scholarly journals Chikungunya Fever in Southern Thailand, 2018

2021 ◽  
Author(s):  
Natthaphon Nanakorn ◽  
Theerakamol Pengsakul ◽  
Kannika Bunrod ◽  
Suwich Thammapalo ◽  
Pathomporn Prikchoo ◽  
...  
Keyword(s):  
South African ◽  
Rapid Test ◽  
Febrile Illness ◽  
Positive Sequence ◽  
Rt Pcr ◽  
Serum Samples ◽  
Serological Tests ◽  
Recent Infection ◽  
Southern Thailand ◽  
The Indian Ocean

Infection by the mosquito-borne chikungunya virus (CHIKV) causes acute febrile illness and debilitating arthralgia. Outbreaks are sometimes not recognized because of its clinical resemblance to the more common dengue fever ubiquitous in tropical countries. An upsurge of dengue-like illness was reported in Satun province located in southern Thailand during the rainy season in 2018. We investigated probable outbreak of CHIKV disease. We collected serum samples from 127 patients and tested for CHIKV infection based on nucleic acid and serological tests. CHIKV RNA amplified by real-time reverse-transcription polymerase chain reaction (RT-PCR) and IgM antibody against CHIKV were determined by immunochromatographic rapid test. Mosquitoes in the community were also trapped and tested for CHIKV. Conventional RT-PCR on initially positive samples was performed to obtain nucleotide sequences for subsequent phylogenetic analysis. In all, 39% (50/127) of the samples tested positive for CHIKV RNA, IgM, or both. Of these, CHIKV RNA was identified in 17% (21/127) of the samples. Fourteen percent (18/127) of the samples were simultaneously positive for both IgM and IgG, which suggest recent infection. One sample tested positive for both CHIKV IgM and RNA. Several samples from Aedes aegypti and Aedes albopictus mosquitoes were also CHIKV RNA-positive. Sequence analysis revealed that the Satun CHIKV belonged to the Indian Ocean lineage within the East/Central/South African (ECSA) clade with residues K211E and A226 in the E1 gene, and G205S and V264A in the E2 gene. The ECSA strain of CHIKV continues to evolve and possesses virulent potential despite causing prior outbreaks in the region.

scholarly journals Utility of rapid diagnostic kit tests for diagnosis of suspected dengue fever

2019 ◽  
Vol 7 (5) ◽  
pp. 1670
Author(s):  
Sarita Otta ◽  
Bichitrananda Swain
Keyword(s):  
Platelet Count ◽  
Dengue Fever ◽  
Rapid Test ◽  
Febrile Illness ◽  
Serum Samples ◽  
Serological Tests ◽  
Ns1 Antigen ◽  
Elisa Technique ◽  
Low Platelet Count ◽  
Sensitivity Specificity

Background: Dengue fever often presents as an undifferentiated febrile illness requiring a laboratory test for identification. Serological tests particularly on rapid kits for the detection of NS1Antigen, IgG and IgM antibodies are the most commonly performed test across the country.Methods: The serum samples of suspected dengue cases were tested by Rapid test kits for assessing all the three parameters as well as by ELISA for NS1 antigen test. The platelet count of the patients was obtained from automated coulter counter. The results thus obtained were analyzed in Excel format.Results: The serum samples from 304 suspected Dengue fever cases were received in the lab, of which 190 samples were positive either by rapid or ELISA and 176 when rapid card test was considered alone Highest seropositivity of dengue cases were observed in the age group of ≥60 years (79.2%) followed by 45-59 years (70.7%). On rapid test, 78 cases were NS1 antigen positive of which 60 cases were positive only for NS1 antigen. When NS1 rapid and ELISA tests when compared, 16 kit negative tests were positive on ELISA while 34 kit positive tests were ELISA negative.  Sensitivity, specificity, PPV and NPV when only NS1 was considered on rapid test kits when compared with ELISA were 78.9%, 87.8%, 63.8% and 93.8%. 33.5% of serologically positive cases of Dengue had low platelet count on admission while only among negative cases 17.2% had a low platelet.Conclusions: Rapid kits often show variable results thus needing a validation of them from end user. As a positive dengue test result is an essential prerequisite for diagnosis thus it is essential that for serological tests ELISA technique should be used for reporting. Thus, it also mandates more efforts at decentralization of NVBDCP to include both government and non government institutions.

