Rapid Immunochromatographic Assay Research Articles

Detection and quantification of residues in sheep exposed to trace levels of dietary zilpaterol HCl

ABSTRACTStudy objectives were to determine zilpaterol residues in urine and tissues of sheep fed dietary zilpaterol HCl, at levels commensurate with feed contamination, using common and novel screening and quantitative analytical methods. Sheep (50.0 ± 2.7 kg) were offered feed (1.75 kg/d) containing 0.0075 (L), 0.075 (M), or 0.75 (H) mg kg−1 of zilpaterol for 12 days and were slaughtered with 0-day (L-0, M-0, H-0; n = 4 each) or 3-day (H-3; n = 4) withdrawal periods. Rapid immunochromatographic assays (ICA) consistently detected urinary zilpaterol (LOD = 1.7 ng mL−1) in L-0 (54.2%), M-0 (96.0%), and the H-0 (100%) treatment groups but only detected zilpaterol in tissues (LOD ~2.4 ng g−1) from the H-0 group. Advanced MS-based technologies detected zilpaterol in some, but not all, tissues of M-0, H-0, L-0, and H-3 sheep. Analytical techniques commonly used to ensure compliance with show-animal rules, import/export guidelines, and regulatory statutes routinely detected residues in animals exposed to zilpaterol at doses insufficient to elicit growth responses.

Peptide Aptamer of Complementarity-determining Region to Detect Avian Influenza Virus.

Despite significant progress in the development of diagnostic methods for influenza, avian influenza (AI) infection continues to represent a substantial threat to human health. Among the subtypes of AI, H5 influenza is highly infectious to animals and humans; however, there are no reliable H5 subtype-specific diagnostic systems owing to a scarcity of H5 subtype-specific detection elements. In this study, a new peptide aptamer (P1:KASGYTFTSF) was developed to recognize the H5 viral subtype using an in silico bioinformatics approach for predicting complementarity-determining regions (CDRs), and the aptamer was evaluated by immunoassays. The three-dimensional structure of influenza hemagglutinin (HA) and the peptide were used in a molecular docking study, and the peptide was compared to the epitope-derived peptide aptamer (H5-P2:KPNGAINF). Interactions between the peptides and the virus were then assessed by fluorescence-linked sandwich immunosorbent assay (FLISA), immunofluorescence staining assay (IFA), and rapid fluorescent immunochromatographic assay (FICT). P1 and H5-P2 both significantly detected H5N3 at 15.6 HAU/mL (P < 0.05), and P1 detected the virus more effectively (P < 0.05), consistent with the docking result. An optical image of the peptide recognizing an H5N3-infected cell was acquired by IFA, and was consistent with the antibody-linked IFA result. FICT employing the peptide showed the ability for H5 subtype-specific diagnosis, with 2-fold higher performance than that of a conventional, antibody-linked rapid test. This work shows the potential of a CDR-predicted peptide aptamer as a probe for immunological assays that can specifically recognize AI virus.

Development and application of monoclonal antibodies anti-human lipoprotein-associated phospholipase A2

The aim of this study is to prepare monoclonal anti-human Lp-PLA2 antibodies, and establish a rapid and accurate immunochromatographic Lp-PLA2 assay used in community medical institution. The gene sequence of human Lp-PLA2 was obtained from NCBI to construct the expression plasmid. Lp-PLA2 protein expressed in CHO-K1 cells was used to immune BALB/c mice. The monoclonal antibodies were produced in mouse ascites after hybridoma cells screening. Antibodies were evaluated by SDS-PAGE, ELISA and other methods. The Lp-PLA2 test strip was prepared based on sandwich method and evaluated with the portable detection instrument. The affinity of the paired antibodies, PLA1 and PLA5, both reached 1×10⁻⁸. The antibody subclass was IgG1. Both antibodies recognized the Lp-PLA2 protein in the blood specifically. The Lp-PLA2 test strip was prepared based on sandwich method, with linear range of 20-2000 ng/mL. The Lp-PLA2 test strip correlated well with the diaDexus ELISA test kit. In conclusion, the paired antibodies were successfully prepared with high affinity and specificity. The immunochromatographic test of Lp-PLA2 provided a fast and accurate method to detect the concentration of Lp-PLA2 in blood sample for clinical use in the community medical institution and could contribute to the management of cardiovascular diseases.

