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Ibarra-Meneses AV, Corbeil A, Wagner V, Onwuchekwa C, Fernandez-Prada C. Identification of asymptomatic Leishmania infections: a scoping review. Parasit Vectors 2022; 15:5. [PMID: 34983616 PMCID: PMC8727076 DOI: 10.1186/s13071-021-05129-y] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Accepted: 12/11/2021] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Asymptomatic Leishmania infection may play an important role in the transmission of the parasite in endemic areas. At present there is no consensus on the definition of asymptomatic Leishmania infection, nor is there a safe and accessible gold standard test for its identification. METHODS This paper presents a scoping review to summarize definitions of asymptomatic Leishmania infection found in the literature, as well as to detail the approach (molecular, serological, cellular, and/or parasitological tests) used by researchers to identify this asymptomatic population. A scoping review of published and gray literature related to asymptomatic Leishmania infection was conducted; retrieved citations were screened based on predefined eligibility criteria, and relevant data items were extracted from eligible articles. The analysis is descriptive and is presented using tables, figures, and thematic narrative synthesis. RESULTS We conducted a screening of 3008 articles, of which 175 were selected for the full review. Of these articles, we selected 106 that met the inclusion criteria. These articles were published between 1991 and 2021, and in the last 5 years, up to 38 articles were reported. Most of the studies were conducted in Brazil (26%), Spain (14%), India (12%), Bangladesh (10%), and Ethiopia (7%). Of the studies, 84.9% were conducted in the immunocompetent population, while 15.1% were conducted in the immunosuppressed population (HIV, immunosuppressive drugs, and organ transplantation population). We report 14 different techniques and 10 strategies employed by researchers to define asymptomatic Leishmania infection in an endemic area. CONCLUSIONS The definition of asymptomatic Leishmania infection is not unified across the literature, but often includes the following criteria: residence (or extended stay) in a Leishmania-endemic area, no reported signs/symptoms compatible with leishmaniasis, and positive on a combination of serological, molecular, cellular, and/or parasitological tests. Caution is recommended when comparing results of different studies on the subject of asymptomatic infections, as the reported prevalence cannot be confidently compared between areas due to the wide variety of tests employed by research groups. More research on the importance of asymptomatic immunosuppressed and immunocompetent Leishmania-positive populations in leishmaniasis epidemiology is required.
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Affiliation(s)
- Ana Victoria Ibarra-Meneses
- Département de Pathologie et Microbiologie, Faculté de Médecine Vétérinaire, Université de Montréal, Saint-Hyacinthe, QC, Canada.,The Research Group on Infectious Diseases in Production Animals (GREMIP), Faculty of Veterinary Medicine, Université de Montréal, Saint Hyacinthe, Canada
| | - Audrey Corbeil
- Département de Pathologie et Microbiologie, Faculté de Médecine Vétérinaire, Université de Montréal, Saint-Hyacinthe, QC, Canada.,The Research Group on Infectious Diseases in Production Animals (GREMIP), Faculty of Veterinary Medicine, Université de Montréal, Saint Hyacinthe, Canada
| | - Victoria Wagner
- Département de Pathologie et Microbiologie, Faculté de Médecine Vétérinaire, Université de Montréal, Saint-Hyacinthe, QC, Canada.,The Research Group on Infectious Diseases in Production Animals (GREMIP), Faculty of Veterinary Medicine, Université de Montréal, Saint Hyacinthe, Canada
| | - Chukwuemeka Onwuchekwa
- Barcelona Institute for Global Health (ISGlobal), Hospital Clínic, University of Barcelona, Barcelona, Spain
| | - Christopher Fernandez-Prada
- Département de Pathologie et Microbiologie, Faculté de Médecine Vétérinaire, Université de Montréal, Saint-Hyacinthe, QC, Canada. .,The Research Group on Infectious Diseases in Production Animals (GREMIP), Faculty of Veterinary Medicine, Université de Montréal, Saint Hyacinthe, Canada.
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Mody RM, Lakhal-Naouar I, Sherwood JE, Koles NL, Shaw D, Bigley DP, Co EMA, Copeland NK, Jagodzinski LL, Mukbel RM, Smiley RA, Duncan RC, Kamhawi S, Jeronimo SMB, DeFraites RF, Aronson NE. Asymptomatic Visceral Leishmania infantum Infection in US Soldiers Deployed to Iraq. Clin Infect Dis 2020; 68:2036-2044. [PMID: 30239631 DOI: 10.1093/cid/ciy811] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2018] [Accepted: 09/14/2018] [Indexed: 12/28/2022] Open
Abstract
BACKGROUND Visceral leishmaniasis (VL), due to Leishmania infantum, is a persistent intracellular parasitic infection transmitted by the bite of infected sand flies. Symptomatic VL has been reported in U.S. soldiers with Iraq deployment. Untreated symptomatic VL can be fatal; asymptomatic VL (AVL) may establish a lifelong risk of reactivation. We report prevalence and AVL risk factors in Operation Iraqi Freedom (OIF) deployers during 2002-11. METHODS Healthy soldiers exposed to VL endemic areas in Iraq and 50 controls who never traveled to endemic regions were recruited through military healthcare facilities (2015-17). Responses to a risk factor survey and blood samples were obtained. Leishmania research diagnostics utilized included enzyme-linked immunosorbent assay (ELISA), rk39 test strips, quantitative polymerase chain reaction (PCR), and interferon gamma release (IGRA) assays. Statistical analyses included Fisher exact test, Pearson χ2 test, Mann-Whitney U test, and logistic regression. RESULTS 200 deployed subjects were enrolled, mostly males (84.0%), of white ethnicity (79.0%), and median age 41 (range 24-61) years. 64% were seropositive for Phlebotomus alexandri saliva antibodies. Prevalence of AVL (any positive test result) was 39/200 (19.5%, 95% confidence interval 14.4%-25.8%). Two (1.0%) PCR, 10 (5%) ELISA, and 28 (14%) IGRA samples were positive. Travel to Ninewa governorate increased risk for AVL (P = .01). CONCLUSION AVL was identified in 19.5% of OIF deployers; travel to northwest Iraq correlated with infection. Further studies are needed to inform risk for reactivation VL in US veterans and to target additional blood safety and surveillance measures.
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Affiliation(s)
- Rupal M Mody
- Infectious Diseases Department, William Beaumont Army Medical Center, El Paso, Texas
| | - Ines Lakhal-Naouar
- Infectious Diseases Division, Uniformed Services University of the Health Sciences
| | - Jeffrey E Sherwood
- Infectious Diseases Department, William Beaumont Army Medical Center, El Paso, Texas
| | - Nancy L Koles
- Infectious Diseases Division, Uniformed Services University of the Health Sciences
| | - Dutchabong Shaw
- Clinical Research Unit, Uniformed Services University of the Health Sciences, Bethesda, Maryland
| | | | - Edgie-Mark A Co
- Internal Medicine Department, William Beaumont Army Medical Center, El Paso, Texas
| | | | | | - Rami M Mukbel
- Department of Basic Veterinary Sciences, Jordan University of Science and Technology, Irbid, Jordan
| | - Rebecca A Smiley
- Department of Clinical Investigations, William Beaumont Army Medical Center, El Paso, Texas
| | - Robert C Duncan
- Division of Emerging and Transfusion Transmitted Diseases, Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring
| | - Shaden Kamhawi
- Vector Molecular Biology Section, Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, Rockville, Maryland
| | - Selma M B Jeronimo
- Department of Biochemistry and Institute of Tropical Medicine at Rio Grande do Norte, Natal.,National Institute of Science and Technology of Tropical Diseases, Salvador, Bahia, Brazil
| | - Robert F DeFraites
- Department of Preventive Medicine and Biostatistics, Uniformed Services University of the Health Sciences, Bethesda, Maryland
| | - Naomi E Aronson
- Infectious Diseases Division, Uniformed Services University of the Health Sciences
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Prospection of immunological biomarkers for characterization and monitoring of asymptomatic Leishmania ( Leishmania) infantum infection. Parasitology 2020; 147:1124-1132. [PMID: 32460936 DOI: 10.1017/s0031182020000852] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
In areas endemic for Leishmania infantum, an asymptomatic infection may be an indicator of the extent of transmission. The main goal of this study was to evaluate the applicability of measuring circulating immunological biomarkers as an alternative strategy to characterize and monitor L. infantum asymptomatic infections in combination with serological methods. To this end, 179 children from a region endemic for visceral leishmaniasis (VL), aged 1-10 years old, selected from a cross-sectional study, were identified as asymptomatic (n = 81) or uninfected (n = 98) by qPCR and/or serological tests (ELISA using L. infantum soluble antigen and rK39), and, together with serum samples of children diagnosed with VL (n = 43), were subjected to avidity tests and cytokine levels measurement. Avidity rates (AR) ranging from 41 to 70% were found in 29 children (66%) from the asymptomatic group. On the other hand, high AR (above 70%) were observed in 27 children (64%) from the VL group. Logistic Regression and Classification and Regression Tree (CART) analyses demonstrated that lower AR and IFN-γ production associated with higher IL-17A levels were hallmarks in asymptomatic L. infantum infections. Therefore, this study proposes an association of immunological biomarkers that can be used as a complementary strategy for the characterization and monitoring of asymptomatic VL infections in children living in endemic areas.
