Seroprevalence of the Serological Markers of Transfusion-Transmissible Infections among Volunteer Blood Donors of Kosti Obstetrics and Gynecology Hospital

Background: Transfusion-transmissible infections are well-known global health challenges. The present study is proposed to investigate the seropositivity of anti-HIV1/2, anti-HCV, HBsAg, and anti-T.pallidum among volunteer blood donors of Kosti Obstetrics and Gynecology Hospital. Methods: Our study was conducted in a cross-sectional retrospective manner. The data of donors who attended Kosti Obstetrics and Gynecology Hospital throughout 2016 to 2018 were reviewed and retrieved manually from blood bank records. Results: Out of 8139 donors, 22.52% were seropositive for serological markers of TTIs and 1.67% were seropositive for at least two serological markers of TTIs. The overall seropositivity rate of anti-HIV1/2, HBsAg, anti-HCV, and anti-T.pallidum was 1.77%, 6.07%, 1.14%, and 11.87%, respectively (p < 0.000). Anti-T.pallidum was the most frequently detected (p < 0.000) marker across all study variables. TTIs seroprevalence was significantly (p < 0.000) varied according to the age, residence, occupations, and blood groups. Notably, there was a rising trend in the rate of anti-HIV1/2 and seropositivity for more than one marker with age (p < 0.000). Regionally, rural area residents had a higher rate of anti-HIV1/2 (2.20%), HBsAg (6.31%), anti-HCV (1.42%), anti-T.pallidum (18.38%), and multiple markers seropositivity (2.28%) compared to urban areas. Between occupations, the highest rate of anti-HIV1/2 (p = 0.497), HBsAg (p = 0.003), anti-HCV (p = 0.385), anti-T.pallidum (p < 0.000), and multiple markers seropositivity (p < 0.000) were detected in farmers. Regarding the screening, we also found that the frequency of anti-T.pallidum was significantly (p = 0.004) higher in donors that carry the AB+ve blood group, whereas anti-HCV (1.83%) was more frequent in O−ve blood groups (p = 0.004). Anti-T.pallidum+HBsAg was the most frequently (1.22%) co-occurring marker. In contrast, anti-T.pallidum+anti-HIV1/2+HBsAg was the lowest frequency marker (p < 0.000). Conclusions: The study showed an alarming rate of TTIs, which suggests the requirement for comprehensive surveillance and health education programs.

Evaluating the performance of DNA metabarcoding for assessment of zooplankton communities in Western Lake Superior using multiple markers

For DNA metabarcoding to attain its potential as a community assessment tool, we need to better understand its performance versus traditional morphological identification and work to address any remaining performance gaps in incorporating DNA metabarcoding into community assessments. Using fragments of the 18S nuclear and 16S mitochondrial rRNA genes and two fragments of the mitochondrial COI marker, we examined the use of DNA metabarcoding and traditional morphological identification for understanding the diversity and composition of crustacean zooplankton at 42 sites across western Lake Superior. We identified 51 zooplankton taxa (genus or species, depending on the finest resolution of the taxon across all identification methods), of which 17 were identified using only morphological traits, 13 using only DNA and 21 using both methods. The taxa found using only DNA metabarcoding included four species and one genus-level identification not previously known to occur in Lake Superior, the presence of which still needs to be confirmed. A substantial portion of taxa that were identified to genus or species by morphological identification, but not identified using DNA metabarcoding, had zero (“no record”) or &lt; 2 (“underrepresented records”) reference barcodes in the BOLD or NCBI databases (63% for COI, 80% for 16S, 74% for 18S). The two COI marker fragments identified the most genus- and species-level taxa, whereas 18S was the only marker whose family-level percent sequence abundance patterns showed high correlation to composition patterns from morphological identification, based on a NMDS analysis of Bray-Curtis similarities. Multiple replicates were collected at a subset of sites and an occupancy analysis was performed, which indicated that rare taxa were more likely to be detected using DNA metabarcoding than traditional morphology. Our results support that DNA metabarcoding can augment morphological identification for estimating zooplankton diversity and composition of zooplankton over space and time, but may require use of multiple markers. Further addition of taxa to reference DNA databases will improve our ability to use DNA metabarcoding to identify zooplankton and other invertebrates in aquatic surveys.

