Influenza Outbreaks during World Youth Day 2008 Mass Gathering

Novel viruses were introduced and seasonal viruses were amplified

Rapid semi-automated quantitative multiplex tandem PCR (MT-PCR) assays for the differential diagnosis of influenza-like illness

<p>Abstract</p> <p>Background</p> <p>Influenza A, including avian influenza, is a major public health threat in developed and developing countries. Rapid and accurate detection is a key component of strategies to contain spread of infection, and the efficient diagnosis of influenza-like-illness is essential to protect health infrastructure in the event of a major influenza outbreak.</p> <p>Methods</p> <p>We developed a multiplexed PCR (MT-PCR) assay for the simultaneous diagnosis of respiratory viruses causing influenza-like illness, including the specific recognition of influenza A haemagglutinin subtypes H1, H3, and H5. We tested several hundred clinical specimens in two diagnostic reference laboratories and compared the results with standard techniques.</p> <p>Results</p> <p>The sensitivity and specificity of these assays was higher than individual assays based on direct antigen detection and standard PCR against a range of control templates and in several hundred clinical specimens. The MT-PCR assays provided differential diagnoses as well as potentially useful quantitation of virus in clinical samples.</p> <p>Conclusions</p> <p>MT-PCR is a potentially powerful tool for the differential diagnosis of influenza-like illness in the clinical diagnostic laboratory.</p

Influenza Outbreak during Sydney World Youth Day 2008: The Utility of Laboratory Testing and Case Definitions on Mass Gathering Outbreak Containment

BACKGROUND:Influenza causes annual epidemics and often results in extensive outbreaks in closed communities. To minimize transmission, a range of interventions have been suggested. For these to be effective, an accurate and timely diagnosis of influenza is required. This is confirmed by a positive laboratory test result in an individual whose symptoms are consistent with a predefined clinical case definition. However, the utility of these clinical case definitions and laboratory testing in mass gathering outbreaks remains unknown. METHODS AND RESULTS:An influenza outbreak was identified during World Youth Day 2008 in Sydney. From the data collected on pilgrims presenting to a single clinic, a Markov model was developed and validated against the actual epidemic curve. Simulations were performed to examine the utility of different clinical case definitions and laboratory testing strategies for containment of influenza outbreaks. Clinical case definitions were found to have the greatest impact on averting further cases with no added benefit when combined with any laboratory test. Although nucleic acid testing (NAT) demonstrated higher utility than indirect immunofluorescence antigen or on-site point-of-care testing, this effect was lost when laboratory NAT turnaround times was included. The main benefit of laboratory confirmation was limited to identification of true influenza cases amenable to interventions such as antiviral therapy. CONCLUSIONS:Continuous re-evaluation of case definitions and laboratory testing strategies are essential for effective management of influenza outbreaks during mass gatherings

Molecular Identification and Analysis of Nonserotypeable Human Enteroviruses▿ †

Conventional approaches to characterizing human enteroviruses (HEVs) are based on viral isolation and neutralization. Molecular typing methods depend largely on reverse transcription-PCR (RT-PCR) and nucleotide sequencing of the entire or partial VP1 gene. A modified RT-PCR-based reverse line blot (RLB) hybridization assay was developed as a rapid and efficient way to characterize common and nonserotypeable (by neutralization) HEVs. Twenty HEV serotypes accounted for 87.1% of all HEVs isolated at a reference laboratory from 1979 to 2007; these common serotypes were identified using one sense and three antisense primers and a set of 80 serotype-specific probes in VP1 (F. Zhou et al., J. Clin. Microbiol. 47:2737-2743, 2009). In this study, one HEV-specific primer pair, two probes in the 5′ untranslated region (UTR), and a new set of 80 serotype-specific probes in VP1 were designed. First, we successfully applied the modified RT-PCR-RLB (using two HEV-specific probes and two sets of serotype-specific probes) to synchronously detect the 5′ UTR and VP1 regions of 131/132 isolates previously studied (F. Zhou et al., J. Clin. Microbiol. 47:2737-2743, 2009). Then, this method was used to identify 73/92 nonserotypeable HEV isolates; 19 nonserotypeable isolates were hybridized only with HEV-specific probes. The VP1 region of 92 nonserotypeable HEV isolates was sequenced; 73 sequences corresponded with one or both RLB results and 19 (not belonging to the 20 most common genotypes) were identified only by sequencing. Two sets of serotype-specific probes can capture the majority of strains belonging to the 20 most common serotypes/genotypes simultaneously or complementarily. Synchronous detection of the 5′ UTR and VP1 region by RT-PCR-RLB will facilitate the identification of HEVs, especially nonserotypeable isolates

