Specific pathogen-free(SPF)chickens are widely used in the research of avian diseases and vaccines.Vertically transmissible diseases are transmitted to chickens through vertical transmission,seriously affecting their survival rate,increasing production costs,and causing significant economic losses to the poultry industry,while severely impacting the breeding and use of SPF chickens.Therefore,it is crucial for researchers and managers to enhance their understanding of vertically transmissible pathogens in chickens and to develop effective monitoring measures.Quality monitoring is an important part of ensuring the quality of SPF chickens,with pathogen detection being the primary step.Based on this,it is necessary to cultivate qualified SPF chickens through purification methods and biosecurity measures.This paper reviews the major vertically transmissible pathogens in chickens,including viral pathogens,bacterial pathogens and mycoplasmas,as well as their detection methods.This study compares the differences in microbiological testing items and methods for SPF chickens between the U.S.corporate standard and the Chinese national standard.Analysis of the results shows that in both standards,vertically transmissible pathogens such as Escherichia coli,Proteus mirabilis,Salmonella,and avian leukosis are not included in the microbiological testing items for SPF chickens.Instead,these pathogens are characterized by mixed infections,and outbreaks can seriously affect flock health.To produce higher-quality SPF chickens,it is necessary to include these pathogens in the mandatory testing items.The aim of this paper is to help readers understand the relevant standards for microbiological monitoring of SPF chickens,the hazards of vertically transmissible pathogens,and prevention and control strategies,so as to provide a reference for the detection and purification of pathogens in SPF chickens.

Objective To compare the clinical outcomes of all-arthroscopic suture bridge fixation and posteromedial approach open reduction and internal fixation with screws for avulsion fractures of the posterior cruciate ligament (PCL) attachment in the knee joint. Methods A retrospective analysis was conducted on the clinical data of 45 patients with avulsion fractures of the PCL attachment in the knee who were admitted to the Orthopedics and Traumatology Joint Ward of Zhangjiagang Traditional Chinese Medicine Hospital of Jiangsu Province between April 2021 and July 2023. The patients were divided into arthroscopic group (undergoing all-arthroscopic suture bridge fixation) and open internal fixation group (undergoing posteromedial approach open reduction and internal fixation with screws) based on varied surgical approach they received. The operative time and length of hospital stay for both groups were recorded, and the Visual Analogue Scale (VAS) scores before surgery, at 1 month and 6 months after surgery were assessed. The International Knee Documentation Committee (IKDC) subjective score, Lysholm knee function score, and Hospital for Special Surgery (HSS) knee function score were used to evaluate knee function before surgery and at 6 months after surgery. At 6 months after surgery, the range of motion of the affected knee joint was recorded, and the posterior drawer test was performed to assess the degree of PCL injury. Results None of 45 patients experienced vascular or nerve injury intraoperatively, and there were no postoperative wound infections. X-ray examinations conducted 3 days after surgery showed good reduction of the fractures. All patients were followed up for 6 months. There were statistically significant differences in operative time, length of hospital stay and VAS scores at 1 month after surgery between the two groups (P < 0.05). However, there were no statistically significant differences in preoperative IKDC scores, Lysholm function scores, HSS knee function scores, range of motion at 6 months after surgery, and HSS scores between the two groups (P>0.05). There were statistically significant differences in IKDC scores and Lysholm function scores between the two groups at 6 months after surgery (P < 0.05). At 6 months after surgery, there were 16 cases with grade I injury and 6 cases of grade II injury in the arthroscopic group, and 15 cases of grade I injury and 8 cases of grade II injury in the open internal fixation group. There was no statistically significant difference in the degree of PCL injury between the two groups (Z=-0.538, P=0.591). Conclusion Both all-arthroscopic suture bridge fixation and posteromedial approach open reduction and internal fixation with screws can achieve satisfactory clinical outcomes in the treatment of avulsion fractures of the PCL attachment. However, arthroscopic surgery has shorter incision and hospital stays, and can relieve early postoperative knee pain, with more pronounced advantages in knee function recovery.

