Intense human-animal interaction and limited capacity for the surveillance of zoonoses as drivers for Hepatitis E virus infections among animals and humans in Lao PDR

Purpose: In Lao People's Democratic Republic (PDR), overlapping habitats of the population and livestock create a propitious environment for zoonoses. Insufficient hygienic measures in slaughterhouses and in rural settings further increase the risk for zoonotic transmission. Limited laboratory capacity as well as lack of background knowledge prevent timely control of disease oubreaks. Here, we assess the occurrence and transmission of Hepatits E virus (HEV), as well as public awareness of zoonoses. Methods & Materials: In 2015 and 2016, samples were collected from ruminants in rural areas (n=211), as well as from slaughterhouse workers (n=129) and slaughter pigs (n=290) in Lao PDR. Using commercial ELISAs, presence of antibodies (IgG, IgM and IgA) against HEV was assessed. Fecal shedding of HEV by animals was investigated using a generic real-time PCR. Detected viruses were characterized by Sanger sequencing if feasible. Using a standardized questionnaire, data on risk factors for zoonotic pathogen transmission and awareness on zoonoses were captured. Much emphasis was placed on collaborating with local actors and on strengthening laboratory capacities. Results: Anti-HEV antibodies were detected in 13% of ruminants in rural settings and in 46% of slaughter pigs. 7% of the ruminants and 2% of the pigs shed HEV that were thus far not characterizable. While anti-HEV antibody seroprevalence was of 33% in people exposed to pigs, only 15% of the non-exposed control group were seropositive (p= 0.001). Awareness of zoonoses among farmers and slaughterhouse workers was low. Wearing protective equipment was associated with a decrease in anti-HEV antibody detection (p=0.024). Limiting the consumption and use of groundwater and cooking of meat further reduced the risk for HEV infection in a domestic context. Conclusion: We could show that people who are exposed to livestock and pigs are at higher risk for contracting HEV than the general population. Although shedding rates were relatively low, animals may represent an infection source that can be controlled by applying personal protective equipment. Building the capacity for the detection and prevention of infectious diseases and increasing awareness about zoonoses in developing countries is a prerequisite for combating infectious disease outbreaks in future

Delirium in older patients undergoing aortic valve replacement: incidence, predictors, and cognitive prognosis.

Transcatheter aortic valve replacement is increasingly performed in frail older patients who were previously ineligible for a standard surgical procedure. The objectives of this study are to determine delirium incidence, predictors, and relationship with cognitive performance at 3-month follow-up in older patients undergoing aortic valve replacement (AVR). Patients (N = 93) aged 70 years and older, undergoing transcatheter (TAVR, N = 66) or surgical (SAVR, N = 27) aortic valve replacement in an academic medical center were enrolled in this prospective cohort study. Delirium was assessed using the Confusion Assessment Method (CAM) on postoperative days 1, 2, 3, and 7. Data on patients' socio-demographics, functional status (including instrumental activities of daily living (IADL), and surgical risk scores (including Society of Thoracic Surgeons (STS) risk score), were collected at baseline. Cognitive status was assessed with the Mini-Mental Status Exam (MMSE) and the Clock Drawing Test (CDT) at baseline and 3 months after AVR. Delirium occurred in 21 (23%) patients, within the first three postoperative days in 95% (20/21) of the cases. Delirium incidence was lower in TAVR (13/66 = 20%) than SAVR (8/27 = 30%) patients, but this difference was not statistically significant (p = .298). Patients with delirium had lower baseline cognitive performance (median MMSE score 27.0 ± 3.0 vs 28.0 ± 3.0, p = .029), lower performance in IADL (7.0 vs 8.0, p = .038), and higher STS risk scores (4.7 ± 2.7 vs 2.9 ± 2.3, p = .020). In multivariate analyses, patients with intermediate (score > 3 to ≤8) and high (score > 8) STS risk scores had 4.3 (95%CI 1.2-15.1, p = .025) and 16.5 (95%CI 2.0-138.2, p = .010), respectively, higher odds of incident delirium compared to patients with low (score ≤ 3) STS risk scores. At 3-month follow-up (N = 77), patients with delirium still had lower MMSE score (27.0 ± 8.0 vs 28.0 ± 2.0, p = .007) but this difference did not remain significant once adjusting for baseline MMSE (β-coefficient 1.11, 95%CI [- 3.03-0.80], p = .248). Delirium occurred in about one in five older patients undergoing AVR, almost essentially within the first three postoperative days. Beside cognitive performance, STS risk score could enhance the identification of high-risk older patients to better target preventative interventions

