scholarly journals Difference in SARS-CoV-2 attack rate between children and adults may reflect bias

2021 ◽  
Author(s):  
Zoë Hyde
Keyword(s):  
Polymerase Chain Reaction ◽  
Infectious Virus ◽  
Data Interpretation ◽  
Asymptomatic Infection ◽  
Household Contact ◽  
Serological Testing ◽  
Chain Reaction ◽  
Design Data ◽  
High Prevalence ◽  
Polymerase Chain

Abstract The epidemiology of coronavirus disease 2019 (COVID-19) in children has been challenging to establish, owing to the high prevalence of asymptomatic infection in this population. Lower secondary attack rates in children compared to adults have been observed in household contact studies, but there is evidence this may reflect lower testing in children and reduced exposure, rather than a genuine difference in biological susceptibility. Additionally, children may shed infectious virus for a shorter period than adults and their antibody response may be less broad, with implications for both polymerase chain reaction and serological testing. Improvements in study design, data collection, and data interpretation are required to better understand the epidemiology of COVID-19 in children.

scholarly journals EXPRESS: Clinical performance of the Elecsys® Anti-SARS-CoV-2 combined in an algorithm with two specific anti-IgG immunoassays for the evaluation of the serological response of patients with COVID-19 in a population with a high prevalence of infection

2021 ◽  
pp. 000456322110380
Author(s):  
Xavier Gabaldó-Barrios ◽  
Simona Iftimie ◽  
Anna Hernández-Aguilera ◽  
Isabel Pujol ◽  
Frederic Ballester ◽  
...  
Keyword(s):  
Immune Response ◽  
Polymerase Chain Reaction ◽  
Predictive Value ◽  
Clinical Performance ◽  
Polymerase Chain Reaction Test ◽  
Serological Response ◽  
Chain Reaction ◽  
Automated Assay ◽  
High Prevalence ◽  
Polymerase Chain

Background: Anti-SARS-CoV-2 antibodies have been used in the study of the immune response in infected patients. However, differences in sensitivity and specificity have been reported, depending on the method of analysis. The aim of the present study was to evaluate the diagnostic accuracy of an algorithm in which a high-throughput automated assay for total antibodies was used for screening and two semi-automated IgG-specific methods were used to confirm the results, and also to correlate the analytical results with the clinical data and the time elapsed since infection. Methods: We studied 306 patients, some hospitalized and some outpatients, belonging to a population with a high prevalence of COVID-19. One-hundred and ten patients were classified as SARS-CoV-2 negative and 196 as positive by polymerase chain reaction. Results: The algorithm and automated assay alone had a specificity and a positive predictive value of 100%, although the sensitivity and negative predictive value of the algorithm was higher. Both methods showed a good sensitivity from day 11 of the onset of symptoms in asymptomatic and symptomatic patients. The absorbance of the total antibodies was significantly higher in severely symptomatic than in asymptomatic or mildly symptomatic patients, which suggests the antibody level was higher. We found 15 patients that did not present seroconversion at 12 days from the onset of symptoms or the first polymerase chain reaction test. Conclusion: This study highlights the proper functioning of algorithms in the diagnosis of the immune response to COVID-19, which can help to define testing strategies against this disease.

Persistence of Hepatitis A Virus in Oysters†

2003 ◽  
Vol 66 (2) ◽  
pp. 331-334 ◽  
Author(s):  
DAVID H. KINGSLEY ◽  
GARY P. RICHARDS
Keyword(s):  
Polymerase Chain Reaction ◽  
Crassostrea Virginica ◽  
Reverse Transcription ◽  
Hepatitis A ◽  
Infectious Virus ◽  
Hepatitis A Virus ◽  
Complete Removal ◽  
Chain Reaction ◽  
Daily Feeding ◽  
Polymerase Chain

