Late development of pustular, erosive lesions in the muzzle of calves inoculated with Pseudocowpox virus.

We studied the pathogenesis of Pseudocowpox virus (PCPV), a zoonotic parapoxvirus associated with mucocutaneous lesions in cattle. Inoculation of calves with PCPV isolate SD 76-65 intranasally (n = 6) or transdermally in the muzzle (n = 2) resulted in virus replication and shedding up to day 13 post-infection (pi). No local or systemic signs were observed in inoculated calves up to day 20pi, when the clinical monitoring was discontinued. However, from days 28-34 pi, seven (7/8) inoculated calves underwent an asynchronous clinical course characterized by development of a few (one or two) to countless papulo-pustular, erosive-fibrinous and scabby lesions in the muzzle, in some cases extending to the lips and gingiva. In some animals, the lesions coalesced, forming extensive fibrinotic/necrotic and scabby plaques covering almost entirely the muzzle. The clinical course lasted 8-15 days and spontaneously subsided after day 42pi. Infectious virus and/or viral DNA were detected in swabs collected from lesions of 5/8 animals between days 34 and 42pi. Histological examination of fragments collected from the muzzle lesions of two affected calves (day 36pi) revealed marked epidermal hyperplasia and severe orthokeratotic and parakeratotic hyperkeratosis, covered by thick scabs. The epidermis showed multifocal areas of keratinocyte coalescing necrosis and mild multifocal vacuolar degeneration. Sera of inoculated calves at 50pi showed partial virus neutralization at low dilutions, demonstrating seroconversion. The delayed and severe clinical course associated with virus persistence in lesions are novel findings and contribute for the understanding of PCPV pathogenesis.

Bichromatic pumping in mid-infrared microresonator frequency combs with higher-order dispersion.

Integrated microresonator-based mid-infrared frequency combs based on III-V semiconductors exhibit pronounced higher-order group velocity dispersion that can make it difficult to achieve stable output. One way to stabilize multiple solitons and their repetition rate is to pump simultaneously at two nearby comb lines. Two-color (or bichromatic) pumping also promises to boost the relatively low conversion efficiencies of single-soliton combs. We present simulations showing that, for a realistic InGaAs/InP ridge waveguide, the stabilization effect occurs over only a limited range of pump power and detuning parameters. We map out the parameter ranges for various regimes of operation in terms of the pump power and detuning and determine that the regimes converge quickly as the dispersion is truncated to progressively higher orders.

Respiratory signs, fever and lymphopenia in calves inoculated with Brazilian HoBi-like pestiviruses.

Hobi-like viruses (HobiPeV) comprise a novel, recently classified species of bovine pestiviruses, originally identified in commercial fetal bovine serum of Brazilian origin and, subsequently, isolated from diseased animals in several countries. Although frequently isolated from clinical cases, most HobiPeV isolates failed to reproduce overt disease in cattle upon experimental inoculation. Herein, we describe the outcome of experimental infection of four to six months-old seronegative calves with two Brazilian HobiPeV isolates. Calves inoculated intranasally with isolate SV478/07 developed viremia between days 2 and 9 post-inoculation (pi) and shed virus in nasal secretions up to day 11pi. These animals presented hyperthermia (day 7 to 10-11 pi) and lymphopenia from days 4 to 8pi. Clinically, all four calves developed varied degrees of apathy, anorexia, mild to moderate respiratory signs (nasal secretion, hyperemia), ocular discharge and pasty diarrhea in the days following virus inoculation. In contrast, calves inoculated with isolate SV757/15 presented only hyperthermia (days 3 to 10-11 pi) and lymphopenia (days 4-8 pi), without other apparent clinical signs. In these animals, viremia was detected up to day 9 pi and virus shedding in nasal secretions lasted up to day 12-14 pi. Both groups seroconverted to the inoculated viruses, developing virus neutralizing (VN) titers from 320 to 5120 at day 28pi. These results extend previous findings that experimental infections of calves with HobiPeV are predominantly mild, yet they also indicate that field isolates may differ in their ability to cause disease in susceptible animals.

Optimized moth-eye anti-reflective structures for As2S3 chalcogenide optical fibers.

