Conventional Serological Tests Research Articles

HIV self-testing knowledge, attitudes, and practices among Asian-born gay, bisexual, and other men who have sex with men in Australia: a qualitative study

BackgroundAchieving virtual elimination of HIV transmission in Australia requires a combination of high treatment rates and high testing coverage among individuals at risk of acquiring HIV. HIV self-testing (HIVST) is an additional testing approach for key populations.ObjectiveWe aimed to examine the knowledge, attitudes, and practices of HIVST among Asian-born gay, bisexual and other men who have sex with men (GBMSM).MethodsThis qualitative study used semi-structured interviews of overseas-born GBMSM of Asian background in Australia. Participants were recruited from personal networks, social media platforms, snowballing, and the Melbourne Sexual Health Centre. Twenty-five participants were purposively sampled with a range of ages and previous levels of experience with HIVST. Interview transcripts were imported into Nvivo 12 for data management.ResultsThe age of the participants ranged from 19 to 44 years, with a median of 30 years. Most were unaware of HIVST before the interview, and only a few had ever used one. All had limited sexual health knowledge (i.e., HIV testing, PrEP) before they arrived in Australia. Upon learning about HIVST during the interview, many expressed willingness to use HIVST, but in limited circumstances, such as traveling overseas, interim testing while taking on-demand PrEP, and point-of-sex testing. Almost all were open to distributing HIVST to their casual partners or friends, especially those they knew who engaged in high-risk sexual practice (i.e., condomless anal sex) and were not engaged in sexual healthcare. About half still preferred conventional serology testing because of regular HIV testing as part of PrEP prescription and the need for testing for other sexually transmitted infections.ConclusionHIVST may be an acceptable additional testing approach for HIV testing among Asian-born GBMSM. Peer education and secondary distribution may help raise HIVST awareness and use.

Correlation of HBV Core-Related Antigen with Conventional Serologic Indicators of Hepatitis B and Disease Stage.

Hepatitis B caused by hepatitis B virus (HBV) infection is a serious global public health issue. Currently, serological indicators serve as important markers for the diagnosis of hepatitis B. It has been found that HBV core-related antigen (HBcrAg) correlates well with intrahepatic cccDNA, intrahepatic HBV DNA, serum HBV DNA, and hepatitis B e antigen (HBeAg). To provide a more reliable basis for the diagnosis and treatment of hepatitis B, we explored the correlation between HBcrAg and conventional serologic testing indicators and disease staging. Five hundred forty-two patient serum samples were collected at the First Affiliated Hospital of Soochow University from November 2021 to March 2022. The serum HBcrAg was measured by the magnetic particle chemiluminescence method in addition with other serum indicators. HBcrAg statistically correlated with HBV DNA level (r = 0.655, p < 0.001) and HBeAg level (r = 0.945, p < 0.001. The mean HBcrAg levels in the immune-tolerant and immune-clearance phases were significantly higher than those in the immunologic-control phase and the reactivation phase. This study demonstrated that serum HBcrAg positively correlated with serum HBV DNA and HBeAg. Even in cases where HBV DNA and HBeAg are negative, there is still a higher positivity rate of HBcrAg in hepatitis B patients. HBcrAg is a reliable serum marker to avoid underdiagnosis of occult HBV infection.

Post-therapeutic cure criterion in chronic Chagas disease using Trypanosoma cruzi chimeric proteins.

Chagas disease (CD) is a neglected disease caused by Trypanosoma cruzi Chagas, 1909. Causative treatment can be achieved with two drugs: benznidazole or Nifurtimox. There are some gaps that hinder progress in eradicating the disease. There is no test that can efficiently assess cure control after treatment. Currently, the decline in anti-T. cruzi antibody titres is assessed with conventional serological tests, which can take years. However, the search for new markers of cure must continue to fill this gap. The present study aimed to evaluate the decline in serological titres using chimeric proteins after treatment with benznidazole in chronic patients diagnosed with CD. It was a prospective cross-sectional cohort study between 2000 and 2004 of T. cruzi-positive participants from the Añatuya region (Argentina) treated with benznidazole. Serum samples from ten patients were collected before treatment (day zero) and after the end of treatment (2, 3, 6, 12, 24 and 36 months). For the detection of anti-T. cruzi antibodies, an indirect ELISA was performed using two chimeric recombinant proteins (IBMP-8.1 and IBMP-8.4) as antigens. The changes in reactivity index within the groups before and after treatment were evaluated using the Friedman test. All participants experienced a decrease in serological titres after treatment with benznidazole, especially IBMP-8.1. However, due to the small number of samples and the short follow-up period, it is premature to conclude that this molecule serves as a criterion for sustained cure. Further studies are needed to validate tests based on these or other biomarkers to demonstrate parasitological cure.

