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Christina Strube - One of the best experts on this subject based on the ideXlab platform.

  • apparent prevalence of and risk factors for infection with ostertagia ostertagi fasciola hepatica and Dictyocaulus viviparus in swiss dairy herds
    Veterinary Parasitology, 2018
    Co-Authors: Caroline F Frey, Christina Strube, R Eicher, Katharina Raue, Michele Bodmer, Brigitte Hentrich, Bruno Gottstein, Nelson Marreros
    Abstract:

    Infections with helminth parasites can negatively affect performance of dairy cows. Knowledge on infection intensity, spatial distributions and risk factors are key to develop targeted treatment strategies. Canada and most EU countries have conducted large investigations, but respective data for Switzerland were missing. We now performed a bulk tank milk serosurvey for Ostertagia ostertagi, Fasciola hepatica, and Dictyocaulus viviparus on a total of 1036 voluntarily participating dairy herds that were sampled at confinement periods, i.e. in winter 2014/15 or 2015/16, respectively. All samples were analyzed with commercial ELISAs for antibodies (AB) against O. ostertagi and F. hepatica, and those of the first sampling period additionally with an in-house ELISA for AB against D. viviparus. Testing for the latter parasite was not done in the second year of the study, as the sampling period might have missed infections due to the short lived nature of specific antibodies. The possible influence of geographic, climatic, and farm management variables on AB levels were assessed for each parasite using scanning cluster and multiple regression analysis. Overall seroprevalence for O. ostertagi was 95.5% (95% C.I.: 94.0-96.6), with a mean optical density ratio (ODR) of 0.83, for F. hepatica 41.3% (95% C.I.: 38.3-44.4), and for D. viviparus 2.9% (95% C.I.: 1.6-4.7). There were no significant differences between the two sampling periods. For all parasites, significant geographic clusters of higher AB levels could be established. Furthermore, AB levels against all three parasites were positively correlated with each other, indicating either cross-reactions or co-infections. For O. ostertagi, herd size and percentage of pasture in the ration were positively correlated with AB levels. For F. hepatica, altitude above sea level (a.s.l.) positively, and milk production per cow and year was negatively correlated with AB levels. This work provides baseline data for further studies performing in-depth risk factor analysis and investigating management as well as targeted treatment options to control the parasites.

  • biological function of Dictyocaulus viviparus asparaginyl peptidase legumain 1 and its suitability as a vaccine target
    Parasitology, 2017
    Co-Authors: Julia Holzhausen, Claas Haake, Sabine Schicht, Elisabeth Kremmer, Petra Hinse, Daniela Jordan, Christina Strube
    Abstract:

    The present study characterized the biological function of the asparaginyl peptidase legumain-1 (LEG-1) of the bovine lungworm Dictyocaulus viviparus and its suitability as a recombinant vaccine against dictyocaulosis. Quantitative real-time PCR and immunoblot analysis revealed LEG-1 to be almost exclusively transcribed and expressed in parasitic lungworm stages. Immunohistochemistry localized the enzyme in the parasite's gut, which was confirmed by immunoblots detecting LEG-1 in the gut as well as male testes. LEG-1 was recombinantly (rLEG-1) expressed in the yeast Pichia pastoris and subsequently analysed in activity assays for its enzyme functions and substrate specificity. For sufficient functionality, rLEG-1 needed trans-activation through D. viviparus cathepsin L-2, indicating a novel mechanism of legumain activation. After trans-activation, rLEG-1 worked best at pH 5.5 and 35-39 degrees C and cleaved a legumain-specific artificial substrate as well as the natural substrates bovine collagen types I and II. In a clinical vaccination trial, rLEG-1 did not protect against challenge infection. Results of in vitro characterization, transcription pattern and localization enhance the presumption that LEG-1 participates in digestion processes of D. viviparus. Since rLEG-1 needs trans-activation through a cathepsin, it is probably involved in an enzyme cascade and therefore remains interesting as a candidate in a multi-component vaccine.

  • fatty acid composition of free living and parasitic stages of the bovine lungworm Dictyocaulus viviparus
    Molecular and Biochemical Parasitology, 2017
    Co-Authors: Annchristin Becker, Andrea Springer, Ina Willenberg, Nils Helge Schebb, Pablo Steinberg, Christina Strube
    Abstract:

    The development of parasitic nematodes proceeds via multiple stages, often implicating the necessity to adapt to different environments. Especially the transition from free-living to parasitic stages is accompanied by a significant change in the environmental conditions. To shed light on possible adaptations to these transitions, the fatty acid composition of different developmental stages of the bovine lungworm Dictyocaulus viviparus was investigated. Fatty acids of D. viviparus eggs, the free-living first, second and third larval stage (L1-L3) as well as the parasitic preadult stage and adult male and female worms residing in the lungs of infected hosts were quantified by gas chromatography after transesterification to their fatty acid methyl esters. The fatty acid content and diversity were higher in parasitic stages compared to those of free-living larvae. The most prevalent fatty acids in both parasitic and free-living stages were stearic (C18:0), palmitic (C16:0), palmitoleic (C16:1) and caprylic acid (C8:0). A variety of (poly-)unsaturated FAs was found in the parasitic stages and in the eggs, which was similar to the variety of FAs found in bovine surfactant. This finding indicates that parasitic stages of D. viviparus take up FAs from their environment. While eggs contained the highest concentration of fatty acids, a decrease was observed from eggs to L1 and further from L2 to L3. The lowest concentration was found in 38-days-old L3, which suggests that FAs serve as an energy reserve for the free-living, non-feeding larval stages. The free-living larvae contained mainly saturated fatty acids and only traces of unsaturated fatty acids, which is in contrast to the phospholipid saturation hypothesis of cold tolerance. Instead, a trade-off between desiccation stress and temperature adaptation may favour a higher amount of saturated FAs in the free-living larval stages. Further studies explicitly examining the FA composition of the different classes of lipids are necessary to better describe the adaptative responses of the FA metabolism to different environmental conditions.

