scholarly journals Emergent canine visceral leishmaniasis in Argentina: Comparative diagnostics and relevance to proliferation of human disease

2021 ◽  
Vol 15 (7) ◽  
pp. e0009552
Author(s):  
Kyoko Fujisawa ◽  
Charlotte Silcott-Niles ◽  
Poppy Simonson ◽  
Daniela Lamattina ◽  
Cristian A. Humeres ◽  
...  
Keyword(s):  
Visceral Leishmaniasis ◽  
Diagnostic Tests ◽  
Point Of Care ◽  
Clinical Status ◽  
Clinical Signs ◽  
Cross Reactivity ◽  
Buffy Coat ◽  
Mucocutaneous Leishmaniasis ◽  
Antibody Titres ◽  
Skin Samples

Background Visceral leishmaniasis (VL) is a zoonotic protozoal vector-borne disease that is a major public health challenge. In Argentina, canine (CVL) and human visceral leishmaniasis (HVL) have recently emerged. There is a lack of standardised diagnostic tests for CVL, which hinders control of CVL and HVL. Methodology/Principal findings Sampling was carried out in Puerto Iguazú, Argentina, comprising 190 asymptomatic, oligosymptomatic and polysymptomatic dogs. The following diagnostics were applied: microscopy of lymph node aspirate (LNA); three immunochromatographic rapid diagnostic tests (RDTs), prototype rK28-ICT, rK39-ICT (both Coris BioConcept), commercial rK39 (InBios); ELISA for IgG, IgG1 and IgG2, against rK28, rK39 or crude lysate antigen. DNA detection and analysis, with 30 dogs, was of the ITS1 region using skin samples, and loop-mediated isothermal amplification (LAMP; Eiken Loopamp) of buffy coat, skin scrape or LNA. 15.4% of dogs were positive by LNA microscopy. The rK28 RDT had higher seropositivity rate (61%) than either a prototype rK39 RDT (31.4%) or commercial rK39 RDT (18.8%), without cross-reactivity with six other pathogens. IgG anti-rK39 ELISA antibody titres, but not IgG2, were positively correlated with number of clinical signs. LAMP with LNA had a higher positivity rate than PCR; buffy coat sampling was more sensitive than skin scrape. ITS1 confirmed Leishmania (Leishmania) infantum as the agent of CVL. Leishmania (Viannia) spp. was detected in skin samples from two dogs, compatible with Leishmania (Viannia) braziliensis. Conclusions/Significance Seroprevalence confirmed rapid increase in CVL in Puerto Iguazú. The rK28 RDT test potentially has great value for improved point-of-care diagnosis. Given cost reduction and accessibility, commercial LAMP may be applicable to buffy coat. RDT biomarkers of CVL clinical status are required to combat spread of CVL and HVL. The presence of Viannia, perhaps as an agent of human mucocutaneous leishmaniasis (MCL), highlights the need for vigilance and surveillance.

scholarly journals OC 8173 RAPID DETECTION OF MYCOBACTERIUM ULCERANS BY RECOMBINASE POLYMERASE AMPLIFICATION

2019 ◽  
Vol 4 (Suppl 3) ◽  
pp. A2.1-A2
Author(s):  
Michael Frimpong ◽  
Hubert Ahor ◽  
Francisca Sarpong ◽  
Ken Laing ◽  
Mark Wansbrough-Jones ◽  
...  
Keyword(s):  
Sensitivity And Specificity ◽  
Point Of Care ◽  
Clinical Signs ◽  
Buruli Ulcer ◽  
Cross Reactivity ◽  
Current Control ◽  
Mycobacterium Ulcerans ◽  
Recombinase Polymerase Amplification ◽  
Clinical Samples ◽  
Clinical Sensitivity

