cAMP regulates the progesterone receptor gene expression through the protein kinase A pathway during decidualization in human immortalized endometrial stromal cells.

Decidualization, a crucial process for successful pregnancy establishment and maintenance, involves endometrial stromal cell differentiation. This process is orchestrated by estradiol (E2), progesterone, and other stimuli that increase intracellular cyclic adenosine monophosphate (cAMP) levels. The intracellular progesterone receptor (PR), encoded by the PGR gene, has a key role in decidualization. This study aimed to understand the role of sex steroids and cAMP in regulating PGR expression during the in vitro decidualization of the human immortalized endometrial stromal cell line, T-HESC. We subjected the cells to individual and combined treatments of E2, medroxyprogesterone (MPA), and cAMP. Additionally, we treated cells with PR and estrogen receptor antagonists and a protein kinase A (PKA) inhibitor. We evaluated the expression of PGR isoforms and decidualization-associated genes by RT-qPCR. Our findings revealed that cAMP induced PGR-B and PGR-AB expression by activating the PKA signaling pathway, while MPA downregulated their expression through the PR. Furthermore, downstream genes involved in decidualization, such as those coding for prolactin (PRL), insulin-like growth factor-binding protein-1 (IGFBP1), and Dickkopf-1 (DKK1), exhibited positive regulation via the cAMP-PKA pathway. Remarkably, MPA-activated PR signaling induced the expression of IGFBP1 and DKK1 but inhibited that of PRL. In conclusion, we have demonstrated that the PKA signaling pathway induces PGR gene expression during in vitro decidualization of the T-HESC human endometrial stromal cell line. This study has unraveled some of the intricate regulatory mechanisms governing PGR expression during this fundamental process for implantation and pregnancy maintenance.

Unilateral lesion of the suprachiasmatic nucleus impairs estradiol feedback, follicular development, estrous cycle and ovulation.

In brief: The SCN regulates ovulation by stimulating the preovulatory surge of gonadotropins. This study revealed an additional role in the sensitization of the hypothalamus to estradiol that changes along the estrous cycle and the side of the nucleus. Abstract: Ovulation is timed by neural signals originating at the suprachiasmatic nucleus (SCN) that trigger ovulation when converge with high estradiol levels, which indicates the maturation of ovarian follicles. We have shown that the hypothalamic regulation of ovulation is asymmetrical and we hypothesized that the paired SCN could contribute to such symmetries. We unilaterally lesioned the SCN of rats at each stage of the estrous cycle and evaluated the acute effects on the progression of their estrous cycle, follicular development and ovulation. Lesions prevented progression of the estrous cycle when performed in estrus/metestrus but not in diestrus/proestrus. Abnormalities in follicular development were observed in the nonovulating lesioned rats and this was independent of the side of the SCN destroyed and the stage of the cycle when surgery was performed. Groups of lesioned rats were then hormonally primed with GnRH or estradiol to assess the neuroendocrine pathway altered by the treatment. GnRH restored ovulation, suggesting that both SCN are needed for proper triggering of the preovulatory surge of GnRH and that unilateral lesion does not impair the sensitivity of the pituitary or the ovary to GnRH and gonadotropins, respectively. With regard to restoring ovulation, estradiol was asymmetrically effective in rats lesioned in estrous, partially effective in rats operated at diestrus and ineffective in rats at metestrus. Our results indicate that the SCN regulates the activity of the hypothalamic-pituitary-ovarian axis not only by modulating the preovulatory surge of GnRH/gonadotropins but also by promoting the hypothalamic integration of estrogenic signals from the ovaries in an asymmetric and stage-dependent fashion.

Index cases first identified by nasal-swab rapid COVID-19 tests had more transmission to household contacts than cases identified by other test types.

