[show abstract][hide abstract] ABSTRACT: To investigate the proportion of viral respiratory tract infections among acute undifferentiated fevers (AUFs) at primary health facilities in southern Vietnam during 2001-2005, patients with AUF not caused by malaria were enrolled at twelve primary health facilities and a clinic for malaria control program. Serum was collected on first presentation (t0) and after 3 weeks (t3) for serology. After exclusion of acute dengue infection, acute and convalescent serum samples from 606 patients were using enzyme-linked immunoassays to detect IgA, as well as IgM and IgG antibodies against common respiratory viruses. Paired sera showed the following infections: human parainfluenza virus (HPIV, 4.7%), influenza B virus (FLUBV, 2.2%), influenza A virus (FLUAV, 1.9%) and human respiratory syncytial virus (HRSV, 0.6%). There was no association between type of infection and age, sex or seasonality; some inter-annual differences were observed for influenza. Antibody prevalence, indicative of previous infections, was relatively low: HPV, 56.8%, FLUBV, 12.1%; FLUAV, 5.9% and HRSV, 6.8%.
The Southeast Asian journal of tropical medicine and public health 09/2010; 41(5):1116-26. · 0.61 Impact Factor
[show abstract][hide abstract] ABSTRACT: To investigate which recent infection could have caused the present dengue-like symptoms, in adult patients clinically fulfilling the WHO criteria for dengue, in which serologically were not confirmed for dengue virus infections.
Prospective study. During an outbreak of dengue (between May 1995 and May 1996) 118 consecutive adults (>13 years) suspected by the WHO 1997 case definition of DF or DHF were investigated. Patients were examined for history of illness, physical and laboratory findings consisting of full blood counts, prothrombin time (PT), activated partial thromboplastin time (aPTT), liver function (bilirubin, ASAT, ALAT), renal function (creatinine), and serological assays included dengue, hantavirus, chikungunya, R. typhi, R. tsutsugamuchi, rubella virus, influenza A virus, and leptospira.
In 58 of the total 118 patients, recent dengue virus infection was serologically confirmed. In 20 of the remaining 60 patients, we found serological evidence of another recent infection: hantavirus (5), chikungunya virus (2), R. typhi (5), R. tsutsugamuchi (2), rubella virus (3), influenza A virus (1), and leptospira (2). No evidence for recent infection with any of the mentioned agents was detected in the remaining 40 specimens.
We conclude that based on clinical characteristics alone, it is not easy to diagnose dengue. Specific laboratory tests to differentiate dengue from other febrile illnesses are needed. Among these, in Indonesia hantavirus infection should be considered as well.
[show abstract][hide abstract] ABSTRACT: Diagnosing dengue in febrile patients is challenging. Of a total of 459 patients with acute undifferentiated fever, randomly selected from 12 primary health facilities and 1 clinic of the provincial malaria station in southern Vietnam, dengue-specific antibody (Ab) and NS1Ag enzyme-linked immunosorbent assay (ELISA) (Platelia, Bio-Rad Laboratories, Hercules, CA 94547, US) were performed on acute (t0) and convalescent (t3 weeks) sera. Polymerase chain reaction (PCR) was used for confirmation. Based on a composite of the NS1Ag-ELISA, Ab-ELISA, and PCR results, 54 (12%) patients had acute dengue. Positive and negative predictive values were 65% and 98% for the Ab-based diagnosis and 91% and 92% for NS1Ag, respectively. The agreement between Ab- and NS1Ag-based diagnosis was poor (kappa value, 0.2). Two patients without dengue had detectable NS1Ag on t0 and t3, 1 just above the cutoff value and 1 with very high values. For 5 dengue patients, NS1Ag was still detectable at very high levels at t3. Dengue NS1Ag can be used for early diagnosis of dengue; infrequent false-positive results need further clarification.
[show abstract][hide abstract] ABSTRACT: The reproducibilty of dengue IgM and IgG ELISA was studied in serum and filter paper blood spots from Vietnamese febrile patients.
