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Pabon-Rodriguez FM, Brown GD, Scorza BM, Petersen CA. Within-host bayesian joint modeling of longitudinal and time-to-event data of Leishmania infection. PLoS One 2024; 19:e0297175. [PMID: 38335163 PMCID: PMC10857584 DOI: 10.1371/journal.pone.0297175] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2023] [Accepted: 12/30/2023] [Indexed: 02/12/2024] Open
Abstract
The host immune system plays a significant role in managing and clearing pathogen material during an infection, but this complex process presents numerous challenges from a modeling perspective. There are many mathematical and statistical models for these kinds of processes that take into account a wide range of events that happen within the host. In this work, we present a Bayesian joint model of longitudinal and time-to-event data of Leishmania infection that considers the interplay between key drivers of the disease process: pathogen load, antibody level, and disease. The longitudinal model also considers approximate inflammatory and regulatory immune factors. In addition to measuring antibody levels produced by the immune system, we adapt data from CD4+ and CD8+ T cell proliferation, and expression of interleukin 10, interferon-gamma, and programmed cell death 1 as inflammatory or regulatory factors mediating the disease process. The model is developed using data collected from a cohort of dogs naturally exposed to Leishmania infantum. The cohort was chosen to start with healthy infected animals, and this is the majority of the data. The model also characterizes the relationship features of the longitudinal outcomes and time-to-death due to progressive Leishmania infection. In addition to describing the mechanisms causing disease progression and impacting the risk of death, we also present the model's ability to predict individual trajectories of Canine Leishmaniosis (CanL) progression. The within-host model structure we present here provides a way forward to address vital research questions regarding the understanding of the progression of complex chronic diseases such as Visceral Leishmaniasis, a parasitic disease causing significant morbidity worldwide.
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Affiliation(s)
- Felix M. Pabon-Rodriguez
- Department of Biostatistics, The University of Iowa College of Public Health, Iowa City, Iowa, United States of America
| | - Grant D. Brown
- Department of Biostatistics, The University of Iowa College of Public Health, Iowa City, Iowa, United States of America
| | - Breanna M. Scorza
- Department of Epidemiology, The University of Iowa College of Public Health, Iowa City, Iowa, United States of America
- Center for Emerging Infectious Diseases, The University of Iowa College of Public Health, Iowa City, Iowa, United States of America
| | - Christine A. Petersen
- Department of Epidemiology, The University of Iowa College of Public Health, Iowa City, Iowa, United States of America
- Center for Emerging Infectious Diseases, The University of Iowa College of Public Health, Iowa City, Iowa, United States of America
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Pabon-Rodriguez FM, Brown GD, Scorza BM, Petersen CA. Within-Host Bayesian Joint Modeling of Longitudinal and Time-to-Event Data of Leishmania Infection. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.11.557114. [PMID: 37745423 PMCID: PMC10515798 DOI: 10.1101/2023.09.11.557114] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/26/2023]
Abstract
The host immune system plays a significant role in managing and clearing pathogen material during an infection, but this complex process presents numerous challenges from a modeling perspective. There are many mathematical and statistical models for these kinds of processes that take into account a wide range of events that happen within the host. In this work, we present a Bayesian joint model of longitudinal and time-to-event data of Leishmania infection that considers the interplay between key drivers of the disease process: pathogen load, antibody level, and disease. The longitudinal model also considers approximate inflammatory and regulatory immune factors. In addition to measuring antibody levels produced by the immune system, we adapt data from CD4+ and CD8+ T cell proliferation, and expression of interleukin 10, interferon-gamma, and programmed cell death 1 as inflammatory or regulatory factors mediating the disease process. The model is developed using data collected from a cohort of dogs naturally exposed to Leishmania infantum. The cohort was chosen to start with healthy infected animals, and this is the majority of the data. The model also characterizes the relationship features of the longitudinal outcomes and time of death due to progressive Leishmania infection. In addition to describing the mechanisms causing disease progression and impacting the risk of death, we also present the model's ability to predict individual trajectories of Canine Leishmaniosis (CanL) progression. The within-host model structure we present here provides a way forward to address vital research questions regarding the understanding progression of complex chronic diseases such as Visceral Leishmaniasis, a parasitic disease causing significant morbidity worldwide.
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Affiliation(s)
- Felix M. Pabon-Rodriguez
- Department of Biostatistics, The University of Iowa College of Public Health, Iowa City, Iowa, United States
| | - Grant D. Brown
- Department of Biostatistics, The University of Iowa College of Public Health, Iowa City, Iowa, United States
| | - Breanna M. Scorza
- Department of Epidemiology, The University of Iowa College of Public Health, Iowa City, Iowa, United States
- Center for Emerging Infectious Diseases, The University of Iowa College of Public Health, Iowa City, Iowa, United States
| | - Christine A. Petersen
- Department of Epidemiology, The University of Iowa College of Public Health, Iowa City, Iowa, United States
- Center for Emerging Infectious Diseases, The University of Iowa College of Public Health, Iowa City, Iowa, United States
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Franssen SU, Sanders MJ, Berriman M, Petersen CA, Cotton JA. Geographic Origin and Vertical Transmission of Leishmania infantum Parasites in Hunting Hounds, United States. Emerg Infect Dis 2022; 28:1211-1223. [PMID: 35608628 PMCID: PMC9155895 DOI: 10.3201/eid2806.211746] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Vertical transmission of leishmaniasis is common but is difficult to study against the background of pervasive vector transmission. We present genomic data from dogs in the United States infected with Leishmania infantum parasites; these infections have persisted in the apparent absence of vector transmission. We demonstrate that these parasites were introduced from the Old World separately and more recently than L. infantum from South America. The parasite population shows unusual genetics consistent with a lack of meiosis: a high level of heterozygous sites shared across all isolates and no decrease in linkage with genomic distance between variants. Our data confirm that this parasite population has been evolving with little or no sexual reproduction. This demonstration of vertical transmission has profound implications for the population genetics of Leishmania parasites. When investigating transmission in complex natural settings, considering vertical transmission alongside vector transmission is vital.
