Reliability of non-lethal surveillance methods for detecting ranavirus infection
Ranaviruses have been identified as the etiologic agent in many amphibian die-offs across the globe. Polymerase chain reaction (PCR) is commonly used to detect ranavirus infection in amphibian hosts, but the test results may vary between tissue samples obtained by lethal and non-lethal procedures. Testing liver samples for infection is a common lethal sampling technique to estimate ranavirus prevalence because the pathogen often targets this organ and the liver is easy to identify and collect. However, tail clips or swabs may be more practicable for ranavirus surveillance programs compared with collecting and euthanizing animals, especially for uncommon species. Using PCR results from liver samples for comparison, we defined false-positive test results as occurrences when a non-lethal technique indicated positive but the liver sample was negative. Similarly, we defined false-negative test results as occurrences when a non-lethal technique was negative but the liver sample was positive. Using these decision rules, we estimated false-negative and false-positive rates for tail clips and swabs. Our study was conducted in a controlled facility using American bullfrog Lithobates catesbeianus tadpoles; false-positive and false-negative rates were estimated after different periods of time following exposure to ranavirus. False-negative and false-positive rates were 20 and 6%, respectively, for tail samples, and 22 and 12%, respectively, for swabs. False-negative rates were constant over time, but false-positive rates decreased with post-exposure duration. Our results suggest that non-lethal sampling techniques can be useful for ranavirus surveillance, although the prevalence of infection may be underestimated when compared to results obtained with liver samples.
- Supplementary Content
7
- 10.1111/tmi.13193
- Jan 8, 2019
- Tropical Medicine & International Health
To evaluate three non-invasive assays for the diagnosis of schistosomiasis mansoni in an Egyptian village. Urine was collected for the detection of circulating cathodic antigen (CCA) and cell-free parasite DNA (cfpd) by Point-of-contact (POC)-cassette assay and PCR, respectively. These tests were compared to Kato-Katz (KK) faecal thick smear for detection of Schistosoma mansoni eggs. Disease prevalence by POC-CCA assay was 86%; by PCR it was 39% vs. 27% by KK. Compared to KK, the sensitivity of POC-CCA reached 100%, but its specificity was only 19.2% with 41% accuracy. Sensitivity of the PCR assay for cfpd was 55.56%, and specificity was 67.12% with 64% accuracy. A new end point was calculated for combined analysis of KK, POC-CCA assay and PCR. Sensitivity for the three tests was 52.94%, 90.2% and 76.47%; specificity was 100% for KK and PCR and 18.37% for POC-CCA. The accuracy calculated for the three tests at the end point was 76% for KK, 55% for POC-CCA assay and 88% for PCR. Conventional PCR assay for detection of cfpd provides a potential screening tool for intestinal schistosomiasis with reliable specificity, reasonable accuracy and affordable financial and technical cost.
- Abstract
2
- 10.1016/j.ultrasmedbio.2011.05.732
- Jul 26, 2011
- Ultrasound in Medicine & Biology
The Diagnosis Performance of Ultrasonic Transient Elastography for Noninvasive Assessment of Liver Fibrosis in 1138 Chronic Hepatitis C Patients
- Research Article
17
- 10.1111/dmcn.13961
- Jul 7, 2018
- Developmental Medicine & Child Neurology
Infants born preterm are at risk of cerebral palsy (CP) and motor or cognitive developmental delay. For clinicians, it is essential to know the relative predictive accuracy of the most commonly used neuroimaging and neurophysiological tests for the early prediction of adverse neurodevelopmental outcome. The aim of this study was to compare the accuracy of these tests in survivors of a population of infants born very preterm. A retrospective cohort study was performed in 163 children born before 32 weeks gestational age. We compared the accuracy in predicting adverse neurodevelopmental outcome at the age of 2 years 6 months of early and late cranial ultrasound (CUS), magnetic resonance imaging, somatosensory evoked potentials after stimulation of the posterior tibial nerve, and electroencephalography by calculating positive and negative likelihood ratios. An abnormal early CUS is the best predictor of the presence of CP (positive likelihood ratio 6.09), motor developmental delay (positive likelihood ratio 3.11), and cognitive developmental delay (positive likelihood ratio 5.66). Overall, negative likelihood ratios were poor, ranging between 0.49 and 0.98, meaning that a normal test result had only minimal influence on the probability of adverse neurological outcome. None of the diagnostic tests had a good performance in predicting future neurodevelopmental problems in infants born preterm. A normal test result provided very little clinically useful information. An abnormal early cranial ultrasound (positive test result) is the best predictor of adverse neurodevelopmental outcome. All negative results have poor predictive value of future neurodevelopmental problems.
