Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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    We will mail you new results for this query: keywords==Serology
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The relationship between the presence of antibodies and direct detection of Toxoplasma gondii in slaughtered calves and cattle in four European countries
Opsteegh, M. ; Spano, F. ; Aubert, D. ; Balea, A. ; Burrells, A. ; Cherchi, S. ; Cornelissen, J.B.W.J. ; Dam-Deisz, C. ; Guitian, J. ; Györke, A. ; Innes, E.A. ; Katzer, F. ; Limon, G. ; Possenti, A. ; Pozio, E. ; Schares, G. ; Villena, I. ; Wisselink, H.J. ; Giessen, J.W.B. van der - \ 2019
International Journal for Parasitology 49 (2019)7. - ISSN 0020-7519 - p. 515 - 522.
Cattle - Detection - Mouse bioassay - PCR - Serology - Toxoplasma gondii

In cattle, antibodies to Toxoplasma gondii infection are frequently detected, but evidence for the presence of T. gondii tissue cysts in cattle is limited. To study the concordance between the presence of anti-T. gondii IgG and viable tissue cysts of T. gondii in cattle, serum, liver and diaphragm samples of 167 veal calves and 235 adult cattle were collected in Italy, the Netherlands, Romania and the United Kingdom. Serum samples were tested for anti-T. gondii IgG by the modified agglutination test and p30 immunoblot. Samples from liver were analyzed by mouse bioassay and PCR after trypsin digestion. In addition, all diaphragms of cattle that had tested T. gondii-positive (either in bioassay, by PCR on trypsin-digested liver or serologically by MAT) and a selection of diaphragms from cattle that had tested negative were analyzed by magnetic capture quantitative PCR (MC-PCR). Overall, 13 animals were considered positive by a direct detection method: seven out of 151 (4.6%) by MC-PCR and six out of 385 (1.6%) by bioassay, indicating the presence of viable parasites. As cattle that tested positive in the bioassay tested negative by MC-PCR and vice-versa, these results demonstrate a lack of concordance between the presence of viable parasites in liver and the detection of T. gondii DNA in diaphragm. In addition, the probability to detect T. gondii parasites or DNA in seropositive and seronegative cattle was comparable, demonstrating that serological testing by MAT or p30 immunoblot does not provide information about the presence of T. gondii parasites or DNA in cattle and therefore is not a reliable indicator of the risk for consumers.

The development of a multiplex serological assay for avian influenza based on Luminex technology
Germeraad, Evelien ; Achterberg, René ; Venema, Sandra ; Post, Jacob ; Leeuw, Olav de; Koch, Guus ; Wal, Fimme Jan van der; Beerens, Nancy - \ 2019
Methods : a companion to Methods in enzymology 158 (2019). - ISSN 1046-2023 - p. 54 - 60.
Avian influenza - Luminex - Multiplex - Poultry - Serology - Subtyping

Avian influenza (AI) is an infectious disease in birds with enormous impact on the poultry sector. AI viruses are divided into different subtypes based on the antigenicity of their surface proteins haemagglutinin (HA) and neuraminidases (NA). In birds, 16 HA subtypes and 9 NA subtypes are detected in different combinations. Traditional serological methods for the subtyping of AI antibodies are labour-intensive and have to be performed for each HA and NA subtype separately. This study describes the development of a multiplex serological assay for subtyping AI antibodies in poultry sera using Luminex xMAP technology. This multiplex assay allows the detection of all AI serotypes in one single assay. For all HA and NA subtypes, recombinant proteins were purified and coupled to colour-coded magnetic bead sets. Using the Luminex MAGPIX device, binding of serum antibodies to the antigens on the bead sets is detected by fluorescent secondary antibodies, and the different bead sets are identified. The results of the multiplex assay were compared with that of the traditional singleplex assays. We show that serotyping using the novel multiplex serological assay is consistent with the results of the traditional assays in 97.8% of the reference sera and in 90.8% of the field sera. The assay has a higher sensitivity than the traditional assays, and requires a smaller sample volume. Therefore, the assay will allow complete AI-serotyping in small volumes of field sera, which will improve the monitoring of AI subtypes circulating in poultry significantly.

