Dynamic Classification of Plasmodium vivax Malaria Recurrence: An Application of Classifying Unknown Cause of Failure in Competing Risks

A standard competing risks set-up requires both time to event and cause of failure to be fully observable for all subjects. However, in application, the cause of failure may not always be observable, thus impeding the risk assessment. In some extreme cases, none of the causes of failure is observable. In the case of a recurrent episode of Plasmodium vivax malaria following treatment, the patient may have suffered a relapse from a previous infection or acquired a new infection from a mosquito bite. In this case, the time to relapse cannot be modeled when a competing risk, a new infection, is present. The efficacy of a treatment for preventing relapse from a previous infection may be underestimated when the true cause of infection cannot be classified. In this paper, we developed a novel method for classifying the latent cause of failure under a competing risks set-up, which uses not only time to event information but also transition likelihoods between covariates at the baseline and at the time of event occurrence. Our classifier shows superior performance under various scenarios in simulation experiments. The method was applied to Plasmodium vivax infection data to classify recurrent infections of malaria.

[Exploring and bioinformatics analysis of differentially expressed genes in bronchial asthma]

Objective: To screen core differentially expressed genes of bronchial asthma and conduct bioinformatics analysis. Methods: Macrophage microarray data GSE22528 from asthma patients were downloaded from gene expression database (GEO). The dataset included transcriptome information from 10 human alveolar lavage fluid samples, and five of them were from allergic asthmatic subjects and five from control subjects. Differential expression genes (DEGs) were screened by R 4.0.4 software. Gene ontology (GO) function and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis were performed to select DEGs using DAVID 6.8 database. Protein interaction network (PPI) was constructed from DEGs encoded proteins using STRING online database. Cytoscape software was used to construct core modules and determine core DEGs. Results: Alveolar lavage fluid samples were all collected from Caucasian Canadians, with age range as (20, 37) and (18, 36) years, respectively, including 3 males for each group. In asthmatic patients, 449 genes were up-regulated and 47 down-regulated. GO analysis showed that the up-regulated genes in asthmatic patients were mainly involved in biological processes such as response to folded proteins, and the molecular function was focused on binding of folded proteins and growth factors. Down-regulated genes were mainly involved in biological processes such as histone deacetylation and ubiquitin-mediated protein degradation, and their molecular functions focused on histone deacetylation activity. KEGG pathway enrichment analysis showed that pathways were mainly enriched by up-regulation genes, involving Hippo signaling pathway, hypertrophic cardiomyopathy, estrogen signaling pathway, arrhythmogenic right ventricular cardiomyopathy, basal cell carcinoma, neuro-activated receptor ligand interaction, dilated cardiomyopathy and adhesion and connection signaling pathways. Two core modules were obtained by PPI analysis, and 14 core DEGs were screened out. They were pro-melanin concentrating hormone (PMCH), prepronociceptin (PNOC), Sphingosinol-1-phosphate receptor 2 (S1PR2), Sphingosinol-1-phosphate receptor 5 (S1PR5), CC-type chemokine ligand 21 (CCL21), Kelch-like protein 25 (KLHL25), ubiquitin binding enzyme E2V2 (UBE2V2), F-box protein 17 (FBXO17), taste receptor type 2 member 3 (TAS2R3), somatostatin receptor 2 (SSTR2), metabolic glutamate receptor 2 (GRM2), Lister E3 ubiquitin protein ligase 1 (LTN1), LIM domain specific protein 7 (LMO7) and ring finger protein 19A gene(RNF19A), in which LTN1 and UBE2V2 were down-regulated and the rest were up-regulated. Conclusion: DEGs was found in macrophages of asthmatic and control individuals. PMCH, PNOC, S1PR2, S1PR5 and CCL21 might be the core genes in the pathological process of asthma.

[Human bone marrow mesenchymal stem cells improve steroid resistance of human airway epithelial BEAS-2B cells in vitro]

Objective: To explore the effect of human bone marrow mesenchymal stem cells(MSC) on the steroid resistance of human airway epithelial cells. Methods: Ovalbumin (OVA)/lipopolysaccharide (LPS) were used to construct steroid resistant BEAS-2B cells, which were then co-cultured with MSC. Groups were set as follows: blank group, model group, Glucocorticoid group, MSC group, MSC+Glucocorticoid group (MSC+bud group). The expression of interleukin (IL)-8 in the cell supernatant was detected by enzyme-linked immunosorbent assay (ELISA); the expression of reactive oxygen species (ROS) in the cells was detected by flow cytometry; the expression of glucocorticoid receptor α (GRα) and histone deacetylase 2 (HDAC2) protein in the cell was detected by Western blotting; and the expression of GRα and HDAC2 mRNA was detected by reverse transcription-polymerase chain reaction (RTPCR). Results: The expression level of IL-8 in the MSC group was significantly lower than that in the Glucocorticoid group (31.7±0.7 vs. 49.8±3.6, P<0.01). The expression of ROS in the MSC group was significantly lower than that in the Glucocorticoid group (2754±154 vs.4624±228, P<0.05). The expression level of HDAC2 mRNA in the MSC group was significantly higher than that in the Glucocorticoid group(1.749±0.005 vs. 1.283±0.098, P<0.05). The expression level of GRα mRNA in the MSC group was significantly higher than that in the Glucocorticoid group (1.623±0.079 vs.1.047±0.220, P<0.01). The expression of HDAC2 protein in the MSC group was significantly higher than that in the Glucocorticoid group (1.067±0.100 vs. 0.620±0.083, P<0.01). The expression of GRα protein in the MSC group was significantly higher than that in the Glucocorticoid group (0.834±0.053 vs. 0.579±0.017, P<0.01). ROS was positively correlated with the IL-8 expression (r=0.796, P<0.01) and negatively correlated with the HDAC2 and GRα mRNA expression (r=-0.893 3, P<0.01; r=0.931 4, P<0.01, respectively), as well as the HDAC2 and GRα Protein expression (r=-0.929 5, P<0.01;r=-0.864 3, P<0.01, respectively). Conclusions: Human MSC can improve steroid resistance of airway epithelial cells in an exocrine manner. The mechanism may be related to the down-regulation of ROS and up-regulation of HDAC2, which lead to GRα overexpression. In addition, MSC may improve the steroid resistance by reducing the expression of IL-8.

