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Enfermedades Infecciosas Y... Jul 2016Parasitic diseases suppose an important health problem in people from high endemic areas, so these must be discarded properly. Usually, these infections develop...
Parasitic diseases suppose an important health problem in people from high endemic areas, so these must be discarded properly. Usually, these infections develop asymptomatically but, in propitious situations, are likely to reactivate themselves and can cause clinical symptoms and/or complications in the receiving country. Moreover, in some cases it is possible local transmission. Early diagnosis of these parasitic diseases made by appropriate parasitological techniques and its specific treatment will benefit both, the individual and the community. These techniques must be selected according to geoepidemiological criteria, patient's origin, migration route or time spent outside the endemic area; but other factors must also be considered as its sensitivity and specificity, implementation experience and availability. Given the high prevalence of intestinal parasites on asymptomatic immigrants, it is recommended to conduct a study by coproparasitological techniques. Because of its potential severity, the screening of asymptomatic malaria with sensitive techniques such as PCR (polymerase chain reaction) is also advisable. Serological screening for Chagas disease should be performed on all Latin American immigrants, except for people from the Caribbean islands. Other important parasites, which should be excluded, are filariasis and urinary schistosomiasis, by using microscopic examination. The aim of this paper is to review the different techniques for the screening of parasitic diseases and its advices within the care protocols for asymptomatic immigrants.
Topics: Asymptomatic Infections; Chagas Disease; Emigrants and Immigrants; Humans; Intestinal Diseases, Parasitic; Malaria; Parasitic Diseases; Prevalence; Sensitivity and Specificity
PubMed: 27474244
DOI: 10.1016/S0213-005X(16)30216-6 -
Frontiers in Neurology 2017Deficits in visual acuity, visual field, and oculomotor function are commonly detected after repair of cerebral aneurysms. However, when these deficits are absent, it...
Deficits in visual acuity, visual field, and oculomotor function are commonly detected after repair of cerebral aneurysms. However, when these deficits are absent, it does not mean that other potential visual deficits also are absent. Here, we report three cases that after complete recover from surgical repair of cerebral aneurysms presented minimal visual acuities of about 20/20 and no visual disturbances. While two of them (Cases 1 and 2) showed visual fields with no relevant central defects, two of them showed relevant impairments in spatial contrast sensitivity (Cases 2 and 3). This evidence supports that after complete recover from surgical repair of hemorrhagic cerebral aneurysms spatial contrast sensitivity can be asymptomatically impaired when visual acuity (Cases 2 and 3) and visual fields (Case 2) are not correlated with symptoms of visual disturbances. Hypothetical explanations and consequences of such evidence are discussed.
PubMed: 28983277
DOI: 10.3389/fneur.2017.00487 -
QJM : Monthly Journal of the... Aug 2020Duration of persistence of SARS-CoV-2 in the upper respiratory tract of infected individuals has important clinical and epidemiological implications.
BACKGROUND
Duration of persistence of SARS-CoV-2 in the upper respiratory tract of infected individuals has important clinical and epidemiological implications.
AIM
We aimed to establish the duration and risk factors for persistence of SARS-CoV-2 in the upper respiratory tract of asymptomatic infected individuals.
METHODS
Data of repeat rRT-PCR (real-time reverse transcription-polymerase chain reaction) test done for SARS-CoV-2 infected individuals at our institute at Jodhpur, India were analysed from 19 March to 21 May 2020. Duration of virus persistence was estimated with parametric regression models based on weibull, log-normal, log-logistic, gamma and generalized gamma distributions. Factors associated with prolonged viral persistence were analysed with the best-fitting model.
RESULTS
Fifty-one SARS-CoV-2 infected individuals with repeat rRT-PCR test were identified with 44 asymptomatics. The asymptomatic individuals had median virus persistence duration of 8.87 days (95% CI: 7.65-10.27) and 95 percentile duration of 20.70 days (95% CI: 16.08-28.20). The overall median virus persistence including both symptomatic and asymptomatic individuals was found to be 9.18 days (95% CI: 8.04-10.48). Around one-fourth asymptomatics (10/44) demonstrated SARS-CoV-2 persistence beyond 2 weeks. Age <60 years and local transmission were found to be significantly associated with longer virus persistence among asymptomatic individuals on univariate regression but not in multivariate analysis.