A bead-based suspension array for the detection of Salmonella antibodies in pig sera
Wal, Fimme J. van der; Achterberg, René P. ; Maassen, Catharina B.M. - \ 2018
BMC Veterinary Research 14 (2018)1. - ISSN 1746-6148
Bead-based suspension array - LPS - Pig - Salmonella - Serology - Swine - Triazine chemistry

Background: Slaughter pigs are monitored for the presence of the zoonotic pathogen Salmonella, using both serology and bacteriology. ELISAs used to investigate pig herds are based on the detection of antibodies against components of the Salmonella cell envelope. Nearly all Salmonella isolates in food-producing animals are serovars of Salmonella enterica subspecies enterica, distributed over various serogroups as determined by the composition of their lipopolysaccharide (LPS). ELISAs for Salmonella serology are usually based on serogroup B and C1 LPS, often combined with serogroup D or E LPS. Although C2 LPS may improve serology, use of C2 LPS in a broad ELISA was never achieved. Results: To enable detection of serum antibodies against Salmonella in pigs, a bead-based suspension array was developed with five LPS variants (B, 2× C1, C2, D1), each conjugated to a different bead set using triazine chemistry. Reactivity of the beads was confirmed with rabbit agglutination sera and with experimental pig sera. With a mixture of bead sets, 175 sera from slaughter pigs were investigated for the presence of antibodies against Salmonella. With a combination of ROC analysis (B and D LPS) and a prevalence estimation based on historic data (C LPS), individual cut-offs were defined for each LPS-conjugated bead set, and assay performance was evaluated. Results of the suspension array (BC1C1C2D) suggest that more pigs are seroconverted than indicated by a commercial BC1D1-ELISA, and that most of these extra seropositive samples give a signal on one of the beads with C LPS. These results show that expansion of a standard panel with more C LPS variants improves antibody detection. Conclusions: A suspension array for Salmonella serology in pigs was developed, that detects more seropositive sera than ELISA, which is achieved by expanding the panel of Salmonella LPS variants, including C2 LPS. The results demonstrate that bead-based suspension arrays allow for testing of pig sera, with the advantage of being able to set cut-offs per antigen. Ultimately, this type of assay can be applied in routine veterinary serology to test for antibodies against multiple Salmonella serovars (or other pathogens) in one single serum sample, using up-to-date antigen panels.

Pre-screening of crude peptides in a serological bead-based suspension array
Jelsma, Tinka ; wal, Fimme J. van der; Fijten, Helmi ; Dailly, Nicolas ; Dijk, Evert van; Loeffen, Willie L. - \ 2017
Journal of Virological Methods 247 (2017). - ISSN 0166-0934 - p. 114 - 118.
Classical swine fever virus - HIV - Parvovirus - Peptide - Serology - Suspension array

Most serological assays detect antibody responses in biological samples through affinity of serum antibodies for antigens provided in the assay. Certain antigens, however, may be difficult to produce and/or may contain unwanted epitopes. In these cases, a practical alternative may be the use of peptides as representatives for specific epitopes. Peptides can be obtained after purification in large quantities for a modest price, but screening of a large set of peptides during development may be relatively expensive. To cut costs of screening peptides for a new serological assay, the concept was investigated of using cheap non-purified (crude) peptides instead of purified peptides.Peptides were selected that represent three well-described linear epitopes of viral proteins: VP2 of canine parvovirus (CPV), gp41 of human immunodeficiency virus (HIV) and E2 of classical swine fever virus (CSFV). Crude and purified biotinylated peptides with either a short or long spacer between the biotin and the epitope were used to test their capability to bind antibodies in a bead-based suspension array.The results show that, in a bead-based suspension array, crude peptides can function as antigen for specific monoclonal antibodies, and that the acquired signals are less than with purified peptides. CSFV-derived crude peptides were also able to detect specific antibodies in swine serum, indicating the applicability of crude peptides for pre-screening large numbers of different peptides during the development of serological peptide-based assays.

