Chronic Wasting Disease Options of Surveillance in Carpathian Cervids: from the Identification of Characteristic Microscopic Pathologic Changes to Prionic Seeded Conversion and Amplification Assays

2001 ◽  
Vol 71 (3) ◽  
pp. 480-486
Author(s):  
Florica Barbuceanu ◽  
Stelian Baraitareanu ◽  
Stefania-Felicia Barbuceanu ◽  
Gabriel Predoi
Keyword(s):  
Enzyme Immunoassay ◽  
Diagnostic Tests ◽  
Chronic Wasting Disease ◽  
Rapid Diagnostic Tests ◽  
Diagnostic Methods ◽  
Wasting Disease ◽  
Western Immunoblotting ◽  
Negative Results ◽  
Antigen Capture ◽  
Confirmatory Tests

This paper describes the current diagnostic methods of Chronic Wasting Disease (CWD) in cervides used between 2013 and 2017 in Romania. The active surveillance of CWD involves the targeted groups screening by using rapid diagnostic tests (e.g., antigen capture enzyme immunoassay). If the first test does not provide certain negative results, then the confirmatory methods have been used, i.e. histopathology, immunohistochemistry and Western immunoblotting. These tests did not lead to the detection of CWD prions (PrPCWD) in Romania. This may be due to the absence or insufficient quantity of PrPCWD in samples, below the threshold of confirmatory tests.

scholarly journals Prozone-like phenomenon in travellers with fatal malaria: report of two cases

2015 ◽  
Vol 9 (03) ◽  
pp. 321-324 ◽  
Author(s):  
Lurdes Santos ◽  
Nuno Rocha Pereira ◽  
Paulo Andrade ◽  
Paulo Figueiredo Dias ◽  
Carlos Lima Alves ◽  
...  
Keyword(s):  
Diagnostic Tests ◽  
False Negative ◽  
Specific Antigen ◽  
Malaria Diagnosis ◽  
High Sensitivity ◽  
Rapid Diagnostic Tests ◽  
Microscopy Observation ◽  
Negative Results ◽  
False Negative Results ◽  
Potential Benefits

Malaria diagnosis remains a concern in non-endemic countries, with rapid diagnosis being crucial to improve patients’ outcome. Rapid diagnostic tests have high sensitivity but they also have flaws and false-negative results that might jeopardize malaria diagnosis. Some false-negative results might relate to a prozone-like effect. The authors describe two patients with false-negative rapid diagnostic tests in which a prozone-like effect might have been involved. The authors highlight that these tests should not be used without accompanying light microscopy observation of blood films and discuss potential benefits of using rapid diagnostic tests with more than one specific antigen for Plasmodium falciparum.

scholarly journals Chronic wasting disease (CWD) prion detection in blood from pre-symptomatic white-tailed deer harboring PRNP polymorphic variants

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Carlos Kramm ◽  
Paulina Soto ◽  
Tracy A. Nichols ◽  
Rodrigo Morales
Keyword(s):  
Protein Misfolding ◽  
Chronic Wasting Disease ◽  
Detection Efficiency ◽  
High Sensitivity ◽  
Diagnostic Methods ◽  
Tissue Type ◽  
Phase Detection ◽  
Wasting Disease ◽  
Clinical Phase ◽  
Additional Information

AbstractChronic wasting disease (CWD) is a prionopathy affecting wild and farmed cervids. This disease is endemic in North America and has been recently identified in Europe. Ante-mortem CWD tests of pre-clinical cervids may be an important tool in helping control the spread of this disease. Unfortunately, current CWD diagnostic methods are not suitable for non-tissue type samples. We reported that CWD prions can be detected in blood of pre-clinical CWD-infected white-tailed deer (WTD) with high sensitivity and specificity using the Protein Misfolding Cyclic Amplification (PMCA) assay. However, that report only included animals homozygous for codon 96G, the most common polymorphic version of the prion protein within this animal species. Here, we report CWD prion detection using blood of naturally infected WTD coding one or two copies of the PrP-96S polymorphic variant. Our results, from a blinded screening, show 100% specificity and ~ 58% sensitivity for animals harboring one 96S codon, regardless of their stage within the pre-clinical phase. Detection efficiency for PrP-96S homozygous animals was substantially lower, suggesting that this allele affect peripheral prion replication/tropism. These results provide additional information on the influence of codon 96 polymorphisms and the ability of PMCA to detect CWD in the blood of pre-clinical WTD.

