Reactivity of serum samples from patients with a flavivirus infection measured by immunofluorescence assay and ELISA

Abstract Purpose Vitamin D (VitD) is a pleiotropic hormone with effects on a multitude of systems and metabolic pathways. Consequently, the relevance of a sufficiently high VitD serum level becomes self-evident. Methods A rapid immunofluorescence assay designed for the point-of-care measurement of serum VitD3 solely was tested. Inter- and intra-assay validation, double testing and result comparison with a standardized laboratory method were performed. Results An overall linear correlation of r = 0.89 (Pearson, 95% CI 0.88–0.92, p < 0.01) between the point of care and the conventional reference assay was registered. Accuracy and precision were of special interest at cut-points (10 ng/ml [mean deviation 1.7 ng/ml, SD 1.98 ng/ml, SE 0.16 ng/ml], 12 ng/ml [MD 0.41, SD 1.89, SE 0.19] and 30 ng/ml [MD − 1.11, SD 3.89, SE 0.35]). Only a slight deviation was detected between the two assays when using fresh (r = 0.91, 95% CI 0.86–0.94, p < 0.01) and frozen serum samples (r = 0.86, 0.82–0.89, p < 0.01). Results remained steady when samples were frozen several times. Inter- and intra-assay validation according to the CLSI protocol as well as multiuser testing showed stable results. Conclusion This novel, innovative, and controlled study indicates that the evaluated rapid point of care VitD assay is reliable, accurate, and suited for clinical practice.

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A case of human monocytic ehrlichiosis in Serbia

Srpski arhiv za celokupno lekarstvo ◽

10.2298/sarh1402079a ◽

2014 ◽

Vol 142 (1-2) ◽

pp. 79-82 ◽

Cited By ~ 3

Author(s):

Bogdan Arsic ◽

Ana Gligic ◽

Elizabeta Ristanovic ◽

Branislav Lako ◽

Aleksandar Potkonjak ◽

...

Keyword(s):

Indirect Immunofluorescence ◽

Clinical Picture ◽

Peripheral Blood ◽

Immunofluorescence Assay ◽

High Fever ◽

Tick Bite ◽

Indirect Immunofluorescence Assay ◽

Ehrlichia Chaffeensis ◽

Serum Samples ◽

History Of

Introduction. Ehrlichiosis is a bacterial zoonosis transmitted by hematophagous arthropods - ticks. In humans, it occurs as monocytic, granulocytic, and ewingii ehrlichiosis. Pathological process is based on parasitic presence of Ehrlichia organisms within peripheral blood cells - monocytes and granulocytes. Case Outline. Fifty-two year old patient was admitted to hospital due to high fever of over 40?C that lasted two days, accompanied with chills, muscle aches, malaise, loss of appetite, headache, confusion, breathing difficulties, and mild dry cough. The history suggested tick bite that occurred seven days before the onset of disease. Doxycycline was introduced and administered for 14 days, causing the disease to subside. Indirect immunofluorescence assay was used to analyze three serum samples obtained from this patient for Ehrlichia chaffeensis antibodies, and peripheral blood smear was evaluated for the presence of Ehrlichia and Ehrlichia aggregation into morulae. Conclusion. Ehrlichiosis should be considered in each case where there is a history of tick bite together with the clinical picture (high fever, chills, muscle aches, headache, generalized weakness and malaise, and possible maculopapular rash). The presence of Ehrlichia chaffeensis antibodies was confirmed in a patient with the history of tick bite, appropriate clinical picture and indirect immunofluorescence assay. This confirmed the presence of human monocytotropic ehrlichiosis, a disease that is uncommonly identified in our country.

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Immunofluorescence Assay for Detection of Human Metapneumovirus-Specific Antibodies by Use of Baculovirus-Expressed Fusion Protein

Clinical and Diagnostic Laboratory Immunology ◽

10.1128/cdli.12.1.202-205.2005 ◽

2005 ◽

Vol 12 (1) ◽

pp. 202-205 ◽

Cited By ~ 16

Author(s):

Nobuhisa Ishiguro ◽

Takashi Ebihara ◽

Rika Endo ◽

Xiaoming Ma ◽

Ryo Shirotsuki ◽

...