Inter-laboratory study to characterize the detection of serum antibodies against porcine epidemic diarrhoea virus
Strandbygaard, Bertel ; Lavazza, Antonio ; Lelli, Davide ; Blanchard, Yannick ; Grasland, Béatrice ; Poder, Sophie Le ; Rose, Nicolas ; Steinbach, Falko ; Poel, Wim H.M. van der; Widén, Frederik ; Belsham, Graham J. ; Bøtner, Anette - \ 2016
Veterinary Microbiology 197 (2016). - ISSN 0378-1135 - p. 151 - 160.
ELISA - PEDV - Porcine coronavirus - Ring trial - Serology

Porcine epidemic diarrhea virus (PEDV) has caused extensive economic losses to pig producers in many countries. It was recently introduced, for the first time, into North America and outbreaks have occurred again in multiple countries within Europe as well. To assess the properties of various diagnostic assays for the detection of PEDV infection, multiple panels of porcine sera have been shared and tested for the presence of antibodies against PEDV in an inter-laboratory ring trial. Different laboratories have used a variety of “in house” ELISAs and also one commercial assay. The sensitivity and specificity of each assay has been estimated using a Bayesian analysis applied to the ring trial results obtained with the different assays in the absence of a gold standard. Although different characteristics were found, it can be concluded that each of the assays used can detect infection of pigs at a herd level by either the early European strains of PEDV or the recently circulating strains (INDEL and non-INDEL). However, not all the assays seem suitable for demonstrating freedom from disease in a country. The results from individual animals, especially when the infection has occurred within an experimental situation, show more variation.

The serological response against foot and mouth disease virus elicited by repeated vaccination of dairy cattle
Elnekave, Ehud ; Dekker, Aldo ; Eble, Phaedra ; Kluitenberg-van Hemert, Froukje ; Gelman, Boris ; Storm, Nick ; Klement, Eyal - \ 2016
Vaccine 34 (2016)41. - ISSN 0264-410X - p. 4920 - 4926.
Cattle - Dairy - FMD - Neutralizing antibody titers (NAT) - Repeated vaccinations - Serology

In Israel, cattle are annually vaccinated against foot and mouth disease (FMD). If infections with FMD virus occur in dairy farms it mainly involves heifers and calves, while older dairy cows seldom become infected. We hypothesized that this difference in susceptibility between adult cows and the young heifers and calves is due to stronger and more stable immune response elicited by multiple vaccinations. In order to test this hypothesis, 99 dairy cattle, divided into six groups according to number of prior vaccinations, were annually vaccinated with a trivalent vaccine (A, O and Asia-1) and followed during two consecutive years. In total 988 sera were sampled at 11 time points. Virus neutralization tests (VNT) were performed in order to determine the neutralizing antibody titers (NAT) against the vaccine homologous serotypes: O-4625, O-Manisa, Asia-1-Shamir and the heterologous serotype A-Turkey-20/2006. A similar NAT pattern was observed to all serotypes and therefore statistical analysis was restricted to O-4625 serotype. In the ‘high vaccination’ groups (cows that were vaccinated at least four times before the study), high NAT were found on the beginning of the trial and no or only a mild increase of NAT was observed following further vaccinations. Additionally, in the ‘high vaccination’ groups, the percentage of cows that had a NAT higher than 2.0 (log10) by the end of the 1st year was significantly higher than in the ‘low vaccination’ groups (cows vaccinated only three times or less before the study). We conclude that starting from the 5th vaccination, the NAT increase following vaccination is mild and NAT are persistent, suggesting reduction of the frequency of routine vaccination after multiple vaccinations is possible.

