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Frontiers in Cellular and Infection... 2018Human Immunodeficiency Virus (HIV) co-infection drastically increases the risk of developing overt visceral leishmaniasis (VL). The asymptomatic infection window...
Human Immunodeficiency Virus (HIV) co-infection drastically increases the risk of developing overt visceral leishmaniasis (VL). The asymptomatic infection window constitutes an opportunity to identify those HIV patients at highest risk by defining early markers associated with disease susceptibility or resistance. As intracellular parasite killing is essential, we investigated whether serum markers of macrophage activation were notably affected in HIV patients with an asymptomatic infection or overt visceral leishmaniasis disease. Serum levels of soluble CD40 ligand and neopterin were assessed in 24 active VL-HIV patients, 35 HIV patients with asymptomatic infection and 35 HIV endemic controls. All patients were recruited in endemic regions of North-West Ethiopia. The serum levels of sCD40L and neopterin significantly decreased and increased in HIV patients with active VL compared to HIV patients with asymptomatic infection, respectively. No statistically significant differences could be detected in neopterin and sCD40L levels between asymptomatically infected HIV patients and endemic HIV control patients. However, an inverse trend, between antibody positivity or VL development and neopterin levels could be seen. The CD4+ T-cell count was inversely correlated with serum neopterin levels, but not with sCD40L levels. Our results in HIV coinfected patients, correspond with the postulated protective role of sCD40L in VL and underline the importance of the CD40-CD40L pathway in resistance against the parasite. Neopterin levels suggest an increased macrophage activation upon infection and could have a value in clinical algorithms to, although non-specifically, improve prediction of VL development in HIV patients with asymptomatic infection.
Topics: Adolescent; Adult; Asymptomatic Infections; Biomarkers; CD40 Ligand; Cohort Studies; Coinfection; Female; HIV Infections; Humans; Leishmania donovani; Leishmaniasis, Visceral; Male; Middle Aged; Neopterin; Young Adult
PubMed: 30619775
DOI: 10.3389/fcimb.2018.00428 -
Nature Reviews. Microbiology Nov 2012Toxoplasma gondii is a common parasite of animals and humans and can cause serious opportunistic infections. However, the majority of infections are asymptomatic,... (Review)
Review
Toxoplasma gondii is a common parasite of animals and humans and can cause serious opportunistic infections. However, the majority of infections are asymptomatic, possibly because the organism has co-evolved with its many vertebrate hosts and has developed multiple strategies to persist asymptomatically for the lifetime of the host. Over the past two decades, infection studies in the mouse, combined with forward-genetics approaches aimed at unravelling the molecular basis of infection, have revealed that T. gondii virulence is mediated, in part, by secretion of effector proteins into the host cell during invasion. Here, we review recent advances that illustrate how these virulence factors disarm innate immunity and promote survival of the parasite.
Topics: Animals; Animals, Domestic; Cats; Host-Parasite Interactions; Humans; Immune Evasion; Immunity, Innate; Mice; Protein-Tyrosine Kinases; Protozoan Proteins; Signal Transduction; Toxoplasma; Toxoplasmosis; Toxoplasmosis, Animal; Virulence Factors
PubMed: 23070557
DOI: 10.1038/nrmicro2858 -
Europace : European Pacing,... Sep 2008Recent work has been focused on causes of and risk factors for rhythm management device infections. The aim of this study was to elucidate whether patients may be...
AIMS
Recent work has been focused on causes of and risk factors for rhythm management device infections. The aim of this study was to elucidate whether patients may be asymptomatic carriers of bacteria on their rhythm management device, possibly allowing later manifestation of infection.
METHODS AND RESULTS
A total of 108 devices were changed for battery depletion between April 2005 and February 2006 in asymptomatic patients who were examined for evidence of bacterial DNA on the device and in the surrounding tissue using single strand conformation polymorphism analysis (SSCP). Follow-up was for 23.4 months. In 47.2% of the patients, bacterial DNA was demonstrated on the device, which had been in place for 64.1 months. The sequences identified bacterial strains that are untypical for clinical device infections. Staphylococci were demonstrated in only 3.7% of the patients and they became symptomatic within the observation interval; all others remained asymptomatic. The known risk factors for device infections did not correlate with the demonstration of bacterial DNA in this population. Common cohabitation was identified among the strains found.
CONCLUSION
A large proportion of patients carry bacteria on their pacemaker or implantable cardioverter defibrillator asymptomatically. The strains found differ from those commonly seen in clinically evident device infections. Common risk factors for device infection did not correlate with the presence of DNA.
