H5N1 avian influenza virus: an overview

Proença-Módena, José Luiz; Macedo, Izolete Santos; Arruda, Eurico

doi:10.1590/s1413-86702007000100027

Cited by 23 publications

(14 citation statements)

References 78 publications

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“…The specter of an influenza pandemic continues to threaten, with annual outbreaks of highly-pathogenic H5N1 in birds [1] and continued sporadic human H5N1 cases and clusters [2] with some reports that suggested limited, non sustained human-to-human transmission of H5N1 viruses [3,4]. If a pandemic virus strain were to emerge, pre-pandemic vaccines would be available to some populations although of unknown efficacy, but development and distribution of initial doses of influenza vaccine specifically made against the pandemic strain would not be available for at least 4-6 months [5].…”

Section: Introductionmentioning

confidence: 99%

Preliminary Findings of a Randomized Trial of Non-Pharmaceutical Interventions to Prevent Influenza Transmission in Households

et al. 2008

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BackgroundThere are sparse data on whether non-pharmaceutical interventions can reduce the spread of influenza. We implemented a study of the feasibility and efficacy of face masks and hand hygiene to reduce influenza transmission among Hong Kong household members.Methodology/Principal FindingsWe conducted a cluster randomized controlled trial of households (composed of at least 3 members) where an index subject presented with influenza-like-illness of <48 hours duration. After influenza was confirmed in an index case by the QuickVue Influenza A+B rapid test, the household of the index subject was randomized to 1) control or 2) surgical face masks or 3) hand hygiene. Households were visited within 36 hours, and 3, 6 and 9 days later. Nose and throat swabs were collected from index subjects and all household contacts at each home visit and tested by viral culture. The primary outcome measure was laboratory culture confirmed influenza in a household contact; the secondary outcome was clinically diagnosed influenza (by self-reported symptoms). We randomized 198 households and completed follow up home visits in 128; the index cases in 122 of those households had laboratory-confirmed influenza. There were 21 household contacts with laboratory confirmed influenza corresponding to a secondary attack ratio of 6%. Clinical secondary attack ratios varied from 5% to 18% depending on case definitions. The laboratory-based or clinical secondary attack ratios did not significantly differ across the intervention arms. Adherence to interventions was variable.Conclusions/SignificanceThe secondary attack ratios were lower than anticipated, and lower than reported in other countries, perhaps due to differing patterns of susceptibility, lack of significant antigenic drift in circulating influenza virus strains recently, and/or issues related to the symptomatic recruitment design. Lessons learnt from this pilot have informed changes for the main study in 2008.Trial RegistrationClinicalTrials.gov NCT00425893 HKClinicalTrials.com HKCTR-365

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Section: Introductionmentioning

confidence: 99%

Preliminary Findings of a Randomized Trial of Non-Pharmaceutical Interventions to Prevent Influenza Transmission in Households

et al. 2008

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“…In addition, these viruses mutate from year to year to cause even worldwide pandemics (Ghedin et al 2005). In the 20th century, at least four pandemics of influenza occurred, which killed approximately 100 million people around the world at irregular intervals (Proença-Módena et al 2007). In 1997, a highly pathogenic avian influenza virus (H5N1) emerged in Hong Kong, causing severe human disease.…”

Section: Introductionmentioning

confidence: 99%

Quantification of Airborne Influenza and Avian Influenza Virus in a Wet Poultry Market using a Filter/Real-time qPCR Method

Chen

Lin

Tsai

et al. 2009

Aerosol Science and Technology

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Influenza viruses cause pandemics in humans. The aim of this study was therefore to evaluate filter/real-time qPCR to quickly and accurately determine and quantify the airborne influenza and avian influenza virus. In this study, the sampling stress of filtration to influenza virus and the storage effects for both the virus and extracted RNA were evaluated in the laboratory. Then, the collection efficiencies of open-face and closed-face filter cassettes were compared in a wet poultry market. From July 8 to August 19, 2006, a total of 36 air samples were quantified by filter/real-time qPCR.The recovery rate of the virus on a filter stored at 4• C reached 0.94 after 3-day storage, whereas the RNA stored at -80• C was 100% after 3-month storage. In terms of collection efficiency, the closed-face filter cassette was superior to the open-face filter cassette in the field study. In the wet poultry market, it was revealed that both the positive rate and concentration of influenza A virus in the chicken pen were higher than that in the duck pen, possibly due to differences in ventilation type, climate factors, and avian characteristics. To our knowledge, this is the first report describing the quantification of airborne influenza virus in field samples. This quantitative technique should provide more insight into influenza/avian influenza virus transmissibility and epidemiology of influenza/avian influenza, as well as infection control.

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“…[19–20] Avian influenza exists in both low-pathogenic and high-pathogenic forms differing in its inherent ability to harm its host, and its capacity to spread between and among various host species. Low pathogenic avian influenza (LPAI) does not cause any illness in domestic poultry while an H5 or H7 LPAI strain posses significant potential to evolve into a highly pathogenic avian influenza (HPAI) strain.…”

Section: Emergence Of Flu Outbreaks As Future Pandemicsmentioning

confidence: 99%

Mitigation approaches to combat the flu pandemic

Chawla

Sharma

Madaan

et al. 2009

J Global Infect Dis

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Management of flu pandemic is a perpetual challenge for the medical fraternity since time immemorial. Animal to human transmission has been observed thrice in the last century within an average range of 11-39 years of antigenic recycling. The recent outbreak of influenza A (H1N1, also termed as swine flu), first reported in Mexico on April 26, 2009, occurred in the forty first year since last reported flu pandemic (July 1968). Within less than 50 days, it has assumed pandemic proportions (phase VI) affecting over 76 countries with 163 deaths/35,928 cases (as on 15th June 2009). It indicated the re-emergence of genetically reassorted virus having strains endemic to humans, swine and avian (H5N1). The World Health Organisation (WHO) member states have already pulled up their socks and geared up to combat such criticalities. Earlier outbreaks of avian flu (H5N1) in different countries led WHO to develop pandemic preparedness strategies with national/regional plans on pandemic preparedness. Numerous factors related to climatic conditions, socio-economic strata, governance and sharing of information/logistics at all levels have been considered critical indicators in monitoring the dynamics of escalation towards a pandemic situation.The National Disaster Management Authority (NDMA), Government of India, with the active cooperation of UN agencies and other stakeholders/experts has formulated a concept paper on role of nonhealth service providers during pandemics in April 2008 and released national guidelines - management of biological disasters in July 2008. These guidelines enumerate that the success of medical management endeavors like pharmaceutical (anti-viral Oseltamivir and Zanamivir therapies), nonpharmaceutical interventions and vaccination development etc., largely depends on level of resistance offered by mutagenic viral strain and rationale use of pharmaco therapeutic interventions. This article describes the mitigation approach to combat flu pandemic with its effective implementation at national, state and local levels.

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H5N1 avian influenza virus: an overview

Cited by 23 publications

References 78 publications

Preliminary Findings of a Randomized Trial of Non-Pharmaceutical Interventions to Prevent Influenza Transmission in Households

Preliminary Findings of a Randomized Trial of Non-Pharmaceutical Interventions to Prevent Influenza Transmission in Households

Quantification of Airborne Influenza and Avian Influenza Virus in a Wet Poultry Market using a Filter/Real-time qPCR Method

Mitigation approaches to combat the flu pandemic

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