Differentiation of influenza B lineages from clinical samples by one-step real-time RT-PCR.

BACKGROUND: Influenza viruses type A and type B are a leading cause of annual epidemics in human populations. Since the 1970s, influenza B viruses have diverged into two antigenically distinct virus lineages called the Yamagata and Victoria lineages. We describe the validation and implementation of a one-step real-time RT-PCR (rRT-PCR) assay that can differentiate between the two genetic lineages of type B. METHODS: Validation of rRT-PCR method was carried out using quantified positive control and reference influenza viruses with specific minor groove binder (MGB) probes. The assay was applied on 102 clinical specimens detected positive for influenza type B. RESULTS: Detection limit was found to be as low as 7.95 RNA copies per reaction. The interassay variability and intra-assay variability were found to be low, and comparable for Yamagata and Victoria lineages. No cross-reactivity with the tested subtypes of influenza type A, known to cause human infections, was noticed. Differentiation of influenza B lineages by rRT-PCR was successfully achieved on all of the known positive type B samples. From the total number of clinical specimens tested, 85 samples belonged to B/Yamagata and 17 samples to B/Victoria lineage. CONCLUSION: Differentiation of genetic lineage B influenza virus circulating in Romania in the next seasons by one-step real-time RT-PCR method will supplement the classical test, haemagglutination inhibition (HI), which requires growing of the virus. This method can be advantageous for a balanced selection of samples, in case of lineages co-circulation, for genetic and antigenic characterization.

Survival of H5N1 influenza virus in water and its inactivation by chemical methods.

The ability of H5N1 Avian Influenza Virus (AIV) to survive in surface water has been assessed in experimental laboratory conditions, based on non-pathogenic avian reassortant model, by titration of infectivity (TCID50) at different time intervals, in three different types of water. The effect of different chemicals on AIV's survival was assessed using the same type of experimental model. After exposure to the chemical, followed by growth on a suitable substrate, the AIV was quantified by a real-time quantitative reverse transcriptase PCR (qRT-PCR). The reassortant virus persisted, and remained infective in aquatic environments, for 12 days at 22-35 degrees C and up to 20 days at 4 degrees C, irrespective of the type of water, supporting the hypothesis of a potential risk for transmitting the virus among birds and contaminating the household water via common sources of water. A significant decrease for AIV persistence models was recorded for sea water, after 12 days, at 35 degrees C. An effective inactivation has been shown when using commercially available products based on glutaraldehyde and penta potassium bis (peroxy mono sulphate) bis(sulphate), respectively. This rapid and safe method for decontamination, developed in this study, might be helpful in implementation of biosafety measures in laboratory and farms against AIV.

Surveillance of medically-attended influenza in elderly patients from Romania-data from three consecutive influenza seasons (2015/16, 2016/17, and 2017/18).

BACKGROUND: Influenza is an acute infection affecting all age groups; however, elderly patients are at an increased risk. We aim to describe the clinical characteristics and the circulation of influenza virus types in elderly patients admitted for severe acute respiratory infection (SARI) to a tertiary care hospital in Bucharest, Romania, part of the I-MOVE+ hospital network. METHODS: We conducted an active surveillance study at the National Institute for Infectious Diseases "Prof. Dr Matei Balș," Bucharest, Romania, during three consecutive influenza seasons: 2015/16, 2016/17, and 2017/18. All patients aged 65 and older admitted to our hospital for SARI were tested for influenza by PCR. RESULTS: A total of 349 eligible patients were tested during the study period, and 149 (42.7%) were confirmed with influenza. Most patients, 321 (92.5%) presented at least one underlying condition at the time of hospital admission, the most frequent being cardiovascular disease, 270 (78.3%). The main influenza viral subtype circulating in 2015/16 was A(H1N1)pdm09, followed by A(H3N2) in 2016/17 and B influenza in 2017/18. Case fatality was highest in the 2015/16 season (3.7%), 0% in 2016/17, and 1.0% in 2017/18. Vaccination coverage in elderly patients with SARI from our study population was 22 (6.3%) over the three seasons. CONCLUSIONS: Our study has highlighted a high burden of comorbidities in elderly patients presenting with SARI during winter season in Romania. The influenza vaccine coverage rate needs to be substantially increased in the elderly population, through targeted interventions.