Evaluation of a Rapid Immunochromatographic Assay and Two Enzyme-Linked Immunosorbent Assays for Detection of IgM-Class Antibodies to Zika Virus.

There are currently five serologic assays available for detection of anti-Zika virus (ZIKV) IgM-class antibodies with U.S. Food and Drug Administration emergency use authorization. Among these are the Chembio DPP Zika IgM system (DPP Zika ICA; Chembio, Medford, NY), a rapid immunochromatographic assay (ICA), and the InBios ZIKV Detect 2.0 IgM antibody capture enzyme-linked immunosorbent assay (ZIKV 2.0 MAC-ELISA; InBios international, Inc., Seattle, WA), which has replaced the original InBios ZIKV Detect MAC-ELISA. We evaluated performance of these three serologic assays using 72 specimens characterized by plaque reduction neutralization testing (PRNT) for the presence or absence of neutralizing antibodies (NAbs) to ZIKV, dengue virus (DENV), and West Nile virus (WNV). The InBios ZIKV 2.0 MAC-ELISA was "presumptive Zika positive" in all 15 PRNT-confirmed ZIKV samples, while the Chembio DPP Zika ICA was nonreactive in three (20%) and the InBios ZIKV MAC-ELISA was negative in four (27%). The Chembio DPP Zika ICA and InBios ZIKV 2.0 MAC-ELISA showed >95% specificity in 22 ZIKV/DENV-seronegative specimens and in 13 samples positive for NAbs to non-ZIKV flaviviruses. Comparatively, the InBios ZIKV MAC-ELISA was "presumptive" or "possible Zika positive" in 8 of 12 WNV or DENV PRNT-positive samples and in 12 of 22 PRNT-seronegative sera. Our findings suggest that replacement of the InBios ZIKV MAC-ELISA with the InBios ZIKV 2.0 MAC-ELISA will lead to fewer samples requiring PRNT, minimizing unnecessary anxiety among patients ultimately determined to be seronegative for ZIKV and DENV by PRNT and alleviating some of the testing burden on laboratories performing PRNT.

Development of a multicomponent immunochromatographic test system for the detection of fluoroquinolone and amphenicol antibiotics in dairy products

Ciprofloxacin (CIP) and chloramphenicol (CAP) are relevant antibiotics of the fluoroquinolone (FQ) and amphenicol (AP) groups, respectively, widely used in veterinary practice and they contaminate agricultural products. In this study, a rapid and sensitive immunochromatographic assay (ICA) was developed for simultaneous detection of CIP and CAP in dairy products. The ICA was carried out in a direct competitive format using gold nanoparticles as a label. The ICA developed here allowed for the detection of CIP and CAP in Triton X-100-containing buffered saline (PBST) within 15 min with instrumental detection limits of 20 pg mL-1 and 0.5ng mL-1 , respectively, and with a visual detection limit of 5ng mL-1 for both antibiotics. The ICA showed cross-reactivity (69-160%) to 19 antibiotics in the FQ group and no cross-reactivity (<0.1%) to 2 antibiotics of the AP group. The ICA allowed detection of CIP and CAP in a panel of dairy products by employing a simple procedure of preliminary sample preparation. The detection limits for the two antibiotics were the same as in PBST. The analytical recoveries of CIP and CAP in dairy products ranged from 83% to 120%. The analytical characteristics of the test system allow its use for the detection of antibiotics in milk and dairy products during all steps of production. © 2019 Society of Chemical Industry.

Upconversion luminescence nanoparticles-based immunochromatographic assay for quantitative detection of triamcinolone acetonide in cosmetics

Triamcinolone acetonide (TCA) abuse in cosmetics is a common phenomenon. A rapid lateral flow immunochromatographic assay (ICA) was developed for the quantitative detection of TCA using a probe based on upconversion luminescence nanoparticles. Lanthanide-doped upconversion nanoparticles (UCNPs) were synthesized in a system comprising water and ethylene glycol, and a silicon dioxide layer was covered at the carboxyl site. A binding site protection strategy was used to decrease the background signal of UCNPs-ICA. Using dexamethasone derivative as a coating antigen, the optimal UCNPs-ICA exhibits good dynamic linear detection for TCA in the range 1.0-100 ng mL-1 with a median inhibitory concentration of 9.8 ng mL-1. The detection limits for TCA in a cosmetic sample are 20 μg kg-1. The pretreatment of samples only needs dilution with water, suggesting the assay can quantitate TCA on-site using a portable upconversion luminescence reader with a cumulative analysis time of only 10 min.