781 pairs of acute (t0) and convalescent sera, obtained after three weeks (t3) and 161 corresponding pairs of filter paper blood spots were tested with ELISA for dengue IgG and IgM. 74 serum pairs were tested again in another laboratory with similar methods, after a mean of 252 days.
Cases were classified as no dengue (10 %), past dengue (55%) acute primary (7%) or secondary (28%) dengue. Significant differences between the two laboratories' results were found leading to different diagnostic classification (kappa 0.46, p < 0.001). Filter paper results correlated poorly to serum values, being more variable and lower with a mean (95% CI) difference of 0.82 (0.36 to 1.28) for IgMt3, 0.94 (0.51 to 1.37) for IgGt0 and 0.26 (-0.20 to 0.71) for IgGt3. This also led to differences in diagnostic classification (kappa value 0.44, p < 0.001) The duration of storage of frozen serum and dried filter papers, sealed in nylon bags in an air-conditioned room, had no significant effect on the ELISA results.
Dengue virus IgG antibodies in serum and filter papers was not affected by duration of storage, but was subject to inter-laboratory variability. Dengue virus IgM antibodies measured in serum reconstituted from blood spots on filter papers were lower than in serum, in particular in the acute phase of disease. Therefore this method limits its value for diagnostic confirmation of individual patients with dengue virus infections. However the detection of dengue virus IgG antibodies eluted from filter paper can be used for sero-prevalence cross sectional studies.
[show abstract][hide abstract] ABSTRACT: To study in relapsing-remitting (RR) multiple sclerosis (MS) whether exacerbations and brain activity as measured by magnetic resonance imaging (MRI) are associated with plasma levels of anti-Epstein Barr (EBV) antibodies and EBV DNA.
This was a prospective study with 73 RR MS patients followed for an average of 1.7 years with frequent neurological examination and blood sampling. Antibodies to various EBV proteins were measured by ELISA and plasma EBV DNA was measured by PCR.
All MS patients had IgG antibodies to EBV (viral capsid antigen (VCA) and/or EBV nuclear antigen (EBNA)), irrespective whether samples were taken at stable disease or exacerbation. A significantly elevated percentage of the patients (48%) had antibodies against EBV antigens (early antigen, EA) that indicate active viral replication, compared with the age matched healthy controls (25%). Antibodies against a control herpesvirus, cytomegalovirus, were similar between the two groups. The percentage of EA positive individuals and EA titres did not differ between stable disease or exacerbation. Anti-VCA IgM was positive in three cases, unrelated to disease activity. Using a highly sensitive PCR on 51 samples taken at exacerbation visits, only three patients were found to have one timepoint with viraemia, and this viraemia was unrelated to disease activity. Of special note was the fact that anti-EA seropositive patients remained seropositive during follow up, with stable titres over time. We hypothesised that these patients may constitute a subgroup with higher disease activity, due to the triggering effect of a chronic attempt of the virus to reactivate. The EA positive group did not differ from the EA negative with respect to clinical disease activity or other characteristics. However, in the EA positive group, analysis with gadolinium enhanced MRI indicated more MRI disease activity.
There was no evidence for increased clinical disease activity in the subgroup of MS patients with serological signs of EBV reactivation. However, the observation that chronic EBV reactivation may be associated with increased inflammatory activity as assessed by gadolinium enhanced MRI lesions should be reproduced in a larger and independent dataset.
[show abstract][hide abstract] ABSTRACT: Dengue is highly endemic in southern Vietnam and all four serotypes of dengue virus have already been identified. To determine the age-specific prevalence of dengue and associated risk factors, we conducted a serological study at two primary schools and assessed risk factors by analysing children's questionnaires and household surveys. Sera were collected from 961 primary schoolchildren in Binh Thuan Province and tested for the presence of dengue virus serum antibodies using an indirect immunoglobulin G (IgG) enzyme-linked immunosorbent assay (ELISA). The antibody prevalence of the total population was 65.7% (n=631) which increased from 53.0 to 88.2% with age. The annual incidence of a first dengue infection, estimated by binary regression of the seroprevalence by age, was 11.7%. Interestingly, the prevalence of dengue IgG antibodies was significantly higher in children who confirmed using a pit latrine (RR 1.467, 95% CI: 1.245-1.730) and whose domestic environment contained discarded cans (RR 1.238, 95% CI: 1.042-1.470) and pigs (RR 1.228, 95% CI: 1.002-1.504). The epidemiology of dengue in southern Vietnam is stable with a constantly high annual incidence of first infections. Transmission occurs mainly peri-domestically, which has important public health implications.
