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The American Journal of Tropical... Nov 2021Asymptomatic malarial parasitemia is highly prevalent in Plasmodium falciparum endemic areas and often associated with increased prevalence of mild to moderate anemia....
High Prevalence of Asymptomatic Malarial Anemia and Association with Early Conversion from Asymptomatic to Symptomatic Infection in a Plasmodium falciparum Hyperendemic Setting in Cameroon.
Asymptomatic malarial parasitemia is highly prevalent in Plasmodium falciparum endemic areas and often associated with increased prevalence of mild to moderate anemia. The aim of this study was to assess the prevalence of anemia during asymptomatic malaria parasitemia and its interplay with persistent infection in highly exposed individuals. A household-based longitudinal survey was undertaken in a malaria hyperendemic area in Cameroon using multiplex nested polymerase chain reaction to detect plasmodial infections. Residents with P. falciparum asymptomatic parasitemia were monitored over a 3-week period with the aid of structured questionnaires and weekly measurements of axillary temperatures. Of the 353 individuals included (median age: 26 years, range 2-86 years, male/female sex ratio 0.9), 328 (92.9%) were positive for malaria parasitemia of whom 266 (81.1%) were asymptomatic carriers. The prevalence of anemia in the study population was 38.6%, of which 69.2% were asymptomatic. Multivariate analyses identified high parasitemia (> 327 parasites/µL) and female gender as associated risk factors of asymptomatic malarial anemia in the population. Furthermore, risk analyses revealed female gender and anemia at the time of enrolment as key predictors of early development of febrile illness (< 3 weeks post enrolment) among the asymptomatic individuals. Together, the data reveal an extremely high prevalence of asymptomatic malaria parasitemia and anemia in the study area, unveiling for the first time the association of asymptomatic malarial anemia with early clinical conversion from asymptomatic to symptomatic infection. Furthermore, these findings underscore the negative impact of asymptomatic malaria parasitemia on individual health, necessitating the development of appropriate control and preventive measures.
Topics: Adolescent; Anemia; Asymptomatic Diseases; Cameroon; Child; Child, Preschool; Endemic Diseases; Female; Humans; Malaria, Falciparum; Male; Prevalence
PubMed: 34724628
DOI: 10.4269/ajtmh.21-0316 -
Travel Medicine and Infectious Disease 2020Asymptomatic infection of SARS-CoV-2 has become a concern worldwide. This study aims to compare the epidemiology and the clinical characteristics of SARS-CoV-2 infection...
OBJECTIVES
Asymptomatic infection of SARS-CoV-2 has become a concern worldwide. This study aims to compare the epidemiology and the clinical characteristics of SARS-CoV-2 infection in asymptomatic and symptomatic individuals.
METHODS
A total of 511 confirmed SARS-CoV-2 infection cases, including 100 asymptomatic (by the time of the pathogenic tests) and 411 symptomatic individuals were consecutively enrolled from January 25 to February 20, 2020 from hospitals in 21 cities and 47 counties or districts in Sichuan Province. Epidemiological and clinical characteristics were compared.
RESULTS
Compared to the symptomatic patients, the asymptomatic cases were younger (P < 0.001), had similar co-morbidity percentages (P = 0.609), and came from higher altitude areas with lower population mobility (P < 0.001) with better defined epidemiological history (P < 0.001). 27.4% of well-documented asymptomatic cases developed delayed symptoms after the pathogenic diagnosis. 60% of asymptomatic cases demonstrated findings of pneumonia on the initial chest CT, including well-recognized features of coronavirus disease-19. None of the asymptomatic individuals died. Two elderly individuals with initially asymptomatic infection developed severe symptoms during hospitalization. One case of possible virus transmission by a patient during the incubation period was highly suspected.
CONCLUSIONS
The epidemiological and clinical findings highlight the significance of asymptomatic infection with SARS-CoV-2. Inspecting the epidemiological history would facilitate the identification of asymptomatic cases. Evidence supports the chest CT scans for confirmed asymptomatic cases to evaluate the extent of lung involvement.
