Influenza and rhinovirus viral load and disease severity in upper respiratory tract infections

BackgroundThe role of viral load in respiratory viral infection is unclear. It is proposed that the viral load of some, but not all respiratory viruses correlate with disease severity.ObjectivesWe aimed to determine if an association exists between viral loads among patients in ambulatory settings, compared to those requiring hospitalization/intensive care unit (ICU) admission with influenza A/H3N2, influenza B, or human rhinovirus (HRV); we also explored the impact of age, gender and co-detection of Streptococcus pneumoniae on patient setting. We hypothesized that hospitalized/ICU patients have higher respiratory virus viral loads compared to ambulatory (e.g. walk-in clinics, family practices)/ER patients.Study designWe quantified viral load by in-house real-time RT-PCR in 774 nasopharyngeal swabs with influenza A/H3N2, or B or HRV viruses from various patient settings in Ontario, Canada.ResultsMean viral load (log₁₀ copies/ml) of influenza A/H3N2 (6.94) was higher than influenza B (4.96) and HRV (5.58) (p < 0.0001). Influenza A/H3N2 viral loads were highest in infants and the elderly; however, increased A/H3N2 viral loads were not associated with hospitalization/ICU admission compared to swabs collected in ambulatory/ER settings. Influenza B viral loads were higher in patients in hospital/ICU settings compared to those in ambulatory settings (OR 1.28, 95% CI 1.11–1.47). HRV viral loads did not differ by age (p = 0.67) or setting (p = 0.54); there was no association between S. pneumoniae colonization and setting for any virus.ConclusionWhen compared to ambulatory/ER patients, viral load was higher in hospitalized/ICU patients with influenza B, but not influenza A or HRV.     

Epidemiologic,clinical, and virologic characteristics of human rhinovirus infection among otherwise healthy children and adults: Rhinovirus among adults and children

Backgroundhuman rhinovirus (HRV) is a major cause of influenza-like illness (ILI) in adults and children. Differences in disease severity by HRV species have been described among hospitalized patients with underlying illness. Less is known about the clinical and virologic characteristics of HRV infection among otherwise healthy populations, particularly adults.Objectivesto characterize molecular epidemiology of HRV and association between HRV species and clinical presentation and viral shedding.Study designobservational, prospective, facility-based study of ILI was conducted from February 2010 to April 2012. Collection of nasopharyngeal specimens, patient symptoms, and clinical information occurred on days 0, 3, 7, and 28. Patients recorded symptom severity daily for the first 7 days of illness in a symptom diary. HRV was identified by RT-PCR and genotyped for species determination. Cases who were co-infected with other viral respiratory pathogens were excluded from the analysis. We evaluated the associations between HRV species, clinical severity, and patterns of viral shedding.Resultseighty-four HRV cases were identified and their isolates genotyped. Of these, 62 (74%) were >18 years. Fifty-four were HRV-A, 11HRV-B, and 19HRV-C. HRV-C infection was more common among children than adults (59% vs. 10%, P < 0.001). Among adults, HRV-A was associated with higher severity of upper respiratory symptoms compared to HRV-B (P = 0.02), but no such association was found in children. In addition, adults shed HRV-A significantly longer than HRV-C (P trend = 0.01).Conclusionsamong otherwise healthy adults with HRV infection, we observed species-specific differences in respiratory symptom severity and duration of viral shedding.     

Persistent rhinovirus infection in pediatric hematopoietic stem cell transplant recipients with impaired cellular immunity

BackgroundHRV infections are generally self-limiting in healthy subjects, whereas in immunocompromised hosts HRV infections can lead to severe complications and persistent infections. The persistence of HRV shedding could be due to the inefficient immunological control of a single infectious episode.ObjectivesTo investigate the clinical, virologic and immunologic characteristics of pediatric HSCT recipients with HRV-PI infection.Study designDuring the period 2006–2012, eight hematopoietic stem cell transplant (HSCT) recipients presented with persistent rhinovirus infection (HRV-PI, ≥30 days). Viral load and T-CD4⁺, T-CD8⁺, B and NK lymphocyte counts at the onset of infection were compared with those of fourteen HSCT recipients with acute HRV infection (HRV-AI, ≤15 days).ResultsThe median duration of HRV positivity in patients with HRV-PI was 61 days (range 30–174 days) and phylogenetic analysis showed the persistence of a single HRV type in all patients (100%). In HSCT recipients with HRV-PI, T-CD4⁺, T-CD8⁺ and NK cell counts at the onset of infection were significantly lower than those observed in recipients with HRV-AI (p < 0.01), while B cell counts were similar in the two groups (p =  0.25). A decrease in HRV load was associated with a significant increase in T-CD4⁺, T-CD8⁺and NK lymphocyte counts in HRV-PI patients (p < 0.01).ConclusionsThis study suggests a role for cellular immunity in HRV clearance and highlights the importance of its recovery for the control of HRV infection in HSCT recipients.     

