Shedding Period Research Articles

Giardiasis of domestic animals and its zoonotic significance: A review

Giardiasis is the most common waterborne parasitic intestinal infection ofboth animals and humans worldwide, and it leads to significant morbidity and mortality in animals, particularly in young aged group like calves in the developing and developed world. It is a zoonotic infectious disease where animals are considered as sources of infection for humans through consumption of water and food contaminated with cysts of Giardia. Giardia species differ significantly in host range, with G. duodenalis having the broadest host range and greatest public health significance. Giardia duodenalis has eight different assemblages A through H. The disease Causes gastro intestinal disturbance, gall bladder colic and jaundice. Malabsorption and maldigestion mainly result from a diffuse shortening of epithelial microvillus. Giardia duodenalis (synonyms intestinalis, lamblia) is a flagellate binucleated protozoan, and it has two morphological forms: cysts and trophozoites. The life cycle of Giardia is direct, and the infective stage of the parasite, the cyst, is encysted when released into the feces and is immediately infectious. Trophozoites are pear-shaped, binucleate, multi-flagellated parasite forms and are the disease causing stage and colonize the upper small intestine, where they adhere to the epithelial surface and proliferate by binary fission. Infected animals, contaminated water and feed are main sources of infection. Age of animals, season of the year, area, housing, feeding, management practices are usually considered as risk factors for the occurrence of giardiasis. The infection can be transmitted by the fecal-oral route, or through contaminated food and water. To survive within the intestine, Giardia undergoes antigenic variation and few virulent factors have been identified to be responsible for the infection. These include ventral adhesive disc proteins and surface lectins, the four pairs of flagella which allow for movement and variant surface proteins. The clearance of Giardia from a host requires both innate and adaptive immunity effector mechanisms. The infection can be diagnosed by examining fecal specimens using different coproscopic techniques, serological tests and by molecular analysis. Restricting animals from surface water during periods of high cyst shedding may reduce watershed contamination. Health education on personal and environmental hygiene would help in reducing the occurrence of the infection. This review work tries to gather information on giardiasis of domestic animals with respect to its epidemiology, host immune responses, pathophysiology, distribution and its public health importance.

Nirmatrelvir/ritonavir for patients with SARS-CoV-2 infection and impaired kidney function during the Omicron surge.

Background: Nirmatrelvir/ritonavir has demonstrated effectiveness in high-risk patients with coronavirus disease 2019 (COVID-19). However, investigations on the efficacy and safety of nirmatrelvir/ritonavir in patients with kidney dysfunction are limited. Methods: Data were collected from the patients admitted to a COVID-19 referral center in Shanghai, China. Patients were at least 18years of age and had a baseline estimated glomerular filtration rate (eGFR) of <60ml/min/1·73m2. The primary endpoint was a composite of all-cause mortality, intensive care unit admission, or cardiovascular events. The secondary endpoint was viral shedding. Results: Among the 195 participants, 73 received nirmatrelvir/ritonavir. A lower risk of the primary endpoint was observed in nirmatrelvir/ritonavir recipients compared with non-recipients [adjusted HR 0.56 (95% CI: 0.32-0.96); p = 0.035]. Nirmatrelvir/ritonavir recipients experienced a shorter duration of viral shedding [adjusted HR 3·70 (95%CI: 2.60-5.28); p < 0.001) and faster viral load clearance versus non-recipients. Among the nirmatrelvir/ritonavir users, earlier initiation of nirmatrelvir/ritonavir within 5days since COVID-19 diagnosis was related with shorter viral shedding time (adjusted HR 7.84 [95% CI: 3.28-18.76]; p < 0.001) compared to late initiation. No patients reported serious adverse events during treatment. Conclusion: Our findings support the early initiation of nirmatrelvir/ritonavir for high-risk patients with impaired kidney function. This could improve patient outcomes and shorten the viral shedding period.

Efficacy of a recombinant turkey herpesvirus (H9) vaccine against H9N2 avian influenza virus in chickens with maternal-derived antibodies.

