slightly increasing trend. These observations support the need to continue with the LeishSP implemented by sanitary authorities of the Madrid Community as an early warning strategy for human and animal leishmaniosis and to enable continued assessment of the epidemiological role of dogs with subclinical infection in this important zoonotic disease. Graphical Abstract ![]()
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Affiliation(s)
- Aurora Müller
- Unidad Técnica 6 del Área de Salud Pública, Consejería de Sanidad, Comunidad de Madrid, Madrid, Spain
| | - Ana Montoya
- Departamento de Sanidad Animal, Facultad de Veterinaria, Universidad Complutense, Madrid, Spain
| | - Cristina Escacena
- Área de Vigilancia de Riesgos Ambientales en Salud, Consejería de Sanidad, Comunidad de Madrid, Madrid, Spain
| | - María de la Cruz
- Área de Vigilancia de Riesgos Ambientales en Salud, Consejería de Sanidad, Comunidad de Madrid, Madrid, Spain
| | - Ana Junco
- Área de Vigilancia de Riesgos Ambientales en Salud, Consejería de Sanidad, Comunidad de Madrid, Madrid, Spain
| | - Andrés Iriso
- Área de Vigilancia de Riesgos Ambientales en Salud, Consejería de Sanidad, Comunidad de Madrid, Madrid, Spain
| | - Eloy Marino
- Unidad Técnica 1-4-7 del Área de Salud Pública, Consejería de Sanidad, Comunidad de Madrid, Madrid, Spain
| | - Fernando Fúster
- Área de Vigilancia de Riesgos Ambientales en Salud, Consejería de Sanidad, Comunidad de Madrid, Madrid, Spain
| | - Guadalupe Miró
- Departamento de Sanidad Animal, Facultad de Veterinaria, Universidad Complutense, Madrid, Spain.
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Luz JGG, de Carvalho AG, Dias JVL, Marciano LCL, de Vlas SJ, Fontes CJF, Coffeng LE. Passive case detection for canine visceral leishmaniasis control in urban Brazil: Determinants of population uptake. PLoS Negl Trop Dis 2021; 15:e0009818. [PMID: 34624032 PMCID: PMC8528332 DOI: 10.1371/journal.pntd.0009818] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Revised: 10/20/2021] [Accepted: 09/17/2021] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND In Brazil, the transmission of Leishmania infantum in urban settings is closely related to infection among dogs, with occasional transmission to humans. Serological screening of dogs for Leishmania spp. infection on requests of their owners (passive case detection) represents a frequent, but little studied, practice within the scope of Brazilian public health. This study identified factors associated with canine visceral leishmaniasis (CVL) diagnosis-seeking behavior of dog owners in Rondonópolis (236,000 inhabitants), a municipality in Central-Western Brazil where VL is endemic. Also, we evaluated the profile of dog owners and their animals screened on free demand. METHODOLOGY/PRINCIPAL FINDINGS Using mixed effects negative binomial regression, we modelled the number of dogs screened for Leishmania infection on free demand per neighborhood from 2011 to 2016 as a function of time-dependent predictors (current or recent canine seropositivity and human VL incidence), distance to the screening site, and demographic variables. We assessed potential delays in the effect of time-dependent predictors on the outcome. Among 12,536 dogs screened for Leishmania infection, 64.2% were tested during serosurveys and 35.8% were tested on free demand. Of these, 63.9% were positive. Uptake of screening under free demand was strongly associated with higher levels of canine seropositivity in the neighborhood (current or recent) and decreasing distance to the screening site. A subsample of dog owners (n = 93) who sought CVL screening between 2016 and 2017 were interviewed in more detail. Owners with better socioeconomic status and dogs with apparent CVL clinical manifestations prevailed among them. CONCLUSIONS/SIGNIFICANCE To support timely CVL management, passive case detection along with awareness activities aimed at dog owners should be encouraged in endemic areas. Screening sites should be prioritized in accessible zones, as well as in socio-economically disadvantage areas. In parallel, CVL active case detection should be continued as a surveillance tool to guide control actions.
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Affiliation(s)
- João Gabriel G. Luz
- Department of Public Health, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands
- School of Medicine, Institute of Exact and Natural Sciences, Federal University of Rondonópolis, Rondonópolis, Brazil
- Post-graduation Program in Health Sciences, Faculty of Medicine, Federal University of Mato Grosso, Cuiabá, Brazil
| | - Amanda G. de Carvalho
- School of Medicine, Institute of Exact and Natural Sciences, Federal University of Rondonópolis, Rondonópolis, Brazil
- Post-graduation Program in Health Sciences, Faculty of Medicine, Federal University of Mato Grosso, Cuiabá, Brazil
| | - João Victor L. Dias
- School of Medicine, Federal University of Jequitinhonha and Mucuri Valleys, Teófilo Otoni, Brazil
| | - Luis Claudio L. Marciano
- School of Medicine, Institute of Exact and Natural Sciences, Federal University of Rondonópolis, Rondonópolis, Brazil
| | - Sake J. de Vlas
- Department of Public Health, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Cor Jesus F. Fontes
- Post-graduation Program in Health Sciences, Faculty of Medicine, Federal University of Mato Grosso, Cuiabá, Brazil
| | - Luc E. Coffeng
- Department of Public Health, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands
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Silva DAD, Bonatto NCM, Venturin GL, Melo LM, Oliveira PLD, Costa LR, Bosculo MRM, Barros LDD, Lima VMFD, Almeida BFMD. Epidemiology of canine visceral leishmaniasis in a vulnerable region in Brazil. REVISTA BRASILEIRA DE PARASITOLOGIA VETERINARIA = BRAZILIAN JOURNAL OF VETERINARY PARASITOLOGY : ORGAO OFICIAL DO COLEGIO BRASILEIRO DE PARASITOLOGIA VETERINARIA 2021; 30:e009921. [PMID: 34495125 DOI: 10.1590/s1984-29612021075] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Accepted: 08/12/2021] [Indexed: 06/13/2023]
Abstract
Visceral leishmaniasis (VL) is a neglected and endemic zoonosis that occurs throughout Brazil; nevertheless, few studies have focused on the early detection of the disease. The municipality of Ourinhos is a non-receptive, silent and vulnerable area for VL, where the seroprevalence of this disease has so far not been investigated. The present study aimed to determine the seroprevalence of canine VL in Ourinhos-SP, and to identify the presence of risk factors. Blood samples were obtained from 604 dogs during a rabies vaccination campaign together with application of a socioeconomic questionnaire, environmental and animal characteristics and tutor's knowledge about the disease. The samples were subjected to indirect ELISA and new samples were collected from reactive and suspect animals, including whole blood and lymph node aspiration evaluated by parasitological method, complete blood count and PCR. No animal was diagnosed as positive based on the combination of direct and indirect tests and the tutors' answers indicated little knowledge about leishmaniasis, being often confused with other diseases transmitted by arthropods; hence, according to the proposed methods, the presence of canine leishmaniasis in the city of Ourinhos was not confirmed and health education campaigns about the disease should be carried out.
