Unrecognized Infection Research Articles

Multiparametric Flow Cytometry Analysis of Naïve, Memory, and Effector T Cells.

Polychromatic flow cytometry enables the detection and characterization of markers which are helpful in defining phenotype of various cell subsets. Here we describe flow cytometry-based method to characterize phenotype of naïve, memory, and effector T cells. Being able to differentiate these cells is crucial in understanding immune response, and immune profiling. Naïve T cells enable the body to fight off new, unrecognized infections and diseases, and memory T cells are enriched for response to recall antigens. Furthermore, the antigen-experienced T cell populations can be broadly divided into effector and memory cell compartments, both of which are needed for sustaining a responsive immune system. Simplistically, the effector T cells require active antigenic stimulation to eliminate pathogens. On the other hand, memory T cells are described as cells which remain present in the absence of antigenic stimulation and have the capacity to expand rapidly upon secondary challenges. Recently, with the identification of central and effector memory T cell subsets, tremendous efforts have been devoted to characterize markers on the surfaces of these cells. Though, various markers have been used to identify the subsets, no single marker that segregates one subset from the other has been described. Thus, multiple markers are needed to subset the cells in order to characterize them. Here we report the verification of a nine-color panel (CD3, CD4, CD8, CD45RO, CD28, CD95, CCR7, Live/Dead Aqua, dump channel-CD19, CD14, CD56, CD16) that can successfully identify six distinct CD4 and CD8 T cell populations within the naïve and effector cell subsets from human donors.

Overview of Paediatric Bone and Joint Infections

Paediatric bone and joint infections are common, and can be challenging to diagnose due to significant variation in the signs and symptoms depending on the age of the patient, site of infection and causative organism. Both septic arthritis and osteomyelitis are common, often co-existing. Surgeons must have a consistent approach to investigation and management of these patients to minimise morbidity from unrecognised or undertreated infection. We provide an overview of the epidemiology, presentation, investigation and management of both septic arthritis and osteomyelitis in children.

Distribution of HIV Self-tests by HIV-Positive Men Who Have Sex with Men to Social and Sexual Contacts.

HIV-positive men who have sex with men (MSM) were recruited on www.Facebook.com and www.Poz.com to give HIV self-tests to their contacts. Study participants completed a baseline survey, were given two self-tests, and completed a survey 2months later. Of 133 eligible men, 40 (30%) completed both surveys. Most participants were 30-54years old and non-Hispanic white. Some had a detectable viral load (n = 4), had condomless anal sex with male partners of negative or unknown status (n = 17), and had met anal sex partners at gay dating websites (n = 23). Of 80 self-tests given to participants, 59 (74%) were distributed, primarily to non-Hispanic white MSM, 30-54years old who were friends. Participants reported results from 31 distributed tests; 2 sex partners of participants had positive results. Participants indicated these two persons were unaware of their infections. Expanding recruitment websites might reach non-white MSM. Unrecognized infections were identified through online recruitment and self-test distribution via HIV-positive persons.

PrEParing for the Unexpected: Mechanisms and Management of HIV pre-exposure Prophylaxis Failure

Pre-exposure prophylaxis (PrEP) for HIV is a proven and effective tool for preventing HIV. However, there are instances where individuals taking PrEP have contracted HIV infection. Most of these cases are due to nonadherence to the drug, while other cases of apparent PrEP failure are due to unrecognized HIV infection at baseline. Importantly, there are also now at least three well-documented cases of PrEP failing despite adequate adherence; these are cases of PrEP ‘breakthrough’. This article outlines the potential mechanisms of PrEP failure, as well as how to identify and manage these patients. Finally, we provide a perspective on the future of PrEP as a key tool in preventing HIV worldwide.

