scholarly journals Evaluation of a Diagnostic Algorithm Using Immunoglobulin M Enzyme-Linked Immunosorbent Assay To Differentiate Human West Nile Virus and St. Louis Encephalitis Virus Infections during the 2002 West Nile Virus Epidemic in the United States

2004 ◽  
Vol 11 (6) ◽  
pp. 1130-1133 ◽  
Author(s):  
Denise A. Martin ◽  
Amanda Noga ◽  
Olga Kosoy ◽  
Alison J. Johnson ◽  
Lyle R. Petersen ◽  
...  
Keyword(s):  
United States ◽  
West Nile Virus ◽  
Immunosorbent Assay ◽  
Diagnostic Algorithm ◽  
The United States ◽  
Encephalitis Virus ◽  
Immunoglobulin M ◽  
Enzyme Linked Immunosorbent Assay ◽  
Virus Infections ◽  
West Nile

ABSTRACT A diagnostic algorithm was developed to differentiate between human infections of West Nile virus (WNV) and St. Louis encephalitis virus (SLEV) using positive-to-negative (P/N) ratios derived from the immunoglobulin M capture enzyme-linked immunosorbent assay (MAC-ELISA). To validate this algorithm, we tested 1,418 serum and cerebrospinal fluid (CSF) samples from confirmed WNV and SLEV infections collected during the WNV epidemic of 2002 in the United States. WNV P/N-to-SLEV P/N ratios (W/S ratios) were calculated and used to identify the infecting virus. These results were compared to results from the plaque reduction neutralization test (PRNT), which is currently the standard assay used to discriminate between closely related flavivirus infections. If the W/S ratio was ≥1, the predictive value positive (PNP) for WNV was 97.8%, where 95% of flavivirus cases were due to WNV infection and only 3.7% of specimens would require PRNT to differentiate WNV from SLEV infection. Use of the W/S ratio as part of the testing algorithm to interpret MAC-ELISA results generates reportable probable cases quickly, alleviating the need for PRNT in most instances.

scholarly journals Performance Characteristics of an In-House Assay System Used To Detect West Nile Virus (WNV)-Specific Immunoglobulin M during the 2001 WNV Season in the United States

2003 ◽  
Vol 10 (1) ◽  
pp. 177-179 ◽  
Author(s):  
Harry E. Prince ◽  
Wayne R. Hogrefe
Keyword(s):  
West Nile Virus ◽  
The United States ◽  
Immunoglobulin M ◽  
Enzyme Linked Immunosorbent Assay ◽  
Screening Assay ◽  
West Nile ◽  
Elisa System ◽  
Igm Elisa ◽  
Specific Immunoglobulin ◽  
Control And Prevention

ABSTRACT During the 2001 U. S. West Nile virus (WNV) season, 163 specimens were reactive in an in-house WNV-specific immunoglobulin M (IgM) screening enzyme-linked immunosorbent assay (ELISA) and were referred to either the Centers for Disease Control and Prevention or the appropriate state public health laboratory (CDC/SPHL) for additional testing. CDC/SPHL supplied results for 124 specimens that could be further evaluated in-house: 70 specimens were nonreactive in the CDC/SPHL WNV-specific IgM screening assay, and 54 specimens were reactive. These specimens were used to evaluate a modified in-house WNV-specific IgM ELISA that incorporated background subtraction to identify nonspecific reactivity and thus improve assay specificity. Of the 70 CDC/SPHL nonreactive samples, 49 (70%) were nonreactive in the modified ELISA; of the 54 CDC/SPHL reactive samples, 51 (94%) were reactive in the modified ELISA. Confirmatory studies performed by CDC/SPHL indicated that 38 CDC/SPHL screen-reactive specimens represented true WNV infection; all 38 specimens were reactive in the modified in-house WNV-specific IgM ELISA. These findings demonstrate that an in-house ELISA system for WNV-specific IgM effectively identifies patients with WNV infection.

scholarly journals Immunoglobulin G Avidity in Differentiation between Early and Late Antibody Responses to West Nile Virus

2006 ◽  
Vol 13 (1) ◽  
pp. 33-36 ◽  
Author(s):  
Janet L. Fox ◽  
Stuart L. Hazell ◽  
Leslie H. Tobler ◽  
Michael P. Busch
Keyword(s):  
United States ◽  
New York ◽  
West Nile Virus ◽  
The United States ◽  
Immunoglobulin M ◽  
West Nile ◽  
Marked Rise ◽  
Igm Antibodies ◽  
Igg Avidity ◽  
Igg Level