Characteristics of influenza in elderly patients with and without diabetes, hospitalized for severe acute respiratory infection in a tertiary care hospital from Bucharest Romania - a three-year prospective epidemiological surveillance study.

INTRODUCTION: Patients with diabetes may be at a higher risk of developing complicated influenza. We report the characteristics of influenza in hospitalized elderly patients with and without diabetes, in three consecutive influenza seasons. METHODS: The study included patients admitted for severe acute respiratory infection (SARI) in the National Institute for Infectious Diseases "Prof. Dr. Matei Balș", Bucharest, during a three-year active epidemiological surveillance study (2015/16, 2016/17, 2017/18), in the I-MOVE+ hospital network. RESULTS: A total of 349 patients were tested by PCR over the duration of the study. The percentage of patients with diabetes was comparable throughout the seasons: 34.7%, 28.3% and 30.4% (p=0.587). Influenza A was the main viral type circulating in 2015/16 and 2016/17 (100% and 97.6%) in our study population, while in 2017/18, B viruses predominated (90.0%). Diabetics presented a higher median number of comorbidities (3 vs. 2) p<0.001, and two-fold higher odds of also associating obesity (OR=2.1, 95%CI:1.3-3.4, p=0.003), compared to those without diabetes. Diabetics also tested positive for influenza more often (p=0.296). Only 6 patients with diabetes (5.4%) from our study had been vaccinated against influenza, and most (n=4) of those who had been vaccinated tested negative for influenza. CONCLUSIONS: Our study is the first to describe the circulation of influenza viral types in elderly diabetic patients hospitalized for SARI. The results reinforce the national and international recommendation to vaccinate against influenza all patients with diabetes.

Severe acute respiratory infections surveillance in Romania - is it any gain to public health?

UNLABELLED: This article aims to present the operation and usefulness of severe acute respiratory infection (SARI) surveillance in Romania. Material and methods : The information obtained from surveillance data analysis using Epilnfo program revealed a greater severity of influenza in the second post-pandemic season (2011/2012) compared to the previous one (2010/2011). Detected risk factors were evidence-based arguments for recommending preventive measures in certain population groups. CONCLUSIONS: This surveillance system has proven useful, being able to provide information on the severity of influenza and other etiologies involved in severe acute respiratory infections.

I-MOVE multi-centre case control study 2010-11: overall and stratified estimates of influenza vaccine effectiveness in Europe.

BACKGROUND: In the third season of I-MOVE (Influenza Monitoring Vaccine Effectiveness in Europe), we undertook a multicentre case-control study based on sentinel practitioner surveillance networks in eight European Union (EU) member states to estimate 2010/11 influenza vaccine effectiveness (VE) against medically-attended influenza-like illness (ILI) laboratory-confirmed as influenza. METHODS: Using systematic sampling, practitioners swabbed ILI/ARI patients within seven days of symptom onset. We compared influenza-positive to influenza laboratory-negative patients among those meeting the EU ILI case definition. A valid vaccination corresponded to > 14 days between receiving a dose of vaccine and symptom onset. We used multiple imputation with chained equations to estimate missing values. Using logistic regression with study as fixed effect we calculated influenza VE adjusting for potential confounders. We estimated influenza VE overall, by influenza type, age group and among the target group for vaccination. RESULTS: We included 2019 cases and 2391 controls in the analysis. Adjusted VE was 52% (95% CI 30-67) overall (N = 4410), 55% (95% CI 29-72) against A(H1N1) and 50% (95% CI 14-71) against influenza B. Adjusted VE against all influenza subtypes was 66% (95% CI 15-86), 41% (95% CI -3-66) and 60% (95% CI 17-81) among those aged 0-14, 15-59 and ≥60 respectively. Among target groups for vaccination (N = 1004), VE was 56% (95% CI 34-71) overall, 59% (95% CI 32-75) against A(H1N1) and 63% (95% CI 31-81) against influenza B. CONCLUSIONS: Results suggest moderate protection from 2010-11 trivalent influenza vaccines against medically-attended ILI laboratory-confirmed as influenza across Europe. Adjusted and stratified influenza VE estimates are possible with the large sample size of this multi-centre case-control. I-MOVE shows how a network can provide precise summary VE measures across Europe.