Assessment of the Field Utility of a Rapid Point-of-Care Test for SARS-CoV-2 Antibodies in a Household Cohort

Point-of-care (POC) tests to detect SARS-CoV-2 antibodies offer quick assessment of serostatus after natural infection or vaccination. We compared the field performance of the BioMedomics COVID-19 IgM/IgG Rapid Antibody Test against an ELISA in 303 participants enrolled in a SARS-CoV-2 household cohort study. The rapid antibody test was easily implemented with consistent interpretation across 14 users in a variety of field settings. Compared with ELISA, detection of seroconversion lagged by 5 to 10 days. However, it retained a sensitivity of 90% (160/177, 95% confidence interval [CI] 85-94%) and specificity of 100% (43/43, 95% CI 92-100%) for those tested 3 to 5 weeks after symptom onset. Sensitivity was diminished among those with asymptomatic infection (74% [14/19], 95% CI 49-91%) and early in infection (45% [29/64], 95% CI 33-58%). When used appropriately, rapid antibody tests offer a convenient way to detect symptomatic infections during convalescence.

Practical strategies for SARS-CoV-2 RT-PCR testing in resource-constrained settings

Alternatives to nasopharyngeal sampling are needed to increase capacity for SARS-CoV-2 testing. Among 275 participants, we piloted the collection of nasal mid-turbinate swabs amenable to self-testing, including polyester flocked swabs as well as 3D-printed plastic lattice swabs, placed into viral transport media or an RNA stabilization agent. Flocked nasal swabs identified 104/121 individuals who were PCR-positive for SARS-CoV-2 by nasopharyngeal sampling (sensitivity 87%, 95% CI 79-92%), missing those with low viral load (<10⁶ viral copies/mL). 3D-printed nasal swabs showed similar sensitivity. When nasal swabs were placed directly into RNA preservative, the mean 1.4 log decrease in viral copies/uL compared to nasopharyngeal samples was reduced to <1 log, even when samples were left at room temperature for up to 7 days. We also evaluated pooling strategies that involved pooling specimens in the lab versus pooling swabs at the point of collection, finding both successfully detected samples with >10⁵ viral copies/mL.

A novel CRISPR-based malaria diagnostic capable of Plasmodium detection, species differentiation, and drug-resistance genotyping

Background

CRISPR-based diagnostics are a new class of highly sensitive and specific assays with multiple applications in infectious disease diagnosis. SHERLOCK, or Specific High-Sensitivity Enzymatic Reporter UnLOCKing, is one such CRISPR-based diagnostic that combines recombinase polymerase pre-amplification, CRISPR-RNA base-pairing, and LwCas13a activity for nucleic acid detection.

Methods

We developed SHERLOCK assays capable of detecting all Plasmodium species known to cause human malaria and species-specific detection of P. vivax and P. falciparum, the species responsible for the majority of malaria cases worldwide. We further tested these assays using a diverse panel of clinical samples from the Democratic Republic of the Congo, Uganda, and Thailand and pools of Anopheles mosquitoes from Thailand. In addition, we developed a prototype SHERLOCK assay capable of detecting the dihydropteroate synthetase (dhps) single nucleotide variant A581G associated with P. falciparum sulfadoxine resistance.

Findings

The suite of Plasmodium assays achieved analytical sensitivities ranging from 2•5-18•8 parasites per reaction when tested against laboratory strain genomic DNA. When compared to real-time PCR, the P. falciparum assay achieved 94% sensitivity and 94% specificity during testing of 123 clinical samples. Compared to amplicon-based deep sequencing, the dhps SHERLOCK assay achieved 73% sensitivity and 100% specificity when applied to a panel of 43 clinical samples, with false-negative calls only at lower parasite densities.

Interpretation

These novel SHERLOCK assays demonstrate the versatility of CRISPR-based diagnostics and their potential as a new generation of molecular tools for malaria diagnosis and surveillance.