Using of chemical sensors for rapid diagnostic tests of exhaled air

2019 ◽  
Vol 60 (12) ◽  
pp. 25-36
Author(s):  
Elena N. Maximova ◽  
◽  
Alyona E. Bezdetnova ◽  
Yury G. Shashmurin ◽  
Larisa N. Maskaeva ◽  
...  
Keyword(s):  
Chemical Sensors ◽  
Diagnostic Tests ◽  
Research Area ◽  
Medical Diagnostics ◽  
Rapid Diagnostic Tests ◽  
Diagnostic Methods ◽  
Early Disease Detection ◽  
Exhaled Air ◽  
Design Characteristics ◽  
Research On Application

The analysis of exhaled air on specific biomarkers content is one of the most promising and at the same time simplest methods of early disease detection. In the present paper the analysis of this issue has been performed on an example of diagnosis of some the most dangerous diseases, based on available literature. The relevance of research on application of new diagnostic methods, namely rapid diagnostic tests using chemical sensors, is shown in this work. The main disadvantages of modern medical diagnostics in comparison with advantages of solid-state chemical detectors application have been shown. General details about traditional methods of exhaled air analysis have been provided. The characteristic of chemical sensors and principle of their work was outlined. The main part of the literature review contains the results of the diseases diagnosis by analyzing expired air of people who suffer with diabetes mellitus, tuberculosis and cancer. Сhemical sensors or devices based on them, such as an electronic nose, served as control instruments. The review presents identifiable and potential biomarkers for these diseases. So as a rule, acetone vapour is selected as a biomarker of diabetes. At the same time, the choice of biomarkers for most of oncological diseases still remains a serious problem. Despite this, high results of analysis on the sensitivity and specificity of the used sensor devices to the diseases under consideration were noted in many cases compared with people in the control groups. Also the materials used for the manufacture of sensor elements and their design characteristics have been considered in the review. Doped metal oxides, quartz resonators covered with special coatings, nanomaterials based on gold particles and carbon nanotubes are most often used for the producing of sensor elements. The obtained research data indicate that the research area under consideration is promising, and widespread introduction of non-invasive express diagnostics in medical practice can be expected in the near future.

scholarly journals Point-of-Care Diagnostic Tests for Detecting SARS-CoV-2 Antibodies: A Systematic Review and Meta-Analysis of Real-World Data

2020 ◽  
Vol 9 (5) ◽  
pp. 1515 ◽  
Author(s):  
Matteo Riccò ◽  
Pietro Ferraro ◽  
Giovanni Gualerzi ◽  
Silvia Ranzieri ◽  
Brandon Michael Henry ◽  
...  
Keyword(s):  
Systematic Review ◽  
Diagnostic Tests ◽  
Large Scale ◽  
Point Of Care ◽  
Meta Analysis ◽  
Rapid Diagnostic Tests ◽  
Diagnostic Methods ◽  
Rt Pcr ◽  
Real World Data ◽  
Healthcare Facilities

SARS-CoV-2 is responsible for a highly contagious infection, known as COVID-19. SARS-CoV-2 was discovered in late December 2019 and, since then, has become a global pandemic. Timely and accurate COVID-19 laboratory testing is an essential step in the management of the COVID-19 outbreak. To date, assays based on the reverse-transcription polymerase chain reaction (RT-PCR) in respiratory samples are the gold standard for COVID-19 diagnosis. Unfortunately, RT-PCR has several practical limitations. Consequently, alternative diagnostic methods are urgently required, both for alleviating the pressure on laboratories and healthcare facilities and for expanding testing capacity to enable large-scale screening and ensure a timely therapeutic intervention. To date, few studies have been conducted concerning the potential utilization of rapid testing for COVID-19, with some conflicting results. Therefore, the present systematic review and meta-analysis was undertaken to explore the feasibility of rapid diagnostic tests in the management of the COVID-19 outbreak. Based on ten studies, we computed a pooled sensitivity of 64.8% (95%CI 54.5–74.0), and specificity of 98.0% (95%CI 95.8–99.0), with high heterogeneity and risk of reporting bias. We can conclude that: (1) rapid diagnostic tests for COVID-19 are necessary, but should be adequately sensitive and specific; (2) few studies have been carried out to date; (3) the studies included are characterized by low numbers and low sample power, and (4) in light of these results, the use of available tests is currently questionable for clinical purposes and cannot substitute other more reliable molecular tests, such as assays based on RT-PCR.