Comparative Study of a Novel Lateral Flow Rapid Test with Conventional Serological Test Systems for the Diagnosis of Canine Leishmaniosis in Croatia and Brazil.

Control of canine infections with Leishmania infantum (L. infantum), a major zoonotic disease in Brazil and southern Europe, is becoming increasingly important due to its close proximity to humans, the increasing import of dogs from endemic regions and the impact of climate change on vector spreading. Simple, rapid and reliable diagnostic tests are therefore needed to detect infected dogs. Here, we re-evaluated different serological methods for the diagnosis of canine leishmaniosis (CanL) in Croatia and Brazil. The diagnostic performance of the indirect fluorescent antibody test (IFAT) and the VetLine® Leishmania ELISA (GSD Frankfurt, Germany) was compared with three rKLi8.3-based diagnostic test systems, the rKLi8.3 ELISA (GSD Frankfurt, Germany), the INgezim® Leishma CROM (GSD Madrid, Spain) lateral flow test (LFT) and the VetBlot®Leishmania LineBlot (GSD Frankfurt, Germany). CanL symptomatic dogs were efficiently diagnosed by all tests, except the VetLine® Leishmania ELISA, which is based on whole Leishmania antigens. The advantage of rKLi8.3 was also observed in oligo- and asymptomatic dogs from Brazil and Croatia, although with reduced diagnostic efficiency compared to symptomatic dogs. Similar to IFAT and rKLi8.3 ELISA, the LFT did not cross-react with other common canine pathogens; it showed very high specificity for healthy dogs from endemic regions in both countries and did not react with healthy, vaccinated dogs in Brazil. In conclusion, serodiagnostic tests based on the rKLi8.3 antigens are superior to whole parasite antigens, and the LFT has the advantage of providing a laboratory-independent, rapid and specific diagnosis of CanL.

An α-Gal antigenic surrogate as a biomarker of treatment evaluation in Trypanosoma cruzi-infected children. A retrospective cohort study.

Proper evaluation of therapeutic responses in Chagas disease is hampered by the prolonged persistence of antibodies to Trypanosoma cruzi measured by conventional serological tests and by the lack of sensitivity of parasitological tests. Previous studies indicated that tGPI-mucins, an α-Gal (α-d-Galp(1→3)-β-d-Galp(1→4)-d-GlcNAc)-rich fraction obtained from T. cruzi trypomastigotes surface coat, elicit a strong and protective antibody response in infected individuals, which disappears soon after successful treatment. The cost and technical difficulties associated with tGPI-mucins preparation, however, preclude its routine implementation in clinical settings. We herein developed a neoglycoprotein consisting of a BSA scaffold decorated with several units of a synthetic α-Gal antigenic surrogate (α-d-Galp(1→3)-β-d-Galp(1→4)-β-d-Glcp). Serological responses to this reagent, termed NGP-Tri, were monitored by means of an in-house enzyme-linked immunosorbent assay (α-Gal-ELISA) in a cohort of 82 T. cruzi-infected and Benznidazole- or Nifurtimox-treated children (3 days to 16 years-old). This cohort was split into 3 groups based on the age of patients at the time of treatment initiation: Group 1 comprised 24 babies (3 days to 5 months-old; median = 26 days-old), Group 2 comprised 31 children (7 months to 3 years-old; median = 1.0-year-old) and Group 3 comprised 26 patients (3 to 16 years-old; median = 8.4 years-old). A second, control cohort (Group 4) included 39 non-infected infants (3 days to 5 months-old; median = 31 days-old) born to T. cruzi-infected mothers. Despite its suboptimal seroprevalence (58.4%), α-Gal-ELISA yielded shorter median time values of negativization (23 months [IC 95% 7 to 36 months] vs 60 months [IC 95% 15 to 83 months]; p = 0.0016) and higher rate of patient negative seroconversion (89.2% vs 43.2%, p < 0.005) as compared to conventional serological methods. The same effect was verified for every Group, when analyzed separately. Most remarkably, 14 out of 24 (58.3%) patients from Group 3 achieved negative seroconversion for α-Gal-ELISA while none of them were able to negativize for conventional serology. Detailed analysis of patients showing unconventional serological responses suggested that, in addition to providing a novel tool to shorten follow-up periods after chemotherapy, the α-Gal-ELISA may assist in other diagnostic needs in pediatric Chagas disease. The tools evaluated here provide the cornerstone for the development of an efficacious, reliable, and straightforward post-therapeutic marker for pediatric Chagas disease.