Keyword(s):

Trichoplusia Ni ◽

Respiratory Infections ◽

Recombinant Baculovirus ◽

Immunofluorescence Assay ◽

Human Metapneumovirus ◽

Specific Method ◽

Serum Samples ◽

F Protein ◽

Hmpv Infection ◽

Well Correlation

ABSTRACT Human metapneumovirus (hMPV) has recently been identified as an etiological agent of acute respiratory infections. The hMPV fusion (F) protein has been indicated to be a major antigenic determinant that mediates effective neutralization and protection against hMPV infection. We developed a new immunofluorescence assay (IFA) using Trichoplusia ni (Tn5) insect cells infected with a recombinant baculovirus-expressing hMPV F protein (Bac-F IFA). A total of 200 serum samples from Japanese people 1 month to 41 years old were tested for immunoglobulin G antibodies to hMPV F protein by Bac-F IFA. The results were compared with those of the conventional IFA based on hMPV-infected LLC-MK2 cells (hMPV IFA). The titers obtained by the two IFAs correlated well (correlation coefficient of 0.88), and the concordance of seroreactivities between the two IFAs was 91% (κ = 0.76). For 192 of the 200 serum samples, the titers obtained by the Bac-F IFA were equal to or higher than those obtained by the hMPV IFA. These results indicated that the Bac-F IFA was more sensitive than the hMPV IFA and that the majority of the antibodies detected by the hMPV IFA reacted with the hMPV F protein. The Bac-F IFA is a more reliable, sensitive, and specific method for the detection of hMPV antibodies than is the hMPV IFA.

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Variables associated with the prevalence of anti-Leishmania spp. antibodies in dogs on the tri-border of Foz do Iguaçu, Paraná, Brazil

Revista Brasileira de Parasitologia Veterinária ◽

10.1590/s1984-296120180055 ◽

2018 ◽

Author(s):

Renata Cristina Ferreira Dias ◽

Vanete Thomaz-Soccol ◽

Aline Kuhn Sbruzzi Pasquali ◽

Silvana Maria Alban ◽

Ricardo Cancio Fendrich ◽

...

Keyword(s):

Rapid Test ◽

Immunofluorescence Assay ◽

Confirmatory Test ◽

Serum Samples ◽

Leishmania Spp ◽

Confirmatory Analysis ◽

The City ◽

Public Collection ◽

Geographical Characteristics ◽

Immunoenzymatic Assay

Abstract The aim of this study was to investigate the occurrence of anti-Leishmania spp. antibodies in dogs from localities in the city of Foz do Iguaçu, Paraná state, Brazil, on the border with Argentina and Paraguay. Blood samples dogs were collected to perform the following serologic tests: immunochromatographic DPP® rapid test, indirect immunoenzymatic assay (ELISA) and indirect immunofluorescence assay (IFA). In 2012, 285 dogs were analyzed on Argentina border, and in 2013, serum samples from 396 dogs on the border of Paraguay were collected. Using ELISA for screening and IFA for the confirmatory test, the results showed that the antibody prevalence was 1.8% (5/285) on the border of Argentina and 3.0% (12/396) on Paraguay border. When using the DPP® for screening and ELISA as a confirmatory analysis, we observed a seroreagent prevalence in dogs of 2.5% (7/285) on Argentina border and 5.1% (20/396) on Paraguay border. The non-public collection of domestic waste (p= 0.0004) was shown to be associated with leishmaniasis. This study shows the presence of leishmaniasis and suggest the emergence of canine visceral leishmaniasis in state of Paraná due to the confirmed occurrence of seroreactive dogs on Argentina and Paraguay border, which has environmental and geographical characteristics that favor the spread of the parasite.

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Occurrence of Ehrlichia canis and Hepatozoon canis and probable exposure to Rickettsia amblyommatis in dogs and cats in Natal, RN

Revista Brasileira de Parasitologia Veterinária ◽

10.1590/s1984-296120180065 ◽

2019 ◽

Vol 28 (1) ◽

pp. 151-156 ◽

Cited By ~ 1

Author(s):

Marcos Gomes Lopes ◽

Felipe da Silva Krawczak ◽

Julia Teresa Ribeiro de Lima ◽

Gislene Fatima da Silva Rocha Fournier ◽

Igor da Cunha Lima Acosta ◽

...

