Evidence for avian influenza A infections among Iowa's agricultural workers

Background Identifying risk factors for zoonotic influenza transmission may aid public health officials in pandemic influenza planning. Objectives We sought to evaluate rural Iowan agriculture workers exposed to poultry for previous evidence of avian influenza virus infection. Methods In 2004, we enrolled 803 rural adult Iowans in a 2‐year prospective study of zoonotic influenza transmission. Their enrollment data and sera were compared with those of 66 adult controls enrolled at the University of Iowa in 2006 by using proportional odds modeling. Results Of the 803 participants 58·8% were male with a mean age of 55·6 years. Forty‐eight percent reported previous poultry exposure. Sera were studied by microneutralization techniques for antibodies against avian H4, H5, H6, H7 and H9 viruses. Touching live birds was associated (OR 1·2; 95% CI 1·02–1·8) with increased antibody titer against H5 virus. Similarly, participants who reported hunting wild birds had increased antibody titers against H7 virus (OR 2·8; 95%CI 1·2–6·5) and subjects who reported recent exposure to poultry had increased antibody titers against H6 (OR 3·4; 95% CI 1·4–8·5) and H7 viruses (OR 2·5, 95% CI 1·1–5·7). There was no evidence of elevated antibody against avian H4 or H9 viruses. Conclusions These data suggest that hunting and exposure to poultry may be important risk factors for avian influenza virus infection among rural US populations. Agriculture workers should be included in influenza pandemic plans.     

Sparse evidence for equine or avian influenza virus infections among Mongolian adults with animal exposures

In recent years, Mongolia has experienced recurrent epizootics of equine influenza virus (EIV) among its 2·1 million horses and multiple incursions of highly pathogenic avian influenza (HPAI) virus via migrating birds. No human EIV or HPAI infections have been reported. In 2009, 439 adults in Mongolia were enrolled in a population‐based study of zoonotic influenza transmission. Enrollment sera were examined for serological evidence of infection with nine avian, three human, and one equine influenza virus strains. Seroreactivity was sparse among participants suggesting little human risk of zoonotic influenza infection.     

Newer respiratory virus infections: human metapneumovirus, avian influenza virus, and human coronaviruses

PURPOSE OF REVIEW: Recently, several previously unrecognized respiratory viral pathogens have been identified and several influenza A virus subtypes, previously known to infect poultry and wild birds, were transmitted to humans. Here we review the recent literature on these respiratory viruses. RECENT FINDINGS: Human metapneumovirus has now been detected worldwide, causing severe respiratory tract illnesses primarily in very young, elderly and immunocompromised individuals. Animal models and reverse genetic techniques were designed for human metapneumovirus, and the first vaccine candidates have been developed. Considerable genetic and antigenic diversity was observed for human metapneumovirus, but the implication of this diversity for vaccine development and virus epidemiology requires further study. Two previously unrecognized human coronaviruses were discovered in 2004 in The Netherlands and Hong Kong. Their clinical impact and epidemiology are largely unknown and warrant further investigation. Several influenza A virus subtypes were transmitted from birds to humans, and these viruses continue to constitute a pandemic threat. The clinical symptoms associated with these zoonotic transmissions range from mild respiratory illnesses and conjunctivitis to pneumonia and acute respiratory distress syndrome, sometimes resulting in death. More basic research into virus ecology and evolution and development of effective vaccines and antiviral strategies are required to limit the impact of influenza A virus zoonoses and the threat of an influenza pandemic. SUMMARY: Previously unknown and emerging respiratory viruses are an important threat to human health. Development of virus diagnostic tests, antiviral strategies, and vaccines for each of these pathogens is crucial to limit their impact.     

Herpes simplex virus infections among rural residents in eastern China

Background  

Herpes simplex virus (HSV) has two types: HSV-1 and HSV-2. Both infect epithelial cells and establish latent infections in neurons causing an infection that persists for life. Information on age- and gender-specific seroprevalence of HSV-1 and HSV-2 is valuable for understanding HSV transmission dynamics and designing population-based prevention and intervention programs for HSV. However, such information is not available for China.     

