Single Virus Infection Research Articles

Association of specific viral infections with childhood asthma exacerbations.

IntroductionAsthma exacerbations may occur due to a variety of triggers including respiratory viruses. The aim of this study was to determine the role of particular viral infections in asthma exacerbations in children.Materials and methodsThe study was performed at Dr. Daneshvari Hospital Pediatric Emergency Department, Shahid Beheshti University of Medical Sciences, Tehran, Iran between 2014 and 2015. A nasopharyngeal aspirate or swab was obtained from each patient during admission. All samples were maintained at 4 °C until submission to the virology laboratory and were tested for respiratory viruses by nucleic acid testing.ResultsA total of 60 patients with asthma exacerbations were recruited for this study. Of the 60 samples collected from the patients with acute asthma exacerbations, rhinovirus was detected in 12 patients (20%), respiratory syncytial virus in 5 (8%), adenovirus in 5 (8%), and influenza virus in 1 (1.6%). Respiratory pathogens were not detected in 37 (61%) samples. All the samples investigated showed single viral infection.ConclusionsTo conclude, the most common viruses detected were rhinovirus followed by respiratory syncytial virus (RSV) and adenovirus. RSV was more commonly associated with more severe attacks. Both the study design (e.g., time of sampling, age of the patients, etc.) and also the method used for viral detection influence the frequency of detection of the respiratory viruses.

TLR7 polymorphism, sex and chronic HBV infection influence plasmacytoid DC maturation by TLR7 ligands

TLR7 agonists are of high interest for the treatment of cancer, auto-immunity and chronic viral infections. They are known to activate plasmacytoid dendritic cells (pDCs) to produce high amounts of Type I Interferon (IFN) and to facilitate T and B cell responses, the latter with the help of maturation markers such as CD40, CD80 and CD86. The TLR7 single nucleotide polymorphism (SNP) rs179008 (GLn11Leu), sex and chronic viral infection have all been reported to influence pDC IFN production. It is unknown, however, whether these factors also influence pDC phenotypic maturation and thereby IFN-independent pDC functions. Furthermore, it is unclear whether SNP rs179008 influences HBV susceptibility and/or clearance.Here we investigated whether the SNP rs179008, sex and HBV infection affected phenotypic maturation of pDCs from 38 healthy individuals and 28 chronic HBV patients. In addition, we assessed SNP prevalence in a large cohort of healthy individuals (n = 231) and chronic HBV patients (n = 1054).Consistent with previous reports, the rs179008 variant allele was largely absent in Asians and more prevalent in Caucasians. Among Caucasians, the SNP was equally prevalent in healthy and chronically infected males. The SNP was, however, significantly more prevalent in healthy females than in those with chronic HBV infection (42 versus 28%), suggesting that in females it may offer protection from chronic infection. Ex vivo experiments demonstrated that induction of the co-stimulatory molecules CD40 and CD86 by TLR7 ligands, but not TLR9 ligands, was augmented in pDCs from healthy SNP-carrying females. Furthermore, CD80 and CD86 upregulation was more pronounced in females independent of the SNP. Lastly, our data suggested that chronic HBV infection impairs pDC maturation. These findings provide insight into factors determining TLR7 responses, which is important for further clinical development of TLR7-based therapies.

Characterization of H5N1 Influenza Virus Quasispecies with Adaptive Hemagglutinin Mutations from Single-Virus Infections of Human Airway Cells.

Transmission of avian influenza (AI) viruses to mammals involves phylogenetic bottlenecks that select small numbers of variants for transmission to new host species. However, little is known about the AI virus quasispecies diversity that produces variants for virus adaptation to humans. Here, we analyzed the hemagglutinin (HA) genetic diversity produced during AI H5N1 single-virus infection of primary human airway cells and characterized the phenotypes of these variants. During single-virus infection, HA variants emerged with increased fitness to infect human cells. These variants generally had decreased HA thermostability, an indicator of decreased transmissibility, that appeared to compensate for their increase in α2,6-linked sialic acid (α2,6 Sia) binding specificity and/or in the membrane fusion pH threshold, each of which is an advantageous mutational change for viral infection of human airway epithelia. An HA variant with increased HA thermostability also emerged but could not outcompete variants with less HA thermostability. These results provided data on HA quasispecies diversity in human airway cells.IMPORTANCE The diversity of the influenza virus quasispecies that emerges from a single infection is the starting point for viral adaptation to new hosts. A few studies have investigated AI virus quasispecies diversity during human adaptation using clinical samples. However, those studies could be appreciably affected by individual variability and multifactorial respiratory factors, which complicate identification of quasispecies diversity produced by selective pressure for increased adaptation to infect human airway cells. Here, we found that detectable HA genetic diversity was produced by H5N1 single-virus infection of human airway cells. Most of the HA variants had increased fitness to infect human airway cells but incurred a fitness cost of less HA stability. To our knowledge, this is the first report to characterize the adaptive changes of AI virus quasispecies produced by infection of human airway cells. These results provide a better perspective on AI virus adaptation to infect humans.

