Epidemiology of physical-mental multimorbidity and its impact among Aboriginal and Torres Strait Islander in Australia: a cross-sectional analysis of a nationally representative sample.

OBJECTIVES: This study aimed to examine the differences in multimorbidity between Aboriginal and Torres Strait Islander people and non-Indigenous Australians, and the effect of multimorbidity on health service use and work productivity. SETTING: Cross-sectional sample of the Household, Income and Labour Dynamics in Australia wave 17. PARTICIPANTS: A nationally representative sample of 16 749 respondents aged 18 years and above. OUTCOME MEASURES: Multimorbidity prevalence and pattern, self-reported health, health service use and employment productivity by Indigenous status. RESULTS: Aboriginal respondents reported a higher prevalence of multimorbidity (24.2%) compared with non-Indigenous Australians (20.7%), and the prevalence of mental-physical multimorbidity was almost twice as high (16.1% vs 8.1%). Multimorbidity pattern varies significantly among the Aboriginal and non-Indigenous Australians. Multimorbidity was associated with higher health service use (any overnight admission: adjusted OR=1.52, 95% CI=1.46 to 1.58), reduced employment productivity (days of sick leave: coefficient=0.25, 95% CI=0.19 to 0.31) and lower perceived health status (SF6D score: coefficient=-0.04, 95% CI=-0.05 to -0.04). These associations were found to be comparable in both Aboriginal and non-Indigenous populations. CONCLUSIONS: Multimorbidity prevalence was significantly greater among Aboriginal and Torres Strait Islanders compared with the non-Indigenous population, especially mental-physical multimorbidity. Strategies are required for better prevention and management of multimorbidity for the aboriginal population to reduce health inequalities in Australia.

An internet-delivered handwashing intervention to modify influenza-like illness and respiratory infection transmission (PRIMIT): a primary care randomised trial.

BACKGROUND: Handwashing to prevent transmission of respiratory tract infections (RTIs) has been widely advocated, especially during the H1N1 pandemic. However, the role of handwashing is debated, and no good randomised evidence exists among adults in non-deprived settings. We aimed to assess whether an internet-delivered intervention to modify handwashing would reduce the number of RTIs among adults and their household members. METHODS: We recruited individuals sharing a household by mailed invitation through general practices in England. After consent, participants were randomised online by an automated computer-generated random number programme to receive either no access or access to a bespoke automated web-based intervention that maximised handwashing intention, monitored handwashing behaviour, provided tailored feedback, reinforced helpful attitudes and norms, and addressed negative beliefs. We enrolled participants into an additional cohort (randomised to receive intervention or no intervention) to assess whether the baseline questionnaire on handwashing would affect handwashing behaviour. Participants were not masked to intervention allocation, but statistical analysis commands were constructed masked to group. The primary outcome was number of episodes of RTIs in index participants in a modified intention-to-treat population of randomly assigned participants who completed follow-up at 16 weeks. This trial is registered with the ISRCTN registry, number ISRCTN75058295. FINDINGS: Across three winters between Jan 17, 2011, and March 31, 2013, we enrolled 20,066 participants and randomly assigned them to receive intervention (n=10,040) or no intervention (n=10,026). 16,908 (84%) participants were followed up with the 16 week questionnaire (8241 index participants in intervention group and 8667 in control group). After 16 weeks, 4242 individuals (51%) in the intervention group reported one or more episodes of RTI compared with 5135 (59%) in the control group (multivariate risk ratio 0·86, 95% CI 0·83-0·89; p<0·0001). The intervention reduced transmission of RTIs (reported within 1 week of another household member) both to and from the index person. We noted a slight increase in minor self-reported skin irritation (231 [4%] of 5429 in intervention group vs 79 [1%] of 6087 in control group) and no reported serious adverse events. INTERPRETATION: In non-pandemic years, an effective internet intervention designed to increase handwashing could have an important effect in reduction of infection transmission. In view of the heightened concern during a pandemic and the likely role of the internet in access to advice, the intervention also has potential for effective implementation during a pandemic. FUNDING: Medical Research Council.

Longevity and determinants of protective humoral immunity after pandemic influenza infection.