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Barbosa de Castro R, Badaró de Moraes JV, Costa Bressan G, de Souza Vasconcellos R, Silva-Júnior A, Lopes Rangel Fietto J. Antigens and their diagnostic performance for Canine Visceral Leishmaniasis: A critical review. Vet Parasitol 2021; 301:109638. [PMID: 34920304 DOI: 10.1016/j.vetpar.2021.109638] [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: 09/16/2021] [Revised: 11/22/2021] [Accepted: 12/09/2021] [Indexed: 01/27/2023]
Abstract
Canine visceral leishmaniasis (CVL) is the most aggressive and lethal form of leishmaniasis manifesting in dogs and represents a major public health concern. Although there are sufficiently sensitive molecular tools for CVL diagnosis, they are not accessible at the main points of disease dissemination, in which context serodiagnosis has been used as an alternative tool on the epidemiological control. As an attempt to develop more accurate immunodiagnostic assays, many antigens have been tested over the years, on different platforms. This review aimed to access studies reporting new antigens that can be applied for CVL serodiagnosis. Articles published from January of 2016 to March of 2021 were retrieved from Google Scholar, Science Direct, and PubMed, using "Canine Visceral Leishmaniasis" and "Serodiagnosis" as keywords. In total, 1527 articles were identified, of which 42 were selected based on exclusion factors. Sensitivity, specificity, sample size, and sample quality data were extracted by manual curation and analyzed. Of the selected articles, 26 contemplated ELISA, which enabled a more thorough comparison and a critical review of these studies. Soluble Leishmania Antigens (SLA) and the A2 protein were used as controls in 53.8 and 46.15 % of these articles, respectively, and were evaluated separately; their frequent use was questioned. Subsequently, articles that evaluated other assay platforms, such as immunochromatography, immunosensors, and others, were also reported and evaluated. Finally, data relative to validation studies of commercial kits were briefly discussed. Our results show that there are several antigens with great potential for the development of accurate diagnostic tools, but further testing is required. The critical analysis also brings insights that can be useful for more assertive diagnostic development of more robust tools for CVL serodiagnosis.
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Affiliation(s)
- Raissa Barbosa de Castro
- Departamento de Bioquímica e Biologia Molecular, Universidade Federal de Viçosa, Av. P. H. Rolfs, s/n, Campus Universitário, CEP: 36570-000 Viçosa, MG, Brazil
| | - João Victor Badaró de Moraes
- Departamento de Biologia Geral, Av. P. H. Rolfs, s/n, Campus Universitário, CEP: 36570-000, Universidade Federal de Viçosa, Viçosa, MG, Brazil
| | - Gustavo Costa Bressan
- Departamento de Bioquímica e Biologia Molecular, Universidade Federal de Viçosa, Av. P. H. Rolfs, s/n, Campus Universitário, CEP: 36570-000 Viçosa, MG, Brazil
| | - Raphael de Souza Vasconcellos
- Departamento de Bioquímica e Biologia Molecular, Universidade Federal de Viçosa, Av. P. H. Rolfs, s/n, Campus Universitário, CEP: 36570-000 Viçosa, MG, Brazil
| | - Abelardo Silva-Júnior
- Departamento de Veterinária, Av. P. H. Rolfs, s/n, Campus Universitário, CEP: 36570-000, Universidade Federal de Viçosa, Viçosa, MG, Brazil
| | - Juliana Lopes Rangel Fietto
- Departamento de Bioquímica e Biologia Molecular, Universidade Federal de Viçosa, Av. P. H. Rolfs, s/n, Campus Universitário, CEP: 36570-000 Viçosa, MG, Brazil.
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Scorza BM, Mahachi KG, Cox AC, Toepp AJ, Leal-Lima A, Kumar Kushwaha A, Kelly P, Meneses C, Wilson G, Gibson-Corley KN, Bartholomay L, Kamhawi S, Petersen CA. Leishmania infantum xenodiagnosis from vertically infected dogs reveals significant skin tropism. PLoS Negl Trop Dis 2021; 15:e0009366. [PMID: 34613967 PMCID: PMC8523039 DOI: 10.1371/journal.pntd.0009366] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Revised: 10/18/2021] [Accepted: 09/24/2021] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Dogs are the primary reservoir for human visceral leishmaniasis due to Leishmania infantum. Phlebotomine sand flies maintain zoonotic transmission of parasites between dogs and humans. A subset of dogs is infected transplacentally during gestation, but at what stage of the clinical spectrum vertically infected dogs contribute to the infected sand fly pool is unknown. METHODOLOGY/PRINCIPAL FINDINGS We examined infectiousness of dogs vertically infected with L. infantum from multiple clinical states to the vector Lutzomyia longipalpis using xenodiagnosis and found that vertically infected dogs were infectious to sand flies at differing rates. Dogs with mild to moderate disease showed significantly higher transmission to the vector than dogs with subclinical or severe disease. We documented a substantial parasite burden in the skin of vertically infected dogs by RT-qPCR, despite these dogs not having received intradermal parasites via sand flies. There was a highly significant correlation between skin parasite burden at the feeding site and sand fly parasite uptake. This suggests dogs with high skin parasite burden contribute the most to the infected sand fly pool. Although skin parasite load and parasitemia correlated with one another, the average parasite number detected in skin was significantly higher compared to blood in matched subjects. Thus, dermal resident parasites were infectious to sand flies from dogs without detectable parasitemia. CONCLUSIONS/SIGNIFICANCE Together, our data implicate skin parasite burden and earlier clinical status as stronger indicators of outward transmission potential than blood parasite burden. Our studies of a population of dogs without vector transmission highlights the need to consider canine vertical transmission in surveillance and prevention strategies.
