Cases Of Pandemic Influenza H1N1 Research Articles

Clinical Evaluation of Cases of Pandemic H1N1 Influenza in Sanliurfa Province in Epidemic Period

Amaç: Bu çalışmada; influenza benzeri hastalık tanımına uyan ve hastaneye yatırılan 75 olgu ile ilgili deneyimlerimizin paylaşılması amaçlandı.Hastalar ve Yöntem: PZR (polimeraz zincir reaksiyonu) yöntemiyle RNA (ribonükleik asit) tespit edilmiş pandemik 2009 influenza pozitif olgular ile negatif olguların yaş, cinsiyet ve altta yatan hastalık ilişkileri, laboratuvar ve radyolojik görüntüleme sonuçları, hastanede ve yoğun bakımda yatış süreleri ve taburculuk şekilleri karşılaştırıldı. Bulgular: Her iki grup arasında cinsiyet dağılımı, yaş ve akciğer grafisi bulguları açısından anlamlı bir fark görülmedi. Gruplar arası laboratuvar parametrelerinden CRP(C-reaktif protein) ve platelet düzeyleri karşılaştırıldığında arada anlamlı fark bulunurken beyaz küre, hemoglobin, nötrofil ve lenfosit sayıları açısından arada anlamlı fark bulunmadı. H1N1 pozitif grupta ortalama CRP miktarı H1N1 negatif gruba göre anlamlı olarak daha yüksek düzeyde bulundu. H1N1 pozitif grupta ortalama platelet miktarı anlamlı olarak H1N1 negatif gruba göre daha düşük bulundu. Sonuç: Pandemik H1N1 influenza olgularının klinik takipleri oldukça önemlidir. Altta yatan kronik hastalık zemininde pandemik influenzanın (H1N1) bazı vakalarda fatal seyredebileceği düşünüldü.

Pulmonary changes in Norwegian fatal cases of pandemic influenza H1N1 (2009) infection: a morphologic and molecular genetic study.

BackgroundDuring the pandemic outbreak of the 2009 swine influenza (A(H1N1)pdm09), 32 fatal cases occurred in Norway and 19 of these were included in this study.ObjectivesWe characterised pulmonary changes in these fatal Norwegian cases.Patients and MethodsUpon hospitalisation, detailed clinical information and specimens from the upper and lower respiratory pathways were collected. At post‐mortem, lung tissue was collected, formalin‐fixed and paraffin‐embedded. Immunohistochemical and light microscopic examination was performed to visualise the local expression of the A(H1N1)pdm09 virus. Reverse transcription‐polymerase chain reaction (RT‐PCR) and pyrosequencing of the non‐fixed specimens allowed the identification of mutations in the influenza virus surface glycoprotein (haemagglutinin gene) particularly at position 222.Results and ConclusionsThe overall course of illness lasted from 2 to 40 days (median 9 days). Diffused alveolar damage (DAD) was evident in 11 cases, 4 of which had no apparent underlying illness. Obesity was prominent in 12 cases, where three individuals were classified as otherwise healthy. The HA D222G mutation was detected in six cases, 3 of which had no underlying illness. Immunohistochemistry showed the A(H1N1)pdm09 virus to be prominent at the site of inflammation both in close proximity to and inside alveolar structures in the lung tissue. In addition to a possible role for the HA D222G mutation, our findings indicate that host factors and underlying conditions in the infected individuals are fundamental for disease outcome in many cases. This study increases our understanding of determinants for the clinical outcome of pandemic influenza, which could guide future treatment.

The 2009 H1N1 Pandemic Influenza in Korea.