Up-Converting Nanoparticle-Based Immunochromatographic Strip for Multi-Residue Detection of Three Organophosphorus Pesticides in Food.

Organophosphorus (OP) pesticides are widely used to control pests because of their high activity. This study described a rapid and sensitive lateral flow immunochromatographic (LFIC) assay based on up-converting nanoparticles (UCNPs) for multi-residue detection of three OP pesticides. The developed assay integrated novel fluorescent material UCNPs labeled with a broad-specific monoclonal antibody. Based on the competitive platform by immobilized antigen in the test zone, the optimized UCNPs-LFIC assay enabled sensitive detection for parathion, parathion-methyl, and fenitrothion with IC50 of 3.44, 3.98, and 12.49 ng/mL (R2 ≥ 0.9776) within 40 min. The detectable ability ranged from 0.98 to 250 ng/mL. There was no cross-reactivity with fenthion, phoxim, isocarbophos, chlorpyrifos, or triazophos, even at a high concentration of 500 ng/mL. Matrix interference from various agricultural products was also studied in food sample detection. In the spiked test, recoveries of the three OP pesticides ranged from 67 to 120% and relative standard deviations were below 19.54%. These results indicated that the proposed strip assay can be an alternative screening tool for rapid detection of the three OP pesticides in food samples.

THE ROLE OF OXIDATIVE STRESS MARKERS IN Î’-THALASSEMIC IRAQI PATIENTS INFECTED WITH HEPATITIS C VIRUS DIAGNOSED BY RT-PCR

Blood transfusion is associated with the risk of infection, especially hepatitis C virus and may lead to peroxidative tissue injury by secondary iron overload in β- thalassemic patients. This study aims to detect HCV-RNA copies in thalassemic patients detected by RT-PCR qualitatively and quantitatively. Also, to measure the role of enzymatic and non-enzymatic anti-oxidants markers in β-thalassemia patients infected with HCV. A total of 200 β-thalassemic patients were collected and analyzed for anti-HCV antibodies using Rapid immunochromatographic assay and enzyme-linked Immunosorbent assay methods. Then, the nucleic acids HCV-RNA of positive samples were extracted by modern automated technique. After that, Amplification for HCV-RNA was amplified. The vitamins C and, E in addition to GSH and GGT were also accurately detected. Out of 100 positive ELISA-anti-HCV antibodies, 72(72%) were also positive for RTPCR considering the assay threshold for the procedure was &gt;13 IU/ ml. The mean viral load in these patients was 545806 ±1009799 IU/ml (1997176 ±3802206) Copies/ml. There was an observed difference (P≤ 0.005) inactivity of TSB, GGT, Protein, Albumin in sera of HCV patients (2.87 ± 1.41, 51.1 ± 60.0 , 6.44 ±2.00 , 3.37 ±0.71) when compared with healthy subjects (0.99 ± 0.46 ; 25.2 ± 12.0 , 7.09 ±0.66 , 3.94 ±0.59) respectively while the Globulin detected evinced no significant difference (P˃ 0.005) in HCV patients (2.90±0.80) as compared with healthy subjects (3.14 ±0.42). Besides there was a significant difference (P≤ 0.005) in serum vitamin C, vitamin E and GSH, between HCV patients groups (57.2 ±46.1, 34.7±14.6, 282.4 ±150.5) and healthy subject groups (73.0 ± 18.0, 44.6 ± 15.6, 353.5± 59.37) respectively. The prevalence of HCV infection was much higher among β-thalassemic patients compared with the healthy blood donors. It is recommended to use nucleic acid based-tests for screening blood donors. The current study shows that there is no correlation between ELISA and viral load in hepatitis C virus infection. On the other hand, Real-Time PCR is a confirmatory diagnostic test and is considered as the golden test for the diagnosis and follow up of hepatitis C virus infection. The HCV infection significantly increases ALT, AST, ALP, GGT, and TSB level above the normal range while vitamins C, E, and GSH decreased considerably.

