2009甲型H1N1流感大流行期间北京儿童的流感监测

目的 了解2009年甲型H1N1流感大流行期间北京地区儿童中流感流行的情况.方法 采用WHO推荐的实时荧光定量RT-PCR和国家流感中心推荐的分型方法,对2009年甲型H1N1流感大流行期间因流感样症状来首都儿科研究所附属儿童医院就诊患儿的咽拭子标本进行流感病毒核酸检测.结果 2009年6月1日至2010年2月28日期间共检测了4363份咽拭子标本,其中623例为甲型H1N1阳性,阳性率为14.3%,657例为其他甲型流感病毒阳性(15.1%),所有甲型流感病毒的总阳性率为29.3%.623例中有23例为危重症病例(占阳性患者的3.7%),其中5例死亡.618例信息完整的甲型H1N1病例中,患儿年龄为14天～16岁,性别比例为男比女为1.3:1.1～3岁儿童占25.2%,3～6岁学龄前儿童和6～12岁学龄儿童所占比例相近,各约占30%.在监测期间,仅呈现了一个甲型H1N1的流行波.2009年11月达到最高峰,随后减弱,2010年2月快速下降至2.7%.对监测期间每周20～30份临床标本同时进行季节性流感的监测显示,季节性H3N2、甲型H1N1和乙型流感交替流行.呼吸道合胞病毒(RSV)在甲型H1N1流行趋势减缓后逐渐流行成为流行优势株.结论 2009年6月至2010年2月北京地区儿童中出现甲型H1N1的流行,主要累及学龄前和学龄儿童.季节性流感和RSV与甲型H1N1交替流行.     

A comparison of H1N1 influenza among pediatric inpatients in the pandemic and post pandemic era

BackgroundThe novel influenza A H1N1 (A[H1N1]pdm09) strain emerged in 2009, contributing to significant morbidity and mortality. It is not known whether illness associated with A(H1N1) pdm09 in the post-pandemic era exhibits a similar disease profile.ObjectiveThe objectives of this study were to compare the burden of disease of A(H1N1) pdm09 influenza from the 2009 pandemic year to the post-pandemic years (2010–2014), and to explore potential reasons for any differences.Study designWe conducted a retrospective cohort study of inpatients admitted to Children’s Hospital Colorado with a positive respiratory specimen for influenza from May–December, 2009 and December, 2010–April, 2014. Univariate and multivariate analyses were conducted to compare the demographics and clinical characteristics of patients with H1N1 during the two periods.ResultsThere were 388 inpatients with influenza A(H1N1) pdm09 in 2009, and 117 during the post-pandemic years. Ninety-four percent of all H1N1 during the post-pandemic era was observed during the 2013–2014 influenza season. Patients with A(H1N1) pdm09 during the post-pandemic year were less likely to have an underlying medical condition (P < 0.01). Patients admitted to the ICU during the post-pandemic year had a lower median age (5 vs 8 years, P = 0.01) and a lower proportion of patients were intubated, had mental status changes, and ARDS compared with the pandemic years, (P < 0.01 for all), with decreased mortality (P = 0.02).ConclusionPatients with influenza A(H1N1) pdm09 during the post-pandemic years appeared to have less severe disease than patients with A(H1N1) pdm09 during the pandemic year. The reasons for this difference are likely multifactorial.     

Molecular characterization of the influenza A(H1N1)pdm09 isolates collected in the 2015-2016 season and comparison of HA mutations detected in Turkey since 2009