Livestock diseases threatening smallholder farmers in Lao people's Democratic Republic

Purpose: In Lao People's Democratic Republic, uncontrolled animal trade, lack of animal containment and limited access to veterinary services are a growing-ground for virus spread. Foot-and-Mouth Disease (FMD) and several avian viruses are enzootic and threaten subsistence farmers. We assessed the (sero-)prevalence of several livestock viruses, and evaluated the knowledge, attitude, and practice of smallholder farmers towards FMD. Methods & Materials: In 2018, sera were collected from 394 domestic ruminants and screened using an ELISA that differentiates between infected and vaccinated animals. Questionnaires (n = 101) were statistically explored to identify knowledge gaps and risk factors related to FMD. In addition, oral and cloacal swabs, collected from 619 backyard poultry in 2011, 2014 and 2015, were tested by PCR for Newcastle disease (NDV), Influenza A, Coronavirus (CoV) and Chicken Anemia Virus (CAV). 206 poultry sera were screened by ELISA for the presence of anti-NDV and –Influenza A antibodies. Statistical and phylogenetic analyses revealed the viral infection patterns. Results: Although most farmers had very limited knowledge about FMD, many could correctly enumerate the symptoms and observed outbreaks recently. This was confirmed by our laboratory analysis: overall 37.1% of the animals were seropositive and 72.3% of the farms had at least one seropositive animal. Approx. 90% of the farmers reported that FMD negatively affects livestock trade and health. Moreover, we found high positivity rates of CoV and CAV RNA in cloacal and oral swabs (CoV: 38.3% and 6.2%; CAV: 16.1% and 1.7%). Younger animals were more likely to shed both, CoV and CAV, and similar virus strains co-circulated in chickens and ducks. Despite serological evidence of NDV and influenza A circulation (86.9% and 1.9%), viral RNA was detected in none of the swabs. Conclusion: A large proportion of the Lao population relies on subsistence livestock production which is, as shown here, severely compromised by the circulating viruses. To secure their livelihoods, vaccination programmes should target all susceptible hosts and achieve a high coverage throughout the country. These campaigns should be complemented by community-based sensitization to raise the awareness about prevention strategies, such as quarantine and trade restrictions

<i>In</i> <i>vitro </i>regulation of fibroblast growth factor 23 by 25-hydroxyvitamin D and 1,25-dihydroxyvitamin D synthesized by osteocyte-like MC3T3-E1 cells