CONCLUSION
Recommended home isolation duration for SARS-CoV-2 infected individuals in India should be extended from 17 days to at least 3 weeks. Prolonged persistence of SARS-CoV-2 in a considerable proportion of asymptomatic individuals merits attention with regard to ensuring universal infection prevention precautions irrespective of symptomatic status.
Topics: Adolescent; Adult; Age Factors; Aged; Asymptomatic Infections; Betacoronavirus; COVID-19; COVID-19 Testing; Clinical Laboratory Techniques; Coronavirus Infections; Female; Humans; India; Male; Middle Aged; Nasopharynx; Oropharynx; Pandemics; Pneumonia, Viral; Reverse Transcriptase Polymerase Chain Reaction; Risk Factors; SARS-CoV-2; Time Factors; Virus Shedding; Young Adult
PubMed: 32609360
DOI: 10.1093/qjmed/hcaa212 -
Cellular Microbiology Dec 2010Entamoeba histolytica causes an estimated 100,000 deaths per year and is one of the leading causes of death among parasitic infections. Studies using E.... (Review)
Review
Entamoeba histolytica causes an estimated 100,000 deaths per year and is one of the leading causes of death among parasitic infections. Studies using E. histolytica-specific polymerase chain reaction identified that 13.8% of adults in a rural Mexican community and 11.2% of adults in central Vietnam are asymptomatically colonized. Such high incidents of asymptomatic infection suggest that only a minority of infections proceed to invasive disease. Understanding the mechanisms that underpin variable disease outcome will be critical in developing therapeutic strategies. In recent years there have been a plethora of gene expression profiling data documenting the transcriptome differences between virulent and non-virulent strains of E. histolytica as well as changes induced by external environmental changes or stimuli. While these studies have successfully identified co-regulated genes and potential virulence factors, there is still little known about the transcriptional mechanisms that induce the changes observed in this non-model organism. In this review, we have looked at how molecular technological advances have shaped our understanding of transcriptional regulation in amoeba and what we may expect from the application of powerful new techniques.
Topics: Entamoeba histolytica; Gene Expression Profiling; Gene Expression Regulation; Parasitology
PubMed: 20812994
DOI: 10.1111/j.1462-5822.2010.01524.x -
The Pediatric Infectious Disease Journal Dec 1995Little information is available on asymptomatic carriage of Cryptosporidium in immunocompetent and immunodeficient children. We prospectively studied a group of...
Little information is available on asymptomatic carriage of Cryptosporidium in immunocompetent and immunodeficient children. We prospectively studied a group of asymptomatic children, 78 immunocompetent and 50 immunodeficient, to document the incidence of asymptomatic carriage of cryptosporidiosis in such a population. We also investigated whether the treatment of children who carried asymptomatic cryptosporidiosis could help in reducing their risk of gastrointestinal symptoms as well as the shedding of infectious oocysts. The occurrence of multiple infections with common intestinal pathogens including Giardia lamblia was also investigated. Asymptomatic cryptosporidiosis was documented in 6.4% of immunocompetent and 22% of immunodeficient children. In a control symptomatic population Cryptosporidium was found in 4.4% of immunocompetent and 4.8% of immunodeficient children. Asymptomatic carriage of Cryptosporidium was documented in 2 human immunodeficiency virus-infected children, one of whom also carried Giardia asymptomatically. Treatment with spiramycin (100 mg/kg daily for 14 days) reduced significantly the duration of the shedding of potentially infectious oocysts. Finally no gastrointestinal symptoms developed in children treated for asymptomatic infection with Cryptosporidium, whereas children who were not treated developed gastrointestinal symptoms.