Multiplex Detection of Aspergillus fumigatus Mycoviruses.

Mycoviruses are viruses that naturally infect and replicate in fungi. They are widespread in all major fungal groups including plant and animal pathogenic fungi. Several dsRNA mycoviruses have been reported in Aspergillus fumigatus. Multiplex polymerase chain reaction (PCR) amplification is a version of PCR that enables amplification of different targets simultaneously. This technique has been widely used for detection and differentiation of viruses especially plant viruses such as those which infect tobacco, potato and garlic. For rapid detection, multiplex RT-PCR was developed to screen new isolates for the presence of A. fumigatus mycoviruses. Aspergillus fumigatus chrysovirus (AfuCV), Aspergillus fumigatus partitivirus (AfuPV-1), and Aspergillus fumigatus tetramycovirus-1 (AfuTmV-1) dsRNAs were amplified in separate reactions using a mixture of multiplex primer pairs. It was demonstrated that in the presence of a single infection, primer pair mixtures only amplify the corresponding single virus infection. Mixed infections using dual or triple combinations of dsRNA viruses were also amplified simultaneously using multiplex RT-PCR. Up until now, methods for the rapid detection of Aspergillus mycoviruses have been restricted to small scale dsRNA extraction approaches which are laborious and for large numbers of samples not as sensitive as RT-PCR. The multiplex RT-PCR assay developed here will be useful for studies on determining the incidence of A. fumigatus mycoviruses. This is the first report on multiplex detection of A. fumigatus mycoviruses.

RESPIRATORY SYNCYTIAL VIRUS INFECTION OF LOWER RESPIRATORY TRACT IN HOSPITALIZED CHILDREN UNDER 1 YEAR OF LIFE

Objective: to evaluate the significance of respiratory syncytial viral infection in lower respiratory tract infections in hospitalized children 1 year of life and its features. Materials and methods: the research was carried out from march 2015 till october 2016. We enrolled all children under 1 year with acute lower respiratory tract infections. A real-time PCR method was used to detect viruses in nasopharyngeal swabs. The levels of CRP and procalcitonin were estimated. Results: We enrolled in our research 356 children with acute lower respiratory tract infections. RS-virus was detected in 129 patients (36,2%). Single viral infection was detected in 79.9% of cases. The median age of the patients was 4 (1; 7) months. 14,7% of children with RS-infection had burdened premorbid background, 16.7% of children were premature. Severe forms of RS-infection have been detected in 26.4% children. These were the children of the first months of life, the median age was 2 (1; 4) months. RS-infection proceeded mostly in the form of bronchiolitis (62%). WBC count in pneumonia and bronchiolitis associated with RSV significantly differed (10,6 against 9,2×109 /l, p 0,028). The level of CRB was 1,8 (0,5; 6,8) mg/l, procalcitonin 0,075 (0,059; 0,104) ng/ml, there was no difference in bronchiolitis and pneumonia. Conclusions: Respiratory syncytial virus infection is the leading cause of lower respiratory tract infections in hospitalized children 1 year of life. There was no increase of CRP and procalcitonin. The risk factor of severe RS- infection is early age (less than 6 months).

Respiratory viral infection`s frequency and clinical outcome in symptomatic children with cancer: A single center experience from a middle-income country.