Systematic review of Plasmodium falciparum and Plasmodium vivax polyclonal infections: Impact of prevalence, study population characteristics, and laboratory procedures

Multiple infections of genetically distinct clones of the same Plasmodium species are common in many malaria endemic settings. Mean multiplicity of infection (MOI) and the proportion of polyclonal infections are often reported as surrogate marker of transmission intensity, yet the relationship with traditional measures such as parasite prevalence is not well understood. We have searched Pubmed for articles on P. falciparum and P. vivax multiplicity, and compared the proportion of polyclonal infections and mean MOI to population prevalence. The impact of the genotyping method, number of genotyping markers, method for diagnosis (microscopy/RDT vs. PCR), presence of clinical symptoms, age, geographic region, and year of sample collection on multiplicity indices were assessed. For P. falciparum, 153 studies met inclusion criteria, yielding 275 individual data points and 33,526 genotyped individuals. The proportion of polyclonal infections ranged from 0–96%, and mean MOI from 1–6.1. For P. vivax, 54 studies met inclusion criteria, yielding 115 data points and 13,325 genotyped individuals. The proportion of polyclonal infections ranged from 0–100%, and mean MOI from 1–3.8. For both species, the proportion of polyclonal infections ranged from very low to close to 100% at low prevalence, while at high prevalence it was always high. Each percentage point increase in prevalence resulted in a 0.34% increase in the proportion of polyclonal P. falciparum infections (P<0.001), and a 0.78% increase in the proportion of polyclonal P. vivax infections (P<0.001). In multivariable analysis, higher prevalence, typing multiple markers, diagnosis of infections by PCR, and sampling in Africa were found to result in a higher proportion of P. falciparum polyclonal infections. For P. vivax, prevalence, year of study, typing multiple markers, and geographic region were significant predictors. In conclusion, polyclonal infections are frequently present in all settings, but the association between multiplicity and prevalence is weak.

Virtual Marker Technique to Enhance User Interactions in a Marker-Based AR System

In marker-based augmented reality (AR) systems, markers are usually relatively independent and predefined by the system creator in advance. Users can only use these predefined markers to complete the construction of certain specified content. Such systems usually lack flexibility and cannot allow users to create content freely. In this paper, we propose a virtual marker technique to build a marker-based AR system framework, where multiple AR markers including virtual and physical markers work together. Information from multiple markers can be merged, and virtual markers are used to provide user-defined information. We conducted a pilot study to understand the multi-marker cooperation framework based on virtual markers. The pilot study shows that the virtual marker technique will not significantly increase the user’s time and operational burdens, while actively improving the user’s cognitive experience.

Novel approach for quantification of multiple immunofluorescent signals using histograms and 2D plot profiling of whole-section panoramic images

We describe a novel approach for quantification and colocalization of immunofluorescence (IF) signals of multiple markers on high-resolution panoramic images of serial histological sections utilizing standard staining techniques and readily available software for image processing and analysis. Human gingiva samples stained with primary antibodies against the common leukocyte antigen CD45 and factors related to heparan sulfate glycosaminoglycans (HS GAG) were used. Expression domains and spatial gradients of IF signals were quantified by histograms and 2D plot profiles, respectively. The importance of histomorphometric profiling of tissue samples and IF signal thresholding is elaborated. This approach to quantification of IF staining utilizes pixel (px) counts and comparison of px grey value (GV) or luminance. No cell counting is applied either to determine the cellular content of a given histological section nor the number of cells positive to the primary antibody of interest. There is no selection of multiple Regions-Of-Interest (ROIs) since the entire histological section is quantified. Although the standard IF staining protocol is applied, the data output enables colocalization of multiple markers (up to 30) from a given histological sample. This can serve as an alternative for colocalization of IF staining of multiple primary antibodies based on repeating cycles of staining of the same histological section since those techniques require non standard staining protocols and sophisticated equipment that can be out of reach for small laboratories in academic settings. Combined with the data from ontological bases, this approach to quantification of IF enables creation of in silico virtual disease models.

