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Parasitology International Apr 2021Asymptomatic leishmaniasis is believed to play important role in maintaining the transmission of Leishmania spp. within endemic communities. Therefore, the efforts to... (Meta-Analysis)
Meta-Analysis
Asymptomatic leishmaniasis is believed to play important role in maintaining the transmission of Leishmania spp. within endemic communities. Therefore, the efforts to eliminate leishmaniasis are daunting if we cannot manage asymptomatic leishmaniasis well. To clarify the global prevalence and factors associated with the asymptomatic Leishmania infection, we assessed the prevalence of asymptomatic leishmaniasis by a systematic review followed by meta-analyses. In addition, factors associated with the asymptomatic leishmaniasis versus symptomatic were also analyzed. We included all of the original articles alluding to the human asymptomatic leishmaniasis that was confirmed by at least one laboratory diagnosis method regardless of age, sex, race, and ethnicity of the patients, study design, publication date or languages. In total, 111 original articles were chosen for the data extraction. Based on our meta-analyses of the original articles reporting asymptomatic leishmaniasis mostly in endemic areas, the prevalence of asymptomatic leishmaniasis was 11.2% [95% confidence interval (CI) 8.6%-14.4%] in general population, 36.7% [95% CI 27.6%-46.8%] in inhabitants living in the same or neighboring household to the symptomatic patients, and 11.8% [95% CI 7.1%-19%] in HIV infected patients. Among individuals with leishmaniasis, 64.9% [95% CI 54.7%-73.9%] were asymptomatic and males were more susceptible to develop symptoms, with OR=1.88, 95% CI 1.19-2.99, P=0.007. Meta-regression analysis showed no significant change in the prevalence of asymptomatic leishmaniasis during the last 40 years.
Topics: Asymptomatic Infections; Humans; Leishmaniasis; Prevalence; Risk Factors
PubMed: 33144197
DOI: 10.1016/j.parint.2020.102229 -
The Journal of Pediatrics Jul 2020
Topics: Asymptomatic Infections; Bacteriuria; Child; Female; Humans; Pregnancy; Pregnancy Complications, Infectious; Prevalence
PubMed: 32586532
DOI: 10.1016/j.jpeds.2020.04.022 -
Journal of Clinical Virology : the... Jun 2022We clinically characterized PCR detected breakthrough infections among partially/fully vaccinated cases with majority given an inactivated vaccine, CoronaVac. From 1...
We clinically characterized PCR detected breakthrough infections among partially/fully vaccinated cases with majority given an inactivated vaccine, CoronaVac. From 1 March to 15 July 2021, we detected 182 SARS-CoV-2 infections among vaccinated cases with 129 classified as breakthrough infections. Majority were male, 30-39 y.o., and were asymptomatic or mildly symptomatic with few severe cases. Alpha, Beta and Delta VOCs were detected from sequenced breakthrough infections. Healthcare workers had significantly lower Ct values(higher viral loads) versus non-HCWs. Our results underscore the importance of regular PCR screening for HCWs due to the risk of SARS-CoV-2 transmission from asymptomatic breakthrough infections and provide evidence supporting administration of a booster dose especially to HCWs.
Topics: Asymptomatic Infections; COVID-19; COVID-19 Vaccines; Female; Humans; Male; Philippines; SARS-CoV-2
PubMed: 35413587
DOI: 10.1016/j.jcv.2022.105157 -
International Journal of Biological... 2021With ongoing research, it was found that asymptomatic severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection was widespread in coronavirus disease 2019... (Review)
Review
With ongoing research, it was found that asymptomatic severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection was widespread in coronavirus disease 2019 (COVID-19) populations. Studies have confirmed asymptomatic patients with COVID-19 have potential infectivity, and most of the transmission occurred before symptoms appear. Asymptomatic infection rates varied widely in different countries and regions. Identifying the asymptomatic infected persons and cutting off the infection source is an effective way to prevent the spread of this disease. However, asymptomatic patients have hidden clinical symptoms, and screening based only on the clinical symptoms of COVID-19 can easily lead to a missed diagnosis. Therefore, determining asymptomatic infection patients by SARS-CoV-2 nucleic acid testing is the gold standard. A series of prevention and control measures adopted by the Chinese government, especially the "Four Early" policy, have achieved outstanding achievements, which are worth learning from by other countries.