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Affiliation(s)
- Douglas Aparecido da Silva
- Laboratório de Protozoologia Animal, Departamento de Medicina Veterinária Preventiva, Universidade Estadual de Londrina -UEL, Londrina, PR, Brasil
| | - Natália Camila Minucci Bonatto
- Laboratório Clínico Veterinário, Departamento de Medicina Veterinária Preventiva, Universidade Estadual de Londrina - UEL, Londrina, PR, Brasil
| | - Gabriela Lovizutto Venturin
- Laboratório de Imunologia, Departamento de Clínica, Cirurgia e Reprodução Animal, Universidade Estadual Paulista - UNESP, Campus Araçatuba, Araçatuba, SP, Brasil
| | - Larissa Martins Melo
- Laboratório de Imunologia, Departamento de Clínica, Cirurgia e Reprodução Animal, Universidade Estadual Paulista - UNESP, Campus Araçatuba, Araçatuba, SP, Brasil
| | - Paula Lima de Oliveira
- Laboratório de Imunologia, Departamento de Clínica, Cirurgia e Reprodução Animal, Universidade Estadual Paulista - UNESP, Campus Araçatuba, Araçatuba, SP, Brasil
- Hospital Veterinário Roque Quagliato, Departamento de Medicina Veterinária, Centro Universitário das Faculdades Integradas de Ourinhos - Uni, Ourinhos, SP, Brasil
| | - Letícia Ramos Costa
- Hospital Veterinário Roque Quagliato, Departamento de Medicina Veterinária, Centro Universitário das Faculdades Integradas de Ourinhos - Uni, Ourinhos, SP, Brasil
| | - Maria Rachel Melo Bosculo
- Hospital Veterinário Roque Quagliato, Departamento de Medicina Veterinária, Centro Universitário das Faculdades Integradas de Ourinhos - Uni, Ourinhos, SP, Brasil
| | - Luiz Daniel de Barros
- Laboratório de Protozoologia Animal, Departamento de Medicina Veterinária Preventiva, Universidade Estadual de Londrina -UEL, Londrina, PR, Brasil
| | - Valéria Marçal Felix de Lima
- Laboratório de Imunologia, Departamento de Clínica, Cirurgia e Reprodução Animal, Universidade Estadual Paulista - UNESP, Campus Araçatuba, Araçatuba, SP, Brasil
| | - Breno Fernando Martins de Almeida
- Laboratório de Imunologia, Departamento de Clínica, Cirurgia e Reprodução Animal, Universidade Estadual Paulista - UNESP, Campus Araçatuba, Araçatuba, SP, Brasil
- Hospital Veterinário Roque Quagliato, Departamento de Medicina Veterinária, Centro Universitário das Faculdades Integradas de Ourinhos - Uni, Ourinhos, SP, Brasil
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Luz JGG, Dias JVL, Carvalho AG, Piza PA, Chávez-Pavoni JH, Bulstra C, Coffeng LE, Fontes CJF. Human visceral leishmaniasis in Central-Western Brazil: Spatial patterns and its correlation with socioeconomic aspects, environmental indices and canine infection. Acta Trop 2021; 221:105965. [PMID: 34029529 DOI: 10.1016/j.actatropica.2021.105965] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2021] [Revised: 05/05/2021] [Accepted: 05/15/2021] [Indexed: 10/21/2022]
Abstract
In this ecological study, we investigated spatial patterns of human visceral leishmaniasis (VL) incidence, its correlation with socioeconomic aspects, environmental indices (obtained through remote sensing) and canine VL during 2011-2016 in the municipality of Rondonópolis, a relevant endemic area for VL in Central-Western Brazil. Human VL cases were georeferenced and point patterns were analyzed by univariate Ripley's K function and Kernel density estimation (KDE). Poisson-based scan statistics were used to investigate spatial and spatiotemporal clusters of human VL incidence at the neighborhood level. Socioeconomic and environmental characteristics were compared between neighborhoods within and outside spatial human VL clusters. Also, we assessed the correlation between smoothed human VL incidence and canine VL seropositivity rates within and between neighborhoods. Human VL cases were clustered up to 2000 m; four hotspots were identified by KDE in peripheral areas. Spatial and spatiotemporal low-risk clusters for human VL were identified in central and southern areas. Neighborhoods within spatial low-risk cluster presented higher mean income, literacy rate, sanitary sewage service coverage and lower altitude, compared to the rest of the municipality. A positive correlation was found between the occurrence of human and canine VL. On the northern outskirts, high human VL incidence was spatially correlated with high canine VL seropositivity in surrounding neighborhoods. In conclusion, human VL demonstrated a heterogeneous, aggregated and peripheral spatial pattern. This distribution was correlated with intra-urban socioeconomic differences and canine VL seropositivity at the neighborhood level.
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Matsumoto PSS, Hiramoto RM, Pereira VBR, Camprigher VM, Taniguchi HH, de Raeffray Barbosa JE, Cortez LRPDB, Fonseca EDS, Guimarães RB, Tolezano JE. Impact of the dog population and household environment for the maintenance of natural foci of Leishmania infantum transmission to human and animal hosts in endemic areas for visceral leishmaniasis in Sao Paulo state, Brazil. PLoS One 2021; 16:e0256534. [PMID: 34464421 PMCID: PMC8407543 DOI: 10.1371/journal.pone.0256534] [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: 05/13/2021] [Accepted: 08/09/2021] [Indexed: 11/20/2022] Open
Abstract
When it comes to visceral leishmaniasis (VL) in Brazil, one of the main targets of public health policies of surveillance is the control of domestic canine reservoirs of Leishmania infantum. This paper aims to evaluate the effect of the dog population and household environment for the maintenance of natural foci in the transmission to human and animal hosts in an endemic city for VL, Bauru, in Brazil. We collected 6,578 blood samples of dogs living in 3,916 households from Nov.2019 to Mar.2020 and applied geospatial models to predict the disease risk based on the canine population. We used Kernel density estimation, cluster analysis, geostatistics, and Generalized Additive Models (GAM). To validate our models, we used cross-validation and created a receiver operating characteristic (ROC) curve. We found an overall canine VL (CVL) seroprevalence of 5.6% for the sampled dogs, while for the households, the positivity rate was 8.7%. Odds ratios (OR) for CVL increased progressively according to the number of canines for >2 dogs (OR 2.70); households that already had CVL in the past increased the chances for CVL currently (OR 2.73); and the cases of CVL increase the chances for human VL cases (OR 1.16). Our models were statistically significant and demonstrated a spatial association between canine and human disease cases, mainly in VL foci that remain endemic. Although the Kernel density ratio map had the best performance (AUC = 82), all the models showed high risk in the city's northwest area. Canine population dynamics must be considered in public policies, and geospatial methods may help target priority areas and planning VL surveillance in low and middle-income countries.