Although vaccines have been widely used for many years, they have failed to control H9N2 avian influenza virus (AIV) in the field in China. The high level of maternal-derived antibodies (MDAs) against H9N2 virus contributes to the H9N2 influenza vaccine failure in poultry. The study aimed to generate a new vaccine to overcome MDAs interference in H9N2 vaccination in chickens. We used turkey herpesvirus (HVT) as a vaccine vector to express H9 hemagglutinin (HA) proteins. The recombinant HVT expressing H9 HA proteins (rHVT-H9) was successfully generated and characterized in primary chicken embryonic fibroblasts (CEFs). Western blot and indirect immunofluorescence assay (IFA) showed that the rHVT-H9 consistently expressed HA proteins. In addition, the rHVT-H9 had similar growth kinetics to the parent HVT. Preliminary animal experiments showed that compared to the conventional inactivated whole virus (IWV) vaccine, the rHVT-H9 stimulated robust humoral immunity in chickens with passively transferred antibodies (PTAs) that were used to mimic MDAs. Transmission experiments showed that the rHVT-H9 induced both humoral and cellular immunity in chickens with PTAs. Furthermore, we used mathematical models to quantify the vaccine's efficacy in preventing the transmission of H9N2 AIV. The results showed that the rHVT-H9 reduced the virus shedding period and decreased the reproduction ratio (R) value in chickens with PTAs after homologous challenge. However, the vaccination in this trial did not yet bring R < 1. In summary, we generated a new rHVT-H9 vaccine, which stimulated strong humoral and cellular immunity, reducing virus shedding and transmission of H9N2 AIV even in the presence of PTAs in chickens.

Experimental Study of the Particles Influence on the Pyramid Wake within the Turbulent Boundary Layer

Particle imaging velocimetry (PIV) was used to study the near-field variation of a pyramid rough element in clear water and a liquid–solid boundary layer (thickness: 60 mm). Particles with an average diameter of 355 µm and Stokes number of 4.3 were injected into a 1:1000 mass ratio (solid particles: water) liquid–solid two-phase solution. Experiments were conducted to collect instantaneous velocity field information in the streamwise–normal direction and streamwise–spanwise direction at a Reynolds number of 8350. Then, the average velocity field and turbulence intensity of the rough element wake under single-phase and two-phase conditions were compared, and the morphology and periodicity of the shedding structure were analyzed by using proper orthogonal decomposition (POD) combined with the power spectral density function (PSD). Particles were shown to have no significant impact on the recirculation area in the streamwise–spanwise plane but did result in a reduction of the recirculation zone in the streamwise–normal plane and a 0.2h closer location of the streamline's origin to the obstacle. Along with the weakening of the upwash structure, the particle phase diminishes the velocity gradient along the span direction and turbulence intensity. Structural shedding at the top of the pyramid and near the wall occurred simultaneously, and the same shedding period was maintained. Particularly, in the first two POD modes, the energy of the shedding structure near the wall was higher than that at the obstacle tip, with a maximum energy differential of approximately 6%. The Strouhal number of the shedding structure decreased by particles from 0.217 to 0.209. The concentration distribution and degree of dispersion in the particle-laden flow illustrate different results, with lower statistics in the wake flow field.

Reduction of oocyte shedding and cecal inflammation by 5-aminolevulinic acid daily supplementation in laying hens infected with Eimeria tenella.

The present study aimed to evaluate the effects of 5-aminolevulinic acid (5-ALA) on Eimeria tenella infection in laying hens. Oocyst shedding and histopathology were evaluated. A reduced oocyst shedding was observed 5 and 7 days post-infection (dpi) in the 5-ALA-administered group, but the total number of oocysts during the first infection period was not different between control and 5-ALA-treated groups. After E.tenella attack infection, the period of oocyst shedding in the 5-ALA-administered group lasted less long than that in controls. During the attack infection period, the total number of fecal oocysts in the 5-ALA-treated group was significantly lower than that in the control group. However, the parasite burden score in hens receiving 5-ALA was higher than that in controls after E.tenella attack infection. The lesion scores at 5 and 30 dpi in the control group were significantly lower than those in the 5-ALA-administered group. Therefore, 5-ALA administration might be beneficial against E.tenella infection in laying hens.

Energy Efficiency in Periods of Load Shedding and Detrimental Effects of Energy Dependence in the City of Maroua, Cameroon

Energy Efficiency in Periods of Load Shedding and Detrimental Effects of Energy Dependence in the City of Maroua, Cameroon

Comparison of secondary attack rate and viable virus shedding between patients with SARS-CoV-2 Delta and Omicron variants: A prospective cohort study.