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Affiliation(s)
- Breanna M. Scorza
- Department of Epidemiology, University of Iowa, Iowa City, Iowa, United States of America
| | - Kurayi G. Mahachi
- Department of Epidemiology, University of Iowa, Iowa City, Iowa, United States of America
| | - Arin C. Cox
- Department of Epidemiology, University of Iowa, Iowa City, Iowa, United States of America
| | - Angela J. Toepp
- Department of Epidemiology, University of Iowa, Iowa City, Iowa, United States of America
| | - Adam Leal-Lima
- Department of Epidemiology, University of Iowa, Iowa City, Iowa, United States of America
| | | | - Patrick Kelly
- Department of Microbiology, University of Iowa, Iowa City, Iowa, United States of America
| | - Claudio Meneses
- National Institute of Allergy and Infectious Disease, NIH, Rockville, Maryland, United States of America
| | - Geneva Wilson
- Department of Epidemiology, University of Iowa, Iowa City, Iowa, United States of America
| | | | - Lyric Bartholomay
- Department of Epidemiology, University of Wisconsin, Madison, Wisconsin, United States of America
| | - Shaden Kamhawi
- National Institute of Allergy and Infectious Disease, NIH, Rockville, Maryland, United States of America
| | - Christine A. Petersen
- Department of Epidemiology, University of Iowa, Iowa City, Iowa, United States of America
- * E-mail:
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Meyers AC, Auckland L, Meyers HF, Rodriguez CA, Kontowicz E, Petersen CA, Travi BL, Sanders JP, Hamer SA. Epidemiology of Vector-Borne Pathogens Among U.S. Government Working Dogs. Vector Borne Zoonotic Dis 2021; 21:358-368. [PMID: 33601954 PMCID: PMC8086402 DOI: 10.1089/vbz.2020.2725] [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] [Indexed: 01/17/2023] Open
Abstract
Surveillance of U.S. domestic dogs for exposure to vector-borne pathogens can identify regions of transmission that are relevant for human and animal health. Working dogs with high levels of outdoor exposure may be sensitive indicators of local risk, owing to increased contact with vectors. We randomly selected 476 high-value government working dogs from 40 states to determine the prevalence of infection with Dirofilaria immitis and Rickettsia spp., and exposure to Ehrlichia spp., Anaplasma spp., and Borrelia burgdorferi, and identify risk factors for positivity. Additionally, we tested 100 of these dogs from Texas for Leishmania spp. where sand fly vectors occur. Previously published Trypanosoma cruzi infection data on these dogs were used to identify coinfection or co-exposures. Infection prevalence was 0.84% for D. immitis, and all dogs were negative for Rickettsia spp. DNA. Seroprevalence of each pathogen was: B. burgdorferi 0.84%, Ehrlichia spp. 1.3%, Anaplasma spp. 1.5%, Leishmania spp. 2.0%, and T. cruzi 12.2%. Coinfection or co-exposure took place in four (0.84%) dogs. In bivariable analysis, we found that D. immitis-positive and Ehrlichia-seropositive dogs were significantly older than negative dogs (p < 0.05). Furthermore, seroprevalence of Anaplasma spp. was significantly higher among dogs in the Northeast United States relative to other areas of the country (4.7% vs. ≤1.4%; p = 0.041). Although autochthonous Leishmania infections have been described in the United States, the cases reported herein may represent imported Leishmania infection. Most federal working dogs are bred in Europe, where the parasite is endemic and congenitally transmitted. Serological cross-reaction between T. cruzi and Leishmania spp. complicates diagnosis. In this study, the use of multiple testing strategies in a comparative complementary manner provided evidence for these dogs' true exposures. Comprehensive surveillance for vector-borne pathogens in dogs can improve clinician awareness and target prevention and treatment in a One Health manner.
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Affiliation(s)
- Alyssa C. Meyers
- Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, Texas, USA
| | - Lisa Auckland
- Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, Texas, USA
| | - Hannah F. Meyers
- Department of Chemistry, Kalamazoo College, Kalamazoo, Michigan, USA
| | - Carlos A. Rodriguez
- Texas A&M Veterinary Medical Diagnostic Laboratory, College Station, Texas, USA
| | - Eric Kontowicz
- Department of Epidemiology, College of Public Health, University of Iowa, Iowa City, Iowa, USA
| | - Christine A. Petersen
- Department of Epidemiology, College of Public Health, University of Iowa, Iowa City, Iowa, USA
| | - Bruno L. Travi
- Department of Internal Medicine (Infectious Diseases) and Microbiology and Immunology, University of Texas Medical Branch, Galveston, Texas, USA
| | - John P. Sanders
- Office of Workforce Health and Safety, Department of Homeland Security, Office of the Chief Human Capital Officer, Washington, District of Columbia, USA
| | - Sarah A. Hamer
- Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, Texas, USA.,Address correspondence to: Sarah A. Hamer, Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, 4458 TAMU, College Station, TX 77843-4458, USA
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Ozanne MV, Brown GD, Toepp AJ, Scorza BM, Oleson JJ, Wilson ME, Petersen CA. Bayesian compartmental models and associated reproductive numbers for an infection with multiple transmission modes. Biometrics 2020; 76:711-721. [PMID: 31785149 PMCID: PMC7673222 DOI: 10.1111/biom.13192] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2019] [Revised: 11/08/2019] [Accepted: 11/14/2019] [Indexed: 01/01/2023]
Abstract
Zoonotic visceral leishmaniasis (ZVL) is a serious neglected tropical disease that is endemic in 98 countries. ZVL is primarily transmitted via a sand fly vector. In the United States, it is enzootic in some canine populations; it is transmitted from infectious mother to pup transplacentally, and vector-borne transmission is absent. This absence affords a unique opportunity to study (1) vertical transmission dynamics in dogs and (2) the importance of vertical transmission in maintaining an infectious reservoir in the presence of a vector. In this paper, we present Bayesian compartmental models and reproductive number formulations to examine (1) and (2), providing a mechanism to plan and evaluate interventions in regions where both transmission modes are present. First, we propose an individual-level susceptible, infectious, removed (SIR) model to study the effect of maternal infection status during pregnancy on pup infection progression. We provide evidence that pups born to diagnostically positive mothers during pregnancy are more likely to become diagnostically positive both earlier in life, and at some point during their lifetime, than those born to diagnostically negative mothers. Second, we propose a population-level SIR model to study the impact of a vertically maintained reservoir on propagating infection in a naive canine population through emergent vector transmission using simulation studies. We also present reproductive numbers to quantify contributions of vertically infected and vector-infected dogs to maintaining infection in the population. We show that a vertically maintained canine reservoir can propagate infection in a theoretical naive population in the presence of a vector.