鼻病毒在婴幼儿下呼吸道感染中作用的研究

目的探讨鼻病毒在婴幼儿下呼吸道感染中的作用。方法收集2008年5月到2009年4月北京儿童医院下呼吸道感染住院儿童鼻咽分泌物标本240份,使用Real-timeRT-PCR方法筛选鼻病毒阳性标本,并进行统计分析。结果在240例住院儿童中,入院诊断为肺炎的208例,占86．67％（208／240）,支气管炎21例（8．14％）,毛细支气管炎11例,无死亡病例,男女病例比例为1．93：1,且2009年2月采集标本数达到最多。采用Real-timeRT-PCR方法检测为鼻病毒阳性的标本71份,阳性率为29．58％（71／240）,且主要的临床诊断症状是肺炎。发病年龄以2岁以下婴幼儿为主,占81．69％（58／71）,其中以13～18月、324月年龄组发病率最高,发病率为33．33％。结论鼻病毒感染季节为春季和冬季,尤以2岁以下婴幼儿感染为主,主要症状表现为肺炎、支气管炎及毛细支气管炎等下呼吸道感染。鼻病毒流行具有季节性,且传染性强,传播速度快,应做好医院内防护措施,避免交叉感染。     

Successful treatment of Talaromyces marneffei infection in a kidney transplant recipient with voriconazole followed by itraconazole for the first time

Talaromyces (Penicillium) marneffei (T. marneffei) is an important pathogenic thermally dimorphic fungus in Southeast Asia that leads to a life-threatening systemic mycosis in immunodeficient hosts, especially in AIDS patients. With the increasing AIDS epidemic, the number of patients with T. marneffei infections in mainland China has increased rapidly in recent years. The infection can be life-threatening in people with immunodeficiencies, such as HIV, organ transplantations, autoimmune diseases, and malignant tumors. Here, we present a disseminated T. marneffei infection case in a renal transplant recipient successfully treated with voriconazole followed by itraconazole. We describe the patient's clinical progression from onset symptoms to recovery and review the additional 14 published cases with T. marneffei infections in renal transplant recipients. In addition, we discuss the route of infection and treatment strategies of T. marneffei. Our data suggest that patients with kidney transplantations in T. marneffei infection-endemic areas should presume the possibility of infection and initiate appropriate antifungal treatment.     

Detection of human rhinoviruses in the lower respiratory tract of lung transplant recipients

The occurrence of human rhinoviruses (HRV) and its relationship to clinical and histopathological findings were investigated in 127 bronchoalveolar lavage specimens from 36 lung transplant recipients by real-time RT-PCR. In addition, 286 samples from 235 other immunocompromised and immunocompetent patients were also studied. HRV was detected in 41.7% of lung transplant recipients vs 14.5% of other patients (p < 0.0001), and no differences in viral load were observed. Acute respiratory insufficiency was found in 15 cases, three of which were HRV positive (viral load, 6.3x10⁶ RNA copies/ml in one patient with chronic graft dysfunction). A diagnosis of pneumonia was made in 10 out of 127 cases, two of which were HRV positive (viral load, 10³-10⁴ in cases of co-infection). Acute rejection was diagnosed in 12 cases, three of which were HRV positive (viral load, 10³ in two cases of co-infection and 10⁵ in a single infection). HRV infection may involve the lower respiratory tract, particularly in the presence of an impaired pulmonary background, such as a transplanted lung. Clinical evaluation should take into account the viral load, with a load of >10⁵ possibly being associated with clinical symptoms, although lower loads can be detected in both symptomatic and asymptomatic patients.     