There are limited data comparing the transmission rates and kinetics of viable virus shedding of the Omicron variant to those of the Delta variant. We compared these rates in hospitalized patients infected with Delta and Omicron variants.We prospectively enrolled adult patients with COVID-19 admitted to a tertiary care hospital in South Korea between September 2021 and May 2022. Secondary attack rates were calculated by epidemiologic investigation, and daily saliva samples were collected to evaluate viral shedding kinetics. Genomic and subgenomic SARS-CoV-2 RNA was measured by PCR, and virus culture was performed from daily saliva samples.A total of 88 patients with COVID-19 who agreed to daily sampling and were interviewed, were included. Of the 88 patients, 48 (59%) were infected with Delta, and 34 (41%) with Omicron; a further 5patients gave undetectable or inconclusive RNA PCR results and 1was suspected of being coinfected with both variants. Omicron group had a higher secondary attack rate (31% [38/124]vs.7% [34/456], p < 0.001). Survival analysis revealed that shorter viable virus shedding period was observed in Omicron variant compared with Delta variant (median 4, IQR [1-7], vs. 8.5 days, IQR [5-12 days], p < 0.001). Multivariable analysis revealed that moderate-to-critical disease severity (HR: 1.96), and immunocompromised status (HR: 2.17) were independent predictors of prolonged viral shedding, whereas completion of initial vaccine series or first booster-vaccinated status (HR: 0.49), and Omicron infection (HR: 0.44) were independently associated with shorter viable virus shedding.Patients with Omicron infections had higher transmission rates but shorter periods of transmissible virus shedding than those with Delta infections.

Numerical Investigation of Vortex Shedding from a 5:1 Rectangular Cylinder at Different Angles of Attack

Although flow around a 5:1 rectangular cylinder at small angles of attack (AoA) has been extensively studied, when the AoA becomes larger, the research is rare. Therefore, this study performs Unsteady Reynolds-Averaged Navier-Stokes simulations (URANS) using the k-ω SST turbulence model for unsteady flow around a two-dimensional 5:1 rectangular cylinder at different AoAs up to 45°. A strong dependence of the flow characteristics on AoA is observed through the analysis of the time-averaged lift coefficient, drag coefficient, and Strouhal number. The peak of lift and drag coefficient is observed to be correlated, respectively, to the leading- and trailing-edge vortex based on the analysis of the flow. The x′-directional length of the main recirculation bubble on the top side and the distance from the bubble center to the leading edge of the cylinder both reach the maximum when α = 15°. In addition, the standard deviation σx′ of the time-averaged velocity U¯x′ along the cylinder shows a trend of increasing at first and then decreasing, and that σy′ also shows the same trend at α = 20°~45°; it fluctuates within a range of 0.05~0.2 at α = 0°~20°. Finally, two principal modes of vortex shedding are observed with α = 15° being their turning point, (i) “1 + 1” mode: in one vortex shedding period, two major vortices shed off from the top and bottom sides of the cylinder at α ≤ 15°; (ii) “2 + 2” mode, four vortices shed off from the top and bottom sides of the cylinder at α &gt; 15° in one vortex shedding period.

Strouhal number and vortices in far wake of cylinder

The wake past a smooth cylinder perpendicular to the flow is studied 15D (cylinder diameters) downstream by using particle image velocimetry (PIV). Spatial shedding period is used to estimate the spatial Strouhal number (Sh) and to compare with time-resolved hot-wire anemometer (HWA). The vortices are detected within the spatial fluctuation field. The statistical vortex properties do not change within the explored range of Reynolds numbers (from 5 000 to 60 000), similarly the spectra and Sh.