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Affiliation(s)
- Marie V Ozanne
- Department of Mathematics & Statistics, Mount Holyoke College, South Hadley, Massachusetts
- Department of Biostatistics, University of Iowa College of Public Health, Iowa City, Iowa
| | - Grant D Brown
- Department of Biostatistics, University of Iowa College of Public Health, Iowa City, Iowa
| | - Angela J Toepp
- Department of Epidemiology, University of Iowa College of Public Health, Iowa City, Iowa
| | - Breanna M Scorza
- Department of Epidemiology, University of Iowa College of Public Health, Iowa City, Iowa
| | - Jacob J Oleson
- Department of Biostatistics, University of Iowa College of Public Health, Iowa City, Iowa
| | - Mary E Wilson
- Department of Internal Medicine, University of Iowa Roy J and Lucille A Carver College of Medicine, Iowa City, Iowa
- Department of Microbiology, University of Iowa Roy J and Lucille A Carver College of Medicine, Iowa City, Iowa
- Iowa City VA Medical Center, Iowa City, Iowa
| | - Christine A Petersen
- Department of Epidemiology, University of Iowa College of Public Health, Iowa City, Iowa
- Center for Emerging Infectious Diseases, University of Iowa College of Public Health, Iowa City, Iowa
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Herrera G, Castillo A, Ayala MS, Flórez C, Cantillo-Barraza O, Ramirez JD. Evaluation of four rapid diagnostic tests for canine and human visceral Leishmaniasis in Colombia. BMC Infect Dis 2019; 19:747. [PMID: 31455227 PMCID: PMC6712844 DOI: 10.1186/s12879-019-4353-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2019] [Accepted: 08/02/2019] [Indexed: 11/30/2022] Open
Abstract
BACKGROUND Leishmaniasis caused by different species of Leishmania affect 98 countries worldwide. Visceral Leishmaniasis (VL) is the mortal clinical presentation of the disease that causes the dead to more than 90% of the patients who suffer it. The diagnosis of VL is made by the direct observation of the parasite in bone marrow, spleen and/or liver aspirates that requires complex proceedings. Therefore, serum samples are submitted to Indirect Immunofluorescence to identify the presence of anti-Leishmania antibodies. Despite the variability in the diagnostic performance of the Immunochromatographic Tests (ICTs), there are many evidences that suggest that ICTs can be used for epidemiological screening. However, in Colombia there are not any evidence about the performance of the ICTs for VL diagnosis, both for human and canine serum samples. Therefore, this study evaluated the diagnostic performance of 4 ICTs for VL (2 ICTs in human sera and 2 ICTs in canine sera) in samples from endemic areas of Colombia. METHODS We selected a total of 156 human serum samples (82 positive and 74 negative for VL) and 126 canine serum samples (71 positive and 54 negative) diagnosed by in house Indirect Immunofluorescence (IIF). The samples were submitted to the ICTs following the manufacturers' instructions. Statistical analysis was performed to evaluate the diagnostic performance of each ICT in comparison with the IIF. PCR for HSP70 gene and sanger sequencing was performed in samples with negative results for both ICTs. RESULTS The sensitivity (S) of both ICTs for human samples (Ad-bio Leishmania IgG/IgM Combo Rapid Test and Kalazar Detect™) was 91.5% and specificity (E) were 93.2 and 89.2% respectively, while for the ICTs tested on canine samples (Kalazar Detect™ Rapid Test, Canine and DPP® CVL rapid test) we found S values between 82.9 and 85.7% and E values between 79.6 and 92.6%. We found L. infantum by PCR and sequencing in 2 human samples, and L. braziliensis and L. amazonensis in canine serum samples that were negative by both ICTs. CONCLUSIONS We conclude that both tests evaluated on human samples have a similar diagnostic performance, while the Kalazar Detect™ Rapid Test, Canine showed a better diagnostic performance than the DPP® CVL rapid test evaluated on canine samples. Also, we suggest that it is necessary to design tests with antigens of the circulating strains to increase its diagnostic utility.
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Affiliation(s)
- Giovanny Herrera
- Grupo de Investigaciones Microbiológicas-UR (GIMUR), Departamento de Biología, Facultad de Ciencias Naturales y Matemáticas, Universidad del Rosario, Bogotá, Colombia
| | - Adriana Castillo
- Grupo de Parasitología, Instituto Nacional de Salud, Bogotá, Colombia
| | - Martha S. Ayala
- Grupo de Parasitología, Instituto Nacional de Salud, Bogotá, Colombia
| | - Carolina Flórez
- Grupo de Parasitología, Instituto Nacional de Salud, Bogotá, Colombia
| | - Omar Cantillo-Barraza
- Grupo Biología y Control de Enfermedades Infecciosas (BCEI), Sede de Investigación Universitaria, Universidad de Antioquia, Medellín, Colombia
| | - Juan David Ramirez
- Grupo de Investigaciones Microbiológicas-UR (GIMUR), Departamento de Biología, Facultad de Ciencias Naturales y Matemáticas, Universidad del Rosario, Bogotá, Colombia
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Toepp AJ, Bennett C, Scott B, Senesac R, Oleson JJ, Petersen CA. Maternal Leishmania infantum infection status has significant impact on leishmaniasis in offspring. PLoS Negl Trop Dis 2019; 13:e0007058. [PMID: 30759078 PMCID: PMC6391032 DOI: 10.1371/journal.pntd.0007058] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Revised: 02/26/2019] [Accepted: 12/05/2018] [Indexed: 01/21/2023] Open
Abstract
Visceral Leishmaniasis is a deadly disease caused by Leishmania infantum, endemic in more than 98 countries across the globe. Although the most common means of transmission is via a sand fly vector, there is growing evidence that vertical transmission may be critical for maintaining L. infantum infection within the reservoir, canine, population. Vertical transmission is also an important cause of infant morbidity and mortality particularly in sub-Saharan Africa. While vertical transmission of visceralizing species of Leishmania has been reported around the globe, risk factors associated with this unique means of Leishmania transmission have not been identified therefore interventions regarding this means of transmission have been virtually non-existent. Furthermore, the basic reproductive number, (R0), or number of new L. infantum infections that one infected mother or dam can cause has not been established for vertical transmission, also hampering the ability to assess the impact of this means of transmission within reservoir of human hosts. Canine Leishmaniosis (CanL) is enzootic within a U.S. hunting dog population. CanL is transmitted within this population via transplacental transmission with no reported vector transmission, despite many repeated attempts to find infected sand flies associated with these dogs and kennels. This population with predominantly, if not solely, vertical transmission of L. infantum was used to evaluate the critical risk factors for vertical transmission of Leishmania and establish the R0 of vertical L. infantum infection. Evaluation of 124 animals born to eighteen dams diagnostically positive for infection with L. infantum showed that there was a 13.84x greater chance of being positive for L. infantum within their lifetime if the mother was also positive within her lifetime (RR: 13.84, 95% CI: 3.54-54.20, p-value: <0.0001). The basic reproductive number for vertically transmitted L. infantum within this cohort was 4.12. These results underscore that there is a high risk of L. infantum infection to transmit from mother to offspring. Targeted public health interventions and control efforts that address vertical transmission of L. infantum are necessary in endemic countries to eliminate visceral leishmaniasis.