BackgroundThere are no primary measures to prevent people from contracting Buruli ulcer, mainly due to poor understanding of its epidemiology. The current control strategy emphasises early diagnosis and prompt treatment, with the goal of avoiding the complications associated with advanced stages of the disease. There is no diagnostic test for the disease appropriate for use at the primary health care level where most cases are detected and treated. Diagnosis based on clinical signs is unreliable in inexperienced hands and complicated by infections that have similar presentations. This study was to develop and evaluate the use of recombinase polymerase amplification (RPA) assay for the detection of Mycobacterium ulcerans at the point of patient care.MethodsA specific fragment of IS2404 of M. ulcerans was amplified in 15 min at a constant temperature of 42°C, using the RPA assay and analysed on a portable fluorometre. The’method was tested for sensitivity and specificity with molecular standard of IS2404 DNA fragment, various M.’ulcerans strains, other mycobacteria and environmentally associated bacteria. Additionally, the assay performance as a diagnostic tool was tested with archived DNA from symptomatic patients. All results were compared with that of a highly sensitive IS2404 PCR.ResultsThe detection limit was 50 copies of IS2404 in 15 min using plasmid standard and 125 fg with genomic Mu DNA equivalent 25 genomic copies. The assay was highly specific in detecting all strains of M. ulcerans with no observed cross reactivity with other mycobacteria and common skin colonising bacteria. The clinical sensitivity and specificity of the BU-RPA assay using clinical samples was 86% and 100% respectively.ConclusionWe have developed a real-time isothermal RPA assay for the detection of M. ulcerans as a cheaper alternative to PCR. Combining this assay with a simple extraction protocol will maximise its use as point-of-care test for Buruli ulcer.

scholarly journals Comparison between available serologic tests for detecting antibodies againstAnaplasma phagocytophilumandBorrelia burgdorferiin horses in Canada

2015 ◽  
Vol 27 (4) ◽  
pp. 540-546 ◽  
Author(s):  
Gili Schvartz ◽  
Tasha Epp ◽  
Hilary J. Burgess ◽  
Neil B. Chilton ◽  
Katharina L. Lohmann
Keyword(s):  
Point Of Care ◽  
Fluorescent Antibody ◽  
Clinical Status ◽  
False Negative ◽  
Pairwise Comparison ◽  
Cross Reactivity ◽  
Multiplex Assay ◽  
Enzyme Linked Immunosorbent Assay ◽  
Serum Samples ◽  
Serologic Tests

To investigate the agreement between available serologic tests for the detection of antibodies against Anaplasma phagocytophilum and Borrelia burgdorferi, 50 serum samples from horses of unknown clinical status and at low risk for infection were tested. In addition to a point-of-care enzyme-linked immunosorbent assay (pocELISA), the evaluated tests included 2 indirect fluorescent antibody tests (IFATs) for antibodies against A. phagocytophilum and an IFAT, an ELISA confirmed with Western blot, and the Lyme multiplex assay for antibodies against B. burgdorferi. For each pair-wise comparison between serologic tests, the difference in the proportion of seropositive results as well as kappa and the prevalence-adjusted, bias-adjusted kappa were calculated. The proportion of seropositive results differed significantly in each pairwise comparison of tests for detection of antibodies against A. phagocytophilum, and between the pocELISA and IFAT as well as between the pocELISA and Lyme multiplex assay for detection of antibodies against B. burgdorferi. Agreement based on kappa varied from poor to fair while agreement was improved when evaluating prevalence-adjusted, bias-adjusted kappa. Lack of agreement may be explained by differences in methodology between the evaluated tests, cross-reactivity or false-positive and false-negative tests. In addition to the limitations of serologic test interpretation in the absence of clinical disease, this data suggest that screening of horses for exposure to tick-borne diseases in nonendemic areas may not be warranted.

Evaluation of rapid diagnostic tests and conventional enzyme-linked immunosorbent assays to determine prior dengue infection

2019 ◽  
Vol 26 (8) ◽  
Author(s):  
Matthew Bonaparte ◽  
Lingyi Zheng ◽  
Sanjay Garg ◽  
Bruno Guy ◽  
Yaniv Lustig ◽  
...  
Keyword(s):  
Diagnostic Tests ◽  
Point Of Care ◽  
Dengue Infection ◽  
Cross Reactivity ◽  
Rapid Diagnostic Tests ◽  
World Health ◽  
Serum Samples ◽  
West Nile ◽  
Immunosorbent Assays ◽  
Prevaccination Screening