Keyword(s):

Spotted Fever ◽

Immunofluorescence Assay ◽

Ehrlichia Canis ◽

Hepatozoon Canis ◽

Spotted Fever Group ◽

Accession Number ◽

Serum Samples ◽

Control Center ◽

Related Genotype ◽

Babesia Spp

Abstract Occurrence of infection or exposure to Ehrlichia canis, Hepatozoon canis and Rickettsia spp. was detected in feral cats living in two fragments from Atlantic rainforest, in Natal, RN, Brazil, and in dogs living around the parks. While serum samples were collected from 155 animals (53 cats living in the parks; 29 dogs living in human homes around the parks; and 73 dogs living at an animal control center - ACC), spleen samples were collected from 20 dogs that were euthanized at ACC. Serum samples were analyzed to Rickettsia spp. and E. canis antibodies using the indirect immunofluorescence assay. Seventeen of the 102 dogs (17%) had E. canis antibodies and 13% (20/155) of all dogs and cats (i.e. 3% (3/102) of the dogs and 32% (17/53) of the cats) were seropositive for Rickettsia spp. antigens. The animals were therefore been exposed to R. amblyommatis or by a very closely related genotype. Among the 20 dog spleen samples analyzed, eight were PCR positive for E. canis and two for H. canis (GenBank accession number MG772657 and MG772658, respectively). In none of the spleen samples were obtained amplicons for Babesia spp. through PCR. This study provided the first evidence that Rickettsia of the spotted fever group is circulating among dogs and cats in Natal.

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Seroprevalence of Antitransglutaminase and Antiendomysium Antibodies in Adult Colombian Blood Bank Donors

Canadian Journal of Gastroenterology and Hepatology ◽

10.1155/2020/7541941 ◽

2020 ◽

Vol 2020 ◽

pp. 1-6

Author(s):

Sara Paredes-Echeverri ◽

Ayda N. Rodríguez ◽

Wilmer A. Cárdenas ◽

Belén Mendoza de Molano ◽

John M. González

Keyword(s):

Native American ◽

Cross Sectional Study ◽

Immunofluorescence Assay ◽

High Reactivity ◽

Blood Bank ◽

Enzyme Linked Immunosorbent Assay ◽

Serum Samples ◽

Cross Sectional ◽

Prevalence Studies ◽

Hla Dq2

Celiac disease (CD) is an autoimmune enteropathy induced by the ingestion of gluten from wheat, barley, and rye in genetically susceptible individuals. The global prevalence of CD is 1.4%. However, most of the prevalence studies have been conducted in Caucasian populations; few studies have been performed in Latin America. The aim of this study is to determine the seroprevalence of auto-antibodies used as markers for CD in a Colombian cohort. In this cross-sectional study, the serum samples from Colombian donors of the National Red Cross Blood Bank were collected between June and September 2017 in Bogotá, Colombia. All sera were tested for IgA antitissue transglutaminase (TTG) by enzyme-linked immunosorbent assay. Seropositive sera were tested for IgA antiendomysium (EMA) using indirect immunofluorescence assay. The ancestral genetic composition was determined in donor samples with antibody assay reactivity. Those with two seroreactive assays were typed for HLA class II DQ2 and DQ8. In total, 228 blood donors participated in the study. Among them, 113 were females (49.56%) with an average age of 31.63 years (SD ± 12.99); males had an average of 34.71 years (SD ± 13.01). Only 3 (1.31%) donors reported chronic diarrhea and nonintentional weight loss; 11 (4.82%) had a family history of CD. For the serological assays, 11 donors (4.82%) were seroreactive to IgA anti-TTG: 3 had high reactivity and 8 had low reactivity. Of those seroreactive to IgA anti-TTG, 3 (1.32%) were also seroreactive to anti-EMA, and they were typed as HLA-DQ8 or HLA-DQ2. The baseline ancestral percentage of the seroreactive donors was higher for European and Native American than for African genes. The seroprevalence for anti-TTG and anti-EMA with the presence of HLA-DQ8 and HLA-DQ2 was 1.32%. Additionally, 4.82% donor participants were reactive only for anti-TTG. Compared with other studies, our findings suggest that Colombia has a high prevalence of CD markers.