Influenza A(H1N1)pdm09 pandemic virus causing the 2009 global outbreak moved into the post-pandemic period, but its variants continued to be the prevailing subtype in the 2015-2016 influenza season in Europe and Asia. To determine the molecular characteristics of influenza A(H1N1)pdm09 isolates circulating during the 2015-2016 season in Turkey, we identified mutations in the hemagglutinin (HA) genes and investigated the presence of H275Y alteration in the neuraminidase genes in the randomly selected isolates. The comparison of the HA nucleotide sequences revealed a very high homology (>99.5%) among the studied influenza A(H1N1)pdm09 isolates, while a relatively low homology (96.6%-97.2%), was observed between Turkish isolates and the A/California/07/2009 vaccine virus. Overall 14 common mutations were detected in HA sequences of all 2015-2016 influenza A(H1N1)pdm09 isolates with respect to the A/California/07/2009 virus, four of which located in three different antigenic sites. Eleven rare mutations in 12 HA sequences were also detected. Phylogenetic analysis revealed that all characterized influenza A(H1N1)pdm09 isolates formed a single genetic cluster, belonging to the genetic subclade 6B.1, defined by HA amino acid substitutions S84N, S162N, and I216T. Furthermore, all isolates showed an oseltamivir-sensitive genotype, suggesting that Tamiflu (Oseltamivir) could still be the drug of choice in Turkey.     

Identification of oseltamivir resistance among pandemic and seasonal influenza A (H1N1) viruses by an His275Tyr genotyping assay using the cycling probe method

Neuraminidase inhibitors are agents used against influenza viruses; however, the emergence of drug-resistant strains is a major concern. Recently, the prevalence of oseltamivir-resistant seasonal influenza A (H1N1) virus increased globally and the emergence of oseltamivir-resistant pandemic influenza A (H1N1) 2009 viruses was reported. In this study, we developed a cycling probe real-time PCR method for the detection of oseltamivir-resistant seasonal influenza A (H1N1) and pandemic influenza A (H1N1) 2009 viruses. We designed two sets of primers and probes that were labeled with 6-carboxyfluorescein or 6-carboxy-X-rhodamine to identify single nucleotide polymorphisms (SNPs) that correspond to a histidine and a tyrosine at position 275 in the neuraminidase protein, respectively. These SNPs confer susceptibility and resistance to oseltamivir, respectively. In the 2007-2008 season, the prevalence of oseltamivir-resistant H1N1 viruses was 0% (0/72), but in the 2008-2009 season, it increased to 100% (282/282). In the 2009-2010 season, all of the pandemic influenza A (H1N1) 2009 viruses were susceptible to oseltamivir (0/73, 0%). This method is sensitive and specific for the screening of oseltamivir-resistant influenza A (H1N1) viruses. This method is applicable to routine laboratory-based monitoring of drug resistance and patient management during antiviral therapy.     

Duration of viral shedding in patients admitted to hospital with pandemic influenza A/H1N1 2009 infection

Little is known about the kinetics of viral shedding of pandemic influenza A/H1N1 2009 virus. Influenza RNA, as a surrogate for viral clearance, was therefore measured on days 1, 5, 7, and 10 or more in patients admitted to hospital with pandemic influenza A/H1N1 2009 infection. A total of 72 patients who were admitted to hospital with confirmed pandemic influenza A/H1N1 2009 at a tertiary care hospital, Seoul, South Korea, between 1 September and 11 November 2009 were evaluated. The median duration of viral shedding, as assessed by RT-PCR, was 9 days, as determined by the Kaplan-Meier method. Patients who were positive by RT-PCR at their last assay, but who were discharged before the next RT-PCR test due to symptom improvement, were censored from the analysis. If such patients were included, with the assumption that they had negative viral status at discharge, the median duration of viral shedding was 5 days (interquartile range, 2-8 days). These calculations thus suggest that the true median duration of viral shedding is between 5 and 9 days. Univariate analysis showed that delayed administration of antiviral therapy and comorbidity were associated with slower viral clearance. Multivariate analysis showed that oseltamivir started after the first day of symptoms (OR 2.7, 95% CI 1.2-5.7) was associated independently with slower viral clearance. These findings indicate that, in about 50% of patients admitted to hospital with pandemic influenza A/H1N1 2009, virus can be positive as tested by RT-PCR on the eighth day after developing symptoms of influenza. The present findings also indicate that starting antiviral therapy within 24 hr of the onset of symptoms is associated with more rapid viral clearance.     