At-home rapid COVID-19 tests in the U.S. utilize nasal-swab specimens and require high viral loads to reliably give positive results. Longitudinal studies from the onset of infection have found infectious virus can present in oral specimens days before nasal. Detection and initiation of infection-control practices may therefore be delayed when nasal-swab rapid tests are used, resulting in greater transmission to contacts. We assessed whether index cases first identified by rapid nasal-swab COVID-19 tests had more transmission to household contacts than index cases who used other test types (tests with higher analytical sensitivity and/or non-nasal specimen types). In this observational cohort study, 370 individuals from 85 households with a recent COVID-19 case were screened at least daily by RT-qPCR on one or more self-collected upper-respiratory specimen types. A two-level random intercept model was used to assess the association between the infection outcome of household contacts and each covariable (household size, race/ethnicity, age, vaccination status, viral variant, infection-control practices, and whether a rapid nasal-swab test was used to initially identify the household index case). Transmission was quantified by adjusted secondary attack rates (aSAR) and adjusted odds ratios (aOR). An aSAR of 53.6% (95% CI 38.8-68.3%) was observed among households where the index case first tested positive by a rapid nasal-swab COVID-19 test, which was significantly higher than the aSAR for households where the index case utilized another test type (27.2% 95% CI 19.5-35.0%, P = 0.003 pairwise comparisons of predictive margins). We observed an aOR of 4.90 (95% CI 1.65-14.56) for transmission to household contacts when a nasal-swab rapid test was used to identify the index case, compared to other test types. Use of nasal-swab rapid COVID-19 tests for initial detection of infection and initiation of infection control may be less effective at limiting transmission to household contacts than other test types.

Platinum(II)-Based Optical Probes for Imaging Quadruplex DNA Structures via Phosphorescence Lifetime Imaging Microscopy.

G-quadruplex DNA is a non-canonical structure that forms in guanine-rich regions of the genome. There is increasing evidence showing that G-quadruplexes have important biological functions, and therefore molecular tools to visualise these structures are important. Herein we report on a series of new cyclometallated platinum(II) complexes which, upon binding to G-quadruplex DNA, display an increase in their phosphorescence, acting as switch-on probes. More importantly, upon binding to G-quadruplexes they display a selective and distinct lengthening of their emission lifetime. We show that this effect can be used to selectively visualise these structures in cells using Phosphorescence Lifetime Imaging Microscopy (PLIM).

Association of a sepsis initiative on broad spectrum antibiotic use and outcomes in an ED population.

INTRODUCTION: Sepsis identification and treatment is a priority for emergency department (ED) providers and payors alike. However, aggressive metrics aimed at improving sepsis care could have unintended consequences for patients who do not have sepsis. METHODS: All ED patient visits for a one month period before and after a quality initiative to increase early antibiotic use in septic patients were included. Overall broad spectrum (BS) antibiotic use, admission rates, and mortality were compared in the 2 time periods. A more detailed chart review was performed on those who received BS antibiotics in the before and after cohorts. Patient were excluded for pregnancy, age < 18, COVID-19 infection, hospice patients, left ED against medical advice, and if antibiotics were given for prophylaxis. In BS antibiotic treated patients, we sought to determine mortality, rates of subsequent multidrug resistant (MDR) or Clostridium Difficile (CDiff) infections and rates of non-infected patients receiving BS antibiotics. RESULTS: There were 7967 and 7407 ED visits in the pre- and post-implementation periods, respectively. Of those, BS antibiotics were administered in a total of 3.9% pre-implementation and 6.2% post-implementation (p ≤ 0.00001). Admission was more common in the post-implementation period, but overall mortality was unchanged (0.9% pre-implementation and 0.8% post-implementation, p = 0.41). After exclusions, 654 patients treated with BS antibiotics were included in the secondary analyses. Baseline characteristics were similar between the pre-implementation and post-implementation cohorts. There was no difference in the rate of CDiff infection or the proportion of patients receiving BS antibiotics who were not infected, but there was an increase in the post-implementation period in MDR infections after ED BS antibiotics, 0.72% vs. 0.35% of the entire ED cohorts, p = 0.0009. CONCLUSIONS: We found that a QI sepsis initiative was associated with an increase in the proportion of patients who received BS antibiotics in the ED, and a small absolute increase in associated subsequent MDR infections, with no apparent effect on mortality in all ED patients or the subset treated with BS antibiotics. Further research is needed to assess the impact on all patients affected by aggressive sepsis protocols and initiatives, rather than only those with sepsis.

