Immunogenicity and Protective Capacity of Sugar ABC Transporter Substrate-Binding Protein against Streptococcus suis Serotype 2, 7 and 9 Infection in Mice.

Background:Streptococcus suis (S. suis) is a Gram-positive bacterium that causes substantial disease in pigs. S. suis is also an emerging zoonoses in humans, primarily in Asia, through the consumption of undercooked pork and the handling of infected pig meat as well as carcasses. The complexity of S. suis epidemiology, characterized by the presence of multiple bacterial serotypes and strains with diverse sequence types, identifies a critical need for a universal vaccine with the ability to confer cross-protective immunity. Highly conserved immunogenic proteins are generally considered good candidate antigens for subunit universal vaccines. Methods: In this study, the cross-protection of the sugar ABC transporter substrate-binding protein (S-ABC), a surface-associated immunogenic protein of S. suis, was examined in mice for evaluation as a universal vaccine candidate. Results: S-ABC was shown to be highly conserved, with 97% amino acid sequence identity across 31 S. suis strains deposited in GenBank. Recombinantly expressed S-ABC (rS-ABC) was recognized via rabbit sera specific to S. suis serotype 2. The immunization of mice with rS-ABC induced antigen-specific antibody responses, as well as IFN-γ and IL-4, in multiple organs, including the lungs. rS-ABC immunization conferred high (87.5% and 100%) protection against challenges with S. suis serotypes 2 and 9, demonstrating high cross-protection against these serotypes. Protection, albeit lower (50%), was also observed in mice challenged with S. suis serotype 7. Conclusions: These data identify S-ABC as a promising antigenic target within a universal subunit vaccine against S. suis.

Epidemiological Investigation of Goose Astrovirus in Hebei Province, China, 2019-2021.

The goose astrovirus (GAstV), a key pathogen causing visceral gout and high mortality in geese, has spread widely in China, with frequent outbreaks in recent years. Outbreaks and transmissions of this virus have been reported across China, causing considerable economic losses to the goose industry worldwide, with losses exceeding tens of billions in China alone. However, there is still no effective prevention strategy against this virus. Therefore, continuous monitoring of the genetic diversity of dominant GAstV strains is crucial for developing targeted vaccines and appropriate therapeutics. As a crucial region for goose breeding in China, Hebei Province has previously lacked reports on the epidemiology of GAstV. Hence, investigating the epidemiology of GAstV in Hebei Province is highly important. From January 2019 to December 2021, 474 samples suspected of having a GAstV infection were collected in Hebei Province in this study. Through detailed histological observations, pathological examinations, virus isolation and identification, and genetic diversity analysis, we found that GAstV-2 has become the predominant circulating genotype. However, the presence of GAstV-1 and mixed infections cannot be ignored and should receive increased attention. The findings of this study not only deepened our understanding of GAstV in waterfowl in China but also provided scientific evidence for developing effective prevention and control measures, thereby promoting the healthy development of the goose industry in China.

Pharmacokinetics and antioxidant activity of dihydrocaffeic acid grafted chitosan nanomicelles loaded with chicoric acid in broilers.