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Affiliation(s)
- Angela J. Toepp
- Department of Epidemiology, College of Public Health, University of Iowa, Iowa City, Iowa, United States of America
- Center for Emerging Infectious Diseases, University of Iowa Research Park, Coralville, Iowa, United States of America
| | - Carolyne Bennett
- Department of Epidemiology, College of Public Health, University of Iowa, Iowa City, Iowa, United States of America
- Center for Emerging Infectious Diseases, University of Iowa Research Park, Coralville, Iowa, United States of America
| | - Benjamin Scott
- Department of Epidemiology, College of Public Health, University of Iowa, Iowa City, Iowa, United States of America
- Center for Emerging Infectious Diseases, University of Iowa Research Park, Coralville, Iowa, United States of America
| | - Reid Senesac
- Department of Epidemiology, College of Public Health, University of Iowa, Iowa City, Iowa, United States of America
- Center for Emerging Infectious Diseases, University of Iowa Research Park, Coralville, Iowa, United States of America
| | - Jacob J. Oleson
- Department of Biostatistics, College of Public Health, University of Iowa, Iowa City, Iowa, United States of America
| | - Christine A. Petersen
- Department of Epidemiology, College of Public Health, University of Iowa, Iowa City, Iowa, United States of America
- Center for Emerging Infectious Diseases, University of Iowa Research Park, Coralville, Iowa, United States of America
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10
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Teixeira AIP, Silva DM, Vital T, Nitz N, de Carvalho BC, Hecht M, Oliveira D, Oliveira E, Rabello A, Romero GAS. Improving the reference standard for the diagnosis of canine visceral leishmaniasis: a challenge for current and future tests. Mem Inst Oswaldo Cruz 2019; 114:e180452. [PMID: 30726343 PMCID: PMC6358009 DOI: 10.1590/0074-02760180452] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2018] [Accepted: 01/04/2019] [Indexed: 11/25/2022] Open
Abstract
BACKGROUND Studies aimed at validating canine visceral leishmaniasis diagnostic tests present heterogeneous results regarding test accuracy, partly due to divergences in reference standards used and different infection evolution periods in animals. OBJECTIVE This study aimed to evaluate the accuracy of the rapid test-dual path platform (TR-DPP) (Biomanguinhos®), EIE-Leishmaniose-Visceral-Canina-Biomanguinhos (EIE-LVC) (Biomanguinhos®), enzyme-linked immunosorbent assay (ELISA) rK39 (in-house), and the direct agglutination test (DAT-Canis) against a reference standard comprising parasitological and molecular techniques. METHODS A phase II/III validation study was carried out in sample sera from 123 predominantly asymptomatic dogs living in an area endemic for visceral leishmaniasis. FINDINGS Sixty-nine (56.1%) animals were considered infected according to the reference standard. For each test, the sensitivity and specificity, respectively, were as follows: TR-DPP, 21.74% [confidence interval (CI)95% 13.64% to 32.82%] and 92.59% (CI95% 82.45% to 97.08%); EIE-LVC, 11.59% (CI95% 5.9% to 21.25%) and 90.74% (CI95% 80.09% to 95.98%); ELISA rK39, 37.68% (CI95% 27.18% to 49.48%) and 83.33% (CI95% 71.26% to 90.98%); and DAT-Canis, 18.84% (CI95% 11.35% to 29.61%) and 96.30% (CI95% 87.46% to 98.98%). CONCLUSION We concluded that improving the sensitivity of serum testing for diagnosing asymptomatic dogs must constitute a priority in the process of developing new diagnostic tests to be used in the visceral leishmaniasis control program in Brazil.
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Affiliation(s)
| | | | - Tamires Vital
- Universidade de Brasília, Núcleo de Medicina Tropical, Brasília, DF, Brasil
- Universidade de Brasília, Faculdade de Medicina, Laboratório Interdisciplinar de Biociências, Brasília, DF, Brasil
| | - Nadjar Nitz
- Universidade de Brasília, Faculdade de Medicina, Laboratório Interdisciplinar de Biociências, Brasília, DF, Brasil
| | | | - Mariana Hecht
- Universidade de Brasília, Faculdade de Medicina, Laboratório Interdisciplinar de Biociências, Brasília, DF, Brasil
| | - Diana Oliveira
- Grupo de Pesquisas Clínicas e Políticas Públicas em Doenças Infecciosas e Parasitárias, Belo Horizonte, MG, Brasil
| | - Edward Oliveira
- Grupo de Pesquisas Clínicas e Políticas Públicas em Doenças Infecciosas e Parasitárias, Belo Horizonte, MG, Brasil
| | - Ana Rabello
- Grupo de Pesquisas Clínicas e Políticas Públicas em Doenças Infecciosas e Parasitárias, Belo Horizonte, MG, Brasil
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11
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Toepp AJ, Monteiro GRG, Coutinho JFV, Lima AL, Larson M, Wilson G, Grinnage-Pulley T, Bennett C, Mahachi K, Anderson B, Ozanne MV, Anderson M, Fowler H, Parrish M, Willardson K, Saucier J, Tyrell P, Palmer Z, Buch J, Chandrashekar R, Brown GD, Oleson JJ, Jeronimo SMB, Petersen CA. Comorbid infections induce progression of visceral leishmaniasis. Parasit Vectors 2019; 12:54. [PMID: 30674329 PMCID: PMC6345068 DOI: 10.1186/s13071-019-3312-3] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Accepted: 01/13/2019] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND Visceral leishmaniasis (VL) is a vector borne zoonotic disease endemic in humans and dogs in Brazil. Due to the increased risk of human infection secondary to the presence of infected dogs, public health measures in Brazil mandate testing and culling of infected dogs. Despite this important relationship between human and canine infection, little is known about what makes the dog reservoir progress to clinical illness, significantly tied to infectiousness to sand flies. Dogs in endemic areas of Brazil are exposed to many tick-borne pathogens, which are likely to alter the immune environment and thus control of L. infantum. RESULTS A cross-sectional study of 223 dogs from an area of Natal, in the Rio Grande do Norte, Brazil, were studied to determine the association between comorbid tick-borne disease and Leishmania infection in this endemic area. The risk of Leishmania seropositivity was 1.68× greater in dogs with tick-borne disease seropositivity compared to those without (Adjusted RR: 1.68, 95% CI: 1.09-2.61, P = 0.019). A longitudinal study of 214 hunting dogs in the USA was conducted to determine the causal relationship between infection with tick-borne diseases and progression of VL. Hunting dogs were evaluated three times across a full tick season to detect incident infection with tick-borne diseases. A logistic regression model with generalized estimating equations to estimate the parameters was used to determine how exposure to tick-borne disease altered VL progression over these three time points when controlling for other variables. Dogs infected with three or more tick-borne diseases were 11× more likely to be associated with progression to clinical VL than dogs with no tick-borne disease (Adjusted RR: 11.64, 95% CI: 1.22-110.99, P = 0.03). Dogs with exposure to both Leishmania spp. and tick-borne diseases were five times more likely to die during the study period (RR: 4.85, 95% CI: 1.65-14.24, P = 0.0051). CONCLUSIONS Comorbid tick-borne diseases dramatically increased the likelihood that a dog had clinical L. infantum infection, making them more likely to transmit infection to sand flies and people. As an important consequence, reduction of tick-borne disease exposure through topical or oral insecticides may be an important way to reduce progression and transmissibility of Leishmania infection from the canine reservoir to people.