Rhabdomyolysis After Intravenous Iron Sucrose Infusion During Pregnancy.

BACKGROUND: Iron infusions have become increasingly common in the treatment of iron-deficiency anemia during pregnancy. Although iron infusions are generally well tolerated, adverse reactions have been reported. CASE: A pregnant patient was diagnosed with rhabdomyolysis after receiving a second dose of intravenous (IV) iron sucrose at 32 6/7 weeks of gestation. On admission to the hospital, creatine kinase was 2,437 units/L, sodium was 132 mEq/L, and potassium was 2.1 mEq/L. Intravenous fluids and electrolyte repletion were administered, with improvement of symptoms within 48 hours. Creatinine kinase normalized 1 week after hospital discharge. CONCLUSION: Rhabdomyolysis can be associated with IV iron infusion during pregnancy.

Surgeons' Perspectives on Valve Surgery in People With Drug Use-Associated Infective Endocarditis.

BACKGROUND: Hospitalizations for drug-use associated infective endocarditis (DUA-IE) have led to increasing surgical consultation for valve replacement. Cardiothoracic surgeons' perspectives about the process of decision making around operation for people with DUA-IE are largely unknown. METHODS: This multisite semiqualitative study sought to gather the perspectives of cardiothoracic surgeons on initial and repeat valve surgery for people with DUA-IE through purposeful sampling of surgeons at 7 hospitals: University of Alabama, Tufts Medical Center, Boston Medical Center, Massachusetts General Hospital, University of North Carolina-Chapel Hill, Vanderbilt University Medical Center, and Rhode Island Hospital-Brown University. RESULTS: Nineteen cardiothoracic surgeons (53% acceptance) were interviewed. Perceptions of the drivers of addiction varied as well as approaches to repeat valve operations. There were mixed views on multidisciplinary meetings, although many surgeons expressed an interest in more efficient meetings and more intensive postoperative and posthospitalization multidisciplinary care. CONCLUSIONS: Cardiothoracic surgeons are emotionally and professionally impacted by making decisions about whether to perform valve operation for people with DUA-IE. The use of efficient, agenda-based multidisciplinary care teams is an actionable solution to improve cross-disciplinary partnerships and outcomes for people with DUA-IE.

Platinum(II)-Based Optical Probes for Imaging Quadruplex DNA Structures via Phosphorescence Lifetime Imaging Microscopy.

G-quadruplex DNA is a non-canonical structure that forms in guanine-rich regions of the genome. There is increasing evidence showing that G-quadruplexes have important biological functions, and therefore molecular tools to visualise these structures are important. Herein we report on a series of new cyclometallated platinum(II) complexes which, upon binding to G-quadruplex DNA, display an increase in their phosphorescence, acting as switch-on probes. More importantly, upon binding to G-quadruplexes they display a selective and distinct lengthening of their emission lifetime. We show that this effect can be used to selectively visualise these structures in cells using Phosphorescence Lifetime Imaging Microscopy (PLIM).

Morning SARS-CoV-2 Testing Yields Better Detection of Infection Due to Higher Viral Loads in Saliva and Nasal Swabs upon Waking.

Optimizing specimen collection methods to achieve the most reliable SARS-CoV-2 detection for a given diagnostic sensitivity would improve testing and minimize COVID-19 outbreaks. From September 2020 to April 2021, we performed a household-transmission study in which participants self-collected specimens every morning and evening throughout acute SARS-CoV-2 infection. Seventy mildly symptomatic participants collected saliva, and of those, 29 also collected nasal swab specimens. Viral load was quantified in 1,194 saliva and 661 nasal swab specimens using a high-analytical-sensitivity reverse transcription-quantitative PCR (RT-qPCR) assay. Viral loads in both saliva and nasal swab specimens were significantly higher in morning-collected specimens than in evening-collected specimens after symptom onset. This aspect of the biology of SARS-CoV-2 infection has implications for diagnostic testing. We infer that morning collection would have resulted in significantly improved detection and that this advantage would be most pronounced for tests with low to moderate analytical sensitivity. Collecting specimens for COVID-19 testing in the morning offers a simple and low-cost improvement to clinical diagnostic sensitivity of low- to moderate-analytical-sensitivity tests. IMPORTANCE Our findings suggest that collecting saliva and nasal swab specimens in the morning immediately after waking yields higher SARS-CoV-2 viral loads than collection later in the day. The higher viral loads from morning specimen collection are predicted to significantly improve detection of SARS-CoV-2 in symptomatic individuals, particularly when using moderate- to low-analytical-sensitivity COVID-19 diagnostic tests, such as rapid antigen tests.