Chicoric acid (CA) is a natural nutrient found in plants, showcasing diverse biological activities, including anti-inflammatory and antioxidant properties. Despite its valuable properties, CA faces limitations in bioavailability and susceptibility to oxidative breakdown during utilization. Previous research introduced synthesized dihydrocaffeic acid grafted chitosan self-assembled nanomicelles (DA-g-CS), demonstrating its potential to enhance CA absorption. This study aims to investigate the pharmacokinetics, tissue distribution, and antioxidant activity of both CA and DA-g-CS loaded CA (DA-g-CS/CA) in broilers. An IPEC-J2 cell model was established and evaluated to delve deeper into the transport mechanism and antioxidant potential. The in vivo pharmacokinetic analysis in broilers highlighted a substantial difference: the maximum plasma concentration (Cmax) of DA-g-CS/CA exceeded CA by 2.6-fold, yielding a notable increased relative bioavailability to 214%. This evidence underscores the significant enhancement in CA's oral absorption, facilitated by DA-g-CS. The collective evaluation outcomes affirm the successful development of the cell model, indicating its suitability for drug transporter experiments. The findings from the intestinal transit analysis revealed that both CA and DA-g-CS/CA underwent passive entry into IPEC-J2 cells. Notably, the cellular uptake rate of DA-g-CS loaded with CA was significantly amplified, reaching 2.1 times higher than that of CA alone. Intracellular transport mechanisms involved microtubules, lysosomes, and the endoplasmic reticulum, with an additional pathway involving the endoplasmic reticulum observed specifically for DA-g-CS/CA, distinguishing it from CA. Moreover, the results from both in vivo and in vitro antioxidant assessments highlight the potent antioxidant activity of DA-g-CS/CA, showcasing its efficacy in preventing and treating cellular damage induced by oxidative stress. In summary, these findings underscore the significant enhancement of CA's efficacy facilitated by DA-g-CS, establishing a robust theoretical foundation for the prospective application of CA within livestock and poultry farming.

Hepatic Sinusoid Capillarizate via IGTAV/FAK Pathway Under High Glucose.

The incidence of diabetic patients with non-alcoholic fatty liver disease (NAFLD) is continuously increasing worldwide. However, the specific mechanisms of NAFLD patients with diabetes are still not clear. Recent studies have indicated that integrins play an important role in NAFLD. In this study, we considered the relationship between integrin αv (IGTAV)/FAK pathway and sinusoidal capillarization. We investigated the difference between the expression of IGTAV, laminin (LN), focal adhesion kinase (FAK), and phosphor-FAK protein in human liver sinusoidal endothelial cells (HLSECs) to explore the specific mechanisms of the diseases of NAFLD with diabetes under high glucose. We cultured and identified the HLSECs and constructed the recombinant lentivirus vector with IGTAV shRNA by quantitative real-time PCR (qRT-PCR) to silence the IGTAV gene. Cells were divided into groups of 25 mmol/L glucose and 25 mmol/L mannitol. We measured the protein levels of IGTAV, LN, FAK, and phosphor-FAK by western blot at 2 h, 6 h, and 12 h before and after IGTAV gene silencing. The lentivirus vector was successfully constructed with IGTAV shRNA. The HLSECs under high glucose were observed by scanning electron microscope. SPSS19.0 was used for statistical analysis. High glucose significantly increased the expression of IGTAV, LN, and phosphor-FAK protein in HLSECs; the shRNA IGTAV could effectively inhibit the expression of phosphor-FAK and LN at 2 h and 6 h. Inhibition of the phosphor-FAK could effectively decrease the expression of LN in HLSECs at 2 h and 6 h under high glucose. Inhibition of IGTAV gene of HLSECs under high glucose could improve hepatic sinus capillarization. Inhibition of IGTAV and phosphor-FAK decreased the expression of LN. High glucose led to hepatic sinus capillarization via IGTAV/ FAK pathway.

Analysis of Resistance Gene Diversity in the Intestinal Microbiome of Broilers from Two Types of Broiler Farms in Hebei Province, China.

