Adamantanes (amantadine and rimantadine) have been used to prevent and treat influenza A virus infections for many years; however, resistance to these drugs has been widely reported in the world. To investigate the frequency and distribution of M2 gene mutations in adamantane-resistant influenza variants circulated in the world between 1902 and 2013, 31251 available M2 protein sequences from different HA-subtype influenza A viruses (H1–H17) were analyzed and adamantane resistance-associated mutations were compared (L26F, V27A, A30T, A30V, S31N, G34E, and L38F). We find that 45.2% (n = 14132) of influenza A (H1–H17) viruses circulating globally were resistant to adamantanes, and the vast majority of resistant viruses (95%) bear S31N mutations. Whereas, only about 1% have V27A mutations and other mutations (L26F, A30T, G34E, and L38F) were extremely rare (their prevalence appeared to be < 0.2%). Our results confirm that H1, H3, H5, H7, H9, and H17 subtype influenza A viruses exhibit high-level resistance to adamantanes. In contrast, the appearance of adamantane-resistant mutants in H2, H4, H6, H10, and H11 subtypes was rare. However, no adamantane resistance viruses were identified among other HA subtypes (H8, H12–H16). Our findings indicate that the frequency and distribution of adamantane-resistant influenza variants varied among different HA subtypes, host species, years of isolation, and geographical areas. This comprehensive study raises concerns about the increasing prevalence of adamantane-resistant influenza A viruses and highlights the importance of monitoring the emergence and worldwide spread of adamantane-resistant variants.
Severe fever with thrombocytopenia syndrome (SFTS) was firstly discovered in China in 2010, followed by several reports from many other countries worldwide. SFTS virus (SFTSV) has been identified as the causative agent of the disease and has been recognized as a public health threat. This novel Bunyavirus belongs to the Phlebovirus genus in the family Bunyaviridae. This review also describes the different aspects of virology, pathogenesis, epidemiology, and clinical symptoms on the basis of the published article surveillance data and phylogenetic analyses of viral sequences of large, medium, and small segments retrieved from database using mega 5.05, simplot 3.5.1, network 4.611, and epi information system 3.5.3 software. SFTS presents with fever, thrombocytopenia, leukocytopenia, and considerable changes in several serum biomarkers. The disease has 10 ∼ 15% mortality rate, commonly because of multiorgan dysfunction. SFTSV is mainly reported in the rural areas of Central and North-Eastern China, with seasonal occurrence from May to September, mainly targeting those of ≥50 years of age. A wide range of domesticated animals, including sheep, goats, cattle, pigs, dogs, and chickens have been proven seropositive for SFTSV. Ticks, especially Haemaphysalis longicornis, are suspected to be the potential vector, which have a broad animal host range in the world. More studies are needed to elucidate the vector–animal–human ecological cycle, the pathogenic mechanisms in high level animal models and vaccine development. © 2013 The Authors. Reviews in Medical Virology published by John Wiley & Sons, Ltd.
Whole Pacific oysters (Crassostrea gigas) were processed using high-pressure processing (HPP) treatment from 207 to 310 MPa at 0, 1, and 2 min and stored at Ͻ Ͻ Ͻ Ͻ Ͻ 4 Њ Њ Њ Њ ЊC and evaluated over 27 d. The pH of HPP samples decreased slightly from 6.3 to 5.8 during storage while the control (hand-shucked oysters) dropped to pH 4.1. Moisture content of the controls decreased slightly while HPP samples increased slightly. Pressure treatment did not significantly inhibit lipase activity during the shelf-life study. HPP reduced initial microbial load by 2 to 3 logs and counts remained at a reduced level through the storage study. Descriptive evaluation showed that HPP-treated oysters received higher quality scores than controls during the storage trial.