Objective To analyze the changes of postoperative pulmonary function in lung transplant recipients. Methods Clinical data of 81 recipients undergoing bilateral lung transplantation and combined heart-lung transplantation were collected, and postoperative status of the recipients was analyzed. Pulmonary ventilation and diffusion function indexes at 1 month, 3 months, every 3 months (3-18 months after lung transplantation) and every 6 months (18-36 months after lung transplantation) were analyzed in the recipients. The characteristics of the optimal pulmonary function in the recipients were assessed. Results Postoperative mechanical ventilation time was 4 (2, 9) d, and the length of postoperative ICU stay was 10 (7, 20) d. Among 81 recipients, 27 recipients developed primary graft dysfunction (PGD) after lung transplantation, with an incidence rate of 33%. Postoperative forced vital capacity (FVC) to predicted value ratio (FVC%pred), forced expiratory volume in one second (FEV₁) to predicted value ratio (FEV₁%pred), FEV₁/FVC to predicted value ratio (FEV₁/FVC%pred) and corrected diffusion lung capacity for CO to predicted value ratio (D_LCOc%pred) were changed over time (all P<0.001). FVC%pred and FEV₁%pred were gradually increased within postoperative 9 months, and D_LCOc%pred was gradually elevated within postoperative 3 months (all P<0.05). Thirty-six recipients had FVC%pred≥80%, FEV₁%pred≥80% in 41 cases, FEV₁/FVC%pred≥92% in 76 cases, FVC%pred≤40% in 1 case and FEV₁%pred≤40% in 1 case, respectively. Sixteen recipients had D_LCOc%pred≥80%, corrected diffusion lung capacity for CO/alveolar volume to predicted value ratio (D_LCOc/V_A%pred) ≥80% in 63 cases, D_LCOc%pred≤40% in 4 cases and D_LCOc/V_A%pred≤40% in 1 case, respectively. Postoperative FVC%pred, FEV₁/FVC%pred and D_LCOc%pred in recipients with a primary disease of obstructive pulmonary disease were significantly higher than those in their counterparts with restrictive pulmonary disease (all P<0.05). Postoperative D_LCOc%pred in recipients with PGD was significantly lower than that in those without PGD (P<0.05). Conclusions Pulmonary ventilation function in lung transplant recipients reaches the optimal state and maintains a steady state at postoperative 9 months, and pulmonary diffusion function reaches a steady state at postoperative 3 months. Primary diseases and the incidence of PGD may affect postoperative pulmonary function.

Objective To investigate the treatment on de novo donor specific antibody (dnDSA) mediated acute rejection after lung transplantation. Methods Clinical data of 1 recipient with antibody-mediated rejection (AMR) early after lung transplantation was retrospectively analyzed. The process of diagnosis and treatment were assessed. Results The recipient underwent right lung transplantation due to systemic sclerosis-associated end-stage interstitial lung disease. Preoperatively, classⅠ panel reactive antibody (PRA) was positive (11%). No pretreatment was given before transplantation. Antithymocyte globulin induction therapy was delivered on the day of transplantation and postoperatively. The recipient was properly recovered early after transplantation. Chest tightness and shortness of breath occurred at postoperative 13 d, which were progressively worsened and rapidly progressed into type Ⅰ respiratory failure. Class Ⅰ PRA was increased to 58%, and dnDSA was observed at the loci of A24: 02. The mean fluorescence intensity (MFI) was 2 110. According to the guidelines of International Society for Heart and Lung Transplantation, the recipient was diagnosed as possible AMR. After comprehensive treatment including plasmapheresis, protein A immunoadsorption, glucocorticoid pulse, rituximab and immunoglobulin intravenous drip, the PRA and DSA levels were gradually decreased, and the MFI of DSA was 0 at postoperative 20 d. Clinical condition of the recipient was gradually improved. The dyspnea was healed, shortness of breath was eased, respiratory failure was treated, and pulmonary effusion was gradually absorbed. At postoperative 45 d, the recipient was discharged after full recovery. During 1-year follow-up, the recipient was physically stable and obtained normal quality of life. Class Ⅰ PRA was 5%, and class Ⅱ PRA was negative. No DSA was noted. Conclusions Based on traditional drug therapy, supplement of protein A immunoadsorption therapy may effectively eliminate DSA from the circulating blood of the recipient and mitigate the damage of target organs. Ideal short- and long-term prognosis may be achieved. Traditional drug therapy combined with immunoadsorption may yield ideal efficacy in treating AMR after lung transplantation.