Impact of human metapneumovirus and human cytomegalovirus versus other respiratory viruses on the lower respiratory tract infections of lung transplant recipients

Viral respiratory tract infections in lung transplant recipients may be severe. During three consecutive winter-spring seasons, 49 symptomatic lung transplant recipients with suspected respiratory viral infection, and 26 asymptomatic patients were investigated for presence of respiratory viruses either in 56 nasopharyngeal aspirate or 72 bronchoalveolar lavage samples taken at different times after transplantation. On the whole, 1 asymptomatic (3.4%) and 28 symptomatic (57.1%) patients were positive for human metapneumovirus (hMPV, 4 patients), influenza virus A (3 patients), and B (2 patients), respiratory syncytial virus (2 patients), human coronavirus (2 patients), human parainfluenza virus (2 patients), rhinovirus (5 patients), while 4 patients were coinfected by 2 respiratory viruses, and 5 were infected sequentially by 2 or more respiratory viruses. In bronchoalveolar lavage samples, hMPV predominated by far over the other viruses, being responsible for 60% of positive specimens, whereas other viruses were present in nasopharyngeal aspirates at a comparable rate. RT-PCR (detecting 43 positive samples/128 examined) was largely superior to monoclonal antibodies (detecting 17 positive samples only). In addition, HCMV was detected in association with a respiratory virus in 4/18 HCMV-positive patients, and was found at a high concentration (>10(5) DNA copies/ml) in 3/16 (18.7%) patients with HCMV-positive bronchoalveolar lavage samples and pneumonia. Coinfections and sequential infections by HCMV and respiratory viruses were significantly more frequent in patients with acute rejection and steroid treatment. In conclusion: (i) about 50% of respiratory tract infections of lung transplant recipients were associated with one or more respiratory viruses; (ii) hMPV largely predominates in bronchoalveolar lavage of symptomatic lung transplant recipients, thus suggesting a causative role in lower respiratory tract infections; (iii) RT-PCR appears to be the method of choice for detection of respiratory viruses in lung transplant recipients, (iv) a high HCMV load in bronchoalveolar lavage is a risk factor for viral pneumonia, suggesting some measure of intervention for the control of viral infection.     

Colonization and infection due to carbapenemase-producing Enterobacteriaceae in liver and lung transplant recipients and donor-derived transmission: a prospective cohort study conducted in Italy

Objectives

A prospective cohort study was conducted in Italy in order to describe the microbiologic aspects of colonization/infection by carbapenemase-producing Enterobacteriaceae (CPE) in donors and recipients of lung and liver transplants and the possible CPE transmission from donors to recipients.

儿童急性呼吸道博卡病毒感染的病毒载量与临床特征相关性研究

目的 研究急性呼吸道感染患儿人博卡病毒（ human bocavirus,H BoY）病毒载量与临床特征的相关性。方法 对2009年l1月至2010年12月间956例呼吸道感染的患儿及251例健康对照组儿童鼻咽部抽吸物、咽拭子采用PCR法进行HBoV检测,进而对阳性样本进行实时荧光定量PCR法测定博卡病毒DNA载量,并结合患儿的临床检查进行综合分析。结果 实验组与对照组HBoV阳性率存在显著差异,下呼吸道感染病例HBoV的病毒载量水平与上呼吸道感染病例及对照组儿童差异均有统计学意义,上呼吸道感染病例与对照组儿童病毒载量无统计学意义,重症下呼吸道感染患儿与普通下呼吸道感染患儿HBoV的病毒载量无统计学差异,HBoV混合感染与独立感染患儿病毒载量亦无统计学差异。结论 博卡病毒常年均可引起发病,是儿童呼吸道感染的重要病原体之一,但可能不是儿童急性呼吸道感染的唯一因素。HBoV病毒载量并不能独立反映临床疾病感染的严重程度。     

Clinical and molecular epidemiology of human rhinovirus infections in patients with hematologic malignancy

