Influenza: Difference between revisions

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==[[Influenza future or investigational therapies|Future or Investigational Therapies]]==
==[[Influenza future or investigational therapies|Future or Investigational Therapies]]==


==Infection in other animals==
==[[Influenza causes|Causes of Influenza]]==
{{H5N1}}{{further|[[Influenzavirus A]], [[H5N1]] and [[Transmission and infection of H5N1]]}}
Influenza infects many animal species and transfer of viral strains between species can occur. Birds are thought to be the main [[host (biology)|animal reservoir]]s of influenza viruses.<ref>{{cite journal | author = Gorman O, Bean W, Kawaoka Y, Webster R | title = Evolution of the nucleoprotein gene of influenza A virus. | url=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=2319644 | journal = J Virol | volume = 64 | issue = 4 | pages = 1487–97 | year = 1990 | id = PMID 2319644}}</ref> Sixteen forms of [[hemagglutinin]] and 9 forms of [[neuraminidase]] have been identified. All known subtypes (HxNy) are found in birds but many subtypes are endemic in humans, dogs, horses, and pigs; populations of camels, ferrets, cats, seals, mink, and whales also show evidence of prior infection or exposure to influenza.<ref name=webster/> Variants of flu virus are sometimes named according to the species the strain is endemic in or adapted to. The main variants named using this convention are: Bird flu, [[Human flu|Human Flu]], Swine Flu, Horse Flu and Dog Flu. (Cat flu generally refers to Feline viral rhinotracheitis or Feline calicivirus and not infection from an influenza virus.) In pigs, horses and dogs, influenza symptoms are similar to humans, with cough, fever and loss of appetite.<ref name=webster/> The frequency of animal diseases are not as well-studied as human infection, but an outbreak of influenza in harbour seals caused approximately 500 seal deaths off the New England coast in 1979–1980.<ref>{{cite journal | author = Hinshaw V, Bean W, Webster R, Rehg J, Fiorelli P, Early G, Geraci J, St Aubin D | title = Are seals frequently infected with avian influenza viruses? | url=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=6471169 | journal = J Virol | volume = 51 | issue = 3 | pages = 863-5 | year = 1984 | id = PMID 6471169}}</ref> On the other hand, outbreaks in pigs are common and do not cause severe mortality.<ref name=webster/>
 
Flu symptoms in birds are variable and can be unspecific.<ref>{{cite journal | author = Elbers A, Koch G, Bouma A | title = Performance of clinical signs in poultry for the detection of outbreaks during the avian influenza A (H7N7) epidemic in The Netherlands in 2003. | journal = Avian Pathol | volume = 34 | issue = 3 | pages = 181-7 | year = 2005 | id = PMID 16191700}}</ref> The symptoms following infection with low-pathogenicity avian influenza may be as mild as ruffled feathers, a small reduction in egg production, or weight loss combined with minor respiratory disease.<ref>Capua I, Mutinelli F. "Low pathogenicity (LPAI) and highly pathogenic (HPAI) avian influenza in turkeys and chicken." In: Capua I, Mutinelli F. (eds.), A Colour Atlas and Text on Avian Influenza, Papi Editore, Bologna, 2001, pp. 13–20</ref> Since these mild symptoms can make diagnosis in the field difficult, tracking the spread of avian influenza requires laboratory testing of samples from infected birds. Some strains such as Asian [[H9N2]] are highly virulent to poultry, and may cause more extreme symptoms and significant mortality.<ref>{{cite journal | author = Bano S, Naeem K, Malik S | title = Evaluation of pathogenic potential of avian influenza virus serotype H9N2 in chickens. | journal = Avian Dis | volume = 47 | issue = 3 Suppl | pages = 817-22 | year = 2003 | id = PMID 14575070}}</ref> In its most highly pathogenic form, influenza in chickens and turkeys produces a sudden appearance of severe symptoms and almost 100% mortality within two days.<ref>{{cite journal | author = Swayne D, Suarez D | title = Highly pathogenic avian influenza. | journal = Rev Sci Tech | volume = 19 | issue = 2 | pages = 463-82 | year = 2000 | id = PMID 10935274}}</ref> As the virus spreads rapidly in the crowded conditions seen in the intensive farming of chickens and turkeys, these outbreaks can cause large economic losses to poultry farmers.
 
An avian-adapted, highly pathogenic strain of H5N1 (called HPAI A(H5N1), for "highly pathogenic avian influenza virus of type A of subtype H5N1") causes [[transmission and infection of H5N1|H5N1 flu]], commonly known as "avian influenza" or simply "bird flu", and is [[endemic (epidemiology)|endemic]] in many bird populations, especially in Southeast Asia. This Asian lineage strain of HPAI A(H5N1) is [[global spread of H5N1|spreading globally]]. It is [[epizootic]] (an epidemic in non-humans) and panzootic (a disease affecting animals of many species, especially over a wide area) killing tens of millions of birds and spurring the culling of hundreds of millions of other birds in an attempt to control its spread. Most references in the media to "bird flu" and most references to H5N1 are about this specific strain.<ref>{{cite journal | author = Li K, Guan Y, Wang J, Smith G, Xu K, Duan L, Rahardjo A, Puthavathana P, Buranathai C, Nguyen T, Estoepangestie A, Chaisingh A, Auewarakul P, Long H, Hanh N, Webby R, Poon L, Chen H, Shortridge K, Yuen K, Webster R, Peiris J | title = Genesis of a highly pathogenic and potentially pandemic H5N1 influenza virus in eastern Asia. | journal = Nature | volume = 430 | issue = 6996 | pages = 209-13 | year = 2004 | id = PMID 15241415}}</ref><ref>Li KS, Guan Y, Wang J, Smith GJ, Xu KM, Duan L, Rahardjo AP, Puthavathana P, Buranathai C, Nguyen TD, Estoepangestie AT, Chaisingh A, Auewarakul P, Long HT, Hanh NT, Webby RJ, Poon LL, Chen H, Shortridge KF, Yuen KY, Webster RG, Peiris JS. [http://darwin.nap.edu/books/0309095042/html/116.html "The Threat of Pandemic Influenza: Are We Ready?" Workshop Summary] The National Academies Press (2005) "Today's Pandemic Threat: Genesis of a Highly Pathogenic and Potentially Pandemic H5N1 Influenza Virus in Eastern Asia", pages 116–130</ref>
 
