Search Results (52)

Malaria is a parasitic disease caused by Plasmodium protozoa, which is a serious public health issue in Madagascar, an island country located off the coast of Africa in the Indian Ocean. Despite significant efforts to prevent the spread of communicable diseases, the country’s epidemiological situation is worrying and has been deteriorating in recent years, mostly due to poverty and limited access to healthcare. The aim of the present study was to assess the prevalence rates of malaria in northern Madagascar, as exemplified by the Mampikony District, between 2023 and 2024, as well as to assess the effectiveness of the methods used for malaria diagnosis. Material and methods. The study was conducted on a sample of 782 local residents who reported to healthcare centres in Mampikony between 2023 and 2024. The methods used to establish the diagnosis of malaria included rapid diagnostic tests (mRDTs) and molecular assays (RT-PCRs). Results. The 2023 study conducted on a sample of 484 patients demonstrated malaria prevalence of 4.5% (by mRDTs) and 8.2% (by RT-PCR), while the 2024 study carried out on a sample of 298 patients demonstrated malaria prevalence of 8.4% (by mRDTs) and 12.4% (by RT-PCR). The analysis of demographic variables showed that malaria was more prevalent in women and in adults; however, the differences between individual study groups were not statistically significant. In this study, positive malaria cases were predominantly caused by P. falciparum, but we also found cases caused by P. vivax as well as mixed infections. Conclusions. The study results support the need to apply more sensitive diagnostic tools for malaria diagnosis, e.g., RT-PCR. Also, our findings indicate the necessity to reassess and update the strategies for the treatment of malaria in the region due to a growing asymptomatic malaria carriage. To control the spread of malaria in Madagascar, it is essential to apply a wide range of interventions. Full article

Syphilis, which is caused by Treponema pallidum, remains one of the most common congenital infection worldwide and has tremendous consequences for the mother and her developing foetus if left untreated. The complexity of the exposure to this pathogen extends beyond the well-established clinical manifestations, as it can profoundly affect placental histomorphology. This study aimed to compare T. pallidum-exposed placental villi structures with healthy placentae at term to evaluate the histomorphological differences using stereology. In this case-control study conducted at term (38 weeks ± 2 weeks), 78 placentae were collected from the hospital delivery suites, comprising 39 cases (T. pallidum-exposed) and 39 controls (non-exposed), who were gestational age-matched with other potential confounders excluded. Blood samples from the umbilical vein and placental basal plate were tested for syphilis, using rapid diagnostic test (RDT) kits for T. pallidum (TP) antibodies (IgG and IgM) to classify placentae as exposed to T. pallidum (cases) and non-exposed (controls). Tissue sections were prepared and stained with haematoxylin and eosin, and the mean volume densities of syncytial knots, foetal capillaries, syncytial denuded areas, and intervillous spaces were estimated using stereological methods. Statistical analysis was performed to compare the mean values between the case and control groups. Stereological assessment revealed significant differences between the T. pallidum-exposed and non-exposed groups with regard to syncytial knots (p < 0.0001), syncytial denudation (p < 0.0001), and foetal capillaries (p < 0.0001), but no significant difference in the intervillous space was found (p = 0.1592). Therefore, our study shows, for the first time, that the histomorphology of human placental villi appears to be altered by exposure to T. pallidum. It will, therefore, be interesting to determine whether these changes in the placental villi translate into long-term effects on the baby. Full article

Malaria remains a major public health threat in Cameroon, with an estimated 3 million new cases of Plasmodium spp. infections reported each year. The aim of this study was to assess the occurrence of Plasmodium infections in Cameroon in a group of symptomatic and asymptomatic individuals, residents of the town of Mbalmayo, located in the Central Region of Cameroon. Screening was conducted in December 2024 at the Mbalayo District Hospital. This study involved a total of 93 people aged between 1 and 70 years old, who voluntarily agreed to have their blood samples taken and tested for malaria. As part of this study, the demographic variables of the participants were taken, malaria rapid diagnostic tests (mRDTs) were performed, and blood samples were applied to the Whatman FTA cards for further real-time PCR diagnostics. The occurrence of Plasmodium infections in the residents of Mbalmayo differed depending on the diagnostic method used (30.1% with mRDT vs. 60.2% when RT-PCR assays were performed). A total of 55 malaria cases were found to be caused by P. falciparum, while one case was found to be caused by P. vivax. Nearly half of the study participants exhibited no signs or symptoms of malaria, whereas 35.7% reported fever, 17.9% respiratory symptoms, and 10.7% gastrointestinal symptoms. The prevalence of malaria remains high in populations inhabiting the Central Region in Cameroon. P. falciparum is the dominant species in the region. A considerable proportion of infected individuals are asymptomatic, which supports the finding that asymptomatic carriers play a critical role in disease transmission. The differences between the results depending on the diagnostic method used (mRDT vs. RT-PCR) suggest that there is a need to use a combination of different methods for the identification of malaria, especially in cases of low parasitemia. Full article