Abstract Background In September 2018, the World Health Organization recommended that prevaccination screening be used with the tetravalent dengue vaccine (CYD-TDV), to ensure that only individuals with evidence of prior dengue infection (PDI) are vaccinated. Dengue rapid diagnostic tests (RDTs) would offer a potential solution for prevaccination screening at the point-of-care, but data on performance of available RDTs for identifying PDI are limited. We determined the suitability of four dengue RDTs and two conventional enzyme-linked immunosorbent assays (ELISAs) to identify PDI and evaluated cross-reactivity with co-circulating flaviviruses. Methods: Specificity was assessed using 534 dengue-negative [determined by 50% plaque reduction neutralization test (PRNT50)] serum samples from USA (n = 229) and dengue-endemic regions (n = 305). Sensitivity was assessed using 270 samples from recent (n = 90) or remote (n = 90) virologically confirmed prior dengue cases, and dengue PRNT50-positive samples (n = 90). Cross-reactivity was assessed in dengue-seronegative samples that were seropositive for yellow fever (n = 57), Japanese encephalitis (n = 37), West Nile (n = 59) or Zika (n = 41). Results: Dengue IgG RDTs and the Panbio ELISA exhibited favourable specificities (99–100%), higher than the Focus ELISA (95%). The RDTs had variable sensitivities (40–70%) that were lower than those of the ELISAs (≥90%). Cross-reactivity to other flaviviruses was low with RDTs (≤7%), but more significant with ELISAs (up to 51% for West Nile and 34% for Zika). No cross-reactivity to any of the four closely related flaviviruses was observed with the CTK Biotech RDT. For each SeroTest, sensitivity appeared similar in samples from individuals with recent (<13 months) vs remote (3–4 years) virologically confirmed PDI. Conclusions: In general, dengue IgG RDTs were found to be more specific and less cross-reactive than the ELISAs, but the latter were more sensitive for identifying PDI cases. Currently available RDTs could be temporizing tools for rapid and safe prevaccination screening until improved RDTs with increased sensitivity become available.

scholarly journals Leishmania ITS1 Is Genetically Divergent in Asymptomatic and Symptomatic Visceral Leishmaniasis: Results of a Study in Southern Iran

2020 ◽  
Vol 2020 ◽  
pp. 1-7
Author(s):  
Zahra Rezaei ◽  
Eqlima Azarang ◽  
Saeed Shahabi ◽  
Mostafa Omidian ◽  
Bahman Pourabbas ◽  
...  
Keyword(s):  
Visceral Leishmaniasis ◽  
Clinical Signs ◽  
Signs And Symptoms ◽  
Buffy Coat ◽  
Its1 Sequence ◽  
Crithidia Fasciculata ◽  
Southern Iran ◽  
Clinical Signs And Symptoms ◽  
Asymptomatic Individuals ◽  
Asymptomatic Case

It has been documented that the genotypic traits in symptomatic and asymptomatic cases of visceral leishmaniasis (VL) may be different. The current study aimed to find out and compare the genotype and intraspecies diversity of Leishmania Internal Transcribed Spacer 1 (ITS1) from asymptomatic and symptomatic VL cases in southern Iran. Methods. Buffy coat samples from seven VL patients, with clinical signs and symptoms, and seven asymptomatic VL cases, were evaluated in this study. Samples of asymptomatic individuals were obtained from children living in a VL endemic area in southern Iran, while the samples of symptomatic subjects were obtained from patients admitted to hospitals with a diagnosis of VL. DNA was extracted from the buffy coats of the samples and PCR-amplified, targeting the ITS1of Leishmania. The PCR products were sequenced, and the consensus sequences were assembled and multiple-aligned with a set of Leishmania strains retrieved from the GenBank, using Clustal W. The phylogenetic tree was rooted, using MEGAX software, and the diversities based on haplotype and nucleotides, as well as the number of polymorphic sites, were measured using DnaSP v5.0 software. The results of ITS1 sequencing in 5 out of 7 asymptomatic VL cases showed 99.25% to 100% similarity with the Leishmania infantum ITS1 sequence (accessed number: MN648746), and one isolate was considered as just Leishmania sp. In one sample, 99.75% similarity was seen with the ITS1 sequence of Crithidia fasciculata. Of the symptomatic VL patients, the PCR product revealed a 340 bp band corresponding to L. infantum in all of the samples. By analyzing the ITS1 sequences, all seven sequences formed a clade somewhat different from other Leishmania species and considered as Leishmania sp. Haplotype and nucleotide diversity were much more prevalent in symptomatic cases where six haplotypes were seen in the ITS1 of Leishmania from symptomatic patients and only two haplotypes were observed in the samples from asymptomatic cases. The findings of the current study showed that the Leishmania ITS1 from symptomatic VL and asymptomatic cases has significant genetic differences. Besides, infection with Crithidia fasciculata was reported, for the first time, in an asymptomatic case, which deserves further study.