Microbial community profiling of peripheral blood in myalgic encephalomyelitis/chronic fatigue syndrome

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is estimated to afflict hundreds of thousands, if not millions, of Americans with vastly more impacted individuals worldwide; however, the etiology of this disease has not been well established. Based on the features of ME/CFS, we hypothesized an unrecognized vascular infection may be involved. To evaluate this possibility, we performed a blinded pilot study of 30 ME/CFS patients meeting the Fukuda criteria and 48 normal controls. A community-wide analysis using next-generation DNA sequencing methods detected prokaryotic and eukaryotic populations in the peripheral blood of both ME/CFS patients and normal controls. Analysis of the prokaryotic portion of the samples revealed that organisms belonging to the Pseudomonas asplenii species, Pseudomonadaceae family, Pseudomonadales order, and γ-proteobacteria class are inversely correlated with RAND-36 scores, a quality of life metric that is reduced in ME/CFS patients. In addition, analysis of the detected eukaryotic species suggests that the Perkinsus genus is also inversely associated with RAND-36 scores. The most frequently observed eukaryotic DNA was for Funneliformis mosseae, an arbuscular mycorrhizal fungus, which was in both ME/CFS and normal control samples. A multivariate composite score consisting of the Perkinsus genus, Spumella genus, and β-proteobacteria class displays an inverse relationship to RAND-36 scores. Lastly, the combined measurements of several taxa allow for a retrospective categorical sorting of ME/CFS patients from normal control samples. These results suggest that microbial DNA signatures, including those from poorly understood eukaryotes, may be differentially detectable in ME/CFS and normal control samples.

Interpretation of tuberculosis and hepatitis screening before immunosuppressive treatment

An unrecognized latent tuberculosis infection (LTBI) may be reactivated under immunosuppressive therapy and become life threatening. Diagnosing LTBI requires the combination of targeted patient history and physical examination with the results of an interferon-gamma release assay (IGRA) and in addition, achest X‑ray is needed to rule out active tuberculosis. Established therapies for LTBI reduce the reactivation risk by approximately 80%. For the initial screening of an HBV infection HBsAg and anti-HBc are determined. Hereby, HBsAg carriers (high HBV reactivation risk, indications for antiviral prophylaxis) and serologically resolved HBV infections (low HBV reactivation risk, use of prophylaxis only in high-risk immunosuppression) can be reliably detected. Apreviously unrecognized HCV infection, with an increased risk of developing liver cirrhosis during immunosuppression, can be detected in screening by anti-HCV antibodies and be successfully treated with antivirals without interferon.

Neurological syndromes driven by postinfectious processes or unrecognized persistent infections.

The immune system serves a critical role in protecting the host against various pathogens. However, under circumstances, once triggered by the infectious process, it may be detrimental to the host. This may be as a result of nonspecific immune activation or due to a targeted immune response to a specific host antigen. In this opinion piece, we discuss the underlying mechanisms that lead to such an inflammatory or autoimmune syndrome affecting the nervous system. We examine these hypotheses in the context of recent emerging infections to provide mechanistic insight into the clinical manifestations and rationale for immunomodulatory therapy. Some pathogens endure longer than previously thought. Persistent infections may continue to drive immune responses resulting in chronic inflammation or development of autoimmune processes, resulting in damage to the nervous system. Patients with genetic susceptibilities in immune regulation may be particularly vulnerable to pathogen driven autoimmune responses. The presence of prolonged pathogens may result in chronic immune stimulations that drives immune-mediated neurologic complications. Understanding the burden and mechanisms of these processes is challenging but important.

Identification of tick-borne pathogen diversity by metagenomic analysis in Haemaphysalis longicornis from Xinyang, China

