Search Results (802)

Porcine respiratory disease is a significant economic problem for the global swine industry. Haemophilus parasuis (H. parasuis), Streptococcus suis (S. suis), and Pasteurella multocida (P. multocida) are three important pathogenic bacteria of the swine respiratory tract. Notably, the three pathogens not only frequently manifest as mixed infections, but their striking clinical similarities also present difficulties for pig populations in terms of disease prevention and treatment. Thus, we developed a triplex real-time quantitative polymerase chain reaction (qPCR) assay based on a TaqMan probe for the detection of H. parasuis, S. suis serotype 2, and P. multocida. Primers and probes were designed to target the conserved regions of the H. parasuis OmpP2 gene, the S. suis serotype 2 gdh gene, and the P. multocida Kmt1 gene. By optimizing the reaction system and conditions, a triplex qPCR method for simultaneous detection of H. parasuis, S. suis serotype 2, and P. multocida was successfully established. The amplification efficiencies of the standard curves for all three pathogens were found to be highly similar, with values of 102.105% for H. parasuis, 105.297% for S. suis serotype 2, and 104.829% for P. multocida, and all R² values achieving 0.999. The specificity analysis results showed that the triplex qPCR method had a strong specificity. The sensitivity test results indicated that the limit of detection can reach 50 copies/μL for all three pathogens. Both intra- and inter-assay coefficients of variation for repeatability were below 1%. This triplex qPCR method was shown to have good specificity, sensitivity, and reproducibility. Finally, the triplex qPCR method established in this study was compared with the nested PCR as recommended by the Chinese national standard (GB/T34750-2017) for H. parasuis, the PCR as recommended by the Chinese national standard (GB/T 19915.9-2005) for S. suis serotype 2, and the PCR as recommended by the Chinese agricultural industry standard (NY/T 564-2016) for P. multocida by detecting the same clinical samples. Both methods are reasonably consistent, while the triplex qPCR assay was more sensitive. In summary, triplex qPCR serves not only as a rapid and accurate detection and early prevention method for these pathogens but also constitutes a robust tool for microbial quality control in specific pathogen-free pigs. Full article

We developed and evaluated a semi-nested PCR assay for the detection of Babesia aktasi infection in goats based on the sequence of the B. aktasi 18S ribosomal RNA gene. Following in silico screening, the specificity of the primers was assessed using reference DNA samples, including B. ovis, B. motasi, B. crassa, B. venatorum, B. divergens, B. capreoli, Theileria ovis, and T. annulata. To determine the sensitivity of the method, blood infected with 2% parasitemia of B. aktasi was diluted to 10-fold serial dilutions. The method specifically amplified a 438 bp fragment of B. aktasi DNA, but did not demonstrate cross-amplification with the other hemoparasites tested. The sensitivity assay indicated that this PCR method was able to detect infection at a dilution of 10⁻⁸ of 2% parasitemia (0.074 parasites/200 µL). Ninety-seven blood samples collected from goats were used to analyze for B. aktasi, and the infection was detected in 18.5% of the goats. Additionally, the method was also applied to 44 field DNA samples that were detected to be positive for B. aktasi by reverse line blotting (RLB), and showed 84.1% agreement. The findings revealed that newly developed semi-nested PCR can detect B. aktasi infections in goats with high sensitivity and specificity. Full article

The CO₂ adsorption capacity and the CO₂/N₂ selectivity of a series of Supported Ionic Liquid-Phase adsorbents (SILPs), including the novel inversely structured SILP “Inverse SILPs”, are thoroughly investigated. ZIF-8, ZIF-69 and ZIF-70 were involved as the solid matrix, while ILs, having tricyanomethanide (TCM) as an anion and alkyl-methylimidazolium of different alkyl chain lengths (C₂, C₆, C₈) as a cation, were used as the liquid constituents of the SILPs. The ultimate target of the work was to ratify a few recently reported cases of enhanced CO₂ absorptivity in ILs due to their incorporation in ZIFs and to corroborate phenomena of CO₂/N₂ selectivity improvements in ZIFs, due to the presence of ILs. This ambiguity originates from the vague assumption that the pores of the ZIF are filled with the IL phase, and the free pore volume of a SILP is almost zero. Yet, through the integration of theoretical predictions with N₂ porosimetry analysis of an actual sample, it is suggested that a thin layer of IL covered the exterior surface of a ZIF crystal. This layer could act as an impermeable barrier for N₂, inhibiting the gas molecules from reaching the empty cavities laying underneath the liquid film during porosimetry analysis. This consideration is based on the fact that the solubility of N₂ in the IL is very low, and the diffusivity at 77 K is negligible. In this context, the observed result reflects an averaged adsorptivity of both the IL phase and the empty pores of the ZIF. Therefore, it is incorrect to attribute the adsorption capacity of the SILP solely to the mass of the IL that ‘hypothetically’ nests inside the pore cavities. In fact, the CO₂ adsorption capacity of SILPs is always less than the average adsorptivity of an ideal ZIF/IL mixture, where the two phases do not interact. This reduction occurs because some ZIF pores may become inaccessible, particularly when the IL forms a layer on the pore walls, leaving only a small empty core accessible to CO₂ molecules. Additionally, the IL layer masks the active sites on the ZIF’s pore walls. It should also be noted that the CO₂/N₂ selectivity increases only when the ZIF’s pores are completely filled with the IL phase. This is because ILs have a higher CO₂/N₂ selectivity compared to the bare ZIF. Full article