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Evaluation of methods for detection of asymptomatic individuals infected with Leishmania infantum in the state of Piauí, Brazil. PLoS Negl Trop Dis 2019; 13:e0007493. [PMID: 31260440 PMCID: PMC6625727 DOI: 10.1371/journal.pntd.0007493] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Revised: 07/12/2019] [Accepted: 05/24/2019] [Indexed: 01/29/2023] Open
Abstract
BACKGROUND Visceral Leishmaniasis in humans presents with fever, anemia, and splenomegaly and can be lethal if not treated. Nevertheless, the majority of Leishmania infantum-infected individuals does not manifest symptoms and remain so provided they are not immunosuppressed. In this work, the performance of different tests was evaluated to detect asymptomatic individuals who were living in Teresina, Piauí state, Brazil, an endemic area for VL. METHODOLOGY L. infantum-specific antibodies were detected by ELISA and two different rapid immunochromatographic (IC) diagnostic tests, Kalazar Detect and OnSite, and parasitic loads were detected by real time PCR [qPCR]. Additionally, we measured levels of the biomarkers monokine induced by IFN-γ (MIG) and IFN-γ-induced protein 10 (IP-10) before and after stimulation of whole blood with soluble Leishmania antigen [SLA]. PRINCIPAL FINDINGS Kalazar Detect and OnSite detected, respectively, 76% and 64% of patients presenting with active Visceral Leishmaniasis; 50% and 57% of patients remained positive in these tests, respectively, after treatment. Of the healthy participants in the study who were living in the endemic area, only 1.7% were positive with both of the IC tests. On the other hand, reactivity in ELISA tests revealed that 13% of these individuals presented asymptomatic infections; among VL patients, 84% presenting with active disease were reactive in ELISA, and after treatment, 55.5% were seropositive. L. infantum DNA was present in the blood of 37.9% of infected individuals living in the endemic area, while IP-10 and MIG biomarkers were detected in 26.7% of them. The greatest concordance of positivity occurred between ELISA and qPCR. CONCLUSION The association of different techniques can detect asymptomatic infections, however, more research is necessary to develop ideal biomarkers that are simple to use in the clinic and in field studies in areas endemic for Visceral Leishmaniasis.
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da Rocha ICM, Dos Santos LHM, Coura-Vital W, da Cunha GMR, Magalhães FDC, da Silva TAM, Morais MHF, Oliveira E, Reis IA, Carneiro M. Effectiveness of the Brazilian Visceral Leishmaniasis Surveillance and Control Programme in reducing the prevalence and incidence of Leishmania infantum infection. Parasit Vectors 2018; 11:586. [PMID: 30419944 PMCID: PMC6233359 DOI: 10.1186/s13071-018-3166-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2018] [Accepted: 10/24/2018] [Indexed: 12/02/2022] Open
Abstract
Background Control strategies adopted by the Brazilian Visceral Leishmaniasis Surveillance and Control Programme (VLSCP) include identifying and culling seropositive infected dogs, early diagnosis and treatment of human cases, chemical control of the vector and population awareness. This study evaluated the effectiveness of the VLSCP on the prevalence and incidence rates of Leishmania infantum in children residing in areas under different VLSCP intervention times. Methods A quasi-experimental epidemiological study with a panel (two cross-sectional) and a concurrent cohort was performed in three areas of Belo Horizonte, southeast Brazil. The first cross-sectional study (I) was carried out with 1875 children, 478 of which were enrolled in the cohort study. In the second cross-sectional study (II), 413 additional children were included, totalizing 891 children. Laboratory diagnosis was performed by ELISA-rK39. Analyses included multilevel logistic and Poisson regression models. Results The incidence rates of L. infantum infection were: 14.4% in the area where VLSCP intervention was initiated in 2006 (AI2006); 21.1% in the area where intervention was initiated in 2008 (AI2008); and 11.6% in the area where intervention was initiated in 2010 (AI2010 - control area). A follow-up period of 24 months showed that the persons-time incidence rates in AI2006, AI2008, and AI2010 were: 6.2/100, 10/100, and 5.6/100 persons/24 months, respectively. The final prevalence rates of infection (cross-sectional II - in 2012), compared to the initial rates (cross-sectional I - in 2010), increased 83.7% in AI2006, 74.1% in AI2008, and decreased 5% in AI2010. Analysis of the effectiveness revealed that children residing in AI2008 are more likely to be infected (OR = 1.84; 95% CI: 1.06-3.23) and present a higher risk of infection (IRR = 1.76; 95% CI: 1.05-2.95) compared to those in AI2010. No statistically significant differences were observed in asymptomatic infection (OR and IRR) in AI2006 compared to AI2010. Conclusions The VLSCP was not effective at controlling L. infantum infection in areas where interventions had respectively been carried out for six and four years. However, it is unclear what the consequences in terms of human infection and diseases would be in the absence of the VLSCP. Efforts to improve the effectiveness of control measures remain a necessary priority. Electronic supplementary material The online version of this article (10.1186/s13071-018-3166-0) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Iara Caixeta Marques da Rocha
- Laboratório de Epidemiologia das Doenças Infecciosas e Parasitárias, Departamento de Parasitologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil.,Secretaria Municipal de Saúde de Belo Horizonte, Belo Horizonte, Minas Gerais, Brazil
| | - Letícia Helena Marques Dos Santos
- Laboratório de Epidemiologia das Doenças Infecciosas e Parasitárias, Departamento de Parasitologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Wendel Coura-Vital
- Departamento de Análises Clínicas, Pós-graduação em Ciências Farmacêuticas, Escola de Farmácia, Universidade Federal de Ouro Preto, Ouro Preto, Minas Gerais, Brazil.,Pós-graduação em Ciências Biológicas, Núcleo de Pesquisa em Ciências Biológicas, Universidade Federal de Ouro Preto, Ouro Preto, Minas Gerais, Brazil
| | - Gisele Macedo Rodrigues da Cunha
- Laboratório de Epidemiologia das Doenças Infecciosas e Parasitárias, Departamento de Parasitologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Fernanda do Carmo Magalhães
- Laboratório de Epidemiologia das Doenças Infecciosas e Parasitárias, Departamento de Parasitologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Thais Almeida Marques da Silva
- Laboratório de Epidemiologia das Doenças Infecciosas e Parasitárias, Departamento de Parasitologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil.,Instituto de Ensino e Pesquisa da Santa Casa Belo Horizonte, Belo Horizonte, Minas Gerais, Brazil
| | | | - Edward Oliveira
- Laboratório de Pesquisas Clínicas, Instituto René Rachou, Fundação Oswaldo Cruz, Belo Horizonte, Minas Gerais, Brazil
| | - Ilka Afonso Reis
- Departamento de Estatística, Instituto de Ciências Exatas, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Mariângela Carneiro
- Laboratório de Epidemiologia das Doenças Infecciosas e Parasitárias, Departamento de Parasitologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil. .,Pós-graduação em Ciências da Saúde: Infectologia e Medicina Tropical, Faculdade de Medicina, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil.
