Question

1. What is the Influenza virus, and why has it been a concern to public health as far back as 1918 until today? Make sure to address 5 key issues: viral transmission method, viral strains, disease symptoms and lethality, viral evolution, and vaccine development (30 points; 6 points each issue). 2. A seasonal vaccine for the Influenza virus is currently available, and public health officials generally argue that the benefits of flu vaccinations outweigh the risks, so that health workers generally recommend taking the vaccine. Do you agree with this viewpoint? Why or why not? (10 points) 3. Public health officials contend that a national flu vaccination campaign will alleviate some of the pressures on hospital resources in terms of supplies, staff, space, etc. Do you agree with this argument? Why or why not? (10 pts)

Answer 1

1).

Influenza is caused by a "flu virus (H1N1)." Different types of influenza viruses include type 1, type 2, and type 3.

H1N1 virus spread is due to severe exposure to zoonotic animals (carriers) such as pigs. This virus is pandemic due to its structural complexity of viral lipid membrane with spikes. These spikes are to act as an antigen in the host and also due to extremely fast RNA replication. Its genome is highly complemented with host genome and result in host body produces antibodies (immune response) thereby only during the production immune response to the flu virus result in disease symptoms.

Signs and symptoms of the disease: Muscle pains, dry cough with phlegm (mild), chills, fever, loss of appetite, fatigue, runny nose, sneezing, throat irritation or a sore throat.

The common mode of transmission is through droplets of a cough, sneezing, etc or through direct contact with the patient secretions.

The genetic reassortment (mixing of genetic material) is possible with the influenza virus as its genome consists of eight RNA segments. Previously, the occurrence of influenza pandemics was evidenced by the reassortment between the human and avian virus forms, and also the recent H1N1 outbreak is also a result of genetic reassortment.

Geography, discovery, reasons for emergence Mechanisms of potential worldwide spread: The most lethal viral event in the last 100 years is the Spanish flu pandemic. It is a culling event because the 1918 Influenza Strain was extremely Virulent because of the presence of hemagglutinin (HA), neuraminidase protein leading to different levels of pathogenicity. Approximately 20 to 100 million people were killed during this pandemic attack.

H1N1 influenza has been the cause of four pandemics in recent history: 1918, 1957, 1968, and 2009. The fast RNA replication property of the virus made it evolve the antigenic shift so that the same virus can efficiently attack different times though we developed resistance to any one type or two types of the virus.

We need to take influenza vaccine every year because the influenza viruses adapt to the developed immunity and evolve new virions that are not sensitive to the previous vaccines. So, influenza vaccines are released every year according to the newly evolved strains.