人感染高致病性禽流感病毒病原学特点分析与启示

本文对近年频繁发牛的人感染高致病性禽流感病毒病原学特点、流行状况、传播途径、以及病毒致病的分子生物学基础进行了分析,并强调了进一步加强国际合作研究的重要性。     

Ecology of avian influenza virus in birds

Avian influenza A virus (an orthomyxovirus) is a zoonotic pathogen with a natural reservoir entirely in birds. The influenza virus genome is an 8-segment single-stranded RNA with high potential for in situ recombination. Two segments code for the hemagglutinin (H) and neuraminidase (N) antigens used for host-cell entry. At present, 16 H and 9 N subtypes are known, for a total of 144 possible different influenza subtypes, each with potentially different host susceptibility. With >10,000 species of birds found in nearly every terrestrial and aquatic habitat, there are few places on earth where birds cannot be found. The avian immune system differs from that of humans in several important features, including asynchronous B and T lymphocyte systems and a polymorphic multigene immune complex, but little is known about the immunogenetics of pathogenic response. Postbreeding dispersal and migration and a naturally high degree of environmental vagility mean that wild birds have the potential to be vectors that transmit highly pathogenic variants great distances from the original sources of infection.     

Avian influenza virus infections in humans

Seroepidemiologic and virologic studies since 1889 suggested that human influenza pandemics were caused by H1, H2, and H3 subtypes of influenza A viruses. If not for the 1997 avian A/H5N1 outbreak in Hong Kong of China, subtype H2 is the likely candidate for the next pandemic. However, unlike previous poultry outbreaks of highly pathogenic avian influenza due to H5 that were controlled by depopulation with or without vaccination, the presently circulating A/H5N1 genotype Z virus has since been spreading from Southern China to other parts of the world. Migratory birds and, less likely, bird trafficking are believed to be globalizing the avian influenza A/H5N1 epidemic in poultry. More than 200 human cases of avian influenza virus infection due to A/H5, A/H7, and A/H9 subtypes mainly as a result of poultry-to-human transmission have been reported with a > 50% case fatality rate for A/H5N1 infections. A mutant or reassortant virus capable of efficient human-to-human transmission could trigger another influenza pandemic. The recent isolation of this virus in extrapulmonary sites of human diseases suggests that the high fatality of this infection may be more than just the result of a cytokine storm triggered by the pulmonary disease. The emergence of resistance to adamantanes (amantadine and rimantadine) and recently oseltamivir while H5N1 vaccines are still at the developmental stage of phase I clinical trial are causes for grave concern. Moreover, the to-be pandemic strain may have little cross immunogenicity to the presently tested vaccine strain. The relative importance and usefulness of airborne, droplet, or contact precautions in infection control are still uncertain. Laboratory-acquired avian influenza H7N7 has been reported, and the laboratory strains of human influenza H2N2 could also be the cause of another pandemic. The control of this impending disaster requires more research in addition to national and international preparedness at various levels. The epidemiology, virology, clinical features, laboratory diagnosis, management, and hospital infection control measures are reviewed from a clinical perspective.     

生物信息学在禽流感病毒研究中的应用

生物信息学自诞生之日起,其技术手段便在生物学、医学、农学和药学等领域的研究中得到广泛应用。虽然病毒学研究有其自身的特点和规律,但生物信息学已深入到禽流感病毒研究的各个层次,从微观的禽流感病毒基因组遗传变异到宏观的禽流感病毒的扩散等都有生物信息学的应用。本文简要综述了生物信息学在禽流感研究中的应用。     

