scholarly journals Detection of West Nile Virus (WNV)-Specific Immunoglobulin M in a Reference Laboratory Setting during the 2002 WNV Season in the United States

2003 ◽  
Vol 10 (5) ◽  
pp. 764-768 ◽  
Author(s):  
Harry E. Prince ◽  
Wayne R. Hogrefe

ABSTRACT Between 1 June and 31 December 2002, 30,677 serum samples and 4,554 cerebrospinal fluid (CSF) samples were tested for West Nile virus (WNV)-specific immunoglobulin M (IgM) by an in-house enzyme-linked immunosorbent assay (ELISA); 1,481 serum samples (4.8%) and 345 CSF samples (7.6%) were positive for WNV IgM. Positive samples were forwarded to public health service laboratories (PHSLs) for further testing. PHSLs supplied results from their WNV IgM ELISAs for 654 samples; 633 (97%) were positive. PHSLs supplied WNV plaque reduction neutralization test results for 128 samples; 123 (96%) were positive. WNV IgM seroconversion and seroreversion trends were evaluated for 749 patients who each provided two serum samples that were tested during the study period. Of 574 patients whose first serum sample was IgM negative, 41 (7%) seroconverted (the second serum sample was IgM positive); of 175 patients whose first serum sample was IgM positive, 22 (13%) seroreverted (the second serum sample was IgM negative). The seroreversion rate was directly proportional to the time between serum sample collection; whereas only 1% of patients whose sera were collected <20 days apart showed seroreversion, 54% of patients whose sera were collected >60 days apart showed seroreversion. Conversion and reversion trends for CSF were evaluated for 68 patients. Of 54 patients whose first CSF specimen was IgM negative, 9 (17%) converted; none of 14 patients whose first CSF specimen was IgM positive reverted. Concomitant detection of WNV IgM in serum and CSF was assessed for 1,188 patients for whom paired serum and CSF specimens were available; for all 130 patients for whom IgM was detectable in CSF, IgM was also detectable in serum. These findings show that an in-house WNV IgM ELISA accurately identifies patients with WNV infection, document WNV IgM conversion and reversion trends, and demonstrate that WNV IgM detection in CSF is accompanied by WNV IgM detection in serum.

2003 ◽  
Vol 10 (1) ◽  
pp. 177-179 ◽  
Author(s):  
Harry E. Prince ◽  
Wayne R. Hogrefe

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.


2004 ◽  
Vol 11 (6) ◽  
pp. 1130-1133 ◽  
Author(s):  
Denise A. Martin ◽  
Amanda Noga ◽  
Olga Kosoy ◽  
Alison J. Johnson ◽  
Lyle R. Petersen ◽  
...  

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.


Tick-borne encephalitis virus (TBEV) was isolated for the first time in Sweden in 1958 (from ticks and from 1 tick-borne encephalitis [TBE] patient).1 In 2003, Haglund and colleagues reported the isolation and antigenic and genetic characterization of 14 TBEV strains from Swedish patients (samples collected 1991–1994).2 The first serum sample, from which TBEV was isolated, was obtained 2–10 days after onset of disease and found to be negative for anti-TBEV immunoglobulin M (IgM) by enzyme-linked immunosorbent assay (ELISA), whereas TBEV-specific IgM (and TBEV-specific immunoglobulin G/cerebrospinal fluid [IgG/CSF] activity) was demonstrated in later serum samples taken during the second phase of the disease.


2003 ◽  
Vol 10 (2) ◽  
pp. 317-322 ◽  
Author(s):  
Angel Balmaseda ◽  
María G. Guzmán ◽  
Samantha Hammond ◽  
Guillermo Robleto ◽  
Carolina Flores ◽  
...  

ABSTRACT To evaluate alternative approaches to the serological diagnosis of dengue virus (DEN) infection, the detection of DEN-specific immunoglobulin M (IgM) and IgA antibodies in serum and saliva specimens was assessed in 147 patients with symptoms of DEN infection seen at the Ministry of Health in Nicaragua. Seventy-two serum samples were determined to be positive for anti-DEN antibodies by IgM capture enzyme-linked immunosorbent assay, the routine diagnostic procedure. Serum and saliva specimens were obtained from 50 healthy adults as additional controls. IgM was detected in the saliva of 65 of the 72 serum IgM-positive cases, 6 of the 75 serum IgM-negative cases, and none of the control group, resulting in a sensitivity of 90.3% and a specificity of 92.0% and demonstrating that salivary IgM is a useful diagnostic marker for DEN infection. Detection of IgA in serum may be another feasible alternative for the diagnosis of DEN infection, with serum IgA found in 68 (94.4%) of the IgM-positive cases. In contrast, detection of IgA in saliva was not found to be a useful tool for DEN diagnosis in the present study. Further studies of the kinetics of antibody detection in another set of 151 paired acute- and convalescent-phase serum samples showed that DEN-specific IgA antibodies were detected in more acute-phase samples than were IgM antibodies. Thus, we conclude that DEN-specific IgA in serum is a potential diagnostic target. Furthermore, given that saliva is a readily obtainable, noninvasive specimen, detection of DEN-specific salivary IgM should be considered a useful, cheaper diagnostic modality with similar sensitivity and specificity to IgM detection in serum.