  • serological lessons from the bovine lungworm Dictyocaulus viviparus antibody titre development is independent of the infection dose and reinfection shortens seropositivity
    Veterinary Parasitology, 2017
    Co-Authors: Christina Strube, Andrea Springer, Annemarie Schunn, A. B. Forbes
    Abstract:

    Infections with the bovine lungworm Dictyocaulus viviparus, the causative agent of parasitic bronchitis, are accompanied by substantial economic losses due to impacts on production, clinical respiratory disease or even death of diseased cattle. To detect lungworm antibodies in cattle, an enzyme-linked immunosorbent assay (ELISA) based on recombinant major sperm protein (MSP) has been developed. However, it remained unknown whether the infection dose influences antibody levels, and how acquired immunity influences antibody level patterns during reinfections. The latter may lead to low within-herd seroprevalence and thus to negative MSP-ELISA results in examination of bulk tank milk (BTM). Thus, infection experiments with 12 different doses ranging from 10 to 3000 D. viviparus larvae were performed to assess whether the antibody response is dose-dependent. Second, the impact of reinfections on the antibody response was evaluated in infection experiments, and third, antibody patterns in dairy cows during naturally occurring reinfections were assessed in a longitudinal field study based on individual milk samples. Results of this study demonstrate that the rise in MSP antibodies during first infection is dose-independent at infection doses of 25 lungworm larvae and above. However, following reinfections the magnitude and duration of the MSP antibody response are reduced or lacking, depending on the interval to reinfection. The field study revealed short periods of seropositivity as a common pattern in dairy cows subjected to natural D. viviparus reinfections. Low within-herd seroprevalence in dairy herds can thus be a result of continuous reinfections. Low infection doses should not be a barrier to serodiagnosis of lungworm infection in first-time infected cattle.

  • Dictyocaulus viviparus genome variome and transcriptome elucidate lungworm biology and support future intervention
    Scientific Reports, 2016
    Co-Authors: Samantha N Mcnulty, Christina Strube, Bruce A Rosa, John Martin, Rahul Tyagi, Young Jun Choi, Qi Wang, Kymberlie H Pepin, Xu Zhang, Philip Ozersky
    Abstract:

    The bovine lungworm, Dictyocaulus viviparus (order Strongylida), is an important parasite of livestock that causes substantial economic and production losses worldwide. Here we report the draft genome, variome, and developmental transcriptome of D. viviparus. The genome (161 Mb) is smaller than those of related bursate nematodes and encodes fewer proteins (14,171 total). In the first genome-wide assessment of genomic variation in any parasitic nematode, we found a high degree of sequence variability in proteins predicted to be involved host-parasite interactions. Next, we used extensive RNA sequence data to track gene transcription across the life cycle of D. viviparus, and identified genes that might be important in nematode development and parasitism. Finally, we predicted genes that could be vital in host-parasite interactions, genes that could serve as drug targets, and putative RNAi effectors with a view to developing functional genomic tools. This extensive, well-curated dataset should provide a basis for developing new anthelmintics, vaccines, and improved diagnostic tests and serve as a platform for future investigations of drug resistance and epidemiology of the bovine lungworm and related nematodes.

Thomas Schnieder - One of the best experts on this subject based on the ideXlab platform.

  • validation of a Dictyocaulus viviparus msp elisa and cut off adjustment in a one year longitudinal field study in dairy cattle herds
    Veterinary Parasitology, 2012
    Co-Authors: Annemarie Schunn, Thomas Schnieder, A. B. Forbes, Christina Strube
    Abstract:

    Abstract A one-year field study analysing lungworm seropositivity by use of the MSP-ELISA was performed (1) to investigate the antibody dynamics in individual milk samples following field (re-)infections of dairy cows with the bovine lungworm Dictyocaulus viviparus , (2) to investigate the correlation between individual and bulk tank milk (BTM) antibody titres and (3) to review the current individual as well as BTM cut-off value, which was extrapolated from dilution experiments ( Fiedor et al., 2009 ). Over a one-year period individual and BTM samples were collected monthly on 15 dairy farms. Following a critical review of previous cut-off values, individual and BTM samples were subjected to different cut-off thresholds. Following Receiver-Operating-Characteristics (ROC) analysis, individual milk samples were assessed with the cut-off value 0.573, previously shown to be associated with each 100% sensitivity and specificity. In addition, the present study enabled BTM cut-off adjustment based on field data. To ensure reliable detection of herds with an in-herd prevalence of ≥20% the BTM cut-off was lowered from 0.493 to 0.410, corresponding to 100% sensitivity and 97.32% specificity. Regression analysis showed that the percentage of seropositive animals related to the corresponding BTM ODR correlated moderately ( r  = 0.581, P r  = 0.764, P In addition to the knowledge gained on antibody patterns in dairy herds and the relationship of individual and BTM, the present study enabled sensitivity and specificity calculations for the obsolete BTM cut-off value 0.493 to be performed.