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Development and Validation of a PCR-ELISA for the Diagnosis of Symptomatic and Asymptomatic Infection by Leishmania (Leishmania) infantum. J Trop Med 2017; 2017:7364854. [PMID: 28163725 PMCID: PMC5253510 DOI: 10.1155/2017/7364854] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Accepted: 12/07/2016] [Indexed: 11/17/2022] Open
Abstract
A kDNA PCR enzyme-linked immunosorbent assay (kDNA PCR-ELISA) for the diagnosis of human visceral leishmaniasis (HVL) was developed. The detection limit of the reaction, precision measurements, and cut-off of the kDNA PCR-ELISA were defined in a proof-of-concept phase. A reference strain of Leishmania (Leishmania) infantum and a bank of 14 peripheral blood samples from immunocompetent patients with VL were characterized using techniques considered gold standards, and 11 blood samples obtained from healthy individuals of an endemic area were also assessed. Phase II evaluation determined the performance of the assay in peripheral blood samples from 105 patients with VL (adults and children), 25 patients with Leishmania/HIV coinfection, 40 healthy individuals, and 33 asymptomatic individuals living in endemic areas. The kDNA PCR-ELISA exhibited satisfactory precision, with a detection limit of 0.07 fg of DNA from L. (L.) infantum and 1 parasite/mL blood. The overall sensitivity of the assay for all groups studied was 100% (95% confidence interval [CI]: 97.1–100%), and the specificity was 95% (95% CI: 83.5–98.6%). The kDNA PCR-ELISA was shown to be a useful tool for VL symptomatic and asymptomatic individuals diagnosis and its use in endemic countries may help monitor control interventions.
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Leishmania infantum: illness, transmission profile and risk factors for asymptomatic infection in an endemic metropolis in Brazil. Parasitology 2016; 144:546-556. [PMID: 27894365 DOI: 10.1017/s0031182016002134] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
To evaluate the distribution of asymptomatic infection by Leishmania infantum in a metropolis in Brazil with different relative risks (RRs) for disease and risk factors associated with the infection, an ecological study was conducted using a Bayesian approach to estimate the RR of human visceral leishmaniasis (HVL) based on cases between 2008 and 2011. The areas were categorized and selected according to disease incidence: low (area-1), medium (area-2) and high (area-3). Cross-sectional study enrolling 935 children was used to estimate the prevalence of infection by L. infantum. Volunteers from these three areas were tested for L. infantum infection by ELISA (rK39 and soluble antigens). Infection prevalence rates were estimated and compared with the RR of disease. Multilevel logistic regression model evaluated the relationship between infection and the analysed variables. The RR of HVL was distributed heterogeneously in the municipality. The infection prevalence rates were: 34·9% in area-1; 29·3% in area-2; and 33·6% in area-3, with no significant differences between these areas. The variables 'Presence of backyards in the neighbourhood' and 'Younger children' were associated with L. infantum infection. We conclude that infection by L. infantum affects a significant proportion of the infant population regardless of the RR of disease.
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Rock KS, Quinnell RJ, Medley GF, Courtenay O. Progress in the Mathematical Modelling of Visceral Leishmaniasis. ADVANCES IN PARASITOLOGY 2016; 94:49-131. [PMID: 27756459 DOI: 10.1016/bs.apar.2016.08.001] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The leishmaniases comprise a complex of diseases characterized by clinical outcomes that range from self-limiting to chronic, and disfiguring and stigmatizing to life threatening. Diagnostic methods, treatments, and vector and reservoir control options exist, but deciding the most effective interventions requires a quantitative understanding of the population level infection and disease dynamics. The effectiveness of any set of interventions has to be determined within the context of operational conditions, including economic and political commitment. Mathematical models are the best available tools for studying quantitative systems crossing disciplinary spheres (biology, medicine, economics) within environmental and societal constraints. In 2005, the World Health Assembly and government health ministers of India, Nepal, and Bangladesh signed a Memorandum of Understanding to eliminate the life threatening form of leishmaniasis, visceral leishmaniasis (VL), on the Indian subcontinent by 2015 through a combination of early case detection, improved treatments, and vector control. The elimination target is <1 case/10,000 population at the district or subdistrict level compared to the current 20/10,000 in the regions of highest transmission. Towards this goal, this chapter focuses on mathematical models of VL, and the biology driving those models, to enable realistic predictions of the best combination of interventions. Several key issues will be discussed which have affected previous modelling of VL and the direction future modelling may take. Current understanding of the natural history of disease, immunity (and loss of immunity), and stages of infection and their durations are considered particularly for humans, and also for dogs. Asymptomatic and clinical infection are discussed in the context of their relative roles in Leishmania transmission, as well as key components of the parasite-sandfly-vector interaction and intervention strategies including diagnosis, treatment and vector control. Gaps in current biological knowledge and potential avenues to improve model structures and mathematical predictions are identified. Underpinning the marriage between biology and mathematical modelling, the content of this chapter represents the first step towards developing the next generation of models for VL.
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Affiliation(s)
- K S Rock
- University of Warwick, Coventry, United Kingdom
| | | | - G F Medley
- London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - O Courtenay
- University of Warwick, Coventry, United Kingdom
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Pessoa-E-Silva R, Mendonça Trajano-Silva LA, Lopes da Silva MA, da Cunha Gonçalves-de-Albuquerque S, de Goes TC, Silva de Morais RC, Lopes de Melo F, de Paiva-Cavalcanti M. Evaluation of urine for Leishmania infantum DNA detection by real-time quantitative PCR. J Microbiol Methods 2016; 131:34-41. [PMID: 27713020 DOI: 10.1016/j.mimet.2016.10.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2016] [Revised: 09/05/2016] [Accepted: 10/01/2016] [Indexed: 11/17/2022]
Abstract
The availability of some sorts of biological samples which require noninvasive collection methods has led to an even greater interest in applying molecular biology on visceral leishmaniasis (VL) diagnosis, since these samples increase the safety and comfort of both patients and health professionals. In this context, this work aimed to evaluate the suitability of the urine as a specimen for Leishmania infantum kinetoplast DNA detection by real-time quantitative PCR (qPCR). Subsequent to the reproducibility analysis, the detection limit of the qPCR assay was set at 5fg (~0.025 parasites) per μL of urine. From the comparative analysis performed with a set of diagnostic criteria (serological and molecular reference tests), concordance value of 96.08% was obtained (VL-suspected and HIV/AIDS patients, n=51) (P>0.05). Kappa coefficient (95% CI) indicated a good agreement between the test and the set of diagnostic criteria (k=0.778±0.151). The detection of Leishmania DNA in urine by qPCR was possible in untreated individuals, and in those with or without suggestive renal impairment. Fast depletion of the parasite's DNA in urine after treatment (from one dose of meglumine antimoniate) was suggested by negative qPCR results, thus indicating it as a potential alternative specimen to follow up the efficacy of therapeutic approaches. Even when evaluated in a clinically heterogeneous set of patients, the urine showed good prospect as sample for VL diagnosis by qPCR, also indicating a good negative predictive value for untreated suspected patients.