BackgroundA wide variety of pathogens could be maintained and transmitted by Haemaphysalis longicornis. The aim of this study is to systematically examine the variety of pathogens carried by Haemaphysalis longicornis, an importnatn vector, in tick-borne diseases epidemic area, and to estimate the risk of human infection imposed by tick bites.MethodsAdult questing ticks were collected in Xinyang, central China. Genomic DNA and RNA were extracted from 144 H. longicornis ticks individually, and sequenced respectively as the templates for high-throughput sequencing. Clean reads were compared against the database of NCBI nucleotide collection and specific PCR was performed to confirm the presence of pathogen. Phylogenetic analysis was performed to explore the evolutionary status of pathogens.ResultsThe assignment of reads to taxa based on BLASTN results revealed the existence of several potential pathogens, including Anaplasma spp., Rickettsia spp., Babesia sp., as well as severe fever with thrombocytopenia syndrome bunyavirus (SFTSV). Comfirmantory PCR assays revealed the existence of Anaplasma bovis (13/144, 9.03%), Anaplasma centrale (2/144, 1.39%), Rickettsia heilongjiangensis (3/144, 2.08%), Rickettsia sp. LON-13 (1/144, 0.69%), Rickettsia raoultii (5/144, 3.47%), Babesia sp. (1/144, 0.69%). SFTSV accounted for the highest detected pathogen with a positive rate of 18.75% (27/144). Three of the ticks (2.08%) were co-infected with SFTSV and A. bovis.ConclusionOur study provided a broadened list of microorganism that harbored by H. longicornis. In previously unrecognized endemic regions, prokaryotic and eukaryotic infection including Anaplasma spp., Rickettsiae spp., and Babesia spp. should be considered, along with the well-known SFTSV for patients with tick bites history. A novel Babesia species was identified in local natural foci, which needs further investigation in the future.

A Good Therapeutic Strategy to Unrecognized HIV Infection in A Patient with Multiple Myeloma Undergoing Peripheral Blood Stem Cell Transplantation - Case Report

Multiple myeloma is a hematological malignancy associated with increased plasma cell proliferation in the patient's bone marrow. HIV infection is an immunodeficiency disease that is present in some malignancies, such as non-Hodgkin's lymphomas, as an effective factor in the progression of malignancy. Our patient was diagnosed with multiple myeloma and after bone marrow transplantation, it became clear that the patient was HIV positive and also, he had a mild toxoplasmosis infection. After diagnosis, the patient was treated with antiviral drugs and drugs for the treatment of toxoplasma infection. After several months and carrying out the relevant tests, it indicates the control of HIV viral infection, and the patient is still being treated and followed up. Nonetheless, our case features the significance of HIV testing in early malignancy.

Primary Prenatal Care: Screening, Prevention, and Treatment of Viral Infections.

Prenatal care providers are responsible for a basic understanding of the viral contagions that place women and fetal well-being at risk during pregnancy. This article reviews the evidence-based routine prenatal screening guidelines for previously unrecognized maternal infection, counseling toward risk reduction, recommended maternal immunizations, and the management of maternal and fetal complications of some viral exposures and infections.

Seroprevalence of Pertussis in Healthcare Workers without Adult Pertussis Vaccine Use at a University Hospital in Korea.

BackgroundPertussis is highly contagious respiratory disease. Healthcare workers (HCWs) can be an important mediator of the disease. A seroprevalence of pertussis was investigated in HCWs to determine the immune status against pertussis and to detect the unidentified pertussis.MethodsThis study was conducted for HCWs at a hospital located in Korea in 2011. After obtaining written informed consent for HCWs voluntarily participating in the study, 10 mL of blood was collected from each subject. Demographic and medical data were collected using questionnaire. Data on the underlying disease and vaccination history were reviewed again through medical records. The presence of anti-pertussis toxin (anti-PT) immunoglobulin G (IgG), and immunoglobulin A (IgA) was detected by quantitative analysis using a commercially available ELISA kit (EUROIMMUN, Lübeck, Germany).ResultsA total of 412 HCW participated in the study. Among them, 14 were excluded due to the inadequate sample amount or medical history not secured. Of the 398 HCWs analyzed, 16.6% (66/398) were men and the mean age was 33.82 ± 9.10 years (range, 21–67). The mean anti-PT IgG titer was 8.32 ± 20.40 IU/mL (range, 0.4–287.5 IU/mL). The overall seroprevalence (rate of anti-PT IgG antibody [Ab] titer > 5 IU/mL) was 33.7%. Three (0.8%) HCWs had the Ab level > 100 IU/mL indicated acute infection. There was no statistically significant difference in the seroprevalence and mean titer of anti-PT IgG Ab according to age group, type of occupation, patient-facing position, or working in the pediatric department.ConclusionThe seroprevalence of pertussis of the HCWs of a university hospital in Korea was low, and there were some unrecognized acute infections. Therefore, booster immunization of pertussis to HCWs should be actively considered.