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Affiliation(s)
| | | | | | | | | | | | | | | | - Raul Borges Guimarães
- Department of Geography, Sao Paulo State University/Faculty of Sciences and Technology (FCT/UNESP), Presidente Prudente, Sao Paulo, Brazil
| | - José Eduardo Tolezano
- Parasitology and Mycology Center, Adolfo Lutz Institute (IAL), Sao Paulo, Sao Paulo, Brazil
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de Carvalho AG, Alves I, Borges LM, Spessatto LB, Castro LS, Luz JGG. Basic knowledge about visceral leishmaniasis before and after educational intervention among primary health care professionals in Midwestern Brazil. Rev Inst Med Trop Sao Paulo 2021; 63:e56. [PMID: 34231821 PMCID: PMC8266306 DOI: 10.1590/s1678-9946202163056] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Accepted: 06/18/2021] [Indexed: 11/21/2022] Open
Abstract
Health education and training of primary health care (PHC) professionals are highly recommended to reduce the occurrence and lethality of visceral leishmaniasis (VL). This study assessed the impact of an educational intervention on the basic knowledge about visceral leishmaniasis (VL) among PHC professionals from the Brazilian municipality of Rondonopolis, an important endemic area for VL. Responses provided by physicians, nurses, nursing technicians and community health agents from 12 PHC facilities were recorded through the application of self-completed and semi-structured questionnaires before (n=92) and after (n=64) an in-person health training course covering various aspects of VL. Closed- and open-ended responses were compared by the chi-square test and analyses of word clouds, respectively. The proportion of professionals aware of the correct etiological agent (p<0.001) and transmission route (p<0.001) of VL increased post-intervention. In addition, they increased their ability to recognize fever (p<0.001), weakness (p<0.001), weight loss (p<0.001), pallor (p<0.001) and abdominal distention (p=0.013) as clinical manifestations of human VL, and weakness (p<0.001), alopecia (p<0.001) and weight loss (p=0.019) as signs of canine VL. Analyses of word clouds suggested that the participants became more aware of the role of dogs in VL transmission and the role of environmental management in the prevention of VL. In conclusion, the intervention positively impacted the baseline knowledge concerning VL among the professionals. This can support the planning of educational activities for the PHC team regarding early case detection, prevention and control of VL in endemic areas.
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Affiliation(s)
- Amanda Gabriela de Carvalho
- Universidade Federal de Rondonópolis, Instituto de Ciências Exatas e
Naturais, Curso de Medicina, Rondonópolis, Mato Grosso, Brazil
| | - Isaac Alves
- Universidade Federal de Rondonópolis, Instituto de Ciências Exatas e
Naturais, Curso de Medicina, Rondonópolis, Mato Grosso, Brazil
| | - Larissa Marquiori Borges
- Universidade Federal de Rondonópolis, Instituto de Ciências Exatas e
Naturais, Curso de Medicina, Rondonópolis, Mato Grosso, Brazil
| | - Laura Bordignon Spessatto
- Universidade Federal de Rondonópolis, Instituto de Ciências Exatas e
Naturais, Programa de Residência Multiprofissional em Saúde da Família,
Rondonópolis, Mato Grosso, Brazil
| | - Ludiele Souza Castro
- Universidade Federal de Rondonópolis, Instituto de Ciências Exatas e
Naturais, Curso de Medicina, Rondonópolis, Mato Grosso, Brazil
- Universidade Federal de Rondonópolis, Instituto de Ciências Exatas e
Naturais, Programa de Residência Multiprofissional em Saúde da Família,
Rondonópolis, Mato Grosso, Brazil
| | - João Gabriel Guimarães Luz
- Universidade Federal de Rondonópolis, Instituto de Ciências Exatas e
Naturais, Curso de Medicina, Rondonópolis, Mato Grosso, Brazil
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Luz JGG, Carvalho AG, Naves DB, Dias JVL, Fontes CJF. Are backyard characteristics relevant factors for the occurrence of human visceral leishmaniasis in Central-Western Brazil? Trans R Soc Trop Med Hyg 2021; 114:276-283. [PMID: 31851365 DOI: 10.1093/trstmh/trz110] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Revised: 09/01/2019] [Accepted: 10/17/2019] [Indexed: 01/20/2023] Open
Abstract
BACKGROUND This retrospective case-control study aimed to investigate the factors associated with the occurrence of human visceral leishmaniasis (VL) in the municipality of Rondonópolis, which is a highly endemic area for VL in Central-Western Brazil. METHODS All VL cases reported in Rondonópolis from 2011 to 2016 were included. For each case, two neighborhood- and age-matched controls with the absence of past and present history of VL and negative rk39-based immunochromatographic test, were recruited. Data were retrospectively collected through interviews that assessed socioeconomic aspects, housing features, backyard characteristics, presence of animals and daily habits. A multivariate conditional logistic regression analysis was used to identify factors associated with human VL. RESULTS During the study period, 81 VL cases were reported in Rondonópolis, of which 37 (45.7%) were included in this study. Seventy controls were also included. The variables associated with VL occurrence were the outdoor location of a bathroom and/or kitchen separated from the rest of the house (OR 7.8; 95% CI 2.1 to 29.5), the presence of a vegetable garden (OR 5.3; 95% CI 1.3 to 21.2) and the presence of decaying fruits (OR 10.7; 95% CI 2.0 to 52.1) in the backyard. CONCLUSIONS Our findings suggest an association between backyard characteristics and VL. This may be useful in guiding preventive and control measures against zoonotic VL worldwide.