Prevalence and associated factors of Chlamydia trachomatis and Neisseria gonorrhoeae among female commercial sex workers in Hawassa City, Southern Ethiopia

BackgroundChlamydia trachomatis and Neisseria gonorrhoeae are the most common pathogens causing genital tract infections. Female commercial sex workers (FCSWs) are the key population to be affected by sexually transmitted infections (STIs). In Ethiopia, little is known about C. trachomatis and N. gonorrhoeae infections in most at risk population. Therefore, this study aimed to assess the prevalence of these bacterial STIs among FCSWs.MethodsA cross-sectional study was conducted at the confidential clinic in Hawassa City, Southern Ethiopia from January to April, 2017. A total of 338 FCSWs were selected using systematic random sampling technique and enrolled in the study. Information about socio-demography and associated factors was collected using structured questionnaires. Endocervical swab samples were also collected from the study participants and tested for C. trachomatis using rapid immunochromatography assay. Samples were also cultured to isolate N. gonorrhoeae according to the standard bacteriological method.ResultsThe prevalence of N. gonorrhoeae and C. trachomatis among FCSWs was 3.3% [95% confidence interval (CI): 1.5–5.3] and 6.8% (95% CI: 3.9–9.5), respectively. FCSWs who consistently practiced sex without condom in the last 6 months had 6.3 times (AOR 6.3; 95% CI 1.61–24.86, P = 0.008), and 4.0 times (AOR 4.0; 95% CI 1.06–15.31, p = 0.040) higher odds of acquiring N. gonorrhoeae and C. trachomatis infections, respectively.ConclusionThe observed rates of C. trachomatis and N. gonorrhoeae infections among FCSWs warrant the need to strengthen intervention efforts. In this regard, screening FCSWs for the specified infections and improving the practice of condom use would be important.

Rapid detection of human blood in triatomines (kissing bugs) utilizing a lateral flow immunochromatographic assay - A pilot study.

BACKGROUND DNA- and proteomics-based techniques are currently used to identify a triatomine human blood meal. These methods are time consuming, require access to laboratories with sophisticated equipment, and trained personnel.OBJECTIVES We tested a rapid and specific immunochromatographic assay (that detects human blood in forensic samples) to determine if human blood was present in triatomines and their fecal excreta.METHODS We fed Triatoma rubida human blood (positive control) or mouse blood (negative control) and performed the assay on the abdominal contents and fecal excreta. Triatomine field specimens collected in and around human habitations and excreta were also tested.FINDINGS The assay was positive in triatomines fed human blood (N = 5/5) and fecal excreta from bugs known to have ingested human blood (N = 5/5). Bugs feeding on mice (N = 15/15) and their fecal excreta (N = 8/8) were negative for human blood. Human blood was detected in 47% (N = 23/49) triatomines, representing six different species, collected in the field.MAIN CONCLUSIONS The pilot study shows that this rapid and specific test may have applications in triatomine research. Further study is needed to determine the sensitivity of this assay compared to other well-established techniques, such as DNA- and proteomics-based methodologies and the assay’s application in the field.

Scrub typhus: An unusual cause of acute abdomen

Background: Scrub typhus is one of the causes of acute abdomen in surgical emergency. Objectives: The objective was to study the clinical profile and outcome among patients of scrub typhus presenting as acute abdomen. Materials and Methods: A community-based cross-sectional study was conducted for 15 months in eight patients who presented as acute abdominal pain with scrub typhus in a tertiary hospital. Clinical analysis, routine investigations, and rapid IgM-based immunochromatographic assay for scrub typhus are performed in every patient. Results: A total of eight females, aged ≥20 years were included in the study. Six of the patients presented with acute abdomen, two of them had features of generalized peritonitis, two had a history of loose stools, another two had a history of constipation, and one of them presented with history of bleeding per rectum. As systemic presentation, all eight patients had fever, six of the patients had nausea and vomiting, four had tachypnea, four had presented in shock, two of the patient presented with an eschar, and four had a history of headache. All patients were treated conservatively. One patient died due to multiorgan dysfunction syndrome and severe thrombocytopenia. Conclusion: Scrub typhus can rarely present as acute abdomen. High index of suspicion is required in cases of acute abdomen not responding to standard treatment.