Unrecognized Dengue Virus Infections in Children, Western Kenya, 2014-2015.

We detected a cluster of dengue virus infections in children in Kenya during July 2014–June 2015. Most cases were serotype 1, but we detected all 4 serotypes, including co-infections with 2 serotypes. Our findings implicate dengue as a cause of febrile illness in this population and highlight a need for robust arbovirus surveillance.

Assessment and Translation of the Antibody-in-Lymphocyte Supernatant (ALS) Assay to Improve the Diagnosis of Enteric Fever in Two Controlled Human Infection Models and an Endemic Area of Nepal.

New diagnostic tests for enteric fever are urgently needed to assist with timely antimicrobial treatment of patients and to measure the efficacy of prevention measures such as vaccination. In a novel translational approach, here we use two recently developed controlled human infection models (CHIM) of enteric fever to evaluate an antibody-in-lymphocyte supernatant (ALS) assay, which can detect recent IgA antibody production by circulating B cells in ex vivo mononuclear cell culture. We calculated the discriminative ability of the ALS assay to distinguish diagnosed cases in the two CHIM studies in Oxford, prior to evaluating blood culture-confirmed diagnoses of patients presenting with fever to hospital in an endemic areas of Kathmandu, Nepal. Antibody responses to membrane preparations and lipopolysaccharide provided good sensitivity (>90%) for diagnosing systemic infection after oral challenge with Salmonella Typhi or S. Paratyphi A. Assay specificity was moderate (~60%) due to imperfect sensitivity of blood culture as the reference standard and likely unrecognized subclinical infection. These findings were augmented through the translation of the assay into the endemic setting in Nepal. Anti-MP IgA responses again exhibited good sensitivity (86%) but poor specificity (51%) for detecting blood culture-confirmed enteric fever cases (ROC AUC 0.79, 95%CI 0.70–0.88). Patients with anti-MP IgA ALS titers in the upper quartile exhibited a clinical syndrome synonymous with enteric fever. While better reference standards are need to assess enteric fever diagnostics, routine use of this ALS assay could be used to rule out infection and has the potential to double the laboratory detection rate of enteric fever in this setting over blood culture alone.

Unrecognized viral infections and chromosome abnormalities as a cause of fetal death - examination with fluorescence insitu hybridization, immunohistochemistry and polymerase chain reaction.

Fifteen to 50% of fetal deaths remain unexplained after post-mortem examination depending on inclusion criteria and classification systems. Our aim was to examine a selection of unexplained fetal deaths in order to investigate whether any common chromosome aberrations or viral infections were present. Reports from 351 fetal autopsies performed at the Department of Pathology and Medical Genetics at St. Olavs University Hospital from 2001 through 2010 were reviewed. Of these, 105 fetal deaths were classified as unexplained. Tissue samples from 30 cases were further examined with fluorescence insitu hybridization (FISH) to detect abnormalities in chromosomes 13, 18, and 21. The samples were also examined with immunohistochemistry (IHC) and polymerase chain reaction (PCR) to detect infections with cytomegalovirus, parvovirus B19, herpes simplex virus 1 and 2, enterovirus, and parechovirus. In two cases, a possible trisomy 13 mosaicism was found. No viruses were detected. In our selection of 30 unexplained cases, possible trisomy 13 mosaicism was found in two cases, and no viruses were detected. High degree of maceration and missing placental examination often complicate the investigation of fetal death, and extensive ancillary examinations do not necessarily contribute to a more specific diagnosis.

