diagnostic assays
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The Analyst ◽  
2022 ◽  
Author(s):  
Marimuthu Citartan

The direct modulation of a light-up aptamer that engenders an analyte-specific aptamer-light-up aptamer chimera is readily applicable in any diagnostic assay for a targeted detection.


2022 ◽  
pp. 58-77
Author(s):  
Mohamed Echchakery ◽  
Samia Boussaa ◽  
Souad El Mouahid ◽  
Maryam Mountassir ◽  
Said El Hizazi ◽  
...  

The coronavirus disease 2019 (COVID-19) which has become the pandemic par excellence of our time places pressure on various aspects of human endeavor and as such requires detailed study to better combat it. However, diagnostic tests were used to provide data on the incidence of COVID-19 and to assess the immune status of infected individuals. The objective of this chapter is to describe the diagnostic methods currently used to identify SARS-CoV-2 infection. Obtaining the first SARS-CoV-2 genome sequence was decisive for the development of molecular diagnostic assays that currently make it possible to diagnose and screen for the Sars-CoV-2 infection. Their uses depend on the target to be detected. Antigenic tests detect the presence of a virus antigen, which usually makes a proteinaceous part of the virus surface. The serology tests detect the presence of antibodies generated against SARS-CoV-2 and are also a relevant tool for epidemiological studies.


Talanta ◽  
2022 ◽  
pp. 123217
Author(s):  
Rui Mao ◽  
Tianzuo Wang ◽  
Yue Zhao ◽  
Xinyao Wu ◽  
Shun Zhang ◽  
...  

Author(s):  
Carmen Sara Hernández-Rodríguez ◽  
Sara Moreno-Martí ◽  
Gabrielle Almecija ◽  
Krisztina Christmon ◽  
Josephine D. Johnson ◽  
...  

AbstractVarroa destructor is considered a major reason for high loss rate of Western honey bee (Apis mellifera) colonies. To prevent colony losses caused by V. destructor, it is necessary to actively manage the mite population. Beekeepers, particularly commercial beekeepers, have few alternative treatments other than synthetic acaricides to control the parasite, resulting in intensive treatment regimens that led to the evolution of resistance in mite populations. To investigate the mechanism of the resistance to amitraz detected in V. destructor mites from French and U.S. apiaries, we identified and characterized octopamine and tyramine receptors (the known targets of amitraz) in this species. The comparison of sequences obtained from mites collected from different apiaries with different treatment regimens, showed that the amino acid substitutions N87S or Y215H in the OctβR were associated with treatment failures reported in French or U.S. apiaries, respectively. Based on our findings, we have developed and tested two high throughput diagnostic assays based on TaqMan technology able to accurately detect mites carrying the mutations in this receptor. This valuable information may be of help for beekeepers when selecting the most suitable acaricide to manage V. destructor.


Animals ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 12
Author(s):  
Sanaa M. Idris ◽  
Kamal H. Eltom ◽  
Julius B. Okuni ◽  
Lonzy Ojok ◽  
Wisal A. Elmagzoub ◽  
...  

Paratuberculosis (PTB) is a contagious and chronic enteric disease of ruminants and many non-ruminants caused by Mycobacterium avium subsp. paratuberculosis (MAP), and is characterised by diarrhoea and progressive emaciation with consequent serious economic losses due to death, early culling, and reduced productivity. In addition, indirect economic losses may arise from trade restrictions. Besides being a production limiting disease, PTB is a potential zoonosis; MAP has been isolated from Crohn’s disease patients and was associated with other human diseases, such as rheumatoid arthritis, Hashimoto’s thyroiditis, Type 1 diabetes, and multiple sclerosis. Paratuberculosis in sheep and goats may be globally distributed though information on the prevalence and economic impact in many developing countries seem to be scanty. Goats are more susceptible to infection than sheep and both species are likely to develop the clinical disease. Ingestion of feed and water contaminated with faeces of MAP-positive animals is the common route of infection, which then spreads horizontally and vertically. In African countries, PTB has been described as a “neglected disease”, and in small ruminants, which support the livelihood of people in rural areas and poor communities, the disease was rarely reported. Prevention and control of small ruminants’ PTB is difficult because diagnostic assays demonstrate poor sensitivity early in the disease process, in addition to the difficulties in identifying subclinically infected animals. Further studies are needed to provide more insight on molecular epidemiology, transmission, and impact on other animals or humans, socio-economic aspects, prevention and control of small ruminant PTB.