The long term effect of age and maternally derived antibodies against foot and mouth disease on the serological response following vaccination in young dairy calves
Elnekave, Ehud ; Dekker, Aldo ; Eble, Phaedra ; Kluitenberg-van Hemert, Froukje ; Gelman, Boris ; Storm, Nick ; Klement, Eyal - \ 2016
Vaccine 34 (2016)41. - ISSN 0264-410X - p. 4927 - 4934.
Calves - Dairy - FMD - Maternally derived antibodies (MDA) - Neutralization antibody titers (NAT) - Serology

In Israel, occurrence of foot and mouth disease (FMD) in dairy farms is rare. However, when FMD outbreaks occur, dairy calves are the most affected, despite routine vaccination. Contradictory findings exist regarding the effect of age and maternally derived antibodies (MDA) on the serological response following vaccinations against FMD in dairy calves. Furthermore, the long term effect of FMD vaccination regimen during early life was rarely assessed. This study was conducted in order to assess both the short and long term effects. In total 44 non-vaccinated calves were divided into four groups of different age. Calves were vaccinated up to four times and 484 serum samples were collected on 11 time points in a period of 70 weeks. Virus neutralizing tests were performed in order to determine the neutralizing antibody titers (NAT) against the vaccine strains (homologous serotypes): O-4625, O-Manisa, ASIA-1-Shamir and the heterologous serotype A-Turkey-20/2006. A similar NAT pattern was observed to all serotypes and therefore statistical analysis was restricted to O-4625 serotype. The MDA titer was negatively associated with the age of the calves and the MDA half-life was 22 days. We demonstrated that early vaccination of calves (younger than three months) resulted in low NAT, even after four repeated vaccinations, compared with vaccination of calves older than three months. The percentage of time in which these calves had a NAT above 2.0 (log10) between the age of six months and 1.5 years was significantly lower compared to older calves (older than three months). Additionally, we found that by increasing the frequency of vaccination in calves older than three months, it is possible to reach high NAT by the age of one year. Adoption of such a vaccination regimen in Israel as well as other FMD endemic countries may allow better protection against FMD in dairy calves and reduction in FMD incidence.

Feasibility of a simple microsieve-based immunoassay platform
Zweitzig, Daniel R. ; Tibbe, Arjan G. ; Nguyen, Ai T. ; Rijn, Cees J.M. van; Kopnitsky, Mark J. ; Cichonski, Kathleen ; Terstappen, Leon W.M.M. - \ 2016
Journal of Immunological Methods 437 (2016). - ISSN 0022-1759 - p. 21 - 27.
Diagnosis - Disease - Immunoassay - Infectious - Microsieve - Serology

The intrinsic properties of silicon microsieves, such as an optically flat surface, high overall porosity, and low flow resistance have led to an increasing number of biotechnology applications. In this report, the feasibility of creating a microsieve-based immunoassay platform was explored. Microsieves containing 5μm pores were coupled with poly-acrylic acid chains, and then mounted into a plastic holder to enable rapid reagent exchanges via a wicking mechanism. The mounted microsieves were coated with infectious disease-related antigens at [2.5 and 25μg/mL], [20 and 50μg/mL], and [20 and 100μg/mL] to facilitate detection of serum-derived human antibodies against Rubella (3-day measles), B. burgdorferi (Lyme disease), or T. pallidum (syphilis), respectively. The prototype microsieve-based immunoassay platform was able to distinguish positive control sera containing antibodies against Rubella, T. pallidum, and B. burgdorferi from negative control sera with similar qualitative results as FDA-approved ELISA tests. Testing of a WHO IgG syphilitic standard at 0.3, 0.15, 0.075, 0.0375, and 0.01875IU/mL demonstrated that the T. pallidum microsieve assay is able to distinguish disease-specific IgG signal from background signal at similar, and possibly lower, levels than the corresponding ELISA. The T. pallidum microsieve assay prototype also differentiated positive clinical serum samples from negative donor samples, and the results were in good agreement with ELISA (R2 =0.9046). These feasibility studies demonstrate the potential for utilizing microsieves, along with a reagent wicking device, as a simple diagnostic immunoassay platform.