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Affiliation(s)
- João Gabriel Guimarães Luz
- School of Medicine, Institute of Exact and Natural Sciences, Federal University of Mato Grosso (UFMT), 5055 dos Estudantes Ave. Rondonópolis, Mato Grosso, 78735-901, Brazil.,School of Medicine, Post-Graduation Program in Health Sciences, Federal University of Mato Grosso (UFMT), 2367 Fernando Corrêa da Costa Ave. Cuiabá, Mato Grosso, 78060-900, Brazil
| | - Amanda Gabriela Carvalho
- School of Medicine, Institute of Exact and Natural Sciences, Federal University of Mato Grosso (UFMT), 5055 dos Estudantes Ave. Rondonópolis, Mato Grosso, 78735-901, Brazil.,School of Medicine, Post-Graduation Program in Health Sciences, Federal University of Mato Grosso (UFMT), 2367 Fernando Corrêa da Costa Ave. Cuiabá, Mato Grosso, 78060-900, Brazil
| | - Danilo Bueno Naves
- School of Medicine, Institute of Exact and Natural Sciences, Federal University of Mato Grosso (UFMT), 5055 dos Estudantes Ave. Rondonópolis, Mato Grosso, 78735-901, Brazil
| | - João Victor Leite Dias
- School of Medicine, Federal University of Jequitinhonha and Mucuri Valleys (UFVJM), 1 Cruzeiro St. Teófilo Otoni, Minas Gerais, 39803-371, Brazil
| | - Cor Jesus Fernandes Fontes
- School of Medicine, Post-Graduation Program in Health Sciences, Federal University of Mato Grosso (UFMT), 2367 Fernando Corrêa da Costa Ave. Cuiabá, Mato Grosso, 78060-900, Brazil.,School of Medicine, Faculty of Biomedical Sciences of Cacoal (FACIMED), 3087 Cuiabá Ave. Cacoal, Rondônia, 76963-665, Brazil
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11
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Silva RBS, Franco-Silva LF, Lima DA, Freitas ABADA, Ramalho WM, Melo MAD. Spatial analysis of canine leishmaniasis in an area of transmission of the semi-arid region of the State of Paraíba, Brazil. ACTA ACUST UNITED AC 2021; 30:e018620. [PMID: 33533796 DOI: 10.1590/s1984-296120201089] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Accepted: 11/30/2020] [Indexed: 11/22/2022]
Abstract
Visceral leishmaniasis is a widely distributed zoonosis and canine infection is an important indicator of risk for the occurrence of the disease in humans. The goal of this analysis was to study the spatial clustering of canine leishmaniasis (CL) in the municipality of Santa Luzia, state of Paraíba. For this, 749 samples of canine plasma were tested using three serological tests. The dog was considered positive if it reacted in two serological tests. The location of the residences was performed with a Global Positioning System receiver (GPS Garmin® eTrex 30), and used to perform georeferencing and spatial analysis. The prevalence of CL was 15.49% and it was observed that most cases of the urban area were concentrated in the Frei Damião neighborhood, on the outskirts of the city, where a high-risk cluster for the occurrence of the disease was formed (p = 0.02; RR = 2.48). No statistically significant cluster was observed in rural areas. CL is widely distributed in the municipality of Santa Luzia in a heterogeneous manner and with a tendency to urbanization. The areas identified with high prevalence and highest risk should be prioritized to maximize the efficiency of the Visceral Leishmaniasis Surveillance and Control Program and minimize the chance of new canine and human cases.
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Affiliation(s)
- Raizza Barros Sousa Silva
- Pós-graduação em Ciência e Saúde Animal, Universidade Federal de Campina Grande - UFCG, Patos, PB, Brasil
| | - Laysa Freire Franco-Silva
- Pós-graduação em Ciência e Saúde Animal, Universidade Federal de Campina Grande - UFCG, Patos, PB, Brasil
| | - Diana Azevedo Lima
- Unidade Acadêmica de Medicina Veterinária, Universidade Federal de Campina Grande - UFCG, Patos, PB, Brasil
| | | | | | - Marcia Almeida de Melo
- Pós-graduação em Ciência e Saúde Animal, Universidade Federal de Campina Grande - UFCG, Patos, PB, Brasil
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12
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Abuzaid AA, Aldahan MA, Helal MAA, Assiri AM, Alzahrani MH. Visceral leishmaniasis in Saudi Arabia: From hundreds of cases to zero. Acta Trop 2020; 212:105707. [PMID: 32950481 DOI: 10.1016/j.actatropica.2020.105707] [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: 07/23/2020] [Revised: 09/10/2020] [Accepted: 09/10/2020] [Indexed: 10/23/2022]
Abstract
The kingdom of Saudi Arabia (KSA) has succeeded in bringing the reported numbers of Visceral leishmaniasis (VL) cases from hundreds during the 1980s and 1990s to zero case in 2019. The endemicity of VL has been confined mainly to the Southwest regions, namely Jazan and Aseer regions. Leishmania donovani species have been identified as the causative species of VL, while L. infantum have been isolated only from dogs in the endemic areas. Many species of sand flies were caught in Southwest, but P. orientalis is the probable transmitter of the disease. The black rat (Rattus ratus) was found to be contributing to maintenance of the parasite life cycle. VL is primarily a disease of children, and 80% of cases were Saudi's, while cases from Yeminis nationality represent the majority of non- Saudi patients. The common clinical presentation consist of chronic fever, abdominal distention, weight loss, anemia and hepatosplenomegaly. Laboratory findings include: anemia, leukopenia, thrombocytopenia, hypoalbuminemia, hyperproteinaemia and hypergammaglobulinemia, low serum iron, and abnormal liver enzymes. Occurrence of jaundice has been identified as a bad prognostic sign. Diagnosis relying on direct smears from bone marrow aspirates was the commonest tool used, and also is advocated by the National Leishmaniasis Control Program (NLCP). Sodium stibogluconate (SSG) is the main drug used to treat VL cases, while Ambisome is preserved for complicated cases. Chemical control of sand flies using indoor residual spraying (IRS) with synthetic pyrethroids has been the most effective measure applied to prevent vector-human contact and disease transmission. The geographical overlap of VL and Malaria has facilitated the adoption and implementation of integrated vector control strategies. After reaching a zero case in 2019, the Ministry of Health (MoH) has a new commitment and facing a great challenge which are maintenance of current situation and elimination of VL. Through the support of stakeholders, encouragement of community participation, preparedness and readiness of leishmaniasis personnel, the new mission of the NLCP now is elimination of the scourge of VL from the country.
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13
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Arbeláez N, Moreno J, Murillo J, Montoya A, Robledo SM, Vélez A, Vélez ID. First Report of an Urban Case of Canine Visceral Leishmaniasis in the Municipality of Cali, Colombia. Am J Trop Med Hyg 2020; 102:289-293. [PMID: 31802736 DOI: 10.4269/ajtmh.19-0515] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
American visceral leishmaniasis (VL) is a vector-borne disease caused by Leishmania infantum (syn. chagasi) and transmitted by Lutzomyia longipalpis and Lutzomyia evansi phlebotomine sand flies. Dogs not only are the main host reservoirs of the parasite but also suffer the disease; therefore, canine VL (CVL) has assumed an important role in public health. In Colombia, human and CVL are restricted to two transmission foci: one in the north region (Caribbean coast) and other in the central south region (middle Magdalena River Valley). We present a CVL case involving a 2-year-old male dog with a history of lack of appetite, general weakness, and progressive loss of weight. A diagnosis of CVL was obtained using the direct parasitological examination in spleen and bone marrow samples stained with Giemsa and RT-qPCR. The infecting Leishmania species was identified as L. infantum by PCR-restriction fragment length polymorphism amplifying the Hsp70 gene from bone marrow and spleen samples and confirming by sequencing. The patient responded favorably to treatment with intramuscular meglumine antimoniate at a dose of 100 mg/kg daily for 8 weeks and oral allopurinol at a dose of 10 mg/kg every 12 hours until new indication. This is the first report of urban CVL in the city of Cali, Colombia, highlighting the need for surveillance and control programs in the municipalities of the department of Valle del Cauca, a region where VL has not been informed before. The findings also indicate the need to reinforce the surveillance programs in other rural and urban regions of the country where favorable eco-epidemiological conditions exist.