The crucial reservoir of antibiotic resistance genes (ARGs) within the chicken intestinal microbiome poses a serious threat to both animal and human health. In China, the overuse of antibiotics has significantly contributed to the proliferation of ARGs in the chicken intestinal microbiome, which is a serious concern. However, there has been relatively little research on the diversity of resistance genes in the chicken intestinal microbiome since the implementation of the National Pilot Work Program for Action to Reduce the Use of Veterinary Antimicrobial Drugs in China. The objective of this study was to analyze the diversity of antibiotic resistance genes carried by the chicken intestinal microbiome in both standard farms (SFs), which implement antibiotic reduction and passed national acceptance, and nonstandard farms (NSFs), which do not implement antibiotic reductions, in Hebei Province. Fresh fecal samples of broiler chickens were collected from SFs (n = 4) and NSF (n = 1) and analyzed using high-throughput qPCR technology. Our findings revealed that all five farms exhibited a wide range of highly abundant ARGs, with a total of 201 ARGs and 7 MGEs detected in all fecal samples. The dominant ARGs identified conferred resistance to aminoglycosides, macrolide-lincosamide-streptomycin B (MLSB), and tetracycline antibiotics. Cellular protection mechanisms were found to be the primary resistance mechanism for these ARGs. The analysis of the co-occurrence network demonstrated a significant positive correlation between the abundance of MGEs and ARGs. The SF samples showed a significantly lower relative abundance of certain ARGs than the NSF samples (p < 0.05). The results of this study show that the abundance of ARGs demonstrated a downward trend after the implementation of the National Pilot Work Program for Action to Reduce the Usage of Veterinary Antimicrobial Drugs in Hebei Province, China.

Identification, Typing, and Drug Resistance Analysis of Escherichia coli in Two Different Types of Broiler Farms in Hebei Province.

Hebei Province is an important area for breeding broiler chickens in China, but the antimicrobial resistance and prevalence of Escherichia coli (E. coli) are still unclear. A total of 180 cloacal samples from broiler farms in Hebei Province were collected and used for the isolation and identification of E. coli. The isolates were subjected to resistance phenotyping, resistance profiling, and genotyping, and some multiresistant strains were subjected to multilocus sequence typing (MLST). The results showed that 175 strains were isolated. Among both types of broiler farms, the ampicillin resistance rate was the highest, and the meropenem resistance rate was the lowest. Serious multiresistance was present in both types of broiler farms. Thirty strains of multidrug-resistant E. coli were typed by MLST to obtain a total of 18 ST types, with ST10 being the most prevalent. This study was to simply analyze the antimicrobial resistance and prevalence of E. coli in broiler chickens in Hebei Province after the implementation of the pilot work program of action to reduce the use of veterinary antimicrobials in standard farms (SFs) and nonstandard farms (NSFs). This study will provide a research basis and data support for the prevention and control of E. coli in Hebei.

Dihydrocaffeic acid grafted chitosan self-assembled nanomicelles with enhanced intestinal transport and antioxidant properties of chicoric acid.

Chicoric acid (CA) plays a crucial role as a functional factor within the realm of foods, showcasing a wide array of bioactivities. Nevertheless, its oral bioavailability is significantly limited. To optimize the intestinal absorption and bolster the antioxidant capacity of CA, a water-soluble dihydrocaffeic acid grafted chitosan copolymer (DA-g-CS) was synthesized using a conventional free radicals system, and subsequently utilized for the encapsulation of CA within self-assembled nanomicelles (DA-g-CS/CA). The average particle size of DA-g-CS/CA was 203.3 nm, while the critical micelle concentration was 3.98 × 10-4 mg/mL. Intestinal transport studies revealed that DA-g-CS/CA penetrated cells via the macropinocytosis pathway, exhibiting the cellular uptake rate 1.64 times higher than that of CA. This substantial enhancement in the intestinal transport of CA underscores the significant improvements achieved through DA-g-CS/CA delivery. The pharmacokinetic results demonstrated that DA-g-CS/CA exhibited a remarkable bioavailability 2.24 times that of CA. Furthermore, the antioxidant assessment demonstrated that DA-g-CS/CA exhibited exceptional antioxidant properties in comparison to CA. It demonstrated enhanced protective and mitigating effects in the H2O2-induced oxidative damage model, while also displaying a stronger emphasis on protective effects rather than attenuating effects. These findings aim to establish a solid theoretical foundation for the advancement of CA in terms of its oral absorption and the development of functional food products.

Effects of different laying periods on airborne bacterial diversity and antibiotic resistance genes in layer hen houses.

