[The effect of on-demand glucocorticoid strategy on the occurrence and outcome of p-ALG-associated serum sickness in aplastic anemia]

Objective: To investigate the effect of on-demand glucocorticoid strategy on the occurrence and outcome of porcine anti-lymphocyte globulin (p-ALG) -associated serum sickness in aplastic anemia (AA) . Methods: The data of AA patients who received in the Anemia Diagnosis and Treatment Center of Haematology Hospital, CAMS & PUMC from January 2019 to January 2022 were collected. Among them, 35 patients were enrolled in the on-demand group, with the glucocorticoid strategy adjusted based on the occurrence and severity of serum sickness; 105 patients were recruited in the usual group by matching the age and disease diagnosis according to 1∶3 ratio in patients who received a conventional glucocorticoid strategy in the same period. The incidences, clinical manifestations, treatment outcomes of serum sickness, and glucocorticoid dosage between the two groups were analyzed. Results: The incidences of serum sickness in the on-demand group and the usual group were 65.7% and 54.3% (P=0.237) , respectively. The median onset of serum sickness was the same [12 (9, 13) d vs the 12 (10, 13) d, P=0.552], and clinical symptoms and signs, primarily joint, and/or muscle pain, fever, and rash were similar. Severity grades were both dominated by Grades 1-2 (62.8% vs 51.4%) , with only a few Grade 3 (2.9% vs 2.9%) , and no Grades 4-5. No significant difference in the serum sickness distribution (P=0.530) . The median duration of serum sickness was the same [5 (3, 7) d vs 5 (3, 6) d, P=0.529], and all patients were completely cured after glucocorticoid therapy. In patients without serum sickness, the average dosage of prophylactic glucocorticoid per patient in the usual group was (469.48 ±193.57) mg (0 in the on-demand group) . When compared to the usual group, the average therapeutic glucocorticoid dosage per patient in the on-demand group was significantly lower [ (125.91±77.70) mg vs (653.90±285.56) mg, P<0.001]. Conclusions: In comparison to the usual glucocorticoid strategy, the on-demand treatment strategy could significantly reduce glucocorticoid dosage without increasing the incidence of serum sickness; in addition, the duration of serum sickness and the incidence of above Grade 2-serum sickness were similar.

[Metagenomic next-generation sequencing of plasma for the identification of bloodstream infectious pathogens in severe aplastic anemia]

Objective: To analyze the diagnostic value of cell-free plasma metagenomic next-generation sequencing (mNGS) pathogen identification for severe aplastic anemia (SAA) bloodstream infection. Methods: From February 2021 to February 2022, mNGS and conventional detection methods (blood culture, etc.) were used to detect 33 samples from 29 consecutive AA patients admitted to the Anemia Diagnosis and Treatment Center of the Hematology Hospital of the Chinese Academy of Medical Sciences to assess the diagnostic consistency of mNGS and conventional detection, as well as the impact on clinical treatment benefits and clinical accuracy. Results: ①Among the 33 samples evaluated by mNGS and conventional detection methods, 25 cases (75.76%) carried potential pathogenic microorganisms. A total of 72 pathogenic microorganisms were identified from all cases, of which 65 (90.28%) were detected only by mNGS. ②All 33 cases were evaluated for diagnostic consistency, of which 2 cases (6.06%) were Composite, 18 cases (54.55%) were mNGS only, 2 cases (6.06%) were Conventional method only, 1 case (3.03%) was both common compliances (mNGS/Conventional testing) , and 10 cases (30.3%) were completely non-conforming (None) . ③All 33 cases were evaluated for clinical treatment benefit. Among them, 8 cases (24.24%) received Initiation of targeted treatment, 1 case (3.03%) received Treatment de-escalation, 13 cases (39.39%) received Confirmation, and the remaining 11 cases (33.33%) received No clinical benefit. ④ The sensitivity of 80.77%, specificity of 70.00%, positive predictive value of 63.64%, negative predictive value of 84.85%, positive likelihood ratio of 2.692, and negative likelihood ratio of 0.275 distinguished mNGS from conventional detection methods (21/12 vs 5/28, P<0.001) . Conclusion: mNGS can not only contribute to accurately diagnosing bloodstream infection in patients with aplastic anemia, but can also help to guide accurate anti-infection treatment, and the clinical accuracy is high.