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Affiliation(s)
- Angela J. Toepp
- Department of Epidemiology, College of Public Health, University of Iowa, Iowa City, Iowa 52242 USA
- Center for Emerging Infectious Diseases, University of Iowa Research Park, Coralville, Iowa 52241 USA
| | - Glória R. G. Monteiro
- Institute of Tropical Medicine of Rio Grande do Norte, Federal University of Rio Grande do Norte, Natal, RN 59078-970 Brazil
| | - José F. V. Coutinho
- Institute of Tropical Medicine of Rio Grande do Norte, Federal University of Rio Grande do Norte, Natal, RN 59078-970 Brazil
| | - Adam Leal Lima
- Department of Epidemiology, College of Public Health, University of Iowa, Iowa City, Iowa 52242 USA
- Center for Emerging Infectious Diseases, University of Iowa Research Park, Coralville, Iowa 52241 USA
| | - Mandy Larson
- Department of Epidemiology, College of Public Health, University of Iowa, Iowa City, Iowa 52242 USA
- Center for Emerging Infectious Diseases, University of Iowa Research Park, Coralville, Iowa 52241 USA
| | - Geneva Wilson
- Department of Epidemiology, College of Public Health, University of Iowa, Iowa City, Iowa 52242 USA
- Center for Emerging Infectious Diseases, University of Iowa Research Park, Coralville, Iowa 52241 USA
| | - Tara Grinnage-Pulley
- Department of Epidemiology, College of Public Health, University of Iowa, Iowa City, Iowa 52242 USA
- Center for Emerging Infectious Diseases, University of Iowa Research Park, Coralville, Iowa 52241 USA
| | - Carolyne Bennett
- Department of Epidemiology, College of Public Health, University of Iowa, Iowa City, Iowa 52242 USA
- Center for Emerging Infectious Diseases, University of Iowa Research Park, Coralville, Iowa 52241 USA
| | - Kurayi Mahachi
- Department of Epidemiology, College of Public Health, University of Iowa, Iowa City, Iowa 52242 USA
- Center for Emerging Infectious Diseases, University of Iowa Research Park, Coralville, Iowa 52241 USA
| | - Bryan Anderson
- Department of Epidemiology, College of Public Health, University of Iowa, Iowa City, Iowa 52242 USA
- Center for Emerging Infectious Diseases, University of Iowa Research Park, Coralville, Iowa 52241 USA
| | - Marie V. Ozanne
- Department of Biostatistics, College of Public Health, University of Iowa, Iowa City, Iowa 52242 USA
| | - Michael Anderson
- Department of Epidemiology, College of Public Health, University of Iowa, Iowa City, Iowa 52242 USA
- Center for Emerging Infectious Diseases, University of Iowa Research Park, Coralville, Iowa 52241 USA
| | - Hailie Fowler
- Department of Epidemiology, College of Public Health, University of Iowa, Iowa City, Iowa 52242 USA
- Immunology Program, Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242 USA
| | - Molly Parrish
- Department of Epidemiology, College of Public Health, University of Iowa, Iowa City, Iowa 52242 USA
- Center for Emerging Infectious Diseases, University of Iowa Research Park, Coralville, Iowa 52241 USA
| | - Kelsey Willardson
- Department of Epidemiology, College of Public Health, University of Iowa, Iowa City, Iowa 52242 USA
- Center for Emerging Infectious Diseases, University of Iowa Research Park, Coralville, Iowa 52241 USA
| | - Jill Saucier
- IDEXX Laboratories Inc., One IDEXX Drive, Westbrook, Maine 04092 USA
| | - Phyllis Tyrell
- IDEXX Laboratories Inc., One IDEXX Drive, Westbrook, Maine 04092 USA
| | - Zachary Palmer
- Department of Geographical and Sustainability Sciences, College of Liberal Arts & Sciences, University of Iowa, Iowa City, Iowa 52242 USA
| | - Jesse Buch
- IDEXX Laboratories Inc., One IDEXX Drive, Westbrook, Maine 04092 USA
| | | | - Grant D. Brown
- Department of Biostatistics, College of Public Health, University of Iowa, Iowa City, Iowa 52242 USA
| | - Jacob J. Oleson
- Department of Biostatistics, College of Public Health, University of Iowa, Iowa City, Iowa 52242 USA
| | - Selma M. B. Jeronimo
- Institute of Tropical Medicine of Rio Grande do Norte, Federal University of Rio Grande do Norte, Natal, RN 59078-970 Brazil
| | - Christine A. Petersen
- Department of Epidemiology, College of Public Health, University of Iowa, Iowa City, Iowa 52242 USA
- Center for Emerging Infectious Diseases, University of Iowa Research Park, Coralville, Iowa 52241 USA
- Immunology Program, Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242 USA
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12
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Figueiredo FB, de Vasconcelos TCB, Madeira MDF, Menezes RC, Maia-Elkhoury ANS, Marcelino AP, Werneck GL. Validation of the Dual-path Platform chromatographic immunoassay (DPP® CVL rapid test) for the serodiagnosis of canine visceral leishmaniasis. Mem Inst Oswaldo Cruz 2018; 113:e180260. [PMID: 30379198 PMCID: PMC6216333 DOI: 10.1590/0074-02760180260] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Accepted: 09/25/2018] [Indexed: 11/21/2022] Open
Abstract
BACKGROUND Visceral leishmaniasis is a major public health challenge in South America, and dogs are its main urban reservoir. OBJECTIVE Validation of the canine Dual-path Platform immunoassay for canine visceral leishmaniasis (DPP® CVL) for a sample set composed of 1446 dogs from different Brazilian endemic areas. METHODS A well-defined reference standard by means of parasitological culture, immunohistochemistry, and histopathology was used. Animals were classified as asymptomatic, oligosymptomatic, or symptomatic. Sensitivity and specificity were assessed as a single set and in clinical groups. A reproducibility assessment of the tests was conducted using the Kappa (κ) index at three different laboratories (A, B, and C). FINDINGS Overall, 89% sensitivity and 70% specificity were obtained for the entire sample set. Analysis of the clinical groups showed a gradual decrease in the sensitivity and an increase in the specificity with the reduction of clinical signs in the dogs that were assessed, reaching a sensitivity of 75% (42.8-94.5%) among asymptomatic dogs and lower specificity of 56% (46.2-66.3%) among symptomatic dogs. Inter-laboratory agreement was substantial (κAB= 0.778; κAC= 0.645; κCB= 0.711). MAIN CONCLUSIONS The test performance is somewhat dependent on canine symptomatology, but such influence was less evident than in previous studies. Favourable results for sensitivity and specificity can be obtained even in asymptomatic animals; however, caution is needed in these evaluations, and the results suggest that the immunochromatographic test may be further improved for better investigation in asymptomatic dogs. The results obtained confirm the usefulness of DPP® CVL for application in serological surveys.
