Abstract
Background
Improved understanding of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spectrum of disease is essential for clinical and public health interventions. There are ...limited data on mild or asymptomatic infections, but recognition of these individuals is key as they contribute to viral transmission. We describe the symptom profiles from individuals with mild or asymptomatic SARS-CoV-2 infection.
Methods
From 22 March to 22 April 2020 in Wisconsin and Utah, we enrolled and prospectively observed 198 household contacts exposed to SARS-CoV-2. We collected and tested nasopharyngeal specimens by real-time reverse-transcription polymerase chain reaction (rRT-PCR) 2 or more times during a 14-day period. Contacts completed daily symptom diaries. We characterized symptom profiles on the date of first positive rRT-PCR test and described progression of symptoms over time.
Results
We identified 47 contacts, median age 24 (3–75) years, with detectable SARS-CoV-2 by rRT-PCR. The most commonly reported symptoms on the day of first positive rRT-PCR test were upper respiratory (n = 32 68%) and neurologic (n = 30 64%); fever was not commonly reported (n = 9 19%). Eight (17%) individuals were asymptomatic at the date of first positive rRT-PCR collection; 2 (4%) had preceding symptoms that resolved and 6 (13%) subsequently developed symptoms. Children less frequently reported lower respiratory symptoms (21%, 60%, and 69% for <18, 18–49, and ≥50 years of age, respectively; P = .03).
Conclusions
Household contacts with laboratory-confirmed SARS-CoV-2 infection reported mild symptoms. When assessed at a single timepoint, several contacts appeared to have asymptomatic infection; however, over time all developed symptoms. These findings are important to inform infection control, contact tracing, and community mitigation strategies.
This paper presents a lab-chip immunoassay system that is based on AC electrothermal effect. It uses a poly (dimethylsiloxane) based microfluidic cartridge as the disposable immunoreactor, on which ...key processes such as reagent delivery, incubation and washing are performed using low voltage AC signals. A low cost, reconfigurable detection module is constructed based on light emitting diode induced fluorescence. Along with the employed AC electrothermal effect, the developed diagnostic system has demonstrated a much shorter incubation time than conventional pressure driven flow system. A tenfold acceleration in detection is achieved while safely differentiating between the positive and negative primary antibodies with large margin. Other merits of this immunoassay system include portability, rapid detection and low reagent consumption.
Abstract
Background
In 2018, the Centers for Disease Control and Prevention and the Vermont Department of Health investigated an outbreak of multidrug-resistant Shigella sonnei infections in a ...retirement community that offered a continuum of care from independent living through skilled nursing care. The investigation identified 24 culture-confirmed cases. Isolates were resistant to trimethoprim-sulfamethoxazole, ampicillin, and ceftriaxone, and had decreased susceptibility to azithromycin and ciprofloxacin.
Methods
To evaluate clinical and microbiologic response, we reviewed inpatient and outpatient medical records for treatment outcomes among the 24 patients with culture-confirmed S. sonnei infection. We defined clinical failure as diarrhea (≥3 loose stools per day) for ≥1 day after treatment finished, and microbiologic failure as a stool culture that yielded S. sonnei after treatment finished. We used broth microdilution to perform antimicrobial susceptibility testing, and whole genome sequencing to identify resistance mechanisms.
Results
Isolates contained macrolide resistance genes mph(A) and erm(B) and had azithromycin minimum inhibitory concentrations above the Clinical and Laboratory Standards Institute epidemiological cutoff value of ≤16 µg/mL. Among 24 patients with culture-confirmed Shigella infection, 4 were treated with azithromycin; all had clinical treatment failure and 2 also had microbiologic treatment failure. Isolates were susceptible to ciprofloxacin but contained a gyrA mutation; 2 patients failed treatment with ciprofloxacin.
Conclusions
These azithromycin treatment failures demonstrate the importance of clinical breakpoints to aid clinicians in identifying alternative treatment options for resistant strains. Additionally, these treatment failures highlight a need for comprehensive susceptibility testing and systematic outcome studies, particularly given the emergence of multidrug-resistant Shigella among an expanding range of patient populations.