BackgroundHuman rhinoviruses (HRVs) are common causes of upper respiratory tract infection (URTI) in hematologic malignancy (HM) patients. Predictors of lower respiratory tract infection (LRTI) including the impact of HRV species and types are poorly understood.ObjectivesThis study aims to describe the clinical and molecular epidemiology of HRV infections among HM patients.Study designFrom April 2012–March 2013, HRV-positive respiratory specimens from symptomatic HM patients were molecularly characterized by analysis of partial viral protein 1 (VP1) or VP4 gene sequence. HRV LRTI risk-factors and outcomes were analyzed using multivariable logistic regression.ResultsOne hundred and ten HM patients presented with HRV URTI (n = 78) and HRV LRTI (n = 32). Hypoalbuminemia (OR 3.0; 95% CI, 1.0–9.2; p = 0.05) was independently associated with LRTI, but other clinical and laboratory markers of host immunity did not differ between patients with URTI versus LRTI. Detection of bacterial co-pathogens was common in LRTI cases (25%). Among 92 typeable respiratory specimens, there were 58 (64%) HRV-As, 12 (13%) HRV-Bs, and 21 (23%) HRV-Cs, and one Enterovirus 68. LRTI rates among HRV-A (29%), HRV-B (17%), and HRV-C (29%) were similar. HRV-A infections occurred year-round while HRV-B and HRV-C infections clustered in the late fall and winter.ConclusionsHRVs are associated with LRTI in HM patients. Illness severity is not attributable to specific HRV species or types. The frequent detection of bacterial co-pathogens in HRV LRTIs further substantiates the hypothesis that HRVs predispose to bacterial superinfection of the lower airways, similar to that of other community-acquired respiratory viruses.     

先天性HCMV感染新生儿尿液中病毒载量与疾病严重度的关系探讨

目的探讨新生儿尿液中人巨细胞病毒（HCMV）病毒载量与先天性感染的关系及与HCMV所致疾病严重程度的关系。方法采集98例经PCR方法确诊的有症状及无症状的先天性HCMV感染新生儿尿液标本,用实时荧光定量PCR法（FQ—PCR）检测尿液中巨细胞病毒载量。结果98例先天性HCMV感染的新生儿中85例在出生后有临床症状（86％）。无症状感染和有症状感染的新生儿尿液中平均HCMV病毒载量分别是1．4×10^5拷贝／ml和3．1×10^6拷贝／ml,P〈0．01,差异有统计学意义。结论先天性HCMV感染的新生儿中无症状感染者尿液中病毒载量显著低于有症状感染者,提示病毒载量与疾病严重程度相关。     

Impact of rhinovirus nasopharyngeal viral load and viremia on severity of respiratory infections in children

There are few and partially discordant data regarding nasopharyngeal rhinovirus (RV) load and viremia, and none of the published studies evaluated the two variables together. The aim of this study was to provide new information concerning the clinical relevance of determining nasopharyngeal viral load and viremia when characterising RV infection. Nasopharyngeal swabs were obtained from 251 children upon their admission to hospital because of fever and signs and symptoms of acute respiratory infection in order to identify the virus and determine its nasopharyngeal load, and a venous blood sample was taken in order to evaluate viremia. Fifty children (19.9 %) had RV-positive nasopharyngeal swabs, six (12 %) of whom also had RV viremia: RV-C in four cases (66.6 %), and RV-A and RV-B in one case each. The RV nasopharyngeal load was significantly higher in the children with RV viremia (p?<?0.001), who also had a higher respiratory rate (p?=?0.02), white blood cell counts (p?=?0.008) and C-reactive protein levels (p?=?0.006), lower blood O₂ saturation levels (P?=?0.005), and more often required O₂ therapy (p?=?0.009). The presence of RV viremia is associated with a significantly higher nasopharyngeal viral load and more severe disease, which suggests that a high nasopharyngeal viral load is a prerequisite for viremia, and that viremia is associated with considerable clinical involvement.     

Bronchioloalveolar lavage in the diagnosis of CMV pneumonitis in lung transplant recipients: An immunocytochemical study

Cytomegalovirus (CMV) pneumonitis is a common opportunistic infection in lung transplant recipients. Its diagnosis usually rests on the identification of viral inclusions in lung parenchyma obtained by transbronchial biopsy, or by examination of the cytologic material obtained by bronchioloalveolar lavage (BAL). To determine whether the use of immunocytochemistry (ICC) increases the sensitivity of cytology in the diagnosis of CMV pneumonitis, we retrospectively selected 17 cases in which transbronchial biopsy and BAL were performed simultaneously, and had positive histology with negative cytology. Five negative controls were selected. The 22 slides were decolorized and restained with ICC for CMV. Of the 17 slides, nine (53%) showed cells with positive nuclear staining. All controls were negative. These results were then correlated with the number of infected cells present in the biopsy tissue, and the location of the cells (interstitial vs. intraalveolar). A good correlation was found between positive cytology and intraalveolar location of infected cells, and no correlation was seen between number of infected cells in the biopsy and the positive cytology. In summary, although histologic evaluation of lung parenchyma obtained by transbronchial biopsy is more sensitive for diagnosis of CMV pneumonitis, the sensitivity of the cytologic evaluation of BAL material can be increased by the use of ICC. The likelihood of positive ICC seems to be related to the presence of infected cells in the alveolar space rather than to the number of infected cells. Diagn. Cytopathol. 16:350–352, 1997. © 1997 Wiley-Liss, Inc.     

