This research critically examines a new chapter in the evolution of the entrepreneurial city; one distinguished by its reliance on Richard Florida’s thesis about the relationship between the creative ...class and economic growth. Since the 2002 publication of his wildly-popular book,
The Rise of the Creative Class, Florida’s ideas were broadly assimilated into the infrastructure of urban entrepreneurialism across the United States. This was especially the case in slow-growth metropolitan areas, where it was hoped that a “creative city” development strategy might reverse decades of relative decline. Using Milwaukee, Wisconsin as a representative case study, this paper scrutinizes the actions of that city’s image-makers, planners, and municipal actors, who together orchestrated a new round of urban promotional activities and planning strategies. What made this new round of growth coalition activities unique was that it highlighted a distinct set of urban motifs presumably commensurate with creative class lifestyles, cultural practices, and consumption habits. Following MacLeod MacLeod, G (2002) From urban entrepreneurialism to a “revanchist city”?: on the spatial injustices of Glasgow’s renaissance.
Antipode
34(3), 602–614, Maliszewski Maliszewski, P (2004) Flexibility and its discontents.
The Baffler
16, 69–79 and Peck Peck, J (2005) Struggling with the creative class.
International Journal of Urban and Regional Research
29(4), 740–770, this work argues that this creative city growth strategy worked primarily to repackage and strengthen the extant downtown-based property-led development paradigm. The marriage of Florida’s ideas with municipal action therefore brought into even sharper relief what was already one of the most economically and racially polarized large cities in the United States.
Porcine epidemic diarrhea virus (PEDV) was identified in the United States (U.S.) swine population for the first time in April 2013 and rapidly spread nationwide. However, no information has been ...published regarding the minimum infectious dose (MID) of PEDV in different pig models. The main objective of this study was to determine the oral minimum infectious dose of PEDV in naïve conventional neonatal piglets and weaned pigs. A U.S. virulent PEDV prototype isolate (USA/IN19338/2013) with known infectious titer was serially ten-fold diluted in virus-negative cell culture medium. Dilutions with theoretical infectious titers from 560 to 0.0056 TCID50/ml together with a medium control were orogastrically inoculated (10ml/pig) into 7 groups of 5-day-old neonatal pigs (n = 4 per group) and 7 groups of 21-day-old weaned pigs (n = 6 per group). In 5-day-old pigs, 10ml of inoculum having titers 560-0.056 TCID50/ml, corresponding to polymerase chain reaction (PCR) cycle threshold (Ct) values 24.2-37.6, resulted in 100% infection in each group; 10ml of inoculum with titer 0.0056 TCID50/ml (Ct>45) caused infection in 25% of the inoculated pigs. In 21-day-old pigs, 10ml of inoculum with titers 560-5.6 TCID50/ml (Ct 24.2-31.4) resulted in 100% infection in each group while 10ml of inoculum with titers 0.56-0.0056 TCID50/ml (Ct values 35.3 ->45) did not establish infection in any pigs under study conditions as determined by clinical signs, PCR, histopathology, immunohistochemistry, and antibody response. These data reveal that PEDV infectious dose is age-dependent with a significantly lower MID for neonatal pigs compared to weaned pigs. This information should be taken into consideration when interpreting clinical relevance of PEDV PCR results and when designing a PEDV bioassay model. The observation of such a low MID in neonates also emphasizes the importance of strict biosecurity and thorough cleaning/disinfection on sow farms.
Effects of PRRSV Infection on the Porcine Thymus Wang, Gang; Yu, Ying; Cai, Xuehui ...
Trends in microbiology (Regular ed.),
March 2020, 2020-Mar, 2020-03-00, 20200301, Letnik:
28, Številka:
3
Journal Article
Recenzirano
Porcine reproductive and respiratory syndrome virus (PRRSV) dramatically affects the thymus and its ability to carry out its normal functions. In particular, infection incapacitates PRRSV-susceptible ...CD14pos antigen-presenting cells (APCs) in the thymus and throughout the body. PRRSV-induced autophagy in thymic epithelial cells modulates the development of T cells, and PRRSV-induced apoptosis in CD4posCD8pos thymocytes modulates cellular immunity against PRRSV and other pathogens. Pigs are less able to resist and/or eliminate secondary infectious agents due the effect of PRRSV on the thymus, and this susceptibility phenomenon is long recognized as a primary characteristic of PRRSV infection.