scholarly journals DENGUE OUTBREAK IN MATO GROSSO STATE, MIDWESTERN BRAZIL

2015 ◽  
Vol 57 (6) ◽  
pp. 489-496 ◽  
Author(s):  
Letícia Borges da Silva HEINEN ◽  
Nayara ZUCHI ◽  
Belgath Fernandes CARDOSO ◽  
Marcelo Adriano Mendes dos SANTOS ◽  
Mauricio Lacerda NOGUEIRA ◽  
...  
Keyword(s):  
Asian American ◽  
Yellow Fever Virus ◽  
Febrile Illness ◽  
Rt Pcr ◽  
Serum Samples ◽  
Mato Grosso ◽  
Denv Serotypes ◽  
Genotype Iii ◽  
Large Outbreak ◽  
Southeast Asian American

Dengue virus (DENV) is the most frequent arbovirus worldwide. In this study, we report a large outbreak in Mato Grosso State (MT). Serum samples from 604 patients with acute febrile illness for less than five days were inoculated in C6/36 cells, then infected cells were subjected to an indirect immunofluorescence test for DENV serotypes and yellow fever virus. Serum samples were submitted to a multiplex-semi-nested-RT-PCR for 11 flaviviruses. DENV-4 was isolated in 150/604 (24.8%) and DENV-1 in 19/604 (3.1%) specimens. By RT-PCR, 331 (54.8%) samples tested positive for DENV; 321 had single infections (DENV-4 n = 305; DENV-1 n = 15; DENV-3 n = 1), nine had co-infections of DENV-1/DENV-4, and one of DENV-2/DENV-4. DENV-4 was detected in 315/331 (95.2%) positive patients from 17 municipalities, and DENV-1 in 24/331 (7.2%) patients from five cities in north-central MT and the city of Cuiaba. The incidence of infection was higher in patients aged 20-39 (142/331; 42.9%). The NS5 partial nucleotide sequence of DENV-1 was most similar to that of genotype V, DENV-2 to Southeast Asian/American, DENV-3 to genotype III, and DENV-4 to genotype II strains, considered the most frequent strains in Brazil. This outbreak coincided with the introduction of DENV-4 in the state. Cuiaba was hyperendemic for the four DENV serotypes, highlighting the necessity for arbovirus surveillance in MT.

Maiden outbreaks of dengue virus 1 genotype III in rural central India

2014 ◽  
Vol 143 (2) ◽  
pp. 412-418 ◽  
Author(s):  
P. V. BARDE ◽  
B. K. KORI ◽  
M. K. SHUKLA ◽  
P. K. BHARTI ◽  
G. CHAND ◽  
...  
Keyword(s):  
Dengue Virus ◽  
Phylogenetic Analyses ◽  
Dengue Infection ◽  
Central India ◽  
Febrile Illness ◽  
Control Measures ◽  
Serum Samples ◽  
Serological Tests ◽  
Genotype Iii ◽  
Virus Serotype

SUMMARYDengue is regarded as the most important arboviral disease. Although sporadic cases have been reported, serotypes responsible for outbreaks have not been identified from central India over the last 20 years. We investigated two outbreaks of febrile illness, in August and November 2012, from Korea district (Chhattisgarh) and Narsinghpur district (Madhya Pradesh), respectively. Fever and entomological surveys were conducted in the affected regions. Molecular and serological tests were conducted on collected serum samples. Dengue-specific amplicons were sequenced and phylogenetic analyses were performed. In Korea and Narsinghpur districts 37·3% and 59% of cases were positive, respectively, for dengue infection, with adults being the worst affected. RT–PCR confirmed dengue virus serotype 1 genotype III as the aetiology. Ninety-six percent of infections were primary. This is the first time that dengue virus 1 outbreaks have been documented from central India. Introduction of the virus into the population and a conducive mosquitogenic environment favouring increased vector density caused the outbreak. Timely diagnosis and strengthening vector control measures are essential to avoid future outbreaks.