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Affiliation(s)
- Rômulo Pessoa-E-Silva
- Aggeu Magalhães Research Center, Av. Moraes Rego, Cidade Universitária, CEP 50670-420 Recife, PE, Brazil; Public Health's Central Laboratory Dr. Milton Bezerra Sobral (LACEN-PE), Praça Oswaldo Cruz, S/N, Soledade, CEP 50050-215 Recife, PE, Brazil.
| | | | | | - Suênia da Cunha Gonçalves-de-Albuquerque
- Aggeu Magalhães Research Center, Av. Moraes Rego, Cidade Universitária, CEP 50670-420 Recife, PE, Brazil; Public Health's Central Laboratory Dr. Milton Bezerra Sobral (LACEN-PE), Praça Oswaldo Cruz, S/N, Soledade, CEP 50050-215 Recife, PE, Brazil.
| | - Tayná Correia de Goes
- Aggeu Magalhães Research Center, Av. Moraes Rego, Cidade Universitária, CEP 50670-420 Recife, PE, Brazil.
| | | | - Fábio Lopes de Melo
- Aggeu Magalhães Research Center, Av. Moraes Rego, Cidade Universitária, CEP 50670-420 Recife, PE, Brazil.
| | - Milena de Paiva-Cavalcanti
- Aggeu Magalhães Research Center, Av. Moraes Rego, Cidade Universitária, CEP 50670-420 Recife, PE, Brazil.
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Accurate Serodetection of Asymptomatic Leishmania donovani Infection by Use of Defined Antigens. J Clin Microbiol 2016; 54:1025-30. [PMID: 26842701 PMCID: PMC4809943 DOI: 10.1128/jcm.02620-15] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2015] [Accepted: 01/08/2016] [Indexed: 12/16/2022] Open
Abstract
Infection with Leishmania donovani is typically asymptomatic, but a significant number of individuals may progress to visceral leishmaniasis (VL), a deadly disease that threatens 200 million people in areas where it is endemic. While diagnosis of acute VL has been simplified by the use of cost-effective confirmatory serological tests, similar standardized tools are not widely available for detecting asymptomatic infection, which can be 4 to 20 times more prevalent than active disease. A simple and accurate serological test that is capable of detecting asymptomatic L. donovani infection will be useful for surveillance programs targeting VL control and elimination. To address this unmet need, we evaluated recombinant antigens for their ability to detect serum antibodies in 104 asymptomatic L. donovani-infected individuals (qualified as positive for L. donovani-specific antibodies by direct agglutination test [DAT]) from the Mymensingh district of Bangladesh where VL is hyperendemic. The novel proteins rKR95 and rTR18 possessed the greatest potential and detected 69% of DAT-positive individuals, with rKR95 being more robust in reactivity. Agreement in results for individuals with high DAT responses, who are more likely to progress to VL disease, was 74%. When considered along with rK39, a gold standard antigen that is used to confirm clinical diagnosis of VL but that is now becoming widely used for surveillance, rKR95 and rTR18 conferred a sensitivity of 84% based on a theoretical combined estimate. Our data indicate that incorporating rKR95 and rTR18 with rK39 in serological tests amenable to rapid or high-throughput screening may enable simple and accurate detection of asymptomatic infection. Such tests will be important tools to measure L. donovani infection rates, a primary goal in surveillance and a critical measurement with which to assess elimination programs.
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Rosales-Chilama M, Gongora RE, Valderrama L, Jojoa J, Alexander N, Rubiano LC, Cossio A, Adams ER, Saravia NG, Gomez MA. Parasitological Confirmation and Analysis of Leishmania Diversity in Asymptomatic and Subclinical Infection following Resolution of Cutaneous Leishmaniasis. PLoS Negl Trop Dis 2015; 9:e0004273. [PMID: 26659114 PMCID: PMC4684356 DOI: 10.1371/journal.pntd.0004273] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2015] [Accepted: 11/10/2015] [Indexed: 12/21/2022] Open
Abstract
Background The contribution of individuals with subclinical infection to the transmission and endemicity of cutaneous leishmaniasis (CL) is unknown. Immunological evidence of exposure to Leishmania in residents of endemic areas has been the basis for defining the human population with asymptomatic infection. However, parasitological confirmation of subclinical infection is lacking. Methods We investigated the presence and viability of Leishmania in blood and non-invasive mucosal tissue samples from individuals with immunological evidence of subclinical infection in endemic areas for CL caused by Leishmania (Viannia) in Colombia. Detection of Leishmania kDNA was conducted by PCR-Southern Blot, and parasite viability was confirmed by amplification of parasite 7SLRNA gene transcripts. A molecular tool for genetic diversity analysis of parasite populations causing persistent subclinical infection based on PCR amplification and sequence analysis of an 82bp region between kDNA conserved blocks 1 and 2 was developed. Principal Findings Persistent Leishmania infection was demonstrated in 40% (46 of 114) of leishmanin skin test (LST) positive individuals without active disease; parasite viability was established in 59% of these (27 of 46; 24% of total). Parasite burden quantified from circulating blood monocytes, nasal, conjunctival or tonsil mucosal swab samples was comparable, and ranged between 0.2 to 22 parasites per reaction. kDNA sequences were obtained from samples from 2 individuals with asymptomatic infection and from 26 with history of CL, allowing genetic distance analysis that revealed diversity among sequences and clustering within the L. (Viannia) subgenus. Conclusions Our results provide parasitological confirmation of persistent infection among residents of endemic areas of L. (Viannia) transmission who have experienced asymptomatic infection or recovered from CL, revealing a reservoir of infection that potentially contributes to the endemicity and transmission of disease. kDNA genotyping establishes proof-of-principle of the feasibility of genetic diversity analysis in previously inaccessible and unexplored parasite populations in subclinically infected individuals. A variable and often high proportion of individuals residing in areas where cutaneous leishmaniasis is endemic are exposed to Leishmania parasites, yet do not develop symptoms of disease. The role of this asymptomatic population in the transmission of disease is unknown and could interfere with the effectiveness of community or population-based control measures. Exposure to Leishmania is indirectly assessed by immunological tests; however, immunological evidence does not discriminate between historical exposure to the parasite and actual presence of parasites without causing clinical manifestations. We sought to determine whether viable Leishmania are present in individuals with immunological evidence of asymptomatic infection. Our results showed that at least 24% of individuals having immunological evidence of subclinical or asymptomatic infection harboured live Leishmania. These individuals may be at risk of activation of disease, or could represent an unperceived reservoir of parasites for vector-borne transmission. Characterization of Leishmania causing asymptomatic infection has not been possible due to technical limits of detection of parasites in low grade infections. We developed a molecular method that allows genotypic analysis of parasites involved in subclinical infection and potentially provides a means to assess their involvement in transmission.
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Affiliation(s)
| | - Rafael E. Gongora
- Centro Internacional de Entrenamiento e Investigaciones Médicas-CIDEIM, Cali, Colombia
| | - Liliana Valderrama
- Centro Internacional de Entrenamiento e Investigaciones Médicas-CIDEIM, Cali, Colombia
| | - Jimena Jojoa
- Centro Internacional de Entrenamiento e Investigaciones Médicas-CIDEIM, Cali, Colombia
| | - Neal Alexander
- Centro Internacional de Entrenamiento e Investigaciones Médicas-CIDEIM, Cali, Colombia
| | - Luisa C. Rubiano
- Centro Internacional de Entrenamiento e Investigaciones Médicas-CIDEIM, Cali, Colombia
| | - Alexandra Cossio
- Centro Internacional de Entrenamiento e Investigaciones Médicas-CIDEIM, Cali, Colombia
| | - Emily R. Adams
- Liverpool School of Tropical Medicine, Centre for Applied Health Research, Liverpool, United Kingdom
| | - Nancy G. Saravia
- Centro Internacional de Entrenamiento e Investigaciones Médicas-CIDEIM, Cali, Colombia
| | - María Adelaida Gomez
- Centro Internacional de Entrenamiento e Investigaciones Médicas-CIDEIM, Cali, Colombia
- * E-mail:
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de Paiva-Cavalcanti M, de Morais RCS, Pessoa-E-Silva R, Trajano-Silva LAM, Gonçalves-de-Albuquerque SDC, Tavares DDHC, Brelaz-de-Castro MCA, Silva RDFE, Pereira VRA. Leishmaniases diagnosis: an update on the use of immunological and molecular tools. Cell Biosci 2015; 5:31. [PMID: 26097678 PMCID: PMC4474361 DOI: 10.1186/s13578-015-0021-2] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2015] [Accepted: 06/05/2015] [Indexed: 11/10/2022] Open
Abstract
Leishmaniases are caused by obligate intracellular protozoan parasites of the genus Leishmania. They cause a spectrum of diseases, most notably visceral (VL), cutaneous (CL), and mucosal (ML) leishmaniasis, which affect millions of people around the world, each year. Despite scientific advances, leishmaniases cases are expanding, constituting an important public health problem. Immunological and molecular diagnostic tools have been increasingly applied for the early detection of these parasitic infections, since the existence of limitations in clinical and parasitological examinations may provide false results, thus interfering in epidemiological research and diseases control. Although there is a great diversity of available immunological assays, important common deficiencies persist, which explains the current exploration of the molecular biology in research fields, especially the Polymerase Chain Reaction (PCR) and its variants, such as real-time quantitative PCR. However, in the last years, significant results have also been reached inside of immunological context (especially by Flow Cytometry), for humans and dogs, demonstrated by research works of the New and Old worlds. In spite of their potential to clarify and minimize the present global situation of the diseases, the implementation of molecular or immunological innovative reference assays for VL and CL at health services is still a challenge due to several reasons, including lack of standardization among laboratories and structural concerns. In this article we bring classical and current information about technological advances for the immunological and molecular leishmaniases diagnosis, their features, and applications.