Poultry farms are a complex environment for close contact between humans and animals. Accumulating evidence has indicated that pathogens and drug resistance genes in chicken houses may pose a serious threat to public health and economic concerns. However, insufficient knowledge of the indoor aerosol microbiome and resistome profiles of layer hen houses hampers the understanding of their health effects. Environmental surveillance of antibiotic resistance may contribute to a better understanding and management of the human exposure risk of bioaerosols under the environmental conditions of chicken houses. In addition, the chicken house has a long operation cycle, and the bacterial diversity and antibiotic resistance genes of aerosols in different periods may be different. In this study, air samples were collected from 18 chicken houses on three farms, including the early laying period (EL), peak laying period (PL), and late laying period (LL). 16S rRNA gene sequencing and metagenomics were used to study the composition of the bacteria and resistome in aerosols of layer hen houses and the results showed that they varied with laying period. The highest alpha diversity of bacteria was observed in PL bioaerosols. The dominant bacterial phyla included Firmicutes, Bacteroidetes and Proteobacteria. Three potential pathogenic bacterial genera (Bacteroides, Corynebacterium and Fusobacterium) were found. The most abundant ARG type was aminoglycosides in all laying periods. In total, 22 possible ARG host genera were detected. ARG subtypes and abundance were both higher in LL. Network analysis also showed higher co-occurrence patterns between the bacteria and resistome in bioaerosols. The laying period plays an important role in the bacterial community and resistome in layer house aerosols.

Alterations of Spontaneous Cortical and Subcortical Activity in Type 2 Diabetes Mellitus with and without Depression.

INTRODUCTION: Type 2 diabetes mellitus (T2DM) patients with depression have a higher risk of complications and mortality than T2DM without depression. However, the exact neuropathophysiological mechanism remains unclear. Consequently, the current study aimed to investigate the alteration of cortical and subcortical spontaneous neural activity in T2DM patients with and without depression. METHODS: The demographic data, clinical variables, neuropsychological tests, and functional and anatomical magnetic resonance imaging of depressed T2DM (n = 47) of non-depressed T2DM (n = 59) and healthy controls (n = 41) were collected and evaluated. The correlation analysis, stepwise multiple linear regression, and receiver operating characteristic curve were performed for further analysis. RESULTS: Abnormal neural activities in the bilateral posterior cingulate cortex (PCC) and hippocampus were observed in depressed and non-depressed T2DM and the right putamen of the depressed T2DM. Interestingly, the subcortical degree centrality (DC) of the right hippocampus and putamen were higher in depressed than non-depressed T2DM. Furthermore, the cortical amplitude of low-frequency fluctuation (ALFF) in PCC, subcortical DC in the putamen of depressed T2DM, and hippocampus of non-depressed T2DM was correlated with cognitive scores. In contrast, the cortical fractional ALFF in PCC of non-depressed T2DM was correlated with depression scores. CONCLUSIONS: The abnormalities of spontaneous cortical activity in PCC and subcortical activity in the hippocampus might represent the neurobiological feature of cerebral dysfunction in T2DM. Notably, the altered subcortical activity in the right putamen might mainly associate with negative emotion in T2DM, which could be a promising biomarker for recognizing early cerebral dysfunction in depressed T2DM. This study provided a novel insight into the neuropathophysiological mechanism of brain dysfunction in T2DM with and without depression.

Subunit Vaccine Targeting Phosphate ABC Transporter ATP-Binding Protein, PstB, Provides Cross-Protection against Streptococcus suis Serotype 2, 7, and 9 in Mice.