PRRSV induces thymic atrophy and thymocyte apoptosis, with the virus isolate an important factor in determining the degree of the effect.Virus-susceptible thymic CD14pos APCs induce CD4posCD8pos thymocyte apoptosis and thymic epithelial cell autophagy.Extrathymic consequences of PRRSV infection include a reduction in the production of prothymocytes derived from bone marrow.PRRSV may affect thymus functions by reduction of bone marrow-derived prothymocytes and the production of proinflammatory mediators and glucocorticoids.The impact of PRRSV on thymus functions contributes to anomalous immune responses, that is, suppression of type I interferon, deregulated cytokine expression, and delayed development of neutralizing antibodies.
•PRRSV-susceptible cells include bone marrow-derived mononuclear cells, i.e., imDCs, mDCs, monocytes, macrophages, and myeloid precursor cells. PRRSV induces apoptosis in bone marrow-derived cells as ...a direct consequence of infection and indirectly (bystander effect).•The net result of PRRSV infection is acute bone marrow failure, i.e., hypoplasia characterized by the absence of normal myeloid and erythroid precursors and increased red bone marrow M:E ratios. This explains the leucopenia, anemia, and thrombocytopenia observed in PRRSV-infected pigs.•In addition, PRRSV infection of mononuclear cells impairs normal immune functions, e.g., antigen recognition, processing, and presentation to T and B cells. This renders the host less able to resist and/or eliminate secondary infectious agents and partially explains the synergy between PRRSV and bacterial and viral co-infections.
Red bone marrow is physiologically unique in that it is both the major hematopoietic organ and a primary lymphoid organ. Porcine reproductive and respiratory syndrome virus (PRRSV) affects normal bone marrow functions. The cumulative effect of PRRSV infection is acute bone marrow failure, i.e., hypoplasia characterized by the absence of normal myeloid and erythroid precursors and increased red bone marrow M:E ratios. The measurable clinical consequence of PRRSV infection on normal red bone marrow functions is a reduction in the number of cells emigrating to the peripheral blood resulting in leucopenia, anemia, and thrombocytopenia. These observations may be explained by the fact that bone marrow-derived mononuclear cells, i.e., imDCs, mDCs, monocytes, macrophages, and myeloid precursor cells are susceptible to PRRSV. Apoptosis in bone marrow-derived cells occurs both as a direct consequence of infection and indirectly via a bystander effect. Immunologically, PRRSV-susceptible mononuclear cells are the first line of defense against microbial infection and responsible for antigen recognition, processing, and presentation to T and B cells; a critical step in the initiation and development of an effective adaptive immune. Thus, impairment of normal immune function renders the host less able to resist and/or eliminate secondary infectious agents and partially explains the synergy between PRRSV and bacterial and viral co-infections.
Foot-and-mouth disease virus (FMDV) remains an important pathogen of livestock more than 120 years after it was identified, with annual costs from production losses and vaccination estimated at ...€5.3-€17 billion (US$6.5-US$21 billion) in FMDV-endemic areas. Control and eradication are difficult because FMDV is highly contagious, genetically and antigenically diverse, infectious for a wide variety of species, able to establish subclinical carriers in ruminants, and widely geographically distributed. For early detection, sustained control, or eradication, sensitive and specific FMDV surveillance procedures compatible with high through-put testing platforms are required. At present, surveillance relies on the detection of FMDV-specific antibody or virus, most commonly in individual animal serum, vesicular fluid, or epithelial specimens. However, FMDV or antibody are also detectable in other body secretions and specimens, e.g., buccal and nasal secretions, respiratory exhalations (aerosols), mammary secretions, urine, feces, and environmental samples. These alternative specimens offer non-invasive diagnostic alternatives to individual animal sampling and the potential for more efficient, responsive, and cost-effective surveillance. Herein we review FMDV testing methods for contemporary and alternative diagnostic specimens and their application to FMDV surveillance in livestock (cattle, swine, sheep, and goats).