We computationally investigate moth-eye anti-reflective nanostructures imprinted on the endfaces of As2S3 chalcogenide optical fibers. With a goal of maximizing the transmission through the endfaces, we investigate the effect of changing the parameters of the structure, including the height, width, period, shape, and angle-of-incidence. Using these results, we design two different moth-eye structures that can theoretically achieve almost 99.9% average transmisison through an As2S3 surface.

Infrared glass-based negative-curvature anti-resonant fibers fabricated through extrusion.

Negative curvature fibers have been gaining attention as fibers for high power infrared light. Currently, these fibers have been made of silica glass and infrared glasses solely through stack and draw. Infrared glasses' lower softening point presents the opportunity to perform low-temperature processing methods such as direct extrusion of pre-forms. We demonstrate an infrared-glass based negative curvature fiber fabricated through extrusion. The fiber shows record low losses in 9.75 - 10.5 µm range (which overlaps with the CO2 emission bands). We show the fiber's lowest order mode and measure the numerical aperture in the longwave infrared transmission band. The possibility to directly extrude a negative curvature fiber with no penalties in losses is a strong motivation to think beyond the limitations of stack-and-draw to novel shapes for negative curvature fibers.

Fabrication tolerances in As2S3 negative-curvature antiresonant fibers.

We computationally investigate fabrication tolerances in As2S3 negative-curvature antiresonant tube-lattice fibers. Since the dominant loss mechanisms for silica in the mid-infrared (mid-IR) is material absorption, As2S3, which offers a reduced loss over that wavelength range, is a natural candidate for mid-IR antiresonant fibers. However, any fiber fabrication technology, including for soft glasses, will have imperfections. Therefore, it is important to know how imperfect fabrication will affect the results of a fiber design. We study perturbations to the fiber, including a nonconstant tube-wall thickness, a single cladding tube with a different radius, a single cladding tube with a different tube-wall thickness, and "key" sections in the jacket.

Irradiance enhancement and increased laser damage threshold in As2S3 moth-eye antireflective structures.

It has been experimentally observed that moth-eye antireflective microstructures at the end of As2S3 fibers have an increased laser damage threshold relative to thin-film antireflective coatings. In this work, we computationally study the irradiance enhancement in As2S3 moth-eye antireflective microstructures in order to explain the increased damage threshold. We show that the irradiance enhancement occurs mostly on the air side of the interfaces and is minimal in the As2S3 material. We give a physical explanation for this behavior.

Effects of inactivated parapoxvirus ovis on cellular and humoral events of the innate immune response in mice.

The immunostimulating properties of inactivated parapoxvirus ovis (iPPVO) have long been demonstrated in vivo and in vitro, yet the biological and molecular mechanisms involved remain largely unknown. We herein report that intraperitoneal inoculation of iPPVO in mice results in stimulation of several events of the innate immune response. Increased interferon I (IFN-I) activity was demonstrated in sera of mice treated with iPPVO at 6 and 12 h post-inoculation (hpi), and enhanced expression of IFN-γ (15-fold increase) and IL-12 (6-fold) mRNA was detected in the spleen of treated mice at 24 and 48 hpi, respectively. A significant increase in neutrophil activity (p<0.01) was observed at 6 hpi in the blood of iPPVO treated mice. In addition, increased phagocytic activity by peritoneal macrophages of iPPVO-treated mice (p<0.01) was detected in vivo (from 24 to 72 hpi) and in vitro (12 to 96 hpi). Bactericidal activity of sera mice treated with iPPVO against Escherichia coli was also increased (p<0.05) at 24 and 72 hpi. Taken together, these results demonstrate that iPPVO administration leads to a transient stimulation of selected innate immune mechanisms, likely contributing to the immunostimulant effects observed against viral and bacterial infections in vivo.

Calculation of the expected output spectrum for a mid-infrared supercontinuum source based on As 2 S3 chalcogenide photonic crystal fibers.

We computationally investigate supercontinuum generation in an As 2 S3 solid core photonic crystal fiber (PCF) with a hexagonal cladding of air holes. With a goal of obtaining a supercontinuum output spectrum that can predict what might be seen in an experiment, we investigate the spectral and statistical behavior of a mid-infrared supercontinuum source using a large ensemble average of 106 realizations, in which the input pulse duration and energy vary. The output spectrum is sensitive to small changes (0.1%) in these pulse parameters. We show that the spectrum can be divided into three regions with distinct characteristics: a short-wavelength region with high correlation, a middle-wavelength region with minimal correlation, and a long-wavelength region where the behavior is dominated by a few rare large-bandwidth events. We show that statistically significant fluctuations exist in the experimentally expected output spectrum and that we can reproduce an excellent match to that spectrum with a converged shape and bandwidth using 5000 realizations.