Topics: Adolescent; Adult; Aged; Aged, 80 and over; Asymptomatic Infections; Betacoronavirus; COVID-19; Child; Child, Preschool; China; Coronavirus Infections; Female; Humans; Infant; Male; Middle Aged; Pandemics; Pneumonia, Viral; Retrospective Studies; Risk Factors; SARS-CoV-2; Time Factors; Young Adult
PubMed: 32492485
DOI: 10.1016/j.tmaid.2020.101754 -
Pharmaceutics Apr 2023Pancreatic cancer is fast becoming a global menace and it is projected to be the second leading cause of cancer-related death by 2030. Pancreatic adenocarcinomas, which... (Review)
Review
Pancreatic cancer is fast becoming a global menace and it is projected to be the second leading cause of cancer-related death by 2030. Pancreatic adenocarcinomas, which develop in the pancreas' exocrine region, are the predominant type of pancreatic cancer, representing about 95% of total pancreatic tumors. The malignancy progresses asymptomatically, making early diagnosis difficult. It is characterized by excessive production of fibrotic stroma known as desmoplasia, which aids tumor growth and metastatic spread by remodeling the extracellular matrix and releasing tumor growth factors. For decades, immense efforts have been harnessed toward developing more effective drug delivery systems for pancreatic cancer treatment leveraging nanotechnology, immunotherapy, drug conjugates, and combinations of these approaches. However, despite the reported preclinical success of these approaches, no substantial progress has been made clinically and the prognosis for pancreatic cancer is worsening. This review provides insights into challenges associated with the delivery of therapeutics for pancreatic cancer treatment and discusses drug delivery strategies to minimize adverse effects associated with current chemotherapy options and to improve the efficiency of drug treatment.
PubMed: 37242560
DOI: 10.3390/pharmaceutics15051318 -
MBio Oct 2023Herpes simplex virus-1 (HSV-1) is a human pathogen known to cause cold sores and genital herpes. HSV-1 establishes lifelong infections in our sensory neurons, with no...
Herpes simplex virus-1 (HSV-1) is a human pathogen known to cause cold sores and genital herpes. HSV-1 establishes lifelong infections in our sensory neurons, with no cure or vaccine available. HSV-1 can reactivate sporadically and travel back along sensory nerves, where it can form lesions in the oral and genital mucosa, eye, and skin, or be shed asymptomatically. New treatment options are needed as resistance is emerging to current antiviral therapies. Here, we show that interferons (IFNs) are capable of blocking virus release from nerve endings, potentially stopping HSV-1 transmission into the skin. Furthermore, we show that IFNγ has the potential to have widespread antiviral effects in the neuron and may have additional effects on HSV-1 reactivation. Together, this study identifies new targets for the development of immunotherapies to stop the spread of HSV-1 from the nerves into the skin.
Topics: Humans; Herpesvirus 1, Human; Interferons; Sensory Receptor Cells; Axons; Antiviral Agents; Herpes Simplex
PubMed: 37655893
DOI: 10.1128/mbio.01818-23 -
Acta Neurochirurgica Sep 2020Many meningiomas are detected incidentally and remain asymptomatic until intervention. The goal of this study was to describe the management and outcome in this group of...
BACKGROUND
Many meningiomas are detected incidentally and remain asymptomatic until intervention. The goal of this study was to describe the management and outcome in this group of surgically treated asymptomatic meningiomas.
METHODS
From 2004 to 2017, 45 patients with asymptomatic meningioma were surgically treated at Sahlgrenska University Hospital, and their medical records and imaging data were analyzed. The asymptomatic cases were matched with symptomatic ones with respect to age at diagnosis, location, WHO (World Health Organization) grade, and Simpson grade.
RESULTS
Time from diagnosis to surgery differed between the asymptomatic and symptomatic patients (8.6 vs. 1.3 months; p < 0.001). Of symptomatic patients, 32.6% still used anti-epileptic drugs > 1 year after surgery, compared with 7.7% of the asymptomatic (p = 0.003). Thirty-day complication rate was significantly higher among the asymptomatic cases (35.6% vs. 24.4%; 0.001), as well as the proportion of older asymptomatic individuals (> 70 years) experiencing postoperative complication compared with symptomatic patients of the same age group.