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Affiliation(s)
- Milena de Paiva-Cavalcanti
- Department of Immunology, Aggeu Magalhães Research Center, Oswaldo Cruz Foundation, Av. Prof. Moraes Rego s / n, 50670-420 Recife, PE Brazil
| | - Rayana Carla Silva de Morais
- Department of Immunology, Aggeu Magalhães Research Center, Oswaldo Cruz Foundation, Av. Prof. Moraes Rego s / n, 50670-420 Recife, PE Brazil
| | - Rômulo Pessoa-E-Silva
- Department of Immunology, Aggeu Magalhães Research Center, Oswaldo Cruz Foundation, Av. Prof. Moraes Rego s / n, 50670-420 Recife, PE Brazil
| | | | | | | | | | - Rafael de Freitas E Silva
- Department of Immunology, Aggeu Magalhães Research Center, Oswaldo Cruz Foundation, Av. Prof. Moraes Rego s / n, 50670-420 Recife, PE Brazil ; Department of Natural and Exact Sciences, University of Pernambuco (UPE), St. Capitão Pedro Rodrigues, 105, 55920-000 São José, Garanhuns, PE Brazil
| | - Valéria Rêgo Alves Pereira
- Department of Immunology, Aggeu Magalhães Research Center, Oswaldo Cruz Foundation, Av. Prof. Moraes Rego s / n, 50670-420 Recife, PE Brazil
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da Silva TAM, Gomes LI, Oliveira E, Coura-Vital W, Silva LDA, Pais FSM, Ker HG, Reis AB, Rabello A, Carneiro M. Genetic homogeneity among Leishmania (Leishmania) infantum isolates from dog and human samples in Belo Horizonte Metropolitan Area (BHMA), Minas Gerais, Brazil. Parasit Vectors 2015; 8:226. [PMID: 25889010 PMCID: PMC4407872 DOI: 10.1186/s13071-015-0837-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2015] [Accepted: 03/31/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Certain municipalities in the Belo Horizonte Metropolitan Area (BHMA), Minas Gerais, Brazil, have the highest human visceral leishmaniasis (VL) mortality rates in the country and also demonstrate high canine seropositivity. In Brazil, the etiologic agent of VL is Leishmania (Leishmania) infantum. The aim of this study was to evaluate the intraspecific genetic variability of parasites from humans and from dogs with different clinical forms of VL in five municipalities of BHMA using PCR-RFLP and two target genes: kinetoplast DNA (kDNA) and gp63. METHODS In total, 45 samples of DNA extracted from clinical samples (n = 35) or L. infantum culture (n = 10) were evaluated. These samples originated from three groups: adults (with or without Leishmania/HIV co-infection; n = 14), children (n = 18) and dogs (n = 13). The samples were amplified for the kDNA target using the MC1 and MC2 primers (447 bp), while the Sg1 and Sg2 (1330 bp) primers were used for the gp63 glycoprotein target gene. RESULTS The restriction enzyme patterns of all the samples tested were monomorphic. CONCLUSIONS These findings reveal a high degree of genetic homogeneity for the evaluated gene targets among L. infantum samples isolated from different hosts and representing different clinical forms of VL in the municipalities of BHMA studied.
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Affiliation(s)
- Thais Almeida Marques da Silva
- Laboratório de Pesquisas Clínicas, Centro de Pesquisas René Rachou, Fundação Oswaldo Cruz, Belo Horizonte, Minas Gerais, Brasil. .,Laboratório de Epidemiologia das Doenças Infecciosas e Parasitárias, Departamento de Parasitologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brasil.
| | - Luciana Inácia Gomes
- Laboratório de Pesquisas Clínicas, Centro de Pesquisas René Rachou, Fundação Oswaldo Cruz, Belo Horizonte, Minas Gerais, Brasil.
| | - Edward Oliveira
- Laboratório de Pesquisas Clínicas, Centro de Pesquisas René Rachou, Fundação Oswaldo Cruz, Belo Horizonte, Minas Gerais, Brasil.
| | - Wendel Coura-Vital
- Laboratório de Epidemiologia das Doenças Infecciosas e Parasitárias, Departamento de Parasitologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brasil. .,Pós-graduação em Ciências da Saúde: Infectologia e Medicina Tropical, Faculdade de Medicina, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brasil. .,Laboratório de Pesquisas Clínicas, Escola de Farmácia, Universidade Federal de Ouro Preto, Ouro Preto, Minas Gerais, Brasil.
| | - Letícia de Azevedo Silva
- Laboratório de Toxoplasmose, Departamento de Parasitologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brasil.
| | - Fabiano Sviatopolk-Mirsky Pais
- Grupo de Genômica e Biologia Computacional, Centro de Pesquisas René Rachou, Fundação Oswaldo Cruz, Belo Horizonte, Minas Gerais, Brasil.
| | - Henrique Gama Ker
- Laboratório de Pesquisas Clínicas, Escola de Farmácia, Universidade Federal de Ouro Preto, Ouro Preto, Minas Gerais, Brasil.
| | - Alexandre Barbosa Reis
- Laboratório de Pesquisas Clínicas, Escola de Farmácia, Universidade Federal de Ouro Preto, Ouro Preto, Minas Gerais, Brasil.
| | - Ana Rabello
- Laboratório de Pesquisas Clínicas, Centro de Pesquisas René Rachou, Fundação Oswaldo Cruz, Belo Horizonte, Minas Gerais, Brasil.
| | - Mariangela Carneiro
- Laboratório de Epidemiologia das Doenças Infecciosas e Parasitárias, Departamento de Parasitologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brasil. .,Pós-graduação em Ciências da Saúde: Infectologia e Medicina Tropical, Faculdade de Medicina, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brasil.
