Experimental pandemic (H1N1) 2009 virus infection of cats

To demonstrate that pandemic (H1N1) 2009 virus may cause respiratory disease in cats, we intratracheally infected cats. Diffuse alveolar damage developed. Seroconversion of sentinel cats indicated cat-to-cat virus transmission. Unlike in cats infected with highly pathogenic avian influenza virus (H5N1), extrarespiratory lesions did not develop in cats infected with pandemic (H1N1) 2009 virus.     

Pandemic (H1N1) 2009 encephalitis in woman, Taiwan

We report an unusual case of pandemic (H1N1) 2009-related encephalitis in an immunocompetent woman. Although rare cases of pandemic (H1N1) 2009 associated with encephalitis have been reported previously, in this patient, direct viral invasion of the central nervous system was shown by simultaneous detection of viral RNA and pleocytosis.     

江苏省2009年3岁以上自然人群新甲型H1N1流感血清流行病学调查

目的 了解江苏省2009年3岁以上自然人群新甲型H1N1流感抗体水平及流行趋势.方法 利用微量半加敏血凝抑制(HI)方法检测江苏省不同时间(2008年11月和2009年7、8、11月)人群新甲型H1N1流感抗体,比较不同时间、人群及地区的新甲型H1N1流感保护性抗体阳性率和抗体几何平均滴度(GMTs).结果 在新甲型H1N1流感输入江苏地区后第一个流行季节内,2009年7、8、11月人群HI保护性抗体阳性率依次为3.46%、7.59%和16.94%,表现出随时间推移而呈总体增长趋势(P=0.000),不同时间点的性别间保护性抗体阳性率的差异无统计学意义(P＞0.05);除2009年11月外,不同性别间的抗体GMT差异均无统计学意义.同一时间点不同年龄组间、同一年龄组的不同时间点间,HI保护性抗体阳性率、抗体GMT水平比较的差异均有统计学意义(P＜0.05).HI保护性抗体阳性率和抗体GMT存在地区差异(P＜0.05).结论 在2009年8月后江苏地区12～17岁人群成为新甲型H1N1流感暴发的主要人群,至2009年11月该人群总体新甲型H1N1流感保护性抗体阳性率仍较低,该病在全省的流行仍将持续一段时间.     

Household transmission of Pandemic (H1N1) 2009 Virus, Taiwan

During August-November 2009, to investigate disease transmission within households in Taiwan, we recruited 87 pandemic (H1N1) 2009 patients and their household members. Overall, pandemic (H1N1) 2009 virus was transmitted to 60 (27%) of 223 household contacts. Transmission was 4× higher to children than to adults (61% vs. 15%; p<0.001).     

Drug-resistant pandemic (H1N1) 2009, South Korea

Eleven patients with drug-resistant pandemic (H1N1) 2009 were identified in South Korea during May 2009-January 2010. Virus isolates from all patients had the H275Y mutation in the neuraminidase gene. One isolate had the I117M mutation. Of the 11 patients, 6 were ≥ 59 months of age, and 5 had underlying immunosuppressive conditions.     

Pandemic (H1N1) 2009, Shanghai, China

To understand the clinical and epidemiologic characteristics of pandemic (H1N1) 2009 virus infection, we retrospectively reviewed medical records of 237 patients with laboratory-confirmed cases reported in Shanghai, China, during May–July 2009. Surveillance activities effectively contained the outbreak and provided useful epidemiologic data for future strategies.     

Serologic survey of pandemic influenza A (H1N1 2009) in Beijing, China

Objective

To examine the frequency and distribution of antibodies against pandemic influenza A (H1N1 2009) [H1N1] in populations in Beijing and elucidate influencing factors.

Methods

In January 2010, a randomized serologic survey of pandemic influenza A (H1N1 2009) was carried out. Six districts that were randomly selected with a total of 4601 participants involved in the survey have their antibody level tested by hemagglutination inhibition assay.

Results

Among the 4601 participants, the overall seropositive rate for pandemic influenza A (H1N1 2009) antibodies was 31.7%. The seropositivity prevalence in participants who received the pandemic H1N1 vaccination was 60.9%. Only 53.1% of the pandemic influenza A (H1N1 2009) seropositive individuals who had not received the vaccination experienced respiratory tract infection symptoms. Multivariate logistic regression revealed that factors such as age, occupation, dwelling type, whether the participant's family included students in school, and the vaccination history with pandemic influenza A (H1N1 2009) were associated with antibody titers (p < 0.05).