  • a survey on Dictyocaulus viviparus antibodies in bulk milk of dairy herds in northern germany
    Preventive Veterinary Medicine, 2012
    Co-Authors: Annemarie Klewer, Thomas Schnieder, A. B. Forbes, Christina Strube
    Abstract:

    Parasitic bronchitis caused by the bovine lungworm, Dictyocaulus viviparus, occurs worldwide in temperate areas. The parasite is found predominantly in calves and heifers, but dairy cattle can suffer from lungworms when they become infected for the first time or if they have lost immunity due to lack of exposure to lungworm larvae during the grazing season. The present study was performed to determine the D. viviparus bulk milk antibody prevalence in dairy herds in the East Frisian region of northwestern Germany, Lower Saxony, by analysing bulk milk samples collected in January (860 samples), September (866 samples) and November (860 samples) 2008, thereby representing 906 dairy farms. These samples were tested for antibodies against D. viviparus by a milk ELISA. This test detects patent infections only since it is based on recombinant major sperm protein as antigen. While in January 12.8% of dairy farms were positive for D. viviparus antibodies, the bulk milk samples collected in September and November revealed 6.9% and 6.6% positive dairy herds. From the 906 dairy farms included in the study, 191 (21.1%) tested positive at least once for antibodies against lungworm. From 810 dairy farms from which bulk milk samples were obtained during all three samplings, 146 (18.0%) farms were positive at one sampling date, 27 (3.3%) at two, and 4 (0.5%) on all three sampling dates. The majority of the farms represented in the study belonged to four districts of East Frisia, which showed no significant difference in the proportion of positive dairy farms.

  • gtp cyclohydrolase and development in teladorsagia circumcincta and Dictyocaulus viviparus nematoda strongylida
    Experimental Parasitology, 2011
    Co-Authors: Rachael H Baker, Sandra Buschbaum, Thomas Schnieder, Christina Strube, Jacqueline B Matthews, Iain J Mckendrick, Alasdair J Nisbet
    Abstract:

    Abstract GTP-Cyclohydrolase (GTP-CH) is necessary for the production of tetrahydrobiopterin, a required cofactor for the three aromatic amino acid hydroxylases and nitric oxide synthases. The gene encoding GTP-CH is transcribed at high levels in infective third larval stages of a number of parasitic trichostrongylid nematodes. We explore the potential role of GTP-CH within the processes of nematode development and environmentally-induced hypobiosis. For two species of parasitic nematode that are of major economic and welfare importance to livestock in temperate regions, Teladorsagia circumcincta and Dictyocaulus viviparus, we have demonstrated that each of the pre-parasitic larval stages transcribe high mean levels of cat-4 (the gene encoding GTP-CH). Using quantitative real-time polymerase chain reaction analysis and two different isolates of D. viviparus, only one of which is capable of entering hypobiosis, we have shown that there were only minor differences between these isolates in mean cat-4 transcript levels, both during the parasitic stages and during the earlier environmental life cycle stages (L1–L3). Taken together, these data indicate that, although both species of nematode produce high levels of cat-4 transcript in pre-parasitic larval stages, GTP-CH levels are unlikely to be involved in the induction of parasite hypobiosis. Alternative roles for GTP-CH in larval development are discussed.

  • deep insights into Dictyocaulus viviparus transcriptomes provides unique prospects for new drug targets and disease intervention
    Biotechnology Advances, 2011
    Co-Authors: Cinzia Cantacessi, Neil D Young, Thomas Schnieder, Christina Strube, Shoba Ranganathan, Robin B Gasser, Aaron R Jex, Ross S Hall, Bronwyn E Campbell, Paul W Sternberg
    Abstract:

    The lungworm, Dictyocaulus viviparus, causes parasitic bronchitis in cattle, and is responsible for substantial economic losses in temperate regions of the world. Here, we undertake the first large-scale exploration of available transcriptomic data for this lungworm, examine differences in transcription between different stages/both genders and identify and prioritize essential molecules linked to fundamental metabolic pathways, which could represent novel drug targets. Approximately 3 million expressed sequence tags (ESTs), generated by 454 sequencing from third-stage larvae (L3s) as well as adult females and males of D. viviparus, were assembled and annotated. The assembly of these sequences yielded ~ 61,000 contigs, of which relatively large proportions encoded collagens (4.3%), ubiquitins (2.1%) and serine/threonine protein kinases (1.9%). Subtractive analysis in silico identified 6928 nucleotide sequences as being uniquely transcribed in L3, and 5203 and 7889 transcripts as being exclusive to the adult female and male, respectively. Most peptides predicted from the conceptual translations were nucleoplasmins (L3), serine/threonine protein kinases (female) and major sperm proteins (male). Additional analyses allowed the prediction of three drug target candidates, whose Caenorhabditis elegans homologues were linked to a lethal RNA interference phenotype. This detailed exploration, combined with future transcriptomic sequencing of all developmental stages of D. viviparus, will facilitate future investigations of the molecular biology of this parasitic nematode as well as genomic sequencing. These advances will underpin the discovery of new drug and/or vaccine targets, focused on biotechnological outcomes.