Topics: Adolescent; Animals; Anti-Bacterial Agents; Carrier State; Child; Child, Preschool; Cryptosporidiosis; Cryptosporidium; Feces; Giardia lamblia; Humans; Immunocompetence; Immunologic Deficiency Syndromes; Infant; Prospective Studies; Spiramycin
PubMed: 8745015
DOI: 10.1097/00006454-199512000-00003 -
China CDC Weekly Mar 2021
SUMMARY
UNLABELLED
Patients with coronavirus disease 2019 (COVID-19) infection can be categorized by severity: asymptomatic infection, mild illness, moderate illness, severe illness, and critical illness. The rate of transmission to a specific group of contacts (the secondary attack rate) may be 3-25 times lower from people who are asymptomatically infected than from those with symptoms. The incubation period is 2-14 days.
UNLABELLED
UNLABELLED
An individual with asymptomatic infection shed live virus that started a 42-case outbreak in Shunyi District of Beijing in December 2020. The individual had been quarantined for 14 days in a designated quarantine hotel in Fuzhou after entering China from Indonesia. During quarantine, he had 5 negative throat swab tests and 2 negative IgM serum tests. The investigation team determined that the incubation periods of 31 confirmed cases ranged from 2 to 23 days.
UNLABELLED
UNLABELLED
The frequency of nucleic acid testing should be increased for international entrants and people who are close contacts of confirmed COVID-19 cases. The investigation team recommend expanding sample types for nucleic acid testing to include anal swabs and residential environmental sampling; serum antibody testing can be used as a reference indicator. Parallel testing by two institutions at key points in time, such as the end of isolation, should be implemented.
PubMed: 34594852
DOI: 10.46234/ccdcw2020.062 -
Journal of Fungi (Basel, Switzerland) Dec 2021is the major pathogen of the pea root rot complex in Europe. This wide host range pathogen often asymptomatically colonizes its hosts, making the control strategies...
is the major pathogen of the pea root rot complex in Europe. This wide host range pathogen often asymptomatically colonizes its hosts, making the control strategies challenging. We developed a real-time PCR assay for the detection and quantification of based on the gene sequence alignments. The assay was tested for specificity on a 54-isolate panel representing 35 fungal species and further validated in symptomatic and asymptomatic pea and wheat roots from greenhouse tests. The assay was highly consistent across separate qPCR reactions and had a quantification/detection limit of 3.1 pg of target DNA per reaction in plant tissue. Cross-reactions were observed with DNA extracts of five species. The risk of cross contamination, however, is low as the non-targets have not been associated with pea previously and they were amplified with at least 1000-fold lower sensitivity. Greenhouse inoculation tests revealed a high correlation between the pathogen DNA quantities in pea roots and pea root rot severity and biomass reduction. The assay also detected in asymptomatic wheat roots, which, despite the absence of visible root rot symptoms, caused wheat biomass reduction. This study provides new insights into the complex life style of and can assist in better understanding the pathogen survival and spread in the environment.
PubMed: 35049982
DOI: 10.3390/jof8010041 -
PloS One 2014There is increasing interest in the role of asymptomatic infection in transmission of Visceral Leishmaniasis (VL). We studied the individual, household and environmental... (Randomized Controlled Trial)
Randomized Controlled Trial
There is increasing interest in the role of asymptomatic infection in transmission of Visceral Leishmaniasis (VL). We studied the individual, household and environmental factors associated with asymptomatic Leishmania donovani infected individuals and VL. 7,538 individuals living in VL endemic villages in India and Nepal were divided into three mutually exclusive groups based on their VL history and Direct Agglutination Test (DAT) results in yearly serosurveys over a two-year period. The groups were (1) VL cases, (2) asymptomatically infected individuals (seroconverters) and (3) seronegative individuals. VL cases and seroconverters were compared to seronegative individuals in mixed logistic regression models. The risk of seroconversion and disease was significantly increased in individuals aged 14 to 24 years old and by the presence of other DAT-positive, asymptomatically infected individuals and VL cases in the house. The risk of seroconversion was higher in Indian than in Nepalese villages and it increased significantly with age, but not so for VL. This study demonstrates that, when risk factors for leishmanial infection and VL disease are evaluated in the same population, epidemiological determinants for asymptomatic infection and VL are largely similar.