Pre- and post-pandemic prevalence of antibodies to the 2009 pandemic influenza A (H1N1) virus in Austrian adults

Antibody prevalence to the 2009 pandemic influenza A (H1N1) virus was determined in a sample of the Austrian population to assess the post-pandemic seropositivity rate, the infection attack rate, and the proportion of subclinical infections during the 2009/2010 influenza pandemic in Austrian adults. A total of 480 sera from individuals aged between 18 and 57 years from all nine federal states of Austria were collected between April and June 2010. Information on demographic characteristics, vaccination history, and history of suspected or verified influenza virus infection was ascertained. Antibodies were determined using a commercial ELISA and compared with 80 age-matched adult sera collected before the pandemic began. The overall seropositivity rate was 28% and was highest among young adults aged 18-29 years, followed by adults aged 50-57 years. Among seropositive unvaccinated individuals, infection was asymptomatic in more than 80%. Extrapolation to the overall Austrian adult population indicates that more than 1.3 million persons aged 18-57 years became infected in 2009. Compared with the pre-pandemic seropositivity rate, the infection rate was highest among young adults but low in those aged 30-57 years. Among 69 individuals previously vaccinated with the 2009 pandemic influenza A (H1N1) virus, 71% had specific antibodies. The study demonstrates that infection rates based on surveillance of clinical cases considerably underestimated the infection attack rate during the 2009 H1N1 pandemic in Austria and that vaccination against this virus elicited long-lasting seropositivity in more than 70% of adults.     

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.     

Antiviral drug susceptibilities of seasonal human influenza viruses in Lebanon, 2008–09 season

The emergence of antiviral drug‐resistant strains of the influenza virus in addition to the rapid spread of the recent pandemic A(H1N1) 2009 virus highlight the importance of surveillance of influenza in identifying new variants as they appear. In this study, genetic characteristics and antiviral susceptibility patterns of influenza samples collected in Lebanon during the 2008–09 season were investigated. Forty influenza virus samples were isolated from 89 nasopharyngeal swabs obtained from patients with influenza‐like illness. Of these samples, 33 (82.5%) were A(H3N2), 3 (7.5%) were A(H1N1), and 4 (10%) were B. All the H3N2 viruses were resistant to amantadine but were sensitive to oseltamivir and zanamivir; while all the H1N1 viruses were resistant to oseltamivir (possessed H275Y mutation, N1 numbering, in their NA) but were sensitive to amantadine and zanamivir. In the case of influenza B, both Victoria and Yamagata lineages were identified (three and one isolates each, respectively) and they showed decreased susceptibility to oseltamivir and zanamivir when compared to influenza A viruses. Influenza circulation patterns in Lebanon were very similar to those in Europe during the same season. Continued surveillance is important to fully elucidate influenza patterns in Lebanon and the Middle East in general, especially in light of the current influenza pandemic. J. Med. Virol. 82: 1224–1228, 2010. © 2010 Wiley‐Liss, Inc.     

Dynamics of clinical symptoms in patients with pandemic influenza A (H1N1)

We evaluated the dynamics of clinical symptoms of 2009 pandemic influenza A (H1N1) using a four-point scale sheet. The most frequent symptoms were fever and cough. The sum of symptom score was high during the first 4 days. Systemic symptoms peaked earlier, by day 2, and resolved faster than upper respiratory symptoms and lower respiratory symptoms after oseltamivir treatment. The lower respiratory symptoms resolved slowly over 2 weeks. The 2009 pandemic influenza A (H1N1) virus might involve primarily lower respiratory tract and could be the main cause of pneumonia.     

Lymphocytopenia as a marker for pandemic influenza A/H1N1 2009 virus infection in children