Topics: Asymptomatic Infections; COVID-19; China; Humans; SARS-CoV-2
PubMed: 33867834
DOI: 10.7150/ijbs.59374 -
Journal of Medical Virology Sep 2020On 31 March 2020, Chinese Health Authorization announced that numbers of asymptomatic cases with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection...
On 31 March 2020, Chinese Health Authorization announced that numbers of asymptomatic cases with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection will be made to the public daily. This was a very important step since different counties have different capacities for the detection of SARS-CoV-2 infection and control strategy for the Coronavirus Disease 2019 outbreak. We summarized the characteristics of asymptomatic SARS-CoV-2 infections and the transmission potential of asymptomatic cases. Then we provided guidelines for the management of asymptomatic cases through quarantine and nucleic acid/serology tests.
Topics: Asymptomatic Infections; COVID-19; China; Humans; Pandemics
PubMed: 32383171
DOI: 10.1002/jmv.25990 -
International Journal of Biological... 2020The existence of a substantial but unclear number of asymptomatic SARS-COV-2 patients worldwide has raised concerns among global public health authorities. In this... (Review)
Review
The existence of a substantial but unclear number of asymptomatic SARS-COV-2 patients worldwide has raised concerns among global public health authorities. In this review, according to the published literature, we provided the evidence that asymptomatic infections can result in person-to-person transmission. Four studies suggested that the virus can be transmitted by asymptomatic patients for at least two consecutive generations, indicating its strong infectivity. Asymptomatic infection tends to be, but is not only, identified among young people (<20 years old). The majority of asymptomatic patients appear to have a milder clinical course during hospitalization, but the severity of the symptoms of the secondary patients infected by SARS-COV-2 from asymptomatic patients varies with their physical constitution. The proportion of asymptomatic individuals among all confirmed cases widely differed (from 1.95% to 87.9%) according to the study setting and the populations studied. The increasing large-scale tests are expected to give more information about the true number of asymptomatic infections in the population. In China and other countries, various guidelines for management of asymptomatic cases have been issued. Importantly, early detection, early reporting, early isolation and early treatment of asymptomatic patients require the joint efforts of policy makers, clinicians, technicians, epidemiologists, virologists and patients.
Topics: Adolescent; Asymptomatic Infections; Betacoronavirus; COVID-19; COVID-19 Testing; Clinical Laboratory Techniques; Coronavirus Infections; Critical Illness; Hospitalization; Humans; Infection Control; Pandemics; Pneumonia, Viral; SARS-CoV-2; Young Adult
PubMed: 33061797
DOI: 10.7150/ijbs.48991 -
The Journal of Pediatrics Feb 2020To determine the point prevalence of bacteriuria and bacteriuria without pyuria in asymptomatic children by a systematic review of the literature. (Review)
Review
OBJECTIVE
To determine the point prevalence of bacteriuria and bacteriuria without pyuria in asymptomatic children by a systematic review of the literature.
STUDY DESIGN
We searched MEDLINE and EMBASE for English-, French-, German-, Italian-, and Spanish-language articles. We included articles reporting data on bacteriuria in asymptomatic children up to 19 years of age who had urine collected by suprapubic bladder aspiration, bladder catheterization, or by 3 consecutive clean catch samples. Two independent reviewers assessed studies for inclusion and abstracted data.
RESULTS
Fourteen studies (49 806 children) were included. The prevalence of asymptomatic bacteriuria was 0.37% (95% CI, 0.09-0.82) in boys and 0.47% (95% CI, 0.36-0.59) in girls. The corresponding values for asymptomatic bacteriuria without pyuria were 0.18% (95% CI, 0.02-0.51) and 0.38% (95% CI, 0.22-0.58), respectively. The subgroups with the highest prevalence of asymptomatic bacteriuria were uncircumcised males <1 year of age and females >2 years of age. In males, the prevalence of asymptomatic bacteriuria after infancy was 0.08% (95% CI, 0.01-0.37). The median duration of asymptomatic bacteriuria in untreated boys and girls, from the one study reporting this outcome, was 1.5 and 2 months, respectively.