Chagas disease treatment efficacy markers: experiences from a Phase III study with nifurtimox in children

Determining the success of antitrypanosomal therapy for Chagas disease is challenging, particularly in the chronic phase of the disease, because seropositivity persists for a long time after successful antitrypanosomal treatment and is known to be related to the duration of Trypanosoma cruzi infection. Seroconversion to negative by two or more conventional serologic tests is the currently accepted measure of efficacy, and studies suggest no significant change in seropositivity if left untreated. However, there is no guidance for industry on how to establish the effectiveness of drugs intended for the treatment of Chagas disease. Due to the lack of validated sensitive, specific, easy-to-use markers that allow early monitoring of the efficacy of antitrypanosomal treatment in an efficient manner, we used seroreduction measured by two conventional enzyme-linked immunosorbent assays in addition to the currently accepted criterion for what constitutes a cure, seroconversion to negative, as a surrogate parameter for efficacy in a Phase III pediatric trial with nifurtimox. The measures for confirmation of the antitrypanosomal efficacy of nifurtimox were discussed with US FDA. In this perspective article, we present our experiences obtained from a pediatric study on Chagas disease with an established drug using a surrogate efficacy parameter in addition to the established criterion for a cure.

ELISA F29 -A therapeutic efficacy biomarker in Chagas disease: Evaluation in pediatric patients treated with nifurtimox and followed for 4 years post-treatment.

Measurement of the success of antitrypanosomal treatment for Chagas disease is difficult, particularly in the chronic phase of the disease, because anti-Trypanosoma cruzi antibodies persist in serum for prolonged periods. We studied the effects of nifurtimox administered by two different treatment regimens on the T. cruzi calcium-binding flagellar protein F29 in children diagnosed with Chagas disease measured using an enzyme-linked immunosorbent assay (ELISA) technique (ELISA F29). In a phase 3, randomized, double-blind, parallel-group, historically controlled study (ClinicalTrials.gov NCT02625974), blood samples obtained from children diagnosed with Chagas disease and treated with nifurtimox for either 60 days or 30 days were analyzed using an ELISA with an F29 recombinant protein as the antigen, as well as conventional serological tests (recombinant ELISA and indirect hemagglutination assay). In an exploratory approach, serological response to nifurtimox treatment was evaluated for 4 years post-treatment. In both treatment groups, the number of patients with negative ELISA F29 values increased over the period of observation. The incidence rate of negative seroconversion using ELISA F29 was 22.94% (95% CI: 19.65%, 26.63%) in the 60-day treatment group and 21.64% (95% CI: 17.21%, 26.86%) in the 30-day treatment group. In the subpopulation of patients who tested seropositive for F29 before nifurtimox treatment, 88 patients (67.7%) in the 60-day regimen and 39 patients (59.1%) in the 30-day regimen were F29 seronegative at 4 years post-treatment. All patients who had a positive ELISA F29 test at baseline and seroconverted to negative measured by conventional serology reached seronegativity in ELISA F29 earlier than in conventional serology. The results demonstrate a serological response to treatment with nifurtimox measured by the ELISA F29 test in children diagnosed with Chagas disease. The F29-based ELISA can be considered a potential early marker of response to antitrypanosomal therapy for Chagas disease. ClinicalTrials.gov NCT02625974.

Population pharmacokinetics of benznidazole in neonates, infants and children using a new pediatric formulation.