Funding

National Institutes of Health (T32GM007092, R21AI148579, K24AI134990, R01AI121558, UL1TR002489, P30CA016086)

High household transmission of SARS-CoV-2 in the United States: living density, viral load, and disproportionate impact on communities of color

Background

Few prospective studies of SARS-CoV-2 transmission within households have been reported from the United States, where COVID-19 cases are the highest in the world and the pandemic has had disproportionate impact on communities of color.

Methods and Findings

This is a prospective observational study. Between April-October 2020, the UNC CO-HOST study enrolled 102 COVID-positive persons and 213 of their household members across the Piedmont region of North Carolina, including 45% who identified as Hispanic/Latinx or non-white. Households were enrolled a median of 6 days from onset of symptoms in the index case. Secondary cases within the household were detected either by PCR of a nasopharyngeal (NP) swab on study day 1 and weekly nasal swabs (days 7, 14, 21) thereafter, or based on seroconversion by day 28. After excluding household contacts exposed at the same time as the index case, the secondary attack rate (SAR) among susceptible household contacts was 60% (106/176, 95% CI 53%-67%). The majority of secondary cases were already infected at study enrollment (73/106), while 33 were observed during study follow-up. Despite the potential for continuous exposure and sequential transmission over time, 93% (84/90, 95% CI 86%-97%) of PCR-positive secondary cases were detected within 14 days of symptom onset in the index case, while 83% were detected within 10 days. Index cases with high NP viral load (>10^6 viral copies/ul) at enrollment were more likely to transmit virus to household contacts during the study (OR 4.9, 95% CI 1.3-18 p=0.02). Furthermore, NP viral load was correlated within families (ICC=0.44, 95% CI 0.26-0.60), meaning persons in the same household were more likely to have similar viral loads, suggesting an inoculum effect. High household living density was associated with a higher risk of secondary household transmission (OR 5.8, 95% CI 1.3-55) for households with >3 persons occupying <6 rooms (SAR=91%, 95% CI 71-98%). Index cases who self-identified as Hispanic/Latinx or non-white were more likely to experience a high living density and transmit virus to a household member, translating into an SAR in minority households of 70%, versus 52% in white households (p=0.05).

Conclusions

SARS-CoV-2 transmits early and often among household members. Risk for spread and subsequent disease is elevated in high-inoculum households with limited living space. Very high infection rates due to household crowding likely contribute to the increased incidence of SARS-CoV-2 infection and morbidity observed among racial and ethnic minorities in the US. Quarantine for 14 days from symptom onset of the first case in the household is appropriate to prevent onward transmission from the household. Ultimately, primary prevention through equitable distribution of effective vaccines is of paramount importance.

Practical strategies for SARS-CoV-2 RT-PCR testing in resource-constrained settings

Background

Standard nasopharyngeal swab testing for SARS-CoV-2 detection by PCR is not always feasible due to limitations in trained personnel, personal protective equipment, swabs, PCR reagents, and access to cold chain and biosafety hoods.

Methods

We piloted the collection of nasal mid-turbinate swabs amenable to self-testing, including both standard polyester flocked swabs as well as 3D printed plastic lattice swabs, placed into either viral transport media or an RNA stabilization agent. Quantitative SARS-CoV-2 viral detection by RT-qPCR was compared to that obtained by nasopharyngeal sampling as the reference standard. Pooling specimens in the lab versus pooling swabs at the point of collection was also evaluated.

Results

Among 275 participants, flocked nasal swabs identified 104/121 individuals who were PCR-positive for SARS-CoV-2 by nasopharyngeal sampling (sensitivity 87%, 95% CI 79-92%), mostly missing those with low viral load (<10^3 viral copies/uL). 3D-printed nasal swabs showed similar sensitivity. When nasal swabs were placed directly into an RNA stabilizer, the mean 1.4 log decrease in viral copies/uL compared to nasopharyngeal samples was reduced to <1 log, even when samples were left at room temperature for up to 7 days. Pooling sample specimens or swabs both successfully detected samples >10² viral copies/uL.

Conclusions

Nasal swabs are likely adequate for clinical diagnosis of acute infections to help expand testing capacity in resource-constrained settings. When collected into an RNA preservative that also inactivates infectious virus, nasal swabs yielded quantitative viral loads approximating those obtained by nasopharyngeal sampling.

Direct Comparison of Standard and Ultrasensitive PCR for the Detection of Plasmodium falciparum from Dried Blood Spots in Bagamoyo, Tanzania

Ultrasensitive PCR used in low-transmission malaria-endemic settings has revealed a much higher burden of asymptomatic infections than that detected by rapid diagnostic tests (RDTs) or standard PCR, but there is limited evidence as to whether this is the case in higher transmission settings. Using dried blood spots (DBS) collected among 319 schoolchildren in Bagamoyo, Tanzania, we found good correlation (Pearson's R = 0.995) between Plasmodium falciparum parasite densities detected by a DNA-based 18s rRNA real-time PCR (qPCR) and an RNA-based ultrasensitive RT-PCR (usPCR) for the same target. Whereas prevalence by usPCR was higher than that found by qPCR (37% versus 32%), the proportion of additionally detected low-density infections (median parasite density < 0.050 parasites/µL) represented an incremental increase. It remains unclear to what extent these low-density infections may contribute to the infectious reservoir in different malaria transmission settings.