scholarly journals Diagnostic Properties of Three SARS-CoV-2 Antibody Tests

Diagnostics ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1441
Author(s):  
Suelen Basgalupp ◽  
Giovana dos Santos ◽  
Marina Bessel ◽  
Lara Garcia ◽  
Ana Carolina de Moura ◽  
...  
Keyword(s):  
Rapid Test ◽  
Epidemiological Studies ◽  
Antibody Detection ◽  
Sample Collection ◽  
Rt Pcr ◽  
Igg Antibody ◽  
Serological Tests ◽  
High Agreement ◽  
High Level ◽  
Antibody Tests

Serological assays emerged as complementary tools to RT-PCR in the diagnosis of SARS-CoV-2 as well as being needed for epidemiological studies. This study aimed to assess the performance of a rapid test (RT) compared to that of serological tests using finger prick blood samples. A total of 183 samples were evaluated, 88 of which were collected from individuals with negative RT-PCR and 95 from positive RT-PCR individuals. The diagnostic performance of RT (WONDFO®) and LUMIT (PROMEGA®) were compared to that of ELISA (EUROIMMUN®) for detecting antibodies against SARS-CoV-2 according to time from symptoms onset. The IgG antibody tests were detected in 77.4% (LUMIT), 77.9% (RT), and 80.0% (ELISA) of individuals. The detection of antibodies against SARS-CoV-2 increases in accordance with increasing time from symptoms onset. Considering only time from symptoms onset >21 days, the positivity rate ranged from 81.8 to 97.0% between the three tests. The RT and LUMIT showed high agreement with ELISA (agreement = 91.5%, k = 0.83, and agreement = 96.3%, k = 0.9, respectively) in individuals who had symptoms 15 to 21 days before sample collection. Compared to that of the ELISA assay, our results show sensitivity ranged from 95% to 100% for IgG antibody detection in individuals with symptoms onset between 15 and 21 days before sample collection. The specificity was 100% in individuals with symptoms onset >15 days before serological tests. This study shows good performance and high level of agreement of three immunoassays for the detection of SARS-CoV-2 antibodies.

scholarly journals Evaluation of the performance of three serological tests for diagnosis of Leishmania infantum infection in dogs using latent class analysis

2020 ◽  
Vol 29 (4) ◽  
Author(s):  
Asier Basurco ◽  
Alda Natale ◽  
Katia Capello ◽  
Antonio Fernández ◽  
María Teresa Verde ◽  
...  
Keyword(s):  
Sensitivity And Specificity ◽  
Leishmania Infantum ◽  
Latent Class ◽  
Rapid Test ◽  
Antibody Test ◽  
Latent Class Models ◽  
Canine Leishmaniasis ◽  
Enzyme Linked Immunosorbent Assay ◽  
Serum Samples ◽  
Serological Tests

Abstract Canine leishmaniasis (CanL) is a disease caused by Leishmania infantum. Serological methods are the most common diagnostic techniques used for the diagnosis of the CanL. The objective of our study was to estimate the sensitivity and specificity of one in-house ELISA kit (ELISA UNIZAR) and three commercially available serological tests (MEGACOR Diagnostik GmbH) including an immunochromatographic rapid test (FASTest LEISH®), an immunofluorescent antibody test (MegaFLUO LEISH®) and an enzyme-linked immunosorbent assay (MegaELISA LEISH®), using latent class models in a Bayesian analysis. Two hundred fifteen serum samples were included. The highest sensitivity was achieved for FASTest LEISH® (99.38%), ELISA UNIZAR (99.37%), MegaFLUO LEISH® (99.36%) followed by MegaELISA LEISH® (98.49%). The best specificity was obtained by FASTest LEISH® (98.43%), followed by ELISA UNIZAR (97.50%), whilst MegaFLUO LEISH® and MegaELISA LEISH® obtained the lower specificity (91.94% and 91.93%, respectively). The results of present study indicate that the immunochromatographic rapid test evaluated FASTest LEISH® show similar levels of sensitivity and specificity to the quantitative commercial tests. Among quantitative serological tests, sensitivity and specificity were similar considering ELISA or IFAT techniques.