There is a major need for information on pharmacokinetics (PK) of benznidazole (BNZ) in children with Chagas disease (CD). We conducted a multicentre population PK, safety and efficacy study in children, infants and neonates with CD treated with BNZ (formulated in 100 mg tablets or 12.5 mg dispersible tablets, developed by the pharmaceutical company LAFEPE, in a collaboration with DNDi). 81 children 0-12 years old were enrolled at 5 pediatric centers in Argentina. Diagnosis of T. cruzi infection was confirmed by direct microscopic examination, or at least two positive conventional serological tests. Subject enrolment was stratified by age: newborns to 2 years (minimum of 10 newborns) and >2-12 years. BNZ 7.5 mg/kg/d was administered in two daily doses for 60 days. Five blood samples per child were obtained at random times within pre-defined time windows at Day 0 at 2-5 h post-dose; during steady state, one sample at Day 7 and at Day 30; and two samples at 12-24 h after final BNZ dose at Day 60. The primary efficacy endpoint was parasitological clearance by qualitative PCR at the end of treatment. Forty-one (51%) patients were under 2 years of age (including 14 newborns <1 month of age). Median age at enrolment was 22 months (mean: 43.2; interquartile range (IQR) 7-72 months). The median measured BNZ Cmax was 8.32 mg/L (IQR 5.95-11.8; range 1.79-19.38). Median observed BNZ Cmin (trough) concentration was 2 mg/L (IQR 1.25-3.77; range 0.14-7.08). Overall median simulated Css was 6.3 mg/L (IQR 4.7-8.5 mg/L). CL/F increased quickly during the first month of postnatal life and reached adult levels after approximately 10 years of age. Negative qPCR was observed at the end of treatment in all 76 patients who completed the treatment. Five patients discontinued treatment (3 due to AEs and 2 due to lack of compliance). We observed lower BNZ plasma concentrations in infants and children than those previously reported in adults treated with comparable mg/kg doses. Despite these lower concentrations, pediatric treatment was well tolerated and universally effective, with a high response rate and infrequent, mild AEs. Registered in clinicaltrials.gov #NCT01549236.

Differentiation of Salmonella vaccinated and infected animals by serological detection of antibody to T3SS effector SsaK in an indirect ELISA

The differentiation of animals that are vaccinated and those that are naturally infected with Salmonella is difficult by conventional serological tests. We have shown here an indirect Enzyme-linked immunosorbent assay for detection of Salmonella infection based on the presence of a Type III secretory effector SsaK in the sera.

Immunogenicity Response of Mus musculus var. Balb/C after Immunization using Flagellin Salmonella typhi Serovar Semarang.

&lt;b&gt;Background and Objective:&lt;/b&gt; The flagellin of &lt;i&gt;Salmonella typhi&lt;/i&gt; is potentially developed as an identifying antigen in a rapid diagnostic test instrument that may be more accurate than conventional serological tests. Therefore, this study aims to analyze the immunogenicity of flagellin &lt;i&gt;S. typhi&lt;/i&gt; as the basis for developing a typhoid fever diagnostic. &lt;b&gt;Materials and Methods:&lt;/b&gt; Flagellin was isolated from the bacterial culture of &lt;i&gt;S. typhi&lt;/i&gt; serovar Semarang and used as the primary antigen for vaccine assembly. Native flagellin antigen was immunized in Balb/C mice with injection doses of 2, 3, 4, 5 and 6 g/100 L in each group (K0-K5), respectively, via intraperitoneal cavity. Blood serum was collected to ELISA based-measurement for IL-6 and TNF-a titers. Then, specific immunoglobulin (Ig) of anti-flagellin was detected using in-house ELISA and western blotting. &lt;b&gt;Results:&lt;/b&gt; The findings in this study showed that immunization at the dose of 4-5 g/100 L significantly decreased the IL-6 titer, i.e., 8.33±0.87 pg mL&lt;sup&gt;1&lt;/sup&gt;, compared to control. The antibody titer test analysis showed the highest Ig-G anti-flagellin was found in K4 mice after immunization using a dose of 5 g/100 L with an average absorbance of Ig-G reaching 1.19 ±0.32. &lt;b&gt;Conclusion:&lt;/b&gt; The results indicated that the flagellin protein of &lt;i&gt;S. typhi&lt;/i&gt; serovar Semarang induces adaptive immune responses and produces specific antibodies against flagellin. The immunogenic properties of the flagellin protein of &lt;i&gt;S. typhi&lt;/i&gt; serovar Semarang potentially developed as a specific diagnostic marker. Further research may also focus on a beneficial feature of flagellin as a vaccine candidate.