Büyükkapu-Bay S, Kebudi R, Görgün Ö, Meşe S, Zülfikar B, Badur S. Respiratory viral infection`s frequency and clinical outcome in symptomatic children with cancer: A single center experience from a middle-income country. Turk J Pediatr 2018; 60: 653-659. In developing countries, acute respiratory tract infections are a significant cause of morbidity and mortality in children, particularly in pediatric cancer patients. A majority of these illnesses are precipitated by viral infections. In our country, studies were conducted on the single respiratory viral infection in a pediatric hematology-oncology unit; however, the analysis of respiratory viral infections in children with cancer is lacking. The present study aimed to provide analysis of multiple respiratory viral infections and clinical outcome in children with cancer who receive chemotherapy and show signs and symptoms of respiratory tract infections. During January, 2014 and January, 2015 children with cancer under treatment who presented with respiratory tract infections were assessed for viruses by using multiplex real-time reverse transcription polymerase chain reaction (rRT-PCR). Specimens were collected by nasal swabbing at in-patient and out-patient clinics. Overall, 72 samples of respiratory tract infection episodes, collected from children with cancer were evaluated with the simultaneous detection of 20 respiratory viruses. A respiratory viral pathogen was obtained in 56.9% samples. Rhinovirus (24.3%) and co-infection with two viruses (19.5%) were the most frequently isolated pathogens. There were four (9.6%) samples of severe pneumonia. Patients with febrile neutropenic episodes and pneumonia were hospitalized and treated with broad-spectrum antibiotics. Other non-neutropenic and mild respiratory tract infections were treated with supportive care as outpatient procedures. There were no deaths. Because there are no effective antiviral agents for certain respiratory viruses, infection control and early diagnosis are crucial in preventing the spread of infection. Clinical findings and serological results of viral respiratory tract infections help us to accurately determine the treatment approach and avoid the unnecessary use of antibiotics.

Clinical and laboratory profiles of hospitalized children with acute respiratory virus infection.

PurposeDespite the availability of molecular methods, identification of the causative virus in children with acute respiratory infections (ARIs) has proven difficult as the same viruses are often detected in asymptomatic children.MethodsMultiplex reverse transcription polymerase chain reaction assays were performed to detect 15 common respiratory viruses in children under 15 years of age who were hospitalized with ARI between January 2013 and December 2015. Viral epidemiology and clinical profiles of single virus infections were evaluated.ResultsOf 3,505 patients, viruses were identified in 2,424 (69.1%), with the assay revealing a single virus in 1,747 cases (49.8%). While major pathogens in single virus-positive cases differed according to age, human rhinovirus (hRV) was common in patients of all ages. Respiratory syncytial virus (RSV), influenza virus (IF), and human metapneumovirus (hMPV) were found to be seasonal pathogens, appearing from fall through winter and spring, whereas hRV and adenovirus (AdV) were detected in every season. Patients with ARIs caused by RSV and hRV were frequently afebrile and more commonly had wheezing compared with patients with other viral ARIs. Neutrophil-dominant inflammation was observed in ARIs caused by IF, AdV, and hRV, whereas lymphocyte-dominant inflammation was observed with RSV A, parainfluenza virus, and hMPV. Monocytosis was common with RSV and AdV, whereas eosinophilia was observed with hRV.ConclusionIn combination with viral identification, recognition of virus-specific clinical and laboratory patterns will expand our understanding of the epidemiology of viral ARIs and help us to establish more efficient therapeutic and preventive strategies.

Etiology and Impact of Coinfections in Children Hospitalized With Community-Acquired Pneumonia.

Recognition that coinfections are common in children with community-acquired pneumonia (CAP) is increasing, but gaps remain in our understanding of their frequency and importance. We analyzed data from 2219 children hospitalized with CAP and compared demographic and clinical characteristics and outcomes between groups with viruses alone, bacteria alone, or coinfections. We also assessed the frequency of selected pairings of codetected pathogens and their clinical characteristics. A total of 576 children (26%) had a coinfection. Children with only virus detected were younger, more likely to be black, and more likely to have comorbidities such as asthma, compared with children infected with typical bacteria alone. Children with virus-bacterium coinfections had a higher frequency of leukocytosis, consolidation on chest radiography, parapneumonic effusions, intensive care unit admission, and need for mechanical ventilation and an increased length of stay, compared with children infected with viruses alone. Virus-virus coinfections were generally comparable to single-virus infections, with the exception of the need for oxygen supplementation, which was higher during the first 24 hours of hospitalization in some virus-virus pairings. Coinfections occurred in 26% of children hospitalized for CAP. Children with typical bacterial infections, alone or complicated by a viral infection, have worse outcomes than children infected with a virus alone.