Epidemiological analysis over two years of SARS-CoV-2 circulation in southern Brazil: old and novel predictors of COVID-19 outcome.

The overwhelming majority of SARS-CoV-2 epidemiological studies cover a narrow time period, making general knowledge about the COVID-19 pandemic difficult. To assess COVID-19-related host aspects in the overall pandemic, we analyzed COVID-19 cases during the first two years of SARS-CoV-2 circulation in southern Brazil. Herein, 390 patients admitted in 2020-2022 to a Brazilian public referral hospital were allocated into two groups according to the COVID-19 outcome: hospital discharge (n=237) or death (n=153). In the univariate analysis, several variables, including sociodemographic, clinical and laboratory aspects (primary data), were significantly different between the analyzed groups. In multivariate logistic regression, eight of these factors remained associated with the COVID-19 outcome. In particular, we report oxygen supplementation and the need for hemodialysis as predictors of hospital discharge and death from COVID-19, respectively. To the best of our knowledge, none of these findings have been previously reported in the Brazilian or world population. In conclusion, our results contribute to current knowledge by demonstrating that factors described at different times may remain associated with COVID-19 over the pandemic and by identifying novel predictors of COVID-19 outcome.

Virological and clinico-pathological features of orf virus infection in experimentally infected rabbits and mice.

Many aspects of the biology of orf virus (ORFV) infection remain poorly understood and attempts to establish animal models have yielded conflicting and non-reproducible results. We herein describe the characterization of ORFV infection and disease in rabbits and mice. A protocol of intradermal inoculation was employed to inoculate 10(8.5)TCID50/mL of ORFV strain IA-82 in the skin of ears, of the back and labial commissures. All inoculated rabbits presented a clinical course characterized by erythema, macules, papules/vesicles or pustules that eventually dried originating scabs. Local signs started around days 3 and 4 post-inoculation (pi) and lasted 3-10 days. Virus was recovered from lesions between days 2 and 14pi. Histological examination of lesions revealed focal proliferative dermatitis with ballooning degeneration and eosinophilic intracytoplasmic inclusion bodies in keratinocytes, histological hallmarks of contagious ecthyma in sheep. A similar, albeit milder clinical course occurred in 5/10 inoculated mice; virus was recovered from lesions from three animals. Inoculated lambs - used as controls - developed severe lesions of contagious ecthyma. VN tests performed at day 28pi failed to detect neutralizing antibodies in all inoculated animals. In contrast, convalescent rabbit sera were positive by ELISA at dilutions from 100 to 400. These results show that rabbits are susceptible to ORFV infection and thus may be used to study selected aspects of ORFV biology.

Diphenyl diselenide and cidofovir present anti-viral activity against Bovine Alphaherpesvirus 2 in vitro and in a sheep model.

Bovine alphaherpesvirus 2 (BoHV-2) - the agent of bovine herpetic mamillitis (BHM) - is related to Human alphaherpesviruses 1 and 2 (HHV-1, HHV-2) and, as such, has been proposed as a model for vaccine and drug testing. We herein investigated the anti-viral activity in vitro against BoHV-2 of three anti-herpetic drugs: Cidofovir (CDV), Fanciclovir (FAM), Foscarnet (PFA), and diphenyl disselenide (Ph2Se2), a compound that has showed activity against HHV-2. Plaque reduction assays (PRA) revealed a significant reduction in viral plaques (p < 0.05) in cells treated with Ph2Se2 (79.7% reduction) or CDV (62.8%). FAM treatment resulted in a slight decrease in plaque number (22.9%, p < 0.05); PFA showed no activity. The effects of Ph2Se2 and CDV, alone or in combination, were investigated in ewes inoculated with BoHV-2 transdermally and submitted to daily topic treatment. Virus inoculated ewes developed lesions progressing through the stages of hyperemia, large papules or depressed dark areas, followed by scab formation. Treatment with Ph2Se2 resulted in reduction in clinical score from day 10 pi onwards (P < 0.05), shortening of clinical course and reduction in duration of virus shedding (P < 0.05) compared to untreated controls. Combined treatment (Ph2Se2 + CDV) and CDV alone, also led to clinical improvement (P < 0.05), yet less pronounced and delayed. These results are promising towards the use of Ph2Se2, alone or in combination with anti-herpetic drugs, in the treatment of udder and teat lesions produced by BoHV-2 in dairy cows.