Animals ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 494
Author(s):  
Angela Petruccelli ◽  
Tiziana Zottola ◽  
Gianmarco Ferrara ◽  
Valentina Iovane ◽  
Cristina Di Russo ◽  
...  

Background: A retrospective sero-survey for evidence of West Nile virus (WNV) infection in European wild boar (Sus scorfa) was conducted in the Latium region, Italy, on stored serum samples of the period November 2011 to January 2012. Methods: Sera were collected from 168 European wild boars and screened for antibodies to WNV and other Flaviviruses by competitive enzyme linked immunosorbent assay (cELISA). All sera positive for Flavivirus antibodies by cELISA were further examined by virus neutralization test (VNT). To test the presence of Flavivirus RNA in samples, an RT-PCR was performed using a pan-Flavivirus primers pair. Results: Thirteen wild boars (7.73%) were seropositive for Flaviviruses. The hemolysis of serum samples limited the interpretation of the VNT for 7 samples, confirming the presence of specific antibody against WNV in a single European wild boar serum sample. The presence of ELISA positive/VNT negative samples suggests the occurrence of non-neutralizing antibodies against WNV or other antigen-related Flaviviruses. No samples resulted positive for Flavivirus by RT-PCR assay. Conclusion: Although a moderately high percentage of animals with specific antibody for WNV has been detected in wild boar in other surveillance studies in Europe, this has not been reported previously in Italy. Together, these data indicate that European wild boar are exposed to WNV and/or other related-Flavivirus in central Italy and confirm the usefulness of wild ungulates, as suitable Flavivirus sentinels.


Author(s):  
Matthew Finn

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.


2007 ◽  
Vol 81 (21) ◽  
pp. 11828-11839 ◽  
Author(s):  
Theodore Oliphant ◽  
Grant E. Nybakken ◽  
S. Kyle Austin ◽  
Qing Xu ◽  
Jonathan Bramson ◽  
...  

ABSTRACT Previous studies have established that an epitope on the lateral ridge of domain III (DIII-lr) of West Nile virus (WNV) envelope (E) protein is recognized by strongly neutralizing type-specific antibodies. In contrast, an epitope against the fusion loop in domain II (DII-fl) is recognized by flavivirus cross-reactive antibodies with less neutralizing potential. Using gain- and loss-of-function E proteins and wild-type and variant WNV reporter virus particles, we evaluated the expression pattern and activity of antibodies against the DIII-lr and DII-fl epitopes in mouse and human serum after WNV infection. In mice, immunoglobulin M (IgM) antibodies to the DIII-lr epitope were detected at low levels at day 6 after infection. However, compared to IgG responses against other epitopes in DI and DII, which were readily detected at day 8, the development of IgG against DIII-lr epitope was delayed and did not appear consistently until day 15. This late time point is notable since almost all death after WNV infection in mice occurs by day 12. Nonetheless, at later time points, DIII-lr antibodies accumulated and comprised a significant fraction of the DIII-specific IgG response. In sera from infected humans, DIII-lr antibodies were detected at low levels and did not correlate with clinical outcome. In contrast, antibodies to the DII-fl were detected in all human serum samples and encompassed a significant percentage of the anti-E protein response. Our experiments suggest that the highly neutralizing DIII-lr IgG antibodies have little significant role in primary infection and that the antibody response of humans may be skewed toward the induction of cross-reactive, less-neutralizing antibodies.


Author(s):  
Hasna Kunhipurayil ◽  
Muna Ahmed ◽  
Gheyath Nasrallah

Background: West Nile virus (WNV) is one of the most widely spread arboviruses worldwide and a highly significant pathogen in humans and animals. Despite frequent outbreaks and endemic transmission being reported in the Middle East and North Africa (MENA), seroprevalence studies of WNV in Qatar are highly lacking. Aim: This study aims to investigate the actual prevalence of WNV among local and expatriate communities in the Qatar using a large sample size of seemingly healthy donors. Method: A total of 1992 serum samples were collected from donors of age 18 or older and were tested for the presence of WNV antibodies. Serion enzyme-linked immunosorbent assay (ELISA) commercial microplate kits were used to detect the presence of the WNV IgM and IgG. The seropositivity was statistically analyzed using SPSS software with a confidence interval of 95%. Results: The seroprevalence of anti-WNV IgG and IgM in Qatar was 10.3% and 3.4%, respectively. The country-specific seroprevalence according to nationality for WNV IgG and IgM, respectively, were Sudan (37.0%, 10.0%), Egypt (31.6%, 4.4%), India (13.4%, 3.2%), Yemen(10.2%, 7.0%), Pakistan (8.6%, 2.7%), Iran (10.6%, 0.0%), Philippines (5.4%, 0.0%), Jordan(6.8%, 1.1%), Syria (2.6%, 9.6%), Palestine (2.6%, 0.6%), Qatar (1.6%, 1.7%), and Lebanon (0.9%, 0.0%). The prevalence of both IgM and IgG was significantly correlated with the nationality (p≤0.001). Conclusion: Among these tested nationalities, Qatar national has a relatively low burden of WNV disease. The highest prevalence of WNV was found in the Sub Saharan African nationalities like Sudan and Egypt. The seroprevalence of WNV is different from the previously reported arboviruses such as CHIKV and DENV, which was highest among Asian countries (India and Philippines). Further confirmatory tests such as viral neutralization assays are needed to confirm the IgM seropositivity in these samples since these samples could be a source of viral transmission through blood donation.


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