Streptococcus suis is a significant pathogen in pigs and a newly emerging zoonotic agent in humans. The presence of multiple serotypes and strains with diversified sequence types in pig herds highlights the need for the identification of broadly cross-reactive universal vaccine antigen targets, capable of providing cross-protection against S. suis infection. Subunit vaccines based on the conserved proteins shared between different S. suis serotypes are potential candidates for such a universally protective vaccine. In the present study, phosphate ABC transporter ATP-binding protein PstB (PstB), an immunogenic protein of the S. suis bacterium, was expressed and purified, and then subjected to cross-protection evaluation in mice. The PstB protein showed nearly 100% amino acid similarity across a panel of 31 S. suis isolates representing different serotypes, which were collected from different countries. A recombinant PstB (rPstB) protein (S. suis serotype 2) was recognized by rabbit sera specific to this serotype, and induced high levels of IFN-γ and IL-4 in mice immunized with the recombinant protein. These cytokines are considered important for protection against S. suis infection. Immunization of mice with rPstB resulted in an 87.5% protection against challenge with S. suis serotype 2 and 9 strains, suggesting a high level of cross-protection for S. suis serotypes 2 and 9. A lower protection rate (62.5%) was observed in mice challenged with the S. suis serotype 7 strain. These data demonstrate that PstB is a promising target antigen for development as a component of a universal subunit vaccine against multiple S. suis serotypes.

Dual AuNPs detecting probe enhanced the NanoSPR effect for the high-throughput detection of the cancer microRNA21 biomarker.

The microRNA21 (miR-21), a specific tumor biomarker, is crucial for the diagnosis of several cancer types, and investigation of its overexpression pattern is important for cancer diagnosis. Herein, we report a low-cost, rapid, ultrasensitive, and convenient biosensing strategy for the detection of miR-21 using a nanoplasmonic array chip coupled with gold nanoparticles (AuNPs). This sensing platform combines the surface plasmon resonance effect of nanoplasmonics (NanoSPR) and the localized surface plasmon resonance (LSPR) effect, which allows the real-time monitoring of the subtle optical density (OD) changes caused by the variations in the dielectric constant in the process of the hybridization of the target miRNA. Using this method, the miRNA achieves a broad detection range from 100 aM to 1 µM, and with a limit of detection (LoD) of 1.85 aM. Furthermore, this assay also has a single-base resolution to discriminate the highly homologous miRNAs. More importantly, this platform has high throughput characteristics (96 samples can be detected simultaneously). This strategy exhibits more than 86.5 times enhancement in terms of sensitivity compared to that of traditional biosensors.

Quantitative lipidomics reveals lipid perturbation in the liver of fatty liver hemorrhagic syndrome in laying hens.

Fatty liver hemorrhagic syndrome (FLHS) is a metabolic disease that causes decreased egg production and even death in laying hens, which brings huge economic losses to the poultry industry. However, the pathogenesis of FLHS is unclear. The purpose of the present study was to identify the changes in lipid profile and the lipid species related to FLHS. In the present study, the FLHS disease model in Chinese commercial Jing Fen laying hens was induced by a high-energy low-protein diet. A lipidomics approach based on ultra-performance liquid chromatography-mass spectrometry coupled with multivariate statistical analysis was performed for the qualitative and quantitative analyses of the liver lipids. The results showed that a total of 29 lipid subclasses, including 1,302 lipid species, were detected and identified. Among them, the proportions of phosphatidylserine (Control/FLHS, 33.1% vs. 29.1%), phosphatidylethanolamine (22.7% vs. 15.5%), phosphatidylcholine (15.7% vs. 11.7%) and phosphatidylinositol (7% vs. 6%) were reduced, while triacylglycerol (7.1% vs. 18.3%) and diglyceride (3.9% vs. 11.7%) were increased. Between the Control and FLHS groups, distinct changes in lipid profile were observed in the score plots of principal component analysis and orthogonal partial least squares discriminant analysis. Twelve differential lipid species mainly involved in glycerophospholipid metabolism and linoleic acid metabolism were identified and considered to be related to the pathogenesis of FLHS. Fatty acid chain length and unsaturation were reduced, while the mRNA levels of elongation of very long chain fatty acids-2 (ELOVL2) were increased in the liver of laying hens with FLHS. Collectively, this study characterized the liver lipid profile and explored the changes in lipid species related to FLHS, which provided insights into the pathogenesis of FLHS from the view of lipid metabolism.