Genetic identification of a rabies virus from an insectivorous bat in an urban area of Rio Grande do Sul, Brazil.

In Latin America, hematophagous bats are the main reservoirs of rabies virus (RABV) to livestock, to other mammals and, occasionally, to human. Nonetheless, reports of exposure of human and pets to RABV upon aggression by non-hematophagous bats are increasing, possibly facilitated by the synanthropic habits of these bats. We, herein, report the detection and genetic identification of a RABV recovered from an insectivorous bat found sick in a student housing building at the Federal University of Santa Maria, Southern Brazil. Taxonomic characterization identified the captured bat as a member of the genus Nyctinomops, family Molossidae, the group of insectivorous bats. Brain fragments of the bat were positive for RABV antigens by fluorescent antibody test (FAT) and for sequences of the nucleoprotein (N) gene by RT-PCR. The N amplicon was submitted to nucleotide sequencing and analysis, showing that the consensus sequences (SV 33/19) had high identity with RABV sequences of insectivorous bats deposited in GenBank. At phylogenetic tree, the N gene sequences of SV 33/19 clustered with RABV recovered from Nyctinomops laticaudatus, Molossus molossus, and Tadarida lauticaudata bats, and a part of RABV variant 3, 4, and 6, that correspond to Desmodus rotundus, Tadarida brasiliensis, and Lasiurus cinereus, respectively. Although no direct human or domestic animal exposure has been reported, this case strengthens the need for a continuous rabies vaccination in pets in the surrounding areas, since non-hematophagous bats may serve as source of infection for these animals. These findings also call attention for continuous monitoring of populations of synanthropic bats to avoid/prevent human exposure.

Calculation of the expected bandwidth for a mid-infrared supercontinuum source based on As(2)S(3) chalcogenide photonic crystal fibers.

We computationally investigate supercontinuum generation in an As(2)S(3) solid core photonic crystal fiber (PCF) with a hexagonal cladding of air holes. We study the effect of varying the system (fiber and input pulse) parameters on the output bandwidth. We find that there is significant variation of the measured bandwidth with small changes in the system parameters due to the complex structure of the supercontinuum spectral output. This variation implies that one cannot accurately calculate the experimentally-expected bandwidth from a single numerical simulation. We propose the use of a smoothed and ensemble-averaged bandwidth that is expected to be a better predictor of the bandwidth of the supercontinuum spectra that would be produced in experimental systems. We show that the fluctuations are considerably reduced, allowing us to calculate the bandwidth more accurately. Using this smoothed and ensemble averaged bandwidth, we maximize the output bandwidth with a pump wavelength of 2.8 µm and obtain a supercontinuum spectrum that extends from 2.5 µm to 6.2 µm with an uncertainty of ± 0.5 µm. The optimized bandwidth is consistent with prior work, but with a significantly increased accuracy..

Bovine herpesvirus 5 induces an overproduction of nitric oxide in the brain of rabbits that correlates with virus dissemination and precedes the development of neurological signs.

We herein report an investigation of nitric oxide (NO) levels, a candidate molecule for neuronal toxicity and dysfunction, in the brain of rabbits during experimental neurological infection by bovine herpesvirus 5 (BoHV-5). Spectrophotometry for NO products (NO(2) and NO(3)) revealed that NO levels were significantly increased (F(4, 40) = 3.33; P <.02) in several regions of the brain of rabbits with neurological disease, correlating with moderate to high BoHV-5 titers. Immunohistochemistry of brain regions revealed a group of cells with neuronal and astrocyte morphology expressing the enzyme inducible NO synthase (iNOS) close to virus antigen-positive neurons. In addition, the investigation of nitric oxide levels between 2 and 6 days post infection (d.p.i.) revealed an initial increase in NO levels in the olfactory bulb and cortex (OB/OC) and anterior cortex (AC) at day 3 p.i., correlating with the initial detection of virus. As the infection proceeded, increased NO levels-and infectivity-were progressively being detected in the OB/CO and AC at day 4 p.i. (F(12, 128) = 2.82; P <.003); at day 5 p.i. in several brain regions (P <.003 in the OB/OC); and at day 6 p.i. in all regions (P <.003) but the thalamus. These results show that BoHV-5 replication in the brain of rabbits induces an overproduction of NO. The increase in NO levels in early infection correlated spatially and temporally with virus dissemination within the brain and preceded the development of neurological signs. Thus, the overproduction of NO in the brain of BoHV-5-infected rabbits may be a component of the pathogenesis of BoHV-5-induced neurological disease.