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Ceccarelli M, Galluzzi L, Sisti D, Bianchi B, Magnani M. Application of qPCR in conjunctival swab samples for the evaluation of canine leishmaniasis in borderline cases or disease relapse and correlation with clinical parameters. Parasit Vectors 2014; 7:460. [PMID: 25331737 PMCID: PMC4207623 DOI: 10.1186/s13071-014-0460-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2014] [Accepted: 09/26/2014] [Indexed: 12/03/2022] Open
Abstract
Background In leishmaniasis caused by Leishmania infantum, the dog acts as the main reservoir for the disease. Non-invasive sampling for Leishmania detection is pivotal for rapid and affordable diagnosis. Recently, the use of conjunctival swab (CS) has been evaluated as a non-invasive sampling technique for quantitative real-time PCR (qPCR). However, few investigations have been made on the applicability of CS qPCR in particular cases such as dogs with borderline IFAT titres, suspected disease relapse with comorbidity and therapy monitoring. The aims of this study were i) to confirm the efficacy of CS, comparing these samples to buffy coat (BC) samples, as effective non-invasive samples for Leishmania quantitative detection by qPCR and ii) to verify the usefulness of qPCR compared to conventional laboratory and clinical parameters to assist in therapeutic decision making regarding dogs with complex clinical cases. Methods Eighty dogs were divided into 4 groups based on their IFAT titres and clinical histories. Two qPCR assays were performed both on CS raw lysates and on purified DNA from BC samples. The assays were then compared. Z tests for difference of proportion, with Bonferroni correction, were carried out to evaluate the qPCR results. Logistic regression with backward stepwise elimination was performed to detect the subset of haematochemical variables significantly associated with PCR positivity. Results The qPCR performed on CS samples showed better sensitivity (87%) and specificity (96%) than assays carried out using BC samples, regardless of the primers used. The haematochemical parameters haemoglobin and globulins were found to be significantly associated with qPCR positivity. Pearson correlations between Leishmania kDNA load in CS and body condition scores or IFAT titres were calculated in dogs with new leishmaniasis diagnoses. The Leishmania kDNA load in CS correlated moderately with IFAT titres (R = 0.59) but a very weak correlation (R = 0.37) with body condition score (BCS) was found. Conclusions The applicability of CS for Leishmania detection in dogs was confirmed, revealing the usefulness of raw lysates for quantitative purposes. Moreover, the qPCR was found to be particularly useful in cases lacking a clear clinical diagnosis, where the haematochemical values cannot be predictive. Electronic supplementary material The online version of this article (doi:10.1186/s13071-014-0460-3) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Marcello Ceccarelli
- Department of Biomolecular Sciences, University of Urbino "Carlo Bo", via Saffi 2, 61029, Urbino, PU, Italy.
| | - Luca Galluzzi
- Department of Biomolecular Sciences, University of Urbino "Carlo Bo", via Saffi 2, 61029, Urbino, PU, Italy.
| | - Davide Sisti
- Department of Biomolecular Sciences, University of Urbino "Carlo Bo", via Saffi 2, 61029, Urbino, PU, Italy.
| | - Barbara Bianchi
- Veterinary Clinic "Santa Teresa", via Piave 23, 61032, Fano, PU, Italy.
| | - Mauro Magnani
- Department of Biomolecular Sciences, University of Urbino "Carlo Bo", via Saffi 2, 61029, Urbino, PU, Italy.
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Fukutani KF, Figueiredo V, Celes FS, Cristal JR, Barral A, Barral-Netto M, de Oliveira CI. Serological survey of Leishmania infection in blood donors in Salvador, Northeastern Brazil. BMC Infect Dis 2014; 14:422. [PMID: 25073468 PMCID: PMC4122787 DOI: 10.1186/1471-2334-14-422] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2014] [Accepted: 07/24/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Visceral Leishmaniasis is endemic to Brazil, where it is caused by Leishmania infantum (syn. Leishmania chagasi). Following parasite inoculation, individuals may experience asymptomatic infection, raising the possibility of parasite transmission through the transfusion of contaminated blood products. In the present work, we evaluated the prevalence of asymptomatic Leishmania infection among blood donors in Salvador, northeastern Brazil. METHODS Peripheral blood was collected from 700 blood donors attending the Blood Bank of Bahia (HEMOBA/SESAB), from January to September 2010. We evaluated anti-Leishmania serology by ELISA, employing Soluble Leishmania Antigen (sensitivity 90% and specificity 95%). The presence of parasite DNA was determined by qPCR, targeting a single copy gene (G6PD), and by end-point PCR, targeting multiple targets, namely a segment located in the Leishmania rRNA locus (ITS) and the conserved region of kinetoplastid DNA (kDNA) minicircles. RESULTS The blood-donor population was comprised of 74.5% of males with a mean age of 34 years. Anti-Leishmania serology by ELISA was positive in 5.4% (38/700) individuals. One individual was also positive for Chagas' disease and another tested positive for Syphilis. Employing qPCR, parasite DNA was not found in any of 38 seropositive samples. However, by ITS PCR, 8/38 (21%) samples were positive and this positivity increased to 26/38 (68%) when we targeted kDNA amplification. Agreement between both techniques (ITS and kDNA PCR) was fair (kappa = 0.219). CONCLUSIONS These results indicate that asymptomatic infection is present among the blood donor population of Salvador, a finding that warrants a broader discussion regarding the need to implement specific screening strategies.
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Affiliation(s)
| | | | | | | | | | | | - Camila I de Oliveira
- Centro de Pesquisas Gonçalo Moniz, Fundação Oswaldo Cruz (FIOCRUZ), Rua Waldemar Falcão, 121, Salvador, BA, Brazil.
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Solcà MDS, Bastos LA, Guedes CES, Bordoni M, Borja LS, Larangeira DF, da Silva Estrela Tuy PG, Amorim LDAF, Nascimento EG, de Sá Oliveira GG, dos-Santos WLC, Fraga DBM, Veras PST. Evaluating the accuracy of molecular diagnostic testing for canine visceral leishmaniasis using latent class analysis. PLoS One 2014; 9:e103635. [PMID: 25076494 PMCID: PMC4116254 DOI: 10.1371/journal.pone.0103635] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2014] [Accepted: 06/27/2014] [Indexed: 11/21/2022] Open
Abstract
Host tissues affected by Leishmania infantum have differing degrees of parasitism. Previously, the use of different biological tissues to detect L. infantum DNA in dogs has provided variable results. The present study was conducted to evaluate the accuracy of molecular diagnostic testing (qPCR) in dogs from an endemic area for canine visceral leishmaniasis (CVL) by determining which tissue type provided the highest rate of parasite DNA detection. Fifty-one symptomatic dogs were tested for CVL using serological, parasitological and molecular methods. Latent class analysis (LCA) was performed for accuracy evaluation of these methods. qPCR detected parasite DNA in 100% of these animals from at least one of the following tissues: splenic and bone marrow aspirates, lymph node and skin fragments, blood and conjunctival swabs. Using latent variable as gold standard, the qPCR achieved a sensitivity of 95.8% (CI 90.4–100) in splenic aspirate; 79.2% (CI 68–90.3) in lymph nodes; 77.3% (CI 64.5–90.1) in skin; 75% (CI 63.1–86.9) in blood; 50% (CI 30–70) in bone marrow; 37.5% (CI 24.2–50.8) in left-eye; and 29.2% (CI 16.7–41.6) in right-eye conjunctival swabs. The accuracy of qPCR using splenic aspirates was further evaluated in a random larger sample (n = 800), collected from dogs during a prevalence study. The specificity achieved by qPCR was 76.7% (CI 73.7–79.6) for splenic aspirates obtained from the greater sample. The sensitivity accomplished by this technique was 95% (CI 93.5–96.5) that was higher than those obtained for the other diagnostic tests and was similar to that observed in the smaller sampling study. This confirms that the splenic aspirate is the most effective type of tissue for detecting L. infantum infection. Additionally, we demonstrated that LCA could be used to generate a suitable gold standard for comparative CVL testing.
