ABSTRACT
BACKGROUND: Drug-resistant tuberculosis, especially multidrug-resistant tuberculosis (MDR-TB), is a major public health problem. Effective management of MDR-TB relies on accurate and rapid diagnosis. In this study, we assessed the diagnostic accuracy of the Genotype MTBDRplus assay in diagnosing MDR-TB in Cameroon, and then discuss on its utility within the diagnostic algorithm for MDR-TB. METHODS: In this cross-sectional study, 225 isolates of Mycobacterium tuberculosis cultured from sputum samples collected from new and previously treated pulmonary tuberculosis patients in Cameroon were used to determine the accuracy of the Genotype MTBDRplus assay. We compared the results of the Genotype MTBDRplus assay with those from the automated liquid culture BACTEC MGIT 960 SIRE system for sensitivity, specificity, and degree of agreement. The pattern of mutations associated with resistance to RIF and INH were also analyzed. RESULTS: The Genotype MTBDRplus assay correctly identified Rifampicin (RIF) resistance in 48/49 isolates (sensitivity, 98% [CI, 89%-100%]), Isoniazid (INH) resistance in 55/60 isolates (sensitivity 92% [CI, 82%-96%]), and MDR-TB in 46/49 (sensitivity, 94% [CI, 83%-98%]). The specificity for the detection of RIF-resistant and MDR-TB cases was 100% (CI, 98%-100%), while that of INH resistance was 99% (CI, 97%-100%). The agreement between the two tests for the detection of MDR-TB was very good (Kappa = 0.96 [CI, 0.92-1.00]). Among the 3 missed MDR-TB cases, the Genotype MTBDRplus assay classified two samples as RIF-monoresistant and one as INH monoresistant. The most frequent mutations detected by the Genotype MTBDRplus assay was the rpoB S531 L MUT3 41/49 (84%) in RIF-resistant isolates, and the KatG S315 T1 (MUT1) 35/55 (64%) and inhA C15T (MUT1) 20/55 (36%) mutations in INH-resistant isolates. CONCLUSION: The Genotype MTBDRplus assay had good accuracy and could be used for the diagnosis of MDR-TB in Cameroon. For routine MDR-TB diagnosis, this assay could be used for Mycobacterium tuberculosis cultures containing contaminants, to complement culture-based drug susceptibility testing or to determine drug resistant mutations.
Subject(s)
Molecular Diagnostic Techniques/methods , Mycobacterium tuberculosis/drug effects , Mycobacterium tuberculosis/genetics , Tuberculosis, Multidrug-Resistant/diagnosis , Tuberculosis, Pulmonary/microbiology , Adult , Antitubercular Agents/therapeutic use , Bacterial Proteins/genetics , Cameroon , Cross-Sectional Studies , Female , Genotype , Genotyping Techniques/methods , Humans , Isoniazid/pharmacology , Male , Microbial Sensitivity Tests/methods , Middle Aged , Mutation , Mutation Rate , Mycobacterium tuberculosis/isolation & purification , Oxidoreductases/genetics , Rifampin/pharmacology , Sensitivity and Specificity , Tuberculosis, Multidrug-Resistant/drug therapy , Tuberculosis, Multidrug-Resistant/microbiology , Tuberculosis, Pulmonary/diagnosis , Tuberculosis, Pulmonary/drug therapyABSTRACT
BACKGROUND: The host response to infection by Plasmodium falciparum, the parasite most often responsible for severe malaria, ranges from asymptomatic parasitaemia to death. The clinical trajectory of malaria is influenced by host genetics and parasite load, but the factors determining why some infections produce uncomplicated malaria and some proceed to severe disease remain incompletely understood. METHODS: To identify molecular markers of severe falciparum malaria, human gene expression patterns were compared between children aged 6 months to 5 years with severe and uncomplicated malaria who were enrolled in a case-control study in Bandiagara, Mali. Microarrays were used to obtain expression data on severe cases and uncomplicated controls at the time of acute disease presentation (five uncomplicated and five severe), 1 week after presentation (three uncomplicated and three severe) and treatment initiation, and in the subsequent dry season (late convalescence, four uncomplicated and four severe). This is a pilot study for the first use of microarray technology in Mali. RESULTS: Complement and toll-like receptor (TLR) pathways were differentially expressed, with severe cases showing higher expression of the C1q, TLR2, TLR4, TLR8, and CR1 genes. Other genes previously associated with malaria pathogenesis, GZMB, FOS and HSPA6, were also higher among severe cases. TLR2, TLR4, TLR8, CR1, GZMB, FOS, and HSPA6 genes were expressed at lower levels in severe cases at late convalescence. CONCLUSIONS: Overexpression of genes previously associated with uncomplicated malaria was associated with severe disease. Low baseline expression of these genes may represent candidate markers for severe malaria. Despite the small sample size, results of this pilot study offer promising targets for follow-up analyses.
