Question

Karen is a 22 year old Nursing student that works at the local supermarket in her hometown. It is now the winter season and thus the height of cold and flu season in her hometown. She’d never gotten vaccinated before and had always made it through “flu season” just fine. Additionally, her two best friends were both vaccinated against influenza last year and had still gotten sick. Upon discussing her concerns with them, both warned her against getting vaccinated and told her that vaccines did not work and would only make her sick. They also urged her to join an “anti-vaccine” group on Facebook that talked about the dangers of vaccines and how they could cause autism in children. While the warnings of friends as well as those in the online FB group were convincing, Karen was still conflicted in her decision as to what she should do. Since taking Microbiology at WCU and learning about viruses and the viral replication process, Karen became concerned about her own risk for acquiring the virus and becoming sick. Additionally, because she worked with the public on a daily basis at the supermarket, many of whom came in coughing and sneezing on a daily basis, as well as interacting with her classmates at school, Karen is now debating whether or not she should get the flu vaccination to protect her against this year’s seasonal flu outbreak. Thus, she decided to do further research to assist her in her decision. At the suggestion of her Microbiology professor, Karen goes online to the World Health Organization’s (WHO) website and the Centers for Disease Control and Prevention’s (CDC) website to learn more about influenza, the influenza vaccine, and her risk for acquiring the virus to assist her in her decision on whether or not to get vaccinated. She also logged into Mastering Microbiology via the study area of her course website to learn more about how viruses replicate in general. Upon clicking on the WHO website and the Mastering Microbiology Study Area materials, she came across the following two videos: (see below).

Karen also visited the CDC’s website. On their website, Karen was able to find the following additional info:

“Quick Facts on Influenza”

• There are four types of influenza viruses: A, B, C and D.
• Human influenza A and B viruses cause seasonal epidemics of disease almost every winter in the United States. The emergence of a new and very different influenza A virus to infect people can cause an influenza pandemic.
• Influenza type C infections generally cause a mild respiratory illness and are not thought to cause epidemics. Influenza D viruses primarily affect cattle and are not known to infect or cause illness in people.
• Influenza A viruses are divided into subtypes based on two proteins on the surface of the virus: the hemagglutinin (H) and the neuraminidase (N). There are 18 different hemagglutinin subtypes and 11 different neuraminidase subtypes. (H1 through H18 and N1 through N11 respectively.)
• Influenza A viruses can be further broken down into different strains. Current subtypes of influenza A viruses found in people are influenza A (H1N1) and influenza A (H3N2) viruses. In the spring of 2009, a new influenza A (H1N1) virus (CDC 2009 H1N1 Flu website) emerged to cause illness in people. This virus was very different from the human influenza A (H1N1) viruses circulating at that time. The new virus caused the first influenza pandemic in more than 40 years. That virus (often called “2009 H1N1”) has now replaced the H1N1 virus that was previously circulating in humans.

Discussion Questions:

1. 1.  What type of virus is influenza? What are the various modes of transmission through which it can be acquired?

2. 2.  What are the signs and symptoms of influenza? Should be antibiotics be used to treat this infection if Karen acquires it?

3. 3.  Based off of what you learned from watching the lecture videos and Mastering Micro Influenza video, how does influenza replicate once it enters the body?

4. 4.  What is antigenic drift (or genetic drift)? What is antigenic shift (or genetic shift)?

5. 5. Is it a reasonable gamble for Karen to skip the influenza vaccine this year? Why or why not?

6.  If Karen decides to get vaccinated this year, can she skip out on getting vaccinated during the next year’s seasonal flu outbreak? Why or why not?

7.      7.  Does the flu vaccine provide an individual with life-long immunity?

8. 8.  Why did Karen’s two best friends end up getting sick after getting vaccinated against influenza? What should she tell them to encourage them to get vaccinated in the

future?

9.       

Answer 1

Answer 1.1) Influenza Virus is a RNA virus belonging to family Orthomyxoviridae. Various modes of transmission through which it can be acquired are direct contact with the infected individuals, inhaling the contaminated aerosol, and touching the objects containing virus.

1.2) Signs and symptoms of influenza are running nose, fever, chills, sore throats, watery eyes, muscle ache, headache, and fatigue. No, antibiotics cannot be used to treat this infection because this is a viral disease and antibiotic can only treat bacterial infections.

1.3) Once the influenza virus enters the host cell the virus fuses with the cell’s endosomal membrane and nucleocapsid of the virus will travel to the host nucleus where primary transcription of the viral DNA takes place to produce necessary viral protein for further replication of the virus. After that, the positive strand and negative strand of the viral RNA is produced from the cRNA and the negative sense strand of the RNA will exit the nucleus into the host cytoplasm. In the cytoplasm the production of hem agglutination, neuraminidase, and matrix protein will start the budding process and after meaning with the eight RNA segments of the virus it will complete the formation of virus. Exit from the cell is taken by dissolving the Stalin acid receptors of the host cell membrane.

1.4) Antigenic drift- It is the phenomenon where the mutations are accumulated in the antibody binding site of the viral genetic material. This causes antibody resistance in the virus and makes them stronger by producing different and more resistant viral strains.

Antigenic shift- This phenomenon is caused when two strains of the same virus or strains of two different virus are mixed genetically to produce a different strain with the combination of surface antigens from both the parent virus. This causes phenotypic changes in the resulted strain of virus forming a subclass of virus.