Highly Pathogenic Avian Influenza H5N1 in Chickens in Upper Egypt

One-year surveillance of HPAI (H5N1) virus infection in different chicken flocks (141 flock) from different Governorates in Upper Egypt was carried out, during the period from January 2015 to January 2016. The detection rate of highly pathogenic avian influenza (HPAI) H5N1 virus was 21.3% (30/141) which was highest during the winter season compared with the other seasons. The investigated flocks suffered from respiratory and nervous signs and cyanosis of the comb and wattles was observed in some birds as well as subcutaneous hemorrhages in shanks. The thirty positive H5N1 samples were tested for the existence of other respiratory viruses. The results were as follows: single H5N1 virus infection was only detected in 5 flocks (16.6%). The mixed H5N1 with H9N2 in 2 flocks (6.6%); H5N1with NDV in 12 farms (40%); H5N1 with IBV in 7 farms (23.3%) while H5N1, H9N2 and NDV were detected together in 4 flocks (13.3 %). The sequence analysis of the HA gene from five selected H5N1 isolates revealed that these strains were clustered with Egyptian classical H5N1 viruses (sub-clade 2.2.1.2) of the Eurasian origin. It is concluded that, the five H5N1 subtype isolates of HPAI are clustered with classical H5N1 viruses to subclade 2.2.1.2 of Eurasian origin. Therefore, vaccination of the backyard chicken as well as chicken farms with suitable homologues vaccine to eliminate HPAI virus from Egypt is recommended.

Comparison of Viral Loads in Patients with Co-infections vs. Single-virus Infections

Abstract Background Molecular testing for respiratory viruses in clinical practice is common, often with multiple viruses detected. Viral load has been correlated with illness severity, but correlation of co-detection of viruses and viral load is less clear. We sought to compare cycle threshold (Ct) values, a marker inversely related to viral load, between single vs. co-detection of common respiratory viruses. Methods Children <18 years with respiratory symptoms and/or fever who presented to the ED or were admitted were enrolled. Nasal/throat specimens were obtained and combined. Singleplex qRT-PCR was used to test for 11 respiratory viruses. Clinical and demographic information were collected. Results From 11/15/15-7/15/16, 1255 children were enrolled, with median age of 26.5 months, 53.4% male, 54.3% White, 38.7% Black, 6.4% other, and 23.5% Hispanic. The median days of illness were 3 days. Of the total cohort, 904 (72%) tested positive for at least one viral pathogen. Table 1compares Ct values of single vs. co-detection for each individual virus. Conclusion Single detection with RSV, HRV, AdV, and PIV had lower Ct values, indicating higher viral loads, compared with co-detection with other viruses. Additional research is needed to understand the reason for lower viral loads for co-detection vs. single detection in select respiratory viruses. Disclosures W. Schaffner, Pfizer: Scientific Advisor, Consulting fee. Merck: Scientific Advisor, Consulting fee. Novavax: Consultant, Consulting fee. Dynavax: Consultant, Consulting fee. Sanofi-pasteur: Consultant, Consulting fee. GSK: Consultant, Consulting fee. Seqirus: Consultant, Consulting fee. N. B. Halasa, sanofi pasteur: Research Contractor, Research support. Astra Zeneca: Research Contractor, Grant recipient.