Subject(s)
Complement System Proteins/genetics , Malaria, Falciparum/epidemiology , Malaria, Falciparum/genetics , Toll-Like Receptors/genetics , Biomarkers/metabolism , Case-Control Studies , Child, Preschool , Cluster Analysis , Complement System Proteins/metabolism , Female , Gene Expression Profiling , Humans , Infant , Malaria, Falciparum/metabolism , Malaria, Falciparum/physiopathology , Male , Mali , Molecular Epidemiology , Oligonucleotide Array Sequence Analysis , Pilot Projects , Plasmodium falciparum , Toll-Like Receptors/metabolismABSTRACT
BACKGROUND: Hepatitis B (HB) infection is common in Mali. However, there is little information on molecular and biochemical characteristics of HB carriers. METHODS: A group of 1466 adult volunteers was recruited in the district of Bamako. Confirmed HB carriers were tested for HB viral load by quantitative PCR and HBV was genotyped by sequencing of HBS. Fibrosis and hepatitis activity were measured using the Fibrotest-Actitest. A mutation of TP53 at codon 249 (R249S), specific for exposure to aflatoxin, was detected in cell-free DNA extracted from plasma. RESULTS: Overall, 276 subjects were HBsAg-positive (18.8%). Among 152 subjects tested for HBV load, 49 (32.2%) had over 10(4) copies/mL and 16 (10.5%) had levels below the limit of detection. The E genotype was found in 91.1% of carriers. Fibrotest scores ≥ F2 were observed in 52 subjects (35.4%). Actitest scores ≥ A2 were detected in 15 subjects (10.2%) and were correlated with Fibrotest scores (p = 0.0006). Among 105 subjects tested, 60% had detectable levels of R249S copies (>40 copies/mL plasma). CONCLUSION: Chronic HB carriage in adults in Bamako district is well over epidemic threshold. About 1/3 of carriers have moderate to severe liver fibrosis and 60% have detectable aflatoxin-related TP53 R249S mutation. These results support introduction of anti-HB therapies to reduce the progression towards severe liver disease.
Subject(s)
Carrier State/virology , Hepatitis B virus/genetics , Hepatitis B virus/isolation & purification , Hepatitis B/complications , Hepatitis B/virology , Liver Cirrhosis/complications , Liver Cirrhosis/virology , Adolescent , Adult , Aflatoxins/toxicity , Aged , DNA Mutational Analysis , Female , Genes, p53/genetics , Genotype , Hepatitis B/epidemiology , Hepatitis B/pathology , Hepatitis B Surface Antigens/blood , Humans , Liver Cirrhosis/epidemiology , Liver Cirrhosis/pathology , Male , Mali/epidemiology , Middle Aged , Mutation/genetics , Viral Load , Young AdultABSTRACT
Antimicrobial drug resistance is usually not monitored in under-resourced countries because they lack surveillance networks, laboratory capacity, and appropriate diagnostics. This accelerating problem accounts for substantial number of excess deaths, especially among infants. Infections particularly affected by antimicrobial drug resistance include tuberculosis, malaria, severe acute respiratory infections, and sepsis caused by gram-negative bacteria. Nonetheless, mapping antimicrobial drug resistance is feasible in under-resourced countries, and lessons can be learned from previous successful efforts. Specimen shipping conditions, data standardization, absence of contamination, and adequate diagnostics must be ensured. As a first step toward solving this problem, we propose that a road map be created at the international level to strengthen antimicrobial resistance surveillance in under-resourced countries. This effort should include a research agenda; a map of existing networks and recommendations to unite them; and a communication plan for national, regional, and international organizations and funding agencies.