Recovery of Cyclospora cayetanensis among asymptomatic rural Thai schoolchildren

Objective:To obtain the prevalence with clinical symptoms of Cyclospora cayetanensis(C.cayetanensis),a coceidian protozoan parasite,in Thailand which is the cause of an intestinal infection characterized by sporadic-to-frequent explosive diarrhea.Methods:In a field surveyconducted by the Faculty of Tropical Medicine.Mahidol Lniversity.as part of the existing parasite-control program,a total of 2 540 faecal samples from villagers in Nan Province,Thailand,were collected and examined to determine the prevalence and clinical characteristics of parasitic infections.Results:Twelve cases of C.cayetanensis infection were found duritig faecal examination of schoolchildren aged 5-12 years.None exhibited obvious clinical symptoms,especially evidence of diarrhea:5 of 12 had loose faeces,one reported frequent symptoms of abdominal discomfort,and another had pale conjunctiva with low hematocrit.The children were generally asymptomatic.Conclusions:This finding confirms a public-health issue with potentially serious consequences whereby children can be exposed to an environment contaminated with food-und water-borne transmitted oocysts,anil can hence become infected with C.cayetunensis.     

Planning for avian influenza

Avian influenza, or influenza A (H5N1), has 3 of the 4 properties necessary to cause a serious pandemic: It can infect people, nearly all people are immunologically naive, and it is highly lethal. The Achilles heel of the virus is the lack of sustained human-human transmission. Fortunately, among the 124 cases reported through 30 May 2006, nearly all were acquired by direct contact with poultry. Unfortunately, the capability for efficient human-human transmission requires only a single mutation by a virus that is notoriously genetically unstable, hence the need for a new vaccine each year for seasonal influenza. Influenza A (H5N1) is being compared to another avian strain, the agent of the "Spanish flu" of 1918-1919, which traversed the world in 3 months and caused an estimated 50 million deaths. The question is, are we ready for this type of pandemic? The answer is probably no. The main problems are the lack of an effective vaccine, very poor surge capacity, a health care system that could not accommodate even a modest pandemic, and erratic regional planning. It's time to get ready, and in the process be ready for bioterrorism, natural disasters, and epidemics of other infectious diseases.     

鹧鸪禽流感病毒和人流感病毒唾液酸受体分布特征

目的 探讨鹧鸪禽流感病毒和人流感病毒唾液酸受体分布特点及其作用。方法 用亲和组化法检测鹧鸪呼吸道与消化道流感病毒唾液酸受体的分布,荧光素Alexa488标记禽流感病毒H9N1和人流感病毒H1N1,分别与鹧鸪呼吸道、消化道各解剖部位组织细胞结合。结果 鹧鸪呼吸道同时表达SAα-2,3Gal和SAα-2,6Gal两种受体,但其消化道仅表达SAα-2,3Gal受体。SAα-2,3Gal受体在鹧鸪呼吸道各部位和消化道结肠上皮细胞呈强阳性弥漫分布;SAα-2,6Gal受体在呼吸道气管、支气管和次级支气管呈强阳性弥漫分布,而副支气管、消化道结肠均为缺乏或仅表达极少量。H9N1禽流感病毒与鹧鸪呼吸道各部位和消化道结肠均结合;人流感病毒H1N1与鹧鸪的气管、支气管、次级支气管结合,但未见与副支气管和结肠结合,此结果与鹧鸪呼吸道和消化道SAα-2,3Gal和SAα-2,6Gal受体分布总体一致。结论 鹧鸪同时表达SAα-2,3Gal和SAα-2,6Gal受体,能与禽流感病毒和人流感病毒结合,有助于禽流感病毒与人流感病毒基因重配,提示其可充当流感病毒潜在的中间宿主。     