Topics: Adolescent; Adult; Child; Child, Preschool; Female; Follow-Up Studies; Humans; India; Infant; Infant, Newborn; Leishmania donovani; Leishmaniasis, Visceral; Male; Models, Biological; Nepal; Risk Factors
PubMed: 24498159
DOI: 10.1371/journal.pone.0087641 -
APMIS : Acta Pathologica,... May 2013Oropharyngeal candidiasis (OPC) is a very common oral symptom for HIV infected patients. OPC is often caused by overgrowth of commensal Candida strains which... (Review)
Review
Oropharyngeal candidiasis (OPC) is a very common oral symptom for HIV infected patients. OPC is often caused by overgrowth of commensal Candida strains which asymptomatically colonize oral cavity of HIV+ patients. HIV infection can not only weaken the systemic and local mucosal immunity but also interact with Candida species colonizing in oral cavity. These changes in host immunity and Candida species may facilitate Candida colonization in oral cavity of HIV infected patients. This review will discuss oral Candida colonization (including asymptomatic Candida carriage and OPC) prevalence, colonization spectrum, colonization intensity, relationship between oropharyngeal Candida colonization and peripheral blood CD4+ T cell counts, association of plasma levels of HIV RNA and Candida colonization, and other factors related with Candida colonization in HIV+ patients.
Topics: AIDS-Related Opportunistic Infections; CD4-Positive T-Lymphocytes; Candida; Candidiasis, Oral; HIV; HIV Infections; Humans; Immunity, Mucosal; Mouth Mucosa; Oropharynx; RNA, Viral
PubMed: 23030258
DOI: 10.1111/apm.12006 -
PloS One 2019Clostridium difficile (CD) is the leading cause of infectious health-care associated diarrhea. However, little is known regarding CD carriage and transmission amongst...
BACKGROUND
Clostridium difficile (CD) is the leading cause of infectious health-care associated diarrhea. However, little is known regarding CD carriage and transmission amongst asymptomatic colonizers. We evaluated carriage, characterized strains and examined epidemiologic linkages in asymptomatic colonized CD patients.
METHODS
Rectal swabs from asymptomatic patients admitted to the general medicine ward from April 1-June 30 2012 were collected. PCR-confirmed CD colonies were ribotyped and characterized by Modified-Multi Locus Variable Number Tandem Repeat Analysis (MMLVA).
RESULTS
1549-swabs were collected from 474-patients. Overall, 50/474(10.6%) were CD PCR-positive, 24/50 were colonized at admission, while 26/50 were first identified > = 72 hours after admission. Amongst the 50 CD PCR-positive patients, 90% were asymptomatically colonized and 80% of individuals carried toxigenic CD-strains, including ribotype-027 (5/45:11%). MMLVA revealed five-clusters involving 15-patients harboring toxigenic (4/5) and non-toxigenic CD strains (1/5). In two clusters, patients were CD positive on admission while in the other three clusters involving 10 patients, we observed CD transmission from asymptomatically colonized patients to 8 previously CD-negative patients.
CONCLUSIONS
We identified increasing rates of colonization during admission to medical wards. MMLVA typing effectively discriminated between strains and suggests that 20% of patients with CD colonization acquired their strain(s) from asymptomatically colonized individuals in hospital.
Topics: Adolescent; Adult; Aged; Aged, 80 and over; Carrier State; Clostridioides difficile; Clostridium Infections; Cross Infection; Diarrhea; Feces; Female; Hospitalization; Humans; Male; Middle Aged; Prospective Studies; Rectum; Ribotyping; Tertiary Care Centers; Young Adult
PubMed: 30742636
DOI: 10.1371/journal.pone.0207138