Systematic review of Plasmodium falciparum and Plasmodium vivax polyclonal infections: Impact of prevalence, study population characteristics, and laboratory procedures

Multiple infections of genetically distinct clones of the same Plasmodium species are common in many malaria endemic settings. Mean multiplicity of infection (MOI) and the proportion of polyclonal infections are often reported as surrogate marker of transmission intensity, yet the relationship with traditional measures such as parasite prevalence is not well understood. We have searched Pubmed for articles on P. falciparum and P. vivax multiplicity, and compared the proportion of polyclonal infections and mean MOI to population prevalence. The impact of the genotyping method, number of genotyping markers, method for diagnosis (microscopy/RDT vs. PCR), presence of clinical symptoms, age, geographic region, and year of sample collection on multiplicity indices were assessed. For P. falciparum, 153 studies met inclusion criteria, yielding 275 individual data points and 33526 genotyped individuals. The proportion of polyclonal infections ranged from 0-96%, and mean MOI from 1-6.1. For P. vivax, 54 studies met inclusion criteria, yielding 115 data points and 13325 genotyped individuals. The proportion of polyclonal infections ranged from 0-100%, and mean MOI from 1-3.8. For both species, the proportion of polyclonal infections ranged from very low to close to 100% at low prevalence, while at high prevalence it was always high. Each percentage point increase in prevalence resulted in a 0.34% increase in the proportion of polyclonal P. falciparum infections (P<0.001), and a 0.78% increase in the proportion of polyclonal P. vivax infections (P<0.001). In multivariable analysis, higher prevalence, typing multiple markers, diagnosis of infections by PCR, and sampling in Africa were found to result in a higher proportion of P. falciparum polyclonal infections. For P. vivax, prevalence, year of study, typing multiple markers, and geographic region were significant predictors. In conclusion, polyclonal infections are frequently present in all settings, but the association between multiplicity and prevalence is weak.

The use of multiple markers and internal positive controls significantly improves species eDNA detection rates and data reliability

In recent years, environmental DNA analyses became increasingly integrated to detect and monitor the presence and abundance of rare organisms, especially in inaccessible aquatic habitats. Although it is generally proven that detection probabilities of eDNA surveys exceed those obtained via conventional techniques, these molecular approaches are, however, also subjected to detection limitations and levels of uncertainty. Besides improvements that can be made in terms of sampling design, volumes of filtered water, and the effective quantity of DNA that is finally analysed, the sensitivity of eDNA surveys is inherently determined by the number of target eDNA copies suspended in the water column. Here we show that multiplexing different primer/probe assays for the same species, but targeting amplicons situated at different loci, is a surprisingly overlooked aspect that can substantially contribute to reduce these limitations and increase the sensitivity of single-species detections. By empirically testing a large number of natural eDNA samples via ddPCR, we reveal that the use of multiple markers can significantly lower the LOD and LOQ of rare and elusive species, such as the invasive American bullfrog and the endangered European weather loach in a variety of different water bodies, such as ponds, lakes, streams, canals, etc. Especially at very low eDNA concentrations of both target species, our results showed that analysing mulitple loci significantly increased detection probabilities and lowered stochasticity effects, and thus ultimately reduces PCR costs when analysed in multiplex. The validation and use of more than one assay taregtting a single species, may further increase the confidence of positive detections. Finally, we illustrate that the implementation of internal positive controls (IPC's), is an absolute must for accurate validation of eDNA workflows and reliable interpretation of the generated data. IPC’s not only help to track down degraded and inhibited samples, to avoid false-negative detections, it also offers insights into extraction efficiency, indispensable for accurate quantification of population densities. Overall, our findings provide strong support that the multiplexing of multiple markers on different loci in combination with the use of internal positive controls ensures increased detection rates at very low eDNA concentrations and generates more robust and reliable data.