Among 24 patients in a multidrug-resistant Shigella outbreak, 4 were treated with azithromycin; all had clinical treatment failure (persistent diarrhea) and 2 also had microbiologic failure (stool culture yielding Shigella sonnei). Additionally, 2 patients failed treatment with ciprofloxacin (1 clinical, 1 microbiologic).
Abstract
Background
Coronavirus disease 2019 (COVID-19) continues to cause significant morbidity and mortality worldwide. Correctional and detention facilities are at high risk of experiencing ...outbreaks. We aimed to evaluate cohort-based testing among detained persons exposed to laboratory-confirmed cases of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in order to identify presymptomatic and asymptomatic cases.
Methods
During 1–19 May 2020, 2 testing strategies were implemented in 12 tiers or housing units of the Cook County Jail, Chicago, Illinois. Detained persons were approached to participate in serial testing (n = 137) and offered tests at 3 time points over 14 days (day 1, days 3–5, and days 13–14). The second group was offered a single test and interview at the end of a 14-day quarantine period (day 14 group) (n = 87).
Results
224 detained persons were approached for participation and, of these, 194 (87%) participated in ≥1 interview and 172 (77%) had ≥1 test. Of the 172 tested, 19 were positive for SARS-CoV-2. In the serial testing group, 17 (89%) new cases were detected, 16 (84%) on day 1, 1 (5%) on days 3–5, and none on days 13–14; in the day 14 group, 2 (11%) cases were identified. More than half (12/19; 63%) of the newly identified cases were presymptomatic or asymptomatic.
Conclusions
Our findings highlight the utility of cohort-based testing promptly after initiating quarantine within a housing tier. Cohort-based testing efforts identified new SARS-CoV-2 asymptomatic and presymptomatic infections that may have been missed by symptom screening alone.
Our findings suggest that early cohort-based testing in detained persons helped identify new SARS-CoV-2 asymptomatic and presymptomatic infections that may have been missed by symptom screening alone. Frequency of testing may be dependent on status of outbreak in the facility.
Rabies surveillance in the United States during 2015 Birhane, Meseret G; Cleaton, Julie M; Monroe, Ben P ...
Journal of the American Veterinary Medical Association,
2017-May-15, Letnik:
250, Številka:
10
Journal Article
Recenzirano
Odprti dostop
OBJECTIVE To describe rabies and rabies-related events occurring during 2015 in the United States. DESIGN Observational study based on passive surveillance data. ANIMALS All animals submitted for ...rabies testing in the United States during 2015. PROCEDURES State and territorial public health programs provided data on animals submitted for rabies testing in 2015. Data were analyzed temporally and geographically to assess trends in domestic and sylvatic animal rabies cases. RESULTS During 2015, 50 states and Puerto Rico reported 5,508 rabid animals to the CDC, representing an 8.7% decrease from the 6,033 rabid animals reported in 2014. Of the 5,508 cases of animal rabies, 5,088 (92.4%) involved wildlife. Relative contributions by the major animal groups were as follows: 1,704 (30.9%) bats, 1,619 (29.4%) raccoons, 1,365 (24.8%) skunks, 325 (5.9%) foxes, 244 (4.4%) cats, 85 (1.5%) cattle, and 67 (1.2%) dogs. There was a 4.1% decrease in the number of samples submitted for testing in 2015, compared with the number submitted in 2014. Three human rabies deaths were reported in 2015, compared with only 1 in 2014. A 65-year-old man in Massachusetts was bitten by a rabid dog while abroad. A 77-year-old woman in Wyoming had contact with a bat. A 54-year-old man in Puerto Rico was bitten by a mongoose. The only connection among these 3 cases was that none received postexposure prophylaxis. CONCLUSIONS AND CLINICAL RELEVANCE Laboratory testing of animals suspected to be rabid remains a critical public health function and continues to be a cost-effective method to directly influence human rabies postexposure prophylaxis recommendations. (J Am Vet Med Assoc 2017;250:1117-1130).