scholarly journals Evaluation of nine serological rapid tests for the detection of SARS-CoV-2

2020 ◽  
Vol 44 ◽  
pp. 1
Author(s):  
Marcela Mercado ◽  
Jeadran Malagón-Rojas ◽  
Gabriela Delgado ◽  
Vivian Vanesa Rubio ◽  
Lida Muñoz Galindo ◽  
...  
Keyword(s):  
Study Groups ◽  
Cross Sectional Study ◽  
Igg Antibodies ◽  
Sectional Study ◽  
Rt Pcr ◽  
Serum Samples ◽  
Serological Tests ◽  
Cross Sectional ◽  
Diagnostic Aid ◽  
Rapid Tests

Objective. To evaluate the operative capacity of nine serological rapid tests to detect the IgM/IgG antibodies response in serum from patients with SARS-CoV-2 in different clinical stages. Methods. A cross-sectional study of serological rapid tests was designed to compare the performance of the evaluated immunochromatographic tests for the diagnosis of SARS-CoV-2. A total of 293 samples was used, including negatives, asymptomatic, and symptomatic serum samples. Results. The sensitivity of the evaluated tests was low and moderate in the groups of asymptomatic serum samples and the group of serums coming from patients with less than 11 days since the onset of the symptoms. The specificity for the anti-SARS-CoV-2 antibodies tests ranged between 86.5%-99% for IgM and 86.5%-99.5% for IgG. The sensitivity and the likelihood ratio were different according to the study groups. The usefulness of these tests is restricted to symptomatic patients and their sensitivity is greater than 85% after 11 days from the appearance of symptoms. Conclusions. Serological tests are not an adequate strategy for the identification of asymptomatic and pre-symptomatic patients. Serological rapid tests for the detection of specific anti-SARS-CoV-2 antibodies can be used as a diagnostic aid, but diagnosis must be confirmed by RT-PCR. Rapid tests should be reserved for patients with symptoms lasting more than 11 days.

scholarly journals Sero-prevalence of anti-SARS-CoV-2 Antibodies in Addis Ababa, Ethiopia

2020 ◽  
Author(s):  
Berhanu Nega Alemu ◽  
Adamu Addissie ◽  
Gemechis Mamo ◽  
Negussie Deyessa ◽  
Tamrat Abebe ◽  
...  
Keyword(s):  
Serological Test ◽  
Addis Ababa ◽  
Rapid Test ◽  
Cross Sectional Study ◽  
Rt Pcr ◽  
Serological Tests ◽  
Cross Sectional ◽  
History Of ◽  
Community Transmission ◽  
Pcr Test

AbstractBackgroundAnti-SARS-CoV-2 antibody tests are being increasingly used for sero-epidemiological purposes to provide better understanding of the extent of the infection in the community, and monitoring the progression of the COVID-19 epidemic. We conducted sero-prevalence study to estimate prior infection with with SARS-CoV-2 in Addis Ababa.MethodsA cross-sectional study was done from April 23 to 28, 2020 among 301 randomly selected residents of Addis Ababa; with no known history of contact with confirmed COVID-19 person. Interviews on socio demographic and behavioural risk factor followed by serological tests were performed for SARS-CoV-2 IgM, and IgG antibodies, using COVID-19 IgG/IgM Rapid Test Cassette. The test has sensitivity of 87·9% and specificity of 100% for lgM; and a sensitivity of 97·2% and specificity of 100% for IgG. RT-PCR test was also done on combined nasopharyngeal and oropharengeal swabs as an important public health consideration.FindingsThe unadjusted antibody-based crude SARS-CoV-2 prevalence was 7·6% and the adjusted true SARS-CoV-2 prevalence was estimated at 8·8% (95% CI 5·5%-11·6%) for the study population. Higher sero-prevalence were observed for males (9.0%), age below 50 years (8.2%), students and unemployed (15.6%), those with primary education (12.1%), smokers (7.8%), alcohol consumers (8.6%), chatt-chewers (13.6%) and shish smokers (18.8%). Seroprevalence was not significantly associated neither with socio-demographic not behavioral characteristics. According to the findings, possibly more individuals had been infected in Addis Ababa than what was being detected and reported by RT-PCR test suggestive of community transmission. The use of serological test for epidemiological estimation of the extent of SARS-CoV-2 epidemic gives a more precise estimate of magnitude which would be used for further monitoring and surveillance of the magnitude of the SARS CoV-2 infection.

