Host and tissue tropisms of avian influenza A viruses

Wild birds are the natural reservoirs of Influenza A viruses (IAVs) which cause occasional pandemics and seasonal epidemics. Avian IAVs can be transmitted from wild birds to domestic poultry, low mammals, and humans. It is well accepted that avian IAVs prefer to sialic acids (Sia) α2,3-linked galactose (SAα2,3-Gal), whereas human IAVs to α2,6-linked galactose (SAα2,6-Gal). However, SAα2,3-Gal in wild bird tissues is widely distributed with little variation while some subtypes of avian IAVs have species preference. The different isolation rates among wild bird species cannot be explained by avian IAVs binding to SAα2,3-Gal alone. Specifically, this dissertation had the following aims: Firstly, to determine distribution of glycan receptors across respiratory and gastrointestinal tissues of wild birds and domestic poultry; Secondly, to determine the viral-receptor binding specificity of avian IAVs; Thirdly, to understand the role of glycan motifs in shaping virus evolution during the natural history of IAVs, especially from wild bird to poultry transmission. We found that avian H7 and H10 viruses acquired the binding ability to SAα2,6-Gal without adaptation, furthermore, we evaluated one of these H10 virus that possess the ability of binding to SAα2,6-Gal in ferret model and found it could cause aerosol and contact transmissions. On the other hand, H7 viruses have strong binding avidity to SLex which are present widely in epithelial cells of chicken trachea, which could facilitate the transmission of avian H7 viruses from waterfowl to poultry. Lastly, we found that H7 viruses from waterfowl bound both Neu5Ac and Neu5Gc while chicken isolates from China only prefer to Neu5Ac. Of interest, we found Neu5Gc was found in mallards but not in chickens, which indicated that viruses reduce or lost binding ability to Neu5Gc by adapting in chicken. In summary, this dissertation focused on certain subtypes of avian IAVs, which have caused threats to domestic poultry and public health, and primary avian species for influenza risk. The glycan substructures may play an important role in avian IAVs transmission and adaptation. The knowledge derived from this dissertation will help identify species for influenza surveillance in wild birds and facilitate risk assessment of avian IAVs

Treatment of insomnia in myasthenia gravis—A prospective study on non-benzodiazepine hypnotics in the treatment of myasthenia gravis patients with insomnia

ObjectivesThis study aimed to evaluate the efficacy and safety of non-benzodiazepine hypnotics in the treatment of myasthenia gravis (MG) patients with insomnia.MethodsThis is a prospective longitudinal study. Outpatients who met the criteria for stable MG and insomnia diagnosis according to the International Classification of Sleep Disorders (third edition) were included in the study. They took a regular dose of non-benzodiazepine hypnotics (zolpidem 10 mg per night or zopiclone 7.5 mg per night) based on their own preferences. Patients received psychotherapy (including sleep health education) and were followed up for 4–5 weeks. Cases with lung diseases, respiratory disorders, or inappropriate use of hypnotic medications were excluded. The primary outcome is the difference in total Pittsburgh Sleep Quality Index (PSQI) score between baseline and the end of follow-up period. Secondary outcomes include the difference in Myasthenia Gravis Activities of Daily Living (MG-ADL) score, 7-item Generalized Anxiety Disorder Questionnaire (GAD-7), and the Patient Health Questionnaire-9 (PHQ-9) between baseline and the end of follow-up period and the safety of medication.ResultsA total of 75 MG patients with insomnia were included in this study. After 4–5 weeks of treatment, the total PSQI score and MG-ADL score were lower than baseline (p < 0.01). No patients had an increased MG-ADL score. The incidence rate of adverse events was 16.0% (12 cases), including dizziness (6 cases, 8.0%), drowsiness (3 cases, 4.0%), fatigue (2 cases, 2.7%), and nausea (1 case, 1.3%), all of which were mild. No patients had new onset breathing disorders.ConclusionNon-benzodiazepine hypnotics are safe and effective for stable MG patients who need insomnia treatment

Association of gestational age at birth with subsequent suspected Developmental Coordination Disorder in early childhood