A sex- and site-specific relationship between body mass index and osteoarthritis: evidence from observational and genetic analyses

OBJECTIVE

We primarily aimed to investigate whether there are phenotypic and genetic links underlying body mass index (BMI) and overall osteoarthritis (OA). We then intended to explore whether the relationships differ across sexes and sites.

METHOD

We first evaluated the phenotypic association between BMI and overall OA using data from the UK Biobank. We then investigated the genetic relationship leveraging summary statistics of the hitherto largest genome-wide association studies performed for BMI and overall OA. Finally, we repeated all analyses in a sex- (female, male) and site- (knee, hip, spine) specific manner.

RESULTS

Observational analysis suggested an increased hazard of diagnosed OA per 5 kg/m² increment in BMI (hazard ratio = 1.38, 95% confidence interval (CI) = 1.37-1.39). A positive overall genetic correlation was observed for BMI and OA (r_g = 0.43, P = 4.72 × 10^-133), corroborated by 11 significant local signals. Cross-trait meta-analysis identified 34 pleiotropic loci shared between BMI and OA, of which seven were novel. Transcriptome-wide association study revealed 29 shared gene-tissue pairs, targeting nervous, digestive, and exo/endocrine systems. Mendelian randomization demonstrated a robust BMI-OA causal relationship (odds ratio = 1.47, 95% CI = 1.42-1.52). A similar pattern of effects was observed in sex- and site-specific analyses, with BMI affecting OA comparably in both sexes and most strongly in the knee.

CONCLUSION

Our work demonstrates an intrinsic relationship underlying BMI and overall OA, reflected by a pronounced phenotypic association, significant biological pleiotropy, and a putative causal link. Stratified analysis further reveals that the effects are distinct across sites and comparable across sexes.

miR-199-3p suppresses cellular migration and viability and promotes progesterone production in goose ovarian follicles before selection through regulating ITGB8 and other ECM-related genes

1. The extracellular matrix (ECM) constitutes the basal lamina and the area between follicular cells. Remodelling the ECM is believed to be a key event in follicular development, especially during selection, and plays an important role in cell migration, survival, and steroidogenesis. miR-199-3p is differentially expressed in the goose granulosa layer during follicular selection and is reported to play a primary role in inhibiting cell migration and invasion. Nevertheless, the effect of miR-199-3p on ovarian follicles and its role in follicular cellular migration is not understood.2. In this study, qRT-PCR assays revealed that miR-199-3p was differentially expressed in the granulosa layer from goose ovarian follicles before and after follicular selection. Additionally, miR-199-3p overexpression in cultured granulosa cells (GCs) from goose pre-hierarchical follicles significantly suppressed cell viability and migration. It elevated the concentration of progesterone and the expression of key progesterone production genes. Furthermore, miR-199-3p overexpression in the GCs of goose pre-hierarchical follicles inhibited the expression of ECM-related genes (ITGB8, MMP9 and MMP15) yet promoted the expression of another two ECM-related genes (COL4A1 and LAMA1). Finally, dual-fluorescence reporter experiments on 293T cells established the direct targeting of ECM gene ITGB8 by miR-199-3p.3. In conclusion, miR-199-3p may participate in granulosa cell migration, viability, and steroidogenesis in goose ovarian follicles before selection by modulating ITGB8 and other ECM-related genes.

Ultra-low-dose CT lung screening with artificial intelligence iterative reconstruction: evaluation via automatic nodule-detection software

AIM

To test the feasibility of ultra-low-dose (ULD) computed tomography (CT) combined with an artificial intelligence iterative reconstruction (AIIR) algorithm for screening pulmonary nodules using computer-assisted diagnosis (CAD).

MATERIALS AND METHODS

A chest phantom with artificial pulmonary nodules was first scanned using the routine protocol and the ULD protocol (3.28 versus 0.18 mSv) to compare the image quality and to test the acceptability of the ULD CT protocol. Next, 147 lung-screening patients were enrolled prospectively, undergoing an additional ULD CT immediately after their routine CT examination for clinical validation. Images were reconstructed with filtered back-projection (FBP), hybrid iterative reconstruction (HIR), the AIIR, and were imported to the CAD software for preliminary nodule detection. Subjective image quality on the phantom was scored using a five-point scale and compared using the Mann-Whitney U-test. Nodule detection using CAD was evaluated for ULD HIR and AIIR images using the routine dose image as reference.

