The emergence of human infection with a novel H7N9 influenza virus in China raises a pandemic concern. Chicken H9N2 viruses provided all six of the novel reassortant’s internal genes. However, it is ...not fully understood how the prevalence and evolution of these H9N2 chicken viruses facilitated the genesis of the novel H7N9 viruses. Here we show that over more than 10 y of cocirculation of multiple H9N2 genotypes, a genotype (G57) emerged that had changed antigenicity and improved adaptability in chickens. It became predominant in vaccinated farm chickens in China, caused widespread outbreaks in 2010–2013 before the H7N9 viruses emerged in humans, and finally provided all of their internal genes to the novel H7N9 viruses. The prevalence and variation of H9N2 influenza virus in farmed poultry could provide an important early warning of the emergence of novel reassortants with pandemic potential.
Two velogenic Newcastle disease viruses (NDV) obtained from outbreaks in domestic ducks in China were characterized in this study. Phylogenetic analysis revealed that both strains clustered with the ...class II viruses, with one phylogenetically close to the genotype VII NDVs and the other closer to genotype IX. The deduced amino acid sequence of the cleavage site of the fusion (F) protein confirmed that both isolates contained the virulent motif (112)RRQK/RRF(117) at the cleavage site. The two NDVs had severe pathogenicity in fully susceptible chickens, resulting in 100% mortality. One of the isolates also demonstrated some pathogenicity in domestic ducks. The present study suggests that more than one genotype of NDV circulates in domestic ducks in China and viral transmission may occur among chickens and domestic ducks.
A virulent avian infectious bronchitis virus (IBV) was isolated from 30-day-old broiler chickens that exhibited respiratory symptoms, nephropathologic lesions, and a high proportion of deaths in the ...People's Republic of China during 2005. The strain, designated YN, was genetically and pathologically characterized. Phylogenetic analysis showed that YN and most of the previously characterized IBV isolates found in China were phylogenetically classified into 2 main genetic clusters. The YN isolate caused severe lesions and resulted in deaths of 65% in experimental infections of 30-day-old specific-pathogen-free chickens. Tracheal and severe kidney lesions developed in all infected birds, confirming the ability of YN strain to induce both respiratory and renal disease. IBV antigens were detected by immunohistochemical analysis in the trachea, lung, kidney, and bursa, consistent with histopathologic observations, virus isolation, and reverse transcription PCR detection. We showed that YN IBV exhibits severe pathogenicity in chickens, and that similar viruses are prevalent in China.
Twenty Newcastle disease virus (NDV) isolates from infected chicken flocks during 2001 to 2009 in China were biologically and genetically characterized. All the 20 NDVs were categorized into ...velogenic (
n
=
17) and lentogenic (
n
=
3) viruses, respectively, according to the mean death time (MDT) of chicken embryos. Velogenic viruses carry the motif
112R-R-Q-K-R/F
117 (
n
=
14) or
112G-R-Q-G-R/L
117 (
n
=
3) at the F0 cleavage site, while all the lentogenic virus had a sequence motif of
112G-R-Q-G-R/L
117 (
n
=
3) at the same site. Phylogenetic analysis revealed that at least three distinct genotypes (genotypes I, II and VII) existed in chicken flocks in China and VIId of genotype VII were mainly responsible for the present ND panzootic. Two natural recombinants (XD/Shandong/08 and QG/Hebei/07) were supposed and identified by the SimPlot program, and their two parental-like strains might be from the NDV vaccine lineage and VIId velogenic lineage respectively. The results indicate that recombination play a role in NDV evolution and the live vaccines have capacity to boost NDV evolution by homologous recombination with circulating virus.
High rates of mortality for Pekin ducklings have been recorded in several duck farms in China since 2006. Dead ducklings were characterized by spleen necrosis, suggesting microbial infection as a ...cause of disease. Laboratory investigations led to the isolation of a virus strain from the spleen tissues of dead ducklings, designated DRV-HC. Subsequent experimental infections with DRV-HC resulted in marked spleen necrosis in the ducklings similar to those observed in the natural outbreaks. Electron microscopy of the cultured DRV-HC revealed viral particles that were non-enveloped and icosahedral with a mean diameter of approximately 72
nm. Agar gel precipitating tests showed that the isolate shared a common group-specific antigen with chicken reovirus S1133. DNA sequencing revealed that this isolate was closely related to Muscovy duck reoviruses. Experimental infection with DRV-HC resulted in death of young chicks with necrotic foci in the liver and spleen. To the best of our knowledge, this is the first report of the isolation of a duck reovirus with high virulence in Pekin ducklings and SPF chickens.