We investigated the ability of hepatitis A virus (HAV) to persist for up to 6 weeks in Eastern oysters (Crassostrea virginica). Viral RNA was detected by reverse transcription–polymerase chain reaction 6 weeks after 16 h of exposure to 90,000 PFU (180 PFU/ml of seawater) of HAV. Assaying for infectious virus in oysters that received a daily feeding of phytoplankton recovered 3,800, 650, and 500 PFU of HAV 1, 2, and 3 weeks after contamination with 90,000 PFU of HAV, respectively. However, no infectious HAV was isolated from oysters 4, 5, or 6 weeks after contamination. These results support the position that shellfish depuration is insufficient for the complete removal of infectious viruses. Extended relay times (in excess of 4 weeks) may be required to produce virologically safe shellfish.

scholarly journals Molecular typing of Clostridium perfringens isolated from swine in slaughterhouses from São Paulo State, Brazil

2012 ◽  
Vol 42 (8) ◽  
pp. 1450-1456 ◽  
Author(s):  
Thais Sebastiana Porfida Ferreira ◽  
Andrea Micke Moreno ◽  
Renata Rodrigues de Almeida ◽  
Cleise Ribeiro Gomes ◽  
Debora Dirani Sena de Gobbi ◽  
...  
Keyword(s):  
Polymerase Chain Reaction ◽  
Clostridium Perfringens ◽  
Food Poisoning ◽  
Positive Bacterium ◽  
Chain Reaction ◽  
High Prevalence ◽  
Fecal Isolate ◽  
Finishing Pig ◽  
Type C ◽  
Polymerase Chain

Clostridium perfringens is an anaerobic Gram-positive bacterium known as common pathogen for humans, for domestic and wildlife animals. Although infections caused by C. perfringens type C and A in swine are well studied, just a few reports describe the genetic relationship among strains in the epidemiological chain of swine clostridioses, as well as the presence of the microorganism in the slaughterhouses. The aim of the present study was to isolate C. perfringens from feces and carcasses from swine slaughterhouses, characterize the strains in relation to the presence of enterotoxin, alpha, beta, epsilon, iota and beta-2 toxins genes, using polymerase chain reaction (PCR) and comparing strains by means of Pulsed field gel electrophoresis (PFGE). Clostridium perfringens isolation frequencies in carcasses and finishing pig intestines were of 58.8% in both types of samples. According to the polymerase chain reaction assay, only alfa toxin was detected, being all isolates also negative to enterotoxin and beta2 toxin. Through PFGE technique, the strains were characterized in 35 pulsotypes. In only one pulsotype, the isolate from carcass sample was grouped with fecal isolate of the same animal, suggesting that the risk of cross-contamination was low. Despite the high prevalence of C. perfringens in swine carcasses from the slaughterhouses assessed, the risk of food poisoning to Brazilian pork consumers is low, since all strains were negative to cpe-gene, codifying enterotoxin.

scholarly journals USE OF THE POLYMERASE CHAIN REACTION FOR THE DIAGNOSIS OF ASYMPTOMATIC Leishmania INFECTION IN A VISCERAL LEISHMANIASIS-ENDEMIC AREA

2013 ◽  
Vol 55 (2) ◽  
pp. 101-104 ◽  
Author(s):  
Luciana Almeida Silva ◽  
Héctor Dardo Romero ◽  
Aline Fagundes ◽  
Nédia Nehme ◽  
Otávio Fernandes ◽  
...  
Keyword(s):  
Polymerase Chain Reaction ◽  
Visceral Leishmaniasis ◽  
Endemic Area ◽  
Asymptomatic Infection ◽  
Control Measures ◽  
Skin Tests ◽  
Leishmania Infection ◽  
Chain Reaction ◽  
Serological Tests ◽  
Polymerase Chain

The diagnosis of asymptomatic infection with Leishmania (Leishmania) chagasi has become more important over recent years. Expansion of visceral leishmaniasis might be associated with other routes of transmission such as transfusion, congenital or even vector transmission, and subjects with asymptomatic infection are potential reservoirs. Moreover, the identification of infection may contribute to the management of patients with immunosuppressive conditions (HIV, transplants, use of immunomodulators) and to the assessment of the effectiveness of control measures. In this study, 149 subjects living in a visceral leishmaniasis endemic area were evaluated clinically and submitted to genus-specific polymerase chain reaction (PCR), serological testing, and the Montenegro skin test. Forty-nine (32.9%) of the subjects had a positive PCR result and none of them developed the disease within a follow-up period of three years. No association was observed between the results of PCR, serological and skin tests. A positive PCR result in subjects from the endemic area did not indicate a risk of progression to visceral leishmaniasis and was not associated with a positive result in the serological tests.