RESULTS

Higher image quality was scored for AIIR than for FBP and HIR at ULD (p<0.001). As reported by CAD, 107 patients were presented with more than five nodules on routine dose images and were chosen to represent the challenging cases at an early stage of pulmonary disease. Among such, the performance of nodule detection by CAD on ULD HIR and AIIR images was 75.2% and 92.2% of the routine dose image, respectively.

CONCLUSION

Combined with AIIR, it was feasible to use an ULD CT protocol with 95% dose reduction for CAD-based screening of pulmonary nodules.

Mechanism of Qingre Huoxue Fang treatment on inhibiting angiogenesis of rheumatoid arthritis based on network pharmacology and in vitro experiments

This study aimed to explore the mechanism of Qingre Huoxue Fang (QRHXF) treatment on anti-angiogenesis in rheumatoid arthritis (RA) based on network pharmacology and in vitro experiments. We used the Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform (TCMSP) and Therapeutic Target (TTD) database to extract the active components of QRHXF and potential targets for regulating angiogenesis. First, we used Cytoscape bioinformatics software to construct the network of QRHXF-angiogenesis and screened the potential targets. Then, we performed gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis on the potential core targets. In addition, enzyme-linked immune assay and Western blot were used for in vitro validation and to verify the effects of different concentrations of QRHXF on the expression levels of the vascular endothelial growth factor receptor type 1 (VEGFR-1) and VEGFR-2 cytokines and phosphoinositide 3-kinase (PI3k) and Ak strain transforming (Akt) proteins in human umbilical vein endothelial cells (HUVECs). In results, we screened 179 core QRHXF antiangiogenic targets, including vascular endothelial growth factor (VEGF) cytokines. Enrichment analysis showed that the targets were enriched in 56 core signaling pathways, including PI3k and Akt. In vitro experiments showed that the migration distance and square, adhesion optical density (OD) values, and the number of branch points in tube formation significantly decreased in the QRHXF group compared with the induced group (P<0.01). Notably, the serum levels of VEGFR-1 and VEGFR-2 were lower compared with the induced group (P<0.05 or P<0.01). In addition, the expressions of PI3K and p-Akt proteins were decreased in the middle- and high doses groups (P<0.01). This study's results suggest that the downstream mechanism of QRHXF anti-angiogenesis might inhibit the PI3K-Akt signalling pathway and downregulate VEGF-1 and VEGF-2.

Mechanism of Qingre Huoxue Fang treatment on inhibiting angiogenesis of rheumatoid arthritis based on network pharmacology and in vitro experiments

This study aimed to explore the mechanism of Qingre Huoxue Fang (QRHXF) treatment on anti-angiogenesis in rheumatoid arthritis (RA) based on network pharmacology and in vitro experiments. We used the Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform (TCMSP) and Therapeutic Target (TTD) database to extract the active components of QRHXF and potential targets for regulating angiogenesis. First, we used Cytoscape bioinformatics software to construct the network of QRHXF-angiogenesis and screened the potential targets. Then, we performed gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis on the potential core targets. In addition, enzyme-linked immune assay and Western blot were used for in vitro validation and to verify the effects of different concentrations of QRHXF on the expression levels of the vascular endothelial growth factor receptor type 1 (VEGFR-1) and VEGFR-2 cytokines and phosphoinositide 3-kinase (PI3k) and Ak strain transforming (Akt) proteins in human umbilical vein endothelial cells (HUVECs). In results, we screened 179 core QRHXF antiangiogenic targets, including vascular endothelial growth factor (VEGF) cytokines. Enrichment analysis showed that the targets were enriched in 56 core signaling pathways, including PI3k and Akt. In vitro experiments showed that the migration distance and square, adhesion optical density (OD) values, and the number of branch points in tube formation significantly decreased in the QRHXF group compared with the induced group (P<0.01). Notably, the serum levels of VEGFR-1 and VEGFR-2 were lower compared with the induced group (P<0.05 or P<0.01). In addition, the expressions of PI3K and p-Akt proteins were decreased in the middle- and high doses groups (P<0.01). This study's results suggest that the downstream mechanism of QRHXF anti-angiogenesis might inhibit the PI3K-Akt signalling pathway and downregulate VEGF-1 and VEGF-2.