scholarly journals Rapid Serological Tests for SARS-COV-2: Diagnostic Performance of Four Commercial Assays

2020 ◽  
Author(s):  
Sérgio Monteiro de Almeida ◽  
Regiane Nogueira Spalanzani ◽  
Meri Bordignon Nogueira ◽  
Beatriz Sanada Spiri ◽  
Barbara Maria Cavalli ◽  
...  
Keyword(s):  
Diagnostic Performance ◽  
Rapid Test ◽  
Nucleic Acid Amplification ◽  
Control Group ◽  
Serum Samples ◽  
Serological Tests ◽  
Test Kit ◽  
Healthy Control ◽  
One Step ◽  
Substantial Heterogeneity

Abstract Background. This study aimed to assess the diagnostic performance of lateral flow immunochromatographic assays (LFA) of four different manufacturers to identify SARS-CoV-2 antibodies (IgM, IgG or total), comparing them with the nucleic acid amplification test (NAAT) or clinical defined (definite or probable SARS-CoV-2 infection respectively). Methods. 119 serum samples were randomly selected by convenience and distributed in the groups: (1) Group with SARS-CoV-2 infection [n=82; RT-qPCR positive (definite, n=70), and probable (n=12)]; (2) other diseases [n= 27; other viruses identified (n=8), SARS of other etiologies (n=19)]; (3) healthy control group (n=10). LFA essays of four manufacturers were compared: MedTest Coronavírus (COVID-19) IgG/IgM (MedLevensohn, Brazil); COVID-19 IgG/IgM ECO Test (Ecodiagnóstica, Brazil); Camtech COVID-19 IgM/IgG Rapid Test Kit (Camtech Diagnostics Pte Ltd, Singapore); and one Step COVID-19 Test for total antibodies (Guangzhou Wondfo Biotech Co, China).Results. The four tests studied showed high diagnostic performance characteristics for the diagnoses of definite or probable SARS-CoV-2 infection. The best measures were for the Wondfo test: sensitivity (86.59%; 95%CI, 77.26-93.11%); specificity (100%; 90.51-100%); DOR (257; 60-1008); LR+ (33.43; 4.82-231.85); LR− (0.13; 0.08 - 0.23); accuracy (90.76%; 84.06- 95.29%); Matthews Correlation coefficient (MCC) 0.82. Although considering only the probable SARS-CoV-2 infection (PCR-) cases, all the kits studied showed limited values.Conclusion. Our data demonstrate the excellent performance of LFA for the diagnoses of definite or probable SARS-CoV-2 infection. There was substantial heterogeneity in sensitivities of IgM and IgG antibodies among the manufacturers. LFA tests cannot replace molecular diagnostics, but should be used as additional screening tool.

scholarly journals Rapid Serological Tests for SARS-COV-2: Diagnostic Performance of Four Commercial Assays

