Abstract
BackgroundFree-ranging chickens are often infected with Toxoplasma gondii and seroconvert upon infection. This indicates environmental contamination with T. gondii.MethodsHere, we established a bead-based multiplex assay (BBMA) using the Luminex technology for the detection of T. gondii infections in chickens. Recombinant biotinylated T. gondii surface antigen 1 (TgSAG1bio) bound to streptavidin-conjugated magnetic Luminex beads served as antigen. Serum antibodies were detected by a fluorophore-coupled secondary antibody. Beads of differing color codes were conjugated with anti-chicken IgY or chicken serum albumin and served for each sample as an internal positive or negative control, respectively. The assay was validated with sera from experimentally and naturally infected chickens. The results were compared to those from reference methods, including other serological tests, PCRs and bioassay in mice.ResultsIn experimentally infected chickens, the vast majority (98.5%, n = 65/66) of birds tested seropositive in the BBMA. This included all chickens positive by magnetic-capture PCR (100%, n = 45/45). Most, but not all inoculated and TgSAG1bio-BBMA-positive chickens were also positive in two previously established TgSAG1-ELISAs (TgSAG1-ELISASL, n = 61/65; or TgSAG1-ELISASH, n = 60/65), or positive in an immunofluorescence assay (IFAT, n = 64/65) and in a modified agglutination test (MAT, n = 61/65). All non-inoculated control animals (n = 28/28, 100%) tested negative. In naturally exposed chickens, the TgSAG1bio-BBMA showed a high sensitivity (98.5%; 95% confidence interval, CI: 90.7–99.9%) and specificity (100%; 95% CI: 85.0–100%) relative to a reference standard established using ELISA, IFAT and MAT. Almost all naturally exposed chickens that were positive in bioassay or by PCR tested positive in the TgSAG1bio-BBMA (93.5%; 95% CI: 77.1–98.9%), while all bioassay- or PCR-negative chickens remained negative (100%; 95% CI: 85.0–100%).ConclusionsThe TgSAG1bio-BBMA represents a suitable method for the detection of T. gondii infections in chickens with high sensitivity and specificity, which is comparable or even superior to other tests. Since assays based on this methodology allow for the simultaneous analysis of a single biological sample with respect to multiple analytes, the described assay may represent a component in future multiplex assays for broad serological monitoring of poultry and other farm animals for various pathogens.
Highlights
Free-ranging chickens are often infected with Toxoplasma gondii and seroconvert upon infection
Our results show that the T gSAG1bio-bead-based multiplex assay (BBMA) assay represents a suitable method with high sensitivity and specificity for the detection of T. gondii infections in chickens
Based on the promising results obtained with the BBMA using human sera and the strong performance of TgSAG1bio [37, 39], we strived for a transfer of this assay to animal species, including chickens, to establish an improved method for large scale, efficient serological monitoring
Summary
Free-ranging chickens are often infected with Toxoplasma gondii and seroconvert upon infection. This indicates environmental contamination with T. gondii. Humans acquire toxoplasmosis either congenitally or postnatally [5]. Toxoplasma gondii can be transmitted congenitally from a recently infected mother to the fetus and may cause severe disease in children (e.g. hydrocephalus, seizures, mental or growth retardation) or even abortion. A large number of ocular uveitis cases in humans seem to be caused by postnatal T. gondii infections [6]. Postnatally acquired T. gondii infections, either through consumption of undercooked infected meat or by oral uptake of oocysts shed by felids, have no severe consequences [7]. Persistent or recently acquired infections in immuno-compromised patients (e.g. transplant patients) may cause life-threatening disease [7]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