In late March of 2009, an outbreak of influenza in Mexico, was eventually identified as H1N1 influenza A. In June 2009, the World Health Organization raised a pandemic alert to the highest level. More than 214 countries have reported confirmed cases of pandemic H1N1 influenza A. In Korea, the first case of pandemic influenza A/H1N1 infection was reported on May 2, 2009. Between May 2009 and August 2010, 750,000 cases of pandemic influenza A/H1N1 were confirmed by laboratory test. The H1N1-related death toll was estimated to reach 252 individuals. Almost one billion cases of influenza occurs globally every year, resulting in 300,000 to 500,000 deaths. Influenza vaccination induces virus-neutralizing antibodies, mainly against hemagglutinin, which provide protection from invading virus. New quadrivalent inactivated influenza vaccine generates similar immune responses against the three influenza strains contained in two types of trivalent vaccines and superior responses against the additional B strain.

Clinical Characteristics and Cost Burden of Children Hospitalized with Pandemic Influenza A (H1N1-2009) in a Tertiary Care Center in İstanbul.

Dear Editor, After the detection of the first case in April 2009, pandemic H1N1 influenza caused infection in more than 214 countries, resulting in at least 18,449 deaths. A multicenter study in Turkey revealed that 821 children were hospitalized with pandemic H1N1 influenza (1). The economic burden of pandemic H1N1 influenza has been estimated for many countries (2–4). We aimed to evaluate the clinical features and direct medical costs of children hospitalized with pandemic H1N1 influenza in comparison with H1N1 negative patients. Charts of children admitted to a single center with suspicion of pandemic H1N1 influenza were reviewed. Patients with clinical findings compatible with the criteria defined by the World Health Organization or a history of contact with a person with influenza-like illness (ILI) who had undergone microbiologic testing were included. The “in-house” real-time polymerase chain reaction protocol provided by the Centers for Disease Control and Prevention was used for the detection of pandemic H1N1 influenza. Underlying risk factors, clinical features, and total costs were determined. Total costs included bed stay, diagnostics, pharmacy, and charges for medical services. The present retrospective study was approved by the Institutional Ethics Committee and written informed consent was taken from all parents or legal guardians. Among 90 patients hospitalized during November 2009 and January 2010, 32 were laboratory confirmed cases of pandemic H1N1 influenza. 43.8% had an underlying risk factor, with neuromuscular disorders (18.8%) and chronic respiratory diseases (15.5%) being the most common. 31.2% had thrombocytopenia (platelets 11×103/mL), 37% had elevated aspartate amino-transferase (>35 IU/L) and 18% had elevated alanine aminotransferase levels (>46 IU/L). Fever (100% versus 84%) and lethargy (28.1% versus 8.6%) were more prevalent in H1N1 positive patients in comparison to H1N1 negative cases. Only one patient with pandemic H1N1 influenza and neuromuscular disease died on the 11th day of admission. The median cost of hospitalization for pandemic H1N1 influenza was $254 USD per case (Table 1). TABLE 1 Demographic, clinical and cost data of H1N1 positive and H1N1 negative patients Our study provides the first evidence that pandemic H1N1 influenza resulted in a substantial cost burden related to hospitalized children in Turkey. In comparison with H1N1 negative patients, the direct cost was slightly higher in the H1N1 positive group, but the difference was not significant since the majority of patients had received antiviral and antibiotic treatment due to heightened concern of physicians. The clinical features of the two groups were similar, except for a higher prevalence of fever and lethargy in the H1N1 positive patients. A similar study conducted in an adult population of Turkey revealed that altered mental status, fever ≥38°C, and tachypnea were significantly higher in patients with confirmed influenza (5). The mean hospital charges incurred for the 61 hospitalized children during the spring 2009 pandemic influenza epidemic in Wisconsin was $14,687 USD (2). Total direct health care costs were determined to be $510 USD per patient hospitalized with pandemic H1N1 influenza in Malaysia (3). Zarogoulidis et al. (4) reported that health care costs were higher for pandemic H1N1 influenza compared with non-H1N1 respiratory infections, mainly due to the protection measures used and the increased duration of hospitalization in the intensive care unit.