Changes in OGTT-derived biomarkers in response to lifestyle intervention among Latino adolescents with obesity.

BACKGROUND: Glucose concentrations during an oral glucose tolerance test (OGTT) have been used as biomarkers to differentiate type 2 diabetes risk phenotypes. No studies have examined changes in OGTT-glucose phenotypes following lifestyle intervention among high-risk youth. OBJECTIVE: To examine changes in OGTT-glucose phenotypes following lifestyle intervention and to explore differences in insulin sensitivity and ß-cell function among post-intervention phenotypes. METHODS: Latino adolescents with obesity (n = 48, age 15.4 ± 1.0, BMI% 98.2 ± 1.4, female 56.3%) completed a 12-week lifestyle intervention that included weekly nutrition education and physical activity. At baseline and 12 weeks, youth completed a 2-h OGTT with glucose and insulin concentrations assessed at 0', 30', 60', 90' and 120'. Glucose concentrations during the OGTT were used to identify biomarkers, 1-h glucose, glucose response curve and time to glucose peak. Using these respective biomarkers, high-risk (1-h glucose ≥ 155 mg/dl, Monophasic, Late Peak) and lower-risk phenotypes (1-h glucose < 155 mg/dl, Biphasic, Early Peak) were categorized. Insulin sensitivity was estimated by whole-body insulin sensitivity index (WBISI) and ß-cell function by oral disposition index (oDI). RESULTS: Following intervention, the prevalence of Monophasic phenotypes decreased from 81% to 67% (p = 0.048) and 1-h glucose ≥ 155 mg/dl from 38% to 10% (p = 0.054). Although Late Peak phenotypes did not significantly change (from 58% to 29%, p = 0.200), Early Peak phenotypes at post-intervention demonstrated significantly higher WBISI compared to Late Peak (2.3 ± 0.1 vs 1.7 ± 0.2, p = 0.023). CONCLUSIONS: OGTT-glucose phenotypes improve following lifestyle intervention among high-risk youth. These findings further support their potential utility as clinical biomarkers to identify diabetes risk and risk reduction in youth.

Quantitative SARS-CoV-2 Viral-Load Curves in Paired Saliva Samples and Nasal Swabs Inform Appropriate Respiratory Sampling Site and Analytical Test Sensitivity Required for Earliest Viral Detection.

Early detection of SARS-CoV-2 infection is critical to reduce asymptomatic and presymptomatic transmission, curb the spread of variants, and maximize treatment efficacy. Low-analytical-sensitivity nasal-swab testing is commonly used for surveillance and symptomatic testing, but the ability of these tests to detect the earliest stages of infection has not been established. In this study, conducted between September 2020 and June 2021 in the greater Los Angeles County, California, area, initially SARS-CoV-2-negative household contacts of individuals diagnosed with COVID-19 prospectively self-collected paired anterior-nares nasal-swab and saliva samples twice daily for viral-load quantification by high-sensitivity reverse-transcription quantitative PCR (RT-qPCR) and digital-RT-PCR assays. We captured viral-load profiles from the incidence of infection for seven individuals and compared diagnostic sensitivities between respiratory sites. Among unvaccinated persons, testing saliva with a high-analytical-sensitivity assay detected infection up to 4.5 days before viral loads in nasal swabs reached concentrations detectable by low-analytical-sensitivity nasal-swab tests. For most participants, nasal swabs reached higher peak viral loads than saliva but were undetectable or at lower loads during the first few days of infection. High-analytical-sensitivity saliva testing was most reliable for earliest detection. Our study illustrates the value of acquiring early (within hours after a negative high-sensitivity test) viral-load profiles to guide the appropriate analytical sensitivity and respiratory site for detecting earliest infections. Such data are challenging to acquire but critical to designing optimal testing strategies with emerging variants in the current pandemic and to respond to future viral pandemics.