Study of viruses co-infecting white clover (Trifolium repens) in China

Globally, white clover (Trifolium repens L.) is commonly infected by plant viruses. It is grown at gardens, roadsides, and public areas as ornamental plants in northern China. Some leaves present disease symptoms that are similar to those of virus infection. However, to our knowledge, no records are available from China regarding white clover (Trifolium repens L.) virus co-infection. To determine the viral species that infect white clover in China, plant samples with virus disease symptoms were collected and virion morphology and ultrastructure morphology of co-infected plants were observed by electron microscopy; viruses were detected by enzyme linked immunosorbent assay (ELISA) and reverse transcription PCR (RT-PCR). Virus co-infection was studied by double antibody sandwich enzyme linked immunosorbent assay (DAS-ELISA) and real-time fluorescence quantitative PCR (RT-qPCR) after rub-inoculation of virus-free white clover planted in a growth chamber (25°C) with a photoperiod of 16 h, using single or several purified virions. Results showed that there were six types of symptoms, including those of shrinking mosaic, shrinking and macular mosaic, severe mottle mosaic, yellow macular mosaic, shrinkage chlorisis, and ring plaque and ring stria. The incidence rates for each symptom were 20.93, 1.48, 16.85, 59.07, 1.30, and 0.37%, respectively, based on the field investigation. Two types of viral pathogens were identified as Alfalfa mosaic virus (AMV) and White clover mosaic virus (WCMV). In mesophyll cells, virus particles with bacilliform virions formed aggregates and linear virions were bundle shaped. The detection rate of AMV was 100% in white clover samples by DAS-ELISA and RT-PCR detection, whereas that of WCMV was 83.33%. The co-infection rate was 83.33%. The relative contents of AMV and WCMV were significantly increased by 5.897- and 3.515-fold upon co-infection, when compared to that with single virus infection. We observed larger starch particles and fewer or collapsed chloroplast grana in co-infected plants; in addition, vacuoles were twisted and smaller, compared to those of healthy plants. To our knowledge, this is the first report of co-infection by AMV and WCMV in white clover, which has caused severe mosaicism and ultrastructure lesions in co-infected plants in China.

Detection and clinical observation of viral infection in patients with acute exacerbation of chronic obstructive pulmonary disease

Objective To analyze the viral infection in patients with acute exacerbation of chronic obstructive pulmonary disease(COPD) and its clinical significance. Methods 350 patients with acute exacerbation of COPD were collected.The viral infection and clinical manifestations, pulmonary function and imaging features were detected and analyzed. Results A total of 104 patients with viral infection, the proportion was 29.7%.Single virus infection in 74 cases(71.2%), the highest proportion was FluB(19.2%) in pathogen type, followed by FluA(15.4%). Multiple virus infection in 30 cases(28.8%), the highest proportion was RSV+ FluB(11.5%). The virus infection in patients with sore throat(20.2% vs.6.9%), lung function grade(32.7% vs.20.3%), presence of pulmonary inflammatory lesions(57.7% vs.40.7) and the death rate(12.5% vs.0.8%) were significantly higher than those of the combined group of virus infection, the proportion of lung function was significantly lower than patients without viral infection, the differences were statistically significant(χ2=6.546, 5.477, 4.987, 4.124, 3.997, all P<0.05). The proportion of respiratory failure in patients with acute COPD infection was 86.5%, which was higher than 62.6% of patients without viral infection, the difference was statistically significant(χ2=19.837, P<0.05). Conclusion Acute exacerbation of COPD has a high proportion of virus infection, and the prognosis of patients is poor. Key words: Pulmonary disease, chronic obstructive; Viruses; Respiratory function tests; Infection

Analysis of quasispecies variation in single and mixed viral infection.

Population diversity was examined in individual and natural mixed infections of Cowpea chlorotic mottle virus (CCMV) and Cucumber mosaic virus (CMV) isolates in two systemic hosts, cowpea and Nicotiana benthamiana. Isolates of CCMV and CMV obtained from a cowpea field in Arkansas were separated biologically in cowpea and tobacco plants, respectively. After separation, individual and mixed cultures of both viruses were serially passaged ten times by mechanical inoculation in cowpea and N. benthamiana. High-fidelity reverse transcriptase-polymerase chain reaction (HiFi RT-PCR) of RNA 3, followed by cDNA cloning and sequence analysis was used to assess the quasispecies cloud size of CCMV and CMV populations in passages zero and ten of each host species. The levels of population variation were generally higher in individual infections of CCMV-Car1 and-Car2 isolates, and the CMV-Car2 isolate compared with mixed infections, in both host species, although the significance of the differences varied depending on how mutations were counted. There were no significant differences in the levels of population variation in individual and mixed infections of the CMV-Car1 isolate. Partially fixed mutations were observed in both individual and mixed infections of the CCMV-Car2 isolate in N. benthamiana and CMV-Car1 and-Car2 isolates in both cowpea and N. benthamiana.