2021 ◽  
Author(s):  
Yanxia Bei ◽  
Kyle B. Vrtis ◽  
Janine G. Borgaro ◽  
Bradley W. Langhorst ◽  
Nicole M. Nichols

The emergence of new SARS-CoV-2 variants necessitates the reevaluation of current COVID-19 tests to ensure continued accuracy and reliability. The new SARS-CoV-2 variant, Omicron, is heavily mutated, with over 50 mutations within its RNA genome. Any of these mutations could adversely affect the ability of diagnostic assays to detect the virus in patient samples, potentially leading to inconclusive or false negative results. In fact, the U.S. Food and Drug Administration (FDA) has identified over two dozen diagnostic tests that contain a gene target that is expected to have significantly reduced sensitivity due to a mutation in the SAS-CoV-2 Omicron variant1. Additionally, one of the U.S. Centers for Disease Control and Prevention (CDC) Emergency Use Authorization (EUA) targets for COVID-19 tests, 2019-nCoV_N1, overlaps an Omicron mutation within the sequence targeted by the fluorescent probe. This target from the CDC has been used in many other EUA assays. Using in vitro transcribed (IVT) N gene RNA representing the wild-type (GenBank/GISAID ID MN908947.3) and Omicron variant (BA.1, GISAID ID EPI_ISL_6752027), we evaluated the performance of two different amplification protocols, both of which include the CDC 2019-nCoV_N1 primer-probe set. Both assays were able to detect the mutant N1 sequence as efficiently as the wild-type sequence. Consequently, these data suggest that diagnostic assays that use the 2019-nCoV-N1 primer-probe set are unlikely to be impacted by currently circulating Omicron lineage viruses.


2021 ◽  
Vol 9 (12) ◽  
pp. 2596
Author(s):  
Narda Medina ◽  
Juan Luis Rodriguez-Tudela ◽  
Luis Aguirre ◽  
Luis R. Salazar ◽  
Osmar Gamboa ◽  
...  

Among people with HIV, histoplasmosis represents an important cause of mortality. Previous studies provided estimates of the disease incidence. Here, we compared those estimates with the results obtained from a screening program implemented in Guatemala, which included histoplasmosis detection for people with HIV. To compare the results of this program with previous estimations, a literature search was performed and reports concerning histoplasmosis incidence were analyzed. The screening program enrolled 6366 patients. The overall histoplasmosis incidence in the screening program was 7.4%, which was almost double that estimated in previous studies. From 2017 to 2019, the screening program showed an upward trend in histoplasmosis cases from 6.5% to 8.8%. Histoplasmosis overall mortality among those who were newly HIV diagnosed showed a decrease at 180 days from 32.8% in 2017 to 21.2% in 2019. The screening approach using rapid diagnostic assays detects histoplasmosis cases more quickly, allowing a specific treatment to be administered, which decreases the mortality of the disease. Therefore, the use of these new techniques, especially in endemic areas of histoplasmosis, must be implemented.


Plant Disease ◽  
2021 ◽  
Author(s):  
Hannah M. Rivedal ◽  
Cassandra Funke ◽  
Kenneth Frost

Hemp (Cannabis sativa) acreage in Oregon has increased by approximately 240 times in the last five years and a greater number of hemp diseases have been observed. This special report documents pathogens, particularly those causing virus and virus-like diseases, that have been detected from field and greenhouse-grown hemp crops in Oregon, based on plant samples submitted to the Hermiston Agricultural Research and Extension Center Plant Clinic of Oregon State University in 2019 and 2020. Symptoms and signs were used to evaluate disease types and determine diagnostic assays used on each submission. Plants with signs or symptoms of fungal or oomycete infection were cultured to isolate pathogenic organisms and plants with symptoms suspected to be caused by virus infection were assayed for the presence of Beet curly top virus (BCTV), viroids, and phytoplasmas using polymerase chain reaction (PCR), or reverse transcription (RT)-PCR. Diseases with fungal or oomycete, and virus causes accounted for 26.5%, and 42.9% of submissions, respectively; co-infection of viral and fungal or oomycete pathogens were detected from 6.1% of submissions between 2019 and 2020. BCTV, a curtovirus, and hop latent viroid (HLVd) were the predominant pathogens detected from field and indoor grown hemp. Worland-like strains of BCTV represented 93% of all curtovirus detections. Eighty percent of HLVd detections occurred from plants that originated from indoor growing facilities. Based on BCTV vector, beet leafhopper, prevalence, field-grown hemp in western production regions may be affected by curly top and increasing hemp acreage in the landscape may have potential implications on other crops affected by curtoviruses. Virus and virus-like diseases could be a limiting factor for hemp production in some regions of the United States.


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