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Affiliation(s)
- Natalia Arbeláez
- PECET-Facultad de Medicina, Universidad de Antioquia, Medellín, Colombia
| | | | - Javier Murillo
- PECET-Facultad de Medicina, Universidad de Antioquia, Medellín, Colombia
| | - Andrés Montoya
- PECET-Facultad de Medicina, Universidad de Antioquia, Medellín, Colombia
| | - Sara M Robledo
- PECET-Facultad de Medicina, Universidad de Antioquia, Medellín, Colombia
| | - Andrés Vélez
- PECET-Facultad de Medicina, Universidad de Antioquia, Medellín, Colombia
| | - Iván D Vélez
- PECET-Facultad de Medicina, Universidad de Antioquia, Medellín, Colombia
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14
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Guegan H, Ory K, Belaz S, Jan A, Dion S, Legentil L, Manuel C, Lemiègre L, Vives T, Ferrières V, Gangneux JP, Robert-Gangneux F. In vitro and in vivo immunomodulatory properties of octyl-β-D-galactofuranoside during Leishmania donovani infection. Parasit Vectors 2019; 12:600. [PMID: 31870416 PMCID: PMC6929453 DOI: 10.1186/s13071-019-3858-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2019] [Accepted: 12/17/2019] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The chemotherapeutic arsenal available to treat visceral leishmaniasis is currently limited, in view of many drawbacks such as high cost, toxicity or emerging resistance. New therapeutic strategies are particularly needed to improve the management and the outcome in immunosuppressed patients. The combination of an immunomodulatory drug to a conventional anti-Leishmania treatment is an emerging concept to reverse the immune bias from Th2 to Th1 response to boost healing and prevent relapses. METHODS Here, immunostimulating and leishmanicidal properties of octyl-β-D-galactofuranose (Galf) were assessed in human monocyte-derived macrophages (HM) and in a murine model, after challenge with Leishmania donovani promastigotes. We recorded parasite loads and expression of various cytokines and immune effectors in HM and mouse organs (liver, spleen, bone marrow), following treatment with free (Galf) and liposomal (L-Galf) formulations. RESULTS Both treatments significantly reduced parasite proliferation in HM, as well as liver parasite burden in vivo (Galf, P < 0.05). Consistent with in vitro results, we showed that Galf- and L-Galf-treated mice displayed an enhanced Th1 immune response, particularly in the spleen where pro-inflammatory cytokines TNF-α, IL-1β and IL-12 were significantly overexpressed compared to control group. The hepatic recruitment of myeloid cells was also favored by L-Galf treatment as evidenced by the five-fold increase of myeloperoxidase (MPO) induction, which was associated with a higher number of MPO-positive cells within granulomas. By contrast, the systemic level of various cytokines such as IL-1β, IL-6, IL-17A or IL-27 was drastically reduced at the end of treatment. CONCLUSIONS Overall, these results suggest that Galf could be tested as an adjuvant in combination with current anti-parasitic drugs, to restore an efficient immune response against infection in a model of immunosuppressed mice.
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Affiliation(s)
- Hélène Guegan
- CHU Rennes, Inserm, EHESP IRSET (Institut de Recherche en Santé Environnement et Travail) - UMR_S 1085, University of Rennes, 35000, Rennes, France
| | - Kevin Ory
- Inserm, EHESP, IRSET (Institut de Recherche en Santé Environnement et Travail) - UMR_S 1085, University of Rennes, 35000, Rennes, France
| | - Sorya Belaz
- CHU Rennes, Inserm, EHESP IRSET (Institut de Recherche en Santé Environnement et Travail) - UMR_S 1085, University of Rennes, 35000, Rennes, France
| | - Aurélien Jan
- Inserm, EHESP, IRSET (Institut de Recherche en Santé Environnement et Travail) - UMR_S 1085, University of Rennes, 35000, Rennes, France
| | - Sarah Dion
- Inserm, EHESP, IRSET (Institut de Recherche en Santé Environnement et Travail) - UMR_S 1085, University of Rennes, 35000, Rennes, France
| | - Laurent Legentil
- Ecole Nationale Supérieure de Chimie, CNRS, UMR 6226, University of Rennes, avenue du Général Leclerc CS 50837, 35708, Rennes cedex 7, France
| | - Christelle Manuel
- Inserm, EHESP, IRSET (Institut de Recherche en Santé Environnement et Travail) - UMR_S 1085, University of Rennes, 35000, Rennes, France
| | - Loïc Lemiègre
- Ecole Nationale Supérieure de Chimie, CNRS, UMR 6226, University of Rennes, avenue du Général Leclerc CS 50837, 35708, Rennes cedex 7, France
| | - Thomas Vives
- Ecole Nationale Supérieure de Chimie, CNRS, UMR 6226, University of Rennes, avenue du Général Leclerc CS 50837, 35708, Rennes cedex 7, France
| | - Vincent Ferrières
- Ecole Nationale Supérieure de Chimie, CNRS, UMR 6226, University of Rennes, avenue du Général Leclerc CS 50837, 35708, Rennes cedex 7, France
| | - Jean-Pierre Gangneux
- CHU Rennes, Inserm, EHESP IRSET (Institut de Recherche en Santé Environnement et Travail) - UMR_S 1085, University of Rennes, 35000, Rennes, France
| | - Florence Robert-Gangneux
- CHU Rennes, Inserm, EHESP IRSET (Institut de Recherche en Santé Environnement et Travail) - UMR_S 1085, University of Rennes, 35000, Rennes, France.
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15
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Luz JGG, Carvalho AGD, Naves DB, Dias JVL, Fontes CJF. Where, when, and how the diagnosis of human visceral leishmaniasis is defined: answers from the Brazilian control program. Mem Inst Oswaldo Cruz 2019; 114:e190253. [PMID: 31664313 PMCID: PMC6821129 DOI: 10.1590/0074-02760190253] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2019] [Accepted: 10/08/2019] [Indexed: 11/21/2022] Open
Abstract
BACKGROUND Timely diagnosis is recommended by the Brazilian Visceral Leishmaniasis (VL) Surveillance and Control Program to reduce case fatality. Attempts at assessing this topic in Brazil are scarce. OBJECTIVE This study aimed to describe where, when, and how the diagnosis of VL has been performed in a Brazilian endemic setting. METHODS Data of all autochthonous cases confirmed between 2011 and 2016 (N = 81) were recorded. The care-seeking itinerary until the confirmation of VL diagnosis was assessed among 57 patients. FINDINGS The majority of VL cases (79.1%) were reported by referral hospitals. The patients mainly sought primary health care centres at the onset of symptoms. However, they had to visit seven health services on average to achieve a confirmed diagnosis. The time from the onset of symptoms to the diagnosis of VL (TD) ranged from 1-212 (median, 25) days. The TD was longer among adult patients. There was a direct correlation between the patient’s age and TD (r = 0.22; p = 0.047) and a higher occurrence of deaths due to the disease among older patients (p = 0.002). Almost all the patients (98.9%) underwent laboratory investigation, and the VL diagnosis was mainly confirmed based on clinical-laboratory criteria (92.6%). Positive results for the indirect fluorescence antibody test (22.7%) and parasitological examination plus rk39-based immunochromatographic tests (21.3%) were commonly employed. MAIN CONCLUSIONS VL diagnosis was predominantly conducted in hospitals with a long TD and wide application of serology. These findings may support measures focused on early diagnosis, including a greater involvement of the primary health care system.