RATIONALE: Antibodies to influenza hemagglutinin are the primary correlate of protection against infection. The strength and persistence of this immune response influences viral evolution and consequently the nature of influenza epidemics. However, the durability and immune determinants of induction of humoral immunity after primary influenza infection remain unclear. OBJECTIVES: The spread of a novel H1N1 (A[H1N1]pdm09) virus in 2009 through an unexposed population offered a natural experiment to assess the nature and longevity of humoral immunity after a single primary influenza infection. METHODS: We followed A(H1N1)pdm09-seronegative adults through two influenza seasons (2009-2011) as they developed A(H1N1)pdm09 influenza infection or were vaccinated. Antibodies to A(H1N1)pdm09 virus were measured by hemagglutination-inhibition assay in individuals with paired serum samples collected preinfection and postinfection or vaccination to assess durability of humoral immunity. Preexisting A(H1N1)pdm09-specific multicytokine-secreting CD4 and CD8 T cells were quantified by multiparameter flow cytometry to test the hypothesis that higher frequencies of CD4(+) T-cell responses predict stronger antibody induction after infection or vaccination. MEASUREMENTS AND MAIN RESULTS: Antibodies induced by natural infection persisted at constant high titer for a minimum of approximately 15 months. Contrary to our initial hypothesis, the fold increase in A(H1N1)pdm09-specific antibody titer after infection was inversely correlated to the frequency of preexisting circulating A(H1N1)pdm09-specific CD4(+)IL-2(+)IFN-γ(-)TNF-α(-) T cells (r = -0.4122; P = 0.03). CONCLUSIONS: The longevity of protective humoral immunity after influenza infection has important implications for influenza transmission dynamics and vaccination policy, and identification of its predictive cellular immune correlate could guide vaccine development and evaluation.

Incidence of influenza A(H1N1)pdm09 infection, United Kingdom, 2009-2011.

We conducted a longitudinal community cohort study of healthy adults in the UK. We found significantly higher incidence of influenza A(H1N1)pdm09 infection in 2010-11 than in 2009-10, a substantial proportion of subclinical infection, and higher risk for infection during 2010-11 among persons with lower preinfection antibody titers.

Cellular immune correlates of protection against symptomatic pandemic influenza.

The role of T cells in mediating heterosubtypic protection against natural influenza illness in humans is uncertain. The 2009 H1N1 pandemic (pH1N1) provided a unique natural experiment to determine whether crossreactive cellular immunity limits symptomatic illness in antibody-naive individuals. We followed 342 healthy adults through the UK pandemic waves and correlated the responses of pre-existing T cells to the pH1N1 virus and conserved core protein epitopes with clinical outcomes after incident pH1N1 infection. Higher frequencies of pre-existing T cells to conserved CD8 epitopes were found in individuals who developed less severe illness, with total symptom score having the strongest inverse correlation with the frequency of interferon-γ (IFN-γ)(+) interleukin-2 (IL-2)(-) CD8(+) T cells (r = -0.6, P = 0.004). Within this functional CD8(+)IFN-γ(+)IL-2(-) population, cells with the CD45RA(+) chemokine (C-C) receptor 7 (CCR7)(-) phenotype inversely correlated with symptom score and had lung-homing and cytotoxic potential. In the absence of crossreactive neutralizing antibodies, CD8(+) T cells specific to conserved viral epitopes correlated with crossprotection against symptomatic influenza. This protective immune correlate could guide universal influenza vaccine development.

A hepatitis C avidity test for determining recent and past infections in both plasma and dried blood spots.

BACKGROUND: DBS testing has been used successfully to detect HCV antibody positive individuals. Determining how long someone has been infected is important for surveillance initiatives. Antibody avidity is a method that can be used to calculate recency of infection. OBJECTIVES: A HCV avidity assay was evaluated for both plasma and DBS. STUDY DESIGN: To measure antibody avidity a commercial HCV ELISA was modified using 7 M urea. The plasma samples were split into: group 1 (recently infected N = 19), group 2 (chronic carrier N = 300) and group 3 (resolved infection N = 82). Mock DBS made from group 1 (N = 12), group 2 (N = 50), group 3 (N = 25) and two seroconverter panels were evaluated. 133 DBS taken from patients known to have a resolved infection or be a chronic carrier were also tested. RESULTS: The avidity assay cut-off was set at AI≤30 for a recent infection. Using sequential samples the assay could detect a recent infection in the first 4-5 months from the point of infection. Most of the false positive results (AI < 30 among cases known not to have had recent infection) were detected among known resolved infections, in both the plasma and DBS; as a result, a testing algorithm has been designed incorporating both PCR and two dilution factors. The sensitivity and specificity of the assay on plasma was 100% and 99.3%, respectively, while DBS had 100% sensitivity and 98.3% specificity. CONCLUSION: The HCV avidity assay can be used to distinguish between chronic and recent infection using either plasma or DBS as the sample type.