  • evaluation of a milk elisa for the serodiagnosis of Dictyocaulus viviparus in dairy cows
    Veterinary Parasitology, 2009
    Co-Authors: Christiane Fiedor, Sandra Buschbaum, A. B. Forbes, Christina Strube, G Von Samsonhimmelstjerna, Annemarie Klewer, Thomas Schnieder
    Abstract:

    An enzyme-linked immunosorbent assay (ELISA) for the detection of antibodies against the bovine lungworm Dictyocaulus viviparus in milk was established. This test is based on recombinant major sperm protein (MSP) as the antigen and ELISA results are expressed as optical density ratio (ODR) values. The cut-off value of the milk ELISA was determined as the arithmetic mean of negative milk samples plus three standard deviations (SD). Specificity and sensitivity were 100% and 97.5%, respectively, using either milk or serum samples as positive control to calculate the ODR. Therefore, the presented recombinant antigen-based ELISA is suitable for routine veterinary diagnosis of exposure to bovine lungworms using milk samples instead of sera. To assess the course of antibody titres following lungworm infection, milk and serum samples from experimentally infected dairy cows were collected over a period of 23-30 weeks in three trials. The milk and serum antibody titre curves showed strong Pearson correlation coefficients in all three trials (Trial 1=0.85; Trials 2 and 3=0.93). In milk D. viviparus-specific antibodies exceeded the cut-off value 30-32 days post-infection (dpi) and remained above this value until day 112-138 post-infection (pi) with an overall detection period of 79-107 days. Treatment with eprinomectin during the pre-patent period prevented larval shedding and the antibody response was eliminated; treatment during patency similarly caused a cessation of larval shedding, but had no effect on the pattern of antibody responses compared to the untreated, infected controls.

Malcolm W Kennedy - One of the best experts on this subject based on the ideXlab platform.

  • isotype specific antibody responses to the surface exposed antigens of adult and larval stages of Dictyocaulus viviparus in infected and vaccinated calves
    Veterinary Parasitology, 1996
    Co-Authors: J B Mckeand, J L Duncan, G M Urquhart, Malcolm W Kennedy
    Abstract:

    The antibody responses to the surface-exposed antigens of living larval and adult Dictyocaulus viviparus were measured by quantitative immunofluorescence using sera from calves infected with, or vaccinated against, the parasite. In infected animals, the surface of the sheath of the third-stage larvae (L3) (retained cuticle of second-stage larvae (L2)) proved highly immunogenic despite the fact that it is thought to be shed prior to parasite penetration of the host intestine. When responses to the surface of exsheathed larvae (L3 cuticle) were measured, a high level of heterophile IgM antibody was detected in the serum of animals that had not been previously exposed to the parasite and, following infection, a specific IgG response was detected against the exsheathed L3 surface. The antibody response, however, was less marked than that observed against the intact L3 sheath. Responses of patently infected animals to the adult surface showed an initial IgM response that was superseded with time by IgG1 and IgG2 responses. Vaccinated animals showed only low level responses to the surfaces of the L3 sheath, L3 cuticle and adult stages following immunisation with two doses of irradiated larvae. The immunised animals produced a strong antibody response to the larval surface antigens following challenge with infective larvae but they failed to produce antibody to the surface of adult parasites. These results show that the surfaces of all the stages of D. viviparus examined are immunogenic in infected calves and, depending on the developmental stage, infection regime, or time of infection, high levels of parasite-specific IgG1 or IgM are stimulated. It has previously been shown that significant levels of protective immunity can be obtained in naive animals following passive transfer of serum from infected calves. Thus, the antibody responses detected in the work reported here may be of relevance in protective immunity against dictyocaulosis.

  • the dva 1 polyprotein of the parasitic nematode Dictyocaulus viviparus a small helix rich lipid binding protein
    Journal of Biological Chemistry, 1995
    Co-Authors: Malcolm W Kennedy, Collette Britton, Nicholas C Price, Sharon M Kelly, Alan Cooper
    Abstract:

    DNA encoding a single unit of the DvA-1 polyprotein of the parasitic nematode Dictyocaulus viviparus was isolated and the polypeptide ("rDvA-1L") expressed in Escherichia coli, to give a protein showing high binding affinity for fatty acids and retinoids. Fluorescent fatty acid probes show substantial changes in emission spectrum in the presence of rDvA-1L, which can be reversed by fatty acids (oleic, palmitic, stearic, arachidonic) and retinoids, but not by tryptophan, squalene, or cholesterol. Moreover, changes in intrinsic fluorescence of retinol or retinoic acid confirm a retinoid binding activity. Fluorescence titration experiments indicate stoichiometric binding to a single protein site per monomer unit with affinities (Kd) in the range 3 x 10(-8) M for 11-((5-dimethylaminonaphthalene-1-sulfonyl)amino)undecanoic acid, and by competition, 5 x 10(-8) M for oleic acid. The extreme blue shift of bound fluorescent fatty acid suggests an unusually low polarity for the protein binding site. The emission spectrum of the single tryptophan of rDvA-1L indicates that it is deeply buried in a nonpolar environment, and its spectrum is unaffected by ligand binding. Far UV circular dichroism of rDvA-1L reveals a high alpha-helix content (53%). Differential scanning calorimetry studies indicate that rDvA-1L is highly stable (T(m) approximately 98 degrees C), refolding efficiently following thermal denaturation. DvA-1 therefore represents an example of a new class of lipid binding protein, and is the first product of a polyprotein with this activity to be described.

  • immunisation of guinea pigs against Dictyocaulus viviparus using adult es products enriched for acetylcholinesterases
    International Journal for Parasitology, 1995
    Co-Authors: J B Mckeand, D P Knox, J L Duncan, Malcolm W Kennedy
    Abstract:

    Abstract The adult ES products of Dictyocaulus viviparus are a source of protective antigens against challenge in the guinea pig laboratory model. High levels of acetylcholinesterase (AChE) activity are present in these products and these enzymes are immunogenic in infected cattle. Here, the potential role of these enzymes in protective immunity was investigated using a fraction enriched for AChE to immunise guinea pigs. The antibody response stimulated by immunisation with AChE-enriched ES products and the worm burdens obtained following challenge with infective larvae were compared with those in animals immunised with whole ES products and challenge controls. The AChE-enriched preparation stimulated high levels of enzyme-specific antibody in immunised animals, which was not the case for those which received unfractionated ES products. Worm burdens of guinea pigs which received the AChE-enriched fraction were significantly lower than those obtained in adjuvant controls. The animals which received the unfractionated ES products were not significantly protected against challenge. These results suggest that AChEs may be potential candidates for incorporation in a sub-unit vaccine against D. viviparus .

  • extensive diversity in repeat unit sequences of the cdna encoding the polyprotein antigen allergen from the bovine lungworm Dictyocaulus viviparus
    Molecular and Biochemical Parasitology, 1995
    Co-Authors: Collette Britton, John S Gilleard, Joyce Moore, Malcolm W Kennedy
    Abstract:

    The complete sequence of the cDNA encoding the nematode polyprotein allergen/antigen (NPA) of the bovine lungworm Dictyocaulus viviparus was obtained by immunoscreening of cDNA expression libraries and by 5′ RACE (rapid amplification of cDNA ends). The encoded polypeptide is similar in sequence to the ABA-1 allergen of Ascaris, the gp15/400 ‘ladder’ protein of Brugia malayi, Brugia pahangi and Wuchereria bancrofti, and a 15-kDa antigen of Dirofilaria immitis. As with these, the predicted amino-acid sequence comprises a head-to-tail array of similar polypeptides with regularly spaced consensus proteinase cleavage sites. The D. viviparus protein was designated DvA-1 (D. viviparus antigen-1) and the gene dva-1. The deduced amino-acid sequence of DvA-1 showed features not observed before in other NPAs: (i) a hydrophobic leader peptide is present, (ii) none of the 12 units in the array are indentical and the sequences diverge to a degree hitherto unseen in the NPAs of other nematode parasites, (iii) the predicted proteinase cleavage sites are also diverse in sequence and, in two instances, no consensus cleavage site was identifiable at the expected position, (iv) a short repeat unit is present, which is the only one containing a consensus N-glycosylation site and (v) a C-terminal extension peptide is encoded which shows no similarity to that from A. suum ABA-1. Comparison of independent cDNAs revealed slight variations in the sequence of the gene within the parasite population. Antisera to recombinant DvA-1 polypeptide identified 14–15-kDa antigens in both parasite somatic and excretory-secretory material. DvA-1 is the only NPA for which the complete coding sequence is available and the new principles which it illustrates may lie unsuspected in the NPA-encoding genes of all nematode parasites.

  • protective immunisation of guinea pigs against Dictyocaulus viviparus using excretory secretory products of adult parasites
    International Journal for Parasitology, 1995
    Co-Authors: J B Mckeand, D P Knox, J L Duncan, Malcolm W Kennedy
    Abstract:

    Abstract Parasite preparations were examined for their ability to induce protective immunity against Dictyocaulus viviparus in guinea pigs. Dunkin-Hartley strain guinea pigs were immunised with somatic extracts of adult parasites, somatic extracts of third stage larvae or excretory/secretory (ES) products from adult parasites. The groups were immunised twice with Freund's adjuvant four weeks apart and challenged with 6000 infective L3. Significant levels of protective immunity were observed only in the adult ES-immunised animals. The antibody responses of the different groups were compared following analysis by ELISA and immunoprecipitation. To examine the protective role of antibody, guinea pigs were passively immunised with serum from animals immunised with adult ES products or serum from guinea pigs exposed to experimental D. viviparus infection. Following challenge with infective L3, lungworm burdens of these groups were significantly lower than in guinea pigs which received normal sera. The results suggest that D. viviparus adult ES products contain protective antigens and that antibody-mediated mechanisms contribute to immune protection.