A rapid colorimetric lateral flow test strip for detection of live Salmonella Enteritidis using whole phage as a specific binder.

Specific antibodies are essential components of immunoassay, which can be applied for the detection of pathogens. However, producing an antibody specific to live bacterial pathogens by the classical method of immunizing animals with live pathogens can be impractical. Phage display technology is an effective alternative method to obtain antibodies with the desired specificity against selected antigenic molecules. In this study, we demonstrated the power of a microarray-based technique for obtaining specific phage-derived antibody fragments against Salmonella, an important foodborne pathogen. The selected phage-displayed antibody fragments were subsequently employed to develop a lateral flow test strip assay for the detection of live Salmonella. The test strips showed specificity to Salmonella Enteritidis without cross-reactivity to eight serovars of Salmonella or other bacteria strains. The test strip assay requires 15 min, whereas the conventional biochemical and serological confirmation test requires at least 24 h. The microarray screening technique for specific phage-based binders and the test strip method can be further applied to other foodborne pathogens.

A diagnostic classifier for gene expression-based identification of early Lyme disease

BackgroundLyme disease is a tick-borne illness that causes an estimated 476,000 infections annually in the United States. New diagnostic tests are urgently needed, as existing antibody-based assays lack sufficient sensitivity and specificity.MethodsHere we perform transcriptome profiling by RNA sequencing (RNA-Seq), targeted RNA-Seq, and/or machine learning-based classification of 263 peripheral blood mononuclear cell samples from 218 subjects, including 94 early Lyme disease patients, 48 uninfected control subjects, and 57 patients with other infections (influenza, bacteremia, or tuberculosis). Differentially expressed genes among the 25,278 in the reference database are selected based on ≥1.5-fold change, ≤0.05 p value, and ≤0.001 false-discovery rate cutoffs. After gene selection using a k-nearest neighbor algorithm, the comparative performance of ten different classifier models is evaluated using machine learning.ResultsWe identify a 31-gene Lyme disease classifier (LDC) panel that can discriminate between early Lyme patients and controls, with 23 genes (74.2%) that have previously been described in association with clinical investigations of Lyme disease patients or in vitro cell culture and rodent studies of Borrelia burgdorferi infection. Evaluation of the LDC using an independent test set of samples from 63 subjects yields an overall sensitivity of 90.0%, specificity of 100%, and accuracy of 95.2%. The LDC test is positive in 85.7% of seronegative patients and found to persist for ≥3 weeks in 9 of 12 (75%) patients.ConclusionsThese results highlight the potential clinical utility of a gene expression classifier for diagnosis of early Lyme disease, including in patients negative by conventional serologic testing.

Differentially methylation of IFI44L gene promoter in Iranian patients with systemic lupus erythematosus and rheumatoid arthritis.

Systemic lupus erythematosus(SLE) and rheumatoid arthritis(RA) are multisystemicautoimmune diseases with multifactorial nature. Considering the limitations of the current conventional serological tests for the diagnosis of these diseases, researchers strive to find more new valid biomarkers. Sixty-nine patients with SLE, 63 patients with RA, and 71 healthy controls were recruited to evaluate the methylation level of interferon-induced protein 44-like(IFI44L) promoter. Quantitative methylation of the promoter region of the IFI44L gene was measured in extracted DNA of peripheral blood mononuclear cells (PBMCs) with methylation-quantification endonuclease-resistant DNA (MethyQESD) method. Our findings unveiled a drastic hypomethylation of IFI44L promoter in SLE and RA patients compared with healthy volunteers (mean: 40.23% ± 64.54%, 35.19% ± 24.09%, and 71.98% ± 23.83%, respectively; P < 0.001 for both SLE and RA). In comparison between SLE and RA patients with the control group, IFI44L promoter methylation had a sensitivity of 81.15% and 84.12%, respectively, and specificity was 76.05%. The promoter methylation level was not meaningfully different between SLE and RA patients (P = 0.267). Moreover, our analysis revealed that the methylation level of the IFI44L promoter was not significantly different between SLE disease activity and renal involvements (P > 0.05). While RA patients with a higher concentration of CRP had a lower DNA methylation level (P = 0.023). The methylation level of IFI44L promoter was lower in PBMCs of Iranian patients with SLE and RA than that in the control group. Furthermore, DNA methylation level of the IFI44L promoter had a negative correlation with RA disease activity. However, there was not a significant association with the clinical characteristics of SLE.