The development of a multiplex real-time PCR for the detection of herpes simplex virus 1 and 2, varizella zoster virus, adenovirus and Chlamydia trachomatis from eye swabs.

Infectious conjunctivitis can be difficult to distinguish clinically due to the considerable overlap in clinical presentation so clinical diagnosis of conjunctivitis is often insufficient. It is therefore necessary to have a rapid diagnostic test that differentiates between the different causes of infectious conjunctivitis. Screening clinical samples by sample type/syndrome based multiplex real time PCR would allow for rapid detection of a variety of pathogens simultaneously, which will in turn aid in the treatment and clinical management of the patient. A multiplex real-time PCR assay for rapid and simultaneous detection of HSV 1 and 2, VZV, adenovirus and Chlamydia trachomatis (C. trachomatis) from eye swabs was developed and evaluated. The multiplex assay was shown to be sensitive, specific and robust. Reductions in sample turn around times have been achieved by reducing the amount of separate tests needed to be carried out.

HBsAg variants: diagnostic-escape and diagnostic dilemma.

A wide variety of commercial assays is available for the detection of hepatitis B surface antigen (HBsAg). Clearly, the sensitivity of an assay to detect a variant is dependent on the anti-HBs usage. Thus, it is not surprising that there are examples of variants that cannot be detected by all assays. Data from Europe, Asia and Africa about HBsAg variants which are not recognized by either monoclonal or polyclonal antibodies specific for wild-type group 'a' determinant, but positive by DNA polymerase chain reaction (PCR) in chronic patients and from vaccinated children are increasing. This would impose a challenge for public health issues of hepatitis B virus. In this review we tried to summarize the discrepancies between results of HBsAg assays and to explain some rationales for these inconsistencies.

Development and assay of RNA transcripts of enterovirus species A to D, rhinovirus species a to C, and human parechovirus: assessment of assay sensitivity and specificity of real-time screening and typing methods.

Nucleic acid amplification methods such as the PCR have had a major impact on the diagnosis of viral infections, often achieving greater sensitivities and shorter turnaround times than conventional assays and an ability to detect viruses refractory to conventional isolation methods. Their effectiveness is, however, significantly influenced by assay target sequence variability due to natural diversity and rapid sequence changes in viruses that prevent effective binding of primers and probes. This was investigated for a diverse range of enteroviruses (EVs; species A to D), human rhinoviruses (HRVs; species A to C), and human parechovirus (HPeV) in a multicenter assay evaluation using a series of full-length prequantified RNA transcripts. RNA concentrations were quantified by absorption (NanoDrop) and fluorescence methods (RiboGreen) prior to dilution in buffer supplemented with RNase inhibitors and carrier RNA. RNA transcripts were extremely stable, showing minimal degradation after prolonged storage at temperatures between ambient and -20°C and after multiple freeze-thaw cycles. Transcript dilutions distributed to six referral laboratories were screened by real-time reverse transcriptase PCR assays using different primers and probes. All of the laboratories reported high assay sensitivities for EV and HPeV transcripts approaching single copies and similar amplification kinetics for all four EV species. HRV detection sensitivities were more variable, often with substantially impaired detection of HRV species C. This could be accounted for in part by the placement of primers and probes to genetically variable target regions. Transcripts developed in this study provide reagents for the ongoing development of effective diagnostics that accommodate increasing knowledge of genetic heterogeneity of diagnostic targets.

Detection of hepatitis C virus RNA in dried blood spots.