Since the COVID-19 pandemic, improving indoor air quality (IAQ) has become vital for the public as COVID-19 and other infectious diseases can transmit via inhalable aerosols. Air cleaning devices ...with filtration and targeted pollutant treatment capabilities can help improve IAQ. However, only a few filtration/UV devices have been formally tested for their effectiveness, and little data is publicly available and UV doses comparable. In this research, we upgraded a particulate matter (PM) air filtration prototype by adding UV-C (germicidal) light. We developed realistic UV dose metrics for fast-moving air and selected performance scenarios to quantify the mitigation effect on viable airborne bacteria and PM. The targeted PM included total suspended particulate (TSP) and a coarse-to-fine range sized at PM
, PM
, PM
, and PM
. The PM and viable airborne bacteria concentrations were compared between the inlet and outlet of the prototype at 0.5 and 1.0 m
/s (low and high) air flow modes. The upgraded prototype inactivated nearly 100% of viable airborne bacteria and removed up to 97% of TSP, 91% of PM
, 87% of PM
, 87% of PM
, and 88% of PM
. The performance in the low flow rate mode was generally better than in the high flow rate mode. The combination of filtration and UV-C treatment provided 'double-barrier' assurance for air purification and lowered the risk of spreading infectious micro-organisms.
Mycoplasma hyorhinis (MHR) and Mycoplasma hyosynoviae (MHS) are common opportunistic pathogens in the upper respiratory tract and tonsils of swine. The identification of the specific species involved ...in clinical cases using conventional diagnostic methods is challenging. Therefore, a recombinant chimeric polypeptide based on the seven known variable lipoproteins (A-G) specific of MHR and a cocktail of surface proteins detergent-extracted from MHS cultures were generated and their suitability as antemortem biomarkers for serodiagnosis of MHR- and MHS-infection were evaluated by ELISA. M. hyorhinis and MHS ELISA performance, evaluated using serum samples collected over a 56-day observation period from pigs inoculated with MHR, MHS, M. hyopneumoniae, M. flocculare, or Friis medium, varied by assay, targeted antibody isotype, and cutoffs. The progressions of MHR and MHS clinical diseases were evaluated in relation to the kinetics of the isotype-specific antibody response in serum and bacterial shedding in oral fluids during the observation period. In pigs inoculated with MHR, bacterial DNA was detected in one or more of the 5 pens at all sampling points throughout the study, IgA was first detected at DPI 7, one week before the first clinical signs, with both IgA and IgG detected in all samples collected after DPI 14. The peak of MHS shedding (DPI 8) coincided with the onset of the clinical signs, with both IgA and IgG detected in all serum samples collected ≥ DPI 14. This study demonstrated, under experimental conditions, that both ELISAs were suitable for early detection of specific antibodies against MHR or MHS. The diagnostic performance of the MHR and MHS ELISAs varied depending on the selected cutoff and the antibody isotype evaluated. The high diagnostic and analytical specificity of the ELISAs was particularly remarkable. This study also provides insights into the infection dynamics of MHR-associated disease and MHS-associated arthritis not previously described.
To estimate the annual cost of infections attributable to porcine reproductive and respiratory syndrome (PRRS) virus to US swine producers.
Economic analysis.
Data on the health and productivity of ...PRRS-affected and PRRS-unaffected breeding herds and growing-pig populations were collected from a convenience sample of swine farms in the midwestern United States.
Health and productivity variables of PRRS-affected and PRRS-unaffected swine farms were analyzed to estimate the impact of PRRS on specific farms. National estimates of PRRS incidence were then used to determine the annual economic impact of PRRS on US swine producers.
PRRS affected breeding herds and growing-pig populations as measured by a decrease in reproductive health, an increase in deaths, and reductions in the rate and efficiency of growth. Total annual economic impact of these effects on US swine producers was estimated at dollar 66.75 million in breeding herds and dollar 493.57 million in growing-pig populations.