Development of monoclonal antibody-based colloidal gold immunochromatographic assay for analysis of halofuginone in milk

ABSTRACT A highly sensitive, specific, and rapid immunochromatographic assay for halofuginone (HFG) has been developed. A well-characterized immunogenic conjugate of HFG with bovine serum albumin was produced using the N,N″-Carbonyldiimidazole method. A sensitive monoclonal antibody specific for HFG was then generated by immunizing BALB/c mic with the HFG conjugate. The antigen, HFG-CDI-ovalbumin and goat anti-mouse IgG were attached to a nitrocellulose membrane as the test line and the control line, respectively to produce an immunochromatographic test strip for the rapid detection of HFG in milk. Under optimized conditions, the detection limits of the semi-quantitative test strip for HFG were as low as 50 ng/mL in 0.01 M PBS (pH 7.4) and 100 ng/mL in milk. All the results were obtained within 5 min. The newly developed immunochromatographic assay provides a sensitive, rapid, and specific procedure for on-site screening for HFG.

METHODS OF PREVENTION OF EARLY GESTATION COMPLICATIONS IN WOMEN WITH CHRONIC GASTRITIS

Objective: to reduce the frequency of early gestational complications in pregnant women with chronic gastritis by assessing the clinical pattern of the complications, determining risk factors and prognostic criteria for their development, and introducing a two-stage prevention algorithm&#x0D; Material and methods. 160 pregnant women at 8-12 weeks of gestation were observed. They were divided into 3 groups: Group 1 – 58 pregnant women with chronic gastritis and early gestational complications; Group 2 – 62 pregnant women without chronic gastritis, but with early gestational complications; Group 3 – healthy pregnant women without chronic gastritis and gestational complications. In addition to the standard clinical and laboratory examination of patients, the levels of progesterone, estradiol and serum human chorionic gonadotropin (hCG) were determined by ELISA. H.pylory was diagnosed using a non-invasive method of rapid chromatographic immunoassay for the qualitative detection of IgG antibodies to H.pylory infection in serum. The acidity of gastric juice was determined by the level of gastrin 17 (G-17) in blood serum samples (S-G-17) using ELISA. Statistical analysis of the results was carried out using MedStat package. The mean value and the standard deviation of the parameter were calculated to present quantitative characters, and analysis of variance was used for comparison between groups. The frequency (%) was calculated to present qualitative characters. The chi-square test was used for the frequency in groups. The Bonferroni correction was used for pair comparison for three or more groups. The critical level of significance is assumed to be 0.05.&#x0D; Study results. Group 1: emesis gravidarum in 29.3%, threatened abortion in 60.3%, spontaneous miscarriage in 5.2%, missed abortion in 5.2% were diagnosed. Group 2: emesis gravidarum in 29.0%, threatened abortion in 51.6%, spontaneous miscarriage in 8.1%, missed abortion in 11.3% were diagnosed. The results of the hormonal profile study showed that in pregnant women of Group 1, the average levels of estradiol and progesterone were lower and hCG was higher than in pregnant women of Group 2, indicating a diverse change in hormonal balance that may cause early gestational complications. It is established that the frequency of emesis gravidarum, threatened abortion and spontaneous miscarriage is higher in pregnant women with chronic gastritis associated with increased basal gastric acidity with H.pylory infection. The relationship between the clinical course of gestational complications and the manifestation of chronic gastritis (vomiting, constipation) of various types, which increase the manifestations of gestational complications and determine its consequences, has been established. Based on prognostic criteria for the risk of gestational complications in pregnant women with various types of chronic gastritis, a prevention algorithm at the pregravid and gestational stages has been developed to prevent their implementation.&#x0D; Conclusion. The proposed two-step algorithm for diagnostic, therapeutic, and organizational measures provides a systematic approach to reduce early gestational complications in pregnant women with chronic gastritis.