Subject(s)
Developing Countries , Drug Resistance, Microbial , Population Surveillance , Communicable Diseases/diagnosis , Communicable Diseases/epidemiology , Communicable Diseases/microbiology , Communicable Diseases/parasitology , Global Health , HumansABSTRACT
UNLABELLED: Anti-hepatitis B virus (HBV) nucleos(t)ides analogs (NA) exert selective pressures on polymerase (pol) and surface (S) genes, inducing treatment resistance and increasing the risk of vaccine escape mutants. The rate of emergence for these mutations is largely unknown in patients coinfected with human immunodeficiency virus (HIV) and HBV undergoing dual-active therapy. In a 3-year, repeat-sampling, prospective cohort study, HBV viral genome sequences of 171 HIV-HBV coinfected patients, presenting with HBV viremia for at least one visit, were analyzed every 12 months via DNA chip. Logistic and Cox proportional hazard models were used to determine risk factors specifically for S gene mutations at baseline and during follow-up, respectively. HBV-DNA levels >190 IU/mL substantially decreased from 91.8% at inclusion to 40.3% at month 36 (P < 0.001), while lamivudine (LAM) or emtricitabine (FTC) use remained steady (71.9%) and tenofovir (TDF) use expanded (month 0, 17.5%; month 36, 66.7%; P < 0.001). The largest increase of any mutation class was observed in l-nucleoside-associated pol gene/antiviral-associated S gene mutations (cumulative incidence at the end of follow-up, 17.5%) followed by alkyl phosphonate-associated pol-gene (7.4%), immune-associated S gene (specifically any amino acid change at positions s120/s145, 6.4%), and d-cyclopentane-associated pol-gene mutations (2.4%). Incidence of l-nucleoside-associated pol-gene/antiviral-associated S gene mutations was significantly associated with concomitant LAM therapy (adjusted hazard ratio [HR], 4.61; 95% confidence interval [CI], 1.36-15.56), but inversely associated with TDF use (adjusted HR/month, 0.94; 95% CI,0.89-0.98). Cumulative duration of TDF was significantly associated with a reduction in the occurrence of immune-associated S gene mutations (HR/month, 0.88; 95% CI, 0.79-0.98). No major liver-related complications (e.g., fulminant hepatitis, decompensated liver, and hepatocellular carcinoma) were observed in patients with incident mutations. CONCLUSION: Vaccine escape mutants selected by NA exposure were frequent and steadily increasing during follow-up. Although the high antiviral potency of TDF can mitigate incident mutations, other antiviral options are limited in this respect. The public health implications of their transmission need to be addressed.
Subject(s)
Antiviral Agents/pharmacology , HIV Infections/genetics , Hepatitis B Vaccines/pharmacology , Hepatitis B virus/genetics , Hepatitis B/genetics , Mutation/drug effects , Mutation/genetics , Adult , Cohort Studies , Comorbidity , DNA, Viral/genetics , Female , Follow-Up Studies , Genes, pol/genetics , HIV Infections/epidemiology , Hepatitis B/epidemiology , Hepatitis B virus/drug effects , Humans , Incidence , Male , Middle Aged , Prevalence , Prospective Studies , Retrospective Studies , Risk FactorsABSTRACT
BACKGROUND: Data on the etiologies of pneumonia among children are inadequate, especially in developing countries. The principal objective is to undertake a multicenter incident case-control study of <5-year-old children hospitalized with pneumonia in developing and emerging countries, aiming to identify the causative agents involved in pneumonia while assessing individual and microbial factors associated with the risk of severe pneumonia. METHODS/DESIGN: A multicenter case-control study, based on the GABRIEL network, is ongoing. Ten study sites are located in 9 countries over 3 continents: Brazil, Cambodia, China, Haiti, India, Madagascar, Mali, Mongolia, and Paraguay. At least 1,000 incident cases and 1,000 controls will be enrolled and matched for age and date. Cases are hospitalized children <5 years with radiologically confirmed pneumonia, and the controls are children without any features suggestive of pneumonia. Respiratory specimens are collected from all enrolled subjects to identify 19 viruses and 5 bacteria. Whole blood from pneumonia cases is being tested for 3 major bacteria. S. pneumoniae-positive specimens are serotyped. Urine samples from cases only are tested for detection of antimicrobial activity. The association between procalcitonin, C-reactive protein and pathogens is being evaluated. A discovery platform will enable pathogen identification in undiagnosed samples. DISCUSSION: This multicenter study will provide descriptive results for better understanding of pathogens responsible for pneumonia among children in developing countries. The identification of determinants related to microorganisms associated with pneumonia and its severity should facilitate treatment and prevention.