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Affiliation(s)
- João Gabriel Guimarães Luz
- Universidade Federal de Mato Grosso, Instituto de Ciências Exatas e Naturais, Curso de Medicina, Rondonópolis, MT, Brasil.,Universidade Federal de Mato Grosso, Faculdade de Medicina, Programa de Pós-Graduação em Ciências da Saúde, Cuiabá, MT, Brasil
| | - Amanda Gabriela de Carvalho
- Universidade Federal de Mato Grosso, Instituto de Ciências Exatas e Naturais, Curso de Medicina, Rondonópolis, MT, Brasil.,Universidade Federal de Mato Grosso, Faculdade de Medicina, Programa de Pós-Graduação em Ciências da Saúde, Cuiabá, MT, Brasil
| | - Danilo Bueno Naves
- Universidade Federal de Mato Grosso, Instituto de Ciências Exatas e Naturais, Curso de Medicina, Rondonópolis, MT, Brasil
| | - João Victor Leite Dias
- Universidade Federal dos Vales do Jequitinhonha e Mucuri, Faculdade de Medicina, Teófilo Otoni, MG, Brasil
| | - Cor Jesus Fernandes Fontes
- Universidade Federal de Mato Grosso, Faculdade de Medicina, Programa de Pós-Graduação em Ciências da Saúde, Cuiabá, MT, Brasil.,Faculdade de Ciências Biomédicas de Cacoal, Curso de Medicina, Cacoal, RO, Brasil
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16
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de Carvalho CA, Ferrão TF, de Freitas FRN, de Andrade HF. High levels of serum glycans monovalent IgG immune complexes detected by dissociative ELISA in experimental visceral leishmaniasis. Immunology 2019; 158:314-321. [PMID: 31576564 DOI: 10.1111/imm.13118] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2019] [Revised: 08/05/2019] [Accepted: 09/05/2019] [Indexed: 02/02/2023] Open
Abstract
Visceral leishmaniasis (VL) is epidemic in Brazil with an increasing incidence of human cases and canine reservoirs, with host hypergammaglobulinemia. Conventional enzyme-linked immunosorbent assay (cELISA) based on several parasitic antigens is the main method for diagnosis and indication of treatment. Dissociative ELISA (dELISA) uses acidic treatment to free immunoglobulin G (IgG) from immune complexes, and its use revealed a significant positive fraction of suspected cases with negative serology. Looking for small molecules or haptens that block IgG antibodies, we purified by molecular exclusion chromatography, 1000-3000 MW molecules from promastigote soluble extract, mostly oligosaccharides comprising 6-13 sugar residues using MALDI-TOF analysis. Glycan-BSA complex (GBC) was constructed by conjugating promastigote glycans to BSA molecules, allowing their use in the solid support in cELISA or dELISA. Sera from experimentally infected hamsters showed higher levels of blocked monomeric IgG during infection, mostly against GBC, which was also present in lower concentrations in the promastigote soluble extract dELISA. Those data show that most of the specific monomeric IgG in serum are blocked by haptens composed by glycans produced by the parasite, better detected in the high dilution of sera in the dELISA assays. dELISA is a useful technique for detecting blocked monomeric antibodies that could have difficult clearance from blood, which could result in hypergammaglobulinemia.
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Affiliation(s)
| | - Thiago Fidelis Ferrão
- Laboratório de Protozoologia, Instituto de Medicina Tropical da Universidade de São Paulo, São Paulo, Brazil
| | | | - Heitor Franco de Andrade
- Laboratório de Protozoologia, Instituto de Medicina Tropical da Universidade de São Paulo, São Paulo, Brazil
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Lamattina D, Berrozpe PE, Casas N, Moya SL, Giuliani MG, Costa SA, Arrabal JP, Martínez MF, Rivero MR, Salas M, Humeres CA, Liotta DJ, Meichtry MB, Salomón OD. Twice upon a time: The progression of canine visceral leishmaniasis in an Argentinean city. PLoS One 2019; 14:e0219395. [PMID: 31276573 PMCID: PMC6611631 DOI: 10.1371/journal.pone.0219395] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Accepted: 06/21/2019] [Indexed: 11/18/2022] Open
Abstract
Canine Visceral Leishmaniasis (CVL) prevalence, spatial distribution and associated factors were assessed in four locations in Iguazú department in 2014 and in Puerto Iguazú city again in 2018. The city areas were divided into a grid of 400x400m cells. All cells were sampled in 2014 and a random subsampling was developed in 2018. In each cell, five dogs clustered in a 'critical scenario' (prone to have vectors) were sampled. A rapid immunochromatographic dipstick was used to detect antibodies against Leishmania infantum, confirming by lymph node smears observation and PCR. For Puerto Iguazú, Generalized Linear Models (GLMs) were constructed considering environmental, dog and clinical variables. Pearson's Chi square and Fisher's exact tests were employed to evaluate the association between CVL, dog clinical signs and infestation with other parasites. Cartographic outputs were made and Moran's I indices were calculated as spatial autocorrelation indicators. CVL prevalence rates were 26.18% in 2014 and 17.50% in 2018. No associations were established in environmental models, but dog age and repellent use were significant when running 2014 dog models. Clinical models showed significant associations between seropositive dogs and ophthalmological, dermal signs and onychogryphosis in 2014. In 2018, only adenomegaly was associated. The results of global Moran´s I were not significant but regarding local analysis, six sites in 2014 and one in 2018 presented autocorrelation with neighboring sites. The decrease in CVL prevalence may be associated to transmission stabilization, which could explain the lack of associations with dog-related variables. Further, spatial distribution of CVL is a poor evidence for design of transmission control measures but could be important in case of intensive parasite circulation or when the first autochthonous cases appear. For control success, sensitivity of diagnostic methods, political will and adequate material resources remain critical. Modeling of multiple variables will be required to identify factors that drive disease stabilization/destabilization.