Lymphocytopenia has been reported in adults with pandemic influenza A/H1N1 2009 infection, but data in children are inconclusive. Data from 76 children presented with flu‐like symptoms between July and November 2009 and tested for pandemic influenza A/H1N1 2009 virus and white blood cell (WBC) counts were analyzed. Samples from 37 (48.7%) children resulted in a positive PCR assay for pandemic influenza A/H1N1 2009 virus. When comparing data from these children with data from 39 (51.3%) children with uncomplicated flu‐like illness and negative PCR assay for pandemic influenza A/H1N1 2009 virus, no difference in disease duration, median age, red blood cell count, hemoglobin concentration, C reactive protein concentration, and absolute neutrophil count was observed, whereas significant differences were apparent when considering WBC count, relative and absolute lymphocyte count, absolute lymphocyte count z‐score, and platelet count. Receiver operating characteristic curve analysis revealed that the best absolute lymphocyte count and absolute lymphocyte count z‐score cut‐points that simultaneously maximized sensitivity and specificity were 2,256 cells/µl and ?0.89, respectively, sensitivity being 0.81 (95% CI: 0.68–0.94), specificity 0.87 (95% CI: 0.77–0.98), positive predictive value 0.85 (95% CI: 0.74–0.97), and negative predictive value 0.83 (95% CI: 0.71–0.94). In conclusion, lymphocytopenia is a marker for influenza A/H1N1 2009 virus infection in children. Absolute lymphocyte count <2,556 cells/µl or absolute lymphocyte count z‐score < ?0.89 may be useful cut‐offs to discriminate against children at higher risk of infection during epidemics. Considering that the pandemic virus is highly likely to continue to circulate in the coming winter season, these findings provide direct and practical implications for the near future. J. Med. Virol. 83:1–4, 2011. © 2010 Wiley‐Liss, Inc.     

First influenza season after the 2009 pandemic influenza: characteristics of intensive care unit admissions in adults and children in Vall d'Hebron Hospital

To assess potential differences in epidemiology and management of patients admitted with influenza infection in the intensive care unit (ICU) during the first post-pandemic influenza period. Observational prospective study comparing September 2009–January 2010 with September 2010–January 2011. Variables captured: demographics, co-morbidities, physiological parameters, outcomes and management. Analysis was performed using SPSS v. 13.0; significance was set at p 0.5. Data from 53 patients, 38 adults (age, median 41.5 years; interquartile range (IQR) 32.8–51.3) and 15 children (age, median 2 years, IQR 0.5–9) are presented. Vaccination rates were 0% and 4.3% during the first and second periods, respectively. Differences postpandemic were: 100% of episodes developed after December compared with 16.7% in the 2009 season. Younger children were affected (median age 0.8 years (IQR 0.3–4.8) vs 7 years (IQR 1.25–11.5), p 0.05) and influenza B caused 8.7% of ICU admissions. Influenza A (H1N1) 2009 and respiratory syncytial virus epidemics occurred simultaneously (42.8% of children) and bacterial co-infections doubled (from 10% to 21.7%); the prevalence of co-infections (viral or bacterial) increased from 10% to 39.1% (OR 5.8, 95% CI 1.3–24.8). Respiratory syndromes without chest X-ray opacities reflecting exacerbation of asthma or chronic obstructive pulmonary disease, bronchitis or bronchiolitis increased (from 6.9% to 39.1%, p <0.05) and pneumonia decreased (from 83.3% to 56.5%, p <0.05). Primary viral pneumonia predominated among ICU admissions. Postpandemic ICU influenza developed later, with some cases of influenza B, more frequent bacterial and viral co-infections and more patients with severe acute respiratory infection with normal chest X-ray. Increasing vaccination rates among risk-group individuals is warranted to prevent ICU admission and death.     

Serological study of the 2009 pandemic due to influenza A H1N1 in the metropolitan French population

We looked for evidence of antibodies to the 2009 influenza A/H1N1 pandemic virus in panels of sera from individuals living in metropolitan France, obtained either before, during or after the epidemic, using standard haemagglutination inhibition and microneutralization tests. The difference between seroprevalence values measured in post- and pre-epidemic panels was used as an estimate of seroconversion rate in different age groups (23.4% (0–24 years, age-group 0); 16.5% (25–34); 7.9% (35–44); 7.2% (45–54); 1.6% (55–64); and 3.1% (<65)), confirming that the distribution of cases in different age groups was similar to that of the seasonal H1N1 virus. During the pre-pandemic period low-titre cross-reactive antibodies were present in a large proportion of the population (presumably acquired against seasonal H1N1) whereas cross-reactive antibodies were detected in individuals over the age of 65 years with significantly higher prevalence and serological titres (presumably acquired previously against Spanish flu-related H1N1 strains). Clinical data and analysis of post-pandemic seroprevalence showed that few of these latter patients were infected by the influenza virus during the epidemic. In contrast, the majority of both clinical cases and seroconversions were recorded in the 0–24 age group and a global inverse relationship between prevalence of antibodies to pH1N1 in the pre-pandemic period and rate of seroconversion was observed amongst age groups. Our results emphasize the complex relationships involved in antigenic reactivity to pandemic and seasonal H1N1 viral antigens; hence the difficulty in distinguishing between low-titre specific and cross-reactive antibodies, establishing precise seroprevalence numbers and fully understanding the relationship between previous immunity to seasonal viruses and protection against the novel variant.     