The corrosion–wear coupling damage failure of 8Cr4Mo4V bearing steel under marine atmospheric conditions significantly limits aeroengine bearing applications. The present work aims to investigate the evolution of the corrosion–wear properties of 8Cr4Mo4V bearing steel at varied corrosion intervals and estimate the corrosion–wear interaction (CWI) effect. Neutral salt spray tests combined with tribological experiments were employed to explore the effect of corrosion on wear and the influence of wear on corrosion, and a quantitative characterization method of corrosion–wear interactions was proposed by establishing the component relationships of material losses in the corrosion–wear process. The results indicate that the corrosion rates initially increase and then decrease, ultimately resulting in a pattern characterized by predominant total corrosion and nested localized corrosion. The corroded surfaces tremendously influence the friction coefficient curves at the third stage, and a synergistic acceleration effect exists in the CWI behavior of 8Cr4Mo4V bearing steel under the action of corrosion and wear. A sample corroded for 6 h displayed the significant facilitative effect of corrosion on wear, exhibiting the highest CWI ratio and a greater total mass loss primarily attributed to corrosion. This study offers a significant reference for the quantitative assessment of the tribo-corrosion properties of bearings in a marine atmospheric environment. Full article

Ant evolutionary success depends mainly on the coordination of colony members, who recognize nestmates based on the cuticular hydrocarbon (CHC) profile of their epicuticle. While several studies have examined variations in this crucial factor for colony identity, few have investigated the anthropic impact on CHC profiles, and none have focused on Lasius paralienus. Here, we surveyed the changes in L. paralienus CHC assemblages across agroecosystems and assessed whether different vineyard management influences these profiles. Soil sampling within ant nests and in close surroundings was performed to measure microhabitat variations. Our results show that the cuticular chemical composition of Lasius paralienus is mainly affected by the differences between areas, with an existing but unclear anthropic influence on them. Normalized soil respiration partially explains these interarea variations. Irrespective of the conventional or organic management, human activities in agroecosystems mostly impacted L. paralienus linear alkanes, a specific class of CHCs known to play a major role against dehydration, but also affected the abundance of compounds that can be pivotal for maintaining the colony identity. Our findings suggest that vineyard practices primarily affect features of the ant cuticle, potentially enhancing microclimate adaptations. Still, the potential effects as disruptive factors need further investigation through the implementation of behavioral bioassays. Full article