scholarly journals A Comparative Study of Diagnostic Methods of Malaria - Microscopy Versus Rapid Diagnostic Test Kits in a Tertiary Care Hospital, Rajasthan

2021 ◽  
Vol 8 (22) ◽  
pp. 1826-1830
Author(s):  
Saumya Singh ◽  
Neelam Chauhan ◽  
Jyoti Tomar ◽  
Aditya Pratap Singh
Keyword(s):  
Diagnostic Test ◽  
Peripheral Blood ◽  
Diagnostic Tests ◽  
Blood Smear ◽  
Peripheral Blood Smear ◽  
Rapid Diagnostic Tests ◽  
Diagnostic Methods ◽  
Test Method ◽  
Malarial Parasite ◽  
Card Test

BACKGROUND Malaria is one of the most prevalent parasitic diseases in the world including India. Majority of malarial cases are found in countries where cost-effectiveness, diagnostic test performance ease, and trained personnel, are the most important considerations. We wanted to compare the two methods of rapid diagnostic tests (RDTs) and microscopy in the diagnosis of malaria parasite infection. METHODS We studied 2,723 blood samples of patients who presented with signs and symptoms of malaria from out patient department (OPD) and various wards of Pacific Institute of Medical Science, Udaipur, Rajasthan, from Oct 2018 to Oct 2019. All samples obtained were first tested by RDTs and then the same samples were used to make peripheral blood film (PBF) for microscopy. RESULTS During the 1-year period, rapid card test method showed 178 positives for malarial parasite. Of these, 64 cases were positive for P. vivax and 108 cases for P. falciparum. Peripheral blood smear method showed 160 cases positive for malarial parasite. Of these, 55 cases were positive for P. vivax and 99 cases for P. falciparum and 6 cases of co-infection. PBF failed to detect 9 cases of P. vivax and 9 cases of P. falciparum which were positive by rapid card test. So, 18 cases reported PBF negative. Among these patients, there were 83 females and 95 males. Most affected age group was 16 – 30 years followed by 31 – 45 years. Maximum samples were from the month of October 19 with a positivity rate 35.4 %. CONCLUSIONS RDTs based on malaria antigen (whole blood) method is as specific and more sensitive than microscopy (which is being considered as the gold standard method). Peripheral blood smear method still remains superior for accurate species differentiation, quantitation of parasite and maintaining a permanent record. KEYWORDS Microscopy, Malaria, Rapid Diagnostic Tests

scholarly journals Modelling the epidemiology of malaria and spread of HRP2-negative Plasmodium falciparum following the replacement of HRP2-detecting rapid diagnostic tests

2022 ◽  
Vol 2 (1) ◽  
pp. e0000106
Author(s):  
Alisha Chaudhry ◽  
Jane Cunningham ◽  
Qin Cheng ◽  
Michelle L. Gatton
Keyword(s):  
Plasmodium Falciparum ◽  
Diagnostic Tests ◽  
False Negative ◽  
Parasite Prevalence ◽  
Rapid Diagnostic Tests ◽  
Negative Results ◽  
False Negative Results ◽  
Malaria Rapid Diagnostic Tests ◽  
The Impact

Malaria rapid diagnostic tests (RDTs) are dominated by products which use histidine-rich protein 2 (HRP2) to detect Plasmodium falciparum. The emergence of parasites lacking the pfhrp2 gene can lead to high rates of false-negative results amongst these RDTs. One solution to restore the ability to correctly diagnose falciparum malaria is to switch to an RDT which is not solely reliant on HRP2. This study used an agent-based stochastic simulation model to investigate the impact on prevalence and transmission caused by switching the type of RDT used once false-negative rates reached pre-defined thresholds within the treatment-seeking symptomatic population. The results show that low transmission settings were the first to reach the false-negative switch threshold, and that lower thresholds were typically associated with better long-term outcomes. Changing the diagnostic RDT away from a HRP2-only RDT is predicted to restore the ability to correctly diagnose symptomatic malaria infections, but often did not lead to the extinction of HRP2-negative parasites from the population which continued to circulate in low density infections, or return to the parasite prevalence and transmission levels seen prior to the introduction of the HRP2-negative parasite. In contrast, failure to move away from HRP2-only RDTs leads to near fixation of these parasites in the population, and the inability to correctly diagnose symptomatic cases. Overall, these results suggest pfhrp2-deleted parasites are likely to become a significant component of P. falciparum parasite populations, and that long-term strategies are needed for diagnosis and surveillance which do not rely solely on HRP2.