广东省深圳市流感流行特征分析

目的 掌握深圳市流感流行规律,了解甲流大流行以后流感的流行趋势.方法 对深圳市流感样病例监测数据、病原学检测结果和暴发疫情资料进行分析.结果 深圳市的流感样病例百分比(ILI％)为4.67％,呈逐年下降趋势,ILI年龄构成以0-4岁为主(占54.2％).流感病毒分离平均阳性率为10.6％,按月分析流感病毒分离阳性率与ILI％变化趋势呈正相关(r=0.447,P =0.001).全市报告了482起ILI暴发疫情,以乙型流感为主(占63.9％).2010年深圳市季节性流感出现了春季和夏季流行高峰,分别以乙型Victoria系和甲型H1N1亚型为优势株;2011年为冬春季和秋季高峰,以甲型H1N1和季节性H3亚型为优势株;2012年出现了冬春季和夏季高峰,以乙型(Victoria系和Yamagata系)和季节性H3亚型为优势株;2013年出现了春、秋、冬季三个流行高峰,分别以甲型H1N1、季节性H3和乙型Yamagata系为优势株.结论 深圳市季节性流感每年均出现2-3个流行高峰,分别在冬春季和夏秋季,每年流行高峰出现的时间不同,每年流行的型别不同.     

2009 H1N1 influenza infection in Korean healthcare personnel

Healthcare personnel (HCP) can acquire influenza and transmit it to patients and other hospital staff. The aim of this study was to evaluate the attack rate of HCP by the 2009 H1N1 influenza virus during the 2009 pandemic influenza season in Korea. HCP infected with H1N1 virus were asked to fill out a questionnaire, which included job type, method of diagnosis, facility type, history of contact with patients infected by H1N1 virus, vaccination status, and use of personal protective equipment. A total of 328 HCP (female 68.6%, 225/328) were infected with H1N1 virus at the nine study centers. The highest attack rate was in physicians, followed by nurses and nurses’ aides. Transmission occurred primarily after contact with outpatients (27.8%), followed by contact with inpatients (21.6%). Most (77.3%) of the infected HCP never used an N95 mask during contact with patients. Surgical masks were always used by 29.4% of the subjects and usually or intermittent used by 46.9%. The peak incidence of the H1N1 infection among HCP preceded that among the general population. Among HCPs, physicians, nurses, and nurses’ aides were at the greatest risk of H1N1 infection. HCP should be more vigilant and protect themselves with appropriate personal protective equipment during the influenza season.     

Pandemic influenza A (H1N1) 2009 vaccine: an update

The world witnessed a the first influenza pandemic in this century and fourth overall since first flu pandemic was reported during the World War I. The past experiences with influenza viruses and this pandemic of H1N1 place a consider-able strain on health services and resulted in serious illnesses and a large number of deaths. Develop-ing countries were declared more likely to be at risk from the pandemic effects, as they faced the dual problem of highly vulnerable populations and limited resources to respond H1N1. The public health experts agreed that vaccination is the most effective ways to mitigate the negative effects of the pandemic. The vaccines for H1N1 virus have been used in over 40 countries and administered to over 200 million people helped in a great way and on August 10, 2010, World Health Organization (WHO) announced H1N1 to be in postpandemic period. But based on knowledge about past pandemics, the H1N1 (2009) virus is expected to continue to circulate as a seasonal virus and may undergo some agenic-variation. As WHO strongly recommends vaccination, vigilance for regular updating of the composition of influenza vaccines, based on an assessment of the future impact of circulating viruses along with safety surveillance of the vaccines is necessary. This review has been done to take a stock of the currently available H1N1 vaccines and their possible use as public health intervention in the postpandemic period.     