Prevalence of Anti-Hepatitis E Virus Antibodies and First Detection of Hepatitis E Virus in Wild Boar in Slovenia
Žele, Diana ; Fernandes Barry, Aline ; Honing-Hakze, Renate van der; Vengušt, Gorazd ; Poel, W.H.M. Van Der - \ 2016
Vector-Borne and Zoonotic Diseases 16 (2016)1. - ISSN 1530-3667 - p. 71 - 74.
Hepatitis E - Hepatitis E virus - PCR - Serology - Slovenia - Wild boar

Hepatitis E is an emerging zoonotic disease caused by hepatitis E virus (HEV). In this study, we investigated HEV presence in a wild boar (Sus scrofa) population of Slovenia. A total of 288 wild boar serum samples were collected throughout the country, and HEV infection was investigated by serology, using enzyme-linked immunosorbent assay (ELISA) and by HEV RNA detection using a real-time PCR assay. Antibodies against HEV were detected in 30.2% (87/288) of animals tested, whereas HEV RNA was detected in only one sample. This is the first evidence of HEV presence in the wild boar population in Slovenia, and these results suggest that these animals are part of the HEV epidemiological cycle in the country.

Detection of serum neutralizing antibodies to Simbu sero-group viruses in cattle in Tanzania
Mathew, Coletha ; Klevar, S. ; Elbers, A.R.W. ; Poel, W.H.M. van der; Kirkland, P.D. ; Godfroid, J. ; Mdegela, R.H. ; Mwamengele, G. ; Stokstad, M. - \ 2015
BMC Veterinary Research 11 (2015). - ISSN 1746-6148 - 9 p.
Antibody ELISA - Orthobunyavirus - Schmallenberg virus - Serology - Virus neutralizing test

Background: Orthobunyaviruses belonging to the Simbu sero-group occur worldwide, including the newly recognized Schmallenberg virus (SBV) in Europe. These viruses cause congenital malformations and reproductive losses in ruminants. Information on the presence of these viruses in Africa is scarce and the origin of SBV is unknown. The aim of this study was to investigate the presence of antibodies against SBV and closely related viruses in cattle in Tanzania, and their possible association with reproductive disorders. Results: In a cross-sectional study, serum from 659 cattle from 202 herds collected in 2012/2013 were analyzed using a commercial kit for SBV ELISA, and 61 % were positive. Univariable logistic regression revealed significant association between ELISA seropositivity and reproductive disorders (OR = 1.9). Sera from the same area collected in 2008/2009, before the SBV epidemic in Europe, were also tested and 71 (54.6 %) of 130 were positive. To interpret the ELISA results, SBV virus neutralization test (VNT) was performed on 110 sera collected in 2012/2013, of which 51 % were positive. Of 71 sera from 2008/2009, 21 % were positive. To investigate potential cross reactivity with related viruses, 45 sera from 2012/2013 that were positive in SBV ELISA were analyzed in VNTs for Aino, Akabane, Douglas, Peaton, Sabo, SBV, Sathuperi, Shamonda, Simbu and Tinaroo viruses. All 45 sera were positive for one or more of these viruses. Twenty-nine sera (64.4 %) were positive for SBV, and one had the highest titer for this virus. Conclusions: This is the first indication that Aino, Akabane, Douglas, Peaton, Sabo, SBV, Sathuperi, Shamonda and Tinaroo viruses circulate and cause negative effect on reproductive performance in cattle in Tanzania. SBV or a closely related virus was present before the European epidemic. However, potential cross reactivity complicates the interpretation of serological studies in areas where several related viruses may circulate. Virus isolation and molecular characterization in cattle and/or vectors is recommended to further identify the viruses circulating in this region. However, isolation in cattle is difficult due to short viremic period of 2 to 6 days, and isolation in vectors does not necessarily reflect the situation in cattle.

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