Fibroblast growth factor 23 (FGF23) is produced and secreted by osteocytes and is essential for maintaining phosphate homeostasis. One of the main regulators of FGF23, 1,25-dihydroxyvitamin D (1,25(OH)2D3), is primarily synthesized in the kidney from 25-hydroxyvitamin D (25(OH)D) by 1α-hydroxylase (encoded by CYP27B1). Hitherto, it is unclear whether osteocytes can convert 25(OH)D and thereby allow for 1,25(OH)2D3 to induce FGF23 production and secretion locally. Here, we differentiated MC3T3-E1 cells toward osteocyte-like cells expressing and secreting FGF23. Treatment with 10-6 M 25(OH)D resulted in conversion of 25(OH)D to 150 pmol/L 1,25(OH)2D3 and increased FGF23 expression and secretion, but the converted amount of 1,25(OH)2D3 was insufficient to trigger an FGF23 response, so the effect on FGF23 was most likely directly caused by 25(OH)D. Interestingly, combining phosphate with 25(OH)D resulted in a synergistic increase in FGF23 expression and secretion, likely due to activation of additional signaling pathways by phosphate. Blockage of the vitamin D receptor (VDR) only partially abolished the effects of 25(OH)D or 25(OH)D combined with phosphate on Fgf23, while completely inhibiting the upregulation of cytochrome P450 family 24 subfamily A member 1 (Cyp24a1), encoding for 24-hydroxylase. RNA sequencing and in silico analyses showed that this could potentially be mediated by the nuclear receptors Retinoic Acid Receptor β (RARB) and Estrogen Receptor 2 (ESR2). Taken together, we demonstrate that osteocytes are able to convert 25(OH)D to 1,25(OH)2D3, but this is insufficient for FGF23 activation, implicating a direct effect of 25(OH)D in the regulation of FGF23, which occurs at least partially independent from its cognate VDR. Moreover, phosphate and 25(OH)D synergistically increase expression and secretion of FGF23, which warrants investigating consequences in patients receiving a combination of vitamin D analogues and phosphate supplements. These observations help us to further understand the complex relations between phosphate, vitamin D, and FGF23.</p

Organic phosphate but not inorganic phosphate regulates Fgf23 expression through MAPK and TGF-ꞵ signaling

One of the main regulators of phosphate homeostasis is fibroblast growth factor 23 (FGF23), secreted by osteocytes. The effects of organic versus inorganic dietary phosphate on this homeostasis are unclear. This study used MC3T3-E1 FGF23-producing cells to examine the transcriptomic responses to these phosphates. Most importantly, the expression and secretion of FGF23 were only increased in response to organic phosphate. Gene ontology terms related to a response to environmental change were only enriched in cells treated with organic phosphate while cells treated with inorganic phosphate were enriched for terms associated with regulation of cellular phosphate metabolism. Inhibition of MAPK signaling diminished the response of Fgf23 to organic phosphate, suggesting it activates FGF23. TGF-β signaling inhibition increased Fgf23 expression after the addition of organic phosphate, while the negative TGF-β regulator Skil decreased this response. In summary, the observed differential response of FGF23-producing to phosphate types may have consequences for phosphate homeostasis.</p

Organic phosphate but not inorganic phosphate regulates Fgf23 expression through MAPK and TGF-ꞵ signaling

One of the main regulators of phosphate homeostasis is fibroblast growth factor 23 (FGF23), secreted by osteocytes. The effects of organic versus inorganic dietary phosphate on this homeostasis are unclear. This study used MC3T3-E1 FGF23-producing cells to examine the transcriptomic responses to these phosphates. Most importantly, the expression and secretion of FGF23 were only increased in response to organic phosphate. Gene ontology terms related to a response to environmental change were only enriched in cells treated with organic phosphate while cells treated with inorganic phosphate were enriched for terms associated with regulation of cellular phosphate metabolism. Inhibition of MAPK signaling diminished the response of Fgf23 to organic phosphate, suggesting it activates FGF23. TGF-β signaling inhibition increased Fgf23 expression after the addition of organic phosphate, while the negative TGF-β regulator Skil decreased this response. In summary, the observed differential response of FGF23-producing to phosphate types may have consequences for phosphate homeostasis.</p

Conductance and supercurrent discontinuities in atomic size point contacts

Wetensch. publicatieFaculteit der Wiskunde en Natuurwetenschappe

Quantum Conductance in Silver Nanowires: correlation between atomic structure and transport properties

We have analyzed the atomic arrangements and quantum conductance of silver nanowires generated by mechanical elongation. The surface properties of Ag induce unexpected structural properties, as for example, predominance of high aspect ratio rod-like wires. The structural behavior was used to understand the Ag quantum conductance data and the proposed correlation was confirmed by means of theoretical calculations. These results emphasize that the conductance of metal point contacts is determined by the preferred atomic structures and, that atomistic descriptions are essential to interpret the quantum transport behavior of metal nanostructures.Comment: 4 pages, 4 figure