An ultra-sensitive and specific nanoplasmonic-enhanced isothermal amplification platform for the ultrafast point-of-care testing of SARS-CoV-2.

The novel mutations attributed by the high mutagenicity of the SARS-CoV-2 makes its prevention and treatment challenging. Developing an ultra-fast, point-of-care-test (POCT) protocol is critical for responding to large-scale spread of SARS-CoV-2 in public places and in resource-poor remote areas. Here, we developed a nanoplasmonic enhanced isothermal amplification (NanoPEIA) strategy that combines a nanoplasmonic sensor with isothermal amplification. The novel strategy provides an ideal easy-to operate detection platform for obtaining accurate, ultra-fast and high-throughput (96 samples can be tested together) data. For clinical samples with viral detection at Ct value <25, the entire process (including sample preparation, virus lysis, detection, and data analysis) can be completed within six minutes. The method is also appropriate for detection of SARS-CoV-2 γ-coronavirus mutants. The NanoPEIA method was validated using clinical samples from 21 patients with SARS-CoV-2 infection and 31 healthy individuals. The detection result on the 52 clinical samples for SARS-CoV-2 showed that the NanoPEIA platform had a 100% sensitivity for N and orf1ab genes, which was higher than those obtained using RT-qPCR (88.9% and 90.0%, respectively). The specificities of 31 clinical negative samples were 92.3% and 91.7% for the N gene and the orf1ab gene, respectively. The limits of detection (LoD) of the clinical samples were 28.3 copies/mL and 23.3 copies/mL for the N gene and the orf1ab gene, respectively. The efficient NanoPEIA detection strategy facilitates real-time detection and visualization within ultrashort durations and can be applied for POCT diagnosis in resource-poor and highly populated areas.

Real-Time Reverse Transcription Recombinase-Aided Amplification Assay for Rapid Amplification of the N Gene of SARS-CoV-2.

COVID-19 was officially declared a global pandemic disease on 11 March 2020, with severe implications for healthcare systems, economic activity, and human life worldwide. Fast and sensitive amplification of the severe acute respiratory syndrome virus 2 (SARS-CoV-2) nucleic acids is critical for controlling the spread of this disease. Here, a real-time reverse transcription recombinase-aided amplification (RT-RAA) assay, targeting conserved positions in the nucleocapsid protein gene (N gene) of SARS-CoV-2, was successfully established for SARS-CoV-2. The assay was specific to SARS-CoV-2, and there was no cross-reaction with other important viruses. The sensitivity of the real-time RT-RAA assay was 142 copies per reaction at 95% probability. Furthermore, 100% concordance between the real-time RT-RAA and RT-qPCR assays was achieved after testing 72 clinical specimens. Further linear regression analysis indicated a significant correlation between the real-time RT-RAA and RT-qPCR assays with an R2 value of 0.8149 (p < 0.0001). In addition, the amplicons of the real-time RT-RAA assay could be directly visualized by a portable blue light instrument, making it suitable for the rapid amplification of SARS-CoV-2 in resource-limited settings. Therefore, the real-time RT-RAA method allows the specific, sensitive, simple, rapid, and reliable detection of SARS-CoV-2.

Parapoxvirus-based therapy eliminates SARS-CoV-2-loaded fine aerosol and blocks viral transmission in hamster models.