- Research Article
27
- 10.1186/gb-2002-3-9-preprint0007
- Jan 1, 2002
- Genome Biology
In the pharmaceutical industry and in academia substantial efforts are made to make the best use of the promising microarray technology. The data generated by microarrays are more complex than most other biological data attracting much attention at this point. A method for finding an optimal test statistic with which to rank genes with respect to differential expression is outlined and tested. At the heart of the method lies an estimate of the false negative and false positive rates. Both investing in false positives and missing true positives lead to a waste of resources. The procedure sets out to minimise these errors. For calculation of the false positive and negative rates a simulation procedure is invoked. The method outperforms commonly used alternatives when applied to simulated data modelled after real cDNA array data as well as when applied to real oligonucleotide array data. In both cases the method comes out as the over-all winner. The simulated data are analysed both exponentiated and on the original scale, thus providing evidence of the ability to cope with normal and lognormal distributions. In the case of the real life data it is shown that the proposed method will tend to push the differentially expressed genes higher up on a test statistic based ranking list than the competitors. The approach of making use of information concerning both the false positive and false negative rates in the inference adds a useful tool to the toolbox available to scientists in functional genomics.
- Research Article
2
- 10.3892/etm.2017.4610
- Jun 15, 2017
- Experimental and Therapeutic Medicine
We studied the factors related to infection after fixation in the process of bone late healed fracture and explored the factors that could predict the risk of postoperative infection. A total of 100 patients with open fractures of the tibia and fibula diagnosed in Zhengzhou No. 7 People's Hospital from 2007 to 2016 were enrolled in this study. Patients were subjected to staging surgery treatment. We divided them into the infection group (n=52) and the non-infection group (n=48) according to whether or not infection occurred after operation. Pearson correlation was used to analyze the relationship between postoperative infection and preoperative factors, and ROC curve was used to explore the factors which could predict the risk of postoperative infection. As a result, surgical timing and C-reactive protein were correlated with postoperative infection (P<0.05), and surgical timing was negatively correlated with postoperative infection. C-reactive protein was positively correlated with postoperative infection. Using 7 days as the cut-off point of surgical timing, false positive and false negative rates were 0 and 27.7%, respectively. Youden index value was 72.3%, and positive predictive and negative predictive values were 42.5 and 100%, respectively. With 54.55 mg/l as the cut-off point of C-reactive protein, the sensitivity and specificity of prediction were 88.2 and 94.1%, while the false negative and false positive rates were 11.8 and 5.9%, respectively. The Youden index value was 82.3%, and the positive predictive and negative predictive values were 75 and 96.7%, respectively. With 7 days as the cut-off point of surgical timing and 54.55 mg/l as the cutoff point of C-reactive protein at the same time, the positive predictive and negative predictive values were 88.2 and 97.6%, respectively. The false negative and false positive rates were 11.8 and 2.4%, respectively. The Youden index value was 85.8%. The positive predictive and negative predictive values were 88.2 and 97.6%, respectively. In conclusion, surgical timing and C-reactive protein were strongly correlated with postoperative infection and this correlation was not affected by age, sex or other inflammatory indexes. The incidence of postoperative infection was reduced when both factors were applied for the determination of surgery. In addition, incidence of complications will be reduced and the cure rate improved.
