Performance of Detecting IgM Antibodies against Enterovirus 71 for Early Diagnosis

Enterovirus 71 (EV71) infection is more likely to induce severe complications and mortality than other enteroviruses. Methods for detection of IgM antibody against EV71 had been established for years, however, the performance of the methods in the very early diagnosis of EV71 infection had not been fully evaluated, which is especially meaningful because of the short incubation period of EV71 infection. In this report, the performance of an IgM anti-EV71 assay was evaluated using acute sera collected from 165 EV71 infected patients, 165 patients infected with other enteroviruses, and more than 2,000 sera from healthy children or children with other infected diseases. The results showed a 90% sensitivity in 20 patients who were in their first illness day, and similar sensitivity remained till 4 days after onset. After then the sensitivity increased to 95% to 100% for more than one month. The specificity of the assay in non-HFMD children is 99.1% (95% CI: 98.6–99.4), similar as the 99.9% specificity in healthy adults. The cross-reaction rate in patients infected with other non-EV71 enteroviruses was 11.4%. In conclusion, the data here presented show that the detection of IgM anti-EV71 by ELISA affords a reliable, convenient, and prompt diagnosis of EV71 infection

Development of an IgM-capture ELISA for Coxsackievirus A16 infection

National Key Technology Research and Development program of China [2008BAI70B00]; Science and Technology Plan Program of Xiamen City [3502Z20093010]; National Natural Science Foundation of China [30972826]Diagnosis of Coxsackievirus A16 (CA16) infection in China relies mainly on reverse transcription-polymerase chain reaction (RT-PCR) that require expensive equipment and special trained personnel, thus making its wide application in health care settings unlikely. In this study, a novel IgM anti-CA16 assay was developed for the detection of IgM antibodies to CA16 in serum. The responses and diagnostic value of IgM for the CA16 infection were:assessed by testing 1970 serum samples. The results showed that sensitivity of IgM test was 84.6% (259/306, 95% CI: 80.1-88.5), and specificity in control subjects and patients with CA16 HFMD was 99.2% (1508/1520, 95% CI: 98.6-99.6) and 90.3% (14/144, 95% CI: 84.2-94.6), respectively. The IgM positive rate reached 56.3% in the sera collected within the first day after onset, increased continuously to 95.3% at day 5 to day 7 after onset, and then reached 100% after more than 8 days. The cross-reaction rate in patients infected with other non-CA16 enteroviruses was 9.7% (14/144). These results suggest that the IgM anti-CA16 assay offers a rapid, convenient, and reliable method to detect acute CA16 infections. (C) 2010 Elsevier B.V. All rights reserved

Evaluation of a rapid test for detection of H5N1 avian influenza virus

The performance of H5 Dot ELISA, a rapid test for detection of avian H5N1 influenza virus, was evaluated using 30 H5N1 strains belonging to 10 major genetic groups of H5N1 influenza virus, 14 strains of non-H5N1 influenza virus and 652 field samples collected from healthy and diseased chickens from markets and poultry farms. The detection limit of the test for all 30 strains of H5N1 virus was <= 0.1 hemagglutinin (HA) units and the test yielded a negative result when tested against 100 HA units of the non-H5N1 viruses. The test gave a positive result for 87 of the 106 poultry samples from which H5N1 virus was isolated by culture and 3 of 546 culture-negative poultry samples. Compared with virus culture, the overall prediction rate of the test was determined to be 96.6%; the positive prediction rate was 96.7% and negative prediction rate, 96.6%. The false positive rate was 0.5% and false negative rate 17.9%. Considering that the test is also convenient to use, it was concluded that H5 Dot ELISA is suitable for field use in the investigation of H5N1 influenza outbreaks and surveillance in poultry. Crown Copyright (C) 2008 Published by Elsevier B.V. All rights reserved.Chinese National Project of Prevention and Treatment of Avian Influenza [2004BA519A73]; Chinese National Science and Technology Program [2006BA1011306]; Chinese National Natural and Science Foundation [30640017]; Science and Technology Project of Fujian Province in China [2005Y020, 2004YZ01-1]; Xiamen Science & Technology Program [3502Z20073001]; Research Fund for Control of Infectious Diseases of the Hong Kong Governmen

A Convenient Nucleic Acid Test on the Basis of the Capillary Convective PCR for the On-Site Detection of Enterovirus 71

National High Technology Research and Development Program 863 [2013AA020204]; Natural Science Foundation of Fujian Province [2013J06016]; National Natural Science Foundation of China [81371817]; National Major Scientific and Technological Special Project for Significant New Drugs Development [2011ZX09401-403]The recent and continuing epidemic of enterovirus 71 in China has affected millions of children and resulted in thousands of deaths. Timely diagnosis and management is essential for disease control. Current enterovirus 71 molecular tests require resources that are unavailable for on-site testing. We have developed a simple-to-operate nucleic acid test, the convenient and integrated nucleic acid test, for local medical institutions. It uses a convective PCR for rapid amplification, a dipstick for visual detection of PCR products, and a simple commercial kit for nucleic acid extraction. By using a specially designed reagent and reaction tube containing a dipstick, the amplification and detection processes are well integrated and simplified. Moreover, cross contamination that may be caused by an open-tube detection system can be avoided. On the basis of the convenient and integrated nucleic acid test, an enterovirus 71 assay for on-site testing was developed. After evaluating known hand, foot, and mouth disease virus stocks of 17 strains of 11 different serotypes, this assay showed a favorable detection spectrum and no cross-reactivity. Its clinical performance was established by testing 141 clinical samples and comparing the results with a nested RT-PCR method. The assay showed a clinical sensitivity and specificity of 98.5% and 100%, respectively. Our results suggest that this convenient and integrated nucleic acid test enterovirus 71 assay may serve as an on-site diagnosis tool

A rapid test for the detection of influenza A virus including pandemic influenza A/H1N1 2009

A new rapid diagnostic test for detection of influenza A virus was evaluated with four sets of experiments: first, a comparison with a commercial diagnostic kit against a panel of virus strains was conducted; second, the kit was tested against a collection of 40 strains of influenza A virus isolated from five different host species and 26 strains of other respiratory viruses used as controls; third, the kit was tested against specimens collected in the field obtained from human and chicken; and fourth, the kit was tested against the novel pandemic influenza A/H1N1 2009 clinical specimens obtained from admitted to hospital patients. The test kit displayed a sensitivity of 88% for both human specimens and avian specimens. The corresponding specificity was 99.3% for human specimens and 96.5% for avian specimens. This test kit may be useful for rapid diagnosis of influenza A virus. (C) 2010 Elsevier B.V. All rights reserved.National Natural Science Foundation of China [30901077]; Important National Science & Technology Specific Projects [2008ZX10004-006]; Project of Fujian Province [2008Y0059, 2009YZ0002

Specificity and cross-reactivity of IgM anti-EV71 in control subjects.

<p>Specificity and cross-reactivity of IgM anti-EV71 in control subjects.</p

List of primers designed for the specific amplification of EV71 and CA16.

<p>List of primers designed for the specific amplification of EV71 and CA16.</p

Sensitivity of IgM anti-EV71 test at Different Times After Symptomatic Onset.

<p>Sensitivity of IgM anti-EV71 test at Different Times After Symptomatic Onset.</p