A Multiplex Immunochromatographic Assay Employing Colored Latex Beads for Simultaneously Quantitative Detection of Four Nitrofuran Metabolites in Animal-Derived Food

A rapid and sensitive high-throughput latex bead immunochromatographic assay (LB-ICA) for simultaneously quantitative detection of four major nitrofuran metabolites, including semicarbazide (SEM), 1-aminohydantoin (AHD), 3-amino-5-methylmorpholino-2-oxazolidinone (AMOZ), and 3-amino-2-oxazolidinone (AOZ) in animal-derived food (chicken, fish, and shrimp) was developed. Four different coating antigens were separately immobilized on nitrocellulose (NC) membrane as capture reagents; red latex beads were sprayed as constant control line. Specific monoclonal antibodies labeled with blue- or red-colored latex bead reacted with analytes in standard or sample and flowed along the strip, exhibiting visible and colorful test lines after unbound antibodies coupled with corresponding antigens on four test lines. No mutual interference was found in the simultaneous detection of the four analytes even at concentrations (100 μg L−1) higher than their respective cutoff values. The limits of detection (LODs) for SEM, AHD, AMOZ, and AOZ were 0.02–0.1 μg kg−1 in chicken, 0.02–0.15 μg kg−1 in fish, and 0.03–0.12 μg kg−1 in shrimp, respectively. Recoveries ranged from 73.5 to 109.2% at fortified concentration of LOD, 2LOD, and 4LOD, with coefficient of variation < 15%. Analysis of field animal-derived food samples by LB-ICA was in accordance with that of LC-MS/MS. Therefore, this proposed multiplex LB-ICA was a promising method for on-site screening of multiple analytes in animal-derived food.

DETECTION OF RESPIRATORY SYNCYTIAL VIRUS IN INFANTS AND YOUNG CHILDREN WITH CHEST INFECTION: A COMPARISON OF REVERSE TRANSCRIPTION-PCR TECHNIQUE TO CHROMATOGRAPHIC IMMUNOASSAY AND ENZYME LINKED IMMUNOSORBENT ASSAY

Background: Human respiratory syncytial virus (hRSV) is a major cause of viral lower respiratory tract infection among infants and young children less than 2 years old. Multiple methods are used for the laboratory diagnosis of hRSV infections, including chromatographic immunoassay, enzyme linked immunosorbent assay (ELISA) and reverse transcription polymerase chain reaction (RT-PCR) technique for detection hRSV-antigens, hRSV-antibodies and hRSV-RNA, respectively. Objective: To compare the efficiency of three diagnostic methods in detection of hRSV in infants and young children with chest infection. Methods: This study included 100 hospitalized infants and young children (39 females and 61 males) aged from (1) month to (24) months, their mean age (6.87 ± 6.03) months, who required hospital admission at the Pediatric Department in Al-Imamein AL-Kadhimein Medical City Hospital, Central Teaching Pediatric Hospital, and Al-Kadhimiya Pediatric Hospital in Baghdad-Iraq. Samples were collected over a three-month winter period from January 2017 to April 2017. Fresh nasal swab specimens were collected and testes for hRSV antigens by using chromatographic immunoassay as a rapid test, in addition, nasopharyngeal/throat swabs specimens were processed for detection of hRSV-RNA by RT-PCR, both for direct detection. Also, ELISA was done to measure anti-hRSV IgM antibodies in serum for indirect detection of RSV infection. Results: hRSV was found to be positive in (27%), (56%) and (44%) of specimens by rapid chromatographic immunoassay, ELISA and RT-PCR technique, respectively. Comparing with RT-PCR, the sensitivity of rapid test was (59.09%) ranged from (44.41) to (72.31) and the specificity was (98.21%) ranged from (90.55) to (99.91) with likelihood ratio equal to (33.09), while the sensitivity of ELISA test was (75.61%) ranged from (60.66) to (86.17) and specificity was (59.62%) ranged from (46.07) to (71.84) with likelihood ratio equals to (1.87). Conclusion: The RT-PCR technique was more sensitive than antigen or antibody detection methods for the diagnosis of hRSV Keywords: hRSV, rapid chromatographic immunoassay, ELISA, RT-PCR Citation: Al-Shuwaikh AMA, Ali SH, Arif HS. Detection of respiratory syncytial virus in infants and young children with chest infection: a comparison of reverse transcription-PCR technique to chromatographic immunoassay and enzyme linked immunosorbent assay. Iraqi JMS. 2018; 16(3): 319-326. doi: 10.22578/IJMS.16.3.11