- Research Article
5
- 10.1016/j.ygyno.2020.11.001
- Nov 16, 2020
- Gynecologic Oncology
Accuracy of preoperative cross-sectional imaging in cervical cancer patients undergoing primary radical surgery
- Abstract
1
- 10.1016/j.ajog.2011.10.366
- Dec 28, 2011
- American Journal of Obstetrics and Gynecology
348: The accuracy of prenatal ultrasound in the diagnosis of true microcephaly
- Research Article
1
- 10.1525/elementa.2025.00020
- Sep 29, 2025
- Elem Sci Anth
Continuous monitoring (CM) solutions can facilitate faster detection and repair of emissions compared to traditional survey methods. This study tested 13 CM solutions over 12 weeks using single-blind controlled testing. Controlled release rates ranged from 0.08 to 6.75 kg CH4 h−1 and lasted 18 min to 8 h. Six solutions demonstrated 90% method detection limits (DL90s) ranging from 0.5 [0.3, 0.6] kg CH4 h−1 to 6.7 [5.9, 8.0] kg CH4 h−1. Of the 6 solutions, 5 had low False Positive (FP) rates (7.8%–18.9%), and 4 had low False Negative (FN) rates (8.0%–34.1%). Similar to Ilonze et al., the results show that the tested solutions balance method sensitivity with low FP and FN rates. All scanning/imaging solutions achieved high localization precision and accuracy (≥40%) at the equipment unit level. Single quantification estimates exhibited high relative quantification errors, ranging from 33 [0.9, 66]%, 95% confidence interval (CI) to 1326 [1003, 1648]%, 95% CI for small emissions (between 0.1 and 1 kg CH4 h−1) and from 3 [−20, 26]%, 95% CI to 3578 [−2832, 9988]%, 95% CI for large emissions (&gt;1 kg CH4 h−1). The mean detection time for all solutions ranged from 5 h to 5 days. Relative to previous studies, errors in quantification estimates decreased, as did FN and FP rates, with improved DL90s for 2 of the 4 retested solutions. However, the mean detection times increased for 2 solutions, remained constant for one solution, and decreased for 1 of the 4 retested solutions. These findings highlight that continuous, rigorous testing enhances solution performance, with notable improvements observed across multiple testing programs using the same test protocol.
- Research Article
1
- 10.1167/iovs.66.1.4
- Jan 2, 2025
- Investigative ophthalmology & visual science
When treating amblyopia, it is important to define when visual acuity (VA) is no longer improving (i.e., stable) because treatment decisions may be altered based on this determination. Simulated observed VAs, incorporating measurement error, were compared with simulated true VAs to determine false-positive and false-negative rates for stable VA for six rules (using single VA or test/retest measurements, with or without averaging, over two or three visits). Four HOTV VA profiles were modeled: stable or improving VA over time with each of patching and spectacles. Across six rules and two treatments, when true VA was stable, false-negative rates for stability ranged from 26% to 67%; when true VA was improving, false-positive rates for stability ranged from 0% to 38%. Single VA measurements at consecutive visits had a false-negative rate of 30% with patching and 29% with spectacles, a false-positive rate of 38% with patching and 35% with spectacles. Averaging two VA tests at each visit slightly increased the false-negative rate (35% with patching and 36% with spectacles), while reducing the false-positive rate (22% with patching and 21% with spectacles). Comparing false-negative and false-positive rates for stability across rules allows selection of the most appropriate rule for clinical practice or research. When considering less desirable treatments, a rule with a lower false-negative rate is preferable, whereas a rule with a lower false-positive rate would be preferred when it is important to correctly classify improving VA.
- Discussion
89
- 10.1097/jom.0000000000002138
- Jan 6, 2021
- Journal of Occupational & Environmental Medicine
False Positive Results With SARS-CoV-2 RT-PCR Tests and How to Evaluate a RT-PCR-Positive Test for the Possibility of a False Positive Result.
- Front Matter
5
- 10.1016/j.ajodo.2021.12.007
- Apr 23, 2022
- American Journal of Orthodontics and Dentofacial Orthopedics
Assessing the performance of diagnostic test accuracy measures
- Research Article
41
- 10.1016/j.ophtha.2017.08.002
- Aug 30, 2017
- Ophthalmology
The Effect of Testing Reliability on Visual Field Sensitivity in Normal Eyes: The Singapore Chinese Eye Study
- Addendum
2
- 10.1016/j.ijin.2025.11.002
- Nov 1, 2025
- International Journal of Intelligent Networks
RETRACTED: Dynamic Network Intrusion Detection Model Based on Transformer and Adversarial Autoencoder
- Research Article
7
- 10.1176/appi.ps.61.9.923
- Sep 1, 2010
- Psychiatric Services
Validation of Brief Screening Tools for Mental Disorders Among New Zealand Prisoners
- Research Article
- 10.1183/13993003/erj.42.suppl_57.p2894
- Sep 1, 2013
- European Respiratory Journal
The role of magnetic resonance imaging in staging of NSCLC