Clinical evaluation of a novel digital microfluidic based point-of-care test platform for detection of SARS-Cov-2 and influenza A/B.

Respiratory pathogens, such as SARS-CoV-2 and influenza A/B, can cause severe illnesses in susceptible individuals. This research evaluated a novel digital microfluidic point-of-care testing platform designed to detect 23 pathogens, comparing its performance to conventional laboratory-based nucleic acid tests. The platform integrates nucleic acid extraction and amplification processes for rapid detection with only 2 min of hands-on time. Performance assays demonstrated that the platform has high sensitivity (87 %-100 %) and specificity (99 %-100 %) for the detection of the evaluated 3 viruses. Additionally, the platform can be adapted for the detection of other respiratory pathogens, aiding in the early diagnosis of respiratory diseases, identifying the source of an outbreak or epidemic, and curbing the spread of the disease.

Hepatitis C virus subtype diversity and transmission clusters characteristics among drug users in Zhuhai, South China.

BACKGROUND: Hepatitis C virus (HCV) infection poses a major public health challenge globally, especially among injecting drug users. China has the world's largest burden of HCV infections. However, little is known about the characteristics of transmission networks among drug user populations. This study aims to investigate the molecular epidemiology and transmission characteristics of HCV infections among drug users in Zhuhai, a bustling port city connecting Mainland China and its Special Administrative Regions. METHODS: Participants enrolled in this study were drug users incarcerated at Zhuhai's drug rehabilitation center in 2015. Their sociodemographic and behavioral information, including gender, promiscuity, drug use method, and so forth, was collected using a standardized questionnaire. Plasmas separated from venous blood were analyzed for HCV infection through ELISA and RT-PCR methods to detect anti-HCV antibodies and HCV RNA. The 5'UTR fragment of the HCV genome was amplified and further sequenced for subtype identifications and phylogenetic analysis. The phylogenetic tree was inferred using the Maximum Likelihood method based on the Tamura-Nei model, and the transmission cluster network was constructed using Cytoscape3.8.0 software with a threshold of 0.015. Binary logistic regression models were employed to assess the factors associated with HCV infection. RESULTS: The overall prevalence of HCV infection among drug users was 44.37%, with approximately 19.69% appearing to clear the HCV virus successfully. Binary logistic regression analysis revealed that those aged over 40, engaging in injecting drug use, and being native residents were at heightened risk for HCV infection among drug user cohorts. The predominant HCV subtypes circulating among those drug users were 6a (60.26%), followed by 3b (16.7%), 3a (12.8%), 1b (6.41%) and 1a (3.85%), respectively. Molecular transmission network analysis unveiled the presence of six transmission clusters, with the largest propagation cluster consisting of 41 individuals infected with HCV subtype 6a. Furthermore, distinct transmission clusters involved eight individuals infected with subtype 3b and seven with subtype 3a were also observed. CONCLUSION: The genetic transmission networks revealed a complex transmission pattern among drug users in Zhuhai, emphasizing the imperative for a targeted and effective intervention strategy to mitigate HCV dissemination. These insights are pivotal for shaping future national policies on HCV screening, treatment, and prevention in port cities.

A syndromic diagnostic assay on a macrochannel-to-digital microfluidic platform for automatic identification of multiple respiratory pathogens.

The worldwide COVID-19 pandemic has changed people's lives and the diagnostic landscape. The nucleic acid amplification test (NAT) as the gold standard for SARS-CoV-2 detection has been applied in containing its transmission. However, there remains a lack of an affordable on-site detection system at resource-limited areas. In this study, a low cost "sample-in-answer-out" system incorporating nucleic acid extraction, purification, and amplification was developed on a single macrochannel-to-digital microfluidic chip. The macrochannel fluidic subsystem worked as a world-to-chip interface receiving 500-1000 µL raw samples, which then underwent bead-based extraction and purification processes before being delivered to DMF. Electrodes actuate an eluent dispensed to eight independent droplets for reverse transcription quantitative polymerase chain reaction (RT-qPCR). By reading with 4 florescence channels, the system can accommodate a maximum of 32 detection targets. To evaluate the proposed platform, a comprehensive assessment was conducted on the microfluidic chip as well as its functional components (i.e., extraction and amplification). The platform demonstrated a superior performance. In particular, using clinical specimens, the chip targeting SARS-CoV-2 and Flu A/B exhibited 100% agreement with off-chip diagnoses. Furthermore, the fabrication of chips is ready for scaled-up manufacturing and they are cost-effective for disposable use since they are assembled using a printed circuit board (PCB) and prefabricated blocks. Overall, the macrochannel-to-digital microfluidic platform coincides with the requirements of point-of-care testing (POCT) because of its advantages: low-cost, ease of use, comparable sensitivity and specificity, and availability for mass production.

