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Influenza and Other Respiratory Viruses Feb 2023The antigenicity of SARS-CoV-2 is a critical issue for the effectiveness of the vaccine, and thus, it should be phenotypically evaluated by serological assays as new...
BACKGROUND
The antigenicity of SARS-CoV-2 is a critical issue for the effectiveness of the vaccine, and thus, it should be phenotypically evaluated by serological assays as new field isolates emerge. The hemagglutination/hemagglutination inhibition (HA/HI) tests are well known as a representative method for antigenic analysis of influenza viruses, but SARS-CoV-2 does not agglutinate human or guinea pig red blood cells. Therefore, the antigenic analysis requires complicated cell-based assays using special equipment such as plate reader or ELISPOT analyzer.
METHODS
Based on the HA/HI tests for influenza viruses, we developed the particle agglutination/particle agglutination inhibition (PA/PAI) test to easily and rapidly quantify the virus and antibody using human angiotensin-converting enzyme 2 (hACE2)-bound latex beads. The virus titers were determined by mixing the beads and the virus from culture supernatant, settling it overnight, and then observing the sedimentation/agglutination pattern (PA test). The neutralization antibody titers were determined by mixing virus-infected hamster antisera in addition to the beads and virus (PAI test).
RESULTS
The PA titer was positively correlated with the plaque-forming units. The PAI titer using the hamster antisera clearly revealed the antigenic difference between the omicron and previous variants. The antigenic differences were supported by the results shown in other methods.
CONCLUSIONS
The PAI test is an easy and rapid method to analyze the antigenicity of SARS-CoV-2.
Topics: Animals; Humans; Guinea Pigs; SARS-CoV-2; COVID-19; Hemagglutination Inhibition Tests; Orthomyxoviridae; Agglutination; Immune Sera; Hemagglutinin Glycoproteins, Influenza Virus
PubMed: 36824396
DOI: 10.1111/irv.13093 -
Open Veterinary Journal Sep 2023Neurotropic viruses in the family Rhabdoviridae, genus , are what cause rabies, an acute, progressive, and highly lethal encephalomyelitis.
BACKGROUND
Neurotropic viruses in the family Rhabdoviridae, genus , are what cause rabies, an acute, progressive, and highly lethal encephalomyelitis.
AIM
Evaluation of the used diagnostic techniques to determine the most simple; rapid and accurate test for rabies virus (RABV) recognition in different specimens aiming to reach a rapid diagnosis as a step aid in the disease control and to prevent or even minimize the suspected hazard.
METHOD
The used techniques included an infection trial of Swiss mice with the mice-adapted challenge rabies virus followed by the detection of the virus in the infected mices' brains. Virus detection was carried out through the application BHK21 cell line infection; fluorescent antibody technique; latex agglutination test (LAT); direct enzyme-linked immunosorbent assay (ELISA); rabies antigen detection kit ELISA; conventional polymerase chain reaction (PCR).
RESULTS
It was found that virus inoculation in mice and BHK21 cell lines needs 5-7 days with positivity of 90% and 100%, respectively. Rapid antigen kit was able to detect rabies antigen in mice brains suspension and BHK21 infected fluid within 3-5 minutes with percentages of 60% and 55.5%, respectively. In 1-1.5 hours, the direct fluorescent antibody method (DFAT) detected 90% and 100% of the rabies antigen in BHK21 cell line infection and brain impressions, respectively. Latex agglutination showed clear results with 88.8% with BHK21 infected fluid within 3-5 minutes while it did not carry out on brain emulsions to prevent falsely positive results brought on by the presence of tissue fragments. Conventional one-step PCR revealed 100% positivity with either brain or cell culture preparations within 2 days. Direct ELISA showed 88.8% positivity with BHK21 infected fluid with 1 day of work.
CONCLUSION
Mice inoculation test, cell culture infection; DFAT and PCR are the most accurate techniques for the detection of RABV with a positivity of 90%-100% followed by LAT and ELISA with a positivity of 88.8%, and lastly, rabies antigen ELISA kit (RAK) with a positivity of 55.5%-60% taking in consideration the required time for each. In addition, the positivity % of the applied tests revealed their sensitivity and specificity.
Topics: Animals; Mice; Rabies virus; Rabies; Lyssavirus; Sensitivity and Specificity; Cell Culture Techniques
PubMed: 37842113
DOI: 10.5455/OVJ.2023.v13.i9.13 -
PLoS Neglected Tropical Diseases Aug 2023Lack of available sensitive point-of-care testing is one of the primary obstacles to the rapid diagnosis of leptospirosis. The purpose of this study was to test the...