Rabies is a fatal zoonotic disease that requires fast, accurate diagnosis to prevent disease in an exposed individual. The current gold standard for post-mortem diagnosis of human and animal rabies ...is the direct fluorescent antibody (DFA) test. While the DFA test has proven sensitive and reliable, it requires high quality antibody conjugates, a skilled technician, a fluorescence microscope and diagnostic specimen of sufficient quality. The LN34 pan-lyssavirus real-time RT-PCR assay represents a strong candidate for rabies post-mortem diagnostics due to its ability to detect RNA across the diverse Lyssavirus genus, its high sensitivity, its potential for use with deteriorated tissues, and its simple, easy to implement design. Here, we present data from a multi-site evaluation of the LN34 assay in 14 laboratories. A total of 2,978 samples (1,049 DFA positive) from Africa, the Americas, Asia, Europe, and the Middle East were tested. The LN34 assay exhibited low variability in repeatability and reproducibility studies and was capable of detecting viral RNA in fresh, frozen, archived, deteriorated and formalin-fixed brain tissue. The LN34 assay displayed high diagnostic specificity (99.68%) and sensitivity (99.90%) when compared to the DFA test, and no DFA positive samples were negative by the LN34 assay. The LN34 assay produced definitive findings for 80 samples that were inconclusive or untestable by DFA; 29 were positive. Five samples were inconclusive by the LN34 assay, and only one sample was inconclusive by both tests. Furthermore, use of the LN34 assay led to the identification of one false negative and 11 false positive DFA results. Together, these results demonstrate the reliability and robustness of the LN34 assay and support a role for the LN34 assay in improving rabies diagnostics and surveillance.
Optimized symptom-based COVID-19 case definitions that guide public health surveillance and individual patient management in the community may assist pandemic control.
We assessed diagnostic ...performance of existing cases definitions (e.g. influenza-like illness, COVID-like illness) using symptoms reported from 185 household contacts to a PCR-confirmed case of COVID-19 in Wisconsin and Utah, United States. We stratified analyses between adults and children. We also constructed novel case definitions for comparison.
Existing COVID-19 case definitions generally showed high sensitivity (86-96%) but low positive predictive value (PPV) (36-49%; F-1 score 52-63) in this community cohort. Top performing novel symptom combinations included taste or smell dysfunction and improved the balance of sensitivity and PPV (F-1 score 78-80). Performance indicators were generally lower for children (< 18 years of age).
Existing COVID-19 case definitions appropriately screened in household contacts with COVID-19. Novel symptom combinations incorporating taste or smell dysfunction as a primary component improved accuracy. Case definitions tailored for children versus adults should be further explored.
Microfluidics technology offers a platform for development of point-of-care diagnostic devices for various infectious diseases. In this study, we examined whether serodiagnosis of Johne's disease ...(JD) can be conducted in a bead-based microfluidic assay system. Magnetic micro-beads were coated with antigens of the causative agent of JD, Mycobacterium avium subsp. paratuberculosis. The antigen-coated beads were incubated with serum samples of JD-positive or negative serum samples and then with a fluorescently-labeled secondary antibody (SAB). To confirm binding of serum antibodies to the antigen, the beads were subjected to flow cytometric analysis. Different conditions (dilutions of serum and SAB, types of SAB, and types of magnetic beads) were optimized for a large degree of differentiation between the JD-negative and JD-positive samples. Using the optimized conditions, we tested a well-classified set of 155 serum samples from JD-negative and JD-positive cattle by using the bead-based flow cytometric assay. Of 105 JD-positive samples, 63 samples (60%) showed higher antibody binding levels than a cut-off value determined by using antibody binding levels of JD-negative samples. In contrast, only 43–49 JD-positive samples showed higher antibody binding levels than the cut-off value when the samples were tested using commercially-available immunoassays. Microfluidic assays were performed by magnetically immobilizing a number of beads within a microchannel of a glass microchip and detecting antibody on the collected beads using laser-induced fluorescence. Antigen-coated magnetic beads treated with the bovine serum sample and fluorescently-labeled SAB were loaded into a microchannel to measure the fluorescence (reflecting level of antibody binding) on the beads in the microfluidic system. When the results of five bovine serum samples with the microfluidic system were compared to those analyzed with the flow cytometer, a high level of correlation (linear regression, r2=0.994) was observed. In a further experiment, we magnetically immobilized antigen-coated beads in a microchannel, reacted the beads with serum and SAB in the channel, and detected antibody binding to the beads in the microfluidic system. A strong antibody binding in JD-positive serum was detected, whereas there was only negligible binding in negative control experiments. Our data suggest that the bead-based microfluidic system may form a basis for development of an on-site serodiagnosis of JD.
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