Horizontal curves have been a significant safety concern on roads for years, often resulting in a high incidence of crashes. A European Road Safety Observatory report indicated that 53% of road crashes in the EU in 2020 occurred on rural roads, mainly due to misjudging when navigating these curves. This study explores innovative low-cost road designs for this issue, such as the red-white pattern edge line (RWE), the solid red edge line (RE), the alternating red-white checkered median stripe (RWM), and the red dragon’s teeth (RDT) to improve driver behavior around curves. The various road markings were tested based on speed, acceleration/deceleration, and lateral position before and during horizontal curves in a driving simulator using STISIM Drive^® 3. Fifty-two volunteers, aged between 20 and 75, participated in the study. The simulation road was designed according to the Flemish Road Agency (AWV) guidelines. The simulation tested twelve horizontal curves, including left and right turns, with 125 m and 350 m radii. The results were analyzed using within-subjects repeated measures ANOVA, with Greenhouse–Geisser correction for sphericity violations. It was revealed that these markings can reduce driving speeds and improve control, enhancing road safety. Specifically, the red-white median stripe resulted in better lateral positioning. At the same time, red dragon’s teeth minimized deceleration before curves, although their effects were less significant for curves with larger radii. Full article

Malaria remains a major public health threat in Sub-Saharan Africa. According to the World Health Organization (WHO) estimates, Plasmodium falciparum species account for nearly 100% of the malaria cases occurring on the African continent. According to the Centers for Disease Control and Prevention (CDC), falciparum malaria predominates, but non-falciparum species are also present in Africa. The aim of the study was to assess the occurrence of asymptomatic malaria cases, as well as to identify Plasmodium species at two different settings with the lowest index of infections in Tanzania (according to the Tanzanian Ministry of Health < 1%), i.e., on the mainland (Arusha Region) and on the Pemba Island (Zanzibar Archipelago). The study was conducted in June 2023 and involved 722 individuals, including 449 residents of mainland Tanzania and 273 residents of the Zanzibar Archipelago. The screening consisted of two phases. In the first one, which was carried out at two different settings, i.e., in the Karatu Lutheran Hospital (Arusha Region, mainland Tanzania) and the Amal Hospital (Pemba, Zanzibar Archipelago), mRDTs (malaria rapid diagnostic tests) were performed, haemoglobin concentrations were measured, and blood samples for further molecular tests were collected onto Whatman micro cards from each of the individuals involved. In the second phase (conducted in Poland, Europe), RT-PCR tests for malaria were performed. The screening found asymptomatic Plasmodium infections in 4.2% of the study subjects from mainland Tanzania and in 4.8% from the Archipelago. The research confirmed cases of P. falciparum malaria but also found single cases of mixed infections with P. falciparum + P. malariae or P. ovale. The results demonstrated that the occurrence of malaria in northern mainland and Zanzibar Archipelago is higher than the official MoH reports present. The study findings are consistent with the reports by CDC, which suggest that non-falciparum species are also present in Sub-Saharan Africa. Full article

To study the dynamic response of multi-span mortise and tenon stone bridges under natural excitation, a bluestone multi-span stone bridge with a main span of 2.56 m in southern China was taken as the research object. Based on the collected pulsating signals of bridge piers and slabs, the natural frequencies and damping ratios of the main span bridge slab and pier were analyzed using the half-power broadband method (HPBM) and random decrement technique (RDT). Modal analysis was conducted using ANSYS, and the results were compared with those obtained from on-site experiments for further performance analysis. The research results of this article indicate that the natural frequency range of the 2.56-m bridge slab identified by measured signals is 48–49 Hz, and the damping ratio range is 33.33–36.61%. The natural frequency of the central pier is 75–76 Hz, and the damping ratio range is 26.39–27.83%. Through finite element modal analysis, the natural frequency of the bridge slab is 54.401 Hz, with an error of 10.5%. The natural frequency of the overall stone bridge is about 82.2 Hz, with an error of about 8.2%. The validated finite element model was subjected to normal water flow impact and erosion simulation. The results indicate that under erosion with fewer particles and lower flow rates, the upstream pier bottom at the center receives the highest relative erosion mass and displacement per unit area. The bridge deck near the main span also experienced relative displacement. Therefore, in the subsequent protection work, special attention should be paid to these components. Full article