Subject(s)
Clinical Protocols , Developing Countries , Pneumonia/etiology , Anti-Bacterial Agents/urine , Bacteria/isolation & purification , Brazil , C-Reactive Protein/metabolism , Calcitonin/blood , Calcitonin Gene-Related Peptide , Cambodia , Case-Control Studies , Child, Preschool , China , Female , Haiti , Humans , India , Infant , Madagascar , Male , Mali , Mongolia , Paraguay , Pleural Effusion/microbiology , Pneumonia/blood , Pneumonia/metabolism , Pneumonia/urine , Protein Precursors/blood , Viruses/isolation & purificationABSTRACT
An unexplained increase in the incidence of parapneumonic empyema (PPE) in pneumonia cases has been reported in recent years. The present study investigated the genetic and biological specifications of new isolates of torque teno mini virus (TTMV) detected in pleural effusion samples from children hospitalised for severe pneumonia with PPE. A pathogen discovery protocol was applied in undiagnosed pleural effusion samples and led to the identification of three new isolates of TTMV (TTMV-LY). Isolated TTMV-LY genomes were transfected into A549 and human embryonic kidney 293T cells and viral replication was assessed by quantitative real-time PCR and full-length genome amplification. A549 cells were further infected with released TTMV-LY virions and the induced-innate immune response was measured by multiplex immunoassays. Genetic analyses of the three TTMV-LY genomes revealed a classic genomic organisation but a weak identity (<64%) with known sequences. We demonstrated the in vitro replication of TTMV-LY in alveolar epithelial cells and the effective release of infectious viral particles. We also showed a selective production of inflammatory mediators in response to TTMV infection. This study reports the description of replicative TTMV-LY isolated from parapneumonic effusions of children hospitalised with PPE, suggesting a potential role of the virus in the pathogenesis of pneumonia.
Subject(s)
Empyema/virology , Pneumonia, Viral/virology , Torque teno virus/isolation & purification , Adolescent , Base Sequence , Cell Line, Tumor , Chemokines/metabolism , Child , Child, Preschool , Cytokines/metabolism , DNA, Viral/analysis , Female , HEK293 Cells , Humans , Immunoassay , Infant , Male , Molecular Sequence Data , Nucleic Acid Conformation , Open Reading Frames , Phylogeny , Pleural Effusion , Pneumonia, Viral/physiopathology , Prevalence , Prospective StudiesABSTRACT
Community-acquired pneumonia is a major cause of morbidity and mortality in children worldwide. However, few studies have been conducted on the infection of human metapneumovirus (hMPV) associated with pediatric community-acquired pneumonia in China. Nasopharyngeal aspirates were collected between July 2008 and June 2010 from 1,028 children, aged ≤16.5 years, who were diagnosed with community-acquired pneumonia in Beijing, China. Reverse-transcriptase polymerase chain reaction was used to screen the samples for hMPV and common respiratory viruses. hMPV was detected in 6.3% of the patients with community-acquired pneumonia. This detection rate is the third highest for a respiratory virus in children with community-acquired pneumonia, after that of rhinovirus (30.9%) and respiratory syncytial virus (30.7%). The detection rate of hMPV in 2008/2009 (42/540, 7.8%) was significantly higher than in 2009/2010 (23/488, 4.7%; χ(2) = 4.065, P = 0.044). The hMPV subtypes A2, B1, and B2 were found to co-circulate, with A2 being most prevalent. These results indicate that hMPV plays a substantial role in pediatric community-acquired pneumonia in China. Overall, these findings provide a better understanding of the epidemiological and clinical features of hMPV infections.