Distribution and temporal dynamics of P. falciparum chloroquine resistance transporter mutations associated with piperaquine resistance in Northern Cambodia

BACKGROUND

Newly emerged mutations within the Plasmodium falciparum chloroquine resistance transporter (PfCRT) can confer piperaquine resistance in the absence of amplified plasmepsin II (pfpm2). In this study, we estimated the prevalence of co-circulating piperaquine resistance mutations in P. falciparum isolates collected in northern Cambodia from 2009-2017.

METHODS

The sequence of pfcrt was determined for 410 P. falciparum isolates using PacBio amplicon sequencing or whole genome sequencing. Quantitative PCR was used to estimate pfpm2 and pfmdr1 copy number.

RESULTS

Newly emerged PfCRT mutations increased in prevalence after the change to dihydroartemisinin-piperaquine in 2010, with >98% of parasites harboring these mutations by 2017. After 2014, the prevalence of PfCRT F145I declined, being out-competed by parasites with less resistant, but more fit PfCRT alleles. After the change to artesunate-mefloquine, the prevalence of parasites with amplified pfpm2 decreased, with nearly half of piperaquine-resistant PfCRT mutants having single copy pfpm2.

CONCLUSIONS

The large proportion of PfCRT mutants that lack pfpm2 amplification emphasizes the importance of including PfCRT mutations as part of molecular surveillance for piperaquine resistance in this region. Likewise, it is critical to monitor for amplified pfmdr1 in these PfCRT mutants, as increased mefloquine pressure could lead to mutants resistant to both drugs.

[Efficacy and safety of Kangbingdu granules in the treatment of influenza: a randomized, double-blind, double-dummy, positive-drug parallel control multicenter clinical trial]

Objective: To observe the efficacy and safety of Kangbingdu granules (KBD) in the treatment of influenza. Methods: A multicenter, randomized, double-blind, double-dummy, and positive-drug parallel control trial was conducted in 27 Grade ⅢA hospitals in China and the subjects were randomly assigned to the KBD test group or the oseltamivir phosphate capsule control group at a ratio of 1∶1. 200 subjects were planned to be enrolled in each group. The experimental group was given KBD (18g each time, 3 times a day) and oseltamivir phosphate simulator orally, while the control group was given oseltamivir phosphate capsule (75 mg each time, twice a day) and KBD simulator orally for 5 days. The primary efficacy indicators included the remission time of major clinical symptoms and the time of complete defervescence. The secondary efficacy indicators included dosage of acetaminophen, the change of traditional Chinese medicine (TCM) syndrome score and the remission time of other important clinical symptoms. The efficacy of KBD in the test group and Oseltamivir phosphate control group were compared. Adverse events or adverse reactions were observed at the same time to evaluate the safety of KBD Granules. Results: A total of 393 subjects from 27 Grade ⅢA hospitals in China were enrolled. The experimental group included 195 subjects and 191 subjects (97.95%) completed the trial, While the control group included 198 subjects and 195 subjects (98.48%) completed the trial. There was no significant difference in the shedding rate and rejection rate between the two groups (P>0.05). In the Full Analysis Set (FAS), the mean age of the experimental group was (34.9±14.4) years old, with 83 males (42.78%). The mean age of the control group was (33.3±13.5) years old, with 78 males (39.59%). There were no statistically significant differences between the two groups in demographic data, physical examination, viral pathogen detection, total score of TCM syndromes and scores of each symptom at baseline (P>0.05). In the FAS, the remission time M (Q₁, Q₃) of major clinical symptoms was 3.0 (3.0, 4.0) days in the experimental group and 3.0 (3.0, 4.0) days in the control group, and the difference was not statistically significant (P>0.05). The time M (Q₁, Q₃) of complete defervescence was 34.0 (20.3, 49.0) hours in the experimental group and 36.5 (19.6, 48.8) hours in the control group, and the difference was not statistically significant (P>0.05). KBD granules had the same effect as Oseltamivir phosphate capsule (P>0.05) in terms of acetaminophen dosage, TCM syndrome effect and disappearance rate of most important clinical symptoms. Meanwhile, the disappearance rate of dizziness and chest distress on day 3 in the KBD granules group was better than that of oseltamivir phosphate capsule (P<0.05). Conclusion: KBD granules have the same efficacy as Oseltamivir Phosphate capsule in the treatment of influenza and the drug safety is good.

[Evaluation of the effectiveness of bronchial thermoplasty in patients with severe asthma in the real world two years after bronchial thermoplasty treatment]

