Abstract
Antenna-pattern measurements obtained from a double-metal supra-terahertz-frequency (supra-THz) quantum cascade laser (QCL) are presented. The QCL is mounted within a mechanically ...micro-machined waveguide cavity containing dual diagonal feedhorns. Operating in continuous-wave mode at 3.5 THz, and at an ambient temperature of ~60 K, QCL emission has been directed via the feedhorns to a supra-THz detector mounted on a multi-axis linear scanner. Comparison of simulated and measured far-field antenna patterns shows an excellent degree of correlation between beamwidth (full-width-half-maximum) and sidelobe content and a very substantial improvement when compared with unmounted devices. Additionally, a single output has been used to successfully illuminate and demonstrate an optical breadboard arrangement associated with a future supra-THz Earth observation space-borne payload. Our novel device has therefore provided a valuable demonstration of the effectiveness of supra-THz diagonal feedhorns and QCL devices for future space-borne ultra-high-frequency Earth-observing heterodyne radiometers.
Summary
Since 1998, southern Europe has experienced multiple incursions of different serotypes and topotypes of Bluetongue virus, a vector‐borne transmitted virus, the causative agent of Bluetongue ...(BT), a major disease of ruminants. Some of these incursions originated from northern Africa, likely because of wind‐blown dissemination of infected midges. In this report, we describe the detection and whole genome characterization of a novel BTV‐3 strain identified in a symptomatic sheep in Tunisia. Sequences were immediately deposited with the GenBank Database under Accession Nos KY432369‐KY432378. Alert and preparedness are requested to face the next vector seasons in northern Africa and the potential incursion of this novel strain in southern Europe.
West Nile virus (WNV) circulation dynamics in the context of the urban environment is not yet elucidated. In this perspective, three groups of eight rock pigeons (Columbia livia) were inoculated with ...three WNV lineage 1 strains isolated in Italy between 2009 and 2012. The pigeons did not develop any clinical signs consistent with WNV acute infection. All animals seroconverted and shed virus up to 15 days post-infection by the oral or cloacal routes. In all infected groups viraemia lasted for 4 days post-infection. No WNV-specific gross or histological lesions were found in infected birds compared to control birds and immunohistochemistry remained constantly negative from all tissues. The reservoir competence index was also assessed and it ranged between 0·11 and 0·14. This study demonstrates that pigeons are competent reservoir hosts for Italian WNV lineage 1 circulating strains thus potentially posing a risk to the public health system.
Four groups of BTV free Frisian and cross bred calves were used to determine the length of viraemia following infection with different doses of BTV-8 Italian isolate. The first group of five animals ...was infected with 10 TCID
50 of BTV-8, the second group of four animals with 10
3 TCID
50 and the third group, which also included four animals, was infected with 10
6 TCID
50. A placebo containing uninfected tissue culture medium was given to the four animals of the fourth group. The viraemia was evaluated by real time RT-PCR and virus isolation. In all infected groups, virus isolation was able to detect infectious virus up to 39
days post infection (dpi) while RT-PCR was positive up to 151–157
dpi. Infectious dose did influence neither the length nor the pattern of BTV-8 viraemia and confirmed that real time RT-PCR remains positive although no circulating virus is detectable in the peripheral circulation.
This study reports the monitoring of several emerging viral pathogens in Mauritania, which was carried out by the analysis of bovine and camel samples taken at the slaughterhouse of Nouakchott. Blood ...and serum were collected by random sampling from 159 camels and 118 cattle in March 2013 at the large animals abattoir in Nouakchott. Serological tests for Rift Valley Fever (RVF), Peste des Petits Ruminants (PPR), West Nile disease (WND), epizootic haemorrhagic disease (EHD) and African horse sickness (AHS) were carried out using commercial ELISA kits. The samples, which resulted positives for PPR, WND and AHS, were tested with the confirmatory virus neutralization test (VNT). According to ELISA results, serological prevalence of RVF was 45% (95% CI 52.3–37.7) in camels and 16% (95% CI 22.6–9.4) in cattle. The difference between the observed prevalences in camels and in cattle was significant (
p
value ≤ 0.01). PPR was absent in camels and had 12% prevalence (95% CI, 17.86–6.14) in cattle. Furthermore, camels showed 92% (95% CI, 96.1–87.9) prevalence of WNV, 73% (95% CI, 82.3–63.64) of EHD and 3% (95% CI, 5.6–0.4) of AHS. This data are of relevance since provided useful feedbacks on the circulation of the pathogens in field. Moreover, this survey provided new information on the susceptibility of camels to several emerging pathogens and on the possible use of this species as sentinel animal.