Subject(s)
Community-Acquired Infections/epidemiology , Metapneumovirus/isolation & purification , Paramyxoviridae Infections/epidemiology , Pneumonia, Viral/epidemiology , Adolescent , Child , Child, Preschool , China/epidemiology , Clinical Laboratory Techniques/methods , Community-Acquired Infections/virology , Female , Genotype , Humans , Infant , Infant, Newborn , Male , Metapneumovirus/classification , Metapneumovirus/genetics , Nasopharynx/virology , Paramyxoviridae Infections/virology , Pneumonia, Viral/virology , Prevalence , Reverse Transcriptase Polymerase Chain Reaction/methodsABSTRACT
Respiratory syncytial virus (RSV) is a leading cause of respiratory tract illnesses worldwide. Although the prevalence and clinical manifestations of the two subtypes, RSV-A and RSV-B, have been studied in some detail in infants and young children, they have not been determined in adults. To evaluate the prevalence of the RSV subtypes and disease severity between RSV-A and RSV-B infections in adults, nasal and throat swabs that were collected from patients ≥15 years old who sought medical care for acute respiratory infections at the Fever Clinic of the Peking Union Medical College Hospital in Beijing, China between May 2005 and April 2010. The samples were tested for RSV infection using PCR and sequencing analysis. RSV was detected in 95 (1%) of the adult patients, of whom 53 (55.8%) were positive for RSV-A and 42 (44.2%) for RSV-B. The incidence of RSV infections increased with age (χ(2) = 37.17, P = 1.66E-07). Demographic data and clinical manifestations of RSV-A were similar to those of RSV-B. Although RSV-A and RSV-B co-circulated during the 2005-2006 and 2008-2009 seasons, RSV-A was predominant in the 2006-2008 seasons, whereas RSV-B was predominant in the 2009-2010 season. Upper respiratory tract infections were diagnosed in most RSV-infected patients (n = 80, 84.2%), and three patients suffered from pulmonary infection. This is the first study to provide data on the prevalence and clinical manifestations of RSV subgroups among Chinese adults with fever and acute illness, over five successive epidemic seasons.
Subject(s)
Respiratory Syncytial Virus Infections/epidemiology , Respiratory Syncytial Virus Infections/pathology , Respiratory Syncytial Virus, Human/classification , Respiratory Tract Infections/epidemiology , Respiratory Tract Infections/pathology , Adolescent , Adult , Age Factors , Aged , Aged, 80 and over , China/epidemiology , DNA, Viral/chemistry , DNA, Viral/genetics , Female , Humans , Incidence , Male , Middle Aged , Nose/virology , Pharynx/virology , Polymerase Chain Reaction , Prevalence , Respiratory Syncytial Virus Infections/virology , Respiratory Syncytial Virus, Human/genetics , Respiratory Syncytial Virus, Human/isolation & purification , Respiratory Tract Infections/virology , Sequence Analysis, DNA , Young AdultABSTRACT
Background: Large-scale population-based seroprevalence studies of SARS-CoV-2 are essential to characterize the cumulative incidence of SARS-CoV-2 infection and to extrapolate the prevalence of presumptive immunity at the population level. Objective. The objective of our survey was to estimate the cumulative population immunity for COVID-19 and to identify individual characteristics associated with positive serostatus. Materials and Methods: This was a clustered cross-sectional study conducted from July 12 to August 20, 2021, in households in the city of Bangui, the capital of the Central African Republic. Information regarding demographic characteristics (age, gender, and place of residence), and comorbidities (chronic diseases) was collected. A venous blood sample was obtained from each participant to determine the level of total anti-SARS-CoV-2 antibodies using a WANTAI SARS-CoV-2 Ab ELISA kit. Results: All up, 799 participants were surveyed. The average age was 27 years, and 45.8% of the respondents were male (sex ratio: 0.8). The overall proportion of respondents with positive serostatus was 74.1%. Participants over 20 years of age were twice as likely to have positive serostatus, with an OR of 2.2 [95% CI: (1.6, 3.1)]. Conclusions: The results of this survey revealed a high cumulative level of immunity in Bangui, thus indicating a significant degree of spread of SARS-CoV-2 in the population. The public health implications of this immunity to SARS-CoV-2 such as the post-vaccination total antibody kinetics remain to be determined.