Tropical Medicine & International Health 05/2005; 10(4):379-86. · 2.94 Impact Factor
[show abstract][hide abstract] ABSTRACT: Increased travelling to countries endemic for dengue fever (DF) demands efficient laboratory diagnostics. Nucleic acid amplification techniques (NAT) are now frequently used for rapid diagnosis of imported viral diseases. Different PCR systems are available.
In order to assess the quality of molecular diagnostics of dengue virus infections, an external quality assurance (EQA) in PCR diagnostics was conducted. Study design: A panel of 10 human plasma samples was prepared and spiked with dengue virus types DEN-1 to DEN-4. In addition, a 10-fold dilution series (1:10-1:10(4) ) of DEN-3 virus was included. The panel was pre-tested by nested RT-PCR, in-house real-time PCR, and a commercial real-time PCR kit. The samples were inactivated by gamma irradiation and shipped in freeze dried state. Thirteen laboratories, within the European network for the diagnostics of imported viral diseases (ENIVD) took part using either single-round, nested, or real-time RT-PCR methods. Two laboratories used two methods in parallel, summarising up to 15 comparable results.
33-100% correct results were achieved. All laboratories detected DEN-2 correctly, followed by DEN-1 (14 positive results of 15), DEN-3 (12/15) and DEN-4 (11/15). Testing of the serial dilution revealed low sensitivity in many labs, with results ranging from 33 to 80% of correctly tested samples.
The EQA gives a feedback of the quality of the RT-PCR system used by each respective laboratory. The different test systems and amplification conditions demonstrate the importance of external quality control measures.
Journal of Clinical Virology 09/2004; 30(4):291-6. · 3.29 Impact Factor
[show abstract][hide abstract] ABSTRACT: A multiplex reverse transcription (RT) polymerase chain reaction combined with a microwell hybridization assay (m-RT-PCR-ELISA) was previously developed to detect nine different microorganisms: enterovirus (EV), influenza virus type A (IVA) and type B (IVB), respiratory syncytial virus (RSV), parainfluenzavirus type 1 (PIV1) and type 3 (PIV3), adenovirus (AV), Mycoplasma pneumoniae (Mpn), Chlamydia pneumoniae (Cpn) in a single test. These organisms do not usually colonize the respiratory tract of humans, but, if present, it may be assumed they are involved in respiratory disease.
The m-RT-PCR-ELISA was tested on (i) culture supernatants of unknown contents, (ii) by determining the analytical sensitivity of 10-fold serial dilutions of culture supernatants and (iii) by determining clinical sensitivity in a retrospective study on 411 clinical specimens. The specimens were re-tested in parallel by m-RT-PCR-ELISA versus the gold standard culture and immunfluorescence, and versus individual RT-PCR.
(i) The 9-valent m-RT-PCR-ELISA shows 83% to 100% concordant results on 103 culture supernatants containing different organisms. (ii) The analytical sensitivity was as follows: higher sensitivity of the 9-valent m-RT-PCR-ELISA in comparison to culture in the cases of PIV3, IVA and IVB (factor 10) and AV and EV (factor 100), and lower sensitivity in case of RSV and PIV1 (factor 10). (iii) The agreement with the gold standard in the kappa statistic was excellent for RSV (kappa = 0.937), IVA (kappa = 0.940), very good for PIV1 (kappa = 0.914), IVB (kappa = 0.907) and satisfactory for PIV3 (kappa = 0.410). For AV, EV and Mpn the m-RT-PCR-ELISA preliminary could be qualified as very good, based on the data derived on culture supernatants. Information about the validity for Cpn is limited.
The m-RT-PCR-ELISA is a feasible, sensitive and specific method for detection of a broad spectrum of organisms. It is suitable for individual as well as epidemiological diagnosis.