CONCLUSION
As expected, asymptomatic cases had smaller tumors and waited longer for surgery. Surprisingly, complication rate was significantly higher among asymptomatic cases compared with their symptomatic control. Taken into account that many asymptomatic tumors are removed surgically due to patient's wish, one might suggest a more restrictive approach, especially in the elderly.
Topics: Adult; Aged; Aged, 80 and over; Asymptomatic Diseases; Case-Control Studies; Female; Humans; Male; Meningeal Neoplasms; Meningioma; Middle Aged; Postoperative Complications
PubMed: 32016587
DOI: 10.1007/s00701-020-04244-6 -
FEMS Microbiology Reviews Jan 2022Staphylococcus aureus is an opportunistic human pathogen, which is a leading cause of infections worldwide. The challenge in treating S. aureus infection is linked to... (Review)
Review
Staphylococcus aureus is an opportunistic human pathogen, which is a leading cause of infections worldwide. The challenge in treating S. aureus infection is linked to the development of multidrug-resistant strains and the mechanisms employed by this pathogen to evade the human immune defenses. In addition, S. aureus can hide asymptomatically in particular 'protective' niches of the human body for prolonged periods of time. In the present review, we highlight recently gained insights in the role of the human gut as an endogenous S. aureus reservoir next to the nasopharynx and oral cavity. In addition, we address the contribution of these ecological niches to staphylococcal transmission, including the roles of particular triggers as modulators of the bacterial dissemination. In this context, we present recent advances concerning the interactions between S. aureus and immune cells to understand their possible roles as vehicles of dissemination from the gut to other body sites. Lastly, we discuss the factors that contribute to the switch from colonization to infection. Altogether, we conclude that an important key to uncovering the pathogenesis of S. aureus infection lies hidden in the endogenous staphylococcal reservoirs, the trafficking of this bacterium through the human body and the subsequent immune responses.
Topics: Humans; Staphylococcal Infections; Staphylococcus aureus
PubMed: 34259843
DOI: 10.1093/femsre/fuab041 -
Frontiers in Immunology 2022Multiple sclerosis (MS) is a chronic disease of the central nervous system (CNS), marked primarily by demyelination, inflammation, and neurodegeneration. While the... (Review)
Review
Multiple sclerosis (MS) is a chronic disease of the central nervous system (CNS), marked primarily by demyelination, inflammation, and neurodegeneration. While the prevalence and incidence rates of MS are on the rise, the etiology of the disease remains enigmatic. Nevertheless, it is widely acknowledged that MS develops in persons who are both genetically predisposed and exposed to a certain set of environmental factors. One of the most plausible environmental culprits is Epstein-Barr virus (EBV), a common herpesvirus asymptomatically carried by more than 90% of the adult population. How EBV induces MS pathogenesis remains unknown. A comprehensive understanding of the biology of EBV infection and how it contributes to dysfunction of the immune system and CNS, requires an appreciation of the viral dynamics within the host. Here, we aim to outline the different animal models, including nonhuman primates (NHP), rodents, and rabbits, that have been used to elucidate the link between EBV and MS. This review particularly focuses on how the disruption in virus-immune interaction plays a role in viral pathogenesis and promotes neuroinflammation. We also summarize the effects of virus titers, age of animals, and route of inoculation on the neuroinvasiveness and neuropathogenic potential of the virus. Reviewing the rich data generated from these animal models could provide directions for future studies aimed to understand the mechanism(s) by which EBV induces MS pathology and insights for the development of prophylactic and therapeutic interventions that could ameliorate the disease.
Topics: Animals; Rabbits; Herpesvirus 4, Human; Multiple Sclerosis; Epstein-Barr Virus Infections; Serologic Tests; Models, Animal
PubMed: 36466898
DOI: 10.3389/fimmu.2022.1036155 -
Talanta Mar 2022Asymptomatic infection of COVID-19 is a global threat for public health. Unfortunately, the study about metabolic dysregulation of asymptomatic infection is barely...