Pandemic Influenza (H1N1) andMycobacterium tuberculosisCo-infection

We hereby observe four co-infection cases of pandemic influenza H1N1 and Mycobacterium tuberculosis with various clinical presentations. It may be prudent to consider M. tuberculosis co-infections when patients with pandemic influenza reveal unusual clinical features that do not improve despite appropriate treatments against the influenza, especially in Korea, in the endemic areas of M. tuberculosis.

Antiviral role of toll-like receptors and cytokines against the new 2009 H1N1 virus infection

People are generally susceptible to the 2009 new mutate of H1N1 influenza due to lack of appropriate immunity. Influenza H1N1 2009 infection triggers a massive inflammatory response that contributes to fever, lung impairment or other tissue damage, eventually leading to death. Infection with pathogenic influenza virus H1N1 induces severe pulmonary immune pathology. To date, more than 10,000 cases worldwide have died of the disease. It still has strong infectious ability although the mortality of influenza isn't currently high. Therefore, to explore the pathogenesis of H1N1 influenza can help with the disease prevention, diagnosis and provide a theoretical basis and the new ideas of treatment. Laboratory confirmed cases of pandemic influenza H1N1 2009 were enrolled to collect general information on pre-clinical, clinical and laboratory data for analysis. Blood samples were obtained from patients with H1N1, healthy volunteers and patients with bacterial pneumonia. Serum were separated and collected. RT-PCR and ELISA methods were applied to detect the different expression of TLRs and cytokines. The young, pregnant and postpartum women and infant are highly susceptible to influenza H1N1 2009 infection; degree of susceptibility is not associated with BMI. Biochemical changes can be seen in the patients with influenza H1N1 2009 infection: ALT, AST, CK, LDH increased in varying degrees. TLR2, TLR3, TLR9 expression increased in the patients with influenza H1N1 2009 infection; no obvious changes of TLR4, TLR7, TLR8 can be detected. In pregnant and postpartum women group, only TLR9 expression increased. The expression of IL-2, IL-6, IFN-γ, TNF-α in the patients with influenza H1N1 2009 infection was significantly increased; while IL-10 expression decreased and IL-4 expression did not change. H1N1 influenza-infected pregnant and postpartum women group, only IL-2 and TNF-α expression expression increased, other cytokines decreased or didn't change. TLR2, TLR3, TLR9 are the major members of TLR family in the recognition of the novel H1N1 virus to start the innate immune response and adaptive immune responses. TLR9 may be the key receptor among pattern recognized receptors to recognize and bind to H1N1 virus. Cellular immune responses induced by Th1 may participate in modulating the influenza H1N1 2009.

Has estimation of numbers of cases of pandemic influenza H1N1 in England in 2009 provided a useful measure of the occurrence of disease?

Please cite this paper as: Evans et al. (2011) Has estimation of numbers of cases of pandemic influenza H1N1 in England in 2009 provided a useful measure of the occurrence of disease? Influenza and Other Respiratory Viruses 5(6), e504–e512. Background Surveillance indicators of influenza activity have generally provided robust comparative trend data for England. These indicators became less reliable, however, for monitoring trends in activity, or comparisons with previous years, during the influenza pandemic in 2009 because of changes in the perception of risk and changes in the systems of healthcare delivery. An approach was developed to estimate the number of cases of influenza‐like illness (ILI) occurring because of infection with pandemic influenza virus. Methods and findings The number of cases was estimated each week in England on the basis of total number of patients consulting healthcare services with ILI; estimates of the proportion of individuals in the community experiencing an ILI‐seeking health care; and the proportion of these positive on laboratory testing.Almost 800 000 cases (range 375 000–1·6 million) of symptomatic ILI cases were estimated to have occurred over the course of the two waves of pandemic activity in England. More cases were estimated to have occurred in the second wave than in the first. Conclusions These results underestimate the total number of infections as they do not include asymptomatic infections nor those with mild illness not meeting the definition of a case of ILI. Nevertheless, the case number estimates provide a useful indicator of the trend in influenza activity and weekly data were extensively used in media reports. Although surveillance methods differ between countries, the approach of synthesising available data sources to produce an overall estimate of case numbers could be applied more widely to provide comparative data.