Base Temperature Comparisons for Leafing Date, Pistillate Flower Receptivity, and Pollen Shedding in Persian Walnut

Leafing dates and the male and female bloom periods in Persian walnut (Juglans regia L.) vary with cultivars and years. Changes in phenological phases and the process of passing through the phenological stages could be explained by the growing degree days (GDD) if the minimum base temperature (Tb) were determined. In this study, the long-term phenological data of some walnut cultivars derived and/or grown in Hungary and Iran were used to determine the Tb values for leafing date (LD), pistillate flower receptivity start (PRS), pistillate flower receptivity end (PRE), and start and end of the pollen shedding period (PSS and PSE, respectively). The GDD were calculated (with 0.1 °C precision) for the LD and PSS with respect to the earliest cultivar as well as for PRS compared to LD and PRE. Furthermore, the GDD were reckoned for PSE based on PRS and PSS of the same cultivar in each year. The analysis of the data revealed that for the LD, PRS, and PRE, the Tb5.5 with the highest correlation was shown to be the most appropriate. For the PSS and PSE, the best correlation was observed at Tb0 in both countries. The strongest coefficients were observed (0.72 for Iranian and 0.8 for Hungarian conditions) between GDD with Tb of 5.5 °C for PRS and LD. The less correlation was observed between LD and PSS (0.5 for Iranian and 0.57 for Hungarian conditions). The correlation coefficients between GDD and leafing date were the same (0.52) in both countries. Cultivars involved in the trial required more GDD in Iran than in Hungary.

NUTRIENT DYNAMICS IN SOIL ASSOCIATED WITH LEAF LITTER OF Shorea robusta Gaertn. f. IN MADHUPUR SAL FOREST OF BANGLADESH

Litter plays an important role in nutrient cycling in forest ecosystem. Nutrients are released from litter through leaching, and decomposition process and readily available nutrients are obtained through leaching process. Shorea robusta forest is a tropical deciduous forest and shed their leaves during the dry season. In the vicinity, poor people usually collect this litter from the forest to meet household demand for fuel. Thus, a considerable amount of nutrients is lost from this system.However, some nutrients from those leaves is possible to harvest through leaching technique before use as fuel. Therefore, to quantify this nutrient Leaf litter production and leaf litter standing crop were estimated in the Modhupur Sal forest. In addition, mass loss and nutrients (nitrogen, potassium and phosphorus) release through leaching were observed over 192 hours through leaching process in the laboratory. Mean leaf litter production was found 12.94 ± 0.65 g/m2/day during the litter shedding period was estimated to and the mean leaf litter standing crop was found 89.20 ± 9.77g/m2. About 10% of initial mass was lost after 48 hours of leaching process. Moreover, initial concentration of nitrogen and phosphorus was sharply decreased to 65 µg/g and 42 µg/g respectively after 24 hours and initial concentration (38 µg/g) of potassium was sharply decreased to 5 µg/g after 12 hours. About 25%, 45% and 92% of initial N, P and K content, respectively can be extracted through leaching process.

Enhanced inflammation and suppressed adaptive immunity in COVID-19 with prolonged RNA shedding

Little is known regarding why a subset of COVID-19 patients exhibited prolonged positivity of SARS-CoV-2 infection. Here, we found that patients with long viral RNA course (LC) exhibited prolonged high-level IgG antibodies and higher regulatory T (Treg) cell counts compared to those with short viral RNA course (SC) in terms of viral load. Longitudinal proteomics and metabolomics analyses of the patient sera uncovered that prolonged viral RNA shedding was associated with inhibition of the liver X receptor/retinoid X receptor (LXR/RXR) pathway, substantial suppression of diverse metabolites, activation of the complement system, suppressed cell migration, and enhanced viral replication. Furthermore, a ten-molecule learning model was established which could potentially predict viral RNA shedding period. In summary, this study uncovered enhanced inflammation and suppressed adaptive immunity in COVID-19 patients with prolonged viral RNA shedding, and proposed a multi-omic classifier for viral RNA shedding prediction.

Growth and shedding of harbor seal (Phoca vitulina) whiskers

Accurate and precise estimates of the timing of whisker growth and shedding are necessary to interpret biochemical information stored in whiskers. This fine-scale examination of harbor seal ( Phoca vitulina Linnaeus, 1758) whisker growth and shedding identified an asymptotic growth pattern with initial rapid growth that decays over time that can be defined with the von Bertalanffy curve. Initial growth rates were similar among whiskers, but estimated growth coefficients ( K) and asymptotic lengths ( L∞) differed by follicle positions suggesting that differences in total whisker lengths result from dissimilarly shaped growth curves. In other words, longer whisker length is attained by delaying the growth rate decay. There was substantial intra- and interseal variation in shedding dates; whisker shedding began at the caudal margin of the whisker bed and progressed toward the nose. Shedding of marked whiskers from the three study seals took from 78 to 133 days; however, selecting whiskers only from the most caudal follicle of the bottom three rows constrained the period of whisker shedding to 7–43 days. These differences in growth and shedding of harbor seal whiskers emphasize the importance of considering follicle position to select whiskers that are the most similar for analyses of information stored in whiskers.