Asymptomatic infection of COVID-19 is a global threat for public health. Unfortunately, the study about metabolic dysregulation of asymptomatic infection is barely investigated. Here, we performed carboxylic submetabolome profiling of serum from 62 asymptomatic and 122 control individuals, by a highly sensitive chemical isotope labelling method. Twenty-one discriminative carboxylic features, including 12-hydroxyeicosatetraenoic acid, cholic acid, glycoursodeoxycholic acid and 15,16-dihydroxyoctadeca-9,12-dienoic acid were discovered to be dysregulated in asymptomatic patients. This panel containing 21 carboxylic features could accurately identify asymptomatic patients based on a random forest model, providing an accuracy of 85.7% with only 3.6% false positive rate and 7.1% false negative rate. The dysregulated metabolites found in asymptomatic patients covered several important pathways, such as arachidonic acid metabolism, synthesis of bile acid, β-oxidation of fatty acids, activation of macrophage and platelet aggregation. This work provided valuable knowledge about serum biomarkers and molecular clues associated with asymptomatic COVID-19 patients.
Topics: Asymptomatic Infections; COVID-19; Fatty Acids; Humans; Isotope Labeling; SARS-CoV-2
PubMed: 34871866
DOI: 10.1016/j.talanta.2021.123086 -
Viruses Aug 2022Animal models that mimic human infections provide insights in virus-host interplay; knowledge that in vitro approaches cannot readily predict, nor easily reproduce.... (Review)
Review
Animal models that mimic human infections provide insights in virus-host interplay; knowledge that in vitro approaches cannot readily predict, nor easily reproduce. Human cytomegalovirus (HCMV) infections are acquired asymptomatically, and primary infections are difficult to capture. The gap in our knowledge of the early events of HCMV colonization and spread limits rational design of HCMV antivirals and vaccines. Studies of natural infection with mouse cytomegalovirus (MCMV) have demonstrated the olfactory epithelium as the site of natural colonization. Systemic spread from the olfactory epithelium is facilitated by infected dendritic cells (DC); tracking dissemination uncovered previously unappreciated DC trafficking pathways. The olfactory epithelium also provides a unique niche that supports efficient MCMV superinfection and virus recombination. In this review, we summarize recent advances to our understanding of MCMV infection and spread and the tissue-specific mechanisms utilized by MCMV to modulate DC trafficking. As these mechanisms are likely conserved with HCMV, they may inform new approaches for preventing HCMV infections in humans.
Topics: Animals; Antiviral Agents; Cytomegalovirus; Cytomegalovirus Infections; Disease Models, Animal; Herpesviridae Infections; Humans; Mice; Muromegalovirus
PubMed: 36146741
DOI: 10.3390/v14091934 -
Frontiers in Cellular and Infection... 2022The Gram-positive bacterial pathogen, is a major global health threat that kills over one million people worldwide. The pneumococcus commonly colonizes the nasopharynx... (Review)
Review
The Gram-positive bacterial pathogen, is a major global health threat that kills over one million people worldwide. The pneumococcus commonly colonizes the nasopharynx asymptomatically as a commensal, but is also capable of causing a wide range of life-threatening diseases such as pneumonia, meningitis and septicemia upon migration into the lower respiratory tract and spread to internal organs. Emergence of antibiotic resistant strains and non-vaccine serotypes has led to the classification of pneumococcal bacteria as a priority pathogen by the World Health Organization that needs urgent research into bacterial pathogenesis and development of novel vaccine strategies. Extracellular vesicles are spherical membrane bound structures that are released by both pathogen and host cells, and influence bacterial pathogenesis as well as the immune response. Recent studies have found that while bacterial vesicles shuttle virulence factors and toxins into host cells and regulate inflammatory responses, vesicles released from the infected host cells contain both bacterial and host proteins that are antigenic and immunomodulatory. Bacterial membrane vesicles have great potential to be developed as cell-free vaccine candidates in the future due to their immunogenicity and biostability. Host-derived vesicles isolated from patient biofluids such as blood and bronchoalveolar lavage could be used to identify potential diagnostic biomarkers as well as engineered to deliver desired payloads to specific target cells for immunotherapy. In this review, we summarize the recent developments on the role of bacterial and host vesicles in pneumococcal infections and future prospects in developing novel therapeutics and diagnostics for control of invasive pneumococcal diseases.
Topics: Extracellular Vesicles; Humans; Immunologic Factors; Pneumococcal Infections; Pneumococcal Vaccines; Streptococcus pneumoniae
PubMed: 35237534
DOI: 10.3389/fcimb.2022.836070