CONCLUSIONS
Some clinicians are concerned that when a preverbal child with asymptomatic bacteriuria develops a nonlocalizing febrile illness and presents for evaluation, they may be mistakenly diagnosed as having a urinary tract infection (UTI). Given that the prevalence of asymptomatic bacteriuria is considerably lower than the prevalence of UTI in most subgroups examined, this will occur extremely rarely. These data suggest that the current definition of UTI should be revisited.
Topics: Asymptomatic Infections; Bacteriuria; Child; Global Health; Humans; Prevalence
PubMed: 31787323
DOI: 10.1016/j.jpeds.2019.10.019 -
BMC Infectious Diseases Sep 2021Malaria and schistosomiasis present considerable disease burden in tropical and sub-tropical areas and severity is worsened by co-infections in areas where both diseases... (Observational Study)
Observational Study
BACKGROUND
Malaria and schistosomiasis present considerable disease burden in tropical and sub-tropical areas and severity is worsened by co-infections in areas where both diseases are endemic. Although pathogenesis of these infections separately is well studied, there is limited information on the pathogenic disease mechanisms and clinical disease outcomes in co-infections. In this study, we investigated the prevalence of malaria and schistosomiasis co-infections, and the hematologic and blood chemistry abnormalities in asymptomatic adults in a rural fishing community in western Kenya.
METHODS
This sub-study used samples and data collected at enrollment from a prospective observational cohort study (RV393) conducted in Kisumu County, Kenya. The presence of malaria parasites was determined using microscopy and real-time-PCR, and schistosomiasis infection by urine antigen analysis (CCA). Hematological analysis and blood chemistries were performed using standard methods. Statistical analyses were performed to compare demographic and infection data distribution, and hematologic and blood chemistry parameters based on different groups of infection categories. Clinically relevant hematologic conditions were analyzed using general linear and multivariable Poisson regression models.
RESULTS
From February 2017 to May 2018, we enrolled 671 participants. The prevalence of asymptomatic Plasmodium falciparum was 28.2% (157/556) and schistosomiasis 41.2% (229/562), with 18.0% (100/556) of participants co-infected. When we analyzed hematological parameters using Wilcoxon rank sum test to evaluate median (IQR) distribution based on malarial parasites and/or schistosomiasis infection status, there were significant differences in platelet counts (p = 0.0002), percent neutrophils, monocytes, eosinophils, and basophils (p < 0.0001 each). Amongst clinically relevant hematological abnormalities, eosinophilia was the most prevalent at 20.6% (116/562), whereas thrombocytopenia was the least prevalent at 4.3% (24/562). In univariate model, Chi-Square test performed for independence between participant distribution in different malaria parasitemia/schistosomiasis infection categories within each clinical hematological condition revealed significant differences for thrombocytopenia and eosinophilia (p = 0.006 and p < 0.0001, respectively), which was confirmed in multivariable models. Analysis of the pairwise mean differences of liver enzyme (ALT) and kidney function (Creatinine Clearance) indicated the presence of significant differences in ALT across the infection groups (parasite + /CCA + vs all other groups p < .003), but no differences in mean Creatinine Clearance across the infection groups.
CONCLUSIONS
Our study demonstrates the high burden of asymptomatic malaria parasitemia and schistosomiasis infection in this rural population in Western Kenya. Asymptomatic infection with malaria or schistosomiasis was associated with laboratory abnormalities including neutropenia, leukopenia and thrombocytopenia. These abnormalities could be erroneously attributed to other diseases processes during evaluation of diseases processes. Therefore, evaluating for co-infections is key when assessing individuals with laboratory abnormalities. Additionally, asymptomatic infection needs to be considered in control and elimination programs given high prevalence documented here.
Topics: Adult; Asymptomatic Infections; Coinfection; Cross-Sectional Studies; Humans; Kenya; Malaria; Malaria, Falciparum; Plasmodium falciparum; Prevalence; Prospective Studies; Rural Population; Schistosomiasis
PubMed: 34503469
DOI: 10.1186/s12879-021-06626-2 -
Frontiers in Public Health 2022The dynamic transmission of asymptomatic and symptomatic COVID-19 infections is difficult to quantify because asymptomatic infections are not readily recognized or...