Late-Onset Nail Changes Associated with Hand, Foot, and Mouth Disease: A Clinical Analysis of 56 Cases.

OBJECTIVES: To investigate the development and clinical characteristics of nail changes in hand, foot, and mouth disease (HFMD). METHODS: A telephone survey was conducted with the parents of patients diagnosed with HFMD in the Fourth General Hospital of Nanhai from June to August 2013 to document nail changes within 3 months of diagnosis of HFMD. RESULTS: Valid survey results were obtained from 273 cases. Definitive nail changes were identified in 56 patients (20.5%). More boys (25.8%) than girls (10.6%) (p < 0.01) showed changes. The age distribution ranged from 1 to 5 years, and nail changes were rare in children younger than 1 year of age (p < 0.01). Nail changes were usually seen 1 to 2 months after the onset of HFMD and lasted for 1 to 8 weeks, most for approximately 4 weeks. Toenails or fingernails could be affected and the changes were more likely to occur synchronously. Fingernails were more commonly involved than toenails. When both fingernails and toenails were involved, this typically occurred synchronously. Although there were cases with all toenails and fingernails involved (16.1%), we did not encounter any instances involving 13 to 19 nails. The nail changes mainly presented as onychomadesis. Spontaneous recovery without special treatment was the course for all patients. No relapse or new nail involvement was identified. CONCLUSIONS: Nail change associated with HFMD usually occurs within 1 to 2 months after onset, mainly presents as onychomadesis, and is a self-limited process. Possible mechanisms are discussed.

[Hemagglutinin gene of influenza A (H3N2) virus from human samples in the 2009 influenza epidemic in Chengdu].

OBJECTIVE: To study the antigenic and genetic characteristics of influenza A (H3N2) virus in the 2009 influenza epidemics in Chengdu. METHODS: The influenza virus strains were isolated with MDCK cells from 4869 samples taken from the sentinel surveillance in 2009 in Chengdu. Hemagglutination inhibition (HI) and RT-PCR reaction tests were performed to guide the extraction of viral RNA from the culture fluid of the influenza A (H3N2) virus. The hemagglutinin gene was obtained by RT-PCR and sequenced. RESULTS: The separation rates of swine influenza H1N1, H3N2, H1N1, and B were 25.2%, 7.2%, 4.5%, and 1.5% respectively. The epidemic peaked in summer and autumn. Four amino acids changed in A, B, and D antigenic and receptor binding sites: site160N>K, site174K>R/N, site189K>Q, site277R>Q. Glycosylation sites were inserted to sitel60 or absent at site181 in some isolated strains. CONCLUSION: Swine influenza H1N1 viruses dominated the 2009 Chengdu epidemic, with H3N2, H1N1, and B strains coexisting. The influenza A(H3N2) viruses had gene variations due to antigenic drift.

[Carrying rate of Neissria meningitides in a healthy population in the Mianzhu post-earthquake residential area].

OBJECTIVE: To predict the possibility of epidemic outbreak of meningitis by testing Neissria Meningitides in a healthy population in the Mianzhu post-earthquake residential area. METHODS: A simple random sampling strategy was adopted to collect 887 throat swabs from a healthy population in the Mainzhu post-earthquake residential area. The TaqMan assay were performed to detect Neissria Meningitides. RESULTS: Three positive samples were identified. CONCLUSION: The carrying rate of Neissria Meningitides is not high enough to bring about an epidemic outbreak of Meningitis. However, efforts to maintain a hygienic environment in the post-earthquake residential area should be continued.