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Frequency of antibodies and risk factors associated with Toxoplasma gondii infection in backyard pig production in the city of Mossoró, state of Rio Grande do Norte, Brazil

Revista Brasileira de Parasitologia Veterinária ◽

10.1590/s1984-29612019036 ◽

2019 ◽

Vol 28 (3) ◽

pp. 508-513 ◽

Cited By ~ 2

Author(s):

Isabela Maria Campanelli dos Santos ◽

Alexandro Iris Leite ◽

Maria Eduarda Chiaradia Furquim ◽

Diego Carlos de Souza Zanatto ◽

Simone de Jesus Fernandes ◽

...

Keyword(s):

Risk Factors ◽

Rio Grande ◽

Female Gender ◽

Immunofluorescence Assay ◽

P Value ◽

Serum Samples ◽

Igg Antibody ◽

Source Of Infection ◽

Antibody Titers ◽

Toxoplasma Gondii Infection

Abstract Toxoplasmosis is an important zoonosis for pregnant women and immunosuppressed people. The pig population also becomes infected by this pathogen, and undercooked or raw meat is an important source of infection for humans. The aims of the present study were to evaluate the rate of exposure of pigs to T. gondii in the municipality of Mossoró, Rio Grande do Norte and seek to identify associations with possible risk factors. Blood samples were collected from 412 pigs and were analyzed using the immunofluorescence assay. Among these 412 serum samples, 40.7% were seropositive for T. gondii. The IgG antibody titers were 64 (56 specimens), 128 (32), 256 (37), 512 (23), 1024 (14), 2048 (5) and 4046 (1). Seropositivity for T. gondii was found to be related (p-value < 0.05) to the following factors: female gender, semi-confined rearing system, use of well water, dewormed animals, presence of cats, goats, sheep, mice and vultures on the farm and carcasses left on the ground. In contrast, seropositivity was not related (p-value < 0.05) to the age of the pigs, type of facility or feeding with human food remains. Preventive measures need to be adopted on the farms studied here, with the aim of decreasing the animals’ intake of sporulated oocysts.

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Epidemiological Study of Thogoto and Dhori Virus Infection in People Bitten by Ticks, and in Sheep, in an Area of Northern Spain

International Journal of Environmental Research and Public Health ◽

10.3390/ijerph17072254 ◽

2020 ◽

Vol 17 (7) ◽

pp. 2254

Author(s):

Lourdes Lledó ◽

Consuelo Giménez-Pardo ◽

María Isabel Gegúndez

Keyword(s):

Virus Infection ◽

Epidemiological Study ◽

Human Subjects ◽

Acute Infection ◽

Immunofluorescence Assay ◽

Northern Spain ◽

Serum Samples ◽

Igm Antibodies

There is little information on Thogoto virus (THOV) and Dhori virus (DHOV)infection in Spain. A total of 283 serum samples from 150 human subjects (78 males, 72 females) bitten by ticks, as well as samples from 120 sheep (one per animal), were studied by immunofluorescence assay. All human and animal subjects were from the province of Palencia in northern Spain. Eight human subjects had antibodies against THOV (seroprevalence: 5.3%) and six had antibodies against DHOV (seroprevalence: 4%); titers ranged between 1/32–1/256 and 1/32–1/128, respectively. No significant differences were seen in seroprevalence in terms of gender or age, although people with antibodies were significantly more likely to have had contact with livestock for professional reasons. One subject with an acute infection had IgM antibodies to both viruses and seroconverted to IgG. For the sheep, 24 serum samples were positive for antibodies to THOV (seroprevalence: 20%) and 32 for antibodies to DHOV (seroprevalence: 26.8%); titers ranged between 1/16 and 1/128. The seroprevalence of both viruses was significantly higher in animals < 4 years of age. Together, these results reveal the circulation of DHOV and THOV in humans and sheep in the province of Palencia. Sheep might be used as indicators of the presence of these organisms.