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Affiliation(s)
- Fabiano Borges Figueiredo
- Fundação Oswaldo Cruz-Fiocruz, Instituto Carlos Chagas, Laboratório de Biologia Celular, Curitiba, PR, Brasil
| | | | - Maria de Fátima Madeira
- Fundação Oswaldo Cruz-Fiocruz, Instituto Nacional de Infectologia, Laboratório de Vigilância em Leishmanioses, Rio de Janeiro, RJ, Brasil
| | - Rodrigo Caldas Menezes
- Fundação Oswaldo Cruz-Fiocruz, Instituto Nacional de infectologia, Laboratório de Pesquisa Clínica em Dermatozoonoses em Animais Domésticos, Rio de Janeiro, RJ, Brasil
| | - Ana Nilce Silveira Maia-Elkhoury
- Organização Pan-Americana de Saúde, Doenças Negligenciadas, Tropicais e Transmitidas por Vetores, Doenças Transmissíveis e Determinantes Ambientais de Saúde, Duque de Caxias, RJ, Brasil
| | | | - Guilherme L Werneck
- Universidade do Estado do Rio de Janeiro, Instituto de Medicina Social, Departamento de Epidemiologia, Rio de Janeiro, RJ, Brasil
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13
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Figueiredo FB, de Vasconcelos TCB, Madeira MDF, Menezes RC, Maia-Elkhoury ANS, Marcelino AP, Werneck GL. Validation of the Dual-path Platform chromatographic immunoassay (DPP® CVL rapid test) for the serodiagnosis of canine visceral leishmaniasis. Mem Inst Oswaldo Cruz 2018. [PMID: 30379198 PMCID: PMC6216333 DOI: 10.1590/0074-02760180206] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022] Open
Abstract
BACKGROUND Visceral leishmaniasis is a major public health challenge in South America, and dogs are its main urban reservoir. OBJECTIVE Validation of the canine Dual-path Platform immunoassay for canine visceral leishmaniasis (DPP® CVL) for a sample set composed of 1446 dogs from different Brazilian endemic areas. METHODS A well-defined reference standard by means of parasitological culture, immunohistochemistry, and histopathology was used. Animals were classified as asymptomatic, oligosymptomatic, or symptomatic. Sensitivity and specificity were assessed as a single set and in clinical groups. A reproducibility assessment of the tests was conducted using the Kappa (κ) index at three different laboratories (A, B, and C). FINDINGS Overall, 89% sensitivity and 70% specificity were obtained for the entire sample set. Analysis of the clinical groups showed a gradual decrease in the sensitivity and an increase in the specificity with the reduction of clinical signs in the dogs that were assessed, reaching a sensitivity of 75% (42.8-94.5%) among asymptomatic dogs and lower specificity of 56% (46.2-66.3%) among symptomatic dogs. Inter-laboratory agreement was substantial (κAB= 0.778; κAC= 0.645; κCB= 0.711). MAIN CONCLUSIONS The test performance is somewhat dependent on canine symptomatology, but such influence was less evident than in previous studies. Favourable results for sensitivity and specificity can be obtained even in asymptomatic animals; however, caution is needed in these evaluations, and the results suggest that the immunochromatographic test may be further improved for better investigation in asymptomatic dogs. The results obtained confirm the usefulness of DPP® CVL for application in serological surveys.
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Affiliation(s)
- Fabiano Borges Figueiredo
- Fundação Oswaldo Cruz-Fiocruz, Instituto Carlos Chagas, Laboratório de Biologia Celular, Curitiba, PR, Brasil
| | | | - Maria de Fátima Madeira
- Fundação Oswaldo Cruz-Fiocruz, Instituto Nacional de Infectologia, Laboratório de Vigilância em Leishmanioses, Rio de Janeiro, RJ, Brasil
| | - Rodrigo Caldas Menezes
- Fundação Oswaldo Cruz-Fiocruz, Instituto Nacional de infectologia, Laboratório de Pesquisa Clínica em Dermatozoonoses em Animais Domésticos, Rio de Janeiro, RJ, Brasil
| | - Ana Nilce Silveira Maia-Elkhoury
- Organização Pan-Americana de Saúde, Doenças Negligenciadas, Tropicais e Transmitidas por Vetores, Doenças Transmissíveis e Determinantes Ambientais de Saúde, Duque de Caxias, RJ, Brasil
| | | | - Guilherme L Werneck
- Universidade do Estado do Rio de Janeiro, Instituto de Medicina Social, Departamento de Epidemiologia, Rio de Janeiro, RJ, Brasil
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14
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Duthie MS, Lison A, Courtenay O. Advances toward Diagnostic Tools for Managing Zoonotic Visceral Leishmaniasis. Trends Parasitol 2018; 34:881-890. [PMID: 30131210 PMCID: PMC6168404 DOI: 10.1016/j.pt.2018.07.012] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Revised: 07/23/2018] [Accepted: 07/24/2018] [Indexed: 11/20/2022]
Abstract
Visceral leishmaniasis (VL) is a life-threatening outcome of Leishmania infantum or Leishmania donovani infection. Dogs are the primary domestic reservoir of L. infantum parasites, and ownership of infected dogs increases the risk of human VL. Controlling infection within dog populations is regarded as critical to VL management in endemic countries, both preventing progression of canine disease and limiting parasite transmission to humans and dogs. Here we discuss various strategies that are used to diagnose canine visceral leishmaniasis (CVL) and the possibilities of adapting these for use within population screening and control programs. In addition, given the variable transmissibility of L. infantum to the sand fly vector, we outline some possibilities for the preferential identification of 'super-spreader' dogs among the overall infected population.
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Affiliation(s)
- Malcolm S Duthie
- Infectious Disease Research Institute, 1616 Eastlake Ave E, Suite 400, Seattle, WA 98102, USA.