Outbreak of human metapneumovirus inflection in a residential aged care facility

Summer outbreaks of respiratory illness in residential aged care facilities are uncommonly reported in New South Wales. A respiratory illness outbreak in an aged care facility during January 2008 prompted a response to contain the outbreak by implementing infection control measures, including cohorting of symptomatic residents, cohorting nursing care, closure to new admissions and the use of personal protective equipment by staff. In addition, respiratory tract specimens were collected to determine the causative agent. Human metapneumovirus (hMPV) was detected by polymerase chain reaction assay in 3 specimens with no other respiratory pathogens found. This is the 1st reported outbreak of hMPV in an aged care facility in Australia. hPMV should be considered as the possible cause of outbreaks in aged care facilities when influenza and respiratory syncytial virus have been excluded

Nosocomial and community transmission of measles virus Genotype D8 imported by a returning traveller from Nepal

Measles is uncommon in Australia due to effective national vaccination strategies. In mid-2003, a cluster of nine cases of measles occurred in western Sydney. The index case was a 29-year-old traveller recently returned from Nepal. The case presented to hospital and transmitted the disease to two others in the Emergency Department. Further cases resulted from both community and nosocomial transmission. The median age of cases was 24 years, with three cases in children aged under four years. Only one person had a documented history of measles vaccination, a child who had received one dose of vaccine overseas. One case was a 2-month-old infant whose mother was immune and two cases were hospital staff members. Molecular analysis of measles virus isolates from four cases revealed the same D8 genotype, a strain previously identifi ed in Nepal. Staff vaccination strategies implemented as a result of the outbreak were poorly patronised despite nosocomial transmission. As diseases such as measles become rare it is important to thoroughly investigate any outbreaks, and to maintain a high index of suspicion of measles, particularly in travellers presenting with a rash having returned from measles-endemic areas. Genetic analysis is important in tracing the origins of an outbreak, and to confi rm relatedness between cases. The highly infectious nature of measles virus also underscores the need for appropriate infection control in minimising risk of nosocomial transmission. Such policies are of increasing importance with the emergence of novel viruses or the threat of pandemic infl uenza

A randomized study of standard versus double dose oseltamivir for treating influenza in the community

The neuraminidase inhibitors are the treatment of choice for influenza virus infection. Oseltamivir-resistant (OsR) strains of influenza A(H1N1)pdm09 are described, but the effect of higher dose oseltamivir on efficacy, safety and emergence of resistance has not been addressed in the developed setting in outpatients. The objectives of the study were to compare standard dose (SD) versus double dose (DD) oseltamivir regimens for frequency of detecting OsR influenza virus, clinical disease resolution, virological clearance and adverse events.This was an unblinded randomized controlled trial of community-based patients with confirmed influenza. Participants were randomized to a 5-day regimen of either SD or DD oseltamivir.Of 52 participants (aged 4.8-54.8 years), 25 received SD and 27 DD oseltamivir. Clinical resolution did not differ by dosing regimen (P=0.43); neither did virological clearance differ for either influenza A (P=0.20) or B (P=0.70). Adverse events, predominantly gastrointestinal, were greater with DD than SD (P=0.04). One OsR strain was detected prior to treatment and two individuals developed OsR strains during treatment, one each on SD and DD. Those with OsR strains did not appear to have a different clinical course.DD oseltamivir did not appear to provide a clinical or virological advantage, nor reduce the emergence of oseltamivir resistance, but our study was underpowered. Adverse events occurred more frequently on DD compared to SD oseltamivir