BACKGROUND
Lack of available sensitive point-of-care testing is one of the primary obstacles to the rapid diagnosis of leptospirosis. The purpose of this study was to test the performance of two point-of-care tests, a clustered regularly interspaced short palindromic repeat (CRISPR)/CRISPR-associated protein 12a (CRISPR/Cas12a) fluorescence-based diagnostic assay (FBDA), a Leptospira immunoglobulin M (IgM) rapid diagnostic test (RDT), and the two tests combined.
METHODOLOGY/PRINCIPAL FINDINGS
For the diagnosis of 171 clinical samples, a recombinase polymerase amplification (RPA)-CRISPR/Cas12a FBDA for whole blood and Leptospira IgM RDT (Medical Science Public Health, Thailand) for serum were used. The confirmed cases were determined by using any positive qPCR, microscopic agglutination test (MAT), and culture results. Diagnostic accuracy was assessed on the first day of enrollment and stratified by the day after symptom onset. The overall sensitivity of the Leptospira IgM RDT and RPA-CRISPR/Cas12a FBDA was 55.66% and 60.38%, respectively. When the two tests were combined, the sensitivity rose to 84.91%. The specificity of each test was 63.08% and 100%, respectively, and 63.08% when combined. The sensitivity of the Leptospira IgM RDT rose on days 4-6 after the onset of fever, while the RPA-CRISPR/Cas12a FBDA continued to decrease. When the two tests were combined, the sensitivity was over 80% at different days post-onset of fever.
CONCLUSIONS/SIGNIFICANCE
The combination of Leptospira IgM RDT and RPA-CRISPR/Cas12 FBDA exhibited significant sensitivity for the detection of leptospires at various days after the onset of fever, thereby reducing the likelihood of misdiagnosis. The combination of these assays may be suitable for early leptospirosis screening in situations with limited resources.
Topics: Humans; Recombinases; Leptospira; CRISPR-Cas Systems; Leptospirosis; Antibodies, Bacterial; Fever; Immunoglobulin M
PubMed: 37624847
DOI: 10.1371/journal.pntd.0011596 -
Veterinary Clinical Pathology Oct 2019A definitive diagnosis of immune-mediated hemolytic anemia (IMHA) can be difficult to make. However, it is critical to differentiate IMHA from other causes of anemia due... (Review)
Review
BACKGROUND
A definitive diagnosis of immune-mediated hemolytic anemia (IMHA) can be difficult to make. However, it is critical to differentiate IMHA from other causes of anemia due to the impact on prognosis and outcome for IMHA patients. Recently published American College of Veterinary Internal Medicine recommendations for the diagnosis of IMHA should be followed to concurrently confirm ongoing anemia, verify in vivo hemolysis, and detect anti-erythrocyte antibodies. The reliability of immunologic IMHA tests varies depending on which test is used and how it is performed.
OBJECTIVES
Our aims were to determine which tests are currently used in veterinary medicine to diagnose IMHA and review the utility of assays that have historically been used to diagnose IMHA.
METHODS
A short survey was designed to see which diagnostic tests for IMHA were currently being used by veterinary practices. The survey was distributed via list-serves to veterinarians and veterinary technologists. A literature review was performed to report the utility of diagnostic tests for the diagnosis of IMHA.
RESULTS
Survey respondents indicated a variability in test protocols used to diagnose IMHA. Most respondents perform saline agglutination or Coombs' tests to detect anti-erythrocyte antibodies. Additional tests that can be used to support a diagnosis of IMHA are discussed in this review.
CONCLUSIONS
A standardized diagnostic approach should be followed to differentiate IMHA from other causes of anemia. Test methodology can vary from one laboratory to another, and clinicians should be familiar with the procedures used by their laboratory.