Objective: To assess the effectiveness of bronchial thermoplasty (BT) in "real-world" patients with severe asthma at 2 years post therapy. Method: Outcomes of 70 patients with severe asthma undergoing bronchial thermoplasty from March 2014 to November 2017 in China-Japan Friendship Hospital were retrospectively analyzed two years post therapy. The scores of Asthma Control Test (ACT) and Mini Asthma Quality of Life Questionnaire (mini-AQLQ), the number of severe exacerbations, emergency department visits and hospitalizations for asthma symptoms in the past year, indicators of pulmonary function including forced expiratory volume in one second (FEV(1)), FEV(1) as a percentage of predicted value (FEV(1)%pred) and FEV(1)/forced vital capacity (FEV(1)/FVC), maintenance asthma medications, the cost of asthma drugs and the total annual cost of asthma treatment were evaluated and analyzed before and 2 years after BT therapy, and the subjective assessment about effectiveness of BT were given by the patients. Results: Before and 2 years after BT, the numbers of subjects suffering severe exacerbations in the past year were 70 (100%) and 37 (52.9%), and the numbers of total severe exacerbations were 575 and 162 respectively. The numbers of patients having emergency department visits due to asthma exacerbation were 46 (65.7%) and 9 (12.9%), and the numbers of emergency department visits were 186 and 19 respectively. The numbers of patients hospitalized due to asthma exacerbation were 43 (61.4%) and 16 (22.9%), and the numbers of total hospitalizations were 124 and 24, respectively. The rate of severe exacerbation, emergency department visit and hospitalization were significantly reduced two years after the treatment by 71.9%, 88.9% and 83.3% (all P<0.001). The scores of ACT and mini-AQLQ were significantly increased [22 (21, 24) vs 17 (13, 19), (5.57±0.89) vs (3.83±0.92); both P<0.001]. Two years after BT, 4 patients (5.7%) were weaned off inhaled corticosteroids (ICS) and long-acting β(2)-agonist (LABA), while 14 patients (37.8%) were weaned off oral corticosteroid (OCS), with daily dose of ICS and OCS significantly decreased (both P<0.05). The proportion of patients treated with montelukast sodium and theophylline was also significantly reduced after BT (40.0% vs 81.4%, 27.1% vs 71.4%; both P<0.001). In addition, the indicator of FEV(1), FEV(1)%pred and FEV(1)/FVC ratio were all greatly improved two years after the treatment [2.27 (1.84, 2.82) vs 2.10 (1.70, 2.61) L, (76.8±19.5)% vs (72.5±19.8)%, (66.3±13.6)% vs (63.8±13.0)%; all P<0.05]. The annual cost for asthma drug and asthma treatment after BT were significantly decreased (P<0.001). Fifty-nine patients (84.3%) subjectively assessed the treatment as effective. Conclusion: The bronchial thermoplasty in "real-world" patients with severe asthma could significantly improve the asthma control, lung function and quality of life, and reduce severe exacerbations, emergency department visits and hospitalizations for asthma symptoms, while the maintenance asthma medications, the cost of asthma drugs and the total annual cost of asthma treatment are significantly decreased.

[Effects of bronchial thermoplasty on airway remodeling, asthma control and quality of life in patients with severe asthma]

Objective: To investigate the effects of bronchial thermoplasty (BT) on airway remodeling, asthma control and quality of life in patients with severe asthma. Methods: From January to September 2019, 11 patients with severe asthma were recruited from China Japan Friendship Hospital to receive BT treatment. The treatment was performed over three sessions separated by 3-week intervals. The right lower lobe, the left lower lobe and the bilateral upper lobes were treated respectively. In this study, patients' self-control method was used. The timepoint before the first BT treatment was defined as pre-treatment group, and the timepoint before the third treatment was defined as post-treatment group. Histological staining was used to detect the airway remodeling of the left lower lobe in two groups, including the mass of airway smooth muscle (ASM) and collagen in airway wall, and the thickness of basement membrane. The cell classification of bronchoalveolar lavage fluid (BALF) from the left lower lobe and peripheral blood, total serum IgE, asthma control test (ACT), mini asthma quality of life questionnaire (miniAQLQ) and the forced expiratory volume in 1 second expressed as percent predicted (FEV(1)%pred) were evaluated in the two groups. The correlation was analyzed between airway remodeling and asthma control and quality of life. Results: Effects of BT in post-treatment group, compared with pre-treatment group: the mass of ASM and collagen in airway wall was significantly decreased [(9.8±2.5)% vs (25.8±7.7)%, (12.9±4.0)% vs (17.4±5.6)%] (both P<0.05), while basement membrane thickness was not significantly different (P>0.05); the percentage of eosinophils in BALF and peripheral blood, and total serum IgE were not significantly different (all P>0.05); ACT score and miniAQLQ score were significantly increased [(23.1±1.8) vs (13.8±6.2) points, (5.3±1.3) vs (3.6±1.5) points] (both P<0.05), while FEV(1)% pred was not statistically different (P>0.05). The mass of ASM was negatively correlated with ACT score (r=-0.712), miniAQLQ score (r=-0.557) and FEV(1)%pred (r=-0.477), while the mass of collagen was negatively correlated with ACT score (r=-0.549) and miniAQLQ score (r=-0.639) (all P<0.05). Conclusion: BT treatment could improve airway remodeling, asthma control and quality of life in patients with severe asthma; besides, the reduction of remodeling is related to the improvements of asthma control and quality of life.