scholarly journals Comparative Evaluation of the Diagnostic Performance Characteristics of a One-Step Urine Malaria Test (UMT) against Rapid Diagnostic Tests (RDT) in Febrile Patients from Fako Division, Cameroon

2020 ◽  
Author(s):  
Nforbugwe Achu Che Awah ◽  
Rengerline Bihnwi Nchotu ◽  
Agnes Djema Bongah ◽  
Jules Clement Nguedia Assob
Keyword(s):  
Diagnostic Tests ◽  
Diagnostic Performance ◽  
Blood Smear ◽  
Limit Of Detection ◽  
Kidney Diseases ◽  
Rapid Diagnostic Tests ◽  
Diagnostic Methods ◽  
Performance Characteristics ◽  
Smear Microscopy ◽  
Malaria Test

Abstract Background : Presently, all malaria diagnostic methods like: microscopy and Rapid Diagnostic Tests (RDT) are invasive as they depend on blood samples for malaria diagnosis. Hence this study was aimed at comparing the diagnostic performance characteristics of the novel Urine Malaria Test (UMT) to the currently used Blood RDT, and to find out the efficacy of this UMT in detecting low parasitaemia in the study population. Methodology : A cross sectional study involving 200 febrile participants, with no signs and symptoms of rheumatoid arthritis and kidney diseases, no history of hematuria, >15/µl leucocytes and urobilinogens of > 1 mg/dl in their urine, were recruited from the month of April to August 2017 in the Limbe and Buea Regional Hospitals. The main samples requested for analyses were urine and blood. Results : Using the blood smear microscopy as standard, out of the 200 participants, 93 (46.5%) were positive for P . malaria. UMT had a sensitivity and specificity of 82.41% and 83.48 while that of RDT was 84.09% and 83.03 respectively falciparum (CI: 72.80 to 92.05%, Kappa 0.665, p =0.001). The UMT had a lowest limit of detection of 140 parasites/μl which was similar to RDT. The PPV and NPV of UMT and RDT were (81.74% and 85.98%) and (80.04% and 87.28%), respectively. There was a close agreement between the RDT and UMT when compared to microscopy (83.5% and 83.0% respectively). Conclusion : The UMT kit that was evaluated in comparison to the blood based RDT, showed a lot of similarities using the blood smear microscopy as gold standard. Hence, it can be recommended for the prompt and accurate diagnosis of malaria in febrile patients.

scholarly journals Cost-effectiveness analysis of malaria rapid diagnostic tests: a systematic review

2019 ◽  
Vol 8 (1) ◽  
Author(s):  
Xiao-Xiao Ling ◽  
Jia-Jie Jin ◽  
Guo-Ding Zhu ◽  
Wei-Ming Wang ◽  
Yuan-Yuan Cao ◽  
...  
Keyword(s):  
Cost Effectiveness ◽  
Diagnostic Tests ◽  
Economic Value ◽  
Health Economic Evaluation ◽  
Cost Effective ◽  
Rapid Diagnostic Tests ◽  
Diagnostic Methods ◽  
Cochrane Library ◽  
Economic Evaluations

Abstract Background Rapid diagnostic tests (RDT) can effectively manage malaria cases and reduce excess costs brought by misdiagnosis. However, few studies have evaluated the economic value of this technology. The purpose of this study is to systematically review the economic value of RDT in malaria diagnosis. Main text A detailed search strategy was developed to identify published economic evaluations that provide evidence regarding the cost-effectiveness of malaria RDT. Electronic databases including MEDLINE, EMBASE, Biosis Previews, Web of Science and Cochrane Library were searched from Jan 2007 to July 2018. Two researchers screened studies independently based on pre-specified inclusion and exclusion criteria. The Consolidated Health Economic Evaluation Reporting Standards (CHEERS) checklist was applied to evaluate the quality of the studies. Then cost and effectiveness data were extracted and summarized in a narrative way. Fifteen economic evaluations of RDT compared to other diagnostic methods were identified. The overall quality of studies varied greatly but most of them were scored to be of high or moderate quality. Ten of the fifteen studies reported that RDT was likely to be a cost-effective approach compared to its comparisons, but the results could be influenced by the alternatives, study perspectives, malaria prevalence, and the types of RDT. Conclusions Based on available evidence, RDT had the potential to be more cost-effective than either microscopy or presumptive diagnosis. Further research is also required to draw a more robust conclusion.

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