Malaria is a significant health problem in Africa, primarily due to the Plasmodium falciparum species, but this is not the only etiological factor responsible for malaria on the continent. The goal of the present research was to describe asymptomatic malaria cases and to identify Plasmodium species responsible for malaria in the BaAka Pygmies, inhabitants of the Central African Republic (CAR). Screening was realised in the period of August–September 2021 among 308 people, including 74 children and 234 adults reporting to a healthcare facility in Monasao (southwest CAR), an area inhabited by a semi-nomadic tribe of BaAka Pygmies. The study consisted of two phases. Phase I, which was conducted in Africa, consisted of performing malaria rapid diagnostic tests (mRDTs), taking haemoglobin measurements and collecting blood samples onto Whatman FTA cards for molecular diagnostics. Phase II, which was conducted in Poland, involved molecular tests (RT-PCR) to confirm or rule out malaria infections and to identify Plasmodium species responsible for the infections. mRDTs detected Plasmodium infections in 50.3% of children and 17.1% of adults participating in the study, whereas RT-PCR assays yielded positive results for 59.5% children and 28.6% adults. Molecular tests detected multiple Plasmodium falciparum infections but also three infections with P. malariae, three with P. ovale and one with P. vivax. The obtained results have confirmed numerous asymptomatic Plasmodium infections among the BaAka Pygmies. The rates of asymptomatic malaria cases in adults were twice as high as those in children, which may be indicative of the gradual acquisition of protective immunity with age. The study findings have also demonstrated that although most cases of malaria in Africa are caused by P. falciparum, three other species are also present in the region. Full article

Introduction: Radiotherapy (RT) shows potential for improving local control in cases of oligoprogressive metastatic breast cancer (mBC). This retrospective analysis aims to evaluate the advantages of RT in such a clinical scenario. Methods: We conducted a retrospective analysis including patients with mBC who received radiation therapy (RT) for up to three sites of oligoprogression while continuing systemic therapy. The study took place between January 2014 and December 2021. Our endpoints were progression-free survival after radiotherapy (PFS-AR), the rate of discontinuation of systemic therapy (RDT) at three months post-RT, and overall survival (OS). We used Cox regression analysis to perform multivariate analysis for PFS-AR. Results: Fifty-nine patients met the inclusion criteria. The PFS-AR was 13 months (95% CI 8.5–18.8 months). At three months, the RDT was 3% (two patients). A significant difference in median PFS-AR was observed between patients in the first + second-line group and those in the subsequent line group (p = 0.03). In the multivariate analysis conducted for PFS-AR, the biologically effective dose (BED) with α/β = 4 > 100 Gy emerged as the sole significant variable (p = 0.0017). The median overall survival (OS) was 24.4 months (95% CI 17–24.4 months). Conclusions: This study is the first report on the outcomes of radiotherapy in a cohort of over 50 patients with oligoprogressive metastatic breast cancer (mBC). Our findings emphasize the significant relationship between PFS-AR, the number of ongoing lines of systemic therapy, and the BED of radiotherapy. Full article

Efforts to control and eliminate measles and rubella are aided by high-quality surveillance data—supported by laboratory confirmation—to guide decision-making on routine immunization strategies and locations for conducting preventive supplementary immunization activities (SIAs) and outbreak response. Important developments in rapid diagnostic tests (RDTs) for measles and rubella present new opportunities for the global measles and rubella surveillance program to greatly improve the ability to rapidly detect and respond to outbreaks. Here, we review the status of RDTs for measles and rubella Immunoglobulin M (IgM) testing, as well as ongoing questions and challenges regarding the operational use and deployment of RDTs as part of global measles and rubella surveillance. Efforts to develop IgM RDTs that can be produced at scale are underway. Once validated RDTs are available, clear information on the benefits, challenges, and costs of their implementation will be critical for shaping deployment guidance and informing country plans for sustainably deploying such tests. The wide availability of RDTs could provide new programmatic options for measles and rubella elimination efforts, potentially enabling improvements and flexibility for testing, surveillance, and vaccination. Full article