Herpes simplex virus and genital infections in Thai pregnant women

Vaginal swabs were collected monthly from 100 asymptomatic Thai pregnant women as well as from 11 pregnant women with herpetic lesions of the vulva for isolations of HVH, mycoplasma and gonorrhoea. In asymptomatic mothers, 25% and 21% of cases were positive for HVH and mycoplasma respectively. Mixed infections of HVH and mycoplasma, and HVH and gonorrhoea were also found in 27% and 1% of cases respectively. Follow-up in asymptomatic pregnant women and those with herpetic lesions showed positive HVH fluctuations throughout the course of study. Positive HVH was recovered from 48% of amniotic fluid and 32% of breast milk of asymptomatic pregnant women with positive HVH genital isolates, and in 72.7% of aminotic fluid and 36.4% of breast milk in patients with herpetic lesions. HVH was also isolated from 84% of infants of asymptomatic mothers positive for HVH, and 100% of patients with herpetic ulcer. HVH was isolated most frequently from the throat and also from nose, eyes, and ears but with less frequency. IgM antibodies were found in three infants born of asymptomatic mother and in one infant of a mother with herpetic lesion. The low percentage of IgM antibody was interpreted to mean that the HVH isolated from the newborn infants were acquired during passage through the birth canal.     

Seroprevalence of avian influenza A/H5N1 among poultry farmers in rural Indonesia, 2007

Since 2003, about a third (> 150 cases) of human cases of highly pathogenic avian influenza (HPAI) A/H5N1 worldwide are reported from Indonesia. We measured the seroprevalence of H5N1 among Indonesian poultry farmers and assessed the risk factors for and knowledge of H5N1 infection. In 2007, poultry workers and farm residents were interviewed about risk factors for knowledge of and then examined for the seropositivity of H5N1 virus. Four hundred ninety-five of 622 farmers (80%) from 12 farms participated in the study. Of these, 71% were male, with a median age of 29 years. None tested positive for H5N1 virus. Masks were never worn by 54% of participants; 86% were afraid of becoming infected. For the preceding six months, 1 farm was confirmed as having poultry infected with H5N1 virus. No evidence of subclinical infection with avian influenza A/H5N1 virus was found among poultry farmers, although exposure of the farmers to this virus may have been limited. However, we recommend sustaining ongoing surveillance and control efforts.     

人感染高致病性禽流感的流行与预防

人感染高致病性禽流行性感冒（human infections with highly pathogenic avian influenza）简称人禽流感,是指人感染甲型禽流感病毒（avian influenza virus,AIV）某些亚型的毒株引起的急性呼吸道传染病。1997年5月,我国香港特别行政区1例3岁儿童死于不明原因的多脏器功能衰竭,同年8月经美国疾病预防和控制中心以及世界卫生组织（WHO）荷兰鹿特丹国家流感中心鉴定为禽甲型流感病毒H5N1引起的人类流感,这是世界上首次证实禽甲型流感病毒H5N1感染人类。     

人感染禽流感病毒病例在我国的分布情况北大核心CSCD

禽流感病毒(avian influenza virus,AIV)属于正黏病毒科、A型流感病毒属、单股负链RNA病毒。水禽是禽流感病毒的天然宿主,部分禽流感病毒亚型不但能引起禽类致病,还能导致人类患病甚至死亡,严重危害公众健康。迄今为止,在自然界中共发现16种HA亚型和9种NA亚型的禽流感病毒,本文就我国禽流感病毒感染人病例的发生分布情况进行分析研究,为预测禽流感病毒的发病规律和制定防控措施提供科学依据。     

High urine ttMA levels among fishermen from a Thai rural village

The ongoing industrialization of Thailand, a developing country in Southeast Asia, has put many occupations at high risk of benzene exposure. However, there are few reports about monitoring the biomarkers of benzene exposure among Thais. In this study, we report on high urine trans, trans-muconic acid (ttMA) levels among the fishermen of a rural community. Using high-performance liquid chromatography (HPLC) for urine ttMA determination, 49 subjects (30 fishermen and 19 control subjects) were studied. The mean urine ttMA level in fisherman (0.180 +/- 0.130 mg/g creatinine) was significantly higher than that of the control group (0.015 +/- 0.053 mg/g creatinine) (p < 0.05). We recommend the monitoring of urine ttMA in these workers. The monitoring of the possible benzene contamination of the water and fish is recommended for further study.