Conclusions

Our data indicated that almost 30.0% of the residents had appropriate antibody titers against pandemic influenza A (H1N1 2009) in Beijing, and these titers may provide an immune barrier.     

Ultrastructural characterization of pandemic (H1N1) 2009 virus

We evaluated pandemic influenza A (H1N1) 2009 virus isolates and respiratory tissues collected at autopsy by electron microscopy. Many morphologic characteristics were similar to those previously described for influenza virus. One of the distinctive features was dense tubular structures in the nuclei of infected cells.     

海南省甲型H1N1流感血清流行病学调查

目的了解海南省2009年甲型H1N1流感大流行高峰后期人群感染水平及流行趋势。方法于2009年12月和2010年1-3月共5次在海口市抽取医院门诊患者、血液中心志愿者,利用血凝抑制(HI)方法进行血清标本甲型H1N1流感抗体检测。结果 5次调查的人群抗体阳性率依次为10.50%(40/381)、16.06%(62/386)、31.35%(121/386)、23.16%(91/393)和38.02%(146/384),随时间推移总体呈增长趋势(χ2=81.17,P<0.05);除0～5岁组外,6～17岁、18～55岁及≥56岁组抗体阳性率均随时间推移而上升(χ2=4.22,P>0.05;χ2=21.25,P<0.05;χ2=39.05,P<0.05;χ2=26.85,P<0.05);6～17岁组抗体阳性率5次调查均最高。结论海南省甲型H1N1流感人群免疫水平逐步提高,该疾病在海南省的流行将维持在较低水平;6～17岁人群为主要感染人群。     

Pandemic (H1N1) 2009 Vaccination and Class Suspensions after Outbreaks, Taipei City, Taiwan

In Taipei City, class suspensions were implemented beginning September 1, 2009 when transmission of pandemic (H1N1) 2009 infection was suspected. The uptake rate of pandemic (H1N1) 2009 vaccination (starting on November 16, 2009) among students 7–18 years of age was 74.7%. Outbreaks were mitigated after late November 2009.     

Hospitalized patients with pandemic (H1N1) 2009, Kenya

To describe the epidemiology and clinical course of patients hospitalized with pandemic (H1N1) 2009 in Kenya, we reviewed medical records of 49 such patients hospitalized during July-November 2009. The median age (7 years) was lower than that in industrialized countries. More patients had HIV than the general Kenyan population.     

Pandemic (H1N1) 2009 Surveillance and Prevalence of Seasonal Influenza, Singapore

On April 25, 2009, Singapore implemented strict containment measures for pandemic (H1N1) 2009 with enhanced surveillance and hospital isolation. In the first month, seasonal influenza, predominantly virus subtype H3N2, was diagnosed for 32% of patients with acute febrile respiratory illness. Our findings underscore the high prevalence of seasonal influenza in Singapore.     

Reassortment of ancient neuraminidase and recent hemagglutinin in pandemic (H1N1) 2009 virus

Sequence analyses show that the outbreak of pandemic (H1N1) 2009 resulted from the spread of a recently derived hemagglutinin through a population of ancient and more diverse neuraminidase segments. This pattern implies reassortment and suggests that the novel form of hemagglutinin conferred a selective advantage.     

Pandemic (H1N1) 2009 Virus on Commercial Swine Farm, Thailand

A swine influenza outbreak occurred on a commercial pig farm in Thailand. Outbreak investigation indicated that pigs were co-infected with pandemic (H1N1) 2009 virus and seasonal influenza (H1N1) viruses. No evidence of gene reassortment or pig-to-human transmission of pandemic (H1N1) 2009 virus was found during the outbreak.     

Pandemic (H1N1) 2009 and Hajj Pilgrims Who Received Predeparture Vaccination, Egypt

In Egypt, vaccination against pandemic (H1N1) 2009 virus was required of pilgrims departing for the 2009 Hajj. A survey of 551 pilgrims as they returned to Egypt found 542 (98.1% [weighted]) reported receiving the vaccine; 6 (1.0% [weighted]) were infected with influenza virus A (H3N2) but none with pandemic (H1N1) 2009 virus.     

Characteristics of children hospitalized for pandemic (H1N1) 2009, Malaysia

To determine effects of pandemic (H1N1) 2009 on children in the tropics, we examined characteristics of children hospitalized for this disease in Malaysia. Of 1,362 children, 51 (3.7%) died, 46 of whom were in an intensive care unit. Although disease was usually mild, ≥ 1 concurrent conditions were associated with higher death rates.