A. B. Forbes - One of the best experts on this subject based on the ideXlab platform.

  • serological lessons from the bovine lungworm Dictyocaulus viviparus antibody titre development is independent of the infection dose and reinfection shortens seropositivity
    Veterinary Parasitology, 2017
    Co-Authors: Christina Strube, Andrea Springer, Annemarie Schunn, A. B. Forbes
    Abstract:

    Infections with the bovine lungworm Dictyocaulus viviparus, the causative agent of parasitic bronchitis, are accompanied by substantial economic losses due to impacts on production, clinical respiratory disease or even death of diseased cattle. To detect lungworm antibodies in cattle, an enzyme-linked immunosorbent assay (ELISA) based on recombinant major sperm protein (MSP) has been developed. However, it remained unknown whether the infection dose influences antibody levels, and how acquired immunity influences antibody level patterns during reinfections. The latter may lead to low within-herd seroprevalence and thus to negative MSP-ELISA results in examination of bulk tank milk (BTM). Thus, infection experiments with 12 different doses ranging from 10 to 3000 D. viviparus larvae were performed to assess whether the antibody response is dose-dependent. Second, the impact of reinfections on the antibody response was evaluated in infection experiments, and third, antibody patterns in dairy cows during naturally occurring reinfections were assessed in a longitudinal field study based on individual milk samples. Results of this study demonstrate that the rise in MSP antibodies during first infection is dose-independent at infection doses of 25 lungworm larvae and above. However, following reinfections the magnitude and duration of the MSP antibody response are reduced or lacking, depending on the interval to reinfection. The field study revealed short periods of seropositivity as a common pattern in dairy cows subjected to natural D. viviparus reinfections. Low within-herd seroprevalence in dairy herds can thus be a result of continuous reinfections. Low infection doses should not be a barrier to serodiagnosis of lungworm infection in first-time infected cattle.

  • prevalence and seasonality of bulk milk antibodies against Dictyocaulus viviparus and ostertagia ostertagi in irish pasture based dairy herds
    Veterinary Parasitology, 2015
    Co-Authors: Yris Bloemhoff, Grace Mulcahy, Eric R Morgan, A. B. Forbes, Barbara Good, Riona Sayers
    Abstract:

    Infections with Dictyocaulus viviparus and Ostertagia ostertagi nematode parasites are of importance to bovine health and production in temperate areas across the world. Losses due to these parasites in dairy herds can be considerable due to decreased milk productivity and fertility. However, information on current epidemiological patterns in Irish dairy herds is limited. Bulk milk samples were collected from a total of 319 dairy farms across the Republic of Ireland. The D. viviparus samples were tested with an ELISA based on recombinant major sperm protein, while the O. ostertagi samples were tested with an ELISA based on crude saline extract, whole worm O. ostertagi antigen. Management data were collected from the farms using a questionnaire. Logistic regression was used to find significant associations between the presence of antibodies against D. viviparus and O. ostertagi and management factors. The overall prevalence of D. viviparus infection was 62.8%, while over 98% of herds had antibodies to O. ostertagi at the specified cut-off. Both D. viviparus and O. ostertagi antibodies were highest in November, which could be explained by the accumulated uptake of larvae through the grazing season. In herds of farmers that dosed their in-calf heifers with anthelmintics were significantly more likely to be positive for antibodies against D. viviparus infection. This study highlights that both D. viviparus and O. ostertagi infections are widespread in dairy herds in Ireland throughout the grazing season.

  • validation of a Dictyocaulus viviparus msp elisa and cut off adjustment in a one year longitudinal field study in dairy cattle herds
    Veterinary Parasitology, 2012
    Co-Authors: Annemarie Schunn, Thomas Schnieder, A. B. Forbes, Christina Strube
    Abstract:

    Abstract A one-year field study analysing lungworm seropositivity by use of the MSP-ELISA was performed (1) to investigate the antibody dynamics in individual milk samples following field (re-)infections of dairy cows with the bovine lungworm Dictyocaulus viviparus , (2) to investigate the correlation between individual and bulk tank milk (BTM) antibody titres and (3) to review the current individual as well as BTM cut-off value, which was extrapolated from dilution experiments ( Fiedor et al., 2009 ). Over a one-year period individual and BTM samples were collected monthly on 15 dairy farms. Following a critical review of previous cut-off values, individual and BTM samples were subjected to different cut-off thresholds. Following Receiver-Operating-Characteristics (ROC) analysis, individual milk samples were assessed with the cut-off value 0.573, previously shown to be associated with each 100% sensitivity and specificity. In addition, the present study enabled BTM cut-off adjustment based on field data. To ensure reliable detection of herds with an in-herd prevalence of ≥20% the BTM cut-off was lowered from 0.493 to 0.410, corresponding to 100% sensitivity and 97.32% specificity. Regression analysis showed that the percentage of seropositive animals related to the corresponding BTM ODR correlated moderately ( r  = 0.581, P r  = 0.764, P In addition to the knowledge gained on antibody patterns in dairy herds and the relationship of individual and BTM, the present study enabled sensitivity and specificity calculations for the obsolete BTM cut-off value 0.493 to be performed.