scholarly journals Post-Study Point-of-Care Oral Fluid Testing in HIV-1 Vaccinees

2020 ◽  
Author(s):  
Karina Oganezova ◽  
Elvin J Fontana-Martinez ◽  
Jon A Gothing ◽  
Alisha Pandit ◽  
Esther Kwara ◽  
...  
Keyword(s):  
Diagnostic Tests ◽  
Oral Fluid ◽  
Point Of Care ◽  
Antibody Test ◽  
Cross Reactivity ◽  
Fourth Generation ◽  
Hiv Screening ◽  
Hiv Test ◽  
Hiv 1

Abstract Background Experimental HIV-1 vaccines frequently elicit antibodies against HIV-1 which may react with commonly used HIV diagnostic tests, a phenomenon known as vaccine-induced seropositivity/seroreactivity (VISP/VISR). We sought to determine under clinic conditions if a patient-controlled HIV test, OraQuick ADVANCE Rapid HIV-1/2 Antibody Test, detected HIV-1 vaccine-induced antibodies. Methods Plasma assessment of HIV-1 cross-reactivity was examined in end-of-study samples from 57 healthy, HIV-uninfected participants who received a candidate vaccine which has entered Phase 2B and 3 testing. We also screened 120 healthy, HIV-uninfected, unblinded HIV-1 vaccine participants with VISP/VISR for an assessment using saliva. These participants came from 21 different parent vaccine protocols representing 17 different vaccine regimens, all of which contained an HIV-1 envelope immunogen. OraQuick ADVANCE was compared to results from concurrent blood samples using a series of commercial HIV screening immunoassays. Results Fifty-seven unique participant plasma samples were assayed in vitro and only one (1.8%) was reactive by OraQuick ADVANCE. None of the 120 clinic participants (0%, [95% CI 0% to 3.7%]) tested positive by OraQuick ADVANCE and all were confirmed to be uninfected by HIV-1 viral RNA testing. 118 of the 120 (98.3%) participants had a reactive HIV test for VISP/VISR: 77 (64%) had at least one reactive fourth-generation HIV-1 diagnostic test (p<0.0001 vs no reactive OraQuick ADVANCE results) and 41 (34%) only had a reactive test by the less specific third-generation Abbott Prism assay. Conclusion These data suggest that this widely available patient-controlled test has limited reactivity to HIV-1 antibodies elicited by these candidate HIV-1 vaccines.

scholarly journals Early detection and persistent positivity of anti-Leishmania antibodies using a recombinant protein-based ELISA in naturally infected dogs in Brazil

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Matheus Silva de Jesus ◽  
João Victor Andrade Cruz ◽  
Lívia Brito Coelho ◽  
Lairton Souza Borja ◽  
Edmilson Domingos da Silva ◽  
...  
Keyword(s):  
Cohort Study ◽  
Visceral Leishmaniasis ◽  
Recombinant Protein ◽  
Diagnostic Test ◽  
Diagnostic Tests ◽  
Clinical Signs ◽  
Diagnostic Methods ◽  
Test Results ◽  
Time Points ◽  
Positive Results