Journal of Clinical Virology 07/2004; 30(2):165-74. · 3.29 Impact Factor
[show abstract][hide abstract] ABSTRACT: Approximately 1,000 million infections with dengue viruses are estimated to occur annually. The majority of the cases develop mild disease, whereas only small proportion of the infected individuals develop severe hemorrhagic manifestations at the end of the acute phase of illness. In this study, the value of plasma levels of vascular cell adhesion molecule 1 (VCAM-1) in the pathogenesis and prognosis of dengue illness was investigated in children with dengue infections of varying severity. The plasma levels of soluble VCAM-1 (sVCAM-1) were measured in serial plasma samples obtained from 168 children aged between 7 months and 14 years with confirmed dengue infection. Of those children, 71 were suffering from dengue fever, 30 were suffering from dengue hemorrhagic fever, and 67 were suffering from dengue shock syndrome. Plasma samples obtained from 21 patients with febrile illness other than dengue served as controls. A commercially available kit (R&D Systems, Oxon, UK) was used to measure the levels of sVCAM-1 in plasma samples. sVCAM-1 was elevated during acute dengue infection, and significantly elevated among dengue shock syndrome patients as compared to dengue fever or dengue hemorrhagic fever patients (P < 0.05). Statistical analysis revealed that sVCAM-1 was associated with dengue disease severity and the time post infection (acute vs. convalescent phase) and not with age, sex, or previous exposure of the patients to dengue infection. A significant difference was found in the plasma levels of sVCAM-1 between dengue shock syndrome and dengue fever patients, however, the prognostic value of this marker in the acute stage of dengue illness proved to be limited. These data also favor to study the further elucidation of the role of sVCAM-1 in the pathogenesis of dengue infections.
Journal of Medical Virology 03/2004; 72(3):445-50. · 2.37 Impact Factor
[show abstract][hide abstract] ABSTRACT: A major drawback of modern society's rapidly increasing mobility is the ease with which dangerous infections can be imported into Europe. Often these infections are not diagnosed because physicians are not familiar with the symptoms and laboratory tests are not always available in local diagnostic centres. Improving diagnostics is the most important step in detecting and dealing with these pathogens and quality control measures are, therefore, essential tools.
To assess the diagnosis of imported dengue virus infections in Europe by (1) running a pre-evaluation panel (four serum samples, sent out in 1999) and optimising sample preparation and shipping procedures and (2) initiating an External Quality Assurance (EQA) program (20 serum samples, sent out in 2002).
All serum samples sent out were to be tested for the presence of dengue virus-specific IgM and IgG. For the pre-evaluation panel, four samples were distributed (one sample IgM+/IgG+, one sample IgM-/IgG+, two samples IgM-/IgG-) and for the EQA 20 samples (12 samples IgM+/IgG+, five samples IgM-/lgG+, one sample lgM+/IgG- two samples IgM-/IgG-). 13 laboratories took part in the pre-evaluation panel and 18 laboratories participated in the first EQA run.
For the pre-evaluation panel, the participants reported concurrent and correct results for 88% of the IgG-positive samples and for 100% of the IgG-negative samples. The results for the IgM-positive sample were correct in 91% of the reported tests and in 97% of the IgM-negative samples. For the EQA, the participants reported concurrent and correct results for 71% of the IgG-positive samples and 89% of the IgG-negative samples. 58% concurrent and correct results were reported for the IgM-positive samples and 97% for the IgM-negative samples.
The results presented here demonstrate the importance of quality measures for imported viral pathogens like dengue viruses and clearly indicate the need for improving the existing test systems.