[The timing of pericardial drainage catheter removal and restart of the anticoagulation in patients suffered from perioperative pericardial tamponade during atrial fibrillation catheter ablation and uninterrupted dabigatran: Experiences from 20 cases]

Objective: To investigate the timing of pericardial drainage catheter removal and restart of the anticoagulation in patients with atrial fibrillation (AF) suffered from perioperative pericardial tamponade during atrial fibrillation catheter ablation and uninterrupted dabigatran. Methods: A total of 20 patients with pericardial tamponade, who underwent AF catheter ablation with uninterrupted dabigatran in Beijing Anzhen Hospital from January 2019 to August 2021, were included in this retrospective analysis. The clinical characteristics of enrolled patients, information of catheter ablation procedures, pericardial tamponade management, perioperative complications, the timing of pericardial drainage catheter removal and restart of anticoagulation were analyzed. Results: All patients underwent pericardiocentesis and pericardial effusion drainage was successful in all patients. The average drainage volume was (427.8±527.4) ml. Seven cases were treated with idarucizumab, of which 1 patient received surgical repair. The average timing of pericardial drainage catheter removal and restart of anticoagulation in 19 patients without surgical repair was (1.4±0.7) and (0.8±0.4) days, respectively. No new bleeding, embolism and death were reported during hospitalization and within 30 days following hospital discharge. Time of removal of pericardial drainage catheter, restart of anticoagulation and hospital stay were similar between patients treated with idarucizumab or not. Conclusion: It is safe and reasonable to remove pericardial drainage catheter and restart anticoagulation as soon as possible during catheter ablation of atrial fibrillation with uninterrupted dabigatran independent of the idarucizumab use or not in case of confirmed hemostasis.

Metasurface-enhanced mid-infrared spectrochemical imaging of tissues

Label-free and nondestructive mid-infrared vibrational hyperspectral imaging is emerging as an important ex-vivo tissue analysis tool, providing spatially resolved biochemical information critical to understanding physiological and pathological processes. However, the chemically complex and spatially heterogeneous composition of tissue specimens and the inherently weak interaction of infrared light with biomolecules limit the analytical performance of infrared absorption spectroscopy. Here, we introduce an advanced mid-infrared spectrochemical tissue imaging modality using metasurfaces that support strong surface-localized electromagnetic fields to capture quantitative molecular maps of large-area murine brain-tissue sections. Our approach leverages polarization-multiplexed multi-resonance plasmonic metasurfaces to simultaneously detect many different functional biomolecules. The resulting surface-enhanced mid-infrared spectral imaging (SE-MIRSI) method eliminates the non-specific effects of bulk tissue morphology on the quantitative analysis of fingerprint spectra and improves the chemical selectivity. We show that the metasurface enhancement increases the retrieval of amide I and II absorption bands associated with secondary structures of proteins. Moreover, we demonstrate that plasmonic metasurfaces enhance the chemical contrast in infrared images and enable the detection of ultrathin tissue regions that are not otherwise visible to conventional mid-infrared spectral imaging. While we tested our approach on murine brain tissue sections, this chemical imaging method is well-suited for any tissue type, which significantly broadens the potential impacts of our method for both translational research and clinical histopathology.

Tuberculosis complicated by spinal cord cryptococcosis: a case report and literature review

BACKGROUND

Spinal cord involvement by Cryptococcus neoformans infection is extremely rare, with most cases occurring in immunosuppressed patients.

CASE PRESENTATION

A young male patient presented with a 10-day history of progressive lower limb weakness culminating in paralysis, urinary incontinence, and constipation. The patient had no known immunodeficiency induced by the human immunodeficiency virus (HIV), malignancy, or organ transplantation. Laboratory investigations showed elevated C-reactive protein (CRP) levels; however, all other immune indicators were normal. Magnetic resonance imaging (MRI) revealed oval-shaped extradural masses (1.3-3.5 cm) with isointense T1-weighted signal and heterogeneous T2-weighted signal in the spinal canal at the level of the 9th thoracic vertebra. The lesions spread along the intervertebral foramen and involved both sides, showing significant enhancement in contrast-enhanced MRI. The patient was managed surgically, in combination with antifungal and anti-tuberculous therapy and could walk independently 3 months after the treatment. Cryptococcosis was confirmed by histopathology and fungal culture.

