Kenneth McPhie

Influenza Virus A (H10N7) in Chickens and Poultry Abattoir Workers, Australia

In March 2010, an outbreak of low pathogenicity avian influenza A (H10N7) occurred on a chicken farm in Australia. After processing clinically normal birds from the farm, 7 abattoir workers reported conjunctivitis and minor upper respiratory tract symptoms. Influenza virus A subtype H10 infection was detected in 2 workers.

Comparison of a Rapid Antigen Test with Nucleic Acid Testing during Cocirculation of Pandemic Influenza A/H1N1 2009 and Seasonal Influenza A/H3N2

ABSTRACT The rapid diagnosis of influenza is critical in optimizing clinical management. Rapid antigen tests have decreased sensitivity in detecting pandemic influenza A/H1N1 2009 virus compared to seasonal influenza A subtypes (53.4% versus 74.2%, P < 0.001). Nucleic acid tests should be used to detect pandemic influenza virus when rapid antigen tests are negative.

Molecular epidemiology of enterovirus 71 over two decades in an Australian urban community.

Summary.Enterovirus 71 (EV71), first isolated in 1969, has been responsible for numerous outbreaks of hand, foot and mouth disease (HFMD) with a small proportion of cases associated with neurological disease. Since 1997 there has been a significant increase in both the prevalence and virulence of EV71 in the Asia-Pacific region. We have examined the genetic diversity of EV71 in a large Australian city (Sydney N.S.W.) over a nineteen-year period. We determined the VP1 gene sequence of forty-eight EV71 strains isolated between 1983 and 2001. Analysis by molecular phylogeny revealed the presence of four subgenogroups B2, B4, C1 and C2. The results indicate that the major lineage circulating in Sydney N.S.W. was subgenogroup C1 with a recent switch in dominance to B4 in 2000 and 2001.

Increase in rates of herpes simplex virus type 1 as a cause of anogenital herpes in western Sydney, Australia, between 1979 and 2003

Backgound/objective: Recent studies suggest that herpes simplex virus type 1 (HSV-1) is becoming more common as a cause for genital herpes, relative to HSV-2. We aimed to calculate trends in HSV type from isolates and serology samples sent to a reference virology laboratory in New South Wales (NSW), Australia. Methods: We compared the proportions of HSV-1 and HSV-2 positive samples, adjusting for age and sex of source patient, in three datasets: anogenital isolates from 1979 to 1988; anogenital isolates from 1989 to 2003; and HSV type specific IgM seropositivity from 1994 to 2003. Results: The number of specimens in each analysis was 17 512, 4359, and 497, respectively. There was a progressive rise in the proportions of typed specimens being HSV-1 in all analyses. The proportion of isolates that were HSV-1 ranged from 3% in 1980 to 41% in 2001. Female sex and age under 25 were associated with a greater proportion of HSV-1 isolates in both time periods. In the period 1979–88, comparing the proportions of HSV-1 and HSV-2 gave an odds ratio (OR) per additional year of 1.24 (95% confidence interval (CI) 1.20 to 1.27; p<0.005) after adjustment for age and sex. In the period 1989–2003 there was a steeper rise in the proportion of isolates that were HSV-1 in samples from younger individuals (OR per year 1.17, 1.12 to 1.22) compared to those over 25 (OR per year 1.06, 1.03 to 1.08). The rise in the proportion of IgM seropositive results reactive for HSV-1 compared to HSV-2 gave an OR of 1.36 per year (1.26 to 1.47; p<0.005). Conclusions: These data suggest that HSV-1 has become more common as a cause of anogenital herpes in NSW.

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

BackgroundInfluenza 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.MethodsWe 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.ResultsThe 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.ConclusionsMT-PCR is a potentially powerful tool for the differential diagnosis of influenza-like illness in the clinical diagnostic laboratory.

Evaluation of twenty rapid antigen tests for the detection of human influenza A H5N1, H3N2, H1N1, and B viruses.

Twenty rapid antigen assays were compared for their ability to detect influenza using dilutions of virus culture supernatants from human isolates of influenza A H5N1 (clade 1 and 2 strains), H3N2 and H1N1 viruses, and influenza B. There was variation amongst the rapid antigen assays in their ability to detect different influenza viruses. Six of the 12 assays labeled as distinguishing between influenza A and B had comparable analytical sensitivities for detecting both influenza A H5N1 strains, although their ability to detect influenza A H3N2 and H1N1 strains varied. The two assays claiming H5 specificity did not detect either influenza A H5N1 strains, and the two avian influenza‐specific assays detected influenza A H5N1, but missed some influenza A H3N2 virus supernatants. Clinical trials of rapid antigen tests for influenza A H5N1 are limited. For use in a pandemic where novel influenza strains are circulating (such as the current novel influenza A H1N1 09 virus), rapid antigen tests should ideally have comparable sensitivity and specificity for the new strains as for co‐circulating seasonal influenza strains. J. Med. Virol. 81:1918–1922, 2009.

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.

An outbreak of epidemic keratoconjunctivitis in a regional ophthalmology clinic in New South Wales

The objective of the study was to identify the extent and cause of an outbreak of epidemic keratoconjunctivitis (EKC). The study design was active case finding and a case-control study of clinic patients who developed symptoms of EKC between 31 December 2005 and 31 March 2006. The main outcome measures were clinical procedures carried out and clinicians seen during clinic visit. Significantly more cases than controls had tonometry with instillation of anaesthetic drops (OR 16.5, 95% CI 3.9-145.1, P<0.01), optical coherence tomography (OR 4.7, 95% CI 1.2-21.9, P=0.01), or instillation of dilating drops by an orthoptist (OR 2.3, 95% CI 1.1-4.7, P=0.01). Significantly more cases than controls were seen by one orthoptist (OR 21.8, 95% CI 8.2-60.0, P<0.01). Transmission of EKC within the clinic was probably due to contamination of either or both the anaesthetic drops and the tonometer head in the room used by an orthoptist. A comprehensive suite of strategies is required to prevent healthcare-associated EKC.

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

ABSTRACT 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.