Sex with older partners, condomless anal sex and unrecognized HIV infection among Chinese men who have sex with men

ABSTRACTWe examined the prevalence of sex with older male partner (SWOMP) and its association with condomless anal intercourse (CAI) with male partners and unrecognized HIV infection among young men who have sex with men (MSM) in Shanghai, China. The analytic sample included 243 MSM who were 18–45 years and HIV negative or of unknown HIV serostatus. Older male partner refers to male sex partner who was at least 10 years older than themselves. Overall, 99 (43.0%) and 50 (20.7%) reported having SWOMP in lifetime and in the last 3 months, respectively. Having any CAI with male partners in the last 3 months was independently associated with SWOMP and sex with stable male partners in the last 3 months. Unrecognized HIV infection was independently associated with being HSV-2 positive and having any CAI with male partners as well as SWOMP in last 3 months. Sex with stable male partner in the last 3 months was also marginally significantly associated with unrecognized infection (p = 0.084). Older partner selection is common among young MSM in China. Prevention programs should incorporate education messages about the HIV risk associated with SWOMP. MSM should be informed that having condomless sex with stable partners may place them at HIV risk.

Hepatitis A to E: what's new?

Viral hepatitis contributes to significant morbidity and mortality worldwide. While acute infection may be self-limiting, unrecognised chronic infection and under-utilisation of guideline-based approaches to therapy contribute to increasing rates of cirrhosis, hepatocellular carcinoma and death. Our aim was to review the current evidence for screening, diagnosis and treatment in hepatitis A to E. Evidence for this review was sourced from international and Australian guidelines and high-quality clinical trials. MEDLINE was searched using structured key word strategy and retrieved articles were reviewed methodically to inform a brief and up-to-date synopsis of hepatitis A to E. We share some of the recent developments in viral hepatitis, specifically the new therapies for hepatitis C. Direct-acting antiviral therapies are safe, well-tolerated and effective. Subsidies allow access for all Australians with most strains of hepatitis C. We outline evidence underpinning efficacy and safety of treatment for hepatitis B, while clarifying some of the nuances in the setting of pregnancy and immunosuppression. We provide a simplified concept to facilitate understanding of the five phases of hepatitis B; practical for real-world setting. Hepatitis A to E is a broad topic, not all aspects of these viruses can be covered in this short review. We provided suggestions for evidence based guidelines, which are a suitable supplement to this article.

Investigation of liver dysfunction: who should we test for hepatitis E?

Hepatitis E virus (HEV) is endemic in developed countries, but unrecognized infection is common. Many national guidelines now recommend HEV testing in patients with acute hepatitis irrespective of travel history. The biochemical definition of 'hepatitis' that best predicts HEV infection has not been established. This study aimed to determine parameters of liver biochemistry that should prompt testing for acute HEV. This was a retrospective study of serial liver function tests (LFTs) in cases of acute HEV (n=74) and three comparator groups: common bile duct stones (CBD, n=87), drug-induced liver injury (DILI, n=69) and patients testing negative for HEV (n=530). To identify the most discriminating parameters, LFTs from HEV cases, CBD and DILI were compared. Optimal LFT cutoffs for HEV testing were determined from HEV true positives and HEV true negatives using receiver operating characteristic curve analysis. Compared with CBD and DILI, HEV cases had a significantly higher maximum alanine aminotransferase (ALT) (P<0.001) and ALT/alkaline phosphatase (ALKP) ratio (P<0.001). For HEV cases/patients testing negative for HEV, area under receiver operating characteristic curve was 0.805 for ALT (P<0.001) and 0.749 for the ALT/ALKP ratio (P<0.001). Using an ALT of at least 300 IU/l to prompt HEV testing has a sensitivity of 98.6% and a specificity of 30.3% compared with an ALT/ALKP ratio higher than or equal to 2 (sensitivity 100%, specificity 9.4%). Patients with ALT higher than or equal to 300 IU/l should be tested for HEV. This is simple, detects nearly all cases and requires fewer samples to be tested than an ALT/ALKP ratio higher than or equal to 2. Where clinically indicated, patients with an ALT less than 300 IU/l should also be tested, particularly if HEV-associated neurological injury is suspected.