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Affiliation(s)
- Daniela Lamattina
- Instituto Nacional de Medicina Tropical (INMeT), Ministerio de Salud y Desarrollo Social de la Nación, Puerto Iguazú, Misiones, Argentina
| | - Pablo Eduardo Berrozpe
- Instituto Nacional de Medicina Tropical (INMeT), Ministerio de Salud y Desarrollo Social de la Nación, Puerto Iguazú, Misiones, Argentina
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
| | - Natalia Casas
- Dirección Nacional de Epidemiología y Análisis de la Situación de Salud, Ministerio de Salud y Desarrollo Social de la Nación, Buenos Aires, Argentina
| | - Sofía Lorian Moya
- Instituto Nacional de Medicina Tropical (INMeT), Ministerio de Salud y Desarrollo Social de la Nación, Puerto Iguazú, Misiones, Argentina
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
| | - Magalí Gabriela Giuliani
- Instituto Nacional de Medicina Tropical (INMeT), Ministerio de Salud y Desarrollo Social de la Nación, Puerto Iguazú, Misiones, Argentina
| | - Sebastián Andrés Costa
- Instituto de Biología Subtropical, Facultad de Ciencias Forestales, Universidad Nacional de Misiones, Puerto Iguazú, Misiones, Argentina
| | - Juan Pablo Arrabal
- Instituto Nacional de Medicina Tropical (INMeT), Ministerio de Salud y Desarrollo Social de la Nación, Puerto Iguazú, Misiones, Argentina
| | - Mariela Florencia Martínez
- Instituto Nacional de Medicina Tropical (INMeT), Ministerio de Salud y Desarrollo Social de la Nación, Puerto Iguazú, Misiones, Argentina
| | - María Romina Rivero
- Instituto Nacional de Medicina Tropical (INMeT), Ministerio de Salud y Desarrollo Social de la Nación, Puerto Iguazú, Misiones, Argentina
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
| | - Martín Salas
- Instituto Nacional de Medicina Tropical (INMeT), Ministerio de Salud y Desarrollo Social de la Nación, Puerto Iguazú, Misiones, Argentina
| | - Cristian Alejandro Humeres
- Instituto Nacional de Medicina Tropical (INMeT), Ministerio de Salud y Desarrollo Social de la Nación, Puerto Iguazú, Misiones, Argentina
| | - Domingo Javier Liotta
- Instituto Nacional de Medicina Tropical (INMeT), Ministerio de Salud y Desarrollo Social de la Nación, Puerto Iguazú, Misiones, Argentina
| | - María Belén Meichtry
- Instituto Nacional de Medicina Tropical (INMeT), Ministerio de Salud y Desarrollo Social de la Nación, Puerto Iguazú, Misiones, Argentina
| | - Oscar Daniel Salomón
- Instituto Nacional de Medicina Tropical (INMeT), Ministerio de Salud y Desarrollo Social de la Nación, Puerto Iguazú, Misiones, Argentina
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
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18
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Nascimento LFMD, Moura LDD, Lima RT, Cruz MDSPE. Novos adjuvantes vacinais: importante ferramenta para imunoterapia da leishmaniose visceral. HU REVISTA 2019. [DOI: 10.34019/1982-8047.2018.v44.14123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Atualmente, muitas das vacinas em desenvolvimento são aquelas compostas de proteínas antigênicas individuais de parasitas ou uma combinação de vários antígenos individuais que são produzidos como produtos recombinantes obtidos por técnicas de biologia molecular. Dentre elas a Leish-111f e sua variação Leish-110f tem ganhado destaque na proteção contra a LV e LC e alcançaram estudos de fase II em seres humanos. A eficácia de uma vacina é otimizada pela adição de adjuvantes imunológicos. No entanto, embora os adjuvantes tenham sido usados por mais de um século, até o momento, apenas alguns adjuvantes são aprovados para o uso em humanos, a maioria destinada a melhorar a eficácia da vacina e a produção de anticorpos protetores específicos do antígeno. Os mecanismos de ação dos adjuvantes imunológicos são diversos, dependendo da sua natureza química e molecular sendo capazes de ativar células imunes especificas que conduzem a respostas imunes inatas e adaptativas melhoradas. Embora o mecanismo de ação molecular detalhado de muitos adjuvantes ainda seja desconhecido, a descoberta de receptores Toll-like (TLRs) forneceu informações críticas sobre o efeito imunoestimulador de numerosos componentes bacterianos que envolvem interação com receptores TLRs, mostrando que estes ligantes melhoram tanto a qualidade como a quantidade de respostas imunes adaptativas do hospedeiro quando utilizadas em formulações de vacinais direcionadas para doenças. O potencial desses adjuvantes de TLR em melhorar o design e os resultados de várias vacinas está em constante evolução, à medida que novos agonistas são descobertos e testados em modelos experimentais e estudos clínicos de vacinação. Nesta revisão, é apresentado um resumo do progresso recente no desenvolvimento de proteínas recombinantes de segunda geração e adjuvantes de TLR, sendo o foco principal nos TLR4 e suas melhorias.
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Carvalho AG, Luz JGG, Rodrigues LD, Dias JVL, Fontes CJF. Factors associated with Leishmania spp. infection in domestic dogs from an emerging area of high endemicity for visceral leishmaniasis in Central-Western Brazil. Res Vet Sci 2019; 125:205-211. [PMID: 31260840 DOI: 10.1016/j.rvsc.2019.06.013] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2018] [Revised: 06/19/2019] [Accepted: 06/19/2019] [Indexed: 11/19/2022]
Abstract
The factors associated with Leishmania spp. infection in dogs are still poorly understood. This study aimed to identify such factors among domestic dogs from the Brazilian municipality of Rondonópolis, which recently emerged as an endemic area with intense transmission of human visceral leishmaniasis (VL). It was a household-based cross-sectional study conducted between 2016 and 2017. Interviews were conducted with 405 dog owners considering their socioeconomic characteristics, and environmental aspects of the household and its adjacent areas. In addition, 600 dogs were evaluated regarding physical characteristics, behavior, and care provided by the owner. Seropositive animals were those that showed reactivity in a rapid immunochromatographic test and enzyme-linked immunosorbent assay, which are currently recommended for canine visceral leishmaniasis (CVL) diagnosis in Brazil. A multivariable logistic regression analysis was employed to determine the associated factors. Low social class [OR = 2.0; 95%CI = (1.2-3.2)], presence of acerola tree (Malpighia emarginata) in the yard [OR = 2.2; 95%CI = (1.2-4.1)], presence of more than one dog in the household [OR = 2.0; 95%CI = (1.3-3.3)], horse and/or cattle breeding [OR = 12.0; 95%CI = (1.9-73.6)], existence of houses with yard adjacent to the home [OR = 4.0; 95%CI = (1.3-12.2)], presence of apparent signs consistent with CVL [OR = 10.6; 95%CI = (5.8-19.4)], dog staying mostly in the yard during the day [(OR = 4.8; 95%CI = (1.1-21.4)], and lack of cleaning of the dog's shelter [(OR = 1.9; 95%CI = (1.1-3.2)] were identified as the factors associated with Leishmania spp. infection. These results support the importance of socioeconomic and environmental aspects in the occurrence of Leishmania spp. infection. In addition, they may be useful in guiding control strategies in areas where zoonotic VL is endemic.