BACKGROUND: An estimated 130-170 million people worldwide are chronically infected with HCV.(1) In Europe the highest prevalence of HCV infections is in the IDU population.(2) As traditional HCV screening relies on the detection of HCV antibody or HCV RNA in blood, screening in high-risk groups such as IDU is difficult due to poor venous access caused by damaged veins. OBJECTIVES: In this study DBS was evaluated as an alternative sample type to blood for the detection of HCV RNA. STUDY DESIGN: The endpoint detection limit, inter-assay and intra-assay variability of the method were determined. The DBS method was compared to our routine frontline assay using a panel of paired DBS and blood samples. The effect of different storage temperatures and length of storage time on the stability of HCV RNA in DBS was also assessed. RESULTS: The endpoint detection limit of the method based on results from mock DBS was 250 IU/ml. The method was shown to be precise and robust. The sensitivity and specificity of the method was found to be 100% and 95.8%, respectively. No significant variation in the stability of HCV RNA in DBS over a 1 year period at a range of different temperatures was observed. CONCLUSIONS: A sensitive and stable method was developed for the detection of HCV RNA in DBS. Screening high-risk populations using DBS as a sample type may improve uptake of HCV testing by increasing opportunity for patients to be tested and consequently increasing access to treatment.

Origin and fate of A/H1N1 influenza in Scotland during 2009.

The spread of influenza has usually been described by a 'density' model, where the largest centres of population drive the epidemic within a country. An alternative model emphasizing the role of air travel has recently been developed. We have examined the relative importance of the two in the context of the 2009 H1N1 influenza epidemic in Scotland. We obtained genome sequences of 70 strains representative of the geographical and temporal distribution of H1N1 influenza during the summer and winter phases of the pandemic in 2009. We analysed these strains, together with another 128 from the rest of the UK and 292 globally distributed strains, using maximum-likelihood phylogenetic and bayesian phylogeographical methods. This revealed strikingly different epidemic patterns within Scotland in the early and late parts of 2009. The summer epidemic in Scotland was characterized by multiple independent introductions from both international and other UK sources, followed by major local expansion of a single clade that probably originated in Birmingham. The winter phase, in contrast, was more diverse genetically, with several clades of similar size in different locations, some of which had no particularly close phylogenetic affinity to strains sampled from either Scotland or England. Overall there was evidence to support both models, with significant links demonstrated between North American sequences and those from England, and between England and East Asia, indicating that major air-travel routes played an important role in the pattern of spread of the pandemic, both within the UK and globally.

Prevalence of influenza A (H1N1) seropositivity in unvaccinated healthcare workers in Scotland at the height of the global pandemic.

BACKGROUND: We set out to identify the level of previous exposure to influenza A (H1N1) in unvaccinated healthcare workers (HCWs) at the peak of the pandemic outbreak in the UK, with control samples collected prior to the outbreak. METHODS: Cross-sectional study (seroprevalence assessed before and at pandemic peak, with questionnaire data collected at peak of outbreak) in HCWs in Scotland. RESULTS: The prevalence of seropositivity in 493 HCWs at pandemic peak was 10.3%, which was higher than the prepandemic level by 3.7 percentage points (95% CI 0.3% to 7.3%, P = 0.048). Seropositivity rates for frontline and nonfrontline HCWs were similar. CONCLUSION: At pandemic peak, only 10.3% of HCWs were seropositive for influenza A (H1N1), so the great majority were still susceptible to infection at the introduction of the vaccination programme. Few studies have reported on seroprevalence in unvaccinated and asymptomatic participants, so our findings may have relevance to the wider population.

During the summer 2009 outbreak of "swine flu" in Scotland what respiratory pathogens were diagnosed as H1N1/2009?

BACKGROUND: During the April-July 2009 outbreak of H1N1/2009 in scotland the West of Scotland Specialist Virology Centre (WoSSVC) in Glasgow tested > 16,000 clinical samples for H1N1/2009. Most were from patients clinically diagnosed with H1N1/2009. Out of these, 9% were positive. This study sought to determine what respiratory pathogens were misdiagnosed as cases of H1N1/2009 during this time. METHODS: We examined the results from 3247 samples which were sent to the laboratory during April-July 2009. All were from patients clinically diagnosed as having H1N1/2009 (based on accepted criteria) and all were given a full respiratory screen using real time reverse transcriptase polymerase chain reaction (rtRT-PCR) assays. RESULTS: In total, respiratory pathogens were detected in 27.9% (95% confidence interval, 26.3-29.5%) of the samples submitted. Numerous pathogens were detected, the most common of which were rhinovirus (8.9% (95% confidence interval, 7.9-9.9%)), parainfluenza 1 (1.9% (95% confidence interval, 1.4-2.4%)) and 3 (4.1% (95% confidence interval, 3.3-4.9%)), and adenovirus ((3.5% (95% confidence interval, 2.9-4.2%)). CONCLUSIONS: This study highlights the problems of using a clinical algorithm to detect H1N1/2009. Clinicians frequently misdiagnosed common respiratory pathogens as H1N1/2009 during the spring/summer outbreak in Scotland. Many undesirable consequences would have resulted, relating to treatment, infection control, and public health surveillance.