[An epidemiological survey on clinical features, self-management and cognitive level of elderly asthmatics in China]

Objective: To investigate the prevalence of asthma among the elderly people in China and to analyze the clinical features, self-management and cognitive level of elderly asthma patients. Methods: According to the multi-stage random cluster sampling methods, a total of 164 215 subjects were visited by a questionnaire in the last epidemiology survey from eight provinces (Beijing, Shanghai, Guangdong, Liaoning, Henan, Shanxi, Jiangsu, Sichuan provinces) and seven regions (north, northeast, southern china, east, south, southwest and northwest) in China from February 2010 to August 2012. 2 034 were diagnosed as asthma. The elderly patients aged ≥65 years were selected from the 2 034 asthma patients. The clinical characteristics, comorbidities, the status of asthma control and self-management and insights of the disease in elderly asthma patients were analyzed. Results: Among the 2 034 asthma patients, 584 (28.7%) were elderly asthmatics aged ≥65 years old and 1 450 (71.3%) were<65 years old. In the elderly asthma group, Early-onset asthma accounted for 439 (75.2%) and 145 (24.8%) were late-onset. The common clinical manifestations of elderly asthma patients were: chest distress 395 (67.6%), wheezing 304 (52.1%), cough 298 (51.0%). Common comorbidities of elderly asthmatics were: chronic obstructive pulmonary disease 144 (24.7%), allergic rhinitis 122(20.9%), gastroesopheal reflux disease (GERD) 114(19.5%), allergic conjunctivitis 86 (14.7%), eczema 82 (14.0%), chronic bronchitis 76 (13.0%). The Asthma Control Test (ACT) scores of elderly asthmatics and non-elderly asthmatics were (18.5±3.2) and (21.7±3.4) respectively. There was a significant difference between the two groups (P=0.042). Of the elderly asthmatics, only 13 (2.2%) patients monitored daily using a peak flow meter. 93 (15.9%) patients aware that asthma was characterized by chronic airway inflammation. 64 (11.0%) asthmatics understood that the treatment goal. Conclusions: The clinical manifestations of elderly asthmatics are atypical, especially paroxysmal wheezing. Asthma in elderly people causes more comorbidities and mortality. The self-management and cognitive level of patients with asthma needs to be improved.

[Experts consensus for the diagnosis, treatment, and prevention of Coronavirus disease 2019 in the elderly]

Coronavirus disease 2019 (COVID-19) can cause great damage to the elderly patients and lead to high mortality. The clinical presentations and auxiliary examinations of the elderly patients with COVID-19 are atypical, due to the physiological ageing deterioration and basal pathological state. The treatment strategy for the elderly patients has its own characteristics and treatment protocol should be considered accordingly. To improve the diagnosis, treatment, and prevention of COVID-19 in the elderly, the Expert Committee of Geriatric Respiratory and Critical Care Medicine, China Society of Geriatrics established the "Expert consensus for the diagnosis, treatment, and prevention of Coronavirus disease 2019 in the elderly" . We focused on the clinical characteristics and key points for better treatment and prevention of COVID-19 in the elderly. (1) For diagnosis, atypical clinical presentation of COVID-19 in the elderly should be emphasized, which may be complicated by underlying disease. (2) For treatment, strategy of multiple disciplinary team (mainly the respiratory and critical care medicine) should be adopted and multiple systemic functions should be considered. (3) For prevention, health care model about integrated management of acute and chronic diseases, in and out of hospital should be applied.

[A survey on clinical characteristics and risk factors of severe asthma in China]

Objective: To investigate the clinical characteristics and risk factors of severe bronchial asthma in Chinese people over 14 years old. Methods: According to the multi-stage random cluster sampling methods, a total of 164 215 subjects were visited by a questionnaire in the epidemiology survey from eight provinces (Beijing, Shanghai, Guangdong, Liaoning, Henan, Shanxi, Jiangsu, Sichuan provinces) located in seven regions (north, northeast, east, central China, south, southwest and northwest) of China from February 2010 to August 2012. A total of 2 034 were diagnosed as asthma. The clinical characteristics and related risk factors of patients with severe asthma in China were analyzed. Results: Among all asthma patients, 560 were newly diagnosed, accounting for 27.5% (560/2 034) and the percentage of previously confirmed patients was 72.5% (1 474/2 034). A total of 145 were eligible for severe asthma, accounting for 9.8% (145/1 474) of previously confirmed asthmatics and 7.1% (145/2 034) of all asthmatics. 83.5% (121/145) severe asthmatics had at least one trigger factor. Correlation analysis showed that the risk factors of severe asthma were: smoking (OR=1.543, 95%CI: 1.250-1.814), obesity (OR=2.186, 95%CI: 1.972-2.354), petting (OR=2.135, 95%CI: 1.904-2.283), combined with allergic rhinitis (OR=3.456, 95%CI: 2.721-4.326), gastroesophageal reflux disease (OR=1.842, 95%CI: 1.682-2.140), bronchiectasis (OR=1.665, 95%CI: 1.347-1.912) or chronic obstructive pulmonary disease (OR=1.312, 95%CI: 1.171-1.694). Conclusions: The most common comorbidities in severe asthmatics in China are allergic rhinitis and gastroesophageal reflux disease. The risk factors of severe asthma include obesity, allergic rhinitis, gastroesophageal reflux disease, chronic obstructive pulmonary disease, bronchiectasis, smoking and petting.