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Affiliation(s)
- Manuela da Silva Solcà
- Laboratório de Patologia e Biointervenção, Centro de Pesquisa Gonçalo Moniz–Fundação Oswaldo Cruz, Salvador, Bahia, Brazil
| | - Leila Andrade Bastos
- Laboratório de Patologia e Biointervenção, Centro de Pesquisa Gonçalo Moniz–Fundação Oswaldo Cruz, Salvador, Bahia, Brazil
| | - Carlos Eduardo Sampaio Guedes
- Laboratório de Patologia e Biointervenção, Centro de Pesquisa Gonçalo Moniz–Fundação Oswaldo Cruz, Salvador, Bahia, Brazil
| | - Marcelo Bordoni
- Laboratório de Patologia e Biointervenção, Centro de Pesquisa Gonçalo Moniz–Fundação Oswaldo Cruz, Salvador, Bahia, Brazil
| | - Lairton Souza Borja
- Laboratório de Patologia e Biointervenção, Centro de Pesquisa Gonçalo Moniz–Fundação Oswaldo Cruz, Salvador, Bahia, Brazil
| | - Daniela Farias Larangeira
- Laboratório de Patologia e Biointervenção, Centro de Pesquisa Gonçalo Moniz–Fundação Oswaldo Cruz, Salvador, Bahia, Brazil
- Escola de Medicina Veterinária, Universidade Federal da Bahia, Salvador, Bahia, Brazil
| | | | | | | | - Geraldo Gileno de Sá Oliveira
- Laboratório de Patologia e Biointervenção, Centro de Pesquisa Gonçalo Moniz–Fundação Oswaldo Cruz, Salvador, Bahia, Brazil
- Instituto Nacional de Ciência e Tecnologia em Doenças Tropicais (INCT - DT), Salvador, Bahia, Brazil
| | | | - Deborah Bittencourt Mothé Fraga
- Laboratório de Patologia e Biointervenção, Centro de Pesquisa Gonçalo Moniz–Fundação Oswaldo Cruz, Salvador, Bahia, Brazil
- Escola de Medicina Veterinária, Universidade Federal da Bahia, Salvador, Bahia, Brazil
- Instituto Nacional de Ciência e Tecnologia em Doenças Tropicais (INCT - DT), Salvador, Bahia, Brazil
| | - Patrícia Sampaio Tavares Veras
- Laboratório de Patologia e Biointervenção, Centro de Pesquisa Gonçalo Moniz–Fundação Oswaldo Cruz, Salvador, Bahia, Brazil
- Instituto Nacional de Ciência e Tecnologia em Doenças Tropicais (INCT - DT), Salvador, Bahia, Brazil
- * E-mail:
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Gannavaram S, Dey R, Avishek K, Selvapandiyan A, Salotra P, Nakhasi HL. Biomarkers of safety and immune protection for genetically modified live attenuated leishmania vaccines against visceral leishmaniasis - discovery and implications. Front Immunol 2014; 5:241. [PMID: 24904589 PMCID: PMC4033241 DOI: 10.3389/fimmu.2014.00241] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2014] [Accepted: 05/09/2014] [Indexed: 12/16/2022] Open
Abstract
Despite intense efforts there is no safe and efficacious vaccine against visceral leishmaniasis, which is fatal and endemic in many tropical countries. A major shortcoming in the vaccine development against blood-borne parasitic agents such as Leishmania is the inadequate predictive power of the early immune responses mounted in the host against the experimental vaccines. Often immune correlates derived from in-bred animal models do not yield immune markers of protection that can be readily extrapolated to humans. The limited efficacy of vaccines based on DNA, subunit, heat killed parasites has led to the realization that acquisition of durable immunity against the protozoan parasites requires a controlled infection with a live attenuated organism. Recent success of irradiated malaria parasites as a vaccine candidate further strengthens this approach to vaccination. We developed several gene deletion mutants in Leishmania donovani as potential live attenuated vaccines and reported extensively on the immunogenicity of LdCentrin1 deleted mutant in mice, hamsters, and dogs. Additional limited studies using genetically modified live attenuated Leishmania parasites as vaccine candidates have been reported. However, for the live attenuated parasite vaccines, the primary barrier against widespread use remains the absence of clear biomarkers associated with protection and safety. Recent studies in evaluation of vaccines, e.g., influenza and yellow fever vaccines, using systems biology tools demonstrated the power of such strategies in understanding the immunological mechanisms that underpin a protective phenotype. Applying similar tools in isolated human tissues such as PBMCs from healthy individuals infected with live attenuated parasites such as LdCen(-/-) in vitro followed by human microarray hybridization experiments will enable us to understand how early vaccine-induced gene expression profiles and the associated immune responses are coordinately regulated in normal individuals. In addition, comparative analysis of biomarkers in PBMCs from asymptomatic or healed visceral leishmaniasis individuals in response to vaccine candidates including live attenuated parasites may provide clues about determinants of protective immunity and be helpful in shaping the final Leishmania vaccine formulation in the clinical trials.
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Affiliation(s)
- Sreenivas Gannavaram
- Division of Emerging and Transfusion Transmitted Diseases, Center for Biologics Evaluation and Research, Food and Drug Administration , Bethesda, MD , USA
| | - Ranadhir Dey
- Division of Emerging and Transfusion Transmitted Diseases, Center for Biologics Evaluation and Research, Food and Drug Administration , Bethesda, MD , USA
| | - Kumar Avishek
- National Institute of Pathology, Indian Council of Medical Research , New Delhi , India
| | | | - Poonam Salotra
- National Institute of Pathology, Indian Council of Medical Research , New Delhi , India
| | - Hira L Nakhasi
- Division of Emerging and Transfusion Transmitted Diseases, Center for Biologics Evaluation and Research, Food and Drug Administration , Bethesda, MD , USA
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Mourão MVA, Toledo A, Gomes LI, Freire VV, Rabello A. Parasite load and risk factors for poor outcome among children with visceral leishmaniasis. A cohort study in Belo Horizonte, Brazil, 2010-2011. Mem Inst Oswaldo Cruz 2014; 109:147-53. [PMID: 24676657 PMCID: PMC4015258 DOI: 10.1590/0074-0276140257] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2013] [Accepted: 12/05/2013] [Indexed: 01/08/2023] Open
Abstract
Clinical and laboratory risk factors for death from visceral leishmaniasis (VL) are
relatively known, but quantitative real-time polymerase chain reaction (qPCR) might
assess the role of parasite load in determining clinical outcome. The aim of this
study was to identify risk factors, including parasite load in peripheral blood, for
VL poor outcome among children. This prospective cohort study evaluated children aged
≤ 12 years old with VL diagnosis at three times: pre-treatment (T0), during treatment
(T1) and post-treatment (T2). Forty-eight patients were included and 16 (33.3%) met
the criteria for poor outcome. Age ≤ 12 months [relative risk (RR) 3.51; 95%
confidence interval (CI) 1.89-6.52], tachydyspnoea (RR 3.46; 95% CI 2.19-5.47),
bacterial infection (RR 3.08; 95% CI 1.27-7.48), liver enlargement (RR 3.00; 95% CI
1.44-6.23) and low serum albumin (RR 7.00; 95% CI 1.80-27.24) were identified as risk
factors. qPCR was positive in all patients at T0 and the parasite DNA was
undetectable in 76.1% of them at T1 and in 90.7% at T2. There was no statistical
association between parasite load at T0 and poor outcome.
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Affiliation(s)
| | - Antonio Toledo
- Serviço Multiprofissional de Infectologia, Universidade José do Rosário Vellano-UNIFENAS, Belo Horizonte, MG, Brasil
| | - Luciana Inácia Gomes
- Laboratório de Pesquisas Clínicas, Centro de Pesquisas René Rachou-Fiocruz, Belo Horizonte, MG, Brasil
| | - Verônica Vieira Freire
- Laboratório de Pesquisas Clínicas, Centro de Pesquisas René Rachou-Fiocruz, Belo Horizonte, MG, Brasil
| | - Ana Rabello
- Laboratório de Pesquisas Clínicas, Centro de Pesquisas René Rachou-Fiocruz, Belo Horizonte, MG, Brasil
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Strong association between serological status and probability of progression to clinical visceral leishmaniasis in prospective cohort studies in India and Nepal. PLoS Negl Trop Dis 2014; 8:e2657. [PMID: 24466361 PMCID: PMC3900391 DOI: 10.1371/journal.pntd.0002657] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2013] [Accepted: 12/05/2013] [Indexed: 11/19/2022] Open
Abstract
INTRODUCTION Asymptomatic persons infected with the parasites causing visceral leishmaniasis (VL) usually outnumber clinically apparent cases by a ratio of 4-10 to 1. We assessed the risk of progression from infection to disease as a function of DAT and rK39 serological titers. METHODS We used available data on four cohorts from villages in India and Nepal that are highly endemic for Leishmania donovani. In each cohort two serosurveys had been conducted. Based on results of initial surveys, subjects were classified as seronegative, moderately seropositive or strongly seropositive using both DAT and rK39. Based on the combination of first and second survey results we identified seroconvertors for both markers. Seroconvertors were subdivided in high and low titer convertors. Subjects were followed up for at least one year following the second survey. Incident VL cases were recorded and verified. RESULTS We assessed a total of 32,529 enrolled subjects, for a total follow-up time of 72,169 person years. Altogether 235 incident VL cases were documented. The probability of progression to disease was strongly associated with initial serostatus and with seroconversion; this was particularly the case for those with high titers and most prominently among seroconvertors. For high titer DAT convertors the hazard ratio reached as high as 97.4 when compared to non-convertors. The strengths of the associations varied between cohorts and between markers but similar trends were observed between the four cohorts and the two markers. DISCUSSION There is a strongly increased risk of progressing to disease among DAT and/or rK39 seropositives with high titers. The options for prophylactic treatment for this group merit further investigation, as it could be of clinical benefit if it prevents progression to disease. Prophylactic treatment might also have a public health benefit if it can be corroborated that these asymptomatically infected individuals are infectious for sand flies.