Evaluating the Clinical Utility of Staged Bronchoalveolar Lavage (BAL) Fluid Analysis in Adolescent and Adult Acute Leukemia and Lymphoma Patients with Febrile Neutropenia and Lung Infiltrates

▪Introduction:Lung infiltrates(LI) are seen in 30-45% of the patients with Febrile neutropenia(FN) in haematological malignancies.In FN patients with LI, accurate/probable microbiological diagnosis is possible in only 30 % with conventional blood culture and serological tests. BAL increases the microbiological diagnostic yield. The battery of microbiological tests done in BAL fluid analysis is not uniform.We evaluated a staged approach while analysing the BAL fluid sample, in the first stage we performed the routine cultures and antigen-based tests and in patients with negative results, we performed Polymerase Chain Reaction(PCR) tests guided by the radiological findings.Methods:This was a prospective observational study initiated after Institutional ethics committee approval and conducted at Tata memorial centre,Mumbai between November 2018 and June 2020.BAL testing was done as per a standard protocol(Sampsonas et al.) in hemodynamically stable patients with Spo2 more than 90% and platelet count above 300x10 9/L.Samples were sent for gram stain & bacterial cultures, ziehl neelsen stain and cultures, fungal stain and cultures and Galactomannan (ELISA) and an extra sample was preserved in an EDTA vacutainer at 10-20 degree C. If none of the initial reports were positive, then stored BAL sample was sent for PCR testing guided by the radiology and clinical picture i.e., with nodular infiltrates(Bacteria,Nocardia,Aspergillus,Mucor,P.Jiroveci,Mycobacterium TB,Atypical Mycobacterium TB) and with diffuse micronodular infiltrates Viruses,Legionella,mycoplasma PCR tests were sent. The causal association of the isolated organism was defined as per AGIHO guidelines(G. Maschmeyer et al.)The Primary objective is proportion of patients with a confirmed microbiological diagnosis using staged BAL analysis. The Secondary Objectives are proportion of patients who had a change in antimicrobial therapy,Feasibility of doing a Bronchoscopy and Proportion of Patients who develop Major or Minor complications during procedure and the 4 and 12weeks Clinical and Radiological Outcomes.A sample size of 130 patients was required for incidence of 50%(40-60%) positivity with 10% variation at 95% confidence interval.Results:A total of 172 patients were eligible of which 50 patients are not enrolled due to physician discretion in 37 patients,9 lost for followup and 2 refused consent and one patient expired and one palliated and 122 patients are enrolled and of these BAL couldn't be done in 20 patients due to hypoxia,low platelets,poor GCS at the time of performing BAL and finally BAL is feasible in 83.6%(n=102/122) patients. Baseline characteristics of patients are mentioned in Table 1.Median age of the patients was 30 (15-65) years with 69.6% males (n=85/122). A confirmed microbiological diagnosis (G. Maschmeyer et al.) was established in 71.3%( 81 /122 ) of cases.Microbiological results are depicted in Table2.A change of antimicrobial based on BAL (addition and removal of antimicrobial) was done for 78 patients(63.8%) of which 42 had removal of antibacterial and 11 patients had removal of antifungals.Among 42 patients who had removal of antibiotics, by the end of 4weeks, 36(85.7%) had clinical response and 34 had radiological response,(4 died and 2 lost for followup).By the end of 12weeks, 31 patients had sustained clinical and radiological response (2 died, 2 lost to follow-up and 1 progressive disease).Among 11 patients with removal of antifungals 9 had clinical and radiological response by the end of 4weeks (1 died and 1 non responder) which was sustained at week 12.Complications of BALOne patient had a major complication (persistent hypoxia), while minor complications were recorded in 27/122 (22%) (Hypoxia-16, hypertension-8,tachycardia-3) during procedure and in 21/122 (17%) (Fever-8, bleeds-6, tachycardia-5,hypertension-2)upto 24 hours post procedure.Clinical and Radiological responses as per criteria( Figure 1)Conclusion:BAL fluid analysis improves the diagnostic yield in febrile neutropenia with lung infiltrates. This leads to a change in antimicrobials in a significant number of patients. It contributes to improved outcomes in this patient population. The test is feasible in a large majority, is safe and the staged approach helps in optimisation of resources. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Combined use of two rapid tests for the conclusive diagnosis of Chagas disease: a systematic scoping review