Topics: Adolescent; Adult; Aged; Aged, 80 and over; Bacterial Infections; Defibrillators, Implantable; Female; Germany; Humans; Male; Middle Aged; Myocarditis; Pacemaker, Artificial; Prevalence; Prosthesis-Related Infections; Risk Assessment; Risk Factors
PubMed: 18658253
DOI: 10.1093/europace/eun191 -
BMC Public Health Nov 2020Mathematical modelling of infectious diseases is a powerful tool for the design of management policies and a fundamental part of the arsenal currently deployed to deal...
BACKGROUND
Mathematical modelling of infectious diseases is a powerful tool for the design of management policies and a fundamental part of the arsenal currently deployed to deal with the COVID-19 pandemic.
METHODS
We present a compartmental model for the disease where symptomatic and asymptomatic individuals move separately. We introduced healthcare burden parameters allowing to infer possible containment and suppression strategies. In addition, the model was scaled up to describe different interconnected areas, giving the possibility to trigger regionalized measures. It was specially adjusted to Mendoza-Argentina's parameters, but is easily adaptable for elsewhere.
RESULTS
Overall, the simulations we carried out were notably more effective when mitigation measures were not relaxed in between the suppressive actions. Since asymptomatics or very mildly affected patients are the vast majority, we studied the impact of detecting and isolating them. The removal of asymptomatics from the infectious pool remarkably lowered the effective reproduction number, healthcare burden and overall fatality. Furthermore, different suppression triggers regarding ICU occupancy were attempted. The best scenario was found to be the combination of ICU occupancy triggers (on: 50%, off: 30%) with the detection and isolation of asymptomatic individuals. In the ideal assumption that 45% of the asymptomatics could be detected and isolated, there would be no need for complete lockdown, and Mendoza's healthcare system would not collapse.
CONCLUSIONS
Our model and its analysis inform that the detection and isolation of all infected individuals, without leaving aside the asymptomatic group is the key to surpass this pandemic.
Topics: Argentina; Asymptomatic Infections; COVID-19; Coronavirus Infections; Epidemics; Humans; Models, Theoretical; Pandemics; Patient Isolation; Pneumonia, Viral
PubMed: 33246432
DOI: 10.1186/s12889-020-09843-7 -
Journal of Sport Rehabilitation Aug 2012Achilles tendon rupture is often the result of a long-term degenerative process, frequently occurring asymptomatically.
CONTEXT
Achilles tendon rupture is often the result of a long-term degenerative process, frequently occurring asymptomatically.
OBJECTIVE
To determine the prevalence of asymptomatic Achilles tendinopathy in an active, asymptomatic, young-adult population and to compare these findings across gender.
DESIGN
Convenience sample, cohort study.
SETTING
Research laboratory
PARTICIPANTS
A sample of 52 (28 male, 24 female) healthy, active subjects were recruited from the student body at the University of Connecticut. Images of 104 Achilles tendons were made.
INTERVENTION
Ultrasound images made with a Phillips HD11 with a 15-MHz real-time linear-array transducer were collected on both the longitudinal and transverse axes of the Achilles tendon. Activity level was measured with the International Physical Activity Questionnaire Short Form (IPAQ-SF).
MAIN OUTCOME MEASURE
Presence of ultrasound evidence of Achilles tendinopathy as agreed on by 2 blinded assessors highly skilled in ultrasonography.
RESULTS
More subjects were categorized as highly active (57.4%) on the IPAQ-SF than moderately active (42.6%). One female and one male subject were found to have ultrasound evidence of asymptomatic Achilles tendinopathy, equaling 3.8% prevalence in this study.
CONCLUSION
We found a low prevalence of asymptomatic Achilles tendinopathy in an active, young-adult population. Further work is necessary to identify an optimal group warranting ultrasound screening for asymptomatic tendinopathy.