The purpose of this work was to test a new setup to pump water with entrained air for application in gas fermentation. A mixed flow, where gas is contained in a liquid to be pumped, rapidly reduces the efficiency of a conventional pump, due to the compressibility of the gas. It is not always possible to degas the fluid, for instance in gas fermentation, which is preferably carried out in tubular reactors (loop fermenters) to achieve a high conversion rate of the gaseous feedstocks. Method: In this work, a rim-driven thruster (RDT) was tested in a lab-scale, cold flow model of a loop reactor with 5–30% (by volume) of gas fraction (air) in the liquid (water) as alternative propulsion element (6 m total pipe length, ambient temperature and pressure). As a result, it was found that the RDT, in connection with a guiding vane providing swirling motion to the two-phase fluid, could pump a mixed flow with up to 25.7% of gas content (by volume) at atmospheric pressure and 25 °C and 0.5 to 2 m/s flow speed. In conclusion, an RDT is advantageous over a classic propulsion element like a centrifugal pump or axial flow pump for transporting liquids with entrained gases. This article describes the potential of rim-driven thrusters, as known from marine propulsion, in biotechnology, the chemical industry, and beyond, to handle multiphase flows. Full article

Staphylococcus aureus bacteraemia (SAB) is a life-threatening bloodstream infection. Improved adherence to quality-of-care indicators (QCIs) can significantly enhance patient outcomes. This quasi-experimental study evaluated the impact of a bundle of interventions on QCI adherence in adult patients with SAB. Additionally, a molecular rapid diagnostic test (mRDT) for S. aureus and methicillin resistance was introduced during weekdays. We compared pre-intervention (January–December 2022) and post-intervention (May 2023–April 2024) data on QCI adherence and time to appropriate treatment. A total of 56 and 40 SAB episodes were included in the pre- and post-intervention periods, respectively. Full QCI adherence significantly increased from 28.6% to 67.5% in the post-intervention period (p < 0.001). The mRDT diagnosed SAB in eight cases (26.6%), but the time to achieve appropriate target therapy did not improve in the post-intervention period (54 h (IQR 30–74) vs. 72 h (IQR 51–83), p = 0.131). The thirty-day mortality rate was comparable between the two periods (17.9% vs. 12.5%, p = 0.476). This study demonstrates that a bundle of interventions can substantially improve adherence to SAB management QCIs. Full article

In bacteria, the Rho protein mediates Rho-dependent termination (RDT) by identifying a non-specific cytosine-rich Rho utilization site on the newly synthesized RNA. As a result of RDT, downstream RNA transcription is reduced. Due to the bias in reverse transcription and PCR amplification, we could not identify the RDT site by directly measuring the amount of mRNA upstream and downstream of RDT sites. To overcome this difficulty, we employed a 77 bp reporter gene argX, (coding tRNA^arg) from Brevibacterium albidum, and we transcriptionally fused it to the sequences to be assayed. We constructed a series of plasmids by combining a segment of the galactose (gal) operon sequences, both with and without the RDT regions at the ends of cistrons (galE, galT, and galM) upstream of argX. The RNA polymerase will transcribe the gal operon sequence and argX unless it encounters the RDT encoded by the inserted sequence. Since the quantitative real-time PCR (qRT-PCR) method detects the steady state following mRNA synthesis and degradation, we observed that tRNA^arg is degraded at the same rate in these transcriptional fusion plasmids. Therefore, the amount of tRNA^arg can directly reflect the mRNA synthesis. Using this approach, we were able to effectively assay the RDTs and Rho-independent termination (RIT) in the gal operon by quantifying the relative amount of tRNA^arg using qRT-PCR analyses. The resultant RDT% for galET, galTK, and at the end of galM were 36, 26, and 63, individually. The resultant RIT% at the end of the gal operon is 33%. Our findings demonstrate that combining tRNA^arg with qRT-PCR can directly measure RIT, RDT, or any other signal that attenuates transcription efficiencies in vivo, making it a useful tool for gene expression research. Full article