CONCLUSIONS

The results suggest that for lesions that affect spinal stability or cause severe nerve damage, surgical treatment should be considered along with medical management.

Muscle Fat Content Is Associated with Nonalcoholic Fatty Liver Disease and Liver Fibrosis in Chinese Adults

OBJECTIVES

Several studies have linked myosteatosis with nonalcoholic fatty liver disease (NAFLD) in individuals with obesity. The clinical significance of myosteatosis in individuals with NAFLD in the general population has not been well investigated. Here, we wanted to explore and compare the associations of NAFLD and liver fibrosis with muscle fat content and skeletal muscle mass (SMM) in a relatively large general population in China.

METHODS

We retrospectively included all participants who underwent abdominal CT scans in our health promotion center between April 2021 and October 2021. Muscle fat content was assessed by abdomen quantitative computed tomography (QCT) scans, and SMM was evaluated by bioelectrical impedance. NAFLD was assessed by ultrasonography. The NAFLD fibrosis score (NFS) and Fibrosis-4 Index (FIB-4) score were calculated to assess liver fibrosis.

RESULTS

Compared with participants without NAFLD, patients with NAFLD showed significantly increased intermuscular adipose tissue (IMAT%) (7.40±3.37% vs. 6.76±2.66%, P <0.01). According to a multiple logistic regression model, IMAT% (OR=1.091, 95% CI 1.030-1.155, P=0.003) was only independently correlated with NAFLD in obese participants. Mediation analysis showed that BMI mediated the association between IMAT% and NAFLD. In participants with NAFLD, increased IMAT% was independently associated with an increased intermediate to high risk of advanced fibrosis assessed by the NFS or FIB-4 score after adjusting for multiple potential confounders. However, SMM was only independently correlated with an intermediate to high risk for advanced fibrosis evaluated by the NFS and not by the FIB-4 score.

CONCLUSION

Increased muscle fat content is positively correlated with NAFLD and intermediate to high risk for advanced fibrosis in the general Chinese population.

[A deep-learning model for the assessment of coronary heart disease and related risk factors via the evaluation of retinal fundus photographs]

Objective: To develop and validate a deep learning model based on fundus photos for the identification of coronary heart disease (CHD) and associated risk factors. Methods: Subjects aged>18 years with complete clinical examination data from 149 hospitals and medical examination centers in China were included in this retrospective study. Two radiologists, who were not aware of the study design, independently evaluated the coronary angiography images of each subject to make CHD diagnosis. A deep learning model using convolutional neural networks (CNN) was used to label the fundus images according to the presence or absence of CHD, and the model was proportionally divided into training and test sets for model training. The prediction performance of the model was evaluated in the test set using monocular and binocular fundus images respectively. Prediction efficacy of the algorithm for cardiovascular risk factors (e.g., age, systolic blood pressure, gender) and coronary events were evaluated by regression analysis using the area under the receiver operating characteristic curve (AUC) and R² correlation coefficient. Results: The study retrospectively collected 51 765 fundus images from 25 222 subjects, including 10 255 patients with CHD, and there were 14 419 male subjects in this cohort. Of these, 46 603 fundus images from 22 701 subjects were included in the training set and 5 162 fundus images from 2 521 subjects were included in the test set. In the test set, the deep learning model could accurately predict patients' age with an R² value of 0.931 (95%CI 0.929-0.933) for monocular photos and 0.938 (95%CI 0.936-0.940) for binocular photos. The AUC values for sex identification from single eye and binocular retinal fundus images were 0.983 (95%CI 0.982-0.984) and 0.988 (95%CI 0.987-0.989), respectively. The AUC value of the model was 0.876 (95%CI 0.874-0.877) with either monocular fundus photographs and AUC value was 0.885 (95%CI 0.884-0.888) with binocular fundus photographs to predict CHD, the sensitivity of the model was 0.894 and specificity was 0.755 with accuracy of 0.714 using binocular fundus photographs for the prediction of CHD. Conclusion: The deep learning model based on fundus photographs performs well in identifying coronary heart disease and assessing related risk factors such as age and sex.