Heterogeneity in Jail Nursing Medical Intake Forms: A Content Analysis.

Despite high prevalence of infectious diseases and substance use disorders in jails, there are limited guidelines for the nursing intake process in this setting. We performed a content analysis of nursing intake forms used at each of the 14 Massachusetts county jails, focusing on infectious disease and substance use disorder. Only 85% of jails offered HIV testing during nursing intake and 50% of jails offered hepatitis C testing. Preventive interventions such as vaccines or pre-exposure prophylaxis therapy were infrequently offered during nursing intake. Screening for substance use disorder was present on the majority of intake forms, but only 23% of intake forms inquired about ongoing medication-assisted treatment for opioid use disorder. The results reflect heterogeneity in nursing intake forms, highlighting missed opportunities for public health interventions.

Differential localization of serotoninergic system elements in human amniotic epithelial cells†.

Serotonin or 5-hydroxytryptamine (5-HT) is a biogenic amine involved in regulating several functions, including development. However, its impact on human embryo development has been poorly studied. The present work investigated the expression and distribution of the main components of the serotoninergic system in human amniotic tissue and human amniotic epithelial cells (hAEC) in vitro, as an alternative model of early human embryo development. Amniotic membranes from full-term healthy pregnancies were used. Human amnion tissue or hAEC isolated from the amnion was processed for reverse transcription-polymerase chain reaction and immunofluorescence analyses of the main components of the serotoninergic system. We found the expression of tryptophan hydroxylase type 1 (TPH1), type 2 (TPH2), serotonin transporter (SERT), monoamine oxidase-A (MAOA), as well as HTR1D and HTR7 receptors at mRNA level in amnion tissue as well in hAEC. Interestingly, we found the presence of 5-HT in the nucleus of the cells in amnion tissue, whereas it was located in the cytoplasm of isolated hAEC. We detected TPH1, TPH2, and HTR1D receptor in both the nucleus and cytoplasm. SERT, MAOA, and HTR7 receptor were only observed in the cytoplasm. The results presented herein show, for the first time, the presence of the serotoninergic system in human amnion in vivo and in vitro.

"I'm not gonna be able to do anything about it, then what's the point?": A broad group of stakeholders identify barriers and facilitators to HCV testing in a Massachusetts jail.

BACKGROUND: Despite national guidelines promoting hepatitis C virus (HCV) testing in prisons, there is substantial heterogeneity on the implementation of HCV testing in jails. We sought to better understand barriers and opportunities for HCV testing by interviewing a broad group of stakeholders involved in HCV testing and treatment policies and procedures in Massachusetts jails. METHODS: We conducted semi-structured interviews with people incarcerated in Middlesex County Jail (North Billerica, MA), clinicians working in jail and community settings, corrections administrators, and representatives from public health, government, and industry between November 2018-April 2019. RESULTS: 51/120 (42%) of people agreed to be interviewed including 21 incarcerated men (mean age 32 [IQR 25, 39], 60% non-White). Themes that emerged from these interviews included gaps in knowledge about HCV testing and treatment opportunities in jail, the impact of captivity and transience, and interest in improving linkage to HCV care after release. Many stakeholders discussed stigma around HCV infection as a factor in reluctance to provide HCV testing or treatment in the jail setting. Some stakeholders expressed that stigma often led decisionmakers to estimate a lower "worth" of incarcerated individuals living with HCV and therefore to decide against paying for HCV testing.". CONCLUSION: All stakeholders agreed that HCV in the jail setting is a public health issue that needs to be addressed. Exploring stakeholders' many ideas about how HCV testing and treatment can be approached is the first step in developing feasible and acceptable strategies.

Quantitative SARS-CoV-2 viral-load curves in paired saliva and nasal swabs inform appropriate respiratory sampling site and analytical test sensitivity required for earliest viral detection.