Abstract Background Visceral leishmaniasis (VL) is a zoonotic disease caused by Leishmania infantum, for which dogs constitute the main urban parasite reservoir. Control measures and the treatment of canine visceral leishmaniasis (CVL) are essential to reduce VL cases. Early and accurate detection of L. infantum-infected dogs is crucial to the success of VL control. To improve the serological detection of L. infantum-exposed dogs, we evaluated the early diagnosis capacity of a recombinant protein (rLci5) in an immunosorbent assay (ELISA) to detect naturally infected dogs. Additionally, we evaluated the persistence of the positive results obtained by rLci5 ELISA in comparison to other conventional diagnostic test methods. Methods Serum samples obtained from 48 L. infantum-infected dogs involved in a cohort study were evaluated using different diagnostic methods (qPCR, EIE-LVC, DPP-LVC and splenic culture). The results were compared to rLci5 ELISA to determine its capacity to diagnose L. infantum infection at earlier infection time points. The persistence of positive diagnostic test results was also compared for each dog evaluated. Results rLci5 ELISA presented higher rates of positive results at early time points compared to the other diagnostic tests employed in the cohort study, as early as 24 months prior to detection by other tests. rLci5 ELISA positivity was 52.1% (25/48) at baseline, while qPCR was 35.4% (17/48), DPP-LVC 27.1% (13/48), EIE-LVC 22.9% (11/48) and culture only 4.2% (2/48). In at least one of the time points of the 24-month cohort study, rLci5 ELISA was positive in 100% (48/48) of the dogs, versus 83% (40/48) for qPCR, 75% (36/48) for DPP-LVC, 65% (31/48) for EIE-LVC and 31% (15/48) for culture. Investigating clinical signs in association with diagnostic test positivity, rLci5 ELISA successfully detected CVL in 62.9% (95/151) of the clinical evaluations with a score of 0–3, 64.3% (45/70) with scores between 4 and 7, and 73.7% (14/19) with scores > 7, providing higher rates of positivity than all other methods evaluated. Moreover, rLci5 ELISA presented the greatest persistence with respect to test positivity: 45.8% of the dogs evaluated. Conclusion Four diagnostic tests were compared to rLci5 ELISA, which presented earlier infection diagnosis and a greater persistence of positive test results. Accordingly, the use of the rLci5 ELISA can improve CVL diagnostic performance by detecting infected dogs sooner than other testing methods, with enhanced persistence of positive results over the course of the infection. Graphic abstract

scholarly journals An evaluation of the diagnostic performance characteristics of the Yellow Fever IgM immunochromatographic rapid diagnostic test kit from SD Biosensor in Ghana

PLoS ONE ◽  
2022 ◽  
Vol 17 (1) ◽  
pp. e0262312
Author(s):  
Lawrence Henry Ofosu-Appiah ◽  
Dodzi Kofi Amelor ◽  
Bright Ayensu ◽  
Ernest Akyereko ◽  
Nafisah Issah Rabiwu ◽  
...  
Keyword(s):  
Diagnostic Test ◽  
Rapid Diagnostic Test ◽  
Yellow Fever ◽  
Diagnostic Performance ◽  
Yellow Fever Virus ◽  
Point Of Care ◽  
Clinical Signs ◽  
Cross Reactivity ◽  
Performance Characteristics ◽  
Test Kit

Yellow fever is endemic in Ghana and outbreaks occur periodically. The prodromal signs due to Yellow Fever Virus (YFV) infection are non-specific, making clinical signs unreliable as the sole criteria for diagnosis. Accurate laboratory confirmation of suspected yellow fever cases is therefore vital in surveillance programs. Reporting of ELISA IgM testing results by laboratories can delay due to late arrival of samples from the collection sites as well as limited availability of ELISA kits. In this study, the diagnostic performance characteristics of a rapid immunochromatographic Standard Q Yellow Fever IgM test kit (SD Biosensor) was evaluated for the rapid diagnosis of Yellow Fever infection in Ghana. A panel of 275 sera, comprising 81 confirmed YFV positives and 194 negatives were re-tested in this study using the Standard Q Yellow Fever IgM test kit. Using the CDC/WHO Yellow Fever IgM capture ELISA as a benchmark, the sensitivity, specificity and accuracy of the Standard Q Yellow Fever test kit were 96.3%, 97.9% and 97.5%, respectively. The false positivity rate was 5.1% and there was no cross-reactivity when the Standard Q Yellow Fever test kit was tested against dengue, malaria and hepatitis B and C positive samples. In addition, inter-reader variability and invalid rate were both zero. The results indicate that the diagnostic performance of the Standard Q Yellow Fever IgM test kit on serum or plasma is comparable to the serum IgM detection by ELISA and can be used as a point of care rapid diagnostic test kit for YFV infection in endemic areas.

scholarly journals Comparison on the performance of Leishmania major-like and Leishmania braziliensis braziliensis as antigen for new world leishmaniasis IgG-immunofluorescence test