2020 ◽  
Author(s):  
Sérgio Monteiro de Almeida ◽  
Regiane Nogueira Spalanzani ◽  
Meri Bordignon Nogueira ◽  
Beatriz Sanada Spiri ◽  
Barbara Maria Cavalli ◽  
...  
Keyword(s):  
Diagnostic Performance ◽  
Rapid Test ◽  
Nucleic Acid Amplification ◽  
Control Group ◽  
Serum Samples ◽  
Serological Tests ◽  
Test Kit ◽  
Healthy Control ◽  
One Step ◽  
Substantial Heterogeneity

Abstract Background. This study aimed to assess the diagnostic performance of lateral flow immunochromatographic assays (LFA) of four different manufacturers to identify SARS-CoV-2 antibodies (IgM, IgG or total), comparing them with the nucleic acid amplification test (NAAT) or clinical defined (definite or probable SARS-CoV-2 infection respectively). Methods. 119 serum samples were randomly selected by convenience and distributed in the groups: (1) Group with SARS-CoV-2 infection [n=82; RT-qPCR positive (definite, n=70), and probable (n=12)]; (2) other diseases [n= 27; other viruses identified (n=8), SARS of other etiologies (n=19)]; (3) healthy control group (n=10). LFA essays of four manufacturers were compared: MedTest Coronavírus (COVID-19) IgG/IgM (MedLevensohn, Brazil); COVID-19 IgG/IgM ECO Test (Ecodiagnóstica, Brazil); Camtech COVID-19 IgM/IgG Rapid Test Kit (Camtech Diagnostics Pte Ltd, Singapore); and one Step COVID-19 Test for total antibodies (Guangzhou Wondfo Biotech Co, China).Results. The four tests studied showed high diagnostic performance characteristics for the diagnoses of definite or probable SARS-CoV-2 infection. The best measures were for the Wondfo test: sensitivity (86.59%; 95%CI, 77.26-93.11%); specificity (100%; 90.51-100%); DOR (257; 60-1008); LR+ (33.43; 4.82-231.85); LR− (0.13; 0.08 - 0.23); accuracy (90.76%; 84.06- 95.29%); Matthews Correlation coefficient (MCC) 0.82. Although considering only the probable SARS-CoV-2 infection (PCR-) cases, all the kits studied showed limited values.Conclusion. Our data demonstrate the excellent performance of LFA for the diagnoses of definite or probable SARS-CoV-2 infection. There was substantial heterogeneity in sensitivities of IgM and IgG antibodies among the manufacturers. LFA tests cannot replace molecular diagnostics, but should be used as additional screening tool.

A filtration-based rapid test using a partially purified third-stage larval antigen to detect specific antibodies for the diagnosis of gnathostomiasis

2017 ◽  
Vol 93 (1) ◽  
pp. 26-32 ◽  
Author(s):  
A. Ma ◽  
Y. Wang ◽  
X.L. Liu ◽  
H.M. Zhang ◽  
P. Eamsobhana ◽  
...  
Keyword(s):  
Rapid Test ◽  
Cross Reactivity ◽  
Serum Samples ◽  
Serological Tests ◽  
Promising Tool ◽  
Diagnostic Potential ◽  
Food Borne ◽  
Third Stage ◽  
Diagnostic Sensitivity And Specificity ◽  
Purified Antigen

AbstractHuman gnathostomiasis is an emerging food-borne parasitic disease caused by nematodes of the genusGnathostoma. Currently, serological tests are commonly applied to support clinical diagnosis. In the present study, a simple and rapid filtration-based test, dot immune–gold filtration assay (DIGFA) was developed using a partially purified antigen ofGnathostomathird-stage larvae (L3). A total of 180 serum samples were tested to evaluate the diagnostic potential of DIGFA for gnathostomiasis. The diagnostic sensitivity and specificity were 96.7% (29/30) and 100% (25/25), respectively. The cross-reactivity with sera from other helminthiasis patients ranged from 0 to 4%, with an average of 1.6% (2/125). DIGFA using a partially purified L3 antigen was not only simple and rapid, but also more accurate than standard assays for the diagnosis of human gnathostomiasis. DIGFA may represent a promising tool for application in laboratories or in the field, without requiring any instrumentation.

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