Accurate forecasting of high-resolution particulate matter 2.5 (PM_2.5) levels is essential for the development of public health policy. However, datasets used for this purpose often contain missing observations. This study presents a two-stage approach to handle this problem. The first stage is a multivariate spatial time series (MSTS) model, used to generate forecasts for the sampled spatial units and to impute missing observations. The MSTS model utilizes the similarities between the temporal patterns of the time series of the spatial units to impute the missing data across space. The second stage is the high-resolution prediction model, which generates predictions that cover the entire study domain. The second stage faces the big N problem giving rise to complex memory and computational problems. As a solution to the big N problem, we propose a Gaussian Markov random field (GMRF) for innovations with the Matérn covariance matrix obtained from the corresponding Gaussian field (GF) matrix by means of the stochastic partial differential equation (SPDE) method and the finite element method (FEM). For inference, we propose Bayesian statistics and integrated nested Laplace approximation (INLA) in the R-INLA package. The above approach is demonstrated using daily data collected from 13 PM_2.5 monitoring stations in Jakarta Province, Indonesia, for 1 January–31 December 2022. The first stage of the model generates PM_2.5 forecasts for the 13 monitoring stations for the period 1–31 January 2023, imputing missing data by means of the MSTS model. To capture temporal trends in the PM_2.5 concentrations, the model applies a first-order autoregressive process and a seasonal process. The second stage involves creating a high-resolution map for the period 1–31 January 2023, for sampled and non-sampled spatiotemporal units. It uses the MSTS-generated PM_2.5 predictions for the sampled spatiotemporal units and observations of the covariate’s altitude, population density, and rainfall for sampled and non-samples spatiotemporal units. For the spatially correlated random effects, we apply a first-order random walk process. The validation of out-of-sample forecasts indicates a strong model fit with low mean squared error (0.001), mean absolute error (0.037), and mean absolute percentage error (0.041), and a high R² value (0.855). The analysis reveals that altitude and precipitation negatively impact PM_2.5 concentrations, while population density has a positive effect. Specifically, a one-meter increase in altitude is linked to a 7.8% decrease in PM_2.5, while a one-person increase in population density leads to a 7.0% rise in PM_2.5. Additionally, a one-millimeter increase in rainfall corresponds to a 3.9% decrease in PM_2.5. The paper makes a valuable contribution to the field of forecasting high-resolution PM_2.5 levels, which is essential for providing detailed, accurate information for public health policy. The approach presents a new and innovative method for addressing the problem of missing data and high-resolution forecasting. Full article

Prostate cancer is a common cancer among males in the US, but little is known about its risk factors, including trace elements. The primary aim of this study was to examine prostate cancer and its association with arsenic and selenium in toenails. We conducted a small, nested case-control study of men residing in Iowa within the Agricultural Health Study cohort, where we also collected toenail samples to test for arsenic and other trace elements. Toenail samples were sent for neutron activation analysis aimed at long-lived trace elements, including arsenic. Logistic regression was used to estimate odds ratios (ORs) for trace element exposures and prostate cancer. A total of 66 prostate cancer cases and 173 healthy controls returned questionnaires, over 99% of which included toenail samples. An increased risk was seen for the highest levels of arsenic (OR = 3.4 confidence interval (CI) of 1.3–8.6 and OR = 2.2, 95% CI of 0.9–5.6) and the highest level of selenium (2.0, 95% CI of 1.0–4.0). These data also show detectable levels of over 50% for 14 of 22 elements detected in the toenails. The association seen here with arsenic and prostate cancer further supports ecological studies finding an association with community levels of arsenic and prostate cancer incidence and mortality. Full article

The hepatitis D virus (HDV) superinfection of individuals with chronic hepatitis B virus (HBV) infection causes severe liver damage and the poorest long-term prognosis among viral hepatitis. This is attributed to the unique pathogenic mechanisms of HDV characterized by a direct cytopathic effect on hepatocytes and a significant impairment of the host immune response. The HDV genotype largely influences the extent of the pathogenic mechanisms with consequences on disease progression towards cirrhosis, liver decompensation, or hepatocellular carcinoma. In this context, identifying the circulating HDV genotypes in European regions with high prevalence, such as Romania, is crucial for effectively managing the long-term liver health. Here, we report the first comprehensive HDV study in Romania that clinically characterizes 82 patients and performs HDV genotyping by combining the nested-PCR reaction with sequencing analysis in 49 samples with an HDV-RNA load higher than 5000 IU/mL. While all isolates in our study belong to the HDV-1 genotype, the phylogenetic analysis based on sequence data from GenBank reveals the presence of the following potential three groups: (i) Italy and France; (ii) Spain; and (iii) Turkey, Iran, Pakistan, and Germany. This broad clustering highlights the recent surge in migration to and from Western Europe and the Middle East. Equally important, no differences in viral markers, clinical and paraclinical parameters, or treatment options were observed between these identified clusters. Nevertheless, this study considerably advances the understanding of hepatitis D epidemiology and clinical aspects in Romania. Full article

The commensal Escherichia coli in the gut of pigs is a major reservoir of antimicrobial resistance and can result in possible transmission to humans through the food chain. Direct detection of E. coli from fecal samples is challenging and can be used as a bioindicator of antimicrobial resistance. This study aimed to compare the antimicrobial susceptibility profiles in commensal E. coli from antibiotic- and nonantibiotic-using pig farms and developed the direct detection of ESBL genes in pig fecal samples using nested PCR (nPCR) and multiplex PCR (mPCR) techniques. All direct genotypic results were validated with the results of PCR sequencing of isolated E. coli colonies. The ESBL-producing E. coli were found in 98.6% (145 isolates) and 96.6% (144 isolates) of antibiotic-using and nonantibiotic-using farms, respectively, predominantly CTX-M-55. The nPCR decreased the limit of detection (LOD) from sPCR about 100 times, and the lower LODs of 10², 10¹, and 1 CFU/mL were reached after incubating samples in an enrichment medium for 2, 4, and 8 h, respectively. The mPCR, sPCR, and nPCR techniques showed sensitivities of 30.15%, 69.85%, and 91.91%, respectively, compared to PCR sequencing. The stability and recycling of ESBL genes were independent of antibiotic usage in commensal E. coli originating in pig farms. Full article