Topics: Achilles Tendon; Adult; Female; Humans; Male; Prevalence; Surveys and Questionnaires; Tendinopathy; Ultrasonography; Young Adult
PubMed: 22894979
DOI: 10.1123/jsr.21.3.249 -
Journal of Clinical Microbiology Feb 2017Recent evidence shows that patients asymptomatically colonized with Clostridium difficile may contribute to the transmission of C. difficile in health care facilities.... (Comparative Study)
Comparative Study
Recent evidence shows that patients asymptomatically colonized with Clostridium difficile may contribute to the transmission of C. difficile in health care facilities. Additionally, these patients may have a higher risk of developing C. difficile infection. The aim of this study was to compare a commercially available PCR directed to both toxin A and B (artus C. difficile QS-RGQ kit CE; Qiagen), an enzyme-linked fluorescent assay to glutamate dehydrogenase (GDH ELFA) (Vidas, bioMérieux), and an in-house-developed PCR to tcdB, with (toxigenic) culture of C. difficile as the gold standard to detect asymptomatic colonization. Test performances were evaluated in a collection of 765 stool samples obtained from asymptomatic patients at admission to the hospital. The C. difficile prevalence in this collection was 5.1%, and 3.1% contained toxigenic C. difficile Compared to C. difficile culture, the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of the C. difficile GDH ELFA were 87.2%, 91.2%, 34.7%, and 99.3%, respectively. Compared with results of toxigenic culture, the sensitivity, specificity, PPV, and NPV of the commercially available PCR and the in-house PCR were 95.8%, 93.4%, 31.9%, 99.9%, and 87.5%, 98.8%, 70%, and 99.6%, respectively. We conclude that in a low-prevalence setting of asymptomatically colonized patients, both GDH ELFA and a nucleic acid amplification test can be applied as a first screening test, as they both display a high NPV. However, the low PPV of the tests hinders the use of these assays as stand-alone tests.
Topics: Bacterial Proteins; Bacterial Toxins; Bacteriological Techniques; Carrier State; Clostridioides difficile; Clostridium Infections; Enterotoxins; Feces; Hospitals; Humans; Immunoassay; Polymerase Chain Reaction; Predictive Value of Tests; Sensitivity and Specificity
PubMed: 27852676
DOI: 10.1128/JCM.01858-16 -
Research and Practice in Thrombosis and... Mar 2024Managing central venous catheters in patients with neoplasms is challenging, and peripherally inserted central catheter PORT (PICC-PORT) has emerged as a promising...
Incidence and clinical progression of asymptomatic peripherally inserted central catheterrelated thrombosis in solid neoplasm patients: ultrasound insights from a prospective cohort study.
BACKGROUND
Managing central venous catheters in patients with neoplasms is challenging, and peripherally inserted central catheter PORT (PICC-PORT) has emerged as a promising option for safety and efficacy. However, understanding the clinical progression of catheter-related thrombosis (CRT) in cancer patients with central venous catheters remains limited, especially in certain neoplasm types associated with a higher risk of venous thrombosis.
OBJECTIVES
This study aims to assess the effectiveness of ultrasound-guided management in detecting and treating asymptomatic CRT in cancer patients with PICC.
METHODS
In this prospective cohort study of 120 patients with solid neoplasms receiving chemotherapy, we investigated the incidence of isolated upper-extremity superficial vein thrombosis, upper-extremity deep vein thrombosis, and fibrin sheath formation through ultrasound follow-up at 30 and 90 days after catheter insertion. We analyzed risk factors associated with CRT and compared incidence rates between PICC-PORT and traditional PICC.
RESULTS
Among the cohort, 69 patients (57.5%) had high-risk thromboembolic neoplasm, and 31 cases (25.8%) of CRT were observed, mostly within 30 days, with only 7 cases (22.6%) showing symptoms. Traditional PICC use (odds ratio, 5.86; 95% CI, 1.14-30) and high-risk thromboembolic neoplasm (odds ratio, 4.46; 95% CI, 1.26-15.81) were identified as independent risk factors for CRT.
CONCLUSION
The majority of CRT present asymptomatically within the first 30 days of venous catheter insertion in patients with solid neoplasms. Ultrasound follow-up is valuable for detecting asymptomatic CRT. The risk of CRT was lower with PICC-PORT than with PICC. Additionally, the risk of CRT was found to be higher in patients with high-risk thromboembolic neoplasms. It is crucial for larger studies to confirm the utility of treating asymptomatic thromboses and isolated superficial thrombosis.
PubMed: 38660454
DOI: 10.1016/j.rpth.2024.102391 -
American Journal of Infection Control Aug 2015We estimated the status of norovirus infection and prevention in kindergartens and primary schools and identified poor areas for which future education is needed. We...
Norovirus prevention and the prevalence of asymptomatic norovirus infection in kindergartens and primary schools in Changzhou, China: Status of the knowledge, attitudes, behaviors, and requirements.
BACKGROUND
We estimated the status of norovirus infection and prevention in kindergartens and primary schools and identified poor areas for which future education is needed. We evaluated the knowledge, attitude, behavior, requirements of outbreak prevention, and rate of asymptomatic carriers.
METHODS
Two self-administered questionnaires were conducted for data collection. Five hundred seventy-four teachers from kindergartens and primary schools and 3,114 students from primary schools in Changzhou city were sampled for questionnaire investigation. In addition, 511 rectal swabs from healthy children were taken for norovirus detection.