Petechial Rash With Pandemic Influenza (H1N1) Infection

To the Editors: Acute fever and petechial rash in children pose a challenge for the pediatrician, because up to 20% of them will have serious bacterial infection.1 Influenza virus is not a common cause of rash, and a rare cause of petechial rash.1,2 Of 100 pediatric cases of pandemic influenza H1N1 admitted to our hospital from August until December 2009, we had 3 children, who presented in December 2009 with high fever, petechial rash, and rhinorrhea. All were treated for suspected meningococcal infection, but were proven to have novel influenza H1N1 by PCR, and negative blood cultures. They were discharged in a good clinical condition. The first child was an 18-month-old girl with high fever, cough, rhinorrhea, and loose stools. On admission she was well appearing and had a maculopapular rash over her chest with few petechial lesions. Because of her high fever and petechial rash (inspite of her well appearance), she was admitted and treated with ceftriaxone after blood cultures were taken. The next day a PCR for influenza H1N1 was positive, and after 2 days she was discharged with no additional treatment in a good medical condition. The other 2 children were about the same age and had similar histories and examinations. One of them was ill appearing, and both received antibiotics and antiviral therapy; they were well after few days. All 3 of them had normal platelet count, and all had positive PCR for H1N1 and blood cultures were sterile. The type of illness caused by influenza A virus infection depends on the age of the host. Most children younger than 5 years of age have fever and signs of upper respiratory tract involvement. Older children and adults have fever, chills, headache, sore throat, myalgia anorexia, and dry cough.2 Rash is not a common manifestation of influenza and petechial rash, simulating meningococcal infection, is rare.1,2 There are some reports of novel influenza H1N1, presented with rash,3–5 but it was uncommon, and there was no description of the rash in those articles, except for one case with a maculopapular rash.3 Children often present in the summer and fall with fever and petechial rash associated with enteroviral infection, but in other seasons it is not very common, raising the possibility of serious bacterial infection. Our 3 cases, in face of the current pandemic, illustrate the need to search for other viral and possible bacterial infections in a child with fever and petechial rash. Yael Shachor-Meyouhas, MD Imad Kassis, MD Pediatric Infectious Diseases Unit Meyer Children's Hospital Rambam Health Care Campus Haifa, Israel

Clinical features, treatments and prognosis of the initial cases of pandemic influenza H1N1 2009 virus infection in Shanghai China

As of 13 December 2009, more than 208 countries and overseas territories or communities have reported laboratory-confirmed cases of pandemic influenza H1N1 2009, which have resulted in at least 10 582 deaths. As of 7 December 2009, 4328 severe cases were reported in Mainland China, resulting in 326 deaths. This study's objective was to determine the clinical features, treatments and prognosis of the initial cases of Pandemic influenza H1N1 2009 virus infection in Shanghai, China, and how its clinical features related to patient gender. A total of 224 confirmed 2009 influenza A/H1N1-infected patients treated and discharged by Shanghai Public Health Clinical center between 24 May and 20 July 2009 were included in the study. Patients' personal information, signs and symptoms, laboratory and imagery data, disease course, hospitalization period and seroconversion duration for viral nucleic acid after antiviral treatment were analyzed. Among the 224 patients, 118 were male and 106 were female, yielding a sex ratio of 1.1:1. Approximately 52% of the patients came from Australia, and 63.8% were between 18 and 40 years old. Clinical manifestations included fever, cough and congestion of the throat, and lab findings were characterized by elevated C-reaction protein (CRP) and neutrophils. Female patients had significantly lower serum Prealbumin (PA) levels than male patients (P < 0.05). The patients' serum CRF levels significantly decreased after treatment (P < 0.05), while the levels of CD3, CD4 and CD8 significantly increased after treatment (P < 0.01). Approximately 29.9% of the patients had abnormal signs on chest computer tomography scan, and 21.9% had obvious signs indicating pneumonia. However, blood cultures were negative in these patients. The average disease course was 3.9 +/- 1.4 days, the average hospitalization period was 5.0 +/- 1.7 days, and the seroconversion duration for viral nucleic acid after antiviral treatment was 3.8 +/- 1.3 days. Initial cases of pandemic influenza H1N1 2009 were characterized by fever, cough and throat congestion, with elevated CRP and neutrophils being the most significant lab findings. The pandemic influenza H1N1 2009 strain was able to affect multiple organs, including the hepatic synthesis of PA and immune functioning. The novel 2009 Influenza A/H1N1 virus was mild clinically, with a short disease course and good prognosis.