Detection of SARS-CoV-2 clade B.1.2 in three snow leopards.

Severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) is one of seven coronaviruses known to infect humans. Different from other concerned coronavirus and influenza viruses, SARS‐CoV‐2 has a higher basic reproduction number and thus transmits more efficiently among hosts. Testing animals for SARS‐CoV‐2 may help decipher virus reservoirs, transmission and pathogenesis. Here, we report the first detection of SARS‐CoV‐2 in three snow leopards (Panthera uncia) in a zoo in Kentucky in 2020, the first year of the pandemic. Sequence analysis revealed that snow leopard SARS‐CoV‐2 strains were non‐variant B.1.2 lineage and closely correlated with human strains. One snow leopard shed SARS‐CoV‐2 in faeces up to 4 weeks. Based on clinical signs and viral shedding periods and levels in the three snow leopards, animal‐to‐animal transmission events could not be excluded. Further testing of SARS‐CoV‐2 in animals is needed.

Rabies in an imported dog, Ontario, 2021.

In July 2021, a dog was imported into Canada from Iran and subsequently developed clinical signs of rabies within 11 days of arrival. Following laboratory confirmation of the diagnosis of rabies, local, provincial and federal inter-agency collaboration was required to complete contact tracing to identify all persons and domestic animals that may have been exposed to the rabid dog during the potential virus shedding period. This case highlights the risks of importing animals from known canine rabies-endemic areas, identifies gaps in current dog importation policies that pose potential risk to human and animal health and prompts ongoing vigilance for this deadly disease among human and animal health partners, as well as members of the public who adopt imported dogs.

Contrasting temperature responses in seasonal timing of cercariae shedding by Rhipidocotyle trematodes.

Global warming is likely to lengthen the seasonal duration of larval release by parasites. We exposed freshwater mussel hosts, Anodonta anatina, from 2 high-latitude populations to high, intermediate and low temperatures throughout the annual cercarial shedding period of the sympatric trematodes Rhipidocotyle fennica and R. campanula, sharing the same transmission pathway. At the individual host level, under warmer conditions, the timing of the cercarial release in both parasite species shifted towards seasonally earlier period while its duration did not change. At the host population level, evidence for the lengthening of larvae shedding period with warming was found for R. fennica. R. campanula started the cercarial release seasonally clearly earlier, and at a lower temperature, than R. fennica. Furthermore, the proportion of mussels shedding cercariae increased, while day-degrees required to start the cercariae shedding decreased in high-temperature treatment in R. fennica. In R. campanula these effects were not found, suggesting that warming can benefit more R. fennica. These results do not completely support the view that climate warming would invariably increase the seasonal duration of larval shedding by parasites, but emphasizes species-specific differences in temperature-dependence and in seasonality of cercarial release.

Controlling a human parainfluenza virus-3 outbreak in a haematology ward in a tertiary hospital: the importance of screening strategy and molecular diagnostics in relation to clinical symptoms

The human parainfluenza virus 3 (HPIV-3) outbreak at the haemato-oncology ward of the Maastricht University Medical Centre in the summer of 2016. To describe an effective strategy to control the largest reported HPIV-3 outbreak at an adult haematology-oncology ward in the Netherlands by implementing infection control measures and molecular epidemiology investigation. Clinical, patient and diagnostic data were both pro- and retrospectively collected. HPIV-3 real-time polymerase chain reaction (HPIV-3 RT-PCR) was validated using oropharyngeal rinse samples. Screening of all new and admitted patients was implemented to identify asymptomatic infection or prolonged shedding of HPIV-3 allowing cohort isolation. The HPIV-3 outbreak occurred between 9 July and 28 September 2016 and affected 53 patients. HPIV-3 RT-PCR on oropharyngeal rinse samples demonstrated an up to 10-fold higher sensitivity compared with pharyngeal swabs. Monitoring showed that at first positive PCR, 20 patients (38%) were asymptomatic (of which 11 remained asymptomatic) and the average duration of shedding was 14 days (range 1-58). Asymptomatic patients had lower viral load, shorter period of viral shedding (≤14 days) and were mostly immune-competent oncology patients. The outbreak was under control five weeks after implementation of screening of asymptomatic patients. Implementation of a sensitive screening method identified both symptomatic and asymptomatic patients which had lower viral loads and allowed early cohort isolation. This is especially important in a ward that combines patients with varying immune status, because both immunocompromised and immune-competent patients are likely to spread the HPIV-3 virus, either through prolonged shedding or through asymptomatic course of disease.