Topics: Anemia, Hemolytic, Autoimmune; Animals; Coombs Test; Diagnostic Tests, Routine; Dog Diseases; Dogs; Erythrocytes; Prognosis; Surveys and Questionnaires
PubMed: 31502273
DOI: 10.1111/vcp.12771 -
Journal de Mycologie Medicale Jun 2021This review sets out to highlighted knowledge gaps regarding the epidemiological, diagnostic (clinical and laboratory) and therapeutic aspects of otomycosis in Africa. A... (Review)
Review
This review sets out to highlighted knowledge gaps regarding the epidemiological, diagnostic (clinical and laboratory) and therapeutic aspects of otomycosis in Africa. A computerized literature search for otomycosis related articles were performed using MEDLINE. The search encompassed articles published in early January 1980 to May 2019 yielded 220 articles. Electronic search on PubMed was performed with the specific keywords. This review shows the higher prevalence rates of otomycosis in Africa. These prevalences varies from one country to the other and also from one population to another within the same country. The main symptoms are otalgia, otorrhea, hearing loss, aural fullness, pruritus, and tinnitus. Otomycosis is due to several predisposing factors, however, use of topical antibiotic/steroid eardrops, trauma to the external ear canal or instrumentation of the ear, being exposed to hot humid atmospheres, and close contact with water are the common risk factors. Aspergillus species are the most commonly identified organisms compared with Candida species. Worldwide, A. niger and C. albicans are the most commonly described agents of otomycosis in Africa. The Laboratory diagnosis of otomycosis is usually confirmed by mycologic tests relied on a set of evidences. Further conventional methods such as Chromagar Candida System, latex agglutination test, Biochemical tests (Api 20C AuxTM and auxanogram), phenotypical tests (Germ-tube and chlamydosporulation), and rRNA gene sequencing (PCR) are performed to improve diagnosis and the management of the disease. Adequate treatment of otomycosis includes microscopic suction clearance of fungal mass, discontinuation of topical antibiotics and treatment with antifungal eardrops for three weeks.
Topics: Africa; Antifungal Agents; Aspergillus; Candida; Fungi; Humans; Otomycosis; Prevalence
PubMed: 33516991
DOI: 10.1016/j.mycmed.2021.101115 -
Methods in Molecular Biology (Clifton,... 2021For assessing isolates of Listeria monocytogenes, serotype designation is the first subtyping method used. Methodologies used to assign serotype are currently evolving...
For assessing isolates of Listeria monocytogenes, serotype designation is the first subtyping method used. Methodologies used to assign serotype are currently evolving and will eventually be replaced with whole genome sequencing. Traditionally, serotyping has been done with agglutination reactions; however, alternative methods utilizing enzyme linked immunosorbent assay (ELISA) and polymerase chain reaction (PCR) are common. Described here are the three non-genomic methods and the advantages and disadvantages of each.
Topics: Agglutination Tests; Enzyme-Linked Immunosorbent Assay; Humans; Listeria monocytogenes; Listeriosis; Polymerase Chain Reaction; Serotyping
PubMed: 32975766
DOI: 10.1007/978-1-0716-0982-8_5 -
PloS One 2022Brucellosis is listed as one of six priority zoonoses in Tanzania's One Health strategic plan which highlights gaps in data needed for the surveillance and estimation of...
BACKGROUND
Brucellosis is listed as one of six priority zoonoses in Tanzania's One Health strategic plan which highlights gaps in data needed for the surveillance and estimation of human brucellosis burdens. This study collected data on current testing practices and test results for human brucellosis in Arusha region, northern Tanzania.
METHODS
Retrospective data were extracted from records at 24 health facilities in Arusha region for the period January 2012 to May 2018. Data were captured on: the test reagents used for brucellosis, procurement and testing protocols, the monthly number of patients tested for brucellosis and the monthly number testing positive. Generalised linear mixed models were used to evaluate relationships between health facility characteristics and the probability that brucellosis testing was conducted in a given month, and the proportion of individuals testing positive.
RESULTS
Four febrile Brucella agglutination tests were used widely. The probability of testing for brucellosis in a given month was significantly associated with an interaction between year of testing and facility ownership. Test probability increased over time with more pronounced increases in privately owned as compared to government facilities. The proportion of individuals testing positive for brucellosis was significantly associated with facility type and district, with individuals tested in hospitals in Meru, Monduli and Ngorongoro districts more likely to test positive.
CONCLUSIONS
Febrile Brucella agglutination tests, known for their poor performance, were the mainstay of brucellosis testing at health facilities in northern Tanzania. The study indicates that historical data on human brucellosis in Arusha and other regions are likely to provide an inaccurate measure of true disease burden due to poor performance of the tests used and variation in testing practices. Measures to address these identified shortcomings could greatly improve quality of testing and surveillance data on brucellosis and ultimately inform prevention and control of this priority disease.