The impoundment of Aoos springs was created in 1990 to facilitate hydroelectric production, and fish fauna has been enriched through the years due to deliberate or accidental fish stockings, with certain invasive alien fish species arising (i.e., Lepomis gibbosus, Carassius gibelio), some of which are ranked among the most dangerous species for global biodiversity. A three-year monitoring survey was conducting to map the nesting areas of Pumpkinseed, L. gibbosus, to assess the effectiveness of electrofishing as an active method to reduce the spread of the corresponding species and to identify the impact of the L. gibbosus on native species. The largest percentage of nests was found in areas with silty-sand bottoms (53.4%) and low vegetation. The potential nesting area was estimated at 1.97 km² and the area of confirmed nesting was 0.33 km². The species appeared to nest in a small area, compared to the potential nesting area. The results also indicate that a significant percentage of the target species (71.6% of the total number of species) was removed, with an average time per sampling of 1.2 ± 1 h, whereas the impact on the other native species was minimal. These results are important for designing and implementing programs for the eradication or reduction of L. gibbosus in the impoundment of Aoos springs. Full article

Non-human primates (NHPs) host a variety of helminth and protist parasites that are able to cause infection in humans. Gastrointestinal parasites in NHPs living in two zoological gardens of Northern Italy were studied. An total of 96 faecal pools were collected from 26 groups of NHPs. The mini-Flotac method was applied to fecal samples to detect gastrointestinal helminthiases, while the detection of the protists Cryptosporidium spp., Blastocystis sp. and Giardia duodenalis was performed by targeting SSU rRNA through nested PCR and real-time PCR; they were further studied by sequencing the same gene for Blastocystis and βgiardine and triosephosphate isomerase (TPI) genes for Giardia. Twenty-two out of the 96 examined fecal pools (22.9%) were positive for one or more helminth species, including Hymenolepis diminuta, Trichurid, Capillariid and Strongylid eggs. All samples were negative for Cryptosporidium spp., while 16/26 (61.5%) animals were positive for G. duodenalis in the real-time PCR; the sequences obtained assigned them all to sub-assemblage BIV. Blastocystis sp. was detected in 22/26 of the NHPs (84.6%); molecular analyses attributed the isolates to ST 4, allele 92. Analyses of the feces of sympatric rats revealed the presence of the same allele, as well as of Hymenolepis diminuta eggs, raising concern about their role as parasite reservoirs in the facilities. Full article

The detection of genetic alterations in patients with acute leukemias is essential for the targeting of more specific and effective therapies. Therefore, the aim of this study was to compare the sensitivity of Nested-PCR and RT-qPCR techniques in the detection of genetic alterations in patients with acute leukemias. This study included samples from 117 patients treated at the Fortaleza General Hospital. All samples were submitted to analysis using the Nested-PCR and the RT-qPCR techniques. Acute Myeloid Leukemia (AML) patients’ samples were submitted to the analysis of the following alterations: FLT3-ITD, RUNX1::RUNX1T1, CBFB::MYH11 and PML::RARA; meanwhile, BCR::ABL1, TCF3::PBX1, KMT2A::AFF1, ETV6::RUNX1, and STIL::TAL1 fusions were investigated in the Acute Lymphoblastic Leukemia (ALL) patients’ samples. Throughout the study, 77 patients were diagnosed with AML and 40 with ALL. Among the 77 AML patients, FLT3-ITD, RUNX1::RUNX1T1, PML::RARA, and CBFB::MYH11 were detected in 4, 7, 10 and 8 patients, respectively. Among the 40 ALL patients, the presence of 23 patients with BCR::ABL1 translocation and 9 patients with TCF3::PBX1 translocation was observed through the RT-qPCR methodology. Overall, the present study demonstrated that the RT-qPCR technique presented a higher sensitivity when compared to the Nested-PCR technique at the time of diagnosis of the acute leukemia samples studied. Full article