Journal of Clinical Virology 03/2004; 29(2):105-12. · 3.29 Impact Factor
[show abstract][hide abstract] ABSTRACT: Accurate and timely diagnosis of dengue virus (DEN) infections is essential for the differential diagnosis of patients with febrile illness and hemorrhagic fever. In the present study, the diagnostic value of a newly developed immune-complex dissociated nonstructural-1 (NS-1) antigen dot blot immunoassay (DBI) was compared to a commercially available DEN antigen detection kit (denKEY Blue kit; Globio Co., Beverly, Mass.) and a reverse transcription-PCR (RT-PCR) kit. Serial serum or plasma samples (n = 181) obtained from 55 acute DEN-infected patients were used. In samples obtained from 32 of these 55 DEN-infected patients, viral RNA could be detected by RT-PCR. DEN antigen was detected in only 10 of these 55 patient samples by using the denKEY kit. When these samples were treated with acid to release the immune-complex-associated NS-1 antigen for detection by DBI, 43 of these 55 patients were found to be positive for DEN NS-1 antigen. In nondissociated samples, 22 of these patients were found to be positive by the DBI. In the presence of DEN-specific immunoglobulin M antibodies, both viral RNA and DEN (NS-1) antigen could be detected. The number of positive samples identified by RT-PCR and DBI from these patients with primary DEN infections varied between 28 and 78%. In secondary DEN infections, the number of samples that tested positive by the DBI after immune-complex dissociation (DIS-DBI) was 25% higher than the number of samples that tested positive by RT-PCR and was 35% higher than that determined by nondissociated antigen (NDIS-DBI) detection. We conclude that the denKEY kit has limited diagnostic value for acute DEN infections compared to the RT-PCR and the NDIS-DBI and DIS-DBI methods. We clearly demonstrate that in secondary DEN infections the dissociation of NS-1 immune complexes is essential for early diagnosis of DEN infections.
Journal of Clinical Microbiology 10/2003; 41(9):4154-9. · 4.07 Impact Factor
[show abstract][hide abstract] ABSTRACT: Ebola virus (EBOV) is a member of the family Filoviridae and is classified as a biosafety level 4 virus. This classification makes the preparation of antigen and performance of diagnostic assays time-consuming and complicated. The objective of this study was to evaluate the value of EBOV immunoassays based on recombinant nucleoprotein (r-NP) and recombinant VP35 (r-VP35) using large serum panels of African origin and from primates. Furthermore, we investigated whether the results obtained with EBOV r-VP35 enzyme-linked immunosorbent assay (ELISA) could improve on the findings obtained with the EBOV r-NP ELISA. The full-length EBOV NP and VP35 of the EBOV subtype Zaire were expressed as histidine-tagged recombinant proteins in the baculovirus expression system. The antigenic reactivity and specificity of these recombinant proteins were determined by Western blotting and ELISA using EBOV specific monoclonal antibodies. The results obtained with the r-NP and r-VP35 ELISAs were compared with the results obtained in an indirect immunofluorescence assay based on native EBOV subtype Zaire. EBOV specific monoclonal antibodies reacted specifically with the respective proteins in both Western blot and ELISA. Five hundred and twenty six samples from humans and primates were tested with r-NP and r-VP35 ELISAs. Monkey serum samples positive for EBOV subtype Reston and Zaire were both positive in the EBOV r-NP ELISA, whereas only the EBOV Zaire infected monkeys were positive in the r-VP35 ELISA. The sensitivity and specificity values of the EBOV recombinants' ELISAs compared to those of the immunofluorescence assay were 92% and 99% for r-NP and 44% and 100% for r-VP35. r-NP ELISA proved to be a sensitive and specific assay for EBOV diagnosis and for epidemiological studies for both EBOV subtypes Reston and Zaire. The use of r-VP35 in an ELISA format has no additional value for EBOV serodiagnosis.