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Affiliation(s)
- Amanda G Carvalho
- School of Medicine, Institute of Exact and Natural Sciences, Federal University of Mato Grosso, Rondonópolis, MT 78735-901, Brazil; School of Medicine, Post-Graduation Program in Health Sciences, Federal University of Mato Grosso, Cuiabá, MT 78060-900, Brazil.
| | - João Gabriel G Luz
- School of Medicine, Institute of Exact and Natural Sciences, Federal University of Mato Grosso, Rondonópolis, MT 78735-901, Brazil; School of Medicine, Post-Graduation Program in Health Sciences, Federal University of Mato Grosso, Cuiabá, MT 78060-900, Brazil
| | - Luane D Rodrigues
- School of Medicine, Institute of Exact and Natural Sciences, Federal University of Mato Grosso, Rondonópolis, MT 78735-901, Brazil
| | - João Victor L Dias
- School of Medicine, Federal University of Jequitinhonha and Mucuri Valleys, Téofilo Otoni, MG 39803-371, Brazil
| | - Cor Jesus F Fontes
- School of Medicine, Post-Graduation Program in Health Sciences, Federal University of Mato Grosso, Cuiabá, MT 78060-900, Brazil; Júlio Müller University Hospital, Federal University of Mato Grosso, Cuiabá, MT 78048-902, Brazil
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20
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Silva CJD, Mattos CB, Felipin KP, Silva HPDJ, Cantanhêde LM, Porrozzi R, Medeiros JF, Ferreira RDGM. First autochthonous case of canine visceral leishmaniasis in Rondônia, Brazil, a region with no history of visceral leishmaniasis. Rev Soc Bras Med Trop 2018; 51:712-715. [PMID: 30304285 DOI: 10.1590/0037-8682-0143-2017] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Accepted: 07/05/2018] [Indexed: 11/21/2022] Open
Abstract
This report describes the first autochthonous case of canine visceral leishmaniasis in Rondônia, northern Brazil. A canine resident of the municipality of Cacoal, with clinical signs and symptoms of visceral leishmaniasis, was treated by a veterinarian. Samples were analyzed by a reference laboratory. Dual-path platform (DPP) assay, indirect immunofluorescence technique (IIT), enzyme-linked immunosorbent assay (ELISA), polymerase chain reaction (PCR), isolation in a culture medium, and direct parasitological analysis were performed. DPP assay, IIT, and ELISA revealed positive results for Leishmania; PCR identified the species as Leishmania infantum. Based on the clinical presentation and test results, canine visceral leishmaniasis was diagnosed.
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Affiliation(s)
| | | | | | | | | | - Renato Porrozzi
- Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Rio de Janeiro, RJ, Brasil
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21
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Gomez SA, Chapman LAC, Dilger E, Courtenay O, Picado A. Estimating the efficacy of community-wide use of systemic insecticides in dogs to control zoonotic visceral leishmaniasis: A modelling study in a Brazilian scenario. PLoS Negl Trop Dis 2018; 12:e0006797. [PMID: 30222756 PMCID: PMC6160230 DOI: 10.1371/journal.pntd.0006797] [Citation(s) in RCA: 8] [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: 05/08/2018] [Revised: 09/27/2018] [Accepted: 08/28/2018] [Indexed: 12/31/2022] Open
Abstract
Systemic insecticides in dogs have been suggested as a public health intervention to prevent human cases of Zoonotic Visceral Leishmaniasis (ZVL). But, currently there are no systemic insecticides for dogs registered against zoo-anthropophilic pool blood feeding phlebotomine flies. We predict the impact of community-wide use of systemic insecticide in dog populations as a public health measure to control transmission of Leishmania infantum to humans using a mathematical model. We developed a Susceptible-Exposed-Infected (SEI) compartmental model to describe L. infantum transmission dynamics in dogs, with a vectorial capacity term to represent transmission between L. infantum-hosting dogs via phlebotomine flies. For Infected (I) dogs two levels of infectiousness were modelled, high infectiousness and low infectiousness. Human incidence was estimated through its relationship to infection in the dog population. We evaluated outcomes from a wide range of scenarios comprising different combinations of initial insecticide efficacy, duration of insecticide efficacy over time, and proportion of the dog population treated (60%, 70% & 80%). The same reduction in human infection incidence can be achieved via different combinations of insecticide efficacy, duration and dog coverage. For example, a systemic insecticide with an initial efficacy of 80% and 6 months above 65% efficacy would require treating at least 70% of the dogs to reduce the human infection incidence by 50%. Sensitivity analysis showed that the model outcome was most sensitive to baseline values of phlebotomine fly daily survival rate and insecticide coverage. Community-wide use of systemic insecticides applied to the “L. infantum canine reservoir” can significantly reduce human incidence of L. infantum infection. The results of this mathematical model can help defining the insecticide target product profile and how the insecticide should be applied to maximise effectiveness. Zoonotic visceral leishmaniasis (ZVL) is a potentially deadly disease in humans caused by Leishmania infantum. This leishmania species can be delivered by pool blood feeding zoo-anthropophilic phlebotomine flies to several mammals, the dog population being recognized as the main reservoir. Transmission from infected dogs to humans is through the bite of female phlebotomine sand flies. The disease is endemic in several countries and Brazil has a high prevalence of cases with over 3000 ZVL cases reported per year. The main, inefficient and highly controversial, control measure in Brazil has been culling sero-positive dogs. The community-wide use of systemic insecticides in dogs could be an alternative to control L. infantum transmission from phlebotomine flies to humans. The rationale is that phlebotomine flies which sampled their blood meals from dogs treated with systemic insecticides would die reducing the risk of L. infantum transmission. To reduce the number of ZVL cases, a large proportion of dogs in the community should be treated and the systemic insecticide used should be effective in killing phlebotomine flies acting as vectors of L. infantum parasites for a significant amount of time. We used a mathematical model mimicking L. infantum transmission to show that this novel vector control strategy could be effective. We identified the combination of different key parameters (e.g. insecticide efficacy, duration and proportion of dogs treated) that could lead to a significant reduction of the risk of L. infantum infection in humans.
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Affiliation(s)
- Sonia A. Gomez
- ISGlobal-Hospital Clínic, Universitat de Barcelona, Barcelona, Spain
- * E-mail: (AP); (SAG)
| | - Lloyd A. C. Chapman
- Department of Global Health and Development, London School of Hygiene and Tropical Medicine, London, United Kingdom
- School of Life Sciences, University of Warwick, Gibbet Hill Campus, Coventry, United Kingdom
| | - Erin Dilger
- School of Life Sciences, University of Warwick, Gibbet Hill Campus, Coventry, United Kingdom
| | - Orin Courtenay
- School of Life Sciences, University of Warwick, Gibbet Hill Campus, Coventry, United Kingdom
| | - Albert Picado
- ISGlobal-Hospital Clínic, Universitat de Barcelona, Barcelona, Spain
- * E-mail: (AP); (SAG)
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