Importance. It remains unknown whether children born at different degrees of prematurity, early-term and post-term might have a higher risk of developing Developmental Coordination Disorder (DCD) compared to completely full-term children (39-40 gestational weeks). Objective. To differentiate between suspected DCD in children with different gestational ages based on a national representative sample in China. DESIGN, SETTING, AND PARTICIPANTS We conducted a retrospective cohort study in China from 2018 to 2019. A total of 152,433 children from 2,403 public kindergartens in 551 cities of China aged 3-5 years old were included in the final analysis. The association between gestational age and motor performance was investigated. A multi-level regression model was developed to determine the strength of association for different gestational ages associated with suspected DCD when considering kindergartens as clusters. Main outcomes and measures. Children’s motor performance was assessed using the Little Developmental Coordination Disorder Questionnaire (LDCDQ), completed by parents. Gestational age was determined according to the mother’s medical records. Results. Of the 152,433 children aged 3-5 years old, 80,370 (52.7%) were male, and 72,063 (47.3%) were female. There were 45,052 children aged 3 years old (29.6%), 59,796 aged 4 years old(39.2%), and 47,585 children aged 5 years old (31.2%). The LDCDQ total scores for very-preterm (β=-1.74, 95%CI: -1.98, 1.50; p<0.001), moderately-preterm (β=-1.24, 95%CI: -1.60, -0.89; p<0.001), late-preterm (β=-0.92, 95%CI: -1.08, -0.76; p<0.001), early-term (β=-0.36, 95%CI: -0.46, -0.25; p<0.001) and post-term children (β=-0.47, 95%CI: -0.67, -0.26; p<0.001) were significantly lower than full-term children when adjusting for child, family and maternal health characteristics. The very-preterm (OR=1.35, 95%CI: 1.23,1.48; p<0.001), moderately-preterm (OR=1.18, 95%CI: 1.02, 1.36; p<0.001), late-preterm (OR =1.24, 95%CI: 1.16,1.32; p<0.001), early-term (OR =1.11, 95%CI: 1.06,1.16; p<0.001) and post-term children (OR =1.167, 95%CI: 1.07, 1.27; p<0.001) were more likely to fall in the suspected Developmental Coordination Disorder (DCD) category on the LDCDQ compared with completely full-term children after adjusting for the same characteristics. The associations between different gestational ages and suspected DCD were stronger in boys and older (5 year old) children (each p<0.05). Conclusions and relevance. We found significant associations between every degree of prematurity at birth, early-term and post-term birth with suspected DCD when compared with full-term birth. Our findings have important implications for understanding motor development in children born at different gestational ages. Long-term follow-up and rehabilitation interventions should be considered for early- and post-term born children

Tissue Tropisms of Avian Influenza A Viruses Affect Their Spillovers from Wild Birds to Pigs

Wild aquatic birds maintain a large, genetically diverse pool of influenza A viruses (IAVs), which can be transmitted to lower mammals and, ultimately, humans. Through phenotypic analyses of viral replication efficiency, only a small set of avian IAVs were found to replicate well in epithelial cells of the swine upper respiratory tract, and these viruses were shown to infect and cause virus shedding in pigs. Such a phenotypic trait of the viral replication efficiency appears to emerge randomly and is distributed among IAVs across multiple avian species and geographic and temporal orders. It is not determined by receptor binding preference but is determined by other markers across genomic segments, such as those in the ribonucleoprotein complex. This study demonstrates that phenotypic variants of viral replication efficiency exist among avian IAVs but that only a few of these may result in viral shedding in pigs upon infection, providing opportunities for these viruses to become adapted to pigs, thus posing a higher potential risk for creating novel variants or detrimental reassortants within pig populations

Time-Dependent Proinflammatory Responses Shape Virus Interference during Coinfections of Influenza A Virus and Influenza D Virus

Both influenza A virus (IAV) and influenza D virus (IDV) are enzootic in pigs. IAV causes approximately 100% morbidity with low mortality, whereas IDV leads to only mild respiratory diseases in pigs. In this study, we performed a series of coinfection experiments in vitro and in vivo to understand how IAV and IDV interact and cause pathogenesis during coinfection. The results showed that IAV inhibited IDV replication when infecting swine tracheal epithelial cells (STECs) with IAV 24 or 48 h prior to IDV inoculation and that IDV suppressed IAV replication when IDV preceded IAV inoculation by 48 h. Virus interference was not identified during simultaneous IAV/IDV infections or with 6 h between the two viral infections, regardless of their order. The interference pattern at 24 and 48 h correlated with proinflammatory responses induced by the first infection, which, for IDV, was slower than for IAV by about 24 h. The viruses did not interfere with each other if both infected the cells before proinflammatory responses were induced. Coinfection in pigs further demonstrated that IAV interfered with both viral shedding and virus replication of IDV, especially in the upper respiratory tract. Clinically, coinfection of IDV and IAV did not show significant enhancement of disease pathogenesis, compared with the pigs infected with IAV alone. In summary, this study suggests that interference during coinfection of IAV and IDV is primarily due to the proinflammatory response; therefore, it is dependent on the time between infections and the order of infection. This study facilitates our understanding of virus epidemiology and pathogenesis associated with IAV and IDV coinfection

Pathogenicity and transmission of a swine influenza A(H6N6) virus

Subtype H6 influenza A viruses (IAVs) are commonly detected in wild birds and domestic poultry and can infect humans. In 2010, a H6N6 virus emerged in southern China, and since then, it has caused sporadic infections among swine. We show that this virus binds to α2,6-linked and α2,3-linked sialic acids. Mutations at residues 222 (alanine to valine) and 228 (glycine to serine) of the virus hemagglutinin (HA) affected its receptor-binding properties. Experiments showed that the virus has limited transmissibility between ferrets through direct contact or through inhalation of infectious aerosolized droplets. The internal genes of the influenza A(H1N1)pdm09 virus, which is prevalent in swine worldwide, increases the replication efficiency of H6N6 IAV in the lower respiratory tract of ferrets but not its transmissibility between ferrets. These findings suggest H6N6 swine IAV (SIV) currently poses a moderate risk to public health, but its evolution and spread should be closely monitored.Emerging Microbes & Infections (2017) 6, e17; doi:10.1038/emi.2017.3; published online 12 April 201