ObjectiveThe goal of this systematic scoping review is to collect and summarise scientific evidence regarding the validity of two simultaneous immunochromatographic tests for the conclusive diagnosis of Chagas disease. The...

Evaluation of chimeric proteins for serological diagnosis of brucellosis in cattle.

Background and Aim:An accurate diagnosis of Brucella-infected animals is one of the critical measures in eradication programs. Conventional serological tests based on whole-cell (WC) antigens and detecting antibodies against pathogen-associated lipopolysaccharide might give false-positive results due to the cross-reactivity with other closely related bacteria. This study evaluated the serological potential of Brucella spp. chimeric outer membrane proteins (Omps) as antigens in an indirect enzyme-linked immunosorbent assay (i-ELISA).Materials and Methods:The chimeric gene constructs of the most immunodominant regions of Brucella Omps 25+31, 25+19, and 19+31 were cloned into the pET28a expression vectors and transformed into Escherichia coli BL21 (DE3). The serological potential of chimeric proteins compared with single recombinant Omps (rOmps)19, 25, and/or 31 were studied on blood serum samples of (i) a rabbit immunized with killed Brucella abortus 19WC, (ii) mice immunized with single rOmps, (iii) cows seropositive for brucellosis by rose Bengal test, and (iv) cattle naturally and/or experimentally infected with brucellosis.Results:E. coli BL21 actively produced Brucella chimeric rOmps, the concentration of which reached a maximum level at 6 h after isopropyl-b-D-1-thiogalactopyranoside stimulation. Target proteins were antigenic and expressed in an active state, as recognized by rabbit anti-B. abortus antibodies in an i-ELISA and western blotting. Murine antibodies against the single rOmps reacted with chimeric antigens, and conversely, antichimeric antibodies found their epitopes in single proteins. Brucella chimeric rOmps showed higher antigenicity in blood sera of seropositive cattle kept in the hotbed of the infection and/or experimentally challenged with brucellosis than single proteins.Conclusion:Brucella chimeric recombinant outer membrane proteins could be a potential antigen candidate for developing an ELISA test for accurate diagnosis of bovine brucellosis.

Correlation between serology and nucleic acid amplification test in blood donors who are reactive for hepatitis B virus, hepatitis C and human immunodeficiency virus and evaluation of the epidemiological profile of infected people in blood centers in the State of Paraná

ObjectivesTo compare the results of conventional serological tests and molecular technology (NAT, Nucleic Acid Amplification Test), identify donors in the diagnostic window period, and determine the prevalence of hepatitis B virus (HBV), hepatitis C virus (HCV), and human immunodeficiency virus (HIV) among the samples of blood donors blocked by serological screening. MethodsA retrospective cross-sectional study was carried out by analyzing blood donor information contained in the database of 20 blood centers in Paraná, from January 2018 to December 2019. ResultsA total of 1,496 blood bags were reactive for HBV, HCV, or HIV in serological and/or NAT tests. The 20th Regional Health (RH) Unit had the greatest number of unfit individuals with altered screening for the three infections, with a prevalence of 0.70%. The lowest number of blocked blood donors occurred in the 15th RH, with a prevalence of 0.08%. The highest prevalence of HBV occurred in the 8th RH, with a reagent serology of 0.34% and a positive NAT of 0.17%. For HCV, the prevalence for reagent serology was 0.28%, while that for NAT was 0.02%, which occurred in the 20th RH. For HIV and for NAT, the prevalence of blood donors with positive serology occurred in the 20th RH, at 0.25% and 0.04%, retrospectively. The 13th RH had the highest prevalence of HIV in relation to NAT, that is, conventional serology in concomitance with NAT technology, at 0.07%. During the 2-year period, only 1 reactive donor in the 9th was found for NAT (HBV), in a diagnostic window. ConclusionIn Paraná’s blood centers, the inability to donate due to HBV, HCV, and HIV, occurred mainly in initial donors, men, those with >8 years of education, aged 16–45 years, married, and O positive. The most affected regions were located in the west and northwest of Paraná. Most of the results showed a discrepancy between the methodologies used.