RESULTS
Twenty-one of 511 children were asymptomatically infected with norovirus. The rate of asymptomatic norovirus infection children in kindergartens was 2.7% and 4.7% in primary schools. Nineteen of 21 positive samples were GII strains, the other 2 were GI strains. In addition, we found that primary schools were less prepared to prevent norovirus outbreaks than kindergartens. Settings in the suburban counties needed more education on norovirus prevention.
CONCLUSIONS
The results of this study emphasize the need for training of primary schools and suburban schools about norovirus prevention. Asymptomatic norovirus infection should receive more attention.
Topics: Adult; Aged; Asymptomatic Diseases; Caliciviridae Infections; Child Day Care Centers; Child, Preschool; China; Disease Transmission, Infectious; Female; Health Knowledge, Attitudes, Practice; Humans; Infection Control; Male; Middle Aged; Norovirus; Prevalence; Schools; Surveys and Questionnaires; Young Adult
PubMed: 26026827
DOI: 10.1016/j.ajic.2015.04.182 -
Cell Sep 2018Pathogen virulence exists on a continuum. The strategies that drive symptomatic or asymptomatic infections remain largely unknown. We took advantage of the concept of...
Pathogen virulence exists on a continuum. The strategies that drive symptomatic or asymptomatic infections remain largely unknown. We took advantage of the concept of lethal dose 50 (LD50) to ask which component of individual non-genetic variation between hosts defines whether they survive or succumb to infection. Using the enteric pathogen Citrobacter, we found no difference in pathogen burdens between healthy and symptomatic populations. Iron metabolism-related genes were induced in asymptomatic hosts compared to symptomatic or naive mice. Dietary iron conferred complete protection without influencing pathogen burdens, even at 1000× the lethal dose of Citrobacter. Dietary iron induced insulin resistance, increasing glucose levels in the intestine that were necessary and sufficient to suppress pathogen virulence. A short course of dietary iron drove the selection of attenuated Citrobacter strains that can transmit and asymptomatically colonize naive hosts, demonstrating that environmental factors and cooperative metabolic strategies can drive conversion of pathogens toward commensalism.
Topics: Animals; Asymptomatic Infections; Citrobacter rodentium; Colitis; Colon; Dietary Supplements; Enterobacteriaceae Infections; Female; Host-Pathogen Interactions; Insulin Resistance; Intestine, Small; Iron; Lethal Dose 50; Male; Mice; Mice, Inbred C3H; Mice, Inbred DBA; Virulence
PubMed: 30100182
DOI: 10.1016/j.cell.2018.07.016 -
Journal de Mycologie Medicale Apr 2019Dermatophytosis is a frequent cutaneous infection affecting the keratinized tissues of humans, pets and livestock. Animals can carry dermatophytic elements...
BACKGROUND
Dermatophytosis is a frequent cutaneous infection affecting the keratinized tissues of humans, pets and livestock. Animals can carry dermatophytic elements asymptomatically and are considered to play an important role in the epidemiology of the disease. As exposure to any infected lesion free animals, especially cats, may lead to the development of infection in humans.
OBJECTIVES
This study was done to determine the frequency of fungal agents isolated from skin and hair of cats living in rural areas of Meshkin-shahr, Iran.
ANIMALS
A total of 103 asymptomatic cats living in rural areas of the region were studied.
METHODS
This cross-sectional descriptive study was performed in Medical Mycology Laboratory, School of Public Health, Tehran University of Medical Sciences from February 2015 to July 2016. A total of 103 asymptomatic cats were studied. Mycological analysis including direct examination and culture on SC, SCC and DTM of the collected samples were conducted. For molecular confirmation when needed, panfungal PCR targeting the ITS1 region of the rDNA gene cluster using primers ITS1 and ITS4 were performed. Gender and age were also recorded.
RESULTS
None of the 103 cats examined were positive for fungal elements on direct examination. However, 15 (14.5%) cases showed dermatophytes growth. T. verrucosum was the most common etiologic agents of dermatophytosis. Although the gender of the cats had not significant association with dermatophytosis prevalence, age was a significant influential risk factor (P=0.019). Aspergillus spp., Alternaria spp., Rhizopus spp., Penicillium spp.and paecilomyces spp. in descending frequency were the most predominantly identified saprophytic fungi.
CONCLUSION
Our findings clearly highlighted the epidemiological role of asymptomatic cats in spreading dermatophytosis to humans and other animals.
Topics: Animals; Arthrodermataceae; Asymptomatic Infections; Cat Diseases; Cats; Cross-Sectional Studies; DNA, Intergenic; Dermatomycoses; Disease Vectors; Female; Hair; Iran; Male; Polymerase Chain Reaction; Rural Population; Skin
PubMed: 30765158
DOI: 10.1016/j.mycmed.2019.01.004