ABSTRACT In 1999 West Nile virus (WNV) surfaced in the United States in the city of New York and spread over successive summers to most of the continental United States, Canada, and Mexico. Because WNV immunoglobulin M (IgM) antibodies have been shown to persist for up to 1 year, residents in areas of endemicity can have persistent WNV IgM antibodies that are unrelated to a current illness with which they present. We present data on the use of IgG avidity testing for the resolution of conflicting data arising from the testing of serum or plasma for antibodies to WNV. Thirteen seroconversion panels, each consisting of a minimum of four samples, were used. All samples were tested for the presence of WNV IgM and IgG antibodies, and the avidity index for the WNV IgG-positive samples was calculated. Panels that exhibited a rise in the WNV IgM level followed by a sequential rise in the WNV IgG level were designated “primary.” Panels that exhibited a marked rise in the WNV IgG level followed by a sequential weak WNV IgM response and that had serological evidence of a prior flavivirus infection were designated “secondary.” All samples from the “primary” panels exhibited low avidity indices (less than 40%) for the first 20 to 30 days after the recovery of the index sample (the sample found to be virus positive). All of the “secondary” samples had elevated WNV IgG levels with avidity indices of ≥55%, regardless of the number of days since the recovery of the index sample. These data demonstrate that it is possible to differentiate between recent and past exposure to WNV or another flavivirus through the measurement of WNV IgG avidity indices.

scholarly journals Evaluation of a New Commercially Available Immunoglobulin M Capture Enzyme-Linked Immunosorbent Assay for Diagnosis of Japanese Encephalitis Infections

1999 ◽  
Vol 37 (11) ◽  
pp. 3738-3741 ◽  
Author(s):  
Andrea J. Cuzzubbo ◽  
Timothy P. Endy ◽  
David W. Vaughn ◽  
Tom Solomon ◽  
Ananda Nisalak ◽  
...  
Keyword(s):  
Cerebrospinal Fluid ◽  
Dengue Virus ◽  
Japanese Encephalitis Virus ◽  
Japanese Encephalitis ◽  
Immunosorbent Assay ◽  
Encephalitis Virus ◽  
Immunoglobulin M ◽  
Enzyme Linked Immunosorbent Assay ◽  
Virus Infections ◽  
Commercial Enzyme

A new commercial enzyme-linked immunosorbent assay (ELISA) for the diagnosis of Japanese encephalitis virus infections showed a sensitivity of 88% with sera and 81% with cerebrospinal fluid and a specificity of 97% with sera from patients with primary and secondary dengue virus infections. Specificity was 100% when samples from nonflavivirus infections were tested.

scholarly journals Evaluation of an Epitope-Blocking Enzyme-Linked Immunosorbent Assay for the Diagnosis of West Nile Virus Infections in Humans

2009 ◽  
Vol 16 (5) ◽  
pp. 749-755 ◽  
Author(s):  
M. A. Loroño-Pino ◽  
J. A. Farfan-Ale ◽  
B. J. Blitvich ◽  
J. L. Beebe ◽  
R. G. Jarman ◽  
...  
Keyword(s):  
West Nile Virus ◽  
Dengue Virus ◽  
Immunosorbent Assay ◽  
False Positive ◽  
False Positive Rate ◽  
Enzyme Linked Immunosorbent Assay ◽  
Virus Infections ◽  
Characteristic Analysis ◽  
West Nile ◽  
Positive Rate

ABSTRACT An epitope-blocking enzyme-linked immunosorbent assay (b-ELISA) was evaluated for the diagnosis of West Nile virus (WNV) infections in humans. Sera from patients diagnosed with WNV infections from an outbreak in 2003 in Colorado and from patients diagnosed with dengue virus infections from Mexico and Thailand were tested with the b-ELISA. The b-ELISAs were performed using the WNV-specific monoclonal antibody (MAb) 3.1112G and the flavivirus-specific MAb 6B6C-1. Although the WNV-specific b-ELISA was effective in diagnosing WNV infections in humans from Colorado, it was not efficacious for diagnosing WNV infections in serum specimens from Mexico and Thailand. In serum specimens from patients from Colorado, the WNV b-ELISA and the WNV plaque reduction neutralization test showed an overall agreement of 91%. The sensitivity and specificity of the WNV b-ELISA were 89% and 92%, respectively, with a false-positive rate of 5%, based on receiver operating characteristic analysis. In contrast, false-positive rate results in specimens from the countries of Mexico and Thailand, where flaviviruses are endemic, were 79% and 80%, presumably due to the presence of antibodies resulting from previous dengue virus infections in Mexico and/or Japanese encephalitis virus infections or vaccination in Thailand. Thus, in regions where people have experienced previous or multiple flavivirus infections, the use of the b-ELISA for WNV diagnosis is contraindicated.

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