Sero-epidemiologic study of influenza A(H7N9) infection among exposed populations, China 2013-2014.

BackgroundThe first human infections of novel avian influenza A(H7N9) virus were identified in China in March 2013. Sentinel surveillance systems and contact tracing may not identify mild and asymptomatic human infections of influenza A(H7N9) virus.ObjectivesWe assessed the seroprevalence of antibodies to influenza A(H7N9) virus in three populations during the early stages of the epidemic.Patients/MethodsFrom March 2013 to May 2014, we collected sera from the general population, poultry workers, and contacts of confirmed infections in nine Chinese provinces reporting human A(H7N9) infections and, for contacts, second sera 2‐3 weeks later. We screened for A(H7N9) antibodies by advanced hemagglutination inhibition (HI) assay and tested sera with HI titers ≥20 by modified microneutralization (MN) assay. MN titers ≥20 or fourfold increases in paired sera were considered seropositive.ResultsAmong general population sera (n=1480), none were seropositive. Among poultry worker sera (n=1866), 28 had HI titers ≥20; two (0.11%, 95% CI: 0.02‐0.44) were positive by MN. Among 61 healthcare and 117 non‐healthcare contacts’ sera, five had HI titers ≥20, and all were negative by MN. There was no seroconversion among 131 paired sera.ConclusionsThere was no evidence of widespread transmission of influenza A(H7N9) virus during March 2013 to May 2014, although A(H7N9) may have caused rare, previously unrecognized infections among poultry workers. Although the findings suggest that there were few undetected cases of influenza A(H7N9) early in the epidemic, it is important to continue monitoring transmission as virus and epidemic evolve.

From Internal Wards to Intensive Care Units and backwards: the paths of the difficult patient

Sepsis-induced organ dysfunction may be occult; therefore, its presence should be considered in any patient presenting with infection. Conversely, unrecognized infection may be the cause of new-onset organ dysfunction. Any unexplained organ dysfunction should thus raise the possibility of underlying infection. Severe sepsis is a heterogeneous clinical entity with a wide spectrum of manifestations and severity, and over half of patients never receive care in an Intensive Care Unit (ICU). Due to ageing of the population, patients with severe sepsis are frequently admitted to general wards and, given the standard diagnostic approach, treatment must be tailored to the single patient, taking into account the burden of comorbidities. From Internal Medicine Wards the single patient could be transferred to ICU, but again admitted to our Units, due to his/her frailty, to complete the path of cure. First of all, we have to be aware of the illness and more, according to the recent literature, that, generally speaking, limits invasiveness, to be able to take care of this kind of patients.

Fever in an Adult with Sickle Cell Disease: To Treat or Not to Treat? A Case of Multi-Organ Failure

Patients with sickle cell disease are at increased risk of invasive infection despite gains made through penicillin prophylaxis, pneumococcal immunization and newborn screening. We present the case of a 42-year old male with hemoglobin SS disease, who developed acute multi-organ failure (MOF) secondary to Streptococcus pyogenes. He presented to the emergency department complaining of fever three times in five days, although a febrile at each presentation. On his third visit he became hemodynamically unstable and encephalopathic requiring intubation and admission to the ICU. His course was complicated by cardiomyopathy, acute renal insufficiency and bilateral trans metatarsal amputations. He was successfully discharged home on hospital day #37. We report on our experience with MOF from unrecognized infection in an adult with SCD, fever and review evidence-based and consensus treatment practices for management of sickle disease and fever in the emergency department. In conclusion, we strongly recommend that all fever in adults with sickle cell disease be treated as a medical emergency and receive empiric antibiotic therapy in addition to routine work-up and investigations.