PRRS imposes a substantial financial burden on US swine producers and causes approximately dollar 560.32 million in losses each year. By comparison, prior to eradication, annual losses attributable to classical swine fever (hog cholera) and pseudorabies were estimated at dollar 364.09 million and dollar 36.27 million, respectively (adjusted on the basis of year 2004 dollars). Current PRRS control strategies are not predictably successful; thus, PRRS-associated losses will continue into the future. Research to improve our understanding of ecologic and epidemiologic characteristics of the PRRS virus and technologic advances (vaccines and diagnostic tests) to prevent clinical effects are warranted.
Antemortem detection of
infection in swine production systems has relied on antibody testing, but the availability of tests based on DNA detection and novel diagnostic specimens, e.g., tracheal swabs ...and oral fluids, has the potential to improve
surveillance. A field study was performed over a 14-week period during which 10 pigs in one pen at the center of a room with 1,250 6-week-old pigs housed in 46 pens were intratracheally inoculated with
Thereafter, one tracheal sample, four serum samples, and one oral fluid sample were collected from every pen at 2-week intervals. Tracheal and oral fluid samples were tested for
DNA and serum samples for
antibody. Test results were modeled using a hierarchical Bayesian model, based on a latent spatial piecewise exponential survival model, to estimate the probability of detection by within-pen prevalence, number of positive pens in the barn, sample allocation, sample size, and sample type over time. Analysis showed that tracheal samples provided the earliest detection, especially at large sample sizes. While serum samples are more commonly collected and are less expensive to test, high probability of detection estimates were only obtained 30 days postexposure at large sample sizes. In all scenarios, probability of detection estimates for oral fluids within 30 days were significantly lower than those for tracheal and serum samples. Ultimately, the choice of specimen type, sample number, and assay will depend on testing objectives and economics, but the estimates provided here will assist in the design of
surveillance and monitoring programs for different situations.
Porcine hemagglutinating encephalomyelitis virus (PHEV) is a Betacoronavirus that causes vomiting and wasting disease and/or encephalomyelitis in suckling pigs. This study characterized PHEV ...infection, pathogenesis, and immune response in caesarean-derived, colostrum-deprived (CDCD) neonatal pigs. Infected animals developed mild respiratory, enteric, and neurological clinical signs between 2 to 13 days post oronasal inoculation (dpi). PHEV did not produce viremia, but virus shedding was detected in nasal secretions (1-10 dpi) and feces (2-7 dpi) by RT-qPCR. Viral RNA was detected in all tissues except liver, but the detection rate and RT-qPCR Ct values decreased over time. The highest concentration of virus was detected in inoculated piglets necropsied at 5 dpi in turbinate and trachea, followed by tonsils, lungs, tracheobronchial lymph nodes, and stomach. The most representative microscopic lesions were gastritis lymphoplasmacytic, moderate, multifocal, with perivasculitis, and neuritis with ganglia degeneration. A moderate inflammatory response, characterized by increased levels of IFN-α in plasma (5 dpi) and infiltration of T lymphocytes and macrophages was also observed. Increased plasma levels of IL-8 were detected at 10 and 15 dpi, coinciding with the progressive resolution of the infection. Moreover, a robust antibody response was detected by 10 dpi. An
air-liquid CDCD-derived porcine respiratory cells culture (ALI-PRECs) system showed virus replication in ALI-PRECs and cytopathic changes and disruption of ciliated columnar epithelia, thereby confirming the tracheal epithelia as a primary site of infection for PHEV.
Among the ∼46 virus species in the Family
(2019), many of which are important pathogens of humans and 6 of which are commonly found in pigs, porcine hemagglutinating encephalomyelitis remains one of the least researched. The present study provided a comprehensive characterization of the PHEV infection process and immune responses using CDCD neonatal pigs. Moreover, we used an
porcine respiratory cells culture (ALI-PRECs) system resembling the epithelial lining of the tracheobronchial region of the porcine respiratory tract to demonstrate that the upper respiratory tract is a primary site of PHEV infection. This study provides a platform for further multidisciplinary studies of coronavirus infections.
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