Serological data of bovine herpes virus type-1 and bovine viral diarrhea virus infections in various ruminants in small-scale farms in the Central and Eastern Black Sea Region, Turkey

Bovine viral diarrhea virus (BVDV) and Bovine herpes virus type-1 (BHV-1) are economically important pathogens leading to critical health problems for widespread ruminant populations worldwide. This study was conducted in order to update the seroprevalence of both viruses in non-vaccinated ruminant breeding enterprises in the Black Sea Region of Turkey. Blood samples (n=1.025) were collected from 192 small-scale farms and were screened using a virus neutralization test. Overall percentages of BVDV and BHV-1 were 19.90 % and 13.56 %, respectively. All goat and cattle enterprises were seropositive for BVDV. Single and dual virus infections rates were 24.87 % and 5.26 % respectively. The Black Sea Region of Turkey has a great number of small-sized ruminant farms and the results confirmed that BVDV and BHV-1 viruses were still in circulation and a wide range of large and small ruminants were exposed to both viruses.

Short-term relevance of lower respiratory viral coinfection in inpatients under 2 years of age.

IntroductionAdvances in molecular diagnosis have made it possible to detect previously unknown viral agents as causative agents of lower respiratory tract infections (LRTI). The frequency and relevance of viral coinfections is still debatable.ObjectiveCompare clinical presentation and severity between single virus infection and viral coinfection in children admitted for LRTI.MethodsA 3-year period observational study (2012–2015) included children younger than two years admitted for LRTI. Viral identification was performed using PCR technique for 16 viruses. Clinical data and use of health resources was gathered during hospital stay using a standard collection form and we compared single virus infection and viral coinfections.ResultsThe study included 524 samples (451 patients); 448 (85.5%) had at least one virus identified. Viral coinfections were found in 159 (35.5%). RSV and HRV were the most commonly identified virus; bronchiolitis and pneumonia the most frequent diagnosis. Patients with viral coinfections were older, attended day-care centers, had previous recurrent wheezing more frequently and were more symptomatic at admission. These patients did not have more complementary exams performed but were prescribed medications more often. Viral coinfection group did not show longer length of hospital stay and oxygen need, more need for ICU nor ventilatory support.DiscussionOur study showed a significant proportion of viral coinfections in young infants admitted with LRTI and confirmed previous data showing that prescription was more frequent in inpatients with viral coinfections, without an association with worst clinical outcome.

Sour and duke cherry viruses in South-West Europe

This study investigated the phytosanitary status of sour and duke cherry genetic resources in the Iberian Peninsula, and the incidence and leaf symptoms induced by the Prunus necrotic ringspot virus (PNRSV), Prune dwarf virus (PDV) and Apple chlorotic leaf spot virus (ACLSV). Young leaf samples were taken from 204 sour and duke cherry trees belonging to ten cultivars, and were assayed by DAS-ELISA. Samples positive for any of the three viruses were also tested by RT-PCR. To associate the leaf symptoms with virus presence, 50 mature leaves from each infected tree were visually inspected during the summer. The ELISA and RT-PCR results indicated that 63% of the cherry trees were infected by at least one of these viruses. PNRSV occurred in all cultivars sampled and presented the highest infection rate (46%), followed by PDV (31%) and ACLSV (6%). Many trees, (60 to 100%), were asymptomatic while harbouring single and mixed virus infections. The leaf symptoms associated with the viruses included chlorotic and dark brown necrotic ringspots on secondary veins and interveinal regions, for PNRSV, generalized chlorosis around the midveins, for PDV, chlorotic and reddish necrotic ringspots, for ACLSV, and generalized interveinal chlorosis, for mixed PNRSV and PDVinfections.

Frequency of respiratory viruses among patients admitted to 26 Intensive Care Units in seven consecutive winter-spring seasons (2009–2016) in Northern Italy

BackgroundThe role of respiratory viruses in the etiology of community-acquired pneumonia (CAP) is still debated. The advent of molecular assays has improved the identification of viruses in patients with CAP and according to published studies, viruses account for 11-55% of adult CAP cases. Objectives and study designIn the present study, the frequency of respiratory viruses was evaluated in respiratory samples collected from 414 patients with CAP admitted to 26 ICUs in the Lombardy Region (10 million inhabitants) during seven winter-spring seasons (2009–2016). ResultsIn 226 (54.6%) patients one or more respiratory viruses were identified, while 188 (45.4%) patients were negative. A single virus infection was observed in 214/226 (94.7%) patients; while, in 12/226 (5.3%) at least two respiratory viruses were detected. Influenza A was the most common virus in 140/226 patients (61.9%) followed by rhinoviruses (33/226, 14.6%), respiratory syncytial virus (13/226, 5.8%), influenza B virus (9/226, 4.0%), human coronaviruses (9/226, 4.0%), cytomegalovirus (9/226, 4.0%) and human metapneumovirus (1/226, 0.4%). ConclusionsViral infections are present in a consistent proportion of patients admitted to the ICU for CAP. Influenza A and rhinovirus accounted for three-quarters of all CAP in ICU patients. The use of lower respiratory instead of upper respiratory samples might be useful in the diagnosis of viral CAP.