Clinical significance and intestinal microbiota composition in immunocompromised children with norovirus gastroenteritis.

BackgroundNorovirus (NoV) infection is common in pediatric patients with immunodeficiency and is more likely to cause severe disease. Objective Our study aims to figure out the clinical differences and distribution of intestinal microbiota in immunocompromised children with NoV gastroenteritis.MethodsPediatric patients admitted to Shang-Ho Hospital with diagnosis of acute gastroenteritis including different immune status were enrolled and their medical records were reviewed. NoV gastroenteritis was validated using RT-PCR molecular methods. Viral shedding period was determined by real-time RT-PCR assays. Intestinal microbiota enrichment analysis was carried out by next generation sequencing after fecal DNA extraction and subsequent Linear Discriminant Analysis (LDA) Effect Size (LEfSe) method.ResultsSignificantly higher frequency of diarrhea [mean, (IQR), 3.8 (3–5) /day] and longer viral shedding time [mean, IQR, 8.5 (5–13) days] was found in immunocompromised NoV infections than in immunocompetent patients without NoV infections (p = 0.013*) and immunocompetent patients with NoV infections (p = 0.030**). The fever prevalence was significantly lower in immunocompromised NoV infections than in different immune or infection status. Intestinal microbiota metagenomics analysis showed no significant community richness difference while the LEfSe analysis showed a significant difference in commensal richness at the phylum level, the family level, and the genus level in patients under different immune status.ConclusionWe evaluated the clinical significances and microbiota composition in immunocompromised children with norovirus gastroenteritis. This will further facilitate studies of the interaction between the intestinal microbiota in such patients with precise determination of their bacterial infection control and probiotic supplements strategy.

Automated load shedding period control system for distribution utility

The authors have described a low-cost wi-fi allotted load shedding system that can be used in both high and low-power applications. The proposed technique employs PLCC to perform partial load shedding or full load shedding based on input power in power transformer locations where a SCADA system cannot be employed. In case of over current drawn, the cutting edge sensor prevents the transformer from damage. This paper presents a design to compute and control the voltage and provide a full or partial load shedding solutions to domestic and industrial consumers.

Duration of infectious viral shedding in patients with mild to moderate COVID-19 treated with REGN-CoV2

IntroductionNew treatment methods, such as REGN-CoV2, have been approved for patients with coronavirus disease (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). However, the effect of the drug on the duration of infectious viral shedding and viral mutations is unknown. In this study, we investigated the clinical efficacy of REGN-CoV2 treatment in patients with mild to moderate disease and compared its antiviral effects against different strains of SARS-CoV-2. MethodsViral culture and PCR testing were performed on the pharyngeal swabs collected from 28 patients with COVID-19 who were admitted and treated at Hiroshima University Hospital during the study period. Of these, 23 patients were treated with REGN-CoV2. The patients were classified into the REGN-CoV2(+) and REGN-CoV2(−) groups, and the clinical course was compared between the groups. The 50% inhibitory concentrations (IC50) of REGN-CoV2 against the isolated virus strains were determined. ResultsAfter treatment with REGN-CoV2, the virus culture positivity rate was greatly reduced. The time to negative viral culture was significantly shorter in the REGN-CoV2(+) group than in the REGN-CoV2(−) group. In vitro evaluation of REGN-CoV2 against isolated virus strains also showed efficacy. ConclusionsREGN-CoV2 treatment was effective in patients with mild COVID-19 and could shorten the period of infectious viral shedding. This may be an important factor in preventing the spread of infection. It may be possible to revise the isolation period for patients with mild disease treated with REGN-CoV2.