Microbes and Infection 05/2003; 5(5):379-85. · 2.92 Impact Factor
[show abstract][hide abstract] ABSTRACT: The kinetics of total and dengue virus-specific immunoglobulin E (IgE) were studied in serial serum samples obtained from 168 patients, 41 of whom suffered from primary dengue virus infection and 127 suffered from secondary dengue virus infection. Seventy-one patients were classified as dengue fever, 30 as dengue hemorrhagic fever, and 67 as dengue shock syndrome. A control group included single serum samples from patients with a herpes virus infection (n = 14), non-dengue febrile patients (n = 10), and healthy blood donors (n = 10). Patients with dengue virus infection had higher levels of total and dengue virus-specific IgE than non-dengue patients (P < 0.05). Patients with secondary dengue virus infections had not significantly increased levels of both total and dengue virus-specific IgE in the acute phase of disease compared to patients with primary dengue virus infections. Dengue virus-specific IgE was significantly higher in dengue hemorrhagic fever and/or dengue shock syndrome patients compared to dengue fever and non-dengue patients (P < 0.05). In conclusion, this study showed elevated total and dengue virus-specific IgE serum antibody levels in the acute stage of disease. Therefore, measurement of both total and dengue virus-specific IgE serum antibodies can be used as an additional prognostic marker in the development of severe complications in dengue virus infections. In addition, the presence and increase of dengue virus-specific IgE serum antibodies in patients with dengue virus infections is suggestive of the pathogenetic role that IgE may play in the hemostatic disorders observed in dengue hemorrhagic fever and dengue shock syndrome.
Journal of Medical Virology 05/2003; 70(1):91-8. · 2.37 Impact Factor
[show abstract][hide abstract] ABSTRACT: It has long been recognised that neuroinvasion may occur as a rare complication of measles. According to cases reported in the medical literature , measles virus (MV) can persist in the central nervous system producing chronic neurological disease without systemic viremia [2, 3]. In most industrialised countries, the introduction of live attenuated measles vaccines has resulted in the virtual disappearance of measles as a common childhood disease and strongly reduced the numbers of patients with MV-related neurological disease. However, measles did not completely disappear: occasional clinical cases are still observed due to importation of MV from endemic areas , and larger outbreaks continue to occur amongst clusters of unvaccinated individuals . It is difficult to assess how many people are exposed to wild-type MV as a result of these cases, but the virus is only rarely considered as a possible cause of neurological symptoms. The aim of the present study was to identify undiagnosed cases of MV-related encephalitis. Combined evaluation of clinical data, results of diagnostic serological tests and reverse transcriptase polymerase chain reactions carried out on cerebrospinal fluid and bronchoalveolar lavage specimens may shed light on the aetiology of these cases of encephalitis. A retrospective analysis was performed on 53 patients admitted to our hospital during 1998 with encephalitis of unknown origin. Their mean age was 48 years (range, 19–74 years). Clinical features included fever, headache, facial weakness, altered mental status, seizures, impaired hearing, motor disturbances, limb paralysis and respiratory distress. Patients were tested for several viral infections that may be associated with encephalitis including herpes simplex viruses 1 and 2, cytomegalovirus, Epstein-Barr virus, JC virus (the causative agent of progressive multifocal leukoencephalopathy), tick-borne encephalitis virus, dengue virus, HIV-1 and HIV-2 and Mycoplasma pneumoniae. All patients were negative for all of these agents. In the present study, serum and cerebrospinal fluid samples were tested for the presence of MV-specific IgM and IgG antibodies using a commercially available IgM capture enzyme immunoassay (Meddens Diagnostics, The Netherlands) and an enzyme immunoassay developed in-house based on whole virus, respectively. Two patients, 29 and 48 years of age, were found to be MV IgM-positive in both serum and cerebrospinal fluid, and in one 73-year-old patient borderline levels of MV-specific IgM serum antibodies were detected. This last patient had chronic lymphatic leukaemia and was undergoing immunosuppressive treatment. During the previous 2 years he had suffered recurrent opportunistic infections, with fever and pneumonia, zoster, vasculitis, and hepatitis. Serum samples collected 1 year before his encephalitis was diagnosed were MV IgM-negative and contained low levels of MV-specific IgG antibodies. An MV-specific reverse transcriptase polymerase chain reaction  was carried out on a bronchoalveolar lavage sample to diagnose the cause of the patient’s pneumonia that had developed during his encephalitis and was found positive. Sequence analysis of the amplicon demonstrated that the virus belonged to genotype C2 (GenBank, http://www.ncbi.nlm.nih.gov/Genbank/; accession number AF519493), which was a common European genotype during the last decade of the previous century. Blast analysis identified a virus isolated in 1992 in Tilburg, The Netherlands, as the only identical sequence in the GenBank database, but almost identical viruses were involved in a measles outbreak in Luxembourg in 1996 . The results of the present study strongly suggest that undiagnosed encephalitis may be associated with MV infection: in 2 of 53 undiagnosed encephalitis cases, MVspecific IgM antibodies were found in serum and cerebrospinal fluid, strongly indicating that these patients were suffering from an MV infection. In a third patient,
European Journal of Clinical Microbiology 01/2003; 21(12):900-1. · 3.02 Impact Factor
[show abstract][hide abstract] ABSTRACT: In the Netherlands 73% of cases of neonatal herpes are caused by herpes simplex virus type 1 (HSV-1), whereas in the United States a majority are caused by HSV type 2 (HSV-2). GOAL To understand this difference we undertook a seroepidemiological study on the prevalence of HSV-1 and HSV-2 among pregnant women.