scholarly journals Prevalence of Adhesion and Regulation of Biofilm-Related Genes in Different Clones ofStaphylococcus aureus

2012 ◽  
Vol 2012 ◽  
pp. 1-10 ◽  
Author(s):  
Salman Sahab Atshan ◽  
Mariana Nor Shamsudin ◽  
Zamberi Sekawi ◽  
Leslie Than Thian Lung ◽  
Rukman Awang Hamat ◽  
...  
Keyword(s):  
Polymerase Chain Reaction ◽  
Biofilm Formation ◽  
Clinical Information ◽  
Microtiter Plate ◽  
Rt Pcr ◽  
Chain Reaction ◽  
Microtiter Plate Assay ◽  
High Prevalence ◽  
Different Types ◽  
Polymerase Chain

Clinical information about genotypically different clones of biofilm-producingStaphylococcus aureusis largely unknown. We examined whether different clones of methicillin-sensitive and methicillin-resistantS. aureus(MSSA and MRSA) differ with respect to staphylococcal microbial surface components recognizing adhesive matrix molecules (MSCRAMMs) in biofilm formation. The study used 60 different types ofspaand determined the phenotypes, the prevalence of the 13 MSCRAMM, and biofilm genes for each clone. The current investigation was carried out using a modified Congo red agar (MCRA), a microtiter plate assay (MPA), polymerase chain reaction (PCR), and reverse transcriptase polymerase chain reaction (RT-PCR). Clones belonging to the samespatype were found to have similar properties in adheringto thepolystyrene microtiter plate surface. However, their ability to produce slime on MCRA medium was different. PCR experiments showed that 60 clones of MSSA and MRSA were positive for 5 genes (out of 9 MSCRAMM genes).icaADBCgenes were found to be present in all the 60 clones tested indicating a high prevalence, and these genes were equally distributed among the clones associated with MSSA and those with MRSA. The prevalence of other MSCRAMM genes among MSSA and MRSA clones was found to be variable. MRSA and MSSA gene expression (MSCRAMM andicaADBC) was confirmed by RT-PCR.

scholarly journals Effect of Screening for Methicillin-Resistant Staphylococcus aureus Carriage by Polymerase Chain Reaction on the Duration of Unnecessary Preemptive Contact Isolation

2008 ◽  
Vol 29 (11) ◽  
pp. 1077-1079 ◽  
Author(s):  
Ilker Uçkay ◽  
Hugo Sax ◽  
Anne Iten ◽  
Véronique Camus ◽  
Gesuele Renzi ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Polymerase Chain Reaction ◽  
Hospital Readmission ◽  
Quantitative Polymerase Chain Reaction ◽  
Chain Reaction ◽  
Methicillin Resistant ◽  
Contact Isolation ◽  
High Prevalence ◽  
Chromogenic Agar ◽  
Polymerase Chain

A high prevalence of methicillin-resistant Staphylococcus aureus (MRSA) carriage at hospital readmission among previous MRSA carriers warrants screening and preemptive isolation precautions. The replacement of culture on chromogenic agar with rapid quantitative polymerase chain reaction for readmission screening reduces the number of unnecessary preemptive isolation-days by 54% (from 6.88 to 3.14 isolation-days) and related costs by 45% (from US$113.2 to US$62.1) for patients who test negative for MRSA.

scholarly journals Survey of Wolbachia frequency in Nashville, Tennessee Reveals Novel Infections

2020 ◽  
Vol 17 (1) ◽  
pp. 21-29
Author(s):  
Sangami Pugazenthi ◽  
Phoebe White ◽  
Aakash Basu ◽  
Anoop Chandrashekar ◽  
Dylan Shropshire
Keyword(s):  
Polymerase Chain Reaction ◽  
Wolbachia Infection ◽  
Intracellular Bacteria ◽  
Infection Frequency ◽  
University Campus ◽  
Chain Reaction ◽  
High Prevalence ◽  
Polymerase Chain ◽  
Geographic Regions ◽  
Vanderbilt University