Correlates of severe disease in patients with 2009 pandemic influenza (H1N1) virus infection

In the context of 2009 pandemic influenza (H1N1) virus infection (pandemic H1N1 influenza), identifying correlates of the severity of disease is critical to guiding the implementation of antiviral strategies, prioritization of vaccination efforts and planning of health infrastructure. The objective of this study was to identify factors correlated with severity of disease in confirmed cases of pandemic H1N1 influenza. This cumulative case-control study included all laboratory-confirmed cases of pandemic H1N1 influenza among residents of the province of Manitoba, Canada, for whom the final location of treatment was known. Severe cases were defined by admission to a provincial intensive care unit (ICU). Factors associated with severe disease necessitating admission to the ICU were determined by comparing ICU cases with two control groups: patients who were admitted to hospital but not to an ICU and those who remained in the community. As of Sept. 5, 2009, there had been 795 confirmed cases of pandemic H1N1 influenza in Manitoba for which the final treatment location could be determined. The mean age of individuals with laboratory-confirmed infection was 25.3 (standard deviation 18.8) years. More than half of the patients (417 or 52%) were female, and 215 (37%) of 588 confirmed infections for which ethnicity was known occurred in First Nations residents. The proportion of First Nations residents increased with increasing severity of disease (116 [28%] of 410 community cases, 74 [54%] of 136 admitted to hospital and 25 [60%] of 42 admitted to an ICU; p<0.001), as did the presence of an underlying comorbidity (201 [35%] of 569 community cases, 103 [57%] of 181 admitted to hospital and 34 [76%] of 45 admitted to an ICU; p<0.001). The median interval from onset of symptoms to initiation of antiviral therapy was 2 days (interquartile range, IQR 1-3) for community cases, 4 days (IQR 2-6) for patients admitted to hospital and 6 days (IQR 4-9) for those admitted to an ICU (p<0.001). In a multivariable logistic model, the interval from onset of symptoms to initiation of antiviral therapy (odds ratio [OR] 8.24, 95% confidence interval [CI] 2.82-24.1), First Nations ethnicity (OR 6.52, 95% CI 2.04-20.8) and presence of an underlying comorbidity (OR 3.19, 95% CI 1.07-9.52) were associated with increased odds of admission to the ICU (i.e., severe disease) relative to community cases. In an analysis of ICU cases compared with patients admitted to hospital, First Nations ethnicity (OR 3.23, 95% CI 1.04-10.1) was associated with increased severity of disease. Severe pandemic H1N1 influenza necessitating admission to the ICU was associated with a longer interval from onset of symptoms to treatment with antiviral therapy and with the presence of an underlying comorbidity. First Nations ethnicity appeared to be an independent determinant of severe infection. Despite these associations, the cause and outcomes of pandemic HINI influenza may involve many complex and interrelated factors, all of which require further research and analysis.