Topics: Animals; Brucella; Brucellosis; Health Facilities; Humans; Retrospective Studies; Tanzania
PubMed: 35320293
DOI: 10.1371/journal.pone.0265612 -
Veterinary World 2023Brucellosis remains an endemic zoonotic disease in many developing countries, causing great harm to public health and devastating losses to livestock. One of the main... (Review)
Review
Brucellosis remains an endemic zoonotic disease in many developing countries, causing great harm to public health and devastating losses to livestock. One of the main reasons for the low effectiveness of anti-brucellosis measures is the lack of reliable methods for diagnosing infected animals throughout their lifespan. Classical serological tests, such as the tube agglutination test, rose Bengal plate test, and complement fixation test, as well as commercial enzyme-linked immunosorbent assay kits, are based on the detection of antibodies to the cell wall polysaccharide antigens of spp. smooth strains. As a result, they do not exclude cross-reactions with related bacteria and fail to differentiate between infected and vaccinated animals. Over the past decades, many attempts have been made to identify immunoreactive and pathogen-specific protein antigens. To date, several studies have investigated spp. recombinant proteins, including cell wall proteins, as the best antigens for diagnosing brucellosis in animals and humans. However, the available results on the specificity and sensitivity of serological tests based on cell wall proteins are ambiguous and sometimes contradictory. This review aims to provide an overview of the current state of knowledge of the diagnostic value of outer membrane and/or periplasmic proteins of spp. The goal is to identify future developments that may lead to reliable antigens for serological tests.
PubMed: 37621538
DOI: 10.14202/vetworld.2023.1390-1399 -
Scientific Reports Feb 2022Leptospirosis is a common global zoonotic disease of man and all farm animals. Although most leptospiral infections in sheep and goats are asymptomatic, they may play a...
Leptospirosis is a common global zoonotic disease of man and all farm animals. Although most leptospiral infections in sheep and goats are asymptomatic, they may play a role in the epidemiology of the disease by the spread of Leptospira through the urine. This study was carried out to evaluate the role of sheep and goats in the epidemiology of leptospirosis. Blood and urine samples were taken from 210 goats and 246 sheep. To detect antibodies, sera samples were tested with 8 live serovars of L. interrogans (Hardjo, Pomona, Grippotyphosa, Canicola, Ballum, Icterhemorrhagiae, Tarasovi, and Australis) by MAT. Then, urine samples were tested by Nested PCR targeting 16S rRNA gene for detection of pathogenic Leptospira. Results of MAT showed that 10.95% of goats and 8.53% of sheep had antibodies against at least one examined serovars. In both species, the highest reacting was L. i. Pomona with a rate of 68.18% and 56% in sheep and goats, respectively. Moreover, in PCR, 2 (0.95%) urine samples of goat and 12 (4.87%) urine samples of sheep were positive. All of the MAT positive studied animals were PCR negative and, statistical analysis showed that there was no relationship and agreement between the results of PCR and MAT in sheep (kappa = - 0.07, p > 0.05) and goats (kappa = - 0.02, p > 0.05). Finally, it is concluded that sheep and goats can excrete L. interrogans in the urine and thus transmit them to other animals and humans.
Topics: Agglutination Tests; Animals; Antibodies, Bacterial; Bacterial Zoonoses; Bacteriuria; Goat Diseases; Goats; Leptospira interrogans; Leptospirosis; Polymerase Chain Reaction; Seroepidemiologic Studies; Sheep; Sheep Diseases; Urine
PubMed: 35140240
DOI: 10.1038/s41598-022-05767-x -
Journal of Veterinary Research Mar 2022Trypanosomosis is an important disease of dromedary camels caused by the pathogenic protozoan . This study aimed to compare three different tests for its diagnosis in...
INTRODUCTION
Trypanosomosis is an important disease of dromedary camels caused by the pathogenic protozoan . This study aimed to compare three different tests for its diagnosis in this species: conventional microscopy, the card agglutination test for trypanosomosis/ (CATT/) and real-time PCR.
MATERIAL AND METHODS
Whole blood and serum samples collected from 77 dromedary camels of Abu Dhabi, United Arab Emirates, were analysed with the test methods stated. Statistical analysis was done using McNemar's chi-squared test, and Cohen's kappa index (κ) was calculated.
RESULTS
We obtained results with positivity of 18% (14/77) by microscopy, 22% by CATT (17/77) and 60% (46/77) by real-time PCR, with the chain reaction detecting at a respectively three- and two-fold greater rate than the other techniques. Analysis of the data revealed a relative sensitivity of 30.4% and 37.0% for microscopy and CATT, respectively, compared to real-time PCR. The difference between the real-time PCR's sensitivity and those of the other methods was statistically significant, with X values of 30.03 and 20.1, respectively (df = 1 and P = 0.05 in both cases). Agreement of microscopy results with those of with CATT was good (κ = 0.72; 95% CI = 0.62-0.82). Cohen's kappa index showed fair agreement of real-time PCR with microscopy (κ = 0.26; 95% CI = 0.16-0.36) whereas it was in poor agreement with CATT (κ = 0.09; 95% CI = 0.02-0.15).
CONCLUSION
Real-time PCR was found to be more sensitive than microscopy and CATT.
PubMed: 35582483
DOI: 10.2478/jvetres-2022-0002