Wolbachia (Rickettsiales: Anaplasmataceae) are maternally transmitted intracellular bacteria that infect approximately half of all insect species. These bacteria commonly act as reproductive parasites or mutualists to enhance their transmission from mother to offspring, resulting in high prevalence among some species. Despite decades of research on Wolbachia’s global frequency, there are many arthropod families and geographic regions that have not been tested for Wolbachia. Here, arthropods were collected on the Vanderbilt University campus in Nashville, Tennessee, where Wolbachia frequency has not been previously studied. The dataset consists of 220 samples spanning 34 unique arthropod families collected on the Vanderbilt University campus. The majority of our samples were from the families Blattidae (Blattodea), Pulicidae (Siphonaptera), Dryinidae (Hymenoptera), Aphididae (Hemiptera), Paronellidae (Entomobryomorpha), Formicidae (Hymenoptera), Pseudococcidae (Hemiptera), Sphaeroceridae (Diptera), and Coccinellidae (Coleoptera). PCR-based techniques were used to assign infection states and, from these data, the first cases of Wolbachia in the Paronellidae springtails, Lithobiidae (Lithobiomorpha) centipedes, Lonchopteridae (Diptera) spear-winged flies, Sepsidae (Diptera) black scavenger flies, Cryptocercidae (Blattodea) wood roaches, and Lauxaniidae (Diptera) acalyptrate flies were identified. Within-family infection frequencies ranged from 17-100% when Wolbachia was observed; however, numerous families tested did not reveal evidence of infection. These results expand on the field’s understanding of Wolbachia’sfrequencyin Nashville, Tennessee, and among arthropod families broadly, and is the first report of Wolbachia in centipedes. KEYWORDS: Wolbachia; Infection Frequency; Endosymbiont; Tennessee; Centipede; Arthropod; Polymerase Chain Reaction; Nashville

scholarly journals Combining diagnostic procedures for the management of leishmaniasis in areas with high prevalence of Leishmania guyanensis

2011 ◽  
Vol 86 (6) ◽  
pp. 1141-1144 ◽  
Author(s):  
Ednelza de Almeida Benicio ◽  
Ellen Pricilla Nunes Gadelha ◽  
Anette Talhari ◽  
Roberto Moreira da Silva Jr ◽  
Luis Carlos Ferreira ◽  
...  
Keyword(s):  
Polymerase Chain Reaction ◽  
Diagnostic Procedures ◽  
Diagnostic Methods ◽  
Species Discrimination ◽  
Leishmania Braziliensis ◽  
Hsp 70 ◽  
Chain Reaction ◽  
High Prevalence ◽  
Polymerase Chain ◽  
Leishmania Guyanensis

BACKGROUND: The Amazon region corresponds to approximately 40% of the cases of leishmaniasis in Brazil. We report a prospective study with 180 patients conducted in a health care unit that diagnoses 10% of the cases of leishmaniasis in the Brazilian Amazon. The study addresses how a combination of procedures improves diagnosis in areas with high prevalence of Leishmania guyanensis. OBJECTIVES: to evaluate diagnostic methods in areas with high prevalence of Leishmania guyanensis. METHODS: All subjects were amastigote-positive by direct microscopic examination of lesion scarifications. We conducted skin biopsy and histopathology, polymerase chain reaction and parasite cultivation. RESULTS: Polymerase chain reaction detected almost ninety percent of infections when two amplification protocols were used (mini-exon and HSP-70). HSP-70 specific polymerase chain reaction matched the sensitivity of parasite cultivation plus histopathology. CONCLUSION: The best combination was polymerase chain reaction plus histopathology, which increased diagnostic sensitivity to 94%. Species discrimination by polymerase chain reaction disclosed prevalence of human infections with Leishmania guyanensis of 94% and with Leishmania braziliensis of 6% for this region

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