Pathologic study of pandemic influenza A (H1N1) 2009 cases from India

The pandemic influenza A (H1N1) 2009 originated in Mexico and rapidly spread to the United States and many other countries. India reported the first pandemic influenza case in May 2009. Autopsy studies describing the pathology of pandemic influenza infection in humans have appeared in the literature and most of these were from Western countries. We present the clinicopathologic features in 46 fatal cases with confirmed pandemic influenza A (H1N1) 2009 virus infection during August 2009 to October 2010. Postmortem needle biopsy tissues were examined for histopathological changes and distribution of virus antigen by immunohistochemistry. The results are comparable with previous autopsy studies. Diffuse alveolar damage was the consistent finding in the lung tissues. However, underlying medical conditions were not noted in the cases from present study. Consistent presence of viral antigen was noted in the bronchiolar epithelium without any reference to the duration of illness. This study also emphasizes the use of the postmortem needle biopsy technique whenever an autopsy is not possible.     

Pandemic influenza A(H1N1) virus infection in solid organ transplant recipients: impact of viral and non-viral co-infection

Solid organ transplant recipients (SOTR) are at risk of serious influenza-related complications. The impact of respiratory co-infection in SOTR with 2009 pandemic influenza A(H1N1) is unknown. A multicentre prospective study of consecutive cases of pandemic influenza A(H1N1) in SOTR was carried out to assess the clinical characteristics and outcome and the risk factors for co-infection. Overall, 51 patients were included. Median time from transplant was 3.7 years, 5.9% of the cases occurred perioperatively and 7.8% were hospitalacquired. Pneumonia was diagnosed in 15 (29.4%) patients. Ten cases were severe (19.6%): 13.7% were admitted to intensive care units, 5.9% suffered septic shock, 5.9% developed acute graft rejection and 7.8% died. Co-infection was detected in 15 patients (29.4%): eight viral, six bacterial and one fungal. Viral co-infection did not affect the outcome. Patients with non-viral co-infection had a worse outcome: longer hospital stay (26.2 ± 20.7 vs. 5.5 ± 10.2) and higher rate of severe diseases (85.7% vs. 2.3%) and mortality (42.8% vs. 2.3%). Independent risk factors for non-viral co-infection were: diabetes mellitus and septic shock. Other factors associated with severe influenza were: delayed antiviral therapy, diabetes mellitus, time since transplantation <90 days and pneumonia. In conclusion, pandemic influenza A can cause significant direct and indirect effects in SOTR, especially in the early post-transplant period, and should be treated early. Clinicians should be aware of the possibility of non-viral co-infection, mainly in diabetic patients and severe cases. An effort should be made to prevent influenza with immunization of the patient and the environment.     

Influenza virus A(H1N1)pdm09 hemagglutinin polymorphism and associated disease in southern Germany during the 2010/11 influenza season

A novel influenza A virus emerged in early 2009 to cause the first influenza pandemic of the 21^st century. Understanding the evolution of influenza virus is crucial to determine pathogenesis, vaccine efficacy, and resistance to antiviral drugs. In this study, we investigated the molecular evolution of influenza virus A(H1N1)pdm09 in the 2010/11 influenza season in southern Germany by sequence analysis of the influenza virus hemagglutinin gene from 25 patients with mild, moderate, and severe disease. Phylogenetic analysis revealed co-circulation of different genetic groups. The D222G mutation, which had previously been observed in severe cases, was not detected. Immunocompromised patients were not affected more severely than non-immunocompromised patients (p>0.05), although longer shedding was observed in some of them. Interestingly, additional mutations and potential glycosylation sites were detected in samples from the lower respiratory tract in two patients, but not in the corresponding upper respiratory tract specimens. The H275Y mutation in the influenza virus neuraminidase gene, known to confer resistance to the neuraminidase inhibitor oseltamivir, was detected in one patient.