Sero-prevalence and incidence of A/H1N1 2009 influenza infection in Scotland in winter 2009-2010.

BACKGROUND: Sero-prevalence is a valuable indicator of prevalence and incidence of A/H1N1 2009 infection. However, raw sero-prevalence data must be corrected for background levels of cross-reactivity (i.e. imperfect test specificity) and the effects of immunisation programmes. METHODS AND FINDINGS: We obtained serum samples from a representative sample of 1563 adults resident in Scotland between late October 2009 and April 2010. Based on a microneutralisation assay, we estimate that 44% (95% confidence intervals (CIs): 40-47%) of the adult population of Scotland were sero-positive for A/H1N1 2009 influenza by 1 March 2010. Correcting for background cross-reactivity and for recorded vaccination rates by time and age group, we estimated that 34% (27-42%) were naturally infected with A/H1N1 2009 by 1 March 2010. The central estimate increases to >40% if we allow for imperfect test sensitivity. Over half of these infections are estimated to have occurred during the study period and the incidence of infection in late October 2009 was estimated at 4.3 new infections per 1000 people per day (1.2 to 7.2), falling close to zero by April 2010. The central estimate increases to over 5.0 per 1000 if we allow for imperfect test specificity. The rate of infection was higher for younger adults than older adults. Raw sero-prevalences were significantly higher in more deprived areas (likelihood ratio trend statistic = 4.92,1 df, P = 0.03) but there was no evidence of any difference in vaccination rates. CONCLUSIONS: We estimate that almost half the adult population of Scotland were sero-positive for A/H1N1 2009 influenza by early 2010 and that the majority of these individuals (except in the oldest age classes) sero-converted as a result of natural infection with A/H1N1 2009. Public health planning should consider the possibility of higher rates of infection with A/H1N1 2009 influenza in more deprived areas.

Rapid simultaneous detection of enterovirus and parechovirus RNAs in clinical samples by one-step real-time reverse transcription-PCR assay.

Enteroviruses (EVs) are recognized as the major etiological agent in meningitis in children and young adults. The use of molecular techniques, such as PCR, has substantially improved the sensitivity of enterovirus detection compared to that of virus culture methods. PCR-based methods also can detect a much wider range of EV variants, including those within species A, as well as human parechoviruses (HPeVs) that often grow poorly in vitro and which previously have been underdiagnosed by traditional methods. To exploit these developments, we developed a real-time one-step reverse transcription-PCR (RT-PCR) for the rapid and sensitive detection of EV and HPeV in clinical specimens. Two commercially available RT-PCR kits were used (method I, Platinum one-step kit; method II, Express qPCR one-step kit) with primers and probes targeting the EV and HPeV 5'-untranslated regions (5'UTR). Amplification dynamics (threshold cycle [C(T)]values and efficiencies) of absolutely quantified full-length RNA transcripts representative of EV species A to D and HPeV were similar, demonstrating the effectiveness of both assays across the range of currently described human EV and HPeV variants. Probit analysis of multiple endpoint replicates demonstrated comparable sensitivities of the assays for EV and HPeV (method I, approximately 10 copies per reaction for both targets; method II, 20 copies per reaction). C(T) values were highly reproducible on repeat testing of positive controls within assays and between assay runs. Considering the sample turnaround time of less than 3 h, the multiplexed one-step RT-PCR method provides rapid diagnostic testing for EV and HPeV in cases of suspected central nervous system infections in a clinically relevant time frame.

The validation of a real-time RT-PCR assay which detects influenza A and types simultaneously for influenza A H1N1 (2009) and oseltamivir-resistant (H275Y) influenza A H1N1 (2009).