Serological assays and host antibody detection in coronavirus-related disease diagnosis.

Coronaviruses (CoV) are a family of viral pathogens that infect both birds and mammals, including humans. Seven human coronaviruses (HCoV) have been recognized so far. HCoV-229E, -OC43, -NL63, and -HKU1 account for one-third of common colds with mild symptoms. The other three members are severe acute respiratory syndrome (SARS)-CoV, Middle East respiratory syndrome (MERS)-CoV, and SARS-CoV-2. These viruses are responsible for SARS, MERS, and CoV disease 2019 (COVID-19), respectively. A variety of diagnostic techniques, including chest X-rays, computer tomography (CT) scans, analysis of viral nucleic acids, proteins, or whole virions, and host antibody detection using serological assays have been developed for the detection of these viruses. In this review, we discuss conventional serological tests, such as enzyme-linked immunosorbent assay (ELISA), western blot (WB), immunofluorescence assay (IFA), lateral flow immunoassay (LFIA), and chemiluminescence immunoassay (CLIA), as well as biosensor-based assays that have been developed for diagnosing HCoV-associated diseases since 2003, with an in-depth focus on COVID-19.

A Review on: Lumpy Skin Disease: Enhance Awareness on the Epidemiological situation and Diagnosis; Prevention and Control Measures in Ethiopia

Lumpy skin disease (LSD) is an economically significant viral disease of cattle and caused by lumpy skin disease virus (LSDV). The virus is belonging to the genus Capri poxvirus (CaPV) of the family Poxviridae. Recently, the disease has been rapidly spreading to the Middle East, South east Europe and parts of Russian federation. The disease causes significant economic loss due to hide damage, loss of milk production, mastitis, infertility and death. Clinically, LSD is characterized by circumscribed skin nodules, fever, and abortions in females and sterility in males. LSD damages hides and causes death due to secondary bacterial infections. LSD is principally transmitted by blood-feeding arthropod vectors. However, transmission of the disease between animals is inefficient. Diagnosis is mainly based on observation of clinical signs and identification of the agent using conventional and real-time PCR methods, electron microscopy, and isolation of the virus in cell cultures, and using conventional serological tests. In endemic countries, vaccination is the only effective method to control the disease using live attenuated vaccines derived from Kenyan sheep and goat pox virus (KSGP) strains. However, there are reports of insufficient protection of the existing vaccines. Therefore; there is a need for more extensive data from the field and for larger-scale clinical trials to ensure the efficacy and safety of the current vaccines

How effective are rapid diagnostic tests for Chagas disease?

ABSTRACT Introduction: Diagnosis of chronic Chagas disease relies on the agreement of two conventional serological tests based on distinct antigens. These require cold to preserve reagents and samples, and equipment and trained personnel to run them. Moreover, results turnaround may be delayed for several weeks risking a loss to follow-up of infected subjects, summoning major disadvantages to access diagnosis (and treatment) in many highly endemic areas. Areas covered: Recent studies have shown the versatility of rapid diagnostic tests for the detection of chronic Trypanosoma cruzi infections in referral centers and in field campaigns, with a performance equivalent to that of conventional tools. Remarkably, RDTs do not require cold storage and provide results within an hour. Additionally, they are easy-to-use and can work with a tiny volume of finger-pricked whole blood. Altogether, major advantages toward generalizing their use as an alternative to conventional tests. Expert opinion: Already in 2021, only a small percentage of T. cruzi-infected people are diagnosed and treated. The unsuitability of currently used diagnostics, and of the recommended algorithm, to the conditions found in many regions do not help to fill this gap. RDTs stand as a promising solution, even though geographical validation should precede their implementation.