Between 2003 and 2005, four strains of infectious bronchitis virus (IBV) were isolated from the vaccinated chicken flocks in China. The results from chicken embryo cross-neutralization assays showed ...that all the four isolates were relative to strain A2 of IBV, which was isolated in 1996 in Beijing and related to strain 4/91. The S1 gene of the spike protein was amplified and sequenced. The nucleotide and amino acid sequence of the S1 gene had a similar degree of identity (88.98–99.28%) among the four Chinese IBV isolates. The identity of the S1 protein gene between the four Chinese IBV isolates and 14 strains of other IBVs varied from 70.06 to 81.59%. Phylogenetic analysis suggested that there are at least four groups of IBVs circulating in China and the disease outbreaks might have been caused by infection of multiple strains of IBV.
Morganella morganii, a Gram-negative rod commonly found in the intestines of humans and other animals, is here confirmed to cause a fatal infection in chickens by isolation and identification of the ...bacteria, 16S rRNA gene sequencing, and experimental infection. This is the first case of M. morganii infection in chickens.
Ultrasonic water meters offer a number of advantages such as non-intrusiveness, low pressure loss, high accuracy, low power consumption and long service life, which make them a viable option for the ...next generation of smart water meters. However, the existing ultrasonic water meters have difficulties in balancing the range and accuracy. Therefore, in order to address this issue, this study proposes a novel ultrasonic water meter featured with high-precision and wide-range. First of all, the flow measurement principle of the ultrasonic time difference method is investigated, and a flow measurement model that includes the parameter of radial transit time (TD) is developed. The ultrasonic water meter is designed based on comprehensive consideration of the three aspects of hardware, software and algorithms, and a series of experiments are conducted to verify the performance of the water meter. Eighteen verification test points with the flow range of 0.015–4.509 m3/h are carried out, the results of which suggest that the accuracy level of the ultrasonic water meter reaches 0.5, with the repeatability of 0.09%, and the range ratio of 300:1, indicating the achievement of the design goal of high-precision and wide-range.
•This study proposes a novel ultrasonic water meter featured with high-precision and wide-range.•A flow measurement model that includes the parameter of radial transit time (TD) is developed.•The ultrasonic water meter is designed, and experiments are conducted to verify the performance of the water meter.•The accuracy level of the ultrasonic water meter reaches 0.5, with the repeatability of 0.09%, and the range ratio of 300:1.
Population growth and global industrialization cause a dramatic increase in the amount of sewage sludge produced annually worldwide from Municipal and Industrial Wastewater treatment. The efficient ...measurement of sewage, which is a typical solid-liquid two-phase flow, has become an important issue that requires to be urgently addressed. In this study, an improved Ultrasonic Doppler Velocimetry (UDV) is proposed to optimize the probe design and hardware design, which reduces the influence of working frequency and echo reverberation on accuracy and improves the stability of the system. A Doppler peak extraction and superposition method is also put forward to correct the offset of Doppler peak frequency. In this paper, Particle Image Velocimetry (PIV) is used to calibrate the UDV system to modify the measurement model of ultrasonic Doppler liquid-solid two-phase flow, and dynamic experiments are carried out in a vertical steel pipe with inner diameter of 50 mm at different flow conditions. The results show that the accuracy and stability of UDV measurement system are greatly improved, with a maximum relative error of 1.49%.
•In this study, ultrasonic Doppler velocimetry (UDV) was used to achieve high-efficiency measurement of solids velocity in sewage.•The PIV flow rate measurement system has high accuracy and can realize online calibration for UDV.•The dual-modality UDV-PIV system proposed in this paper has a significant sewage treatment effect, achieving a maximum relative error of 1.49%.•The proposed dual modality system can have a great potential for measuring industrial solid-liquid flow with excellent precision.
Two Newcastle disease viruses (NDV), designated QG/Hebei/07 and XD/Shandong/08, were isolated from infected chicken flocks in China in 2007 and 2008, respectively. The results of phylogenetic and ...recombination analyses on complete NDV genome sequences (excluding terminal segments) show that the QG/Hebei/07 isolate had evidence of recombination in the M and F genes, and recombination in the XD/Shandong/08 isolate in the F, L genes and the non-coding region between the HN and L genes. These two naturally-occurring recombinants we found to be descended from at least three putative parents from vaccine and circulating virus lineages. Moreover, we found that evidence that homologous recombination also occurred between NDV viruses of chicken and swine lineages, while the major putative parent is likely to have been derived from the chicken avirulent vaccine lineage. This study suggests that homologous recombination can occur in all coding and non-coding regions of the NDV genome and a live vaccine strain is capable of recombination with circulating viruses resulting in significant genetic change. The potential role of swine-origin viruses in the evolution of virulent NDV warrants further investigation.
PDF