Influenza A H1N1 (2009) was declared by the World Health Organisation (WHO) as the first influenza pandemic of the 21st century. Rapid detection of influenza A and differentiation of influenza A H1N1 (2009) and seasonal influenza A is beneficial. In addition the rapid detection of antiviral resistant strains of influenza A H1N1 (2009) would be useful for clinicians to allow for change to an effective treatment at a much earlier stage if resistance is found. It was the aim of this study to develop a real-time RT-PCR that can detect all influenza A viruses and type simultaneously for influenza A H1N1 (2009) and oseltamivir resistant (H275Y) influenza A H1N1 (2009). This multiplex assay will allow laboratories to screen respiratory samples for all types of influenza A, influenza A H1N1 (2009) virus and oseltamivir resistant (H275Y) influenza A H1N1 (2009) virus in a rapid and cost effective format, ensuring that typing methods for seasonal and avian viruses are used on a smaller subset of samples. Since most virology laboratories already offer a molecular service for influenza A this assay could easily be implemented into most areas at little cost therefore increasing local access to resistance testing.

A new multiplex real-time PCR test for HSV1/2 and syphilis: an evaluation of its impact in the laboratory and clinical setting.

OBJECTIVES: To develop, evaluate and implement a new multiplex real-time PCR test for the detection of herpes simplex virus (HSV)1, HSV2 and syphilis in a single sample using a single test. METHODS: A multiplex real-time PCR test detecting HSV1, HSV2 and Treponema pallidum was designed, validated and evaluated for a period of 6 months on patients attending the Sandyford Initiative (a series of genitourinary medicine clinics in and around Glasgow). A total of 692 samples were tested, and T pallidum PCR positives were confirmed by a second PCR at the Scottish Reference Laboratory (SBSTIRL). All PCR results were aligned with dark ground microscopy findings and serological results where available and compared. RESULTS: The laboratory validation of the multiplex assay showed the test to be sensitive, specific and robust. Of the 692 samples, 139 were positive for HSV1, 136 for HSV2, 15 for syphilis, one for both syphilis and HSV1, and 401 were negative; the reference laboratory confirmed all T pallidum PCR-positive samples. The PCR test was more sensitive than both dark ground microscopy and serological testing for the diagnosis of primary syphilis. CONCLUSIONS: The introduction of this new test has led to a better turnaround time for the diagnosis of genital ulcer disease, better detection of primary syphilis infection, and the detection of unexpected cases of syphilis where the aetiological agent suspected was HSV.

Reduction of natural killer but not effector CD8 T lymphocytes in three consecutive cases of severe/lethal H1N1/09 influenza A virus infection.

BACKGROUND: The cause of severe disease in some patients infected with pandemic influenza A virus is unclear. METHODOLOGY/PRINCIPAL FINDINGS: We present the cellular immunology profile in the blood, and detailed clinical (and post-mortem) findings of three patients with rapidly progressive infection, including a pregnant patient who died. The striking finding is of reduction in natural killer (NK) cells but preservation of activated effector CD8 T lymphocytes; with viraemia in the patient who had no NK cells. Comparison with control groups suggests that the reduction of NK cells is unique to these severely ill patients. CONCLUSION/SIGNIFICANCE: Our report shows markedly reduced NK cells in the three patients that we sampled and raises the hypothesis that NK may have a more significant role than T lymphocytes in controlling viral burden when the host is confronted with a new influenza A virus subtype.

A low density oligonucleotide microarray for the detection of viral and atypical bacterial respiratory pathogens.

Acute respiratory tract infections are a major cause of morbidity and mortality worldwide and exert a considerable economic burden on healthcare systems. Acute respiratory tract infections of the upper and lower respiratory tract are caused by a wide variety of viral and bacterial pathogens, which require comprehensive laboratory investigations. Conventional serological and immunofluorescence-based diagnostic methods for acute respiratory tract infections lack sensitivity when compared to polymerase chain reaction (PCR)-based approaches and the development of new diagnostic methodologies is required, to provide accurate, sensitive and rapid diagnoses. In the present study, a PCR-based low density oligonucleotide microarray was developed for the detection of 16 viral and two atypical bacterial pathogens. The performance of this DNA microarray-based analysis exhibited comparable sensitivities and specificities to multiplex real-time reverse transcription polymerase chain reactions (rtPCRs) confirming the potential diagnostic utility of the method. In contrast to routine multiplex PCR, the microarray incorporates an intrinsic redundancy as multiple and non-identical probes per target on the array allow direct intra-assay confirmation of positives. This study demonstrates that microarray technology provides a viable alternative to conventional serological-based approaches and multiplex PCR for pathogen identification in acute respiratory tract infections.