Early detection of SARS-CoV-2 infection is critical to reduce asymptomatic and pre-symptomatic transmission, curb the spread of variants by travelers, and maximize treatment efficacy. Low-sensitivity nasal-swab testing (antigen and some nucleic-acid-amplification tests) is commonly used for surveillance and symptomatic testing, but the ability of low-sensitivity nasal-swab tests to detect the earliest stages of infection has not been established. In this case-ascertained study, initially-SARS-CoV-2-negative household contacts of individuals diagnosed with COVID-19 prospectively self-collected paired anterior-nares nasal-swab and saliva samples twice daily for viral-load quantification by high-sensitivity RT-qPCR and digital-RT-PCR assays. We captured viral-load profiles from the incidence of infection for seven individuals and compared diagnostic sensitivities between respiratory sites. Among unvaccinated persons, high-sensitivity saliva testing detected infection up to 4.5 days before viral loads in nasal swabs reached the limit of detection of low-sensitivity nasal-swab tests. For most participants, nasal swabs reached higher peak viral loads than saliva, but were undetectable or at lower loads during the first few days of infection. High-sensitivity saliva testing was most reliable for earliest detection. Our study illustrates the value of acquiring early (within hours after a negative high-sensitivity test) viral-load profiles to guide the appropriate analytical sensitivity and respiratory site for detecting earliest infections. Such data are challenging to acquire but critical to design optimal testing strategies in the current pandemic and will be required for responding to future viral pandemics. As new variants and viruses emerge, up-to-date data on viral kinetics are necessary to adjust testing strategies for reliable early detection of infections.

Metal complexes as optical probes for DNA sensing and imaging.

Transition and lanthanide metal complexes have rich photophysical properties that can be used for cellular imaging, biosensing and phototherapy. One of the applications of such luminescent compounds is the detection and visualisation of nucleic acids. In this brief review, we survey the recent literature on the use of luminescent metal complexes (including ReI, RuII, OsII, IrIII, PtII, EuIII and TbIII) as DNA optical probes, including examples of compounds that bind selectively to non-duplex DNA topologies such as quadruplex, i-motif and DNA mismatches. We discuss the applications of metal-based luminescent complexes in cellular imaging, including time-resolved microscopy and super-resolution techniques. Their applications in biosensing and phototherapy are briefly mentioned in the relevant sections.

The influence of exercise intensity and exercise mode on gastrointestinal damage.

Strenuous exercise increases gastrointestinal damage, but the dose-response relationship is yet to be elucidated. It is also commonly believed that running causes greater gastrointestinal damage than cycling. Two randomised, crossover studies aimed to 1) quantify gastrointestinal damage with increasing exercise intensity, and 2) determine if running was associated with greater gastrointestinal damage than cycling. Following a maximal oxygen uptake (V̇O2max) test, participants completed 3 cycling trials at different intensities (60 min at 40%, 60% and 80% V̇O2max; n = 10 (5 female, 5 male)) (INTENSITY), or 1 running and 1 cycling trial (45 min at 70% V̇O2max; n = 11 (3 female, 8 male)) (MODE). Venous blood samples were collected pre- and post-exercise to measure gastrointestinal damage via intestinal fatty acid binding protein (I-FABP). In INTENSITY, I-FABP magnitude of change was greater at 80% V̇O2max than 40% V̇O2max (p < 0.01). In MODE, I-FABP magnitude of change was greater with cycling (mean (SD)) (84.7 (133.2)% d = 1.07) compared with running (19.3 (33.1)%, d = 0.65) with a moderate effect (d = 0.68, p = 0.024). Rating of perceived exertion (RPE) and heart rate (HR) were higher during cycling (RPE p < 0.0001; HR p < 0.0001) but rectal temperature was not different between modes (p = 0.94). While gastrointestinal damage increases with increasing exercise intensity, running was not associated with greater gastrointestinal damage than cycling. Novelty: A fraction of the anaerobic threshold, rather than a fraction of V̇O2max, may be more predictive of intensity that results in exercise induced gastrointestinal damage. The mode of exercise may not be as important as intensity for inducing gastrointestinal damage. Improving anaerobic threshold may reduce susceptibility to gastrointestinal damage when exercising at high intensities.