Currently, it is believed that severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is an airborne virus, and virus-containing aerosol particles have been found concurrent with the onset of COVID-19, which may contribute to the noncontact transmission of SARS-CoV-2. Exploring agents to block SARS-CoV-2 transmission is of great importance to prevent the COVID-19 pandemic. In this study, we found that inactivated Parapoxvirus ovis (iORFV), a kind of immunomodulator, could compress the proportion of small particle aerosols exhaled by Syrian golden hamsters. Notably, the concentration of SARS-CoV-2 RNA-containing aerosol particles was significantly reduced by iORFV in the early stages after viral inoculation. Importantly, smaller aerosol particles (<4.7 µm) that carry infectious viruses were completely cleared by iORFV. Consistently, iORFV treatment completely blocked viral noncontact (aerosol) transmission. In summary, iORFV may become a repurposed agent for the prevention and control of COVID-19 by affecting viral aerosol exhalation and subsequent viral transmission.

Pathogenicity and Transmissibility of Clade 2.3.4.4h H5N6 Avian Influenza Viruses in Mammals.

Avian influenza viruses (AIVs) have the potential for cross-species transmission and pandemics. In recent years, clade 2.3.4.4 H5N6 AIVs are prevalent in domestic poultry, posing a threat to the domestic poultry industry and public health. In this study, two strains of H5N6 AIVs were isolated from chickens in Hebei, China, in 2019: A/chicken/Hebei/HB1907/2019(H5N6) and A/chicken/Hebei/HB1905/2019(H5N6). Phylogenetic analysis showed that both viral HA genes clustered in the 2.3.4.4h clade. Receptor binding analysis showed that the HB1905 strain preferentially binds to α-2,3-linked sialic acid (SA) receptors, while the HB1907 strain preferentially binds to α-2,3- and α-2,6-linked sialic acid (SA) receptors. During early infection, the HB1907 strain is highly replicable in MDCK cells, more so than the HB1905 strain. Pathogenicity assays in mice showed that both viruses could replicate in the lungs without prior adaptation, with HB1907 being more highly pathogenic in mice than the HB1905 strain. Significantly, both the HB1905 and HB1907 strains can be transmitted through direct contact among guinea pigs, but the transmission efficiency of the HB1907 strain through contact between guinea pigs is much greater than that of the HB1905 strain. These results strengthen the need for ongoing surveillance and early warning of H5N6 AIVs in poultry.

Corrigendum: The possible correlation between serum GRB2 levels and carotid atherosclerosis in patients with type 2 diabetes mellitus.

[This corrects the article DOI: 10.3389/fendo.2022.963191.].

Pathogenicity and Transmissibility of Goose-Origin H5N6 Avian Influenza Virus Clade 2.3.4.4h in Mammals.

Throughout the last decade, H5N6 avian influenza viruses (AIVs) circulating in poultry and infecting humans have caused increasing global concerns that they might become a pandemic threat to global health. Since AIVs could occasionally cause asymptomatic infections in geese, virus monitoring in such a host should be critical to the control of cross-species infection. In addition, previous studies showed that clade 2.3.4.4h H5N6 AIVs could infect mammals without adaptation. However, the pathogenicity and transmissibility of goose-origin clade 2.3.4.4h H5N6 AIVs in mammals remain unknown. In this study, two H5N6 AIVs were isolated from a domestic chicken (A/chicken/Hebei CK05/2019 (H5N6)) and a goose (A/goose/Hebei/GD07/2019(H5N6)). This study is the first to evaluate the pathogenicity and transmissibility of goose-origin clade 2.3.4.4h H5N6 AIVs in mammals by comparison with chicken-origin 2.3.4.4h H5N6 AIVs. The CK05 virus had an affinity for α-2,3-receptors, while the GD07 virus had an affinity for both α-2,3-and α-2,6-receptors. The GD07 virus had a higher replication capacity in vitro and more severe pathogenicity in mice than the CK05 virus. The CK05 virus could not be transmitted effectively among guinea pigs, whereas the GD07 virus could be transmitted through direct contact among guinea pigs. The results of this study indicated the potential health threat of clade 2.3.4.4h H5N6 AIVs to mammals and emphasized the importance of continuous monitoring of H5N6 AIVs, especially in waterfowl.