We found that the overall second infection rate of SARS-COV-2 was 32.4% within household. The estimated median incubation period and serial interval were 4.3 days and 5.1 days, respectively. Early isolation of patients and contact investigation should be initiated urgently. AbstractBackground: To illustrate the extent of transmission, identify affecting risk factors and estimate epidemiological modeling parameters of SARS-CoV-2 in household setting. Methods:We enrolled 35 confirmed index cases and their 148 household contacts, January 2020-February 2020, in Zhuhai, China. All participants were interviewed and asked to complete questionnaires. Household contacts were then prospectively followed active symptom monitoring through the 21-day period and nasopharyngeal and/or oropharyngeal swabs were collected at 3-7 days intervals. Epidemiological, demographic and clinical data (when available) were collected. Results:Assuming that all these secondary cases were infected by their index cases, the second infection rate (SIR) in household context is 32.4% (95% confidence interval [CI] 22.4%-44.4%), with 10.4% of secondary cases being asymptomatic. Multivariate analysis showed that household contacts with underlying medical conditions, a history of direct exposure to Wuhan and its surrounding areas, and shared vehicle with an index patient were associated with higher susceptibility. Household members without protective measures after illness onset of the index patient seem to increase the risk for SARS-CoV-2 infection. The median incubation period and serial interval within household were estimated to be 4.3 days (95% CI; 3.4 to 5.3 days) and 5.1 days (95% CI; 4.3 to 6.2 days), respectively. Conclusion:Early isolation of patients with COVID-19 and prioritizing rapid contact investigation, followed by active symptom monitoring and periodic laboratory evaluation, should be initiated immediately after confirming patients to address the underlying determinants driving the continuing pandemic.

Tropheryma whipplei is the bacterium associated with Whipple’s disease (WD), a chronic systemic infectious disease primarily involving the gastrointestinal tract. T. whipplei can also be detected in different body site of healthy individuals, including saliva and feces. Traditionally, Tropheryma whipplei has a higher prevalence in bronchoalveolar lavage fluid (BALF) of immunocompromised individuals. Few studies have explored the significance of the detection of T. whipplei in BALF. Herein, we retrospectively reviewed 1725 BALF samples which detected for metagenomic next-generation sequencing (mNGS) from March 2019 to April 2022 in Zhuhai, China. Seventy BALs (70/1725, 4.0%) from 70 patients were positive for T. whipplei. Forty-four patients were male with an average age of 50 years. The main symptoms included cough (23/70), expectoration (13/70), weight loss (9/70), and/or dyspnea (8/70), but gastrointestinal symptoms were rare. Chronic liver diseases were the most common comorbidity (n=15, 21.4%), followed by diabetes mellitus (n=13, 18.6%). Only nine patients (12.9%) were immunocompromised. Twenty-four patients (34.3%) were finally diagnosed with reactivation tuberculosis and 15 patients (21.4%) were diagnosed with lung tumors, including 13 primary lung adenocarcinoma and two lung metastases. Fifteen patients (21.4%) had pneumonia. Among the 20 samples, T. whipplei was the sole agent, and Mycobacterium tuberculosis complex was the most common detected other pathogens. Among the non-tuberculosis patients, 31 (31/46, 67.4%) had ground glass nodules or solid nodules on chest CT. Our study indicates that T. whipplei should be considered as a potential contributing factor in some lung diseases. For non-immunocompromised patients, the detection of T. whipplei also needs attention. The mNGS technology improves the detection and attention of rare pathogens. In the future, the infection, colonization, and prognosis of T. whipplei in lung still need to be studied.