Prevalence of CYP2D6 Genotypes and Predicted Phenotypes in a Cohort of Cambodians at High Risk for Infections with Plasmodium vivax

Clinical failure of primaquine (PQ) has been demonstrated in people with CYP450 2D6 genetic polymorphisms that result in reduced or no enzyme activity. The distribution of CYP2D6 genotypes and predicted phenotypes in the Cambodian population is not well described. Surveys in other Asian countries have shown an approximate 50% prevalence of the reduced activity CYP2D6 allele *10, which could translate into increased risk of PQ radical cure failure and repeated relapses, making interruption of transmission and malaria elimination difficult to achieve. We determined CYP2D6 genotypes from 96 volunteers from Oddor Meanchey Province, Cambodia, an area endemic for Plasmodium vivax. We found a 54.2% frequency of the *10 allele, but in approximately half of our subjects, it was paired with a normal activity allele, either *1 or *2. The prevalence of *5, a null allele, was 9.4%. Overall predicted phenotype percentages were normal metabolizers, 46%; intermediate metabolizers, 52%; and poor metabolizers, 1%.

Relapse or reinfection: Classification of malaria infection using transition likelihoods

In patients with Plasmodium vivax malaria treated with effective blood-stage therapy, the recurrent illness may occur due to relapse from latent liver-stage infection or reinfection from a new mosquito bite. Classification of the recurrent infection as either relapse or reinfection is critical when evaluating the efficacy of an anti-relapse treatment. Although one can use whether a shared genetic variant exists between baseline and recurrence genotypes to classify the outcome, little has been suggested to use both sharing and nonsharing variants to improve the classification accuracy. In this paper, we develop a novel classification criterion that utilizes transition likelihoods to distinguish relapse from reinfection. When tested in extensive simulation experiments with known outcomes, our classifier has superior operating characteristics. A real data set from 78 Cambodian P. vivax malaria patients was analyzed to demonstrate the practical use of our proposed method.

Efficient Transmission of Mixed Plasmodium falciparum/vivax Infections From Humans to Mosquitoes

BACKGROUND

In Southeast Asia, people are often coinfected with different species of malaria (Plasmodium falciparum [Pf] and Plasmodium vivax [Pv]) as well as with multiple clones of the same species. Whether particular species or clones within mixed infections are more readily transmitted to mosquitoes remains unknown.

METHODS

Laboratory-reared Anopheles dirus were fed on blood from 119 Pf-infected Cambodian adults, with 5950 dissected to evaluate for transmitted infection. Among 12 persons who infected mosquitoes, polymerase chain reaction and amplicon deep sequencing were used to track species and clone-specific transmission to mosquitoes.

RESULTS

Seven of 12 persons that infected mosquitoes harbored mixed Pf/Pv infection. Among these 7 persons, all transmitted Pv with 2 transmitting both Pf and Pv, leading to Pf/Pv coinfection in 21% of infected mosquitoes. Up to 4 clones of each species were detected within persons. Shifts in clone frequency were detected during transmission. However, in general, all parasite clones in humans were transmitted to mosquitoes, with individual mosquitoes frequently carrying multiple transmitted clones.

CONCLUSIONS

Malaria diversity in human hosts was maintained in the parasite populations recovered from mosquitoes fed on their blood. However, in persons with mixed Pf/Pv malaria, Pv appears to be transmitted more readily, in association with more prevalent patent gametocytemia.

Errors in Diagnostic Test Use and Interpretation Contribute to the High Number of Lyme Disease Referrals in a Low-Incidence State

Lyme disease accounted for more than two-thirds (56 of 81, 69.1%) of all tick-borne disease referrals to a large, academic infectious diseases clinic in a low-incidence state. Deviations from diagnostic testing guidelines and errors in test interpretation were common (23 of 35, 65.7%), suggesting that frontline providers need additional clinical support.

[Effect of artesunate on airway responsiveness and airway inflammation in asthmatic mice]