Comparing four diagnostic tests for Giardia duodenalis in dogs using latent class analysis

BackgroundTo accurately diagnose giardiosis in dogs, knowledge of diagnostic test characteristics and expected prevalence are required. The aim of this work was to estimate test characteristics (sensitivity and specificity) of four commonly used diagnostic tests for detection of Giardia duodenalis in dogs.MethodsFecal samples from 573 dogs originating from four populations (household dogs, shelter dogs, hunting dogs and clinical dogs) were examined with centrifugation sedimentation flotation (CSF) coproscopical analysis, direct immunofluorescence assay (DFA, Merifluor Cryptosporidium/Giardia®), a rapid enzyme immunochromatographic assay (IDEXX SNAP Giardia®) and qPCR (SSU rDNA) for presence of G. duodenalis. Bayesian latent class analysis was used to determine test performance characteristics and to estimate G. duodenalis prevalence of each of the four dog populations.ResultsAll tests were highly specific. IDEXX SNAP Giardia® showed the highest specificity (99.6%) and qPCR the lowest (85.6%). The sensitivities were much more variable, with qPCR showing the highest (97.0%) and CSF the lowest (48.2%) sensitivity. DFA was more sensitive than IDEXX SNAP Giardia®, but slightly less specific. Prevalences of G. duodenalis differed substantially between populations, with the hunting dogs showing the highest G. duodenalis prevalence (64.9%) and the household dogs the lowest (7.9%).ConclusionsThis study identifies qPCR as a valuable screening tool because of its high sensitivity, whereas methods using microscopy for cyst identification or cyst wall detection should be used in situations where high specificity is required. G. duodenalis is a prevalent gastro-intestinal parasite in Dutch dogs, especially in dogs living in groups (hunting and shelter dogs) and clinical dogs.

Knowledge, Serological Markers and Risk Factors associated with Hepatitis B and C Virus Infection among Kuje Prison Inmates, Federal Capital Territory, Nigeria

Background: Prisons are known to be high-risk environments for the spread of blood borne and sexually transmitted infections. Compared to the general population, prevalence of Hepatitis B and C virus (HBV/HCV) infections are disproportionately higher among penitentiary institutionalized individuals worldwide. We determined the seroprevalence and risk factors associated with HBV and HCV infection among Kuje prison inmates, Nigeria. Methods & Materials: A cross-sectional study was conducted in 2016. Inmates who consented were randomly selected and stratified into convicts and awaiting trial stratum. Interviewer administered Questionnaires were used to obtain information on participants socio-demographic characteristics, HBV risk factors, previous HBV test and vaccination history. Blood samples were collected from all participants and analysed for HCV, HBsAg, HBsAb, HBcAb, HBeAg and HBeAb markers using rapid lateral chromatographic immunoassay kit. HBsAg positive samples were confirmed using ELISA. Epi-info version 7.2.0 was used for univariate, bivariate, and multivariate analysis. Results: 271 inmates (63 convicts and 208 awaiting trial inmates) were recruited for the study. The mean age of the participants was 32.7 SD ± 9 years. Of the 116(42.8%) who had ever heard of HBV infection, 114 (98%) had poor knowledge of the disease. HCV sero-prevalence was found to be 5.9%, (95% CI; 3.4-9.6) and HBV 13.7%, (95% CI; 9.8-18.3). 55.4% (95% CI; 49.2-61.4) of inmates were susceptible to HBV infection, 20.7% (95% CI; 16.0-26.0) had past or resolved HBV infection while 10.3% (95% CI; 7.0-14.6) had acquired natural or artificial HBV Immunity. Factors found to be associated with HBV infection include age group ≤25 (aOR 8.0; 95% CI = 2.9-22.3), ever married (aOR = 4.2, 95% CI = 1.7-10.4) and history of alcohol consumption (aOR = 3.4, 95% CI = 1.3-8.4). Conclusion: There is poor knowledge and high sero-prevalence of HBV and HCV infection among Kuje inmates. This study demonstrates the need for prison focused health intervention initiatives in Nigeria. We advocated HBV vaccination for all susceptible inmates and treatment for HBV positive inmates to reduce the transmission of HBV infection among inmates.