BackgroundImpulse oscillometry (IOS) can be used to evaluate airway impedance in patients with obstructive airway diseases. Previous studies have demonstrated that IOS parameters differ between patients with bronchiectasis and healthy controls. This study aims to explore the usefulness of IOS in assessing disease severity and airway reversibility in patients with bronchiectasis.MethodSeventy-four patients with non-cystic fibrosis bronchiectasis who visited our Respiratory Medicine outpatient clinic were consecutively recruited. Spirometry, plethysmography and IOS tests were performed. Patients were stratified into mild, moderate and severe disease according to Reiff, Bhalla, BSI, FACED, and BRICS scores. Airway reversibility was measured by bronchodilation test (BDT) and the result was classified as positive or negative. ROC curves of IOS parameters were used to assess the usefulness of IOS parameters in predicting airway reversibility. Correlations between the IOS, spirometric lung function and bronchiectasis severity parameters were analyzed.ResultsMany IOS parameters, such as airway resistance at 5 Hz (R5), small airways resistance (R5–R20), total airway reactance (X5), resonance frequency (Fres), total airway impedance at 5 Hz (Z5), and peripheral resistance (Rp) increased in patients with bronchiectasis who presented a moderate to severe severity as categorized by the FACED, BSI and Reiff scores. Large airway resistance (R20) and central resistance (Rc) were not significantly different among groups with different bronchiectasis severity. The difference between R5 and R20 (R5-R20) showed 81.0% sensitivity, and 69.8%specificity in predicting the airway reversibility in bronchiectasis with AUC of 0.794 (95%CI, 0.672–0.915).ConclusionIOS measurements are useful indicators of bronchiectasis severity and may be useful for predicting the airway reversibility.

Background: Asthma is a serious global health problem, severely affecting the lives of sufferers and their families. An exceptionally hygienic home and reduced microbial exposure can aggravate the incidence of childhood asthma. Methods: Specific-pathogen-free BALB/c mice were pre-treated with bacterial lysate (BL; 1 mg/kg) as a high microbial load maternal mouse model, and then, the offspring mice were established as an allergic airway disease (AAD) model. The expression levels of TLR2, TLR4, and HDAC9 in the mother's intestine and the offspring's lungs were detected. Relevant indicators of regulatory T cells (Tregs) were identified in the mother and offspring mice. The changes in the expression of Th1-, Th2-, Th9-, and Th17-related cytokines in the offspring mice were evaluated among different pretreated groups. Results: After augmenting the mothers' intestinal microbiota through oral BL gavage, the expression of TLR2 and TLR4 in the colon mucosa and colon lymphoid tissues was enhanced and that of HDAC9 in the colon mucosa was decreased, and the proportion of spleen Tregs was increased. The offspring showed similar changes in the AAD model compared with the offspring of the control-group mothers: TLR2 and TLR4 expression in the lungs and the proportion of spleen Tregs increased, HDAC9 expression in the lungs decreased, and AAD-induced airway pathologic characteristics were reversed; additionally, Th1/Th2 and Th9 imbalances were rectified. Conclusions: This study presents a new framework for the prevention of childhood asthma, elucidating the mechanism of regulating the mother's intestinal microbiome to protect the offspring's early asthma via animal experiments.

Background: Few studies have explored the correlation between asthma medication and features on HRCT images. We aim to analyse the differences and temporal changes of lung function and airway resistance in asthma with diverse HRCT phenotypes in a short period after inhalation of budesonide/formoterol. Method: This observational study recruited 55 adult patients with varying severities of asthma. We performed detailed airway metrics measurements of chest CT scans, such as airway wall thickness (WT), wall area percentage (WA%), wall thickness percentage (T/OR), and airways with an inner perimeter of 10 mm (Pi10). The effect of lung structural features on asthma medication response was explored according to the WA% and T/OR twelve hours post-drug administration. Using multivariable regression models, we then assessed the influence of WA% on lung function. Results: WA% (p < 0.001) and T/OR (p < 0.001) significantly increased in asthma than in healthy control subjects. Compared to mild asthma, airway walls were further thickened (WA%, p = 0.023; T/OR: p = 0.029) and associated with lumen narrowing (Pi10, p = 0.055) in moderate to severe asthma. WA% and T/OR correlated well with lung function (FEV1, FVC, MMEF, and PEF) and airway resistance (R5, R20, Rp, and Fres). Regression analysis showed that MEF25 decreased with increasing age and WA% (R2 = 0.58, p < 0.001). Patients with thickened airway walls experienced a maximal increase in FVC, FEV1, and PEF at 2 h (p < 0.001) and a maximal decrease of R5, Z5, and Rp at 2 h (p < 0.001) in those with a thickened airway pattern. Conclusions: Asthma patients with different bronchial wall thicknesses exhibited variable lung function changes. Specifically, patients with thick airway wall patterns were more sensitive to inhaled budesonide in the short term.