Estimated epidemiologic parameters and morbidity associated with pandemic H1N1 influenza

In the face of an influenza pandemic, accurate estimates of epidemiologic parameters are required to help guide decision-making. We sought to estimate epidemiologic parameters for pandemic H1N1 influenza using data from initial reports of laboratory-confirmed cases. We obtained data on laboratory-confirmed cases of pandemic H1N1 influenza reported in the province of Ontario, Canada, with dates of symptom onset between Apr. 13 and June 20, 2009. Incubation periods and duration of symptoms were estimated and fit to parametric distributions. We used competing-risk models to estimate risk of hospital admission and case-fatality rates. We used a Markov Chain Monte Carlo model to simulate disease transmission. The median incubation period was 4 days and the duration of symptoms was 7 days. Recovery was faster among patients less than 18 years old than among older patients (hazard ratio 1.23, 95% confidence interval 1.06-1.44). The risk of hospital admission was 4.5% (95% CI 3.8%-5.2%) and the case-fatality rate was 0.3% (95% CI 0.1%-0.5%). The risk of hospital admission was highest among patients less than 1 year old and those 65 years or older. Adults more than 50 years old comprised 7% of cases but accounted for 7 of 10 initial deaths (odds ratio 28.6, 95% confidence interval 7.3-111.2). From the simulation models, we estimated the following values (and 95% credible intervals): a mean basic reproductive number (R0, the number of new cases created by a single primary case in a susceptible population) of 1.31 (1.25-1.38), a mean latent period of 2.62 (2.28-3.12) days and a mean duration of infectiousness of 3.38 (2.06-4.69) days. From these values we estimated a serial interval (the average time from onset of infectiousness in a case to the onset of infectiousness in a person infected by that case) of 4-5 days. The low estimates for R0 indicate that effective mitigation strategies may reduce the final epidemic impact of pandemic H1N1 influenza.

Diagnosis of influenza viruses with special reference to novel H1N1 2009 influenza virus

On 15 April and 17 April 2009, novel swineorigin influenza A (H1N1) virus was identifi ed in specimens obtained from two epidemiologically unlinked patients in the United States. The ongoing outbreak of novel H1N1 2009 influenza (swine influenza) has caused more than 3,99,232 laboratory confi rmed cases of pandemic influenza H1N1 and over 4735 deaths globally. This novel 2009 influenza virus designated as H1N1 A/swine/California/04/2009 virus is not zoonotic swine flu and is transmitted from person to person and has higher transmissibility then that of seasonal influenza viruses. In India the novel H1N1 virus infection has been reported from all over the country. A total of 68,919 samples from clinically suspected persons have been tested for influenza A H1N1 across the country and 13,330 (18.9%) of them have been found positive with 427 deaths. At the All India Institute of Medical Sciences, New Delhi India, we tested 1096 clinical samples for the presence of novel H1N1 influenza virus and seasonal influenza viruses. Of these 1096 samples, 194 samples (17.7%) were positive for novel H1N1 influenza virus and 197 samples (18%) were positive for seasonal influenza viruses. During outbreaks of emerging infectious diseases accurate and rapid diagnosis is critical for minimizing further spread through timely implementation of appropriate vaccines and antiviral treatment. Since the symptoms of novel H1N1 influenza infection are not specifi c, laboratory confi rmation of suspected cases is of prime importance.

Surveillance of the first 205 confirmed hospitalised cases of pandemic H1N1 influenza in Ireland, 28 April – 3 October 2009

From 28 April 2009 to 3 October 2009, 205 cases of confirmed pandemic H1N1 influenza were hospitalised in Ireland. Detailed case-based epidemiological information was gathered on all hospitalised cases. Age-specific hospitalisation rates were highest in the age group of 15 to 19 year-olds and lowest in those aged 65 years and over. Nineteen hospitalised cases (9%) were admitted to intensive care units (ICU) where the median length of stay was 24 days. Four hospitalised cases (2%) died. Fifty-one percent of hospitalised cases and 42% of ICU cases were not in a recognised risk group. Asthma was the most common risk factor among cases; however, people with haemoglobinopathies and immunosuppression were the most over-represented groups.