The dynamic transmission of asymptomatic and symptomatic COVID-19 infections is difficult to quantify because asymptomatic infections are not readily recognized or self-identified. To address this issue, we collected data on asymptomatic and symptomatic infections from four Chinese regions (Beijing, Dalian, Xinjiang, and Guangzhou). These data were considered reliable because the government had implemented large-scale multiple testing during the outbreak in the four regions. We modified the classical susceptible-exposure-infection-recovery model and combined it with mathematical tools to quantitatively analyze the number of infections caused by asymptomatic and symptomatic infections during dynamic transmission, respectively. The results indicated that the ratios of the total number of asymptomatic to symptomatic infections were 0.13:1, 0.48:1, 0.29:1, and 0.15:1, respectively, in the four regions. However, the ratio of the total number of infections caused by asymptomatic and symptomatic infections were 4.64:1, 6.21:1, 1.49:1, and 1.76:1, respectively. Furthermore, the present study describes the daily number of healthy people infected by symptomatic and asymptomatic transmission and the dynamic transmission process. Although there were fewer asymptomatic infections in the four aforementioned regions, their infectivity was found to be significantly higher, implying a greater need for timely screening and control of infections, particularly asymptomatic ones, to contain the spread of COVID-19.
Topics: Asymptomatic Infections; COVID-19; China; Disease Outbreaks; Humans; SARS-CoV-2
PubMed: 36249263
DOI: 10.3389/fpubh.2022.925492 -
American Journal of Infection Control Sep 2020Humans are generally susceptible to SARS-CoV-2, which has caused a global pandemic of COVID-19. The screening of infected people in the population still mainly depends...
BACKGROUND
Humans are generally susceptible to SARS-CoV-2, which has caused a global pandemic of COVID-19. The screening of infected people in the population still mainly depends on clinical symptoms. However, there is limited research on the characteristics of clinical symptoms in different populations, especially in imported cases.
METHODS
To retrospectively analyze the clinical data of 494 confirmed COVID-19 patients admitted to a designated hospital in Shanghai from January 20, 2020, to March 31, 2020, we compared the clinical manifestations in different populations and their influencing factors in COVID-19 patients.
RESULTS
(1) Of the 494 patients, 453 (91.7%) had different symptoms at admission, and 39 (7.89%) patients were asymptomatic. (2) We compared the symptoms of patients according to different stratifications and found the following results: (a) The proportion of dyspnea was significantly higher in male patients than in female patients (P < .05). (b) The proportions of a stuffy nose, sore throat, and olfactory and gustatory dysfunction were significantly higher in children than in adult patients (P < .05). (c) The proportions of fever, chest tightness, shortness of breath, and fatigue were significantly higher in local cases than in imported cases. In comparison, the proportions of nasal congestion, stuffy nose, sore throat, headache, and olfactory and gustatory dysfunction were significantly lower in imported cases than in imported cases (P < .05). (d) The proportions of chest tightness, shortness of breath, and dyspnea were significantly higher in severely ill patients than in those with mild symptoms (P < .05). (3) Thirty-one asymptomatic patients were significantly younger than symptomatic patients, and they had a higher proportion of imported cases, white blood cell and lymphocyte count levels, and fewer abnormal CT cases than the group of symptomatic patients (P < .05). (4) The number of days since the onset of the disease needed for the symptoms to disappear was associated with the epidemiological history (imported cases), the number of days until the pharyngeal swab nucleic acid test turned negative, the days of hospitalization, the days of onset, and the white blood cell and lymphocyte count levels (P < .05).
CONCLUSIONS
The majority of COVID-19 patients (91.7%) had early symptoms, whereas 7.89% of COVID-19 patients were asymptomatic. Younger patients had fewer symptoms, mainly the upper respiratory symptoms, and the illness condition was milder, which was more common in imported cases. Elderly male patients had severe symptoms when admitted. The number of days needed for the patient's symptoms to disappear was closely related to the number of days necessary for the pharyngeal swab nucleic acid test to turn negative.
Topics: Adolescent; Adult; Age Factors; Aged; Asymptomatic Infections; Betacoronavirus; COVID-19; China; Coronavirus Infections; Female; Humans; Male; Middle Aged; Pandemics; Pneumonia, Viral; Retrospective Studies; SARS-CoV-2; Severity of Illness Index; Young Adult
PubMed: 32645475
DOI: 10.1016/j.ajic.2020.06.221