Hepatitis B e antigen (HBeAg) is a marker of wild-type hepatitis B virus replication. In resource-limited countries where access to enzyme-linked immunosorbent assay (ELISA) remains a challenge, rapid diagnostic tests (RDT) constitute a good alternative. The HBeAg status is employed to evaluate eligibility for antiviral therapy and to prevent the transmission of hepatitis B from mother to child (PMTCT). The objective of this study was to assess the diagnostic performance of the SD-Bioline^®HBeAg RDT commonly used for detecting HBeAg in laboratories in Burkina Faso. The sample panel used was collected from HBsAg-positive patients received in the laboratory for the detection of HBeAg with the rapid test. The samples were retested for HBeAg using the VIDAS HBe/Anti-HBe enzyme-linked fluorescent assay (ELFA) (Gold standard). Then, the viral load (VL) of HBV DNA was determined using the GENERIC HBV CHARGE VIRLAE kit (GHBV-CV). The diagnostic performances of the SD-Bioline^®HBeAg and its agreement with the gold standard were calculated with their 95% confidence intervals. Overall, 340 sera obtained from HBsAg-positive patients were included in this evaluation Compared to the VIDAS HBe/Anti-HBe ELFA test, the sensitivity (Se) and specificity (Sp) of the SD-Bioline^®HBeAg test were 33.3% and 97.9%, respectively. The concordance between the two tests was 0.42. Depending on the viral load, the Se and Sp varied from 8.8% and 98.3% for a VL < 2000 IU/mL to 35.5% and 98.4% for a VL > 2,000,000 IU/mL. The results showed a low sensibility of the SD-Bioline^®HBeAg RDT test, indicating that its use is inappropriate for the clinical management of HBV-infected patients. They also highlight the urgent need to develop HBeAg rapid tests with better sensitivities. Full article

SARS-CoV-2 diagnostic tests have become an important tool for pandemic control. Among the alternatives for COVID-19 diagnosis, antigen rapid diagnostic tests (Ag-RDT) are very convenient and widely used. However, as SARS-CoV-2 variants may continuously emerge, the replacement of tests and reagents may be required to maintain the sensitivity of Ag-RDTs. Here, we describe the development and validation of an Ag-RDT during an outbreak of the Omicron variant, including the characterization of a new monoclonal antibody (anti-DTC-N 1B3 mAb) that recognizes the Nucleocapsid protein (N). The anti-DTC-N 1B3 mAb recognized the sequence TFPPTEPKKDKKK located at the C-terminus of the N protein of main SARS-CoV-2 variants of concern. Accordingly, the Ag-RDT prototypes using the anti-DTC-N 1B3 mAB detected all the SARS-CoV-2 variants—Wuhan, Alpha, Gamma, Delta, P2 and Omicron. The performance of the best prototype (sensitivity of 95.2% for samples with Ct ≤ 25; specificity of 98.3% and overall accuracy of 85.0%) met the WHO recommendations. Moreover, results from a patients’ follow-up study indicated that, if performed within the first three days after onset of symptoms, the Ag-RDT displayed 100% sensitivity. Thus, the new mAb and the Ag-RDT developed herein may constitute alternative tools for COVID-19 point-of-care diagnosis and epidemiological surveillance. Full article

In Senegal, the burden of dengue is increasing and expanding. As case management and traditional diagnostic techniques can be difficult to implement, rapid diagnostic tests (RDTs) deployed at point of care are ideal for investigating active outbreaks. The aim of this study was to evaluate the diagnostic performance of the Dengue NS1 and Dengue IgM/IgG RDTs on the serum/plasma samples in a laboratory setting and in the field. During laboratory evaluation, performance of the NS1 RDT was assessed using NS1 ELISA as the gold standard. Sensitivity and specificity were 88% [75–95%] and 100% [97–100%], respectively. Performance of the IgM/IG RDT was assessed using the IgM Antibody Capture (MAC) ELISA, indirect IgG, and PRNT as gold standards. The IgM and IgG test lines respectively displayed sensitivities of 94% [83–99%] and 70% [59–79%] and specificities of 91% [84–95%] and 91% [79–98%]. In the field, the Dengue NS1 RDT sensitivity and specificity was 82% [60–95%] and 75% [53–90%], respectively. The IgM and IgG test lines displayed sensitivities of 86% [42–100%] and 78% [64–88%], specificities of 85% [76–92%] and 55% [36–73%], respectively. These results demonstrate that RDTs are ideal for use in a context of high prevalence or outbreak setting and can be implemented in the absence of a confirmatory test for acute and convalescent patients. Full article