A genetic profile of bovine pestiviruses circulating in Brazil (1998-2018).

The pestiviruses bovine viral diarrhea virus 1 (BVDV-1), 2 (BVDV-2), and HoBi-like (HoBiPeV) are endemic among Brazilian cattle, the world's largest commercial bovine herd. In the last two decades (1998-2018) over 300 bovine pestiviruses have been partially or fully sequenced in Brazil, including viruses from different regions, different epidemiological backgrounds, and associated with diverse clinical presentations. Phylogenetic analysis of these viruses demonstrated a predominance of BVDV-1 (54.4%), with subgenotypes -1a (33.9% of total) and -1b (16.3%) being more frequent and subgenotypes -1d, -1e, and -1i at very low frequencies. The overall BVDV-2 frequency was 25.7% but it varied largely by region, reaching up to 48% in Southern states. BVDV-2b was the predominant subgenotype (84.8% of BVDV-2), followed by BVDV-2a (8.86%). HoBiPeV accounted for 19.9% (61/307) of the genotyped viruses and were detected at high frequency in cattle from Northeastern states. These findings demonstrate a unique mix of pestivirus species and subgenotypes, unlike that seen in Europe or North America. The design of effective diagnostic tools, vaccines, and control programs for limiting bovine pestivirus infections in Brazil must take into consideration this unique mix of viruses. This article provides a critical review of two decades of genetic identification of pestiviruses in Brazil.

Molecular and antigenic characterization of Brazilian bovine herpesvirus type 1 isolates recovered from the brain of cattle with neurological disease.

Bovine herpesviruses type 1 and 5 (BoHV-1 and BoHV-5) are closely related yet differ markedly in their neuropathogenic potential. BoHV-1 isolates have been associated with respiratory and genital disease whereas BoHV-5 has been consistently isolated from neurological infection. We report the characterization of five Brazilian BoHV-1 isolates associated with neurological disease, an unusual finding. All five viruses were isolated from the brain of cattle presenting neurological disease, yet prominent histological encephalitis was not observed in three cases. The isolated viruses were identified as BoHV-1 by a glycoprotein C gene-based PCR able to differentiate BoHV-1 from BoHV-5. The identity of the isolates was confirmed by nucleotide sequencing of the amplicons and by restriction analysis of PCR products from another gC region. Monoclonal antibody binding and cross-neutralization assays with BoHV-1 and BoHV-5 antisera showed a typical BoHV-1 antigenic profile. Lastly, inoculation of rabbits with these five BoHV-1 isolates did not result in neurological disease, contrasting with fatal meningoencephalitis produced by BoHV-5. Thus, the involvement of BoHV-1 in neurological disease of cattle is more frequent than previously reported, indicating the need for fast and precise means of differentiating it from BoHV-5. Likewise, the potential role of BoHV-1 in neurological infection in cattle should be further investigated.

Acute and latent infection by bovine herpesvirus type 5 in experimentally infected goats.