Objective:To study the risk factors of intra-abdominal infection after hepatectomy in patients with primary liver neoplasms.Methods:The clinical data of patients with primary liver neoplasms who underwent hepatectomy at the Department of Hepatobiliary Surgery, Mengchao Hepatobiliary Hospital of Fujian Medical University from January 2019 to December 2021 were retrospectively analyzed. Of 1 229 patients who were enrolled, 48 patients developed postoperative abdominal infection. There were 45 males and 3 females, with age of 58.0 (45.0, 66.0) years old in the infected group. Forth-eight patients without postoperative abdominal infection were selected based on the random number formula to be allocated to the uninfected group to include 44 males and 4 females with age of 58.5 (48.5, 64.8) years old. The general data, preoperative and postoperative laboratory test results, types of liver neoplasms and hepatectomy, pathogenic infective microorganisms and their drug sensitivity tests were collected. Univariate analysis was used to analyze the related factors of intra-abdominal infection after hepatectomy, and significant factors were included in logistic multivariate regression analysis.Results:Of 24 pathogenic strains which were detected in the 143 samples of abdominal infection, the positive rate of culture was 16.78%(24/143). Multivariate logistic regression analysis showed that prealbumin <180 mg/L ( OR=3.757, 95% CI: 1.117-12.634), intraoperative blood transfusion ( OR=6.363, 95% CI: 1.301-31.113) and the time of drainage tube placement ≥7 d ( OR=31.098, 95% CI: 6.906~140.029) were independent risk factors of intra-abdominal infection after hepatectomy. Conclusion:Prealbumin <180 mg/L, intraoperative blood transfusion and the time of drainage tube placement ≥7 d were independent risk factors of intra-abdominal infection after hepatectomy for primary liver neoplasms.

Acute cellular rejection (ACR) is a common complication after lung transplantation, which is mainly caused by the immune response of T lymphocytes recognizing the major histocompatibility complex on the cellular surface of grafts. It is currently considered as the main pattern of acute rejection. ACR is not only a direct cause of death of recipients, but also a high-risk factor for chronic rejection after lung transplantation. Nevertheless, it is a challenging task to deliver the diagnosis and treatment of ACR following lung transplantation. In this article, new progresses on the risk factors, pathogenesis, diagnosis and treatment of ACR in lung transplant recipients were summarized, aiming to improve the diagnostic and treatment efficiency of ACR and prolong the survival of recipients.

Domestic and foreign literatures related to the persistence of SARS-CoV-2 and the re-positive cases infected with SARS-CoV-2 were reviewed, and the characteristics and infectivity of the re-positive cases were analyzed to provide scientific evidence for the improvement of case management and the development of measures to stop the spread of SARS-CoV-2. Existing studies have shown that re-positive rate of SARS-CoV-2 ranged from 2.4% to 19.8%, the median of interval between re-positive detection and discharge was 4-15 days. Following the second course of the disease, the anti-SARS-CoV-2 IgM, IgG and IgA positive rates of the cases were 11.11%-86.08%, 52.00%-100.00% and 61.54%-100.00% respectively, the total antibody and neutralizing antibody positive rates were 98.72% and 88.46%. The viral load of the re-positive cases was lower than that in the initial infection. At least 3 380 re-positive cases have been reported globally. SARS-CoV-2 strains were isolated from the samples of 3 re-positive cases (1 immunodeficiency case and 2 cases with abnormal pulmonary imaging). There were close contacts that were infected by an asymptomatic case taking immunosuppressive agents. In conclusion, the infectivity of re-positive cases infected with SARS-CoV-2 is generally very low. Rare re-positive cases infected with SARS-CoV-2 might cause further transmission. The management approach for the re-positive cases can be based on the assessment of the individual transmission risk according to the pathogen detection results.
Antibodies, Neutralizing ; Antibodies, Viral ; COVID-19 ; Humans ; Immunoglobulin M ; SARS-CoV-2