  • a survey on Dictyocaulus viviparus antibodies in bulk milk of dairy herds in northern germany
    Preventive Veterinary Medicine, 2012
    Co-Authors: Annemarie Klewer, Thomas Schnieder, A. B. Forbes, Christina Strube
    Abstract:

    Parasitic bronchitis caused by the bovine lungworm, Dictyocaulus viviparus, occurs worldwide in temperate areas. The parasite is found predominantly in calves and heifers, but dairy cattle can suffer from lungworms when they become infected for the first time or if they have lost immunity due to lack of exposure to lungworm larvae during the grazing season. The present study was performed to determine the D. viviparus bulk milk antibody prevalence in dairy herds in the East Frisian region of northwestern Germany, Lower Saxony, by analysing bulk milk samples collected in January (860 samples), September (866 samples) and November (860 samples) 2008, thereby representing 906 dairy farms. These samples were tested for antibodies against D. viviparus by a milk ELISA. This test detects patent infections only since it is based on recombinant major sperm protein as antigen. While in January 12.8% of dairy farms were positive for D. viviparus antibodies, the bulk milk samples collected in September and November revealed 6.9% and 6.6% positive dairy herds. From the 906 dairy farms included in the study, 191 (21.1%) tested positive at least once for antibodies against lungworm. From 810 dairy farms from which bulk milk samples were obtained during all three samplings, 146 (18.0%) farms were positive at one sampling date, 27 (3.3%) at two, and 4 (0.5%) on all three sampling dates. The majority of the farms represented in the study belonged to four districts of East Frisia, which showed no significant difference in the proportion of positive dairy farms.

  • evaluation of a milk elisa for the serodiagnosis of Dictyocaulus viviparus in dairy cows
    Veterinary Parasitology, 2009
    Co-Authors: Christiane Fiedor, Sandra Buschbaum, A. B. Forbes, Christina Strube, G Von Samsonhimmelstjerna, Annemarie Klewer, Thomas Schnieder
    Abstract:

    An enzyme-linked immunosorbent assay (ELISA) for the detection of antibodies against the bovine lungworm Dictyocaulus viviparus in milk was established. This test is based on recombinant major sperm protein (MSP) as the antigen and ELISA results are expressed as optical density ratio (ODR) values. The cut-off value of the milk ELISA was determined as the arithmetic mean of negative milk samples plus three standard deviations (SD). Specificity and sensitivity were 100% and 97.5%, respectively, using either milk or serum samples as positive control to calculate the ODR. Therefore, the presented recombinant antigen-based ELISA is suitable for routine veterinary diagnosis of exposure to bovine lungworms using milk samples instead of sera. To assess the course of antibody titres following lungworm infection, milk and serum samples from experimentally infected dairy cows were collected over a period of 23-30 weeks in three trials. The milk and serum antibody titre curves showed strong Pearson correlation coefficients in all three trials (Trial 1=0.85; Trials 2 and 3=0.93). In milk D. viviparus-specific antibodies exceeded the cut-off value 30-32 days post-infection (dpi) and remained above this value until day 112-138 post-infection (pi) with an overall detection period of 79-107 days. Treatment with eprinomectin during the pre-patent period prevented larval shedding and the antibody response was eliminated; treatment during patency similarly caused a cessation of larval shedding, but had no effect on the pattern of antibody responses compared to the untreated, infected controls.

J B Mckeand - One of the best experts on this subject based on the ideXlab platform.

  • isotype specific antibody responses to the surface exposed antigens of adult and larval stages of Dictyocaulus viviparus in infected and vaccinated calves
    Veterinary Parasitology, 1996
    Co-Authors: J B Mckeand, J L Duncan, G M Urquhart, Malcolm W Kennedy
    Abstract:

    The antibody responses to the surface-exposed antigens of living larval and adult Dictyocaulus viviparus were measured by quantitative immunofluorescence using sera from calves infected with, or vaccinated against, the parasite. In infected animals, the surface of the sheath of the third-stage larvae (L3) (retained cuticle of second-stage larvae (L2)) proved highly immunogenic despite the fact that it is thought to be shed prior to parasite penetration of the host intestine. When responses to the surface of exsheathed larvae (L3 cuticle) were measured, a high level of heterophile IgM antibody was detected in the serum of animals that had not been previously exposed to the parasite and, following infection, a specific IgG response was detected against the exsheathed L3 surface. The antibody response, however, was less marked than that observed against the intact L3 sheath. Responses of patently infected animals to the adult surface showed an initial IgM response that was superseded with time by IgG1 and IgG2 responses. Vaccinated animals showed only low level responses to the surfaces of the L3 sheath, L3 cuticle and adult stages following immunisation with two doses of irradiated larvae. The immunised animals produced a strong antibody response to the larval surface antigens following challenge with infective larvae but they failed to produce antibody to the surface of adult parasites. These results show that the surfaces of all the stages of D. viviparus examined are immunogenic in infected calves and, depending on the developmental stage, infection regime, or time of infection, high levels of parasite-specific IgG1 or IgM are stimulated. It has previously been shown that significant levels of protective immunity can be obtained in naive animals following passive transfer of serum from infected calves. Thus, the antibody responses detected in the work reported here may be of relevance in protective immunity against dictyocaulosis.