Type-specific antibodies to HSV-1 and HSV-2 were detected by enzyme-linked immunosorbent assay (ELISA) in serum samples from 1,507 pregnant women in Amsterdam, Rotterdam, and Nijmegen.
The prevalence of HSV-1 was 61% in Nijmegen, 73% in Amsterdam, and 75% in Rotterdam. The prevalence of HSV-2 was 11% in Nijmegen, 35% in Amsterdam, and 27% in Rotterdam.
The seroprevalence of HSV-1 and HSV-2 antibodies among pregnant women in the Netherlands shows significant geographical differences, which were attributed to ethnical variation. However, the epidemiologic differences did not correlate with the incidence of neonatal herpes in the Netherlands.
Sex Transm Dis 12/2002; 29(11):710-4. · 2.59 Impact Factor
[show abstract][hide abstract] ABSTRACT: Flavivirus infections are a significant public health problem, since several members of the Flaviviridae family are highly pathogenic to humans. Accurate diagnosis and differentiation of the infecting virus is important, especially in areas where many flaviviruses are circulating. In this study we evaluated a newly developed commercially available immunofluorescence assay (IFA) (INDX, Baltimore, MD, USA) for the detection of IgM and IgG antibodies against dengue virus, yellow fever virus, Japanese encephalitis virus and West Nile virus. IFA was compared with standard diagnostic enzyme immunoassays (EIAs) specific for the detection of IgM and IgG antibodies against these viruses. Forty-seven serum samples from patients with a defined flavivirus infection were tested. As controls, serum samples from individuals with antibodies against tick-borne encephalitis virus and hepatitis C virus as well as healthy individuals were included. The results obtained from this study indicate that IFA showed a significantly better discrimination for flavivirus specific IgM antibodies than did the standard IgM specific EIAs (the overall cross-reactivity varied between 4 and 10% by IFA and 30-44% by EIA for the respective viruses). In contrast, the detection of flavivirus specific IgG antibodies showed high cross-reactions in both IFA and EIAs (overall cross-reactivity 16-71 and 62-84%, respectively). This study clearly stated the complexity of flavivirus diagnosis, showing that one cannot rely on one assay or search for one virus only. The flavivirus IFA is a useful tool for the identification of flavivirus infections during the acute stage of disease. In particular, IFA can be an important diagnostic tool for testing samples from travellers who have been accidentally exposed to these viruses.
Microbes and Infection 11/2002; 4(12):1209-15. · 2.92 Impact Factor
[show abstract][hide abstract] ABSTRACT: Anti-galactocerebroside (GalC) antibodies are reported to be present in GBS patients with preceding Mycoplasma pneumoniae (MP) infection. We investigated the presence of anti-GalC reactivity in serum of a large group of GBS patients using ELISA and compared this with healthy controls and individuals with an uncomplicated MP infection. Anti-GalC antibody reactivity was present in 12% of the GBS patients. Furthermore, anti-GalC antibodies were associated with MP infections, a relatively mild form of the disease and demyelinating features. Anti-GalC antibodies cross-reacted with MP antigen. In conclusion, anti-GalC antibodies in GBS patients may be induced by molecular mimicry with MP.
Journal of Neuroimmunology 10/2002; 130(1-2):179-83. · 3.03 Impact Factor