H9N2 influenza A viruses have become established worldwide in terrestrial poultry and wild birds, and are occasionally transmitted to mammals including humans and pigs. To comprehensively elucidate the genetic and evolutionary characteristics of H9N2 influenza viruses, we performed a large-scale sequence analysis of 571 viral genomes from the NCBI Influenza Virus Resource Database, representing the spectrum of H9N2 influenza viruses isolated from 1966 to 2009. Our study provides a panoramic framework for better understanding the genesis and evolution of H9N2 influenza viruses, and for describing the history of H9N2 viruses circulating in diverse hosts. Panorama phylogenetic analysis of the eight viral gene segments revealed the complexity and diversity of H9N2 influenza viruses. The 571 H9N2 viral genomes were classified into 74 separate lineages, which had marked host and geographical differences in phylogeny. Panorama genotypical analysis also revealed that H9N2 viruses include at least 98 genotypes, which were further divided according to their HA lineages into seven series (A–G). Phylogenetic analysis of the internal genes showed that H9N2 viruses are closely related to H3, H4, H5, H7, H10, and H14 subtype influenza viruses. Our results indicate that H9N2 viruses have undergone extensive reassortments to generate multiple reassortants and genotypes, suggesting that the continued circulation of multiple genotypical H9N2 viruses throughout the world in diverse hosts has the potential to cause future influenza outbreaks in poultry and epidemics in humans. We propose a nomenclature system for identifying and unifying all lineages and genotypes of H9N2 influenza viruses in order to facilitate international communication on the evolution, ecology and epidemiology of H9N2 influenza viruses.
To trace the source of the avian H7N9 viruses, we collected 99 samples from 4 live poultry markets and the family farms of 3 patients in Hangzhou city of Zhejiang province, China. We found that almost all positive samples came from chickens and ducks in live poultry markets. These results strongly suggest that the live poultry markets are the major source of recent human infections with H7N9 in Hangzhou city, Zhejiang province of China. Therefore, control measures are needed, not only in the domestic bird population, but also in the live poultry markets to reduce human H7N9 infection risk.
Human infection with avian influenza A H5N1 viruses can cause severe diseases with high mortality rate and continues to pose a significant threat to global public health. Rapid diagnosis is needed for identifying the types of influenza viruses for making timely treatment decisions. Here, we demonstrate absolute quantification of H5-subtype influenza viruses by digital loop-mediated isothermal amplification (dLAMP) on our recently developed cross-interface emulsification (XiE) method. Our results show that XiE-based dLAMP is highly specific and displays comparable sensitivity to real-time PCR (qPCR) and digital PCR (dPCR). Notably, dLAMP is more tolerant to inhibitory substances than PCR methods and demonstrated similar detection efficiency to qPCR for real H5N1 samples. Therefore, it can serve as a robust and precise alternative to qPCR or dPCR and is especially suitable for environmental and clinical samples with hard-to-remove contaminants. We believe that our dLAMP method offers great potential for rapid and accurate diagnosis of influenza and other infectious diseases.
Injectable and biodegradable supramolecular hydrogels were prepared by nucleobase (adenine/thymine)terminated poly(ethylene oxide)s (A-PEG-A/T-PEG-T) and a-cyclodextrin (a-CD). The supramolecular hydrogels were thoroughly characterized by WXRD, rheometer, and SEM. The gelation time depended on the molecular weight of PEG and the concentration of polymer precursors. The rheological studies showed enhanced elastic modulus (G 0 ) of hydrogels, because of the hydrogen-bonding between A and T acting as additional network junctions. In vitro evaluation showed that the supramolecular hydrogels have acceptable biocompatibility, and are suitable for sustained and controlled release of loaded antitumor drugs. Gel formation was also confirmed when the supramolecular hydrogels were subcutaneously injected into rats. In addition, in vivo experiments employing U14 cancer cell xenograftbearing mice showed that the intratumoral injection of a DOX-loaded A-PEG-A/T-PEG-T/a-CD gel inhibited tumor growth more effectively than that of free DOX, DOX-loaded PEG/a-CD gel, saline or gel alone. Hence, such a simple and convenient anti-cancer drug delivery system of a A-PEG-A/T-PEG-T/a-CD supramolecular hydrogel would be a promising candidate for many biomedical applications, especially in the area of the chemotherapy of solid tumors.
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