Role of serotonin in vertebrate embryo development.

Since its discovery in 1937, serotonin (5-HT) has become one of the most studied biogenic amines due to its predominant role in regulating several physiological processes such as mood, sleep, and food intake. This amine and the main components of the serotoninergic system are in almost all cells of the body. The presence of 5-HT and the serotoninergic system has been observed in oocytes and in different embryo development stages of fish, amphibians, birds, and mammals. In several classes of vertebrates, the change in the concentration of 5-HT or the alteration of the serotoninergic system, interfere with early embryo development. These data suggest that 5-HT participates in embryo development of vertebrates.

SARS-CoV-2 Viral Load in Saliva Rises Gradually and to Moderate Levels in Some Humans.

Transmission of SARS-CoV-2 in community settings often occurs before symptom onset, therefore testing strategies that can reliably detect people in the early phase of infection are urgently needed. Early detection of SARS-CoV-2 infection is especially critical to protect vulnerable populations who require frequent interactions with caretakers. Rapid COVID-19 tests have been proposed as an attractive strategy for surveillance, however a limitation of most rapid tests is their low sensitivity. Low-sensitivity tests are comparable to high sensitivity tests in detecting early infections when two assumptions are met: (1) viral load rises quickly (within hours) after infection and (2) viral load reaches and sustains high levels (>105-106 RNA copies/mL). However, there are no human data testing these assumptions. In this study, we document a case of presymptomatic household transmission from a healthy young adult to a sibling and a parent. Participants prospectively provided twice-daily saliva samples. Samples were analyzed by RT-qPCR and RT-ddPCR and we measured the complete viral load profiles throughout the course of infection of the sibling and parent. This study provides evidence that in at least some human cases of SARS-CoV-2, viral load rises slowly (over days, not hours) and not to such high levels to be detectable reliably by any low-sensitivity test. Additional viral load profiles from different samples types across a broad demographic must be obtained to describe the early phase of infection and determine which testing strategies will be most effective for identifying SARS-CoV-2 infection before transmission can occur.

Efficacy assessment of commercially available natural products and antibiotics, commonly used for mitigation of pathogenic Vibrio outbreaks in Ecuadorian Penaeus (Litopenaeus) vannamei hatcheries.

Bacterial diseases cause high mortality in Penaeus (Litopenaeus) vannamei postlarvae. Therefore, appropriate application of efficient therapeutic products is of vital importance for disease control. This study evaluated through in vitro analyses the antimicrobial effectiveness of commercial therapeutic products used for P. vannamei bacterial diseases and antibiotics against pathogenic Vibrio strains circulating in Ecuadorian hatcheries. Twenty strains were isolated from 31 larvae samples with high bacterial counts from 10 hatcheries collected during mortality events. The strains virulence was verified through challenge tests with Artemia franciscana nauplii and P. vannamei postlarvae. Through 16S rRNA sequence analysis, strains showed a great similarity to the Vibrio sequences reported as pathogens, with 95% belonging to the Harveyi clade. Through antibiograms and minimal inhibitory concentration (MIC) in vitro tests we found that furazolidone, ciprofloxacin, chloramphenicol, norfloxacin, nalidixic acid, florfenicol, fosfomycin and enrofloxacin inhibited the growth of all or most of the strains. Less efficient antibiotics were penicillin, oxytetracycline and tetracycline. A multiple antibiotic resistance (MAR) index of 0.23 showed some level of resistance to antibiotics, with two MAR prevalent patterns (Penicillin-Oxytetracycline and Penicillin-Oxytetracycline-Tetracycline). From a total of 16 natural products (five probiotics, nine organic acids and two essential oils), only three (one probiotic, one organic acid and one essential oil) were effective to control most of the strains. Shrimp producers can apply relatively simple in vitro analyses, such as those employed in this study, to help take adequate management decisions to reduce the impact of bacterial diseases and increase profit.