Pandemic clinical case definitions are non-specific: multiple respiratory viruses circulating in the early phases of the 2009 influenza pandemic in New South Wales, Australia

BACKGROUND: During the early phases of the 2009 pandemic, subjects with influenza-like illness only had laboratory testing specific for the new A(H1N1)pdm09 virus. FINDINGS: Between 25(th) May and 7(th) June 2009, during the pandemic CONTAIN phase, A(H1N1)pdm09 virus was detected using nucleic acid tests in only 56 of 1466 (3.8%) samples meeting the clinical case definition required for A(H1N1)pdm09 testing. Two hundred and fifty-five randomly selected A(H1N1)pdm09 virus-negative samples were tested for other respiratory viruses using a real-time multiplex PCR assay. Of the 255 samples tested, 113 (44.3%) had other respiratory viruses detected: rhinoviruses 63.7%, seasonal influenza A 17.6%, respiratory syncytial virus 7.9%, human metapneumovirus 5.3%, parainfluenzaviruses 4.4%, influenza B virus 4.4%, and enteroviruses 0.8%. Viral co-infections were present in 4.3% of samples. CONCLUSIONS: In the very early stages of a new pandemic, limiting testing to only the novel virus will miss other clinically important co-circulating respiratory pathogens

Correction: A randomized study of standard versus double dose oseltamivir for treating influenza in the community (Antiviral Therapy (2015) 20 (689–698) DOI: 10.3851/IMP2807)

The publisher would like to report an error that appeared in a published article [1]. On page 692 under the section Virological outcome the sentence ‘There was no difference by dose in virological clearance as determined by culture-negative swabs by visit 2 (SD 20/25, 95.2% versus DD 21/23, 91.3%; P=0.61)’ has been corrected as follows: ‘There was no difference by dose in virological clearance as determined by culture-negative swabs by visit 2 (SD 20/21, 95.2% versus DD 21/23, 91.3%; P=0.61)’. This has been corrected as of 25 October 2018. The authors apologize for this error

Identification of 20 Common Human Enterovirus Serotypes by Use of a Reverse Transcription-PCR-Based Reverse Line Blot Hybridization Assay ▿

The more than 100 human enterovirus (HEV) serotypes can also be classified into four species, HEV-A to -D, based on phylogenetic analysis of multiple gene regions. Current molecular typing methods depend largely on reverse transcription-PCR (RT-PCR) amplification and nucleotide sequencing of the entire or 3′ half of the VP1 gene. An RT-PCR-based reverse line blot (RLB) hybridization assay was developed as a rapid and efficient approach to characterize common HEVs. Twenty HEV serotypes accounted for 87.1% of all HEVs isolated at an Australian reference virology laboratory from 1979 to 2007. VP1 sequences of all known HEV prototype strains were aligned to design one sense primer and three antisense primers for RT-PCR. After sequencing of the complete VP1 genes of 37 previously serotyped examples of the commonest 20 serotypes and alignment of these VP1 sequences with GenBank sequences, four serotype-specific probes for each serotype were designed for RLB. The RT-PCR-RLB assay was then applied to 132 HEV isolates, made up of the previously sequenced 37 isolates and another 95 serotyped clinical isolates. The RT-PCR-RLB genotypes corresponded with the serotypes for 131/132 isolates; the one exception was confirmed by VP1 sequencing, and the genotype was confirmed by repeat conventional serotyping. Genotyping by RT-PCR-RLB complements traditional serotyping methods and VP1 sequencing and has the advantages of convenience, speed, and accuracy. RT-PCR-RLB allows detection of specific enteroviral serotypes or genotypes associated with HEV outbreaks and significant disease