Rates of single and multiple virus infection in the honey bee, Apis mellifera

Colony collapse disorder has increased interest in the role of viruses in honey bee health. In this study, we determine if management practices affect the rates of infection for six common viruses by comparing the rates of infection between migratory, queen breeder, and hobbyist beekeepers. The study found that migratory beekeepers had higher rates of infection for Israeli acute paralysis virus and Kashmir bee virus. Migratory beekeepers also had higher rates of infection by more than one virus within a single colony. These results highlight the importance of management practices, perhaps including housing bees at high density, for the prevention of viral infection.

Pitfalls in interpretation of CT-values of RT-PCR in children with acute respiratory tract infections

BackgroundThe relation between viral load and disease severity in childhood acute respiratory tract infections (ARI) is not fully understood. ObjectivesTo assess the clinical relevance of the relation between viral load, determined by cycle threshold (CT) value of real-time reverse transcription-polymerase chain reaction assays and disease severity in children with single- and multiple viral ARI. Study design582 children with ARI were prospectively followed and tested for 15 viruses. Correlations were calculated between CT values and clinical parameters. ResultsIn single viral ARI, statistically significant correlations were found between viral loads of Respiratory Syncytial Virus (RSV) and hospitalization and between viral loads of Human Coronavirus (HCoV) and a disease severity score. In multiple-viral ARI, statistically significant correlations between viral load and clinical parameters were found. In RSV-Rhinovirus (RV) multiple infections, a low viral load of RV was correlated with a high length of hospital stay and a high duration of extra oxygen use. The mean CT value for RV, HCoV and Parainfluenza virus was significantly lower in single- versus multiple infections. ConclusionAlthough correlations between CT values and clinical parameters in patients with single and multiple viral infection were found, the clinical importance of these findings is limited because individual differences in host-, viral and laboratory factors complicate the interpretation of statistically significant findings. In multiple infections, viral load cannot be used to differentiate between disease causing virus and innocent bystanders.

English

Common impromptu observations between 2010 and 2012 of apparent virus-like disease symptoms in watermelons and pumpkins in Uganda prompted this study. However, there was no recorded evidence of virus infection in these crops anywhere in Uganda or eastern Africa as a region. Thus, 374 and 522 watermelon and pumpkin plants, respectively, growing in 13 fields were surveyed to record virus-like disease symptoms in Uganda’s four districts of Mbale and Kamuli (eastern region), Mpigi and Masaka (central region) during August to November 2013, and January to March 2014. Leaf samples were also collected and tested for four viruses known to commonly infect watermelons and pumpkins worldwide. Symptom severity was assessed using a scale of 0 to 5, while virus incidence was determined by serological methods. The four viruses tested were Cucumber mosaic virus (CMV), Watermelon mosaic virus (WMV), Zucchini yellow mosaic virus (ZYMV) and Cucurbit aphid borne-yellows virus (CABYV). In both crops, there was a higher incidence of virus-like diseases in central than in eastern region (P = 0.000). All the four viruses were detected with CMV as the most common, followed by WMV, ZYMV, and CABYV. Differences in virus incidences between the districts were not always significant. Single CMV, dual CMV+WMV and triple CMV+WMV+ZYMV were the most common single, and multiple infections in both crops. Watermelons contained more single virus infections than mixed infections (P < 0.001), but this difference was not significant in pumpkins (P = 0.468). In all, single virus infections were significantly higher in watermelons than pumpkins (P < 0.001). This is the first study to report incidence of viruses and virus-like diseases in watermelons and pumpkins in Uganda, and in eastern Africa as a region. The importance of these results with respect to crop production and next steps in virus disease management are discussed. Key words: Cucurbits, DAS-ELISA, multiple virus infection, TAS-ELISA, virus incidence, Uganda.