Genetic influences of the effect of circulating inflammatory cytokines on osteoarthritis in humans

OBJECTIVE

The causal relationship between inflammatory cytokines and Osteoarthritis (OA) has not been well investigated. This study investigated the causal role of inflammatory cytokines in the risk of OA and total joint arthroplasty using the Mendelian randomization (MR) method.

METHOD

Single nucleotide polymorphisms (SNPs) robustly associated with inflammatory cytokines were used as instrumental variables. The inverse-variance weighted (IVW) method with false discovery rate (FDR) adjusted P-value (q-value) for multiple comparisons were used as the main MR method to estimate causal effects based on the summary-level data for OA (knee and hip OA, respectively) and total joint arthroplasty (TJA). Sensitivity analyses validated the robustness of the results and ensured the absence of heterogeneity and horizontal pleiotropy.

RESULTS

After FDR adjustment, macrophage colony-stimulating factor (MCSF) and vascular endothelial growth factor (VEGF) were identified as causally associated with knee OA (MCSF, odds ratio [OR]: 1.16, 95% confidence interval [CI]: 1.09-1.23, q = 5.05 × 10^-5; VEGF, OR: 1.09, 95% CI: 1.04-1.15, q = 0.011). We also observed that genetically predicted MCSF and VEGF were positively associated with the risk of TJA, and MCP3 was negatively associated with for the risk of TJA, although the effects seem fairly modest. Sensitivity analysis further excluded the influence of heterogeneity and horizontal pleiotropy.

CONCLUSIONS

Inflammatory cytokines, namely MCSF and VEGF, were causally associated with knee OA, which could enhance our understanding of inflammation in OA pathology.

Genome-wide association study for reproduction-related traits in Chinese domestic goose

1. This study measured six reproduction traits in a Sichuan white goose population (209 individuals), including fertility, qualified egg rate, plasma concentrations of progesterone (P), follicle-stimulating hormone (FSH), prolactin (PRL) and oestrogen (E2).2. Whole-genome resequencing data from the same goose population (209 individuals) were used in a genome-wide association study (GWAS) utilising a mixed linear model to investigate the genes and genetic markers associated with reproduction traits. The frequency of the selected SNPs and haplotypes were determined using the Matrix-Assisted Laser Desorption Ionisation Time-Of-Flight Mass Spectrometry (MALDI-TOF MS) method.3. In total, 42 SNPs significantly associated with these traits were identified. A haplotype block was constructed based on five SNPs that were significantly associated with qualified egg rate, with individuals having the haplotype CCTTAAGGAA having the lowest qualified egg rate.4. In conclusion, these results provided potential markers for marker-assisted selection to improve goose reproductive performance and a basis for elucidating the genetics of goose reproduction.

[Distribution and gene characteristics of H3, H4 and H6 subtypes of low pathogenic avian influenza viruses in environment related avian influenza viruses during 2014-2021 in China]

Objective: To analyze the characteristics of low pathogenic H3, H4 and H6 subtypes of avian influenza viruses in environment related avian influenza viruses in China from 2014 to 2021. Methods: Surveillance sites were located in 31 provinces, autonomous region and municipalities to collect environmental samples related to avian influenza, detect the nucleic acid detection of influenza A virus, isolate virus, deeply sequence, analyze pathogenicity related molecular sites, and determine the distribution and variation characteristics of common H3, H4 and H6 subtypes of avian influenza virus in different regions, places and sample types. Results: A total of 388 645 samples were collected. The positive rate of low pathogenic H3 (0.56‰) and H6 (0.53‰) was higher than that of H4 (0.09‰). The positive rate of H4 subtype virus in live poultry market was higher than that in other places, and the difference was statistically significant. The positive rate of H3 and H6 subtypes in sewage samples was higher than that in other samples, and the difference was statistically significant. The positive rate of H3, H4 and H6 viruses in the south was higher than that in the north, and the difference was statistically significant. December was the most active time for virus. The analysis of pathogenicity related molecular sites showed that H3, H4 and H6 subtypes of viruses combined with avian influenza virus receptors, and some gene sites related to increased pathogenicity had mutations. Conclusion: The H3, H4 and H6 subtypes of low pathogenic avian influenza viruses have a high isolation positive rate in the live poultry market and sewage. The distribution of the three subtypes of viruses has obvious regional and seasonal characteristics, and the genetic characteristics still show the feature of low pathogenic avian influenza.