Human Norovirus has been reported as the major non-bacterial cause of human gastroenteritis due to the consumption of contaminated bivalve mollusks. The European legislation established ...microbiological criteria only for bacteria (Salmonella spp. and Escherichia coli), while no viruses have still been considered. In this study, samples of Chamelea gallina were harvested along the Central Adriatic coasts (Italy) and artificially contaminated with Murine norovirus-1 (MNV-1) up to a final concentration of 103 TCID.sub.50/ml in water. They were subject to a depuration process in a closed-circuit system using both ozone and ultraviolet light. Four experimental trials (100 specimens/trial) were performed and, at the end of depuration, the digestive glands of mollusks were examined by means of two methods--namely, RT-PCR and tissue culture. The results of RT-PCR ranged from 10.sup.3.17 to 10.sup.4.60 TCID.sub.50/ml, and the constant presence of MNV-1 was confirmed by the tissue culture as well. In conclusion, no significant viral reduction was obtained, but the contaminated bivalve mollusks remained infectious until the end of the depuration treatment. The proper cooking of live bivalve mollusks could be considered the most important preventive measure against this sanitary risk. Keywords: Norovirus, clams, depuration, tissue culture, RT-PCR
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
West Nile virus (WNV) strains belonging to lineage 2 were detected and isolated from the tissues of a goshawk and two carrion crows in Sardinia in August 2012. According to NS3 sequence analysis, the ...Sardinian isolates shared a high level of similarity with those of Italian lineage 2 strains which circulated in 2011 and with the homologous sequence of the 2004 Hungarian isolate. Following the human fatality reported in 2011 in Olbia, this study is the first to report the spread and enzootic circulation of WNV lineage 2 in Sardinia.
Re-Emergence of West Nile Virus in Italy Monaco, F; Lelli, R; Teodori, L ...
Zoonoses and public health,
December 2010, Letnik:
57, Številka:
7-8
Journal Article
Recenzirano
In August 2008, West Nile disease re-emerged in Italy. The infection is affecting the North Eastern regions and, as of November 2008, has caused 33 clinical cases and five fatalities in horses. Until ...now, no deaths have been reported in birds. Mosquitoes, blood, serum and tissue samples, from horses and birds, within and around the outbreak area, have been collected and tested by various methods both serologically and virologically. West Nile virus strains have been isolated from blood samples of one horse and one donkey and from pools of brain, kidneys, heart and spleen of a pigeon and three magpies. When compared to the strain isolated during the 1998 Tuscany outbreak, the 255 bp sequence of the genome region coding for the envelope (E) protein of the isolated WNV strains, exhibited a 98.8% and 100% similarity at nucleotide and amino-acid level respectively.
After 10 years, West Nile virus (WNV) re-emerged in Italy in August 2008. As on 31 December 2008, the infection affected eight Provinces in three Regions (Emilia Romagna, Veneto, Lombardy), where a ...total of 794 cases of WNV infection in 251 equine stables were detected on the basis of the clinical signs and as a result of a serological screening in horses living in the area. Only 4.0% (32/794) of the serologically positive animals showed clinical signs, and the 32 clinical cases were reported in 18 different farms. The observed case-fatality rate was 15.6% (5/32). The confirmed clinical cases were detected from end August to mid October. Significant levels of positivity by RT-PCR were also observed in magpies (Pica pica) (9.1%, 95% confidence levels: 6.1-13.4%), carrion crows (Corvus corone) (7.4%, 95% confidence levels: 3.6-14.4%) and rock pigeons (Columba livia) (12.9%, 95% confidence levels: 7.6-21.2%).
To assess whether pupil dilation influences retinal nerve fibre layer (RNFL) thickness measurements provided by spectral-domain optical coherence tomography (SD-OCT) in healthy individuals.
In this ...observational case series, carried out in a private clinical practice, 32 eyes of 32 participants were investigated. Using Cirrus HD-OCT (Carl Zeiss Meditec, Dublin, CA, USA) three individual 200 × 200 cube optic disc scans were obtained before and after pupil dilation. The RNFL thickness was the outcome measure. Coefficient of variation (COV) and test-retest variability were calculated.
Pupil size did not influence RNFL thickness measurements: mean values did not change in any sector (except the 9 o'clock hour) after dilation. Excellent repeatability was achieved both before and after mydriasis. In the former condition, COV ranged between 1.37% (for average RNFL) and 4.46% (for clock hour 2 RNFL) and test-retest variability between 2.17 (for temporal quadrant RNFL) and 9.18 microm (for clock hour 6 RNFL). In the latter condition, COV ranged between 1.36% (for average RNFL) and 4.48% (for clock hour 2 RNFL) and test-retest variability between 2.41 (for average RNFL) and 9.29 microm (for clock hour 6 RNFL). The repeatability was higher than that previously reported for time-domain OCT.
In eyes with clear media highly repeatable measurements of the RNFL thickness can be obtained by SD-OCT both before and after mydriasis.
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