Progression and impact of the first winter wave of the 2009 pandemic H1N1 influenza in New South Wales, Australia

A range of surveillance systems were used to assess the progression and impact of the first wave of pandemic H1N1 influenza in New South Wales, Australia during the southern hemisphere winter. Surveillance methods included laboratory notifications, near real-time emergency department syndromic surveillance, ambulance despatch surveillance, death certificate surveillance and purpose-built web-based data systems to capture influenza clinic and intensive care unit activity. The epidemic lasted 10 weeks. By 31 August 2009, 1,214 people with pandemic H1N1 influenza infection were hospitalised (17.2 per 100,000 population), 225 were admitted to intensive care (3.2 per 100,000), and 48 died (0.7 per 100,000). Children aged 0-4 years had the highest hospitalisation rates, while adults aged 50-54 had the highest rates of intensive care admission. During the epidemic period, overall presentations to emergency departments were 6% higher than in 2008, while presentations for influenza-like illness were 736% higher. At the peak, confirmed cases of pandemic H1N1 influenza consumed 15% of intensive care capacity. Excess mortality from influenza and pneumonia was lower than in recent influenza seasons. Health services, particularly emergency departments and intensive care units, were substantially affected by the epidemic. Mortality from influenza was comparable with previous seasons.

Pandemic H1N1 influenza in Brazil: Analysis of the first 34,506 notified cases of influenza-like illness with severe acute respiratory infection (SARI)

Recently, the brunt of the current influenza pandemic has been felt in the southern hemisphere. We report an analysis of the first 34,506 cases of influenza-like illness with severe acute respiratory infection (SARI) notified in Brazil during the epidemiological weeks 16 to 33. The 5,747 confirmed cases of pandemic H1N1 influenza showed two incidence peaks across the age span: one in children up to the age of five years (3.8/100,000) and one in individuals aged 20 to 29 years (4.6/100,000). People over the age of 60 had the lowest incidence (1.1/100,000 inhabitants). The epidemic peaked rapidly. Ninety-four percent of cases were concentrated in two of Brazil s five geographic regions - the south and southeast, regions that have a more temperate climate and thus colder winters. Case-fatality of pandemic influenza presenting with SARI was 11.2% (95% confidence interval (CI): 10.4%-12.1%). People with a reported comorbidity had approximately twice the risk of those without (relative risk=1.89; 95%CI: 1.64-2.18).

Detection of influenza A(H1N1)v virus by real-time RT-PCR

Influenza A(H1N1)v virus was first identified in April 2009. A novel real-time RT-PCR for influenza A(H1N1)v virus was set up ad hoc and validated following industry-standard criteria. The lower limit of detection of the assay was 384 copies of viral RNA per ml of viral transport medium (95% confidence interval: 273-876 RNA copies/ml). Specificity was 100% as assessed on a panel of reference samples including seasonal human influenza A virus H1N1 and H3N2, highly pathogenic avian influenza A virus H5N1 and porcine influenza A virus H1N1, H1N2 and H3N2 samples. The real-time RT-PCR assay for the influenza A matrix gene recommended in 2007 by the World Health Organization was modified to work under the same reaction conditions as the influenza A(H1N1)v virus-specific test. Both assays were equally sensitive. Clinical applicability of both assays was demonstrated by screening of almost 2,000 suspected influenza (H1N1)v specimens, which included samples from the first cases of pandemic H1N1 influenza imported to Germany. Measuring influenza A(H1N1)v virus concentrations in 144 laboratory-confirmed samples yielded a median of 4.6 log RNA copies/ml. The new methodology proved its principle and might assist public health laboratories in the upcoming influenza pandemic.

H1N1 (Pandemic) 2009 Influenza : Our Action Plan for Future

DOI: 10.3329/bmj.v39i1.6224Bangladesh Medical Journal 2010; 39(1): 1-2