ABSTRACT
Healthcare workers (HCWs) are at high to very high risk for SARS-CoV-2 infection. The persistence of this pandemic worldwide has instigated the need for an investigation of the level of prevention through immunization and vaccination against SARS-CoV-2 among HCWs. The objective of our study was to evaluate any changes in anti-COVID-19 serological status before and after the vaccination campaign of health personnel in the Central African Republic. We carried out a repeated cross-sectional serological study on HCWs at the university hospital centers of Bangui. Blood samples were collected and tested for anti-SARS-CoV-2 IgM and IgG using the ELISA technique on blood samples. A total of 179 and 141 HCWs were included in the first and second surveys, respectively. Of these staff, 31.8% of HCWs were positive for anti-SARS-CoV-2 IgG in the first survey, whereas 95.7% were positive for anti-SARS-CoV-2 IgG in the second survey. However, the proportion of HCWs positive for SARS-CoV-2 IgM antibodies was low (9.7% in the first survey and 3.6% in the second survey). These findings showed a sharp increase in seroprevalence over a one-year period. This increase is primarily due to the synergistic effect of the infection and the implementation of vaccines against COVID-19. Further studies to assess the persistence of anti-SARS-CoV-2 antibodies are needed.
ABSTRACT
During August 2006-April 2010, in Beijing, China, 2 rare human enterovirus serotypes, coxsackievirus A21 and enterovirus 68, were detected most frequently in human enterovirus-positive adults with acute respiratory tract infections. Thus, during some years, these 2 viruses cause a substantial proportion of enterovirus-associated adult acute respiratory tract infections.
Subject(s)
Coxsackievirus Infections/virology , Enterovirus Infections/virology , Enterovirus/classification , Respiratory Tract Infections/virology , Acute Disease , Adolescent , Adult , Aged , Coxsackievirus Infections/diagnosis , Enterovirus/genetics , Enterovirus/isolation & purification , Enterovirus Infections/diagnosis , Female , Humans , Male , Middle Aged , Molecular Sequence Data , Phylogeny , Respiratory Tract Infections/diagnosis , Viral Structural Proteins/genetics , Young AdultABSTRACT
OBJECTIVE: To determine the prevalence of multidrug-resistant tuberculosis (MDR-TB) among patients with new smear-positive pulmonary TB in Port-au-Prince, Haiti. METHODS: Sputum samples were cultured from 1 006 patients newly diagnosed with TB in 2008. The core region of the rpoB gene that is associated with resistance to rifampin was sequenced. All isolates with rpoB mutations were sent to the New York State reference laboratory for conventional drug susceptibility testing (DST). All isolates were also tested with the GenoType MTBDRplus line-probe assay. RESULTS: Mycobacterium tuberculosis was isolated from 906 patients. Twenty-six (2.9%) of the isolates had missense mutations or deletions in rpoB and were resistant to rifampin by DST. All 26 were also resistant to isoniazid and classified as MDR-TB. Forty-six control isolates without rpoB mutations were found to be rifampin sensitive by DST. The GenoType MTBDRplus line-probe assay correctly identified 26 MDR-TB strains. It misclassified one pansusceptible isolate as rifampin resistant. CONCLUSIONS: This study shows an MDR-TB prevalence of 2.9% in newly diagnosed TB patients in Haiti and suggests that rpoB sequencing and hybridization assays are good screening tools for early detection of MDR-TB.
Subject(s)
Tuberculosis, Multidrug-Resistant/epidemiology , Adult , Antitubercular Agents/pharmacology , Bacterial Proteins/drug effects , Bacterial Proteins/genetics , Cities/epidemiology , Cross-Sectional Studies , DNA-Directed RNA Polymerases , Female , Haiti/epidemiology , Humans , Isoniazid/pharmacology , Male , Mycobacterium tuberculosis/genetics , Prevalence , Rifampin/pharmacology , Tuberculosis, Multidrug-Resistant/drug therapy , Tuberculosis, Multidrug-Resistant/genetics , Young AdultABSTRACT
The use of biomarkers to measure immune responses in serum is crucial for understanding population-level exposure and susceptibility to human pathogens. Advances in sample collection, multiplex testing, and computational modeling are transforming serosurveillance into a powerful tool for public health program design and response to infectious threats. In July 2018, 70 scientists from 16 countries met to perform a landscape analysis of approaches that support an integrated serosurveillance platform, including the consideration of issues for successful implementation. Here, we summarize the group's insights and proposed roadmap for implementation, including objectives, technical requirements, ethical issues, logistical considerations, and monitoring and evaluation.