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Courtenay O, Carson C, Calvo-Bado L, Garcez LM, Quinnell RJ. Heterogeneities in Leishmania infantum infection: using skin parasite burdens to identify highly infectious dogs. PLoS Negl Trop Dis 2014; 8:e2583. [PMID: 24416460 PMCID: PMC3886905 DOI: 10.1371/journal.pntd.0002583] [Citation(s) in RCA: 99] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2013] [Accepted: 10/29/2013] [Indexed: 11/18/2022] Open
Abstract
Background The relationships between heterogeneities in host infection and infectiousness (transmission to arthropod vectors) can provide important insights for disease management. Here, we quantify heterogeneities in Leishmania infantum parasite numbers in reservoir and non-reservoir host populations, and relate this to their infectiousness during natural infection. Tissue parasite number was evaluated as a potential surrogate marker of host transmission potential. Methods Parasite numbers were measured by qPCR in bone marrow and ear skin biopsies of 82 dogs and 34 crab-eating foxes collected during a longitudinal study in Amazon Brazil, for which previous data was available on infectiousness (by xenodiagnosis) and severity of infection. Results Parasite numbers were highly aggregated both between samples and between individuals. In dogs, total parasite abundance and relative numbers in ear skin compared to bone marrow increased with the duration and severity of infection. Infectiousness to the sandfly vector was associated with high parasite numbers; parasite number in skin was the best predictor of being infectious. Crab-eating foxes, which typically present asymptomatic infection and are non-infectious, had parasite numbers comparable to those of non-infectious dogs. Conclusions Skin parasite number provides an indirect marker of infectiousness, and could allow targeted control particularly of highly infectious dogs. Zoonotic visceral leishmaniasis is a sandfly-borne disease of humans and dogs caused by the intracellular parasite Leishmania infantum. Dogs are the proven reservoir. The disease is usually fatal unless treated, and is of global health significance. Diagnosis of canine infections relies on serum antibody-based tests that measure infection. In some endemic regions, a test-and-slaughter policy of seropositive dogs forms part of the national control policy to reduce human infection. However, this strategy is not considered effective. Since not all infected dogs are infectious to sandfly vectors, one option is to target control at infectious dogs, as only these dogs maintain transmission. We quantify Leishmania numbers in individual host tissues from time of infection using molecular methods. Comparing these results with their infectiousness to sandflies, we also evaluate the performance of molecular and immunological assays to identify infectious animals. Parasite numbers varied substantially between individuals, increasing with duration and severity of disease. Infectiousness to the sandfly vector was associated with high parasite numbers, and parasite loads in the skin was the best predictor of being infectious. The results suggest that molecular quantitation is useful in identifying individuals and populations responsible for maintaining transmission, with potential application in operational control programmes.
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Affiliation(s)
- Orin Courtenay
- School of Life Sciences, and Warwick Infectious Disease Epidemiology Research (WIDER), University of Warwick, Coventry, United Kingdom
- * E-mail:
| | - Connor Carson
- School of Life Sciences, and Warwick Infectious Disease Epidemiology Research (WIDER), University of Warwick, Coventry, United Kingdom
| | - Leo Calvo-Bado
- School of Life Sciences, and Warwick Infectious Disease Epidemiology Research (WIDER), University of Warwick, Coventry, United Kingdom
| | - Lourdes M. Garcez
- Laboratório de Epidemiologia e Imunologia aplicada às Leishmanioses, Seção de Parasitologia, Instituto Evandro Chagas, Belém, Pará, Brazil
- Centro do Ciências Biológicas e da Saúde, Universidade do Estado do Pará, Belém, Pará, Brazil
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Vallur AC, Duthie MS, Reinhart C, Tutterrow Y, Hamano S, Bhaskar KRH, Coler RN, Mondal D, Reed SG. Biomarkers for intracellular pathogens: establishing tools as vaccine and therapeutic endpoints for visceral leishmaniasis. Clin Microbiol Infect 2013; 20:O374-83. [PMID: 24237596 DOI: 10.1111/1469-0691.12421] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2013] [Revised: 09/20/2013] [Accepted: 09/30/2013] [Indexed: 11/30/2022]
Abstract
Visceral leishmaniasis in South Asia is a serious disease affecting children and adults. Acute visceral leishmaniasis develops in only a fraction of those infected individuals, the majority being asymptomatic with the potential to transmit infection and develop disease. We followed 56 individuals characterized as being asymptomatic by seropositivity with rk39 rapid diagnostic test in a hyperendemic district of Bangladesh to define the utility of Leishmania-specific antibodies and DNA in identifying infection. At baseline, 54 of the individuals were seropositive with one or more quantitative antibody assays and antibody levels persisted at follow up. Most seropositive individuals (47/54) tested positive by quantitative PCR at baseline, but only 16 tested positive at follow up. The discrepancies among the different tests may shed light on the dynamics of asymptomatic infections of Leishmania donovani, as well as underscore the need for standard diagnostic tools for active surveillance as well as assessing the effectiveness of prophylactic and therapeutic interventions.
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Affiliation(s)
- A C Vallur
- Infectious Disease Research Institute, Seattle, WA, USA
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Cota GF, de Sousa MR, de Freitas Nogueira BM, Gomes LI, Oliveira E, Assis TSM, de Mendonça ALP, Pinto BF, Saliba JW, Rabello A. Comparison of parasitological, serological, and molecular tests for visceral leishmaniasis in HIV-infected patients: a cross-sectional delayed-type study. Am J Trop Med Hyg 2013; 89:570-7. [PMID: 23836568 DOI: 10.4269/ajtmh.13-0239] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
The aim of this study was to evaluate the accuracy of invasive and non-invasive tests for diagnosis of visceral leishmaniasis (VL) in a large series of human immunodeficiency virus (HIV)-infected patients. In this delayed-type cross-sectional study, 113 HIV-infected symptomatic patients were evaluated by an adjudication committee after clinical follow-up to establish the presence or absence of VL as the target condition (reference test). The index tests were recombinant K39 antigen-based immunochromatographic test (rK39), indirect fluorescent antibody test (IFAT), prototype kit of direct agglutination test (DAT-LPC), and real-time polymerase chain reaction (qPCR) in peripheral blood. Compared with parasitological test and adjudication committee diagnosis or latent class model analyses, IFAT and rk39 dipstick test presented the lowest sensitivity. DAT-LPC exhibited good overall performance, and there was no statistical difference between DAT-LPC and qPCR diagnosis accuracy. Real-time PCR emerges as a less invasive alternative to parasitological examination for confirmation of cases not identified by DAT.
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Affiliation(s)
- Gláucia Fernandes Cota
- Eduardo de Menezes Hospital, Fundação Hospitalar do Estado de Minas Gerais (FHEMIG), Belo Horizonte, Minas Gerais, Brazil.
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