The ability of alphaherpesviruses to infect different ruminant species may have important implications for control/eradication efforts. Serological data indicate that goats may be naturally infected with bovine herpesviruses. To investigate the susceptibility of goats to bovine herpesvirus-5 (BoHV-5), 3-4-month-old kids were inoculated intranasally with each of three Brazilian BoHV-5 isolates (G1, n=8; G2, n=5; G3, n=5). The acute infection was characterized by virus shedding in nasal secretions for up to 14 days (titers up to 10(5.97)TCID(50)/mL), mild respiratory signs and conjunctivitis. All animals seroconverted to BoHV-5, developing virus neutralizing (VN) titers from 4 to 32 to the homologous viruses. At day 60 post inoculation (pi), two animals from each group were euthanized for tissue collection and the remaining goats were submitted to dexamethasone administration (0.4 mg kg(-1) for 5 days). Dexamethasone treatment resulted in virus reactivation in 9 out of 12 animals, as ascertained by virus shedding and/or by increase in VN titers. Virus shedding was detected in 8/12 animals and lasted from 1 to 9 days. Latent viral DNA was detected by PCR in the olfactory bulb and/or trigeminal ganglia of 6/6 goats euthanized at day 60 pi and in 12/12 animals euthanized 40 days post-dexamethasone. These results show that young goats are susceptible to BoHV-5 and may shed virus upon reactivation of latent infection. Thus, it is reasonable to expect that goats raised in close contact with cattle in areas where BoHV-5 is endemic may be infected and therefore should be considered potential reservoirs of the virus.

Susceptibility of mice to bovine herpesvirus type 5 infection in the central nervous system.

Bovine herpesvirus type 5 (BoHV-5) is an important pathogen that causes meningoencephalitis in cattle. Few studies have used the mouse as a model for BoHV-5 infection. Despite the fact that BoHV-5 can infect mice with immune deficiencies, little is known about viral replication, immune response, and the course of infection in the central nervous system (CNS) of wild-type mice. Therefore, the aim of this study was to evaluate the response in the CNS of BALB/c mice acutely infected with BoHV-5 at different days post-inoculation (dpi). BoHV-5, when inoculated intracranially, was able to infect and replicate within the CNS of BALB/c mice. Until 15 dpi, the mice were able to survive without showing prominent neurological signs. The infection was accompanied by a Th1 immune response, with a significant expression of the cytokines IFN-γ and TNF-α and chemokine CCL-2. The expression of these cytokines and chemokines was most significant in the early course of infection (3 and 4 dpi), and it was followed by meningoencephalitis with perivascular cuffing and periventriculitis, composed mainly of macrophages and lymphocytes. After the expression of cytokines and chemokine, the mice were able to curb BoHV-5 acute infection in the brain, since there was a decrease in the number of BoHV-5 DNA copies after 3 dpi and viable viral particles were not detected after 6 dpi. Importantly, BoHV-5 was able to infect the trigeminal ganglia during acute infection, since a large number of BoHV-5 DNA copies were detected on 1 and 2 dpi.

Antigenic diversity of Brazilian isolates of HoBi-like pestiviruses.

Hobi-like viruses comprise an unclassified group of bovine pestiviruses related to bovine viral diarrhea virus 1 (BVDV-1) and 2 (BVDV-2). These viruses were originally identified in fetal bovine serum from Brazilian origin and, subsequently, isolated from diseased animals in several countries. Herein we performed an antigenic characterization of eight Brazilian HoBi-like viruses isolated from persistently infected (PI) animals and from gastroenteric disease (2007-2015). Phylogenetic analysis based on the 5' unstranslated region (UTR) clustered these viruses with other HoBi-like viruses from European and Asiatic origin. Monoclonal antibody (MAb) binding indicated variability in the Hobi-like virus glycoprotein E2 and significant differences from the homologous BVDV-1 and BVDV-2 glycoprotein. Analysis of antigenic relatedness based on virus-neutralizing titers using virus-specific antisera revealed that HoBi-like viruses are antigenically very different from BVDV-1 and, to a lesser extent, from BVDV-2. Cross-neutralizing assays between pairs of HoBi-like viruses and their respective antisera indicated the existence of antigenic variability among these viruses, even for viruses isolated from the same herd in different occasions. Moreover, the identification of a HoBi-like isolate with low antigenic similarity with the other isolates indicates the potential existence of antigenic subgroups among HoBi-like virus isolates. Finally, sera of lambs immunized with commercial BVDV vaccines showed low or undetectable neutralizing activity against HoBi-like isolates. These results indicate significant antigenic differences between BVDV genotypes and Brazilian HoBi-like viruses and the existence of antigenic variability within this atypical group of pestiviruses. These findings extend the knowledge about the antigenic diversity of HoBi-like viruses and reinforce the need for their inclusion in current BVDV vaccines.