Objective: To observe the effects of artesunate on airway responsiveness and airway inflammation in asthmatic mice. Methods: Thirty female BALB/c mice aged 6-8 weeks were randomly divided into control group, asthma group and artesunate group. In the asthma group and the artesunate group, the mice were sensitized by intraperitoneal injection of 20 μg of ovalbumin (OVA) and 0.2 ml of aluminum hydroxide suspension (2 mg) on day 0 and 14, respectively, and 1% OVA 10 ml dissolved in sterile phosphate (PBS) buffer was aerosolized for 30 min from the 21st to 28th day. The control group was sensitized with 0.2 ml of 2 mg suspension of aluminum hydroxide on day 0 and 14, and aerosolized by 10 ml of sterile PBS from the 21st to 28th day. Before the challenge, the artesunate group was intraperitoneally injected with 0.2 ml of artesunate. Artesunate was replaced with the same amount of normal saline in the control group and the asthma group. The mice were treated after 24 hours of last stimulation. The airway responsiveness of mice was measured by airway intubation and the changes of airway resistance and compliance were observed. Bronchoalveolar lavage fluid (BALF) was classified by cytology, and pathological changes of left lung tissue were observed and scored. Results: The airway resistance of the three groups increased and the lung compliance decreased with the increase of methacholine (Ach) concentration. The airway resistance and lung compliance of the three groups were different under the same concentration (P<0.05). The airway resistance of the artesunate group at Ach 6.25, 12.5, 25, 50, 100 mg/ml was lower than that of the asthma group at the same concentration [(1.01±0.48) vs (1.30±0.22), (1.06±0.44) vs (1.70±0.31), (1.30±0.64) vs (2.66±0.79), (1.82±0.55) vs (3.38±1.35), (2.49±0.85) vs (4.07±1.34) cmH(2)O·s(-1)·ml(-1)(1 cmH(2)O=0.098 kPa); t=3.862, 7.376, 9.113, 7.051, 6.685, all P<0.05]; the degree of lung compliance decrease at the concentration of Ach 3.125, 6.25, 12.5, 25, 50, 100 mg/ml was lower than that of the asthma group at the same concentration [(3.89±0.55)×10(-2) vs (3.07±0.63)×10(-2), (3.61±0.52)×10(-2) vs (3.04±0.58)×10(-2), (3.48±0.38)×10(-2) vs (2.78±0.57)×10(-2), (3.09±0.52)×10(-2) vs (1.73±0.62)×10(-2), (2.32±0.60)×10(-2) vs (1.29±0.54)×10(-2), (1.87±0.59)×10(-2) vs (1.15±0.44)×10(-2) ml/cmH(2)O; t=-6.295, -4.921, -6.533, -11.135, -8.48, -6.319, all P<0.05]. The proportion of eosinophils in artesunate group in BALF was significantly lower than that in asthma group [(16.63±8.58)% vs (40.44±12.94)%; t=4.336, P<0.05]. In the asthma group, the inflammatory cells infiltration of the bronchi and the perivascular area, the bronchial epithelial edema and degeneration can be observed, and the artesunate could reduce the infiltration of inflammatory cells around the bronchus and blood vessels, and the mucus secretion was also reduced in the artesunate group. Conclusion: Artesunate can improve airway hyperresponsiveness and airway inflammation in asthmatic mice and has a certain therapeutic effect on asthma.

Gametocyte Carriage, Antimalarial Use, and Drug Resistance in Cambodia, 2008-2014

Gametocytes are the malaria parasite stages responsible for transmission from humans to mosquitoes. Gametocytemia often follows drug treatment, especially as therapies start to fail. We examined Plasmodium falciparum gametocyte carriage and drug resistance profiles among 824 persons with uncomplicated malaria in Cambodia to determine whether prevalent drug resistance and antimalarial use has led to a concentration of drug-resistant parasites among gametocyte carriers. Although report of prior antimalarial use increased from 2008 to 2014, the prevalence of study participants presenting with microscopic gametocyte carriage declined. Gametocytemia was more common in those reporting antimalarial use within the past year, and prior antimalarial use was correlated with higher IC₅₀s to piperaquine and mefloquine, as well as to increased pfmdr1 copy number. However, there was no association between microscopic gametocyte carriage and parasite drug resistance. Thus, we found no evidence that the infectious reservoir, marked by those carrying gametocytes, is enriched with drug-resistant parasites.

[Distribution of airway inflammation phenotype in patients with bronchial asthma and its correlation with control level]

Objective: To investigate the distribution of airway inflammation phenotypes in patients with bronchial asthma and its correlation with asthma control level. Methods: Patients who met GINA 2017 asthma diagnostic criteria from October 2017 to April 2018 in respiratory outpatient department of China-Japan Friendship Hospital were included. The clinical data of non-acute asthma patients were prospectively collected, including general data, asthma control level, pulmonary function, induced sputum cell classification, serum total IgE, exhaled nitric oxide (FeNO), blood cell classification. The correlation between phenotype distribution of airway inflammation and airway inflammation markers (eosinophils in sputum, FeNO, blood eosinophil, serum IgE) and asthma control was analyzed by correlation analysis. The correlation between sputum eosinophil level and FeNO, blood eosinophil count, serum total IgE, forced expiratory volume in one-second (FEV(1)) predicted (FEV(1)%pred) was analyzed by correlation analysis too. Results: A total of 97 asthmatic patients were enrolled. There were 38 males (39.2%) and 59 females (60.8%), aged (48±14) (range 22 to 80). Control level of asthma:13 cases (13.4%) were controlled, 39 cases(40.2%) were partially controlled and 45 cases (46.4%) were uncontrolled. The phenotypes of airway inflammation were eosinophilic 51 cases (52.6%), neutrophilic 9 cases (9.3%), mixed 35 cases (36.1%) and paucigranulocytic 2 cases (2.1%). There was no significant correlation between airway inflammation phenotype distribution, airway inflammation markers and asthma control level (P>0.05). Sputum eosinophil level was positively correlated with FeNO level in controlled and uncontrolled patients (r=0.420, P=0.008 and r=0.325, P=0.031); sputum eosinophil level was positively correlated with blood eosinophil level in uncontrolled asthma patients (r=0.328, P=0.037). There was no significant correlation between sputum eosinophil level and FEV(1)%pred (P>0.05). Conclusions: Eosinophil type is the dominant type of airway inflammation in asthmatic patients, and there is no significant correlation between airway inflammation and asthma control level. At present, airway inflammation cannot be used to assess asthma control level.