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Cat-Scratch disease in Crete: an update

Infectious Disease Reports ◽

10.4081/idr.2011.3210 ◽

2011 ◽

Vol 3 (2) ◽

pp. 15 ◽

Cited By ~ 2

Author(s):

Georgios Minadakis ◽

Emmanouil Angelakis ◽

Dimosthenis Chochlakis ◽

Yannis Tselentis ◽

Anna Psaroulaki

Keyword(s):

Bartonella Henselae ◽

Immunofluorescence Assay ◽

Positive Lymph Node ◽

Cat Scratch Disease ◽

Outdoor Activity ◽

Pcr Assay ◽

Serum Samples ◽

Molecular Assays ◽

Number Of Patients ◽

Whole Blood Sample

There are few epidemiological and clinical studies about the presence of cat scratch disease (CSD) on the island of Crete. The objective of this study was to analyze a large number of patients with suspected CSD to define the frequency of Bartonella infections in Crete. From January 2005 to October 2008, we studied patients with suspected CSD from hospitals in Crete. Sera of the referred patients were tested by immunofluorescence assay (IFA). For some patients, we also received lymph nodes and blood samples that we tested for the presence of Bartonella henselae by molecular assays. Overall, we tested 507 serum samples and we found 56 (11%) cases of CSD. PCR assay was positive for 2 patients; one had a B. henselae positive lymph node and the other a positive whole blood sample. Significantly more CSD cases (62.5%, 35 of 56) were reported in children than in infants and adults (P<0.05). Moreover, we identified that most cases of CSD occurred between May and September (P=0.002) and December and January. CSD is prevalent in Crete and is mostly associated with an increase in outdoor activity.

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Novel Immunofluorescence Assay Using Recombinant Nucleocapsid-Spike Fusion Protein as Antigen To Detect Antibodies against Severe Acute Respiratory Syndrome Coronavirus

Clinical and Diagnostic Laboratory Immunology ◽

10.1128/cdli.12.2.321-328.2005 ◽

2005 ◽

Vol 12 (2) ◽

pp. 321-328 ◽

Cited By ~ 8

Author(s):

Qigai He ◽

Ivanus Manopo ◽

Liqun Lu ◽

Bernard P. Leung ◽

Hiok Hee Chng ◽

...

Keyword(s):

Severe Acute Respiratory Syndrome ◽

Fusion Protein ◽

Autoimmune Diseases ◽

Recombinant Baculovirus ◽

Immunofluorescence Assay ◽

Attractive Alternative ◽

Sf9 Cells ◽

Serum Samples ◽

Detection Rates ◽

Singapore General Hospital

ABSTRACT Severe acute respiratory syndrome (SARS) is caused by a novel and highly infectious virus named SARS coronavirus (SARS-CoV). Among the serological tests currently available for the detection of SARS-CoV, a whole-virus-based immunofluorescence assay (IFA) was considered one of the most sensitive assays and served as a “gold standard” during the SARS epidemic in Singapore in 2003. However, the need to manipulate live SARS-CoV in the traditional IFA limits its wide application due to the requirement for a biosafety level 3 laboratory and the risk of laboratory infection. Previously, we have identified two immunodominant epitopes, named N195 and Sc, in the two major structural proteins, the N and S proteins, of SARS-CoV (Q. He, K. H. Chong, H. H. Chng, B. Leung, A. E. Ling, T. Wei, S. W. Chan, E. E. Ooi, and J. Kwang, Clin. Diagn. Lab. Immunol., 11:417-422, 2004; L. Lu, I. Manopo, B. P. Leung, H. H. Chng, A. E. Ling, L. L. Chee, E. E. Ooi, S. W. Chan, and J. Kwang, J. Clin. Microbiol. 42:1570-1576, 2004). In the present study, the N195-Sc fusion protein was highly expressed in insect (Sf9) cells infected with a recombinant baculovirus bearing the hybrid gene under the control of a polyhedrin promoter. An IFA based on Sf9 cells producing the fusion protein was standardized with 23 serum samples from patients with SARS, 20 serum samples from patients with autoimmune diseases, and 43 serum samples from healthy blood donors. The detection rates were comparable to those obtained with a commercial SARS-CoV IFA kit (EUROIMMUN, Gross Groenau, Germany) and a conventional IFA performed at the Singapore General Hospital. Our data showed that the newly developed IFA could detect SARS-CoV in 22 of the 23 SARS-CoV-positive serum samples and gave no false-positive results when the sera from patients with autoimmune diseases and healthy individuals were tested. The detection rate was identical to those of the two whole-virus-based IFAs. Thus, the novel N-S fusion antigen-based IFA could be an attractive alternative to present whole-virus-based IFAs for the diagnosis of SARS-CoV infection.

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