Is it Bird Flu or Human Flu?

Assignment title: Is it Bird Flu or Human Flu
Subject: Medical Microbiology and Immunology
Mark: 8/10 lost two points for needing more specific information and missing the websites on the reference list.

Criteria

1. Identify the pathogen(s) involved. 
2. Outline the type of immune defenses that might be operating.
3. How does the pathogen enter the body, cause disease and how is it transmitted?
4. What is the outcome of the infection?
5. How is the disease diagnosed? What strategies exist (if any) to control the infection?
6. References

Is it Bird Flu or Human Flu?

The Enemy - Microbes

Avian Influenza A, also known as H5N1 or Bird Flu, is an enzootic member of the orthomyxoviridae family, representing an enveloped, ssRNA viral molecule, with surface hemagglutinin and neuraminidase surface glycoproteins. (1)

The Defence - Host Disease

H5N1 is more prevalent in birds in China, Asia, Europe and Africa, however, mutations have crossed the animal to human barrier causing destructive and fatal consequences for many individuals around the world due to individuals carrying the virus internally. (2)

The War - Infection, and Transmission of Disease

Surface hemagglutinin and neuraminidase antigenic glycoproteins found on H5N1 molecules attach to type 2 pneumocytes and macrophages and alpha-2-3 sialic acid receptors found on human ciliated respiratory epithelial cells, preferably on alveolar epithelial cells expressing alpha 2-3 SA galactose-N-acetylglucosamine in the lower respiratory tract. This blocks cleansing mechanisms in the airways. (3)

The Casualty - Clinical Manifestations

H5N1 has an incubation period of 2-8 days however cases up to 17 days have been recorded. Initial symptoms express flu-like characteristics including a high fever above 38 degrees Celcius, cough, headache, muscle aches, mucous production, sore throat, and malaise. Other symptoms accompanying H5N1virus include abdominal and chest pain, diarrhea, respiratory distress, vomiting and nose and gum blood loss. (2)

H5N1 is a biological deteriorating infection with a 60% chance of fatality. Viral treatment within 48 hours gives the infected individual the best chance of survival. (2)

The Victory - Diagnosis, and Control

Assay tests, white blood cell differentials and nasopharyngeal culture are completed on infected individuals to diagnose the particular strain of influenza causing the disease. The doctor can also perform chest x-rays and auscultation tests to detect abnormal lung function as well as other internal organ tests if the individual is having severe symptoms (5)

Treatment with antiviral medication Oseltamivir within 48 hours post onset of symptoms has been reported to increase recovery prognosis (5). Various vaccines have been developed to avert a pandemic however the best control of H5N1 is prevention. H5N1 spread and mutation can be reduced with proper hygiene practices, evading contaminated surfaces, avoiding live-bird markets with an H5N1 outbreak, ensuring bird items are thoroughly cooked and people working with infected birds should wear protective clothing and special breathing masks (5).

Bibliography

1. R.B Couch. Orthomyxoviruses. (ebook) Medical Microbiology. 4th ed. Galveston (TX): University of Texas Medical Branch at Galveston; 1996. Chapter 58
2. The Writing Committee of the World Health Organisation (WHO) Avian Influenza WHO website: Media Center - Factsheet
3. C.Y Cheung, C.Y.H Leung, J.M Nicholls & J.s.M Peiris Innate immune responses to influenza A H5N1: friend or foe? Trends in Immunology, 30,12 (2009) pp.574-584
4. Centers for Disease Control and Prevention (CD) Seasonal Influenza (flu): Information on Avian Influenza CDC Website: reviewed June 21st 2012, updated June 22nd 2012
5. L.J Vorvick & D Zieve. The University of Washington, School of Medicine Avian Influenza: Bird Flu; H5N1