  • immunisation of guinea pigs against Dictyocaulus viviparus using adult es products enriched for acetylcholinesterases
    International Journal for Parasitology, 1995
    Co-Authors: J B Mckeand, D P Knox, J L Duncan, Malcolm W Kennedy
    Abstract:

    Abstract The adult ES products of Dictyocaulus viviparus are a source of protective antigens against challenge in the guinea pig laboratory model. High levels of acetylcholinesterase (AChE) activity are present in these products and these enzymes are immunogenic in infected cattle. Here, the potential role of these enzymes in protective immunity was investigated using a fraction enriched for AChE to immunise guinea pigs. The antibody response stimulated by immunisation with AChE-enriched ES products and the worm burdens obtained following challenge with infective larvae were compared with those in animals immunised with whole ES products and challenge controls. The AChE-enriched preparation stimulated high levels of enzyme-specific antibody in immunised animals, which was not the case for those which received unfractionated ES products. Worm burdens of guinea pigs which received the AChE-enriched fraction were significantly lower than those obtained in adjuvant controls. The animals which received the unfractionated ES products were not significantly protected against challenge. These results suggest that AChEs may be potential candidates for incorporation in a sub-unit vaccine against D. viviparus .

  • protective immunisation of guinea pigs against Dictyocaulus viviparus using excretory secretory products of adult parasites
    International Journal for Parasitology, 1995
    Co-Authors: J B Mckeand, D P Knox, J L Duncan, Malcolm W Kennedy
    Abstract:

    Abstract Parasite preparations were examined for their ability to induce protective immunity against Dictyocaulus viviparus in guinea pigs. Dunkin-Hartley strain guinea pigs were immunised with somatic extracts of adult parasites, somatic extracts of third stage larvae or excretory/secretory (ES) products from adult parasites. The groups were immunised twice with Freund's adjuvant four weeks apart and challenged with 6000 infective L3. Significant levels of protective immunity were observed only in the adult ES-immunised animals. The antibody responses of the different groups were compared following analysis by ELISA and immunoprecipitation. To examine the protective role of antibody, guinea pigs were passively immunised with serum from animals immunised with adult ES products or serum from guinea pigs exposed to experimental D. viviparus infection. Following challenge with infective L3, lungworm burdens of these groups were significantly lower than in guinea pigs which received normal sera. The results suggest that D. viviparus adult ES products contain protective antigens and that antibody-mediated mechanisms contribute to immune protection.

  • the immunogenicity of the acetylcholinesterases of the cattle lungworm Dictyocaulus viviparus
    International Journal for Parasitology, 1994
    Co-Authors: J B Mckeand, D P Knox, J L Duncan, Malcolm W Kennedy
    Abstract:

    Somatic extracts and excretory/secretory (ES) products of the adult stage of the cattle nematode, Dictyocaulus viviparus, were examined for acetylcholinesterase (AChE) activity. Both were found to contain activity which had an optimum pH of 9.5, however, the adult ES products contained over 200 times more AChE activity per unit protein. Gel electrophoresis and specific enzyme staining revealed 5 migratory isoforms of AChE which were common to adult ES products and adult homogenates. Comparison of L3 with L4 and adult extracts indicated that the AChE were only produced by later developmental stages of this parasite. The antigenicity of D. viviparus AChE was demonstrated by binding to serum IgG from naturally and experimentally infected calves but the enzymes were not recognized by calves vaccinated twice with 400 Gy-irradiated larvae. This is the first report of helminth AChE release by a parasitic nematode in a pulmonary location. The presence of these enzymes in such high amounts in the ES products, along with their immunogenicity, suggests that they might have an important role to play in the immunobiology of D. viviparus in the lungs.

  • genetic control of the antibody repertoire against excretory secretory products and acetylcholinesterases of Dictyocaulus viviparus
    Parasite Immunology, 1994
    Co-Authors: J B Mckeand, D P Knox, J L Duncan, Malcolm W Kennedy
    Abstract:

    SUMMARY Outbred Dunkin-Hartley and inbred strain 2 and strain 13 guinea pigs were immunized with Dictyocaulus viviparus adult ES products prior to challenge with third stage larvae. Antibody responses of the three strains to adult ES products and the acetylcholinesterase (AChE) isoforms which they contain were examined. Using immunoprecipitation and ELISA, it was observed that responses in the three strains to adult ES products were distinct: considerable heterogeneity in the antibody repertoire was observed between outbred Dunkin-Hartley animals, with only slight variation occurring amongst the inbred individuals. Responses to the AChE isoforms were heterogeneous amongst individual outbred guinea pigs but were more consistent in inbred strain 2 and 13 animals in which strain-specific patterns of recognition were observed. Previous studies with nematode infections have indicated a role for the major histocompatibility complex in determining the nature and level of the immune response. As the inbred strains bear different alleles at the Class II region but are identical at the Class I region, the differences observed are likely to be due to genes mapping to the Class II locus. This is therefore the first report of genetic restriction of the antibody repertoire to secreted AChEs of a parasitic nematode.