Subject(s)
Communicable Diseases , Public Health , Biomarkers , HumansABSTRACT
For many encephalitis cases, the cause remains unidentified. After 2 children (from the same family) received a diagnosis of acute necrotizing encephalopathy at Centre Hospitalier Universitaire (Tours, France), we attempted to identify the etiologic agent. Because clinical samples from the 2 patients were negative for all pathogens tested, urine and throat swab specimens were added to epithelial cells, and virus isolates detected were characterized by molecular analysis and electron microscopy. We identified a novel reovirus strain (serotype 2), MRV2Tou05, which seems to be closely related to porcine and human strains. A specific antibody response directed against this new reovirus strain was observed in convalescent-phase serum specimens from the patients, whereas no response was observed in 38 serum specimens from 38 healthy adults. This novel reovirus is a new etiologic agent of encephalitis.
Subject(s)
Encephalitis, Viral/virology , Leukoencephalitis, Acute Hemorrhagic/virology , Orthoreovirus, Mammalian/classification , Orthoreovirus, Mammalian/isolation & purification , Reoviridae Infections/virology , Adult , Animals , Antibodies, Viral/blood , Cell Line , Child , Chlorocebus aethiops , Female , France/epidemiology , Hospitals, University , Humans , Infant , Male , Orthoreovirus, Mammalian/genetics , Orthoreovirus, Mammalian/immunology , Phylogeny , Sequence Analysis, DNA , Serotyping , Vero CellsABSTRACT
Real-time reverse transcriptase PCR (rRT-PCR) assays have greatly contributed to the detection, control, and prevention of the pandemic influenza A/H1N1 2009 virus. To improve the rRT-PCR assays for detection of pandemic influenza A/H1N1 2009 virus, we evaluated the sensitivity, specificity, and performance of 12 rRT-PCR primer-probe sets [SW (a) to SW (l)] using a panel of virus strains and clinical specimens. These primer-probe sets were derived from published work and designed for detecting the hemagglutinin (HA) or the neuraminidase (NA) gene of the pandemic influenza A/H1N1 2009 virus. A primer-probe set, SW (CDC), developed by the Centers for Disease Control and Prevention (U.S. CDC) to target the HA gene of pandemic influenza A/H1N1 2009 virus, was used as a referee method. Our results demonstrated that although all primer-probe sets in this study had as high as 98.4 to 100% in silico coverage, some of the primer-probe sets had better specificity, sensitivity, and amplification efficiency than others. Two primer-probe sets, SW (h) and SW (l), which target the NA gene of pandemic influenza A/H1N1 2009 virus, were highly sensitive (10(4) copies/reaction), had high detection rates (56/60, P = 0.134, and 59/60, P = 1.000), and showed ideal specificity compared with SW (CDC). In addition, a cocktail of primer-probe sets targeted to the HA and NA genes displayed higher detection sensitivity than primer-probe sets targeting HA or NA alone, indicating that for practical applications, a combination of primer-probes targeting HA and NA genes is the best option for the detection of pandemic influenza A/H1N1 2009 virus.