COVID-19 is an emerging infectious disease caused by SARS-CoV-2. After the infection of the virus, the host immune system is stimulated to produce multifarious specific antibodies to decrease or eliminate effects of the pathogen. Study of the specific antibodies dynamic characteristics in patients with COVID-19 is very important for the understanding and diagnosis of the disease, research and development of vaccine, and planning of prevention and control strategy. This paper reviews and summarizes the domestic and oversea research on dynamic characteristics of specific antibodies of COVID-19 patients, including the antibody producing, duration and level, and its possible influencing factors in order to improve the understanding of the immunological characteristics of COVID-19.

The studies on infectiousness of person infected with SARS-CoV-2 at different stages of illness are an important basis for making effective prevention and control measures such as investigating the infectious source, determining the scope of close contacts and the timing of case isolation. This review discusses the infectiousness of cases infected with SARS-CoV-2 in the incubation period, symptomatic period and convalescent period by reviewing national and international literatures, technical and professional guidelines. Existing researches suggest that the infectious viruses could be isolated at the end of the incubation period as well as since illness onset, and viral load in upper respiratory tract swabs reached the peak on day 4-6 after illness onset and thereafter began to decline, implying the infectiousness was relatively strong at the end of incubation period and within one week after illness onset. Although there were a few cases who tested positive for SARS-CoV-2 after recovery, no evidence was found to indicate these cases can cause the transmission.

Objective:To analyze the incidence of acute respiratory infection (ARI) and related healthcare seeking behaviors in population in the period of COVID-19 epidemic in China.Methods:According to the province specific cumulative incidence rates of COVID-19 reported as of March 31, 2020, the low, medium and high-risk areas were classified. In these areas, a stratified two stage cluster random sampling method was used to select participants for face-to-face questionnaire surveys. Data on the incidence of ARI and related healthcare seeking behaviors in community residents during COVID-19 epidemic period were collected to calculate the attack rate of ARI and related healthcare seeking rate. Logistic regression method was used to explore the influencing factors for ARI incidence and healthcare seeking behavior.Results:A total of 34 857 community residents were surveyed, in whom 647 (1.9%) reported that they had ARI symptoms during the COVID-19 epidemic period, and 241 (37.2%) had healthcare seeking behaviors. In terms of the incidence of COVID-19-related ARI, in high-risk area, the risk of COVID-19-related ARI was 1.36 times (95% CI: 1.12-1.65) than that in low-risk area; among different age groups, the risk of COVID-19-related ARI in age groups 20-39 years, ≥60 years was 1.80 times (95% CI: 1.29-2.59) and 1.63 times (95% CI: 1.14-2.40) than that in age group 1-9 years; the risk of COVID-19-related ARI in people with underlying diseases was 1.53 times (95% CI: 1.23-1.89) than that in those without underlying diseases; the risk of COVID-19-related ARI in people with contacts with confirmed cases of COVID-19 and people with fever or respiratory symptoms was 1.53 times (95% CI: 1.01-2.27) and 6.60 times (95% CI: 5.05-8.53) than those in people without these contacts. The healthcare seeking rate in COVID-19-related ARI patients with exposures to those with fever or respiratory symptoms was 1.68 times (95% CI: 1.05-2.70) than that in such patients without the exposures. Conclusions:The attack rate of COVID-19-related ARI was affected by the local epidemic level of COVID-19, and in high-risk area, the attack rate of COVID-19-related ARI was also high. The healthcare seeking rate in patients with COVID-19-related ARI was low. Therefore, it is necessary to encourage the healthcare seeking in people with ARI in COVID-19 pandemic period.