1991 ◽  
Vol 33 (6) ◽  
pp. 503-508 ◽  
Author(s):  
Maria Carolina Soares Guimarães ◽  
Beatriz J. Celeste ◽  
Edelma María Corrales L. ◽  
Carlos M.F. Antunes
Keyword(s):  
Visceral Leishmaniasis ◽  
Chagas Disease ◽  
Leishmania Major ◽  
Cross Reactivity ◽  
Leishmania Braziliensis ◽  
Nuclear Factor ◽  
Mucocutaneous Leishmaniasis ◽  
Immunofluorescent Test ◽  
Normal Controls ◽  
Better Than

The performance of an antigen of L. major-like promastigotes for the serological diagnosis of mucocutaneous leishmaniasis in the IgG-immunofluorescent test was compared to that of an antigen of L. braziliensis braziliensis. Each antigen was used to test two hundred and twenty-four sera of etiologies such as mucocutaneous leishmaniasis, deep mycoses, toxoplasmosis, malaria, Chagas' disease, visceral leishmaniasis, anti-nuclear factor, schistosomaiasis, rheumatoid factor and normal controls. Agreement between responses to each antigen was high: 77.2% of leishmaniases sera agreed on a positive or a negative result to both antigens and 91.1 % of control sera. Cross reactivity was restricted to Chagas' disease sera, visceral leishmaniasis, anti-nuclear factor and paracoccidiodomycosis. The quantitative response of leishmaniasis and Chagas' disease sera to both antigens was evaluated by a linear regression; although the y-intercept and the slope were different for each antigen, neither was better than the other in the disclosure of anti-Leishmania antibodies. In the case of Chagas' disease sera the L. major-like antigen was better than L. b. braziliensis' to disclose cross-reacting antibodies.

scholarly journals Detection of Immunoglobulin G1 Against rK39 Improves Monitoring of Treatment Outcomes in Visceral Leishmaniasis

2018 ◽  
Vol 69 (7) ◽  
pp. 1130-1135 ◽  
Author(s):  
Guy Mollett ◽  
Bruno C Bremer Hinckel ◽  
Tapan Bhattacharyya ◽  
Tegwen Marlais ◽  
Om Prakash Singh ◽  
...  
Keyword(s):  
Visceral Leishmaniasis ◽  
Treatment Outcomes ◽  
Strong Evidence ◽  
Diagnostic Tests ◽  
Leishmania Donovani ◽  
Clinical Status ◽  
Post Treatment ◽  
Serum Samples ◽  
Significant Difference ◽  
Early Case

Abstract Background Visceral leishmaniasis (VL), caused by the Leishmania donovani complex, is a fatal, neglected tropical disease that is targeted for elimination in India, Nepal, and Bangladesh. Improved diagnostic tests are required for early case detection and for monitoring the outcomes of treatments. Previous investigations using Leishmania lysate antigen demonstrated that the immunoglobulin (Ig) G1 response is a potential indicator of a patient’s clinical status after chemotherapy. Methods IgG1 or IgG enzyme-linked immunosorbent assays (ELISAs) with rK39 or lysate antigens and novel IgG1 rK39 rapid diagnostic tests (RDTs) were assessed with Indian VL serum samples from the following clinical groups: paired pre- and postchemotherapy (deemed cured); relapsed; other infectious diseases; and endemic, healthy controls. Results With paired pre- and post-treatment samples (n = 37 pairs), ELISAs with rK39- and IgG1-specific conjugates gave a far more discriminative decrease in post-treatment antibody responses when compared to IgG (P < .0001). Novel IgG1 rK39 RDTs provided strong evidence for decreased IgG1 responses in patients who had successful treatment (P < .0001). Furthermore, both IgG1 rK39 RDTs (n = 38) and ELISAs showed a highly significant difference in test outcomes between cured patients and those who relapsed (n = 23; P < .0001). RDTs were more sensitive than corresponding ELISAs. Conclusions We present strong evidence for the use of IgG1 in monitoring treatment outcomes in VL, and the first use of an IgG1-based RDT using the rK39 antigen for the discrimination of post-treatment cure versus relapse in VL. Such an RDT may have a significant role in monitoring patients and in targeted control and elimination of this devastating disease.

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