Subject(s)
DNA Primers/genetics , Influenza A Virus, H1N1 Subtype/isolation & purification , Influenza, Human/diagnosis , Influenza, Human/virology , Molecular Diagnostic Techniques/methods , Reverse Transcriptase Polymerase Chain Reaction/methods , Virology/methods , Hemagglutinin Glycoproteins, Influenza Virus/genetics , Humans , Influenza A Virus, H1N1 Subtype/genetics , Neuraminidase/genetics , Sensitivity and Specificity , Viral Proteins/geneticsABSTRACT
Human coronaviruses (HCoVs) are a common etiological agent of acute respiratory tract infections. HCoV infections, especially those caused by the two HCoVs identified most recently, NL63 and HKU-1, have not been characterized fully. To evaluate the prevalence and clinical presentations of HKU1 and NL63 in adults with acute respiratory tract infections, an investigation of HCoV infections in Beijing, China from 2005 to 2009 was performed by using reverse transcriptase PCR assays and sequencing analysis. Among 8,396 respiratory specimens studied, 87 (1%) clinical samples were positive for HCoVs, of which 50 samples (0.6% of the total) were positive for HCoV-OC43, 15 (0.2%) for HCoV-229E, 14 (0.2%) for HCoV-HKU1, and 8 (0.1%) for HCoV-NL63. The prevalence of HCoV infection in adults exhibited distinct seasonal fluctuations during the study period. In addition, patients positive for HCoV-229E infections were more likely to be co-infected with other respiratory viruses. Enterovirus, rhinovirus, and parainfluenza virus type 3 were the most common viruses found in patients with HCoV infections. The demographic and clinical data present in this study of HCoV infections in adults with acute respiratory tract infections should improve our understanding of the pathogenesis of HCoVs.
Subject(s)
Coronavirus Infections/epidemiology , Coronavirus/classification , Respiratory Tract Infections/epidemiology , Adolescent , Adult , Aged , Aged, 80 and over , China/epidemiology , Coronavirus/genetics , Coronavirus Infections/virology , Female , Humans , Male , Middle Aged , Molecular Sequence Data , Phylogeny , Prevalence , Respiratory Tract Infections/virology , Reverse Transcriptase Polymerase Chain Reaction , Seasons , Urban PopulationABSTRACT
BACKGROUND: Human metapneumovirus (hMPV), a recently identified virus, causes acute respiratory tract infections (ARTIs) in infants and children. However, studies on the seroepidemeology of hMPV are very limited in China. To assess the seroprevalence of hMPV infection in China, we tested a total of 1,156 serum specimens for the presence of anti-hMPV IgG antibody in children and adults free of acute respiratory illness in Beijing, China by using hMPV nucleocapsid (N) protein as an antigen. As a control, we used the human serum antibody against the N protein of human respiratory syncytial virus (hRSV), the most important viral agent responsible for ARIs in children. RESULTS: The seropositive rate for hMPV increased steadily with age from 67% at 1-6 mo to 100% at age 20. However, the rate dropped slightly between 6 mo and 1 yr of age. The seropositive rate for hRSV also increased steadily with age from 71% at 1-6 mo to 100% at age 20. In children aged six months to six years, the seropositive rates for the anti-hRSV IgG antibody were significantly higher than those for hMPV. Additionally, IgG antibody titers to hMPV and hRSV were significantly higher in adults than in young children. Consistent with the seropositive rates, the geometric mean titer of anti-hMPV IgG antibody was lower than that of anti-hRSV IgG antibody in children aged six months to six years. CONCLUSIONS: Our results indicate that similar to hRSV, exposure to hMPV is ubiquitous in the Beijing population. However, the seroprevalence of anti-hMPV IgG antibody is lower than that of hRSV in children between six months and six years old, which suggests a different number of repeat infections or a different response to infections.
Subject(s)
Antibodies, Viral/blood , Paramyxoviridae Infections/epidemiology , Respiratory Syncytial Virus Infections/epidemiology , Adolescent , Adult , Age Factors , Aged , Aged, 80 and over , Antigens, Viral , Child , Child, Preschool , China/epidemiology , Female , Humans , Immunoglobulin G/blood , Infant , Male , Metapneumovirus/immunology , Middle Aged , Nucleocapsid Proteins , Respiratory Syncytial Virus, Human/immunology , Seroepidemiologic Studies , Young AdultABSTRACT
To clarify the potential for respiratory transmission of Saffold cardiovirus (SAFV) and characterize the pathogen, we analyzed respiratory specimens from 1,558 pediatric patients in Beijing. We detected SAFV in 7 (0.5%) patients and identified lineages 1-3. However, because 3 patients had co-infections, we could not definitively say SAFV caused disease.