At present, HPAI A(H5N1) is an avian disease and there is no evidence suggesting efficient human-to-human transmission of HPAI A(H5N1). In almost all cases, those infected have had extensive physical contact with infected birds.<ref>{{cite journal | author = Liu J | title = Avian influenza—a pandemic waiting to happen? | url=http://jmii.org/content/pdf/v39n1p4.pdf | journal = J Microbiol Immunol Infect | volume = 39 | issue = 1 | pages = 4–10 | year = 2006 | id = PMID 16440117}}</ref> In the future, H5N1 may mutate or reassort into a strain capable of efficient human-to-human transmission. Due to its high lethality and [[virulence]], its [[endemic (epidemiology)|endemic]] presence, and its large and increasing biological host reservoir, the H5N1 virus is the world's pandemic threat in the 2006–7 flu season, and billions of dollars are being raised and spent researching H5N1 and preparing for a potential [[influenza pandemic]].<ref name=Rosenthal> Rosenthal, E. and Bradsher, K. [http://www.nytimes.com/2006/03/16/business/16bird.html?_r=1&oref=slogin Is Business Ready for a Flu Pandemic?] The New York Times 16-03-2006 Accessed 17-04-2006</ref>


==[[Influenza cost-effectiveness of therapy|Cost-Effectiveness of Therapy]]==
==[[Influenza cost-effectiveness of therapy|Cost-Effectiveness of Therapy]]==

Revision as of 22:38, 9 January 2012

Influenza Microchapters

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Influenza
TEM of negatively stained influenza virons, magnified approximately 70,000 times
ICD-10 J10, J11
ICD-9 487
DiseasesDB 6791
MedlinePlus 000080
MeSH D007251

Template:Flu

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

Overview

Historical perspective

Classification

Diagnosis

History & Symptoms

Lab Tests

Epidemiology & Demographics

Primary Prevention

Medical Therapy

Future or Investigational Therapies

Causes of Influenza

Cost-Effectiveness of Therapy

See also

Information concerning flu research can be found at

References and notes

Further reading

Template:Col-1-of-2General
  • NEJM's Avian Influenza
  • Bernd Sebastian Kamps, Christian Hoffmann and Wolfgang Preiser (Eds.) Influenza Report 2006 Flying publisher 2006.
  • Arnold J. Levine 'Viruses' Scientific American Library, WH Freeman, 1992 ISBN 0-7167-5031-7
  • Samuel Baron et al. 'Medical Microbiology' Fourth Edition, The University of Texas Medical Branch at Galveston 1996 ISBN 0-9631172-1-1.
  • Cox NJ, Subbarao K. 'Influenza.' Lancet. 1999 Oct 9;354(9186):1277–82. PMID 10520648
History
  • Edwin D. Kilbourne Influenza Pandemics of the 20th Century Emerging Infectious Diseases Special Issue: Influenza Vol. 12, No. 1 January 2006
  • Richard Collier 'The Plague of the Spanish Lady' Macmillan publishers (London) 1974 ISBN 0-7490-0246-8
  • John M. Barry 'The Great Influenza: the Epic Story of the Deadliest Plague in History' Penguin 2004 ISBN 0-670-89473-7
Microbiology
  • Webster RG, Bean WJ, Gorman OT, Chambers TM, Kawaoka Y. "Evolution and ecology of influenza A viruses." Microbiol Rev. 1992 Mar;56(1):152–79. PMID 1579108
  • Scholtissek C. 'Molecular epidemiology of influenza.' Arch Virol Suppl. 1997;13:99–103. PMID 9413530
Template:Col-2-of-2Pathogenesis
  • Adolfo García-Sastre Antiviral Response in Pandemic Influenza Viruses 'Emerging Infectious Diseases Special Issue: Influenza Vol. 12, No. 1 January 2006
  • Zambon MC. 'The pathogenesis of influenza in humans.' Rev Med Virol. 2001 Jul–Aug;11(4):227–41. PMID 11479929
EpidemiologyTreatment and preventionResearch

External links

Influenza Microchapters

Home

Patient Information

Overview

Historical Perspective

Classification

Pathophysiology

Causes

Differentiating Influenza from other Diseases

Epidemiology and Demographics

Risk Factors

Natural History, Complications and Prognosis

Diagnosis

History and Symptoms

Physical Examination

Laboratory Findings

Chest X Ray

Other Diagnostic Studies

Treatment

Medical Therapy

Primary Prevention

Cost-Effectiveness of Therapy

Future or Investigational Therapies

Case Studies

Case #1

Influenza On the Web

Most recent articles

Most cited articles

Review articles

CME Programs

Powerpoint slides

Images

American Roentgen Ray Society Images of Influenza

All Images
X-rays
Echo & Ultrasound
CT Images
MRI

Ongoing Trials at Clinical Trials.gov

US National Guidelines Clearinghouse

NICE Guidance

FDA on Influenza

CDC on Influenza

Influenza in the news

Blogs on Influenza

Directions to Hospitals Treating Influenza

Risk calculators and risk factors for Influenza

Template:Respiratory pathology Template:Viral diseases Template:Link FA

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