Functional impairment of cytotoxic T cells in the lung airways following respiratory virus infections

We investigated the differentiation phenotype and function of virus-specific and non-specific CTL that were recruited to the lung parenchyma and the bronchoalveolar space after respiratory virus infections. Soon after virus elimination, we observed functional impairment of CTL isolated from the airways in their ability to produce IFN-gamma and TNF-alpha and to lyse target cells. Impaired cytotoxicity was due to a reduced content of granzyme B and a reduced ability to mobilize lytic granules. This impairment in effector functions (a) was largely restricted to CTL in the lung airways, (b) affected both CTL specific for the infecting virus as well as those that were recruited non-specifically to the inflamed lung, (c) was independent of contact between CTL and their specific viral antigen, (d) was not restricted to terminally differentiated CTL but also affected resting memory CTL and (e) could be elicited by both respiratory syncytial virus and influenza virus and thus seemed to be largely independent of the infecting virus. These observations suggest that functional impairment of antiviral T cells in the lung is not the consequence of a viral escape strategy. It may rather result from the particular milieu in the bronchoalveolar space and reflect a host mechanism to prevent excessive pulmonary inflammation.     

Rotavirus infection of the oropharynx and respiratory tract in young children.

Oropharyngeal aspirates were obtained from 89 infants hospitalized with respiratory illnesses accompanied or not by diarrhea and 33 control patients without the diseases. Rotavirus was detected from 25 of these patients by immunocytology, isolation of the virus in cultures of MA104 cells, or both. None of the control patients gave a positive result. The infection involves squamous cells and globlet cells probably originating from the oropharynx, and ciliated columnar epithelial cells from the respiratory tract. The virus from 2 specimens was propagated by repeatedly passaging in the cultures and found to have characteristic morphology of rotavirus. The electrophoretic patterns of the viral RNA extracted from them are closely similar to those obtained with the rotavirus genome extracted from the stool of the same patients. Repeated stool specimens were also obtained, and sera were paired from some of these subjects. All but one of the patients who gave a positive virology for their aspirates also showed a significant rise in the titres of common group A rotavirus antibody, neutralizing antibody against one or more of serotypes of rotavirus, or both. Patients who excreted rotavirus in their stools were younger and had significantly lower titres of rotavirus antibodies in their acute sera, than those who shedded the virus in the oropharynx but did not excrete the virus in repeated stool specimens. The prevalence of rotavirus in the oropharyngeal aspirates from these patients surpassed that of adenovirus, respiratory syncytial virus, influenza virus, and herpes simplex virus combined.     

Cytomegalovirus load at treatment initiation is predictive of time to resolution of viremia and duration of therapy in hematopoietic cell transplant recipients

BackgroundPreemptive antiviral therapy relies on viral load measurements and is the mainstay of cytomegalovirus (CMV) prevention in hematopoietic cell transplant (HCT) recipients. However, optimal CMV levels for the initiation of preemptive therapy have not been defined.ObjectivesThe objectives of our work were to evaluate the relationship between plasma CMV DNA levels at initiation of preemptive therapy with time to resolution of viremia and duration of treatment.Study designRetrospective analysis of HCT recipients undergoing serial CMV PCR testing between June 2011 and June 2014 was performed.Results221 HCT recipients underwent preemptive therapy for 305 episodes of CMV viremia. Median time to resolution was shorter when treatment was initiated at lower CMV levels (15 days at 135–440 international units (IU)/mL, 18 days at 441–1000 IU/mL, and 21 days at >1000 IU/mL, P < .001). Prolonged viremia lasting >30 days occurred less frequently when treatment was initiated at 135–440 IU/mL compared to 441–1000 IU/mL and >1000 IU/mL (1%, 15%, 24%, P < .001). Median treatment duration was also shorter in the lower viral load groups (28, 34, 37 days, P < .001).ConclusionInitiation of preemptive therapy at low CMV levels was associated with shorter episodes of viremia and courses of antiviral therapy. These data support the utility of initiating preemptive CMV therapy at viral loads as low as 135 IU/mL in HCT recipients.