| | - Aurore Lison
- School of Life Sciences, University of Warwick, Coventry, UK
| | - Orin Courtenay
- School of Life Sciences, University of Warwick, Coventry, UK
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15
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Toepp A, Larson M, Wilson G, Grinnage-Pulley T, Bennett C, Leal-Lima A, Anderson B, Parrish M, Anderson M, Fowler H, Hinman J, Kontowicz E, Jefferies J, Beeman M, Buch J, Saucier J, Tyrrell P, Gharpure R, Cotter C, Petersen C. Randomized, controlled, double-blinded field trial to assess Leishmania vaccine effectiveness as immunotherapy for canine leishmaniosis. Vaccine 2018; 36:6433-6441. [PMID: 30219369 DOI: 10.1016/j.vaccine.2018.08.087] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2018] [Revised: 08/03/2018] [Accepted: 08/04/2018] [Indexed: 10/28/2022]
Abstract
Better tools are necessary to eliminate visceral leishmaniasis (VL). Modeling studies for regional Leishmania elimination indicate that an effective vaccine is a critical tool. Dogs are the reservoir host of L. infantum in Brazil and the Mediterranean basin, and therefore are an important target for public health interventions as well as a relevant disease model for human VL. No vaccine has been efficacious as an immunotherapy to prevent progression of already diagnostically positive individuals to symptomatic leishmaniasis. We performed a double-blinded, block-randomized, placebo-controlled, vaccine immunotherapy trial testing the efficacy of a recombinant Leishmania A2 protein, saponin-adjuvanted, vaccine, LeishTec®, in owned hunting dogs infected with L. infantum. The primary outcome was reduction of clinical progression, with reduction of mortality as a secondary outcome. Vaccination as an immunotherapy reduced the risk of progression to clinically overt leishmaniasis by 25% in asymptomatic dogs (RR: 1.33 95% C.I. 1.009-1.786 p-value: 0.0450). Receiving vaccine vs. placebo reduced all-cause mortality in younger asymptomatic dogs by 70% (RR: 3.19 95% C.I.: 1.185-8.502 p-value = 0.0245). Vaccination of infected-healthy animals with an anti-Leishmania vaccine significantly reduced clinical progression and decreased all-cause mortality. Use of vaccination in infected-healthy dogs can be a tool for Leishmania control.
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Affiliation(s)
- Angela Toepp
- Department of Epidemiology, College of Public Health, University of Iowa, Iowa City, IA 52242, USA; Center for Emerging Infectious Diseases, University of Iowa Research Park, Coralville, IA 52241, USA
| | - Mandy Larson
- Department of Epidemiology, College of Public Health, University of Iowa, Iowa City, IA 52242, USA; Center for Emerging Infectious Diseases, University of Iowa Research Park, Coralville, IA 52241, USA
| | - Geneva Wilson
- Department of Epidemiology, College of Public Health, University of Iowa, Iowa City, IA 52242, USA; Center for Emerging Infectious Diseases, University of Iowa Research Park, Coralville, IA 52241, USA
| | - Tara Grinnage-Pulley
- Department of Epidemiology, College of Public Health, University of Iowa, Iowa City, IA 52242, USA; Center for Emerging Infectious Diseases, University of Iowa Research Park, Coralville, IA 52241, USA
| | - Carolyne Bennett
- Department of Epidemiology, College of Public Health, University of Iowa, Iowa City, IA 52242, USA; Center for Emerging Infectious Diseases, University of Iowa Research Park, Coralville, IA 52241, USA
| | - Adam Leal-Lima
- Department of Epidemiology, College of Public Health, University of Iowa, Iowa City, IA 52242, USA; Center for Emerging Infectious Diseases, University of Iowa Research Park, Coralville, IA 52241, USA
| | - Bryan Anderson
- Department of Epidemiology, College of Public Health, University of Iowa, Iowa City, IA 52242, USA
| | - Molly Parrish
- Department of Epidemiology, College of Public Health, University of Iowa, Iowa City, IA 52242, USA; Center for Emerging Infectious Diseases, University of Iowa Research Park, Coralville, IA 52241, USA
| | - Michael Anderson
- Department of Epidemiology, College of Public Health, University of Iowa, Iowa City, IA 52242, USA
| | - Hailie Fowler
- Department of Epidemiology, College of Public Health, University of Iowa, Iowa City, IA 52242, USA
| | - Jessica Hinman
- Department of Epidemiology, College of Public Health, University of Iowa, Iowa City, IA 52242, USA
| | - Eric Kontowicz
- Department of Epidemiology, College of Public Health, University of Iowa, Iowa City, IA 52242, USA
| | | | | | - Jesse Buch
- IDEXX Laboratories Inc., Westbrook, ME, USA
| | | | | | - Radhika Gharpure
- Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD 21210, USA
| | - Caitlin Cotter
- Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD 21210, USA
| | - Christine Petersen
- Department of Epidemiology, College of Public Health, University of Iowa, Iowa City, IA 52242, USA; Center for Emerging Infectious Diseases, University of Iowa Research Park, Coralville, IA 52241, USA. http://petersen.lab.uiowa.edu/
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16
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Toepp AJ, Schaut RG, Scott BD, Mathur D, Berens AJ, Petersen CA. Leishmania incidence and prevalence in U.S. hunting hounds maintained via vertical transmission. Vet Parasitol Reg Stud Reports 2017; 10:75-81. [PMID: 31014604 DOI: 10.1016/j.vprsr.2017.08.011] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Revised: 07/25/2017] [Accepted: 08/17/2017] [Indexed: 11/30/2022]
Abstract
Leishmania is the causative agent of leishmaniasis, a deadly protozoan disease which affects over 1 million people each year. Autochthonous cases of canine leishmaniasis are generally associated with tropical and subtropical climatic zones. However, in 1999, U.S. hunting dogs were found to have leishmaniasis with no history of travel outside the country. Transmission of this disease was found to be primarily vertical. In endemic areas, dogs are a dominant domestic reservoir host for Leishmania infantum. This study evaluated L. infantum infection prevalence and incidence within US dogs tested over a nine-year span (2007-2015). This investigation used both passive and active surveillance, following an initial outbreak investigation by the Centers for Disease Control. L. infantum infection incidence and prevalence over time and across regions were examined to evaluate whether transmission was sufficient to maintain ongoing infection within this population. These studies also established whether this disease is becoming more or less prominent within this reservoir host, dogs. There was no significant difference between prevalence and incidence rates via as measured by passive vs. active surveillance. Although due to fluctuations in sample submission there were significant changes in both incidence and prevalence of L. infantum in US hunting dogs over this nine year span, these differences were not outside of the interquartile range and therefore there is likely to be a steady-state of transmission within U.S. dogs. Based on these findings, if vertical transmission is the primary means of L. infantum spread in U.S. dogs, with appropriate husbandry and infection control procedures, elimination of L. infantum from US dogs could be possible.
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Affiliation(s)
- Angela J Toepp
- College of Public Health, Center for Emerging Infectious Diseases, University of Iowa, Iowa City, IA, USA
| | - Robert G Schaut
- College of Public Health, Center for Emerging Infectious Diseases, University of Iowa, Iowa City, IA, USA
| | - Benjamin D Scott
- College of Public Health, Center for Emerging Infectious Diseases, University of Iowa, Iowa City, IA, USA
| | - Divida Mathur
- Bioinformatics and Computational Biology Lab, Iowa State University, Ames, Iowa, USA
| | - Ali J Berens
- Bioinformatics and Computational Biology Lab, Iowa State University, Ames, Iowa, USA
| | - Christine A Petersen
- College of Public Health, Center for Emerging Infectious Diseases, University of Iowa, Iowa City, IA, USA.
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