Rapid detection of β-conglutin with a novel lateral flow aptasensor assisted by immunomagnetic enrichment and enzyme signal amplification

A simple, rapid and economic lateral flow immunochromatographic assay (LFICA) was designed for ultrasensitive detection of β-conglutin. Instead of antibodies and gold nanoparticles (AuNPs) used in conventional LFICA, a cognate aptamer duo, binding to β-conglutin and Fe3O4@Au core-shell nanoparticles, was applied in this study. An enzyme signal amplification strategy was used to enhance sensitivity. In addition, a new magnetic enrichment strategy was employed to further enhance sensitivity of the assay, slowing down movement of the capture probe (i.e., Fe3O4@Au nanostructures) using an external magnetic field. The novel LFICA assay can be completed within 20 min and achieved a detection limit of 8 fM, a thousand-times lower than similar assays without magnetic focusing. Overall, our results demonstrated the potential for the proposed LFICA sensor in rapid detection of β-conglutin without any special analytical expertise or instrumentations.

Immunochromatographic test for rapid serological diagnosis of human angiostrongyliasis

ObjectivesThe serological diagnosis of human infection with Angiostrongylus cantonensis remains problematic because there are no commercially available validated tests. Most laboratories use domestically prepared tests such as the enzyme-linked immunosorbent assay (ELISA) or immunoblotting. Since laboratory facilities are not always available in endemic areas, we developed and assessed a rapid lateral flow immunochromatographic assay (AcQuickDx Test) to detect anti-A. cantonensis antibodies in human serum. MethodsThe test device was assembled with purified 31-kDa glycoprotein as diagnostic antigen and with gold-labelled anti-human immunoglublin-G as the detector reagent. A total of 97 serum samples were tested – 19 samples from clinically diagnosed patients with detectable A. cantonensis-specific antibody in immunoblotting; 43 samples from patients with other parasitic diseases, i.e. gnathostomiasis (n=13), toxocariasis (n=2), trichinellosis (n=2), hookworm infection (n=4), filariasis (n=5), cysticercosis (n=9), paragonimiasis (n=2), opisthorchiasis (n=3), and malaria (n=3); and 35 samples from normal healthy subjects. ResultsThe sensitivity, specificity, positive predictive value and negative predictive value of AcQuickDx Test to detect anti-A. cantonensis specific antibodies in serologically confirmed angiostrongyliasis cases, were 100%, 98.72%, 95% and 100%, respectively. Positive AcQuickDx was observed in 1 of 4 cases with hookworm infections. No positive AcQuickDx was observed in cases with other parasitic diseases, and the individual healthy subjects. ConclusionsAcQuickDx Test is rapid, highly sensitive and specific, and easy to perform without additional equipment or ancillary supplies. It yields results that are interpreted visually, and possesses a long shelf-life at room temperature. Thus, it can be applied as an additional test for clinical diagnostic support of angiostrongyliasis either in conventional laboratories or for remote areas where laboratory infrastructure is not available.

Development of Colloidal Gold-Based Immunochromatographic Assay for Rapid Detection of Goose Parvovirus.

Goose parvovirus (GPV) remains as a worldwide problem in goose industry. For this reason, it is necessary to develop a new diagnostic approach that is easier and faster than conventional tests. A rapid immunochromatographic assay based on antibody colloidal gold nanoparticles specific to GPV was developed for the detection of GPV in goose allantoic fluid and supernatant of tissue homogenate. The monoclonal antibodies (Mab) was produced by immunizing the BALB/c mice with purified GPV suspension, and the polyclonal antibody (pAb) was produced by immunizing the rabbits with recombinant VP3 protein. The colloidal gold was prepared by the reduction of gold salt with sodium citrate coupled with Mab against GPV. The optimal concentrations of the coating antibody and capture antibody were determined to be 1.6 mg/ml and 9 μg/ml. With visual observation, the lower limit was found to be around 1.2 μg/ml. Common diseases of goose were tested to evaluate the specificity of the immune colloidal gold (ICG) strip, and no cross-reaction was observed. The clinical detection was examined by carrying out the ICG strip test with 92 samples and comparing the results of these tests with those obtained via agar diffusion test and polymerase chain reaction (PCR) test. Therefore, the ICG strip test was a sufficiently sensitive and accurate detection method for a rapid screening of GPV.