Immunoglobulin M-Capture Enzyme-Linked Immunosorbent Assay Testing of Cerebrospinal Fluid and Serum from Horses Exposed to West Nile Virus by Vaccination or Natural Infection

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.

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West Nile Virus

10.1093/med/9780199976805.003.0053 ◽

2016 ◽

Author(s):

Matthew Finn

Keyword(s):

West Nile Virus ◽

Rna Virus ◽

Immunoglobulin M ◽

Enzyme Linked Immunosorbent Assay ◽

Mosquito Vector ◽

West Nile ◽

Csf Analysis ◽

Neuroinvasive Disease ◽

Breeding Grounds ◽

Arboviral Disease

West Nile virus (WNV) is a single-stranded RNA virus of the Flavivirus family that is transmitted via a mosquito vector, typically causing fever and capable of causing meningoencephalitis. Although mortality is low, it can lead to debilitating neuroinvasive disease in some patients. WNV is a leading cause of domestically-acquired arboviral disease and most commonly occurs in late August and early September. Consider WNV in otherwise unexplained cases of meningitis or encephalitis. Initial testing should consist of cerebrospinal fluid (CSF) analysis and West Nile immunoglobulin M enzyme-linked immunosorbent assay in serum and/or CSF. WNV is a nationally notifiable disease. Prevention remains the key to controlling this disease. Reducing the breeding grounds of the Culex mosquito and using insect repellant to prevent bites are two important strategies.

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Persistence of Antibodies to West Nile Virus in Naturally Infected Rock Pigeons (Columba livia)

Clinical and Diagnostic Laboratory Immunology ◽

10.1128/cdli.12.5.665-667.2005 ◽

2005 ◽

Vol 12 (5) ◽

pp. 665-667 ◽

Cited By ~ 61

Author(s):

Samantha E. J. Gibbs ◽

Douglas M. Hoffman ◽

Lillian M. Stark ◽

Nicole L. Marlenee ◽

Bradley J. Blitvich ◽

...

Keyword(s):

West Nile Virus ◽

Immunosorbent Assay ◽

Neutralization Test ◽

Columba Livia ◽

Maternal Antibodies ◽

Enzyme Linked Immunosorbent Assay ◽

West Nile ◽

Entire Study ◽

Plaque Reduction Neutralization Test ◽

Antibody Persistence

ABSTRACT Wild caught rock pigeons (Columba livia) with antibodies to West Nile virus were monitored for 15 months to determine antibody persistence and compare results of three serologic techniques. Antibodies persisted for the entire study as detected by epitope-blocking enzyme-linked immunosorbent assay and plaque reduction neutralization test. Maternal antibodies in squabs derived from seropositive birds persisted for an average of 27 days.

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NS1 Protein Secretion during the Acute Phase of West Nile Virus Infection

Journal of Virology ◽

10.1128/jvi.79.22.13924-13933.2005 ◽

2005 ◽

Vol 79 (22) ◽

pp. 13924-13933 ◽

Cited By ~ 74

Author(s):

Joanne Macdonald ◽

Jessica Tonry ◽

Roy A. Hall ◽

Brent Williams ◽

Gustavo Palacios ◽

...

Keyword(s):

West Nile Virus ◽

Real Time ◽

Real Time Pcr ◽

Diagnostic Marker ◽

Nonstructural Protein ◽

Immunoglobulin M ◽

Enzyme Linked Immunosorbent Assay ◽

Ns1 Protein ◽

West Nile ◽

Time Period

ABSTRACT The West Nile virus (WNV) nonstructural protein NS1 is a protein of unknown function that is found within, associated with, and secreted from infected cells. We systematically investigated the kinetics of NS1 secretion in vitro and in vivo to determine the potential use of this protein as a diagnostic marker and to analyze NS1 secretion in relation to the infection cycle. A sensitive antigen capture enzyme-linked immunosorbent assay (ELISA) for detection of WNV NS1 (polyclonal-ACE) was developed, as well as a capture ELISA for the specific detection of NS1 multimers (4G4-ACE). The 4G4-ACE detected native NS1 antigens at high sensitivity, whereas the polyclonal-ACE had a higher specificity for recombinant forms of the protein. Applying these assays we found that only a small fraction of intracellular NS1 is secreted and that secretion of NS1 in tissue culture is delayed compared to the release of virus particles. In experimentally infected hamsters, NS1 was detected in the serum between days 3 and 8 postinfection, peaking on day 5, the day prior to the onset of clinical disease; immunoglobulin M (IgM) antibodies were detected at low levels on day 5 postinfection. Although real-time PCR gave the earliest indication of infection (day 1), the diagnostic performance of the 4G4-ACE was comparable to that of real-time PCR during the time period when NS1 was secreted. Moreover, the 4G4-ACE was found to be superior in performance to both the IgM and plaque assays during this time period, suggesting that NS1 is a viable early diagnostic marker of WNV infection.

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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

Clinical and Diagnostic Laboratory Immunology ◽

10.1128/cdli.10.1.177-179.2003 ◽

2003 ◽

Vol 10 (1) ◽

pp. 177-179 ◽

Cited By ~ 4

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.

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