Objective: Knowledge of the role of hospital conditions in SARS-CoV-2 transmission should inform strategies for the prevention of nosocomial spread of this pathogen and of similarly transmitted viruses. This study aimed to identify risk factors for nosocomial acquisition of SARS-CoV-2. Methods: We ran a nested case-control study with incidence density sampling among adult patients hospitalized for >7 days (August–December 2020). Patients testing positive for SARS-CoV-2 after the 7th day of hospitalization were defined as cases and matched with controls (1:4) by date of admission, hospitalization duration until index date, and type of department. Individual and contextual characteristics were gathered, including admission characteristics and exposures during the risk period. Conditional logistic regression was used to estimate the odds ratios (ORs) with respective 95% confidence intervals (CI) separately for probable (diagnosed on day 8–13) and definitive (diagnosed after day 14) nosocomial sets. Results: We identified 65 cases (31 probable; 34 definitive) and 219 controls. No individual characteristic was related to nosocomial acquisition of SARS-CoV-2. Contextual risk factors for nosocomial acquisition were staying in a non-refurbished room (probable nosocomial: OR = 3.6, 1.18–10.87), contact with roommates with newly diagnosed SARS-CoV-2 (probable nosocomial: OR = 9.9, 2.11–46.55; definitive nosocomial: OR = 3.4, 1.09–10.30), and contact with roommates with a first positive test 21–90 days before the beginning of contact (probable nosocomial: OR = 10.7, 1.97–57.7). Conclusions: Hospital conditions and contact with recently infected patients modulated nosocomial SARS-CoV-2 transmission. These results alert us to the importance of the physical context and of agile screening procedures to shorten contact with patients with recent infection. Full article

Enzootic bovine leukosis, a neoplastic disease caused by the bovine leukemia virus (BLV), was the primary cancer affecting cattle in China before 1985. Although its prevalence decreased significantly between 1986 and 2000, enzootic bovine leukosis has been re-emerging since 2000. This re-emergence has been largely overlooked, possibly due to the latent nature of BLV infection or the perceived lack of sufficient evidence. This study investigated the molecular epidemiology of BLV infections in dairy cattle in Henan province, Central China. Blood samples from 668 dairy cattle across nine farms were tested using nested polymerase chain reaction assays targeting the partial envelope (env) gene (gp51 fragment). Twenty-three samples tested positive (animal-level prevalence of 3.4%; 95% confidence interval: 2.2, 5.1). The full-length env gene sequences from these positive samples were obtained and phylogenetically analyzed, along with previously reported sequences from the GenBank database. The sequences from positive samples were clustered into four genotypes (1, 4, 6, and 7). The geographical annotation of the maximum clade credibility trees suggested that the two genotype 1 strains in Henan might have originated from Japan, while the genotype 7 strain is likely to have originated from Moldova. Subsequent Bayesian stochastic search variable selection analysis further indicated a strong geographical association between the Henan strains and Japan, as well as Moldova. The estimated substitution rate for the env gene ranged from 4.39 × 10⁻⁴ to 2.38 × 10⁻³ substitutions per site per year. Additionally, codons 291, 326, 385, and 480 were identified as positively selected sites, potentially associated with membrane fusion, epitope peptide vaccine design, and transmembrane signal transduction. These findings contribute to the broader understanding of BLV epidemiology in Chinese dairy cattle and highlight the need for measures to mitigate further BLV transmission within and between cattle herds in China. Full article

Feline calicivirus (FCV) is a highly contagious virus that causes upper respiratory tract disease, commonly known as cat flu. It is widely distributed worldwide and poses a major threat to feline health. Therefore, it is essential to find an efficient and rapid method for detecting FCV. In this study, the colorimetric reverse transcription loop-mediated isothermal amplification (RT-LAMP) assay, using neutral red as an indicator, was developed and validated to target the ORF2 gene of FCV for the first time. Additionally, the study compared the diagnostic abilities of polymerase chain reaction (PCR), nested PCR, and RT-LAMP assays for detecting FCV in clinical samples. The optimized RT-LAMP amplification was carried out at 56.3 °C. The technique visually detected FCV within 70 min, with a limit of detection of 14.3 × 10¹ copies/µL, and showed no cross-reactivity with other feline pathogens. Out of 54 oropharyngeal swab samples, 17 tested positive for FCV using both nested PCR and RT-LAMP, while only one tested positive using conventional PCR. The positivity rate was higher with nested PCR and RT-LAMP (31.48%) compared to conventional PCR (1.85%). Consequently, these results